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Sample records for central corneal thickness

  1. Central corneal thickness among glaucoma patients attending ...

    AAU_CHS

    ocular pressure measurement and is different among different ethnic population and subtypes of glaucoma. The central corneal thickness of different subtypes of glaucoma at Menelik II Hospital ... Intraocular pressure is a key element in the.

  2. Anatomical characterization of central, apical and minimal corneal thickness

    Federico Saenz-Frances

    2014-08-01

    Full Text Available AIM: To anatomically locate the points of minimum corneal thickness and central corneal thickness (pupil center in relation to the corneal apex.METHODS: Observational, cross-sectional study, 299 healthy volunteers. Thickness at the corneal apex (AT, minimum corneal thickness (MT and corneal thickness at the pupil center (PT were determined using the pentacam. Distances from the corneal apex to MT (MD and PT (PD were calculated and their quadrant position (taking the corneal apex as the reference determined:point of minimum thickness (MC and point of central thickness (PC depending on the quadrant position. Two multivariate linear regression models were constructed to examine the influence of age, gender, power of the flattest and steepest corneal axes, position of the flattest axis, corneal volume (determined using the Pentacam and PT on MD and PD. The effects of these variables on MC and PC were also determined in two multinomial regression models.RESULTS: MT was located at a mean distance of 0.909 mm from the apex (79.4% in the inferior-temporal quadrant. PT was located at a mean distance of 0.156 mm from the apex. The linear regression model for MD indicated it was significantly influenced by corneal volume (B=-0.024; 95%CI:-0.043 to -0.004. No significant relations were identified in the linear regression model for PD or the multinomial logistic regressions for MC and PC.CONCLUSION: MT was typically located at the inferior-temporal quadrant of the cornea and its distance to the corneal apex tended to decrease with the increment of corneal volume.

  3. Analysis of the horizontal corneal diameter, central corneal thickness, and axial length in premature infants

    Ozdemir Ozdemir

    2014-08-01

    Full Text Available Purpose: To determine the horizontal corneal diameter, central corneal thickness, and axial length in premature infants. Methods: Infants with a birth weight of less than 2,500 g or with a gestation period of less than 36 weeks were included in the study. Infants with retinopathy of prematurity (ROP were allocated to Group 1 (n=138, while those without ROP were allocated to Group 2 (n=236. All infants underwent a complete ophthalmologic examination, including corneal diameter measurements, pachymetry, biometry, and fundoscopy. Between-group comparisons of horizontal corneal diameter, central corneal thickness, and axial lengths were performed. Independent sample t-tests were used for statistical analysis. Results: Data was obtained from 374 eyes of 187 infants (102 female, 85 male. The mean gestational age at birth was 30.7 ± 2.7 weeks (range 25-36 weeks, the mean birth weight was 1,514 ± 533.3 g (range 750-1,970 g, and the mean postmenstrual age at examination was 40.0 ± 4.8 weeks. The mean gestational age and the mean birth weight of Group 1 were statistically lower than Group 2 (p0.05. Conclusions: The presence of ROP in premature infants does not alter the horizontal corneal diameter, central corneal thickness, or axial length.

  4. Correlation between central corneal thickness and myopia in Taiwan

    Yi-Chun Chen

    2014-01-01

    Full Text Available The aim of the study was to explore the correlation between central corneal thickness (CCT and the degree of myopia in Taiwanese adults. A total of 528 individuals were enrolled to undergo myopic laser refractive surgery from January 2004 to December 2006. Preoperative CCT was measured using the Orbscan corneal topography system and refractive status was determined by cycloplegic spherical equivalent. The relationship between CCT and refractive error was investigated by interindividual and intraindividual analyses. Participants had a mean age of 34.8 ± 7.3 years, and 79.9% were female. The mean refractive error was −7.27 ± 2.96 diopters and the mean CCT measurement was 560 ± 35 μm. CCT revealed that there was no association with age. However, CCT was significantly (p = 0.012 less in females than in males. The CCT also showed no significant association with refractive error (p = 0.49. Among the 67 participants with myopic anisometropia, the mean difference between both eyes was 3.09 ± 1.06 diopters. There was no association between the intereye CCT difference and refractive error (p = 0.57. The results remained the same after adjusting for age and sex. In conclusion, there was no correlation between CCT and the degree of myopia among adults in Taiwan. These data might contribute to the ongoing discussion about the role of CCT in the higher incidence of development and progression of glaucoma in myopic individuals.

  5. Clinical observation of cutting fluctuations on central corneal thickness after laser subepithelial keratomileusis

    Wei Cheng

    2017-09-01

    Full Text Available AIM:To evaluate the percentage of cutting fluctuations of central corneal thickness(CCTintraoperative used low concentration(0.02%mitomycin C(MMCafter laser-assisted subepithelial keratomileusis(LASEK. METHODS: In this prospective study, low and medium myopia group(spherical equivalent≤6.0DShas 138 patients(276 eyes. Low concentration MMC used topically in 69 patients(138 eyesrandomized after excimer laser ablation; the another traditional LASEK as control. High myopia group(6.0DSt test and their repeatability was assessed using the coefficient of variation(CV.RESULTS: At 3mo after operation, the difference of central corneal thickness and cutting value between different treatment groups was statistically significant(PPPPCONCLUSION: The study on percentage of cutting fluctuations of central corneal thickness, further confirmed low concentrations MMC in reducing postoperative corneal stromal proliferation reaction, inhibition of haze production.

  6. Central corneal thickness and related factors in an elderly American Chinese population.

    Wang, Dandan; Singh, Kuldev; Weinreb, Robert; Kempen, John; He, Mingguang; Lin, Shan

    2011-07-01

    To assess central corneal thickness and related factors in an elderly American Chinese population residing in San Francisco. Cross-sectional community based study. American Chinese aged 40 years and older were enrolled using random cluster sampling and volunteer screening in the Chinatown district of San Francisco. The following data were obtained: central corneal thickness by ultrasound pachymetry, intraocular pressure by Goldmann applanation tonometry, axial length by A-scan biometry, refractive status and corneal curvature by autorefractor. History of systemic and ocular diseases was collected via standard questionnaire. Central corneal thickness. Of 311 eligible subjects, 274 consented to study participation, and 228 phakic eyes were analyzed. Mean corneal thickness was 524.1 ± 31.1 µm, 545.5 ± 30.9 µm and 538.9 ± 31.8 µm in the sampling cluster, volunteer group and all subjects, respectively. A multiple linear regression model showed corneal thickness to be negatively associated with age (standardized regression coefficient [SRC] = -0.21; P = 0.016) and corneal curvature (SRC = -0.19; P = 0.018) but positively correlated with intraocular pressure (SRC = 0.20; P = 0.023). The distribution of central corneal thickness among this American Chinese population is similar to that reported in studies from East Asia. The independent factors associated with thinner corneas included older age, lower intraocular pressure and greater corneal curvature. While descendents of Chinese immigrants in America have, on average, thicker corneas than their ancestors, this phenomenon is potentially impacted by the level of intraocular pressure. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.

  7. Central Corneal Thickness And Its Relationship To Intra-ocular And Epidemiological Determinants

    Tayyab, A.; Masrur, A.

    2016-01-01

    Objective: To measure central corneal thickness in Pakistani population and determine its relationship to intra-ocular pressure, age, gender and ethnicity. Study Design: Cross-sectional observation study. Place and Duration of Study: Pakistan Institute of Medical Sciences, Islamabad, Pakistan, between December 2013 and February 2015. Methodology: The right eyes of 1000 cases (496 males and 504 females) were recruited for this study. Inclusion criteria were Pashtun or Punjabi ethnicity, intra-ocular pressure < 22 mmHg, gonioscopically open angles, cup-disk-ratio < 0.5, and age matched normal visual fields. Cases with prior ocular surgery, contact lens use, corneal pathologies, myopia or hypermetropia > ±3.0 diopters, astigmatism of > ±1.0 diopters were excluded. Central corneal thickness was measured using a TopCon non-contact specular microscope. Intra-ocular pressure was measured using Goldmann applanation tonometer. Frequency distribution, test of significance, and regression analysis was carried out using Statistical Package for Social Sciences version 20.0. Result: Mean age was 47.31 ±11.78 years. Ethnic composition was 51.6 percentage (n=516) Pashtun and 48.4 percentage (n=484) Punjabi. The mean central corneal thickness was 503.96 (±12.47) meu m, while the mean intra-ocular pressure was 15.61 (±2.68) mmHg. Regression analysis showed a significant association between central corneal thickness and intra-ocular pressure (p=0.00) and age (p=0.00). A ±100 μ change in central corneal thickness was associated with change in IOP of ±3.30 mmHg, whereas central corneal thickness decreased by 0.12 meu m per year. No significant association could be established between central corneal thickness and ethnicity (p=0.19). Conclusion: Central corneal thickness of the studied races was comparable to non-Caucasians which affects intra-ocular pressure measurements, and decreases with increasing age. No relationship was observed between central corneal thickness and

  8. Central Corneal Thickness Measurement by Ultrasound versus Orbscan II

    Amir Faramarzi

    2008-12-01

    Full Text Available

    PURPOSE: To compare Orbscan II and ultrasonic pachymetry for measurement of central corneal thickness (CCT in eyes scheduled for keratorefractive surgery. METHODS: CCT was measured using Orbscan II (Bausch & Lomb, USA and then by ultrasonic pachymetry (Tomey SP-3000, Tomey Ltd, Japan in 100 eyes of 100 patients with no history of ocular surgery scheduled for excimer laser refractive surgery. RESULTS: Mean CCT was 544.7±35.5 (range 453-637 µm by ultrasonic pachymetry versus 546.9±41.6 (range 435-648 µm measured by Orbscan II applying an acoustic factor of 0.92 (P=0.14. The standard deviation of measurements was greater with Orbscan pachymetry but the difference was not statistically significant. CONCLUSION: CCT measurements by Orbscan II (applying an acoustic factor and by ultrasonic pachymetry are not significantly different; however, when CCT readings by Orbscan II are in the lower range, it is advisable to recheck the measurements using ultrasonic pachymetry.

  1. Central corneal thickness measurements in unoperated eyes and eyes after PRK for myopia using Pentacam, Orbscan II, and ultrasonic pachymetry.

    Kim, Sun Woong; Byun, Yeo Jue; Kim, Eung Kweon; Kim, Tae-im

    2007-11-01

    To compare central corneal thickness measurements obtained in unoperated eyes and eyes after myopic photorefractive keratectomy (PRK) using a rotating Scheimpflug camera (Pentacam), a scanning slit corneal topography system (Orbscan II), and ultrasonic pachymetry. Corneal thickness was measured using Pentacam, Orbscan II, and ultrasonic pachymetry in 25 unoperated eyes (unoperated group), 24 eyes 1 to 3 months after myopic PRK (early postoperative PRK group), and 21 eyes 4 months or more after myopic PRK (late postoperative PRK group). In the unoperated group, corneal thickness measurements were similar for all three methods (P=.125). In the early postoperative PRK group, Orbscan measurements were thinner than Pentacam and ultrasonic measurements by a mean of 69.4 microm and 63.4 microm (PPRK group, Orbscan measurements were thinner than Pentacam measurements by a mean of 36.0 microm (P=.017). Pentacam and ultrasonic pachymetry measurements were similar for all three groups with a mean difference of approximately 10 microm. Following myopic PRK, Pentacam was comparable to ultrasonic pachymetry in measuring corneal thickness, whereas Orbscan measurements were thinner.

  2. The Effect of Pseudoexfoliation and Pseudoexfoliation Induced Dry Eye on Central Corneal Thickness.

    Akdemir, M Orcun; Kirgiz, Ahmet; Ayar, Orhan; Kaldirim, Havva; Mert, Metin; Cabuk, Kubra Serefoglu; Taskapili, Muhittin

    2016-01-01

    The aim of this study is to investigate the effect of pseudoexfoliation (PEX) and PEX-induced dry eye on central corneal thickness (CCT). This cross-sectional study consists of total 270 eyes of 135 patients (67 females, 68 males) in total. After excluding the PEX (-) 32 eyes with PEX in the other eye, totally 130 eyes in PEX (-) group and 108 eyes in the PEX (+) group were included in the study. The PEX (+) group was regrouped as PEX syndrome (80 eyes of 50 patients) and PEX glaucoma (28 eyes of 20 patients). In the PEX (-) group, the mean Schirmer test result was 12 ± 4 mm (4-25 mm), in the PEX syndrome group 10 ± 4 mm (4-22 mm), in the PEX glaucoma group 9 ± 3 mm (4-15 mm). The difference among the PEX (-) group, the PEX syndrome and the PEX glaucoma groups was statistically significant (p eyes with PEX (r = 0.307, p = 0.001). However, there was no statistically significant correlation between CCT, Schirmer and tear break up time tests in the eyes with PEX. PEX material can cause decrease in tear film secretion and disturb tear film stability. There is no effect of PEX-induced dry eye on CCT. Lower CCT values in the eyes with PEX material may be a result of decrease in corneal stromal cell density. Moreover, higher CCT values may be because of decreased endothelial cells in PEX glaucoma patients.

  3. Precision of high definition spectral-domain optical coherence tomography for measuring central corneal thickness.

    Correa-Pérez, María E; López-Miguel, Alberto; Miranda-Anta, Silvia; Iglesias-Cortiñas, Darío; Alió, Jorge L; Maldonado, Miguel J

    2012-04-06

    This study was intended to assess the reliability of central corneal thickness (CCT) measurements using Cirrus high-definition optical coherence tomography (HD-OCT) in healthy subjects and its accuracy compared with ultrasonic pachymetry. Seventy-seven consecutive subjects were recruited for evaluating repeatability, and agreement between two examiners. To analyze repeatability, one examiner measured 77 eyes four times in succession. To study agreement between two observers, a second independently trained examiner obtained another CCT measurement. We also measured eyes in a subgroup of 20 patients using standard ultrasonic pachymetry. Within-subject standard deviation (S(w)), coefficient of variation (CV), limits of agreement (LoA), and intraclass correlation coefficient (ICC) data were obtained. For repeatability, the S(w) and precision (1.96 × S(w)) were 4.86 and 9.52 μm, respectively. Intraobserver CV was 0.89% and the ICC was 0.98 (95% confidence interval [CI], 0.97-0.99). For agreement between two examiners, the S(w) and precision were 7.58 and 14.85 μm, respectively; the CV was 1.40%. The mean difference between observers was -0.13 μm (95% CI, -1.85 to 1.58; P = 0.87). The width of the LoA was 29.64 μm. Median difference between Cirrus HD-OCT and ultrasound CCT measurements was -4.5 μm (interquartile range, -7.0-0.0; P = 0.04). Cirrus HD-OCT provides repeatable CCT measurements, good agreement between two independently trained examiners, and its systematic bias compared to ultrasonic pachymetry is clinically negligible. Therefore, research laboratories and eye clinics using Cirrus HD-OCT as a diagnostic imaging method, can also benefit from a reliable noncontact pachymeter when counseling patients with glaucoma and those undergoing corneal and refractive surgeries.

  4. Comparison of Pre-operative Central Corneal Thickness in Pediatric Cataract Cases versus Normal

    Khan, S.; Ali, M.; Zaheer, N.

    2014-01-01

    Objective: To compare the pre-operative central corneal thickness (CCT) in paediatric cataract patients with reference to normal control group. Study Design: A case control study. Place and Duration of Study: Paediatric Ophthalmology Clinic of Al-Shifa Trust Eye Hospital (ASTEH), Rawalpindi, from November 2009 to May 2010. Methodology: The study included 116 subjects with equal number of cases and controls. Demographic profile of all the subjects was noted followed by history and detailed ophthalmic examination. CCT was measured using an ultrasonic pachymeter (model Pac Scan 300). The mean of three measurements from the central cornea were recorded in microns. Results were analyzed using SPSS version 17.0. Results: Mean CCT values of the cases was 566.83 +- 37.646 microns while the control group had a mean CCT of 535.81 +- 24.466 microns. Difference between the CCT values of the two groups was highly significant (p < 0.001). Conclusion: Eyes with congenital cataracts have greater CCT values as compared to normal paediatric population. This factor must be kept in mind while interpreting intra-ocular pressure in such patients. (author)

  5. Ethnic differences of intraocular pressure and central corneal thickness: the Singapore Epidemiology of Eye Diseases study.

    Chua, Jacqueline; Tham, Yih Chung; Liao, Jiemin; Zheng, Yingfeng; Aung, Tin; Wong, Tien Yin; Cheng, Ching-Yu

    2014-10-01

    To determine the ethnic differences in the distribution of intraocular pressure (IOP) and central corneal thickness (CCT) in a multi-ethnic Asian population by self-reported ethnicity and genetic ancestry. Population-based, cross-sectional study. A total of 10 033 adults (3353 Chinese, 3280 Malays, and 3400 Indians) aged >40 years. Participants underwent standardized systemic and ocular examinations and interviewer-administered questionnaires for risk factor assessment. The IOP readings were obtained by Goldmann applanation tonometry (Haag-Streit, Konig, Switzerland) before pupil dilation. The CCT was measured with ultrasound pachymetry. Genetic ancestry was derived using principal component (PC) analysis. Regression models were used to investigate the association of IOP and CCT with potential risk factors and genetic ancestry. Intraocular pressure and CCT. After excluding participants with a history of glaucoma surgery or medication, refractive surgery, corneal edema, or corneal dystrophy, IOP and CCT readings were available for 3251 Chinese, 3232 Malays, and 3317 Indians. The mean IOP readings in the Chinese, Malay, and Indian participants were 14.3±3.1, 15.3±3.7, and 15.8±2.9 mmHg, respectively (P Chinese, 6.2% in Malays, and 4% in Indians (P Malay and Indian participants on average had 0.81 and 1.43 mmHg higher IOP levels, respectively, than Chinese (P Chinese, 540.9±33.6 μm in Malays, and 540.4±33.6 μm in Indians (P Chinese, 68.5% in Malays, and 66.2% in Indians (P Chinese have the thickest CCT but lowest IOP among the 3 major ethnic groups. In addition, there is a higher proportion of Malays with IOP ≥21 mmHg and CCT Chinese or Indians. This disparity across ethnic groups should be taken into account by future studies investigating IOP and CCT as risk factors or diagnostic tests for glaucoma in Asian populations. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  6. Changes in central corneal thickness and endothelial cell count pediatric cataract surgery

    Memon, M.N.

    2015-01-01

    To evaluate the mean changes in Central Corneal Thickness (CCT) and Endothelial Cell Count (ECC) in eyes after pediatric cataract surgery with foldable intraocular lens using scleral tunnel incision micro-surgical technique. Study Design: Qausi experimental study. Place and Duration of Study: Department of Pediatric Ophthalmology and Strabismus, Al-Shifa Trust Eye Hospital, Rawalpindi, from May 2011 to March 2012. Methodology: Fifty-two eyes of 37 children with pediatric cataract were included in the study. Extracapsular Cataract Extraction (ECE) with foldable Intra Ocular Lens (IOL) implantation using sclera tunnel incision was performed in all children. Endothelial Cell Count (ECC) and Central Corneal Thickness (CCT) were recorded before surgery and 1 month, 3 months and 6 months after surgery and the effect of currently practiced surgical technique on ECC and CCTwas evaluated. Results: The mean age at the time of surgery was 8.8 ± 2.7 years (range: 4 to 15 years). The postoperative ECC and CCT were significantly different from the pre-operative values. Mean pre-operative ECC was 3175.3 ± 218.4 cell/mm2 and in first postoperative month the mean ECC was 3113.4 ± 210.8 cell/mm2 (p<0.0001). In the 3rd and 6th month postoperative means ECC were 3052 ± 202.5 cell/mm2 (p<0.0001) and 3015 ±190.6 cell/mm2 (p<0.0001), respectively. The mean cell loss at first postoperative month was 1.95% and at 3rd and 6th postoperative month were 3.9% and 5.05%, respectively. Mean pre-operative CCT was 514 ± 49.9 micro m and first postoperative mean CCT after 1 month was 524.1 ± 25 micro m (p = 0.084). After the 3rd and 6th months postoperative, mean CCT were 527.3 ± 24.6 micro m, and 530 ± 24.5 micro m, respectively. Third and 6th months postoperative means were significantly higher than baseline CCT, p = 0.024 and 0.007, respectively. Conclusion: Endothelial cell loss with closed chamber micro-surgical technique using scleral tunnel incision is within acceptable limits and

  7. Central corneal thickness and anterior chamber depth measurement by Sirius® Scheimpflug tomography and ultrasound

    Jorge J

    2013-02-01

    Full Text Available J Jorge,1 JL Rosado,2 JA Díaz-Rey,1 JM González-Méijome11Clinical and Experimental Optometry Research Laboratory, Center of Physics (Optometry, School of Sciences, University of Minho, Braga, 2Opticlinic, Lisboa, PortugalBackground: The purpose of this study was to compare the accuracy of the new Sirius® Scheimpflug anterior segment examination device for measurement of central corneal thickness (CCT and anterior chamber depth (ACD with that of CCT measurements obtained by ultrasound pachymetry and ACD measurements obtained by ultrasound biometry, respectively.Methods: CCT and ACD was measured in 50 right eyes from 50 healthy subjects using a Sirius Scheimpflug camera, SP100 ultrasound pachymetry, and US800 ultrasound biometry.Results: CCT measured with the Sirius was 546 ± 39 µm and 541 ± 35 µm with SP100 ultrasound pachymetry (P = 0.003. The difference was statistically significant (mean difference 4.68 ± 10.5 µm; limits of agreement −15.8 to 25.20 µm. ACD measured with the Sirius was 2.96 ± 0.3 mm compared with 3.36 ± 0.29 mm using US800 ultrasound biometry (P < 0.001. The difference was statistically significant (mean difference −0.40 ± 0.16 mm; limits of agreement −0.72 to 0.07 mm. When the ACD values obtained using ultrasound biometry were corrected according to the values for CCT measured by ultrasound, the agreement increased significantly between both technologies for ACD measurements (mean difference 0.15 ± 0.16 mm; limits of agreement −0.16 to 0.45 mm.Conclusion: CCT and ACD measured by Sirius and ultrasound methods showing good agreement between repeated measurements obtained in the same subjects (repeatability with either instrument. However, CCT and ACD values, even after correcting ultrasound ACD by subtracting the CCT value obtained with either technology should not be used interchangeably.Keywords: Scheimpflug corneal tomography, ultrasound biometry, ultrasound pachymetry, limits of agreement

  8. Ethnic Variations in Central Corneal Thickness in a Rural Population in China: The Yunnan Minority Eye Studies

    Pan, Chen-Wei; Li, Jun; Zhong, Hua; Shen, Wei; Niu, Zhiqiang; Yuan, Yuansheng; Chen, Qin

    2015-01-01

    Purpose To describe the ethnic differences in central corneal thickness (CCT) in population-based samples of ethnic Bai, Yi and Han people living in rural China. Methods 6504 adults (2119 ethnic Bai, 2202 ethnic Yi and 2183 ethnic Han) aged 50 years or older participated in the study. Each subject underwent standardized ocular examinations and interviewer-administered questionnaires for risk factor assessment. CCT was measured for both eyes using an ultrasound pachymeter. Regression and princ...

  9. Comparison of central corneal thickness with four noncontact devices: An agreement analysis of swept-source technology

    Erhan Ozyol; Pelin Özyol

    2017-01-01

    Purpose: The purpose of this study was to compare the central corneal thickness (CCT) measurements of four noncontact devices in healthy eyes. Materials and Methods: In a sample of 45 healthy controls, CCT was measured using an optical biometer (IOLMaster 700) based on swept-source optical coherence tomography (SS-OCT), high-resolution rotating Scheimpflug camera system (Pentacam HR), spectral-domain OCT (SD-OCT) device with an anterior segment module (Spectralis), and noncontact pachymetry (...

  10. Accuracy of Cirrus HD-OCT and Topcon SP-3000P for measuring central corneal thickness.

    Calvo-Sanz, Jorge A; Ruiz-Alcocer, Javier; Sánchez-Tena, Miguel A

    2017-02-18

    To compare and analyze the interchangeability of three measuring systems, each based on a different technique, for central corneal thickness (CCT) analysis. CCT measurements were measured using optical coherence tomography (OCT), non-contact specular microscopy (NCSM), and ultrasonic pachymetry (USP) in 60 eyes of 60 healthy patients with a mean age of 66.5±15.0 years and a mean spherical equivalent of 0.43±1.14 D. Analysis of variations in measurement concordance and correlation among the three different methods were performed. Comparison of CCT measurements were done using Bland-Altman plots (with bias and 95% confidence intervals), intraclass correlation coefficient (ICC), and paired t-student analysis. Mean CCT values were: 549.20±26.91μm for USP (range 503-618μm), 514.20±27.49μm for NCSM (range 456-586μm) and 542.80±25.56μm for OCT (range 486-605μm). CCT values obtained with NCMS were significantly lower than those obtained with OCT and USP methods. NCMS CCT value was 36.08±10.72μm lower than USP value (p<0.05), and NCMS CCT value was 7.88±8.86μm lower than OCT value (p<0.05). ICC between USP-NCSM pair was 0.488 and 0.909 between USP-OCT pair. OCT and UPS offered highly comparable results, whereas NCSM offered lower mean CCT values compared to the other two methods. Therefore, NCSM should not be considered a reliable method for measuring CCT and should rather be considered for assessing longitudinal changes in the same patient. Copyright © 2017 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  11. Comparison of central corneal thickness measured by Lenstar LS900, OrbscanⅡ and ultrasonic pachmetry

    Hong-Tao Zhang

    2013-09-01

    Full Text Available AIM: To investigate the difference of central corneal thickness(CCTmeasured by Lenstar LS900, OrbscahⅡ system and ultrasonic pachmetry, and to evaluate the correlation and consistency of the results for providing a theoretical basis for clinical application.METHODS: The mean value of CCT in 70 eyes of 35 patients measured three times by Lenstar LS900, OrbscahⅡ system and ultrasonic pachmetry underwent statistical analysis. The difference of CCT was compared, and the correlation and consistency of three measurements were analyzed to provide theoretical basis for clinical application. CCT values measured by different methods were analyzed with randomized block variance analysis. LSD-t test was used for pairwise comparison between groups. The correlation of three measurement methods were analyzed by linear correlation analysis, and Bland-Altman was used to analyze the consistency.RESULTS: The mean CCT values measured by Lenstar LS900, OrbscanⅡ and ultrasonic pachmetry were 542.75±40.06, 528.74±39.59, 538.54±40.93μm, respectively. The mean difference of CCT measurement was 4.21±8.78μm between Lenstar LS900 and ultrasonic pachmetry, 14.01±13.39μm between Lenstar LS900 and Orbscan Ⅱ, 9.8±10.57μm between ultrasonic pachmetry and Orbscan Ⅱ. The difference was statistically significant(PP>0.05: There was positive correlation between CCT with Lenstar LS900 and ultrasonic pachmetry(r=0.977, 0.944; PCONCLUSION: There are excellent correlation among Lenstar LS900, Orbscan Ⅱ and ultrasonic pachmetry. Lenstar LS900 can be used as CCT non-contact measurement tool.

  12. The influence of central corneal thickness and age on intraocular pressure measured by pneumotonometry, non-contact tonometry, the Tono-Pen XL, and Goldmann applanation tonometry

    Tonnu, P-A; Ho, T; Newson, T; El Sheikh, A; Sharma, K; White, E; Bunce, C; Garway-Heath, D

    2005-01-01

    Aims: To evaluate the influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurements made with the Goldmann applanation tonometer (GAT), Tono-Pen XL, ocular blood flow tonograph (OBF), and Canon TX-10 non-contact tonometer (NCT).

  13. Ocular biometry and central corneal thickness in children: a hospital-based study

    Adem Gul

    2014-06-01

    Full Text Available Objetivo: Investigar a distribuição do comprimento axial, profundidade da câmara anterior, espessura do cristalino, profundidade da câmara vítrea e espessura corneal central em crianças em diferentes faixas etárias. Métodos: Foram estudados 364 olhos de 182 crianças entre 1 e 12 anos de idade. O comprimento axial, a profundidade da câmara anterior , a espessura do cristalino e a profundidade da câmara vítrea foram medidos por biometria ultrassônica. A espessura corneal central foi medida por paquimetria ultrassônica em todas as crianças. Resultados: A idade média foi de 6,54 ± 3,42 anos. O comprimento axial foi 20,95 mm no grupo de 1-2 anos de idade e 22,95 mm no grupo de 11-12 anos de idade. A espessura corneal central foi 556 µm no grupo de 1-2 anos de idade e 555 µm no grupo de 11-12 anos de idade. A profundidade da câmara anterior média e profundidade da câmara vítrea aumentou com a idade (3,06 mm a 3,44 mm de profundidade da câmara anterior, 13,75 mm a 15,99 mm de profundidade da câmara vítrea e da espessura do cristalino diminuiu com o aumento da idade (3,67 mm a 3,51 mm. Conclusões: Em nosso estudo, os valores do comprimento axial aumentou com a idade e atingiu os níveis adultos aos 9-10 anos de idade. A espessura do cristalino diminuiu gradualmente até os 12 anos de idade. As medições de espessura corneal central não seguiu um algoritmo linear.

  14. Comparison of Central Corneal Thickness Measured by Standard Ultrasound Pachymetry, Corneal Topography, Tono-Pachymetry and Anterior Segment Optical Coherence Tomography.

    González-Pérez, Javier; Queiruga Piñeiro, Juan; Sánchez García, Ángelx; González Méijome, José Manuel

    2018-04-10

    To compare central corneal thickness (CCT) measured by standard ultrasound pachymetry (USP), and three non-contact devices in healthy eyes. A cross-sectional study of CCT measurement in 52 eyes of 52 healthy volunteers was done by a single examiner at Ocular Surface and Contact Lens Laboratory. Three consecutive measurements were done by standard USP, non-contact tono-pachymeter, Pentacam corneal topographer, and Anterior Segment Optical Coherence Tomography (AS-OCT). The mean values were used for assessment. The results were compared using multivariate ANOVA, linear regression, and Pearson correlation. Agreement among the devices was analyzed using mean differences and Bland-Altman analysis with 95% limits of agreement (LoA). Finally, reliability was analyzed using intraclass correlation coefficient (ICC). Mean CCT by ultrasound pachymeter, tono-pachymeter, corneal topographer and AS-OCT were 558.9 ± 31.2 µm, 525.8 ± 43.1 µm, 550.4 ± 30.5 µm, and 545.9 ± 30.5 µm respectively. There was a significant positive correlation between AS-OCT and USP (Pearson correlation = 0.957, p device, and USP. Mean CCT among USP, Pentacam and AS-OCT were comparable and had significant linear correlations. In clinical practice, these three modalities could be interchangeable in healthy patients.

  15. Correlation between central corneal thickness and visual field defects, cup to disc ratio and retinal nerve fiber layer thickness in primary open angle glaucoma patients.

    Sarfraz, Muhammad Haroon; Mehboob, Mohammad Asim; Haq, Rana Intisar Ul

    2017-01-01

    To evaluate the correlation between Central Corneal Thickness (CCT) and Visual Field (VF) defect parameters like Mean Deviation (MD) and Pattern Standard Deviation (PSD), Cup-to-Disc Ratio (CDR) and Retinal Nerve Fibre Layer Thickness (RNFL-T) in Primary Open-Angle Glaucoma (POAG) patients. This cross sectional study was conducted at Armed Forces Institute of Ophthalmology (AFIO), Rawalpindi from September 2015 to September 2016. Sixty eyes of 30 patients with diagnosed POAG were analysed. Correlation of CCT with other variables was studied. Mean age of study population was 43.13±7.54 years. Out of 30 patients, 19 (63.33%) were males and 11 (36.67%) were females. Mean CCT, MD, PSD, CDR and RNFL-T of study population was 528.57±25.47µm, -9.11±3.07, 6.93±2.73, 0.63±0.13 and 77.79±10.44µm respectively. There was significant correlation of CCT with MD, PSD and CDR (r=-0.52, pfield parameters like mean deviation and pattern standard deviation, as well as with cup-to-disc ratio. However, central corneal thickness had no significant relationship with retinal nerve fibre layer thickness.

  16. Variation of central corneal thickness in patients with diabetic retinopathy as detected by ultrasonic pachymetry in patients presenting to a tertiary care hospital

    Khan, S.A.

    2017-01-01

    To compare the central corneal thickness between patients with diabetic retinopathy and non diabetics. Study Design: A cross sectional study. Place and Duration of Study: Lahore General Hospital Lahore, from 1st Dec 2015 to 31st May 2016. Material and Methods: A cross-sectional study was conducted in the ophthalmology outpatient department of Lahore General Hospital. A total of one hundred and fifty subjects from different age groups were selected for the study. An ultrasound pachymeter was used to measure CCT. There were two groups for sample, 75 were patients with diabetic retinopathy and 75 of them were non-diabetic subjects. Results: The diabetic patients had average central corneal thickness of value 554.93 +- 33.73 microns. The average central corneal thickness found in non-diabetic patients was 520.41 +- 26.06 microns. The diabetic patients showed an increased central corneal thickness as compared to non-diabetics. The result of this study was statistically significant (p=0.001). Conclusion: The diabetic patients showed an increased central corneal thickness as compared to non-diabetic patients. (author)

  17. Ocular dimensions, corneal thickness, and corneal curvature in quarter horses with hereditary equine regional dermal asthenia.

    Badial, Peres R; Cisneros-Àlvarez, Luis Emiliano; Brandão, Cláudia Valéria S; Ranzani, José Joaquim T; Tomaz, Mayana A R V; Machado, Vania M; Borges, Alexandre S

    2015-09-01

    The aim of this study was to compare ocular dimensions, corneal curvature, and corneal thickness between horses affected with hereditary equine regional dermal asthenia (HERDA) and unaffected horses. Five HERDA-affected quarter horses and five healthy control quarter horses were used. Schirmer's tear test, tonometry, and corneal diameter measurements were performed in both eyes of all horses prior to ophthalmologic examinations. Ultrasonic pachymetry was performed to measure the central, temporal, nasal, dorsal, and ventral corneal thicknesses in all horses. B-mode ultrasound scanning was performed on both eyes of each horse to determine the dimensions of the ocular structures and to calculate the corneal curvature. Each corneal region examined in this study was thinner in the affected group compared with the healthy control group. However, significant differences in corneal thickness were only observed for the central and dorsal regions. HERDA-affected horses exhibited significant increases in corneal curvature and corneal diameter compared with unaffected animals. The ophthalmologic examinations revealed mild corneal opacity in one eye of one affected horse and in both eyes of three affected horses. No significant between-group differences were observed for Schirmer's tear test, intraocular pressure, or ocular dimensions. Hereditary equine regional dermal asthenia-affected horses exhibit decreased corneal thickness in several regions of the cornea, increased corneal curvature, increased corneal diameter, and mild corneal opacity. Additional research is required to determine whether the increased corneal curvature significantly impacts the visual accuracy of horses with HERDA. © 2014 American College of Veterinary Ophthalmologists.

  18. Inter-instrument agreement and influence of central corneal thickness on measurements with Goldmann, pneumotonometer and noncontact tonometer in glaucomatous eyes.

    Gupta, Viney; Sony, Parul; Agarwal, Harish C; Sihota, Ramanjit; Sharma, Ajay

    2006-12-01

    This study was conducted to compare the intraocular pressure (IOP) measurements by the Goldman applanation tonometer (GAT), non contact tonometer (NCT) and the ocular blood flow (OBF) pneumotonometer in different IOP ranges in glaucomatous eyes. The effect of central corneal thickness (CCT) on IOP measurement in chronic glaucomatous eyes using the three different tonometers was also evaluated. IOP measurements of 130 eyes of primary glaucoma patients were performed using GAT by an ophthalmologist while NCT and OBF-pneumotonometer measurements were performed by an experienced optometrist. The IOP values were compared amongst the three instruments in the three different IOP ranges (0-18 mmHg, > 18 to 25 mmHg, > 25 mmHg). CCT was also measured in all patients. The mean of paired difference between GAT and NCT was 0.9 +/- 3.1 mmHg while that between GAT and OBF-pneumotonometer was 0.3 +/- 3.4 mmHg. The OBF-pneumotonometer and NCT were more affected by corneal thickness (0.41 mmHg and 0.4 mmHg / 10 micro corneal thickness respectively) while GAT was the least affected by corneal thickness (0.3 mmHg / 10 micro corneal thickness) though the difference was not statistically significant ( P =0.42). With appropriate correction for corneal thickness the NCT and OBF-pneumotonometer can be used as reliably as GAT in following up glaucomatous patients.

  19. Inter-instrument agreement and influence of central corneal thickness on measurements with Goldmann, pneumotonometer and noncontact tonometer in glaucomatous eyes

    Gupta Viney

    2006-01-01

    Full Text Available Purpose: This study was conducted to compare the intraocular pressure (IOP measurements by the Goldman applanation tonometer (GAT, non contact tonometer (NCT and the ocular blood flow (OBF pneumotonometer in different IOP ranges in glaucomatous eyes. The effect of central corneal thickness (CCT on IOP measurement in chronic glaucomatous eyes using the three different tonometers was also evaluated. Materials and Methods: IOP measurements of 130 eyes of primary glaucoma patients were performed using GAT by an ophthalmologist while NCT and OBF-pneumotonometer measurements were performed by an experienced optometrist. The IOP values were compared amongst the three instruments in the three different IOP ranges (0-18 mmHg,> 18 to 25 mmHg, > 25 mmHg. CCT was also measured in all patients. Results: The mean of paired difference between GAT and NCT was 0.9 ± 3.1 mmHg while that between GAT and OBF-pneumotonometer was 0.3 ± 3.4 mmHg. The OBF-pneumotonometer and NCT were more affected by corneal thickness (0.41 mmHg and 0.4 mmHg / 10 µ corneal thickness respectively while GAT was the least affected by corneal thickness (0.3 mmHg / 10 µ corneal thickness though the difference was not statistically significant ( P =0.42. Conclusion: With appropriate correction for corneal thickness the NCT and OBF-pneumotonometer can be used as reliably as GAT in following up glaucomatous patients.

  20. [Effects of central corneal thickness and corneal curvature on measurement of intraocular pressure with Goldmann applanation tonometer and non-contact tonometer].

    Zhang, Yang; Zhao, Jia-liang; Bian, Ai-ling; Liu, Xiao-li; Jin, Yu-mei

    2009-08-01

    To investigate the effects of central corneal thickness (CCT) and corneal curvature (CC) on intraocular pressure (IOP) measurements by the Goldmann applanation tonometer (GAT) and the non-contact tonometer (NCT). One hundred and twenty patients were recruited from the clinic of Peking Union Medical College Hospital. The CCT was measured by ultrasound pachymetry and the mean radius of CC by using Canon PK-5 refractometer. The IOP of each eye was measured by both GAT and NCT. Linear regression was used to compare the measurements of GAT and NCT; multi regression was used to analyze the relationships between CCT, CC and the measurements of GAT and NCT. Bland-Altman method was used to compare the effect of NCT and GAT on the IOP measurements. The results of the right eyes were reported in this paper. The mean and standard deviation of IOP measured by GAT and NCT was (18.4 + or - 4.0) mm Hg (1 mm Hg = 0.133 kPa) and (17.0 + or - 4.6) mm Hg, respectively, the difference was statistically significant (r = 0.835, P = 0.000). IOP measured using GAT increased by 0.039 mm Hg per microm increase in CCT. IOP measured using NCT increased by 0.064 mm Hg per microm increase in CCT. For an increase of 1 mm of mean corneal curvature there was decrease in IOP of 2.648 mm Hg measured by the GAT and of 3.190 mm Hg measured by the NCT. Compared to the GAT, NCT underestimated at low IOP level and overestimated at higher IOP level. The IOP measurement obtained with both GAT and NCT varied with CCT and CC. CCT affected IOP measurements by NCT more than that by GAT.

  1. Comparación de los valores del espesor corneal central según los equipos Lenstar, Galilei y Pentacam Comparative study of the central corneal thickness measurements taken by Lenstar, Gallilei and Pentacam equipment

    Iramis Miranda Hernández

    2012-06-01

    Full Text Available Objetivo: Comparar valores del espesor corneal central obtenidos mediante la paquimetría con el sistema de interferometria de coherencia parcial (Lenstar con los sistemas Scheimpflug (Pentacam; Oculus y Galilei (Ziemer, Suiza. Métodos: Se realizó un estudio prospectivo, comparativo en 120 ojos de 60 pacientes. Para la comparación se tomaron varias mediciones recomendadas por los fabricantes para probar la eficacia del equipo con el nuevo biómetro Lenstar LS 900 (Haag Streit AG y con los equipos Pentacam y Galilei. La comparación de los valores se realizó mediante el análisis de regresión lineal y correlación de Pearson. Resultados: El análisis reveló que existe una alta correspondencia en los valores del espesor corneal central entre Lenstar y los topógrafos Galilei y Pentacam. Conclusiones: Existe una alta correspondencia entre los valores del espesor corneal central obtenidos por los equipos Lenstar, Pentacam y Galilei. Por esto el equipo Lenstar es útil en la cirugía de catarata y la cirugía refractiva.Objective: To compare the central corneal thickness measurements taken by pachimetry with the partial coherence interferometry, Lenstar and with Scheimpflug systems (Pentacam; Oculus and Galilei (Ziemer, Switzerland. Methods: Comparative and prospective study of 120 eyes from 60 patients. Several recommended measurements were taken with the optical biometers LenstarLS 900 (Haag Streit AG and with Pentacam y Galilei topographers. The results were evaluated using the linear regresión analysis and Pearson´s correlation. Results: There is high correlation among the central corneal thickness measurements taken by the Lenstar equipment and topographers Pentacam and Galilei. Conclusion: The new biometer LENSTAR provided results that correlated very well with those of the Pentacam and Galilei systems. The Lenstar is a precise device that will be helpful for any cataract or refractive surgery.

  2. The evaluation of central corneal thickness and intraocular pressure in conjunction with tear IGF-1 levels in patients with acromegaly.

    Kan, Emrah; Kan, Elif K; Okuyucu, Ali

    2017-08-30

    To compare the central corneal thickness (CCT), intraocular pressure (IOP), and tear insulin-like growth factor 1 (IGF-1) levels between patients with acromegaly and a control group and to evaluate the possible effect of tear IGF-1 and duration of the disease on CCT and IOP. We included 31 patients with acromegaly (study group) and 40 age- and sex-matched controls in the study. Patients with acromegaly were divided into 2 subgroups based on disease status (active/inactive). All participants underwent complete ophthalmologic evaluation including CCT and IOP values. Basal tear samples were collected from both groups and tear IGF-1 levels were measured. The CCT, IOP, and tear IGF-1 levels were compared between groups and subgroups and the association between tear IGF-I levels and ocular parameters (CCT, IOP) and disease duration were also evaluated. Central corneal thickness, IOP, and tear IGF-1 levels did not show a significant difference between study and control groups. We also did not find a significant difference in terms of CCT, IOP, or tear IGF-1 levels between subgroups of patients. Correlation analysis did not show an association between the duration of disease and tear IGF-1 levels with CCT or IOP. There was no significant difference in tear IGF-1 levels between patients with acromegaly and controls. Additionally, there was no correlation between disease duration and tear IGF-1 levels with CCT or IOP levels. This lack of association may suggest that tear IGF-1 levels might not have an effect on CCT or IOP findings in patients with acromegaly.

  3. Ethnic Variations in Central Corneal Thickness in a Rural Population in China: The Yunnan Minority Eye Studies.

    Chen-Wei Pan

    Full Text Available To describe the ethnic differences in central corneal thickness (CCT in population-based samples of ethnic Bai, Yi and Han people living in rural China.6504 adults (2119 ethnic Bai, 2202 ethnic Yi and 2183 ethnic Han aged 50 years or older participated in the study. Each subject underwent standardized ocular examinations and interviewer-administered questionnaires for risk factor assessment. CCT was measured for both eyes using an ultrasound pachymeter. Regression and principal component analysis were performed to examine the relationship of ethnicity and other factors with CCT.The mean CCT readings were 536.4 ± 34.2 μm in ethnic Bai, 532.1 ± 32.1 μm in ethnic Yi and 529.6 ± 32.7 μm in ethnic Han adults (P<0.001, respectively. There was a decreasing trend of mean CCT with increasing age across all ethnic groups. In multivariate linear regression models, increasing CCT was associated with younger age (P<0.001, male gender (P<0.001, Bai (P<0.001 or Yi (P<0.001 ethnicity, greater body mass index (P<0.001, higher systolic blood pressure (P<0.001, greater corneal curvature (P<0.001, deeper anterior chamber (P < 0.001, and thicker lens (P<0.001. Ethnicity contributed significantly to presence of thin cornea (60%; P< 0.001 compared with other factors. CCT had similar impact on intraocular pressure readings across all ethnic groups.This study of more than 6500 multiethnic participants demonstrates significant ethnic variations in CCT, with Han ethnicity having the thinnest cornea compared with ethnic minorities. These data are essential to guide future multiethnic clinical trials on CCT-related ocular conditions such as glaucoma.

  4. Ethnic Variations in Central Corneal Thickness in a Rural Population in China: The Yunnan Minority Eye Studies.

    Pan, Chen-Wei; Li, Jun; Zhong, Hua; Shen, Wei; Niu, Zhiqiang; Yuan, Yuansheng; Chen, Qin

    2015-01-01

    To describe the ethnic differences in central corneal thickness (CCT) in population-based samples of ethnic Bai, Yi and Han people living in rural China. 6504 adults (2119 ethnic Bai, 2202 ethnic Yi and 2183 ethnic Han) aged 50 years or older participated in the study. Each subject underwent standardized ocular examinations and interviewer-administered questionnaires for risk factor assessment. CCT was measured for both eyes using an ultrasound pachymeter. Regression and principal component analysis were performed to examine the relationship of ethnicity and other factors with CCT. The mean CCT readings were 536.4 ± 34.2 μm in ethnic Bai, 532.1 ± 32.1 μm in ethnic Yi and 529.6 ± 32.7 μm in ethnic Han adults (Pethnic groups. In multivariate linear regression models, increasing CCT was associated with younger age (Pethnicity, greater body mass index (PEthnicity contributed significantly to presence of thin cornea (60%; Pethnic groups. This study of more than 6500 multiethnic participants demonstrates significant ethnic variations in CCT, with Han ethnicity having the thinnest cornea compared with ethnic minorities. These data are essential to guide future multiethnic clinical trials on CCT-related ocular conditions such as glaucoma.

  5. Evaluation of the Endothelial Cell Density and the Central Corneal Thickness in Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma

    Bożydar T. Tomaszewski

    2014-01-01

    Full Text Available Purpose. Evaluation of central corneal thickness (CCT and endothelial cell density (ECD in patients with senile cataract and coexisting pseudoexfoliation (PEX syndrome with glaucoma (PEXG and without glaucoma using specular microscopy. Participants and Methods. The study included 122 patients (217 eyes. In this group of patients we identified 133 eyes with PEX syndrome (65 with glaucoma, 68 without glaucoma and 84 eyes without PEX syndrome. ECD and CCT were measured in each eye by specular microscopy. Results. ECD in eyes with PEX syndrome without glaucoma (2297 ± 359 cell/mm2 and in eyes with PEXG (2241 ± 363 cell/mm2 was lower than in the control group (2503 ± 262 cell/mm2 (P<0.001. CCT in eyes with PEXG (508.2 ± 32.6 μm was thinner than in eyes with PEX syndrome without glaucoma (529.7 ± 30.3 μm and control group (527.7 ± 29.4 μm (P<0.001. Conclusions. This research shows that in eyes with PEX syndrome, both with and without glaucoma, ECD was statistically significantly lower than in the control group. In patients with PEXG, CCT was statistically significantly thinner than in the PEX syndrome and control group.

  6. Common genetic variants near the Brittle Cornea Syndrome locus ZNF469 influence the blinding disease risk factor central corneal thickness.

    Yi Lu

    2010-05-01

    Full Text Available Central corneal thickness (CCT, one of the most highly heritable human traits (h(2 typically>0.9, is important for the diagnosis of glaucoma and a potential risk factor for glaucoma susceptibility. We conducted genome-wide association studies in five cohorts from Australia and the United Kingdom (total N = 5058. Three cohorts were based on individually genotyped twin collections, with the remaining two cohorts genotyped on pooled samples from singletons with extreme trait values. The pooled sample findings were validated by individual genotyping the pooled samples together with additional samples also within extreme quantiles. We describe methods for efficient combined analysis of the results from these different study designs. We have identified and replicated quantitative trait loci on chromosomes 13 and 16 for association with CCT. The locus on chromosome 13 (nearest gene FOXO1 had an overall meta-analysis p-value for all the individually genotyped samples of 4.6x10(-10. The locus on chromosome 16 was associated with CCT with p = 8.95x10(-11. The nearest gene to the associated chromosome 16 SNPs was ZNF469, a locus recently implicated in Brittle Cornea Syndrome (BCS, a very rare disorder characterized by abnormal thin corneas. Our findings suggest that in addition to rare variants in ZNF469 underlying CCT variation in BCS patients, more common variants near this gene may contribute to CCT variation in the general population.

  7. Effects of artificial tear treatment on corneal epithelial thickness and corneal topography findings in dry eye patients.

    Çakır, B; Doğan, E; Çelik, E; Babashli, T; Uçak, T; Alagöz, G

    2018-05-01

    To investigate the effects of artificial tear treatment on central corneal epithelial thickness, and central, mid-peripheral and peripheral corneal thicknesses in patients with dry eye disease (DED). Patients with DED underwent ocular examinations, including Schirmer-2 test, slit lamp examination for tear break-up time (BUT), corneal topography (CT) for measuring mean central, mid-peripheral and peripheral corneal thickness values and anterior segment optic coherence tomography (AS-OCT) for obtaining central corneal epithelial thickness. After artificial tear treatment (carboxymethylcellulose and sodium hyaluronate formulations) for one month, patients were examined again at a second visit and the results were compared. Sixty-one eyes of 33 female dry eye patients (mean age: 38.3±5.7 years) were enrolled. The mean follow-up time was 36.4±3.3 days. The mean tear BUT and Schirmer-1 tests revealed significant improvement after treatment (P=0.000, P=0.000, respectively). Central corneal epithelium and mean mid-peripheral corneal thicknesses measured significantly higher after treatment (P=0.001, P=0.02). Changes in central and peripheral corneal thicknesses were not statistically significant. Artificial tear treatment in dry eye patients seems to increase central corneal epithelial and mid-peripheral corneal thicknesses. Measurement of corneal epithelial thickness can be a useful tool for evaluation of treatment response in dry eye patients. Further long-term prospective studies are needed to investigate this item. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  8. Comparison of central corneal thickness and endothelial cell measurements by Scheimpflug camera system and two noncontact specular microscopes.

    Karaca, Irmak; Yilmaz, Suzan Guven; Palamar, Melis; Ates, Halil

    2017-07-03

    To investigate the correlation of Scheimpflug camera system and two noncontact specular microscopes in terms of central corneal thickness (CCT) and corneal endothelial cell morphology measurements. One hundred eyes of 50 healthy subjects were examined by Pentacam Scheimpflug Analyzer, CEM-530 (Nidek Co, Ltd, Gamagori, Japan) and CellChek XL (Konan Medical, California, USA) via fully automated image analysis with no corrections made. Measurement differences and agreement between instruments were determined by intraclass correlation analysis. The mean age of the subjects was 36.74 ± 8.59 (range 22-57). CCTs were well correlated among all devices, with having CEM-530 the thinnest and CellChek XL the thickest measurements (intraclass correlation coefficient (ICC) = 0.83; p < 0.001 and ICC = 0.78; p < 0.001, respectively). Mean endothelial cell density (ECD) given by CEM-530 was lower than CellChek XL (2613.17 ± 228.62 and 2862.72 ± 170.42 cells/mm 2 , respectively; ICC = 0.43; p < 0.001). Mean value for coefficient of variation (CV) was 28.57 ± 3.61 in CEM-530 and 30.30 ± 3.53 in CellChek XL. Cell hexagonality (HEX) with CEM-530 was higher than with CellChek XL (68.70 ± 4.16% and 45.19 ± 6.58%, respectively). ECDs with CellChek XL and CEM-530 have good correlation, but the values obtained by CellChek XL are higher than CEM-530. Measurements for HEX and CV differ significantly and show weak correlation. Thus, we do not recommend interchangeable use of CellChek XL and CEM-530. In terms of CCTs, Pentacam, CEM-530 and CellChek XL specular microscopy instruments are reliable devices.

  9. Distribution of central corneal thickness and its association with ocular parameters in a large central European cohort: the Gutenberg health study.

    Esther M Hoffmann

    Full Text Available MAIN OBJECTIVE: To evaluate the distribution of central corneal thickness (CCT in a large German cohort and to analyse its relationship with intraocular pressure and further ocular factors. DESIGN: Population-based, prospective, cohort study. METHODS: The Gutenberg Health Study (GHS cohort included 4,698 eligible enrollees of 5,000 subjects (age range 35-74 years who participated in the survey from 2007 to 2008. All participants underwent an ophthalmological examination including slitlamp biomicroscopy, intraocular pressure measurement, central corneal thickness measurement, fundus examination, and were given a questionnaire regarding glaucoma history. Furthermore, all subjects underwent fundus photography and visual field testing using frequency doubling perimetry. RESULTS: Mean CCT was 557.3 ± 34.3 µm (male and 551.6±35.2 µm in female subjects (Mean CCT from right and left eyes. Younger male participants (35-44 years presented slightly thicker CCT than those older. We noted a significant CCT difference of 4 µm between right and left eyes, but a high correlation between eyes (Wilcoxon test for related samples: p<0.0001. Univariable linear regression stratified by gender showed that IOP was correlated with CCT (p<0.0001. A 10 µm increase in CCT led to an increase in IOP between 0.35-0.38 mm Hg, depending on the eye and gender. Multivariable linear regression analysis revealed correlations between gender, spherical equivalent (right eyes, and CCT (p<.0001 and p=0.03, respectively. CONCLUSIONS: We observed positive correlations between CCT and IOP and gender. CCT was not correlated with age, contact lens wear, positive family history for glaucoma, lens status, or iris colour.

  10. COMPARISON OF INTRAOCULAR PRESSURE MEASUREMENT WITH NON-CONTACT TONOMETRY AND APPLANATION TONOMETRY AMONG VARIOUS CENTRAL CORNEAL THICKNESS GROUPS

    Radhakrishnan B

    2018-02-01

    Full Text Available BACKGROUND Glaucoma is the second leading cause of blindness worldwide. Intraocular Pressure (IOP is the only known modifiable risk factor that has been shown to delay progression in both ocular hypertension and glaucoma patients. Clinical measurement of IOP has undergone several technical advances from the initial digital tension measurements, through indentation tonometry, to applanation tonometry and non-contact tonometry. This study was done to compare the intraocular pressure (IOP measurements with Non Contact Tonometry (NCT and Goldmann Applanation tonometry (GAT and to compare NCT IOP and GAT IOP among various central corneal thickness (CCT groups. MATERIALS AND METHODS IOP measurements were done by NCT and then by GAT followed by CCT. All IOP readings were taken in the sitting position over fifteen minutes. NCT was performed before the GAT to avoid the known mild reduction of IOP by anterior chamber compression with GAT. RESULTS The study included 200 eyes of 100 patients. Mean age of the patients was 58.14 ± 11.7 years (range 35- 81 years. The study population consisted of 58 males and 42 females. The mean ± SD intraocular pressure measurements were 23.39 ± 4.6 mmHg and 22.41 ± 5.9 mmHg for NCT and GAT, respectively. The difference between the NCT and GAT IOP was 0.98 ± 4.7 mm Hg. Mean CCT of the study group was 545.74 ± 38.23 microns. The IOP measured with both GAT and NCT showed no significant change with increasing CCT. The difference between the means increases with increasing CCT upto 600 microns. At lower IOPs ≤ 20 mm Hg, GAT measures are higher than NCT and this relationship is reversed at high IOPs. CONCLUSION Intraocular pressure measurement by NCT was consistently higher than GAT. There was a tendency for NCT to underestimate IOP at lower ranges and overestimates IOP at higher ranges. By applying appropriate correction factor for CCT, Noncontact tonometry could be used as a good screening tool for glaucoma evaluation.

  11. Comparison of central corneal thickness with four noncontact devices: An agreement analysis of swept-source technology

    Erhan Ozyol

    2017-01-01

    Full Text Available Purpose: The purpose of this study was to compare the central corneal thickness (CCT measurements of four noncontact devices in healthy eyes. Materials and Methods: In a sample of 45 healthy controls, CCT was measured using an optical biometer (IOLMaster 700 based on swept-source optical coherence tomography (SS-OCT, high-resolution rotating Scheimpflug camera system (Pentacam HR, spectral-domain OCT (SD-OCT device with an anterior segment module (Spectralis, and noncontact pachymetry (NCP device (Topcon TRK-2P. Agreement among the devices was analyzed using mean differences (i.e., bias and Bland–Altman analysis with 95% limits of agreement (LoA. Results: Mean CCT measurements were 537.5 ± 47.5 μm for SS-OCT optical biometer, 532.3 ± 43.8 μm for Scheimpflug system, 521.3 ± 44.7 μm for SD-OCT device, and 518.0 ± 43.1 μm for NCP (P < 0.001. The SD-OCT device and NCP showed the closest agreement, with a bias of 2.6 μm (95% LoA, −3.6–8.8 μm, whereas the SS-OCT optical biometer and NCP showed the least agreement, with a bias of 18.7 μm (95% LoA, −2.1–39.5 μm. Bias was 16.1 μm (95% LoA, −3.1–35.3 μm for SS-OCT optical biometer and SD-OCT, 5.1 μm (95% LoA, −6.8–17.0 μm for SS-OCT optical biometer and Scheimpflug system, 10.9 μm (95% LoA, −15.1–36.9 μm for SD-OCT device and Scheimpflug system, and 13.6 μm (95% LoA, −5–32.2 μm for Scheimpflug system and NCP. Conclusions: SS-OCT optical biometer overestimates CCT measurements compared to Scheimpflug system, SD-OCT device, and NCP. Given mean differences and range variations in CCT measurements between devices, SS-OCT optical biometer and Scheimpflug system are interchangeable as are SD-OCT and NCP.

  12. Comparison of central corneal thickness with four noncontact devices: An agreement analysis of swept-source technology.

    Ozyol, Erhan; Özyol, Pelin

    2017-06-01

    The purpose of this study was to compare the central corneal thickness (CCT) measurements of four noncontact devices in healthy eyes. In a sample of 45 healthy controls, CCT was measured using an optical biometer (IOLMaster 700) based on swept-source optical coherence tomography (SS-OCT), high-resolution rotating Scheimpflug camera system (Pentacam HR), spectral-domain OCT (SD-OCT) device with an anterior segment module (Spectralis), and noncontact pachymetry (NCP) device (Topcon TRK-2P). Agreement among the devices was analyzed using mean differences (i.e., bias) and Bland-Altman analysis with 95% limits of agreement (LoA). Mean CCT measurements were 537.5 ± 47.5 μm for SS-OCT optical biometer, 532.3 ± 43.8 μm for Scheimpflug system, 521.3 ± 44.7 μm for SD-OCT device, and 518.0 ± 43.1 μm for NCP (P < 0.001). The SD-OCT device and NCP showed the closest agreement, with a bias of 2.6 μm (95% LoA, -3.6-8.8 μm), whereas the SS-OCT optical biometer and NCP showed the least agreement, with a bias of 18.7 μm (95% LoA, -2.1-39.5 μm). Bias was 16.1 μm (95% LoA, -3.1-35.3 μm) for SS-OCT optical biometer and SD-OCT, 5.1 μm (95% LoA, -6.8-17.0 μm) for SS-OCT optical biometer and Scheimpflug system, 10.9 μm (95% LoA, -15.1-36.9 μm) for SD-OCT device and Scheimpflug system, and 13.6 μm (95% LoA, -5-32.2 μm) for Scheimpflug system and NCP. SS-OCT optical biometer overestimates CCT measurements compared to Scheimpflug system, SD-OCT device, and NCP. Given mean differences and range variations in CCT measurements between devices, SS-OCT optical biometer and Scheimpflug system are interchangeable as are SD-OCT and NCP.

  13. Intraocular pressure, corneal thickness, and corneal hysteresis in Steinert's myotonic dystrophy

    Carlos Alexandre de A. Garcia Filho

    2011-06-01

    Full Text Available PURPOSE: Low intraocular pressure (IOP measured by Goldmann applanation tonometry (GAT is one of the ocular manifestations of Steinert's myotonic dystrophy. The goal of this study was to evaluate the corneal-compensated IOP as well as corneal properties (central corneal thickness and corneal hysteresis in patients with myotonic dystrophy. METHODS: A total of 12 eyes of 6 patients with Steinert's myotonic dystrophy (dystrophy group and 12 eyes of 6 age-, race-, and gender-matched healthy volunteers (control group were included in the study. GAT, Dynamic Contour Tonometry (DCT-Pascal and Ocular Response Analyzer (ORA were used to assess the IOP. Central corneal thickness was obtained by ultrasound pachymetry, and corneal hysteresis was analyzed using the ORA device. In light of the multiplicity of tests performed, the significance level was set at 0.01 rather than 0.05. RESULTS: The mean (standard deviation [SD] GAT, DCT, and corneal-compensated ORA IOP in the dystrophy group were 5.4 (1.4 mmHg, 9.7 (1.5 mmHg, and 10.1 (2.6 mmHg, respectively. The mean (SD GAT, DCT, and corneal-compensated ORA IOP in the control group was 12.6 (2.9 mmHg, 15.5 (2.7 mmHg, and 15.8 (3.4 mmHg, respectively. There were significant differences in IOP values between dystrophy and control groups obtained by GAT (mean, -7.2 mmHg; 99% confidence interval [CI], -10.5 to -3.9 mmHg; P<0.001, DCT (mean, -5.9 mmHg; 99% CI, -8.9 to -2.8 mmHg; P<0.001, and corneal-compensated ORA measurements (mean, -5.7 mmHg; 99% CI, -10.4 to -1.0 mmHg; P=0.003. The mean (SD central corneal thickness was similar in the dystrophy (542 [31] µm and control (537 [11] µm groups (P=0.65. The mean (SD corneal hysteresis in the dystrophy and control groups were 11.2 (1.5 mmHg and 9.7 (1.2 mmHg, respectively (P=0.04. CONCLUSIONS: Patients with Steinert's myotonic dystrophy showed lower Goldmann and corneal-compensated IOP in comparison with healthy individuals. Since central corneal thickness and

  14. A comparative study of central corneal thickness (CCT) and intraocular pressure (IOP) in University of KwaZulu-Natal students of Black and Indian ethnicity*

    Z. Sardiwalla; D. Moodley; T. Ndawonde; A. Madikizela; N. Ngobese; N. Thobela

    2012-01-01

    Thisstudy compared central corneal thickness (CCT) and intraocular pressure (IOP) of Black and Indian students from the University of Kwa-Zulu-Natal. Two hundred (100 Black and 100 Indi- an) participants of both genders aged 18-25 years (mean and standard deviation; 20.1±1.6 years) participated in this study. CCT and IOP were measured for the right eye of each participant using a Tono-Pachymeter (NT530P) and a Goldmann applanation tonometer (GAT) respectively. Data was analyzed with descr...

  15. Comparing two acromegalic patients with respect to central corneal thickness, intraocular pressure, and tear insulin-like growth factor levels before and after treatment

    Kan Emrah

    2015-01-01

    Full Text Available The aim of the study was to compare the central corneal thickness (CCT, intraocular pressure (IOP, and tear insulin-like growth factor-1 (IGF-1 levels of 2 patients with acromegaly before and after the surgical treatment of the disease. CCTs, IOP levels, and tear IGF-1 values showed a decrease after the treatment in 2 patients. As we found higher CCT, IOP, and tear IGF-1 levels in the active phase of the disease in two acromegaly patients, detailed information about the activity of the disease may be important before the examination of these patients.

  16. Thick keratoconic cornea associated with posterior polymorphous corneal dystrophy.

    Zaarour, K; Slim, E; Antoun, J; Waked, N

    2017-03-01

    We herein report a case of bilateral unusually thick non-edematous keratoconic corneas with associated endothelial features of posterior polymorphous corneal dystrophy (PPCD). We report the case of a 27-year-old myopic woman who presented for refractive surgery. Slit lamp exam showed bilateral corneal protrusion with diffuse deep stromal and endothelial vesicular opacities and small paracentral bands. Topography showed generalized advanced corneal steepening in both eyes with increased anterior and posterior central corneal elevations in comparison to the best fit sphere. Ultrasound pachymetry showed central corneal thickness of 605μm (RE) and 612μm (LE). On specular biomicroscopy, cell density of 2503 cells/mm 2 RE and 1526 cells/mm 2 LE with significant cellular pleomorphism and polymegathism were noted. Clinical and paraclinical findings together suggest the presence of simultaneous keratoconus and PPCD. The literature has suggested an association between PPCD and steep cornea. Moreover, many reports have also described cases of associated PPCD and keratoconus with characteristic thinning and ectasia, in comparison to the unusual thick corneas noted in our patient, despite the absence of edema. Identification of genetics factors is further needed to clarify this association. This case describes a patient whose corneas present features of both keratoconus and PPCD and is unique due to the presence of increased corneal thickness despite the absence of edema. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Meta-analysis of Pentacam vs. ultrasound pachymetry in central corneal thickness measurement in normal, post-LASIK or PRK, and keratoconic or keratoconus-suspect eyes.

    Wu, Wenjing; Wang, Yan; Xu, Lulu

    2014-01-01

    The aim of this meta-analysis is to evaluate the central corneal thickness (CCT) measurement differences between Pentacam (Oculus Inc., Germany) and Ultrasound Pachymetry (USP) in normal (unoperated eyes , myopic and astigmatic eyes without corneal disease or topographic irregularity), after laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK), and keratoconic or keratoconus suspected eyes. We assess whether Pentacam and USP have similar CCT differences in normal, thinner corneas after LASIK or PRK procedures, and kerotoconic or keratoconus suspected eyes. Data sources, including PubMed, Medline, EMBASE, and Cochrane Central Registry of Controlled Trials on the Cochrane Library, were searched to find the relevant studies. Primary outcome measures were CCT measurement between Pentacam and USP. Three groups of eyes were analyzed: normal; LASIK or PRK eyes; and keratoconus suspected or keratoconic eyes. Nineteen studies describing 1,908 eyes were enrolled in the normal group. Pentacam results were 1.47 μm ,95 % confidence interval (CI) -2.32 to 5.27, higher than USP without statistically significant difference (P = 0.45). Nine studies with total 539 eyes were included in the corneas after LASIK or PRK. The mean difference in the CCT measurement with Pentacam and ultrasound pachymetry was 1.03 μm, with the 95 % CI -3.36 to 5.42, there was no statistically difference (P = 0.64). Four studies with a total of 185 eyes were included in the keratoconic eyes or keratoconus-suspect group, however,the mean difference was -6.33 μm (95 % CI -9.17 to-3.49), which was statistically different between Pentacam and ultrasound pachymetry in the CCT measurement (P LASIK or PRK procedures. However, in keratoconic or keratoconus-suspect eyes, Pentacam slightly underestimates the central corneal thickness than does ultrasound pachymetry, which may result from the difficulty in fixation of keratoconic eyes, misalignment of Pentacam and the variation

  18. Reproducibility of the measurement of central corneal thickness in healthy subjects obtained with the optical low coherence reflectometry pachymeter and comparison with the ultrasonic pachymetry.

    Garza-Leon, Manuel; Plancarte-Lozano, Eduardo; Valle-Penella, Agustín Del; Guzmán-Martínez, María de Lourdes; Villarreal-González, Andrés

    2018-01-01

    Corneal pachymetry is widely used for refractive surgery and follow up in keratoconus, accurate measurement is essential for a safe surgery. To assess intraobserver reliability of central corneal thickness (CCT) measurements using optical low-coherence reflectometry (OLCR) technology and its agreement with ultrasonic pachymeter (US). Randomized and prospective comparative evaluation of diagnostic technology. One randomly healthy eye of subjects was scanned three times with both devices. Intraobserver within-subject standard deviation (Sw), coefficient of variation (CVw) and intraclass correlation coefficient (ICC) were obtained for reliability analysis; for study agreement, data were analyzed using the paired-sample t test and the Bland-Altman LoA method. The mean of three scans of each equipment was used to assess the LoA. The study enrolled 30 eyes of 30 subjects with average age of 28.70 ± 8.06 years. For repeatability, the Sw were 3.41 and 5.96 µ, the intraobserver CVw was 2 and 4% and ICC 0.991 and 0.988, for OLCR and US respectively. The mean CCT difference between OLCR and US was 8.90 ± 9.03 µ (95% confidence interval: 5.52-2.27 µ), and the LoA was 35.40 µ. OLCR technology provided reliable intraobserver CCT measurements. Both pachymetry measurements may be used interchangeably with minimum calibration adjustment. Copyright: © 2018 Permanyer.

  19. Assessment of corneal epithelial thickness in dry eye patients.

    Cui, Xinhan; Hong, Jiaxu; Wang, Fei; Deng, Sophie X; Yang, Yujing; Zhu, Xiaoyu; Wu, Dan; Zhao, Yujin; Xu, Jianjiang

    2014-12-01

    To investigate the features of corneal epithelial thickness topography with Fourier-domain optical coherence tomography (OCT) in dry eye patients. In this cross-sectional study, 100 symptomatic dry eye patients and 35 normal subjects were enrolled. All participants answered the ocular surface disease index questionnaire and were subjected to OCT, corneal fluorescein staining, tear breakup time, Schirmer 1 test without anesthetic (S1t), and meibomian morphology. Several epithelium statistics for each eye, including central, superior, inferior, minimum, maximum, minimum - maximum, and map standard deviation, were averaged. Correlations of epithelial thickness with the symptoms of dry eye were calculated. The mean (±SD) central, superior, and inferior corneal epithelial thickness was 53.57 (±3.31) μm, 52.00 (±3.39) μm, and 53.03 (±3.67) μm in normal eyes and 52.71 (±2.83) μm, 50.58 (±3.44) μm, and 52.53 (±3.36) μm in dry eyes, respectively. The superior corneal epithelium was thinner in dry eye patients compared with normal subjects (p = 0.037), whereas central and inferior epithelium were not statistically different. In the dry eye group, patients with higher severity grades had thinner superior (p = 0.017) and minimum (p dry eye corneal epithelium was thinner than normal eyes in the superior region. In more severe dry eye disease patients, the superior and minimum epithelium was much thinner, with a greater range of map standard deviation.

  20. Evaluation of intraocular pressure according to corneal thickness before and after excimer laser corneal ablation for myopia.

    Hamed-Azzam, Shirin; Briscoe, Daniel; Tomkins, Oren; Shehedeh-Mashor, Raneen; Garzozi, Hanna

    2013-08-01

    Intraocular pressure is affected by corneal thickness and biomechanics. Following ablative corneal refractive surgery, corneal structural changes occur. The purpose of the study is to determine the relationship between the mean central corneal thickness (CCT) and the change in intraocular pressure measurements following various corneal ablation techniques, using different measurement methods. Two hundred myopic eyes undergoing laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) were enrolled into a prospective, non-randomized study. Corneal parameters examined included full ocular examination, measurement of CCT, corneal topography, corneal curvature and ocular refractivity. Intraocular pressure measurements were obtained using three different instruments-non-contact tonometer, Goldmann applanation tonometer and TonoPen XL (TonoPen-Central and TonoPen-Peripheral). All measurements were performed pre-operatively and 4 months post-operatively. Post-operative intraocular pressure was significantly lower than pre-operative values, with all instruments (p value tonometer and non-contact tonometer (p value < 0.001, ANOVA). Intraocular pressure readings are significantly reduced following corneal ablation surgery. We determined in our myopic patient cohort that the TonoPen XL intraocular pressure measurement method is the least affected following PRK and LASIK as compared to other techniques.

  1. Effect of central corneal thickness on intraocular pressure and comparison of Topcon CT-80 non-contact tonometry with Goldmann applanation tonometry.

    Mansoori, Tarannum; Balakrishna, Nagalla

    2018-03-01

    To compare intraocular pressure (IOP) measurements obtained with the Topcon CT-80 non-contact tonometer (NCT) and Goldmann applanation tonometer (GAT), in different ranges of IOP in normal and glaucoma subjects, and to assess the influence of central corneal thickness (CCT) on the IOP measurements in Asian Indian eyes. Four hundred and two eyes of 402 subjects (193 newly diagnosed primary open angle glaucoma [POAG] and 209 normal) were enrolled for this prospective study. For each eye, IOP was measured with GAT by a glaucoma specialist and NCT by a trained optometrist. The IOP values were compared among the tonometers in the three different IOP ranges (≤ 12 mmHg, 13-20 mmHg and ≥ 21 mmHg) using Bland-Altman graphs. Correlation between GAT and NCT was assessed by Pearson correlation co-efficient. CCT was measured with ultrasound pachymetry and its correlation with GAT and NCT was analysed using linear regression analysis. The mean paired difference of IOP between NCT and GAT was 1.556 ± 2.69 mmHg (r = 0.26, p = 0.006) at IOP range of ≤ 12 mmHg, -1.665 ± 2.6 mmHg (r = 0.51, p tonometer and that the IOP readings obtained with these tonometers are not interchangeable. © 2017 Optometry Australia.

  2. Corneal Biomechanical Properties after FS-LASIK with Residual Bed Thickness Less Than 50% of the Original Corneal Thickness

    Haixia Zhang

    2018-01-01

    Full Text Available Background. The changes in corneal biomechanical properties after LASIK remain an unknown but important topic for surgical design and prognostic evaluation. This study aims to observe the postoperative corneal biomechanical properties one month after LASIK with amount of corneal cutting (ACC greater than 50% of the central corneal thickness (CCT. Methods. FS-LASIK was performed in 10 left rabbit eyes with ACC being 60% (L60 and 65% (L65 of the CCT, while the right eyes (R were the control. After 4 weeks, rabbits were executed and corneal strip samples were prepared for uniaxial tensile tests. Results. At the same strain, the stresses of L65 and L60 were larger than those of R. The elastic moduli of L60 and L65 were larger than those of R when the stress was 0.02 MPa, while they began to be less than those of R when stress exceeds the low-stress region. After 10 s relaxation, the stress of specimens L65, L60, and R increased in turn. Conclusion. The elastic moduli of the cornea after FS-LASIK with ACC greater than 50% of the CCT do not become less under normal rabbit IOP. The limit stress grows with the rise of ACC when relaxation becomes stable.

  3. Central corneal thickness, intraocular pressure, and degree of myopia in an adult myopic population aged 20 to 40 years in southeast Spain: determination and relationships

    Manuel Garcia-Medina

    2011-02-01

    Full Text Available Manuel Garcia-Medina1, Jose Javier Garcia-Medina2,3, Pablo Garrido-Fernandez1, Jose Galvan-Espinosa1, Jesus Martin-Molina1, Carlos Garcia-Maturana4, Sergio Perez-Pardo1, Maria Dolores Pinazo-Duran3 1Department of Ophthalmology, Torrecardenas Hospital, Almeria, Spain; 2Department of Ophthalmology, Huercal Overa Hospital, Almeria, Spain; 3Ophthalmology Research Unit “Santiago Grisolia”, University Hospital Doctor Peset, Valencia, Spain; 4University of Sevilla, SpainObjective: To determine the values of, and study the relationships among, central corneal thickness (CCT, intraocular pressure (IOP, and degree of myopia (DM in an adult myopic population aged 20 to 40 years in Almeria (southeast Spain. To our knowledge this is first study of this kind in this region.Methods: An observational, descriptive, cross-sectional study was done in which a sample of 310 myopic patients (620 eyes aged 20 to 40 years was selected by gender- and age-stratified sampling, which was proportionally fixed to the size of the population strata for which a 20% prevalence of myopia, 5% epsilon, and a 95% confidence interval were hypothesized. We studied IOP, CCT, and DM and their relationships by calculating the mean, standard deviation, 95% confidence interval for the mean, median, Fisher’s asymmetry coefficient, range (maximum, minimum, and the Brown-Forsythe’s robust test for each variable (IOP, CCT, and DM.Results: In the adult myopic population of Almeria aged 20 to 40 years (mean of 29.8, the mean overall CCT was 550.12 µm. The corneas of men were thicker than those of women (P = 0.014. CCT was stable as no significant differences were seen in the 20- to 40-year-old subjects’ CCT values. The mean overall IOP was 13.60 mmHg. Men had a higher IOP than women (P = 0.002. Subjects over 30 years (13.83 had a higher IOP than those under 30 (13.38 (P = 0.04. The mean overall DM was -4.18 diopters. Men had less myopia than women (P < 0.001. Myopia was stable in the

  4. The influence of central corneal thickness and age on intraocular pressure measured by pneumotonometry, non-contact tonometry, the Tono-Pen XL, and Goldmann applanation tonometry.

    Tonnu, P-A; Ho, T; Newson, T; El Sheikh, A; Sharma, K; White, E; Bunce, C; Garway-Heath, D

    2005-07-01

    To evaluate the influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurements made with the Goldmann applanation tonometer (GAT), Tono-Pen XL, ocular blood flow tonograph (OBF), and Canon TX-10 non-contact tonometer (NCT). CCT was recorded for either eye (randomly selected) of each of 105 untreated patients with ocular hypertension and glaucoma attending the glaucoma research unit at Moorfields Eye Hospital. For each of the selected eyes, IOP was measured with the GAT (two observers), Tono-Pen, OBF, and NCT in a randomised order. The relation of measured IOP and of inter-tonometer differences with CCT and subject age was explored by linear regression analysis. A significant association between measured IOP and CCT was found with each instrument. The change in measured IOP for a 10 mum increase in CCT was 0.28, 0.31, 0.38, and 0.46 for the GAT, Tono-Pen, OBF, and NCT, respectively (all p< or = 0.05). There was a significant association between the NCT/GAT differences and CCT, with a tendency of NCT to overestimate GAT in eyes with thicker corneas. There was a significant association between GAT/Tono-Pen and OBF/Tono-Pen differences and age, with a tendency of GAT and OBF to overestimate the Tono-Pen in eyes of older subjects. IOP measurement by all four methods is affected by CCT. The NCT is affected by CCT significantly more than the GAT. Subject age has a differential effect on the IOP measurements made by the GAT and OBF compared to the Tono-Pen.

  5. Comparison between a New Optical Biometry Device and an Anterior Segment Optical Coherence Tomographer for Measuring Central Corneal Thickness and Anterior Chamber Depth

    Jinhai Huang

    2016-01-01

    Full Text Available Purpose. To compare between a new optical biometer (AL-Scan, Nidek Co., Aichi, Japan and an anterior segment optical coherence tomographer (Visante AS-OCT, Carl Zeiss Meditec, Dublin, USA for measuring central corneal thickness (CCT, anterior chamber depth (ACD, and aqueous depth (AD. Methods. Sixty-three eyes of 63 normal subjects were examined with AL-Scan and Visante AS-OCT in this prospective study. One eye per subject was measured three times with both devices to record their CCT, ACD, and AD. All procedures were performed by the same operator. Agreement between the two devices was assessed using paired t-tests, Bland-Altman plots, and 95% limits of agreement (LoA. Results. The mean CCT, ACD, and AD measured by AL-Scan were 538.59±27.37 μm, 3.70±0.30 mm, and 3.16±0.30 mm, respectively. The mean values obtained by the Visante OCT were 536.14±26.61 μm for CCT, 3.71±0.29 mm for ACD, and 3.17±0.29 mm for AD. The mean CCT by the AL-Scan was higher than that obtained by the Visante AS-OCT (difference = 2.45±6.07 μm, P<0.05. The differences in ACD and AD measurements were not statistically significant. The 95% LoA of CCT, ACD, and AD were between −9.44 and 14.35 μm, −0.15 and 0.12 mm, and −0.15 and 0.12 mm, respectively. Conclusions. Since these two devices were comparable for measuring CCT, ACD, and AD, their results can be interchangeably used in the clinic.

  6. Genome-wide analysis of central corneal thickness in primary open-angle glaucoma cases in the NEIGHBOR and GLAUGEN consortia.

    Ulmer, Megan; Li, Jun; Yaspan, Brian L; Ozel, Ayse Bilge; Richards, Julia E; Moroi, Sayoko E; Hawthorne, Felicia; Budenz, Donald L; Friedman, David S; Gaasterland, Douglas; Haines, Jonathan; Kang, Jae H; Lee, Richard; Lichter, Paul; Liu, Yutao; Pasquale, Louis R; Pericak-Vance, Margaret; Realini, Anthony; Schuman, Joel S; Singh, Kuldev; Vollrath, Douglas; Weinreb, Robert; Wollstein, Gadi; Zack, Donald J; Zhang, Kang; Young, Terri; Allingham, R Rand; Wiggs, Janey L; Ashley-Koch, Allison; Hauser, Michael A

    2012-07-03

    To investigate the effects of central corneal thickness (CCT)-associated variants on primary open-angle glaucoma (POAG) risk using single nucleotide polymorphisms (SNP) data from the Glaucoma Genes and Environment (GLAUGEN) and National Eye Institute (NEI) Glaucoma Human Genetics Collaboration (NEIGHBOR) consortia. A replication analysis of previously reported CCT SNPs was performed in a CCT dataset (n = 1117) and these SNPs were then tested for association with POAG using a larger POAG dataset (n = 6470). Then a CCT genome-wide association study (GWAS) was performed. Top SNPs from this analysis were selected and tested for association with POAG. cDNA libraries from fetal and adult brain and ocular tissue samples were generated and used for candidate gene expression analysis. Association with one of 20 previously published CCT SNPs was replicated: rs12447690, near the ZNF469 gene (P = 0.001; β = -5.08 μm/allele). None of these SNPs were significantly associated with POAG. In the CCT GWAS, no SNPs reached genome-wide significance. After testing 50 candidate SNPs for association with POAG, one SNP was identified, rs7481514 within the neurotrimin (NTM) gene, that was significantly associated with POAG in a low-tension subset (P = 0.00099; Odds Ratio [OR] = 1.28). Additionally, SNPs in the CNTNAP4 gene showed suggestive association with POAG (top SNP = rs1428758; P = 0.018; OR = 0.84). NTM and CNTNAP4 were shown to be expressed in ocular tissues. The results suggest previously reported CCT loci are not significantly associated with POAG susceptibility. By performing a quantitative analysis of CCT and a subsequent analysis of POAG, SNPs in two cell adhesion molecules, NTM and CNTNAP4, were identified and may increase POAG susceptibility in a subset of cases.

  7. Evaluación del espesor corneal central y su influencia en la presión intraocular en pacientes del Hospital "Dr. Miguel Enríquez" Evaluation of the central corneal thickness and its impact on the intraocular pressure of patients in "Dr. Miguel Enriquez" hospital

    María Teresa Arrronte Alarcón

    2012-01-01

    Full Text Available Objetivo: evaluar el espesor corneal central en sujetos sanos, hipertensos oculares, sospechosos de glaucoma y glaucomatosos, y su influencia en la presión intraocular. Métodos: se realizó un estudio descriptivo y transversal que incluyó 708 ojos de 356 sujetos que acudieron al servicio de oftalmología del Hospital Universitario "Dr. Miguel Enríquez" entre enero y diciembre de 2010. A los pacientes se les midió el espesor corneal central con paquimetría ultrasónica (paquímetro US 4000. El resto de la información se obtuvo a partir de las historias clínicas de los pacientes. Resultados: Los hipertensos oculares presentaron córneas gruesas (p=0,07; el mayor número de casos que tenían diagnóstico de sospecha de glaucoma y de glaucoma primario de ángulo abierto presentaron un grosor corneal delgado (p=0,62 y p=0,08 respectivamente. Si no se hubiese tenido en cuenta el factor de corrección para evaluar la presión intraocular se encontraría 48,1 % de los glaucomatosos y 31,5 % de los hipertensos oculares con diagnóstico inadecuado (pObjective: to evaluate the central corneal thickness in healthy individuals, in persons with ocular hypertension, and in suspected glaucoma and glaucomatous people, and its influence in intraocular pressure. Methods: a cross-sectional and descriptive study was performed in 708 eyes from 356 people who had been seen at ophthalmology service of “Dr. Miguel Enríquez”, university hospital from January to December, 2010. Their central corneal thickness was measured with ultrasonic pachymetry (pachymeter US 4000. The rest of the information came from the clinical histories of the patients. Results: Most of the ocular hypertensives presented thick corneas (p=0,07; a high number of cases that had diagnosis of glaucoma suspicion and primary open-angle glaucoma showed thin corneas (p=0,62 and (p=0,08 respectively. If the correction factor to evaluate the IOP had not been considered, then 48,1 % of the

  8. Confiabilidade das medidas de espessura central da córnea com Orbscan II e paquímetro ultra-sônico Reliability of corneal thickness measurements by Orbscan II and ultrasound pachymeter

    Adamo Lui Netto

    2005-02-01

    Full Text Available OBJETIVO: Avaliar a confiabilidade das medidas de espessura central de córnea comparando o Orbscan II com o paquímetro ultra-sônico. MÉTODOS: Foi realizado estudo retrospectivo de 134 olhos, por meio do levantamento de prontuários de 67 pacientes avaliados entre o período de janeiro a junho de 2001. Foram avaliados o sexo, idade, acuidade visual com a melhor correção, refração e medidas de espessura central corneal pelo paquímetro ultra-sônico e Orbscan II. Os dados paquimétricos foram submetidos à análise do teste t pareado e as diferenças consideradas significativas se pPURPOSE: To access the reliability of corneal thickness measurements by Orbscan II and ultrasound pachymeter. METHODS: A retrospective study of 134 eyes from 67 normal subjects between January and June 2001 was obtained. Sex, age, visual acuity, refractive error and corneal thickness measurements by Orbscan II and ultrasound pachymetry were evaluated. All results were analyzed by the paired t test (p<0.05. RESULTS: Sixty-seven subjects, 34 (50.7% female and 33 (49.3% male, with a mean age of 32.44±9.98 were evaluated. The mean of spherical equivalent was -2.68±2.62. The mean corneal thickness was 534.81±34.45 with the Orbscan II system and 535.00±29.53 with the ultrasound pachymeter, values that were not significantly different (p=0.8922. The correlation coefficient between both instruments was 0.8774, and it is effective. CONCLUSIONS: Both methods are similar showing good correlation. In this study, the Orbscan II showed reliability, and this tool is extremely useful to evaluate subjects regarding refractive surgery.

  9. A comparison of the Goldmann applanation and non-contact (Keeler Pulsair EasyEye) tonometers and the effect of central corneal thickness in indigenous African eyes.

    Babalola, O E; Kehinde, A V; Iloegbunam, A C; Akinbinu, T; Moghalu, C; Onuoha, I

    2009-03-01

    The Keeler Pulsair EasyEye non-contact tonometer (NCT) was introduced into practice at Rachel Eye Center Abuja, Nigeria, where the patients are indigenous Africans. This was compared to the 'gold standard' Goldmann applanation tonometer (GAT) to determine if the instrument was accurate in Africans, with particular reference to the influence of central corneal thickness (CCT). 174 eyes of 88 patients were analysed. Pachymetry was performed using Sonomed PacScan AP300, and GAT with the Haag Streit R-900. Pachymetric corrections of NCT (NCTc) and GAT (GATc) were carried out with the Sonomed algorithm. Pearson's correlation r, linear regression analysis, Student t-test and Bland-Altman analysis were used to compare the instruments. Mean NCT readings were similar (17.36 mmHg) to mean GAT (17.42 mmHg; p = 0.769). GAT/NCT correlation coefficient, r, was 0.883 as compared with 0.868 for GATc/NCTc. The linear regression equation was GAT = 2.79 + 0.84*NCT (r(2) = 0.78). Forty-five per cent of differences were within 1 mmHg, while 79% were within 3 mmHg. This was similar to findings in some studies on Caucasians. Bland-Altman analysis however suggested that the spread of differences was wider than in those studies. Outliers (differences more than 5 mmHg) sometimes reflected difficulties encountered with GAT in routine practice. Mean CCT was 537.9 microm, (S.D. 38.4, 95% confidence interval 532.1-543.7 microm) and CCT appeared lower than in Caucasians. Both GAT and NCT IOP tended to rise with increasing CCT but NCT had a greater tendency to do so. Regression analysis suggested that NCT IOP increased by 0.6 mmHg for every 10 mum increase in CCT, compared to 0.4 mmHg for GAT. Thirty-eight per cent of the patients preferred NCT as opposed to 25% GAT. The Keeler Pulsair EasyEye gives reliable measurements of IOP in African eyes but is significantly affected by CCT. Particularly in borderline cases where management decisions have to be taken, it may be necessary to have pachymetric

  10. A comparative study of central corneal thickness (CCT and intraocular pressure (IOP in University of KwaZulu-Natal students of Black and Indian ethnicity*

    Z. Sardiwalla

    2012-12-01

    Full Text Available Thisstudy compared central corneal thickness (CCT and intraocular pressure (IOP of Black and Indian students from the University of Kwa-Zulu-Natal. Two hundred (100 Black and 100 Indi- an participants of both genders aged 18-25 years (mean and standard deviation; 20.1±1.6 years participated in this study. CCT and IOP were measured for the right eye of each participant using a Tono-Pachymeter (NT530P and a Goldmann applanation tonometer (GAT respectively. Data was analyzed with descriptive, t-test and Pearson’s cor-relation statistics. In the total sample (N = 200, the mean CCT value was 519.5 ± 38.6 μm and CCT was higher in the Indians (526.5 ± 37.2 µm than in the Blacks (512.4 ± 38.9 µm (p = 0.01.  Also, it was higher in the females (522.3 µm than in males (516.7 µm, but the difference was insignificant (p = 0.07. The mean CCT was higher in the Indian males (520.1 µm than in the Black males (513.2 µm, but the difference was insignificant (p=0.39.  However, it was significantly higher in the Indian females (533 µm than in the Black females (511.6 µm (p = 0.003. In the total sample, the mean IOP was 14.6 mmHg and IOP was greater in Indiansthan Blacks (mean = 15.3 ± 2.9 mmHg and 13.8 ± 2.6 mmHg respectively (p = 0.01. Also, the mean IOP (N = 200 value was slightly higher in the females (14.7 mmHg than in males (14.5 mmHg (p = 0.51. The mean IOP was higher in the Indian males (15.0 mmHg than in the Black males (14.0 mmHg (p = 0.07 and the mean IOP value was higher in the Indian females (15.7 mmHg than in the Black females (13.6 mmHg (p < 0.001. The higher mean IOP value in the Indian than Black participants was attributed to the higher mean CCT values. A positive, but inconsistent association between CCT and IOP was found in this study, the coefficient in the total sample (r = 0.382, p = 0.000, in the Blacks (r = 0.196, p = 0.05 and in Indians (r = 0.498, p = 0.000. A national population study comparing CCT and IOP in the various

  11. Intraoperative corneal thickness measurements during corneal collagen cross-linking with isotonic riboflavin solution without dextran in corneal ectasia.

    Cınar, Yasin; Cingü, Abdullah Kürşat; Sahin, Alparslan; Türkcü, Fatih Mehmet; Yüksel, Harun; Caca, Ihsan

    2014-03-01

    Abstract Objective: To monitor the changes in corneal thickness during the corneal collagen cross-linking procedure by using isotonic riboflavin solution without dextran in ectatic corneal diseases. The corneal thickness measurements were obtained before epithelial removal, after epithelial removal, following the instillation of isotonic riboflavin solution without dextran for 30 min, and after 10 min of ultraviolet A irradiation. Eleven eyes of eleven patients with progressive keratoconus (n = 10) and iatrogenic corneal ectasia (n = 1) were included in this study. The mean thinnest pachymetric measurements were 391.82 ± 30.34 µm (320-434 µm) after de-epithelialization of the cornea, 435 ± 21.17 µm (402-472 µm) following 30 min instillation of isotonic riboflavin solution without dextran and 431.73 ± 20.64 µm (387-461 µm) following 10 min of ultraviolet A irradiation to the cornea. Performing corneal cross-linking procedure with isotonic riboflavin solution without dextran might not induce corneal thinning but a little swelling throughout the procedure.

  12. Evaluation of corneal thickness alterations during menstrual cycle in productive age women

    Negar Amiri Ghahfarokhi

    2015-01-01

    Full Text Available Purpose: To determine the change in corneal thickness through different phases of menstrual cycle in women who are in their productive age. Materials and Methods: Fifty healthy women with normal past medical history were enrolled in this prospective study. Central corneal thickness was measured with ultrasound pachymeter three times during a menstrual cycle: Beginning of the cycle (days 1-3, ovulation time, and at the end of cycle (days 27-32. We confirmed ovulation time with determining a peak in luteinizing hormone in urine. To avoid the diurnal variation of the corneal thickness which is well recognized, we checked all our subjects at 10 in the morning. Results: In days 1 to 3 of menstruation, mean corneal thickness was 541.40±11.36 and 540.82±11.70 microns for left and right eyes respectively. At ovulation time the mean thickness changed to 556.50±7.11 and 555.98±7.26 microns for left and right eyes respectively, and at the end of the cycle, the corneal thickness turned in to 536.38±12.83 and 535.48±13.08 microns for left and right eyes respectively. The difference of corneal thickness was statistically significant relating to the different stages of menstrual cycle. Conclusion: The thickest cornea during the menstruation cycle is achieved at the ovulation time and the thinnest at the end of the cycle and this should be taken in to account whilst plan to do a corneal refractive surgery.

  13. Correlation between Corneal Thickness and Degree of Myopic Refractory Error

    A Mortazavi

    2005-01-01

    Full Text Available Background: corneal thickness is an important factor in refractive surgeries such as Radial Keratotomy (RK, Photo Refractive Keratotomy (PRK and Laser Insitu Keratomileusis (LASIK. This study evaluated the correlation between this factor and the degree of myopic refractory error. Methods: In this cross-sectional study, 224 myopic eyes (112 patients which had undergone LASIK operation were assessed. These patients had referred to Aban Eye Clinic, Isfahan, Iran, during August and September 2002. Corneal thickness was measured by ORB SCAN Topoghraphy, and cycloplegic refraction was performed with autorefratometery and retinoscopy. Suspected keratoconus cases and hyperopic patients were excluded. Results: The patients' age was 27.2 ± 1.36 in men (N = 35 and 30.13 ± 1.04 in women (N = 77. Mean value of myopic refractory error in male patients was 5.1 ± 0.24D and in female patients was 3.8 ± 0.36D. Mean of corneal thickness was 540 ± 5.25 µM and 530 ± 5.88 µM in male and female patients respectively. There was no correlation between the degree of myopia and corneal thickness in any of the patients. Also in this research, no relations between the age and myopia were found. Right eye (P > 0.5, r = 0.124 Left eye (P > 0.5, r = 0.104. Conclusion: Based on our findings, corneal thickness and myopic refectory error do not seem to have any relations. (r = 0.039, p = 0.684. Keywords: Corneal Thickness, Cornea, Myopia, LASIK, Refractory Error

  14. [Correlation between Goldmann and non-contact tonometry based on corneal thickness].

    Schepens, G; Urier, N; Bechetoille, A; De Potter, P

    2001-01-01

    In this transversal study, we measure the intra ocular pressure by means of the Goldmann tonometer and a Non-Contact tonometer along with the central cornea thickness in 136 eyes of 73 patients. The statistical analysis of the collected data doesn't allow us to establish a correlation between the variation of the corneal thickness and the difference between the Goldmann tonometer and Non-Contact tonometer measures. The relative precision of the Non-Contact tonometer compared with the Goldmann tonometer doesn't seem influenced by the central cornea thickness.

  15. Corneal power, thickness, and stiffness: results of a prospective randomized controlled trial of PRK and LASIK for myopia.

    Hjortdal, Jesper Ø; Møller-Pedersen, Torben; Ivarsen, Anders; Ehlers, Niels

    2005-01-01

    To compare the short-, medium-, and long-term changes in corneal optical power and corneal aberrations, central corneal thickness, and corneal "stiffness" assessed by pneumotonometry readings in patients having laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) for myopia. Department of Ophthalmology, Arhus University Hospital, Arhus, Denmark. One eye of each of 45 patients with myopia ranging from -6.00 to -8.00 diopters (D) (spherical equivalent spectacle refraction [SER]) was randomized to LASIK (n=25; mean SER -7.12 D +/- 0.57 [SD]) or PRK (n=20; mean SER -6.91 +/- 0.57 D). Data were collected prospectively before and 1, 3, 6, 12, and 36 months after surgery. Measurements included corneal topography (TMS-1, Tomey), corneal thickness (ultrasound pachymetry), and apparent intraocular pressure (IOP) (pneumotonometry). Retreatments were not performed during the first year, and retreated eyes were excluded from the 3-year follow-up. Changes in corneal power and aberrations, thickness, and apparent IOP were calculated in a pair-wise manner for 3 time periods: short term (preoperative to 1 month after surgery), medium term (1 to 12 months after surgery), and long term (1 to 3 years after surgery). In the short term, corneal power decreased equally in LASIK and PRK eyes. Spherical aberrations and coma-like aberrations increased equally, while corneal thickness decreased significantly less in LASIK eyes than in PRK eyes. The apparent IOP decreased more in LASIK eyes than in PRK eyes. In the medium term, corneal power increased significantly in both groups. Spherical aberrations decreased significantly in PRK eyes but not in LASIK eyes. From 1 to 12 months, corneal thickness increased more in PRK eyes than in LASIK eyes. During this period, the apparent IOP increased significantly in LASIK eyes. In the long term, corneal power and corneal aberrations did not change significantly in either group. Corneal thickness increased slightly but

  16. Biomechanical corneal changes induced by different flap thickness created by femtosecond laser

    Fabricio W. Medeiros

    2011-01-01

    Full Text Available OBJECTIVE: To evaluate the impact of the creation of corneal flaps at different thicknesses on the biomechanical properties of swine corneas. METHOD: Twelve swine eyes were obtained to form two groups: 100 μm flap thickness and 300 μm flap thickness. Each eye was submitted to the following examinations: raster topography to investigate corneal curvature alterations, ocular response analyzer to investigate corneal hysteresis change, optical coherence tomography to measure central corneal and flap thickness and sonic wave propagation velocity as a measure of stiffness, before and immediately after flap creation. After flap amputation, surface wave velocity measurements were repeated. RESULTS: Measured flap thicknesses were statistically different for thin and thick flap groups, with an average of 108.5 + 6.9 and 307.8 + 11.5 μm respectively. Hysteresis and corneal resistance factor did not change significantly after flap creation in the thin flap group. With thicker flaps, both parameters decreased significantly from 8.0 +1.0 to 5.1 +1.5 mmHg and from 8.2 + 1.6 to 4.1 +2.5 mmHg respectively. Simulated keratometry values increased in the thick flap group (from 39.5 + 1 D to 45.9+1.2 D after flap creation but not in the thin flap group (from 40.6 + 0.6 D to 41.4+ 1.0 D. Regarding surface wave velocity analysis, the surgical procedures induced statistically lower results in some positions. CONCLUSION: In the experimental conditions established by this model, thicker flaps presented a greater biomechanical impact on the cornea.

  17. Clinical estimation of intraocular pressure with a non-contact tonometer and Goldman applanation tonometer as a tool for mass screening and its correlation with central corneal thickness: A comparative hospital based study

    Anshulee Sood

    2015-01-01

    Full Text Available Purpose To assess the mean difference between intra-ocular pressure measurement by Goldmann applanation tonometer and Non Contact tonometer to determine the suitability of tonometer for community or mass screening and the variation in intra-ocular pressure between the two devices with respect to CCT. Material and Methods The proposed study was conducted on 300 eyes of 150 patients. The IOP assessment with the Goldmann applanation tonometer was always subsequent to that with the air-puff noncontact tonometer (AT-555. An average of three readings taken 15 seconds apart, with each method was taken to get final intraocular pressure reading for each eye. The central corneal thickness (CCT measurements were performed using the pachymeter. Results Majority of the eyes were found to be in the 12-24 mmHg group i.e. 51 % eyes in the right eye and 64 % in the left eye. 3. Mean IOP measured with NCT was 22.30±10.149 mmHg and with GAT was 18.31±7.427 mmHg, thus showing a difference of 3.99 mmHg. In patients where IOP was 24mm Hg the difference in the mean IOP for right eye was 5.69mmHg and for left eye 7.84mmHg (p<0.001. Both the methods of IOP measurement showed positive correlation with central corneal thickness. The NCT was more influenced by CCT than GAT; for every 10 micron CCT change, the IOP change expected with NCT was 0.47 mmHg and GAT was 0.29 mmHg. Conclusion Thus we can conclude that NCT can be used as a screening procedure in tertiary care centres catering to a large number of patients wherein it is not possible to do Goldmann applanation tonometry on all patients.. However, intraocular pressure readings may require adjustment, especially when measured with NCT in those patients who have a CCT that is significantly different from population mean.

  18. Intraocular pressure in a cohort of healthy eastern European schoolchildren: variations in method and corneal thickness

    2012-01-01

    Background Intraocular pressure (IOP) in the developing eye of a child is not always easy to measure and there is no technique that is known to be the most accurate for the young eye. Measurements are needed on many cohorts of children with different tonometers to determine how the values correlate between instruments, whether corneal parameters affect readings and whether correlations between age and IOP values can be discerned. The aim of this study was to undertake a comparative analysis of three different tonometers on a group of healthy children to see whether differences exist and whether these may be related to central corneal thickness and/or radius of curvature. In addition, the study adds to the relatively small body of literature on IOP in the growing eye which will collectively allow trends to be identified and ultimately norms to be established. Methods IOP was measured on 115 eyes in a group of Polish children, aged between 5–17 years (mean ± standard deviation [SD] 11.3 ± 3.0 years) using three different tonometers: non-contact (NCT), the ICare and Goldmann applanation (GAT). Readings obtained were compared between instruments and with central corneal thickness and radius of curvature. Results The ICare tonometer provided statistically higher IOP values (16.9 ± 3.4 mmHg) than the GAT (14.7 ± 2.9 mmHg) regardless of corneal thickness and whether or not a correction factor was applied. A correlation was found between central corneal thickness (CCT) and IOP values obtained with all three tonometers but only the IOP values detected with the ICare tonometer showed a statistically significant correlation with radius of curvature (p < 0.004). No correlations with age or gender were found for IOP values measured with any of the instruments. Conclusions IOP measurements on children vary significantly between instruments and correlations are affected by the corneal thickness. Further studies on children are needed to determine which

  19. Intraocular pressure in a cohort of healthy eastern European schoolchildren: variations in method and corneal thickness

    Krzyżanowska-Berkowska Patrycja

    2012-12-01

    Full Text Available Abstract Background Intraocular pressure (IOP in the developing eye of a child is not always easy to measure and there is no technique that is known to be the most accurate for the young eye. Measurements are needed on many cohorts of children with different tonometers to determine how the values correlate between instruments, whether corneal parameters affect readings and whether correlations between age and IOP values can be discerned. The aim of this study was to undertake a comparative analysis of three different tonometers on a group of healthy children to see whether differences exist and whether these may be related to central corneal thickness and/or radius of curvature. In addition, the study adds to the relatively small body of literature on IOP in the growing eye which will collectively allow trends to be identified and ultimately norms to be established. Methods IOP was measured on 115 eyes in a group of Polish children, aged between 5–17 years (mean ± standard deviation [SD] 11.3 ± 3.0 years using three different tonometers: non-contact (NCT, the ICare and Goldmann applanation (GAT. Readings obtained were compared between instruments and with central corneal thickness and radius of curvature. Results The ICare tonometer provided statistically higher IOP values (16.9 ± 3.4 mmHg than the GAT (14.7 ± 2.9 mmHg regardless of corneal thickness and whether or not a correction factor was applied. A correlation was found between central corneal thickness (CCT and IOP values obtained with all three tonometers but only the IOP values detected with the ICare tonometer showed a statistically significant correlation with radius of curvature (p  Conclusions IOP measurements on children vary significantly between instruments and correlations are affected by the corneal thickness. Further studies on children are needed to determine which instrument is most appropriate and to derive a normative IOP scale for the growing eye.

  20. Assessment of Corneal Epithelial Thickness in Asymmetric Keratoconic Eyes and Normal Eyes Using Fourier Domain Optical Coherence Tomography

    S. Catalan

    2016-01-01

    Full Text Available Purpose. To compare the characteristics of asymmetric keratoconic eyes and normal eyes by Fourier domain optical coherence tomography (OCT corneal mapping. Methods. Retrospective corneal and epithelial thickness OCT data for 74 patients were compared in three groups of eyes: keratoconic (n=22 and normal fellow eyes (n=22 in patients with asymmetric keratoconus and normal eyes (n=104 in healthy subjects. Areas under the curve (AUC of receiver operator characteristic (ROC curves for each variable were compared across groups to indicate their discrimination capacity. Results. Three variables were found to differ significantly between fellow eyes and normal eyes (all p<0.05: minimum corneal thickness, thinnest corneal point, and central corneal thickness. These variables combined showed a high discrimination power to differentiate fellow eyes from normal eyes indicated by an AUC of 0.840 (95% CI: 0.762–0.918. Conclusions. Our findings indicate that topographically normal fellow eyes in patients with very asymmetric keratoconus differ from the eyes of healthy individuals in terms of their corneal epithelial and pachymetry maps. This type of information could be useful for an early diagnosis of keratoconus in topographically normal eyes.

  1. Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases

    Iglesias, A.I. (Adriana I.); A. Mishra (Aniket); V. Vitart (Veronique); Y. Bykhovskaya (Yelena); R. Höhn (René); H. Springelkamp (Henriët); G. Cuellar-Partida (Gabriel); P. Gharahkhani (Puya); Bailey, J.N.C. (Jessica N. Cooke); Willoughby, C.E. (Colin E.); X. Li (Xiaohui); S. Yazar (Seyhan); A. Nag (Abhishek); A.P. Khawaja (Anthony); O. Polasek (Ozren); D.S. Siscovick (David); Mitchell, P. (Paul); Y.C. Tham (Yih Chung); J.L. Haines (Jonathan); L.S. Kearns (Lisa S.); C. Hayward (Caroline); Shi, Y. (Yuan); Van Leeuwen, E.M. (Elisabeth M.); K.D. Taylor (Kent); Wang, J.J. (Jie Jin); E. Rochtchina (Elena); J. Attia (John); Scott, R. (Rodney); E.G. Holliday (Elizabeth); P.N. Baird (Paul); Xie, J. (Jing); Inouye, M. (Michael); Viswanathan, A. (Ananth); X. Sim (Xueling); P.W.M. Bonnemaijer (Pieter); J.I. Rotter (Jerome I.); Martin, N.G. (Nicholas G.); T. Zeller (Tanja); R.A. Mills (Richard); S.E. Staffieri (Sandra E.); Jonas, J.B. (Jost B.); Schmidtmann, I. (Irene); T. Boutin (Thibaud); Kang, J.H. (Jae H.); S.E.M. Lucas (Sionne E.M.); Wong, T.Y. (Tien Yin); Beutel, M.E. (Manfred E.); Wilson, J.F. (James F.); R.R. Allingham (R Rand); M.H. Brilliant (Murray H.); D.L. Budenz (Donald L.); W.G. Christen (William G.); J. Fingert (John); D.S. Friedman (David); Gaasterland, D. (Douglas); T. Gaasterland (Terry); M.A. Hauser (Michael); P. Kraft (Peter); Lee, R.K. (Richard K.); P.A. Lichter (Paul A.); Liu, Y. (Yutao); S.J. Loomis (Stephanie J.); S.E. Moroi (Sayoko); M.A. Pericak-Vance (Margaret); A. Realini (Anthony); Richards, J.E. (Julia E.); J.S. Schuman (Joel S.); W.K. Scott (William); K. Singh (Kuldev); A.J. Sit (Arthur J.); D. Vollrath (Douglas); R.N. Weinreb (Robert N.); G. Wollstein (Gadi); D.J. Zack (Donald); K. Zhang (Kang); Donnelly, P. (Peter); I.E. Barroso (Inês); Blackwell, J.M. (Jenefer M.); E. Bramon (Elvira); M.A. Brown (Matthew); J.P. Casas (Juan); A. Corvin (Aiden); Deloukas, P. (Panos); A. Duncanson (Audrey); Jankowski, J. (Janusz); H.S. Markus (Hugh); J. Mathew (Joseph); C.N.A. Palmer (Colin); R. Plomin (Robert); A. Rautanen (Anna); S.J. Sawcer (Stephen); R.C. Trembath (Richard); Wood, N.W. (Nicholas W.); C.C.A. Spencer (Chris C.); G. Band (Gavin); C. Bellenguez (Céline); Freeman, C. (Colin); F.A. Hellenthal; E. Giannoulatou (Eleni); M. Pirinen (Matti); R. Pearson (Ruth); A. Strange (Amy); Z. Su (Zhan); D. Vukcevic (Damjan); Langford, C. (Cordelia); Hunt, S.E. (Sarah E.); T. Edkins (Ted); R. Gwilliam (Rhian); H. Blackburn (Hannah); S. Bumpstead (Suzannah); S. Dronov (Serge); M. Gillman (Matthew); E. Gray (Emma); N. Hammond (Naomi); A. Jayakumar (Alagurevathi); O.T. McCann (Owen); J. Liddle (Jennifer); S.C. Potter (Simon); Ravindrarajah, R. (Radhi); Ricketts, M. (Michelle); P. Waller (Patrick); P. Weston (Paul); S. Widaa (Sara); Whittaker, P. (Pamela); A.G. Uitterlinden (André); E.N. Vithana (Eranga); P.J. Foster (Paul); P.G. Hysi (Pirro); Hewitt, A.W. (Alex W.); C.C. Khor; L.R. Pasquale (Louis); Montgomery, G.W. (Grant W.); C.C.W. Klaver (Caroline); T. Aung (Tin); A.F.H. Pfeiffer (Andreas); D.A. Mackey (David); C.J. Hammond (Christopher); Cheng, C.-Y. (Ching-Yu); J.E. Craig (Jamie); Y.S. Rabinowitz (Yaron); J.L. Wiggs (Janey L.); K.P. Burdon (Kathryn); C.M. van Duijn (Cornelia); MacGregor, S. (Stuart)

    2018-01-01

    textabstractCentral corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related

  2. Relationship between Central Corneal Thickness, Vitreous ...

    eye health and also aid in developing strategies to help early diagnoses and management of ... of disease, determining the effec veness of medical .... air-dry. A drop of topical anaesthe c (Tetracaine HCl. 0.1%) was ins lled in subject's eye.

  3. Dynamic contour tonometry vs. non-contact tonometry and their relation with corneal thickness

    Briceño, Adriana; Mas, David; Domenech, Begoña

    2016-01-01

    The purpose of this study is to evaluate the concordance between intraocular pressure (IOP) values obtained with a dynamic contour tonometer (DCT) and a non-contact tonometer (NCT) in healthy patients and to investigate the effect of central corneal thickness (CCT) on IOP readings for each of the two measuring systems. The mean IOP yielded by DCT, NCT and corrected non-contact tonometer (CNCT) was 17.1 mmHg, 15.5 mmHg and 12.2 mmHg, respectively. The average CCT was 563.6 μm and the ocular pu...

  4. Explore the full thick layer of corneal transplantation in the treatment of pseudomonas aeruginosa corneal ulcer infection

    Xin Wang

    2015-02-01

    Full Text Available AIM: To explore the feasibility, safety and effect of the full-thickness lamellar keratoplasty for the treatment of pseudomonas aeruginosa corneal ulcer. METHODS: Based on a retrospective non-controlled study, 25 patients were given the full-thickness lamellar keratoplasty for clinical diagnosis of pseudomonas aeruginosa infection and corneal ulcer medication conventional anti-gram-negative bacteria. Routine follow-up were carried out at postoperative 1wk; 1, 3, 6, 12, 18mo to observe the situation of corneal epithelial healing, recurrent infection, immune rejection, graft transparency and best corrected visual acuity, etc. At the 6 and 12mo postoperative, corneal endothelial cell density was reexamined.RESULTS: No patients because of Descemet's membrane rupture underwent penetrating keratoplasty surgery: One only in cases of bacterial infection after 1mo, once again did not cultivate a culture of bacteria pseudomonas aeruginosa, and the remaining 24 cases average follow-up 14±6mo, corneal graft were transparent, the cure rate was 96%. At the sixth month after surgery, there were 16 cases of eye surgery best corrected visual acuity ≥4.5, of which 3 cases ≥4.8. At the sixth month after surgery, the average corneal endothelial cell density 2 425±278/mm2; At 12mo postoperatively, it was 2 257± 326/mm2.CONCLUSION: Full-thickness lamellar keratoplasty is an effective method of pseudomonas aeruginosa infection in the treatment of corneal ulcers, corneal drying material glycerol can be achieved by visual effects.

  5. Corneal thickness and elevation measurements using swept-source optical coherence tomography and slit scanning topography in normal and keratoconic eyes.

    Jhanji, Vishal; Yang, Bingzhi; Yu, Marco; Ye, Cong; Leung, Christopher K S

    2013-11-01

    To compare corneal thickness and corneal elevation using swept source optical coherence tomography and slit scanning topography. Prospective study. 41 normal and 46 keratoconus subjects. All eyes were imaged using swept source optical coherence tomography and slit scanning tomography during the same visit. Mean corneal thickness and best-fit sphere measurements were compared between the instruments. Agreement of measurements between swept source optical coherence tomography and scanning slit topography was analyzed. Intra-rater reproducibility coefficient and intraclass correlation coefficient were evaluated. In normal eyes, central corneal thickness measured by swept source optical coherence tomography was thinner compared with slit scanning topography (p topography. In keratoconus eyes, central corneal thickness was thinner on swept source optical coherence tomography than slit scanning topography (p = 0.081) and ultrasound pachymetry (p = 0.001). There were significant differences between thinnest corneal thickness, and, anterior and posterior best-fit sphere measurements between both instruments (p topography. With better reproducibility coefficients and intraclass correlation coefficients, swept source optical coherence tomography may provide a reliable alternative for measurement of corneal parameters. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  6. Hypobaric Hypoxia: Effects on Intraocular Pressure and Corneal Thickness

    Marcella Nebbioso

    2014-01-01

    Full Text Available Objective. The purpose of this study focused on understanding the mechanisms underlying ocular hydrodynamics and the changes which occur in the eyes of subjects exposed to hypobaric hypoxia (HH to permit the achievement of more detailed knowledge in glaucomatous disease. Methods. Twenty male subjects, aged 32±5 years, attending the Italian Air Force, were enrolled for this study. The research derived from hypobaric chamber, using helmet and mask supplied to jet pilotes connected to oxygen cylinder and equipped with a preset automatic mixer. Results. The baseline values of intraocular pressure (IOP, recorded at T1, showed a mean of 16±2.23 mmHg, while climbing up to 18,000 feet the mean value was 13.7±4.17 mmHg, recorded at T2. The last assessment was performed returning to sea level (T4 where the mean IOP value was 12.8±2.57 mmHg, with a significant change (P<0.05 compared to T1. Pachymetry values related to corneal thickness in conditions of hypobarism revealed a statistically significant increase (P<0.05. Conclusions. The data collected in this research seem to confirm the increasing outflow of aqueous humor (AH in the trabecular meshwork (TM under conditions of HH.

  7. Postoperative influences of the torsional phacoemulsification on foveal thickness and corneal edema

    Lei Li

    2014-05-01

    Full Text Available AIM: To report the influences onfoveal thickness and corneal edema after torsional phacoemulsification.METHODS: Totally 52 patients(52 eyeswith age-related cataract were randomly assigned to phacoemulsification using torsional mode(26 eyesor conventional ultrasound mode(26 eyes. The foveal thickness examined by optical coherence tomography(OCTafter surgery at 1, 4 and 12wk and corneal edema was examined by slit lamp after surgery at 1d.RESULTS: The postoperative averagefoveal thickness datas of the two groups, comparing with corresponding preoperative datas, were significantly augmented at 1, 4 and 12wk(PPP>0.05. The effects of corneal edema in torsional group were slighter(PCONCLUSION: The postoperative influences onfoveal thickness and corneal edema with torsional mode are slighter than that with ultrasound mode, and the postoperative reactions with torsional mode are efficiently reduced.

  8. Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

    Carlos Gustavo V. De Moraes; Tiago S. Prata; Jeffrey Liebmann; Robert Ritch

    2008-01-01

    Recent advances in tonometry have led to the development of a number of devices with differing clinical applications. Their role in cases of abnormal corneal thickness and surface irregularities is particularly important, as inaccurate estimation of the true intraocular pressure (IOP) in such cases may lead to suboptimal evaluation. The purpose of the present review was to evaluate the accuracy of the most widely used devices in cases of corneal thickness and surface irregularities, based ...

  9. Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases

    Iglesias, Adriana I; Mishra, Aniket; Vitart, Veronique; Bykhovskaya, Yelena; Höhn, René; Springelkamp, Henriët; Cuellar-Partida, Gabriel; Gharahkhani, Puya; Bailey, Jessica N Cooke; Willoughby, Colin E; Li, Xiaohui; Yazar, Seyhan; Nag, Abhishek; Khawaja, Anthony P.; Polasek, Ozren

    2018-01-01

    Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. Pathway analyses uncover new, as well as supported the role of connective tissue-related, pathways. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan,...

  10. Comparison of high-resolution Scheimpflug and high-frequency ultrasound biomicroscopy to anterior-segment OCT corneal thickness measurements

    Kanellopoulos AJ

    2013-11-01

    Full Text Available Anastasios John Kanellopoulos,1,2 George Asimellis1 1Laservision.gr Eye Institute, Athens, Greece; 2New York University Medical School, New York, NY, USA Background: The purpose of this study was to compare and correlate central corneal thickness in healthy, nonoperated eyes with three advanced anterior-segment imaging systems: a high-resolution Scheimpflug tomography camera (Oculyzer II, a spectral-domain anterior-segment optical coherence tomography (AS-OCT system, and a high-frequency ultrasound biomicroscopy (HF-UBM system. Methods: Fifty eyes randomly selected from 50 patients were included in the study. Inclusion criteria were healthy, nonoperated eyes examined consecutively by the same examiner. Corneal imaging was performed by three different methods, ie, Oculyzer II, spectral-domain AS-OCT, and FH-UBM. Central corneal thickness measurements were compared using scatter diagrams, Bland-Altman plots (with bias and 95% confidence intervals, and two-paired analysis. Results: The coefficient of determination (r2 between the Oculyzer II and AS-OCT measurements was 0.895. Likewise, the coefficient was 0.893 between the Oculyzer II and HF-UBM and 0.830 between the AS-OCT and HF-UBM. The trend line coefficients of linearity were 0.925 between the Oculyzer II and the AS-OCT, 1.006 between the Oculyzer II and HF-UBM, and 0.841 between the AS-OCT and HF-UBM. The differences in average corneal thickness between the three pairs of CCT measurements were –6.86 µm between the Oculyzer II and HF-UBM, –12.20 µm between the AS-OCT and Oculyzer II, and +19.06 µm between the HF-UBM and AS-OCT. Conclusion: The three methods used for corneal thickness measurement are highly correlated. Compared with the Scheimplug and ultrasound devices, the AS-OCT appears to report a more accurate, but overally thinner corneal pachymetry. Keywords: anterior eye segment, high-frequency ultrasound biomicroscopy, optical coherence tomography, high-resolution Pentacam

  11. Espesor corneal y variables epidemiológicas y fisiológicas en población de riesgo de glaucoma Corneal thickness and the epidemiological and physiological variables seen in the glaucoma risk population

    Idalia Triana Casado

    2012-12-01

    Full Text Available Objetivo: caracterizar el espesor corneal central en pacientes con factores de riesgo de glaucoma crónico simple. Métodos: se realizó un estudio epidemiológico, observacional, descriptivo y longitudinal prospectivo, en el Servicio de Glaucoma del Hospital "Dr. Salvador Allende" durante el año 2010. El universo estuvo constituido por 1 238 pacientes que acudieron a la consulta de oftalmología por síntomas astenópicos. La muestra, aplicados los criterios de inclusión y exclusión, quedó conformada por 656 pacientes con factores de riesgo de la enfermedad, de estos se desecharon 19 por una diferencia entre los ojos de 10 µm o más de espesor corneal. Las variables analizadas fueron: espesor corneal, edad, sexo, color de la piel y presión intraocular. Resultados: de los pacientes con factores de riesgo de glaucoma, predominaron aquellos entre 50 y 59 años de edad (22,76 %, masculinos (60,28 % y de piel no blanca (57,29 %. El espesor corneal estuvo disminuido (61,85 % y la presión intraocular aumentada (55,41 %, aún con ajuste (46,93 %. Conclusiones: la disminución del espesor corneal estuvo relacionada con la edad, el sexo femenino, la piel no blanca y el aumento de la presión intraocular en aquellos pacientes sospechosos de glaucoma.Objective: to characterize the central corneal thickness seen in patients with simple chronic glaucoma risk factors. Methods: a prospective longitudinal, descriptive, observational, and epidemiological study was conducted in the Glaucoma Service of “Dr. Salvador Allende” hospital during 2010. The universe of study was made up of 1 238 patients that went to the ophthalmological service due to asthenopic symptoms. Taking the inclusion and exclusion criteria into account, the final sample was composed by 656 patients with glaucoma risk factors, 19 of whom were excluded because of 10 µm and over difference in the corneal thickness between the eyes. The analyzed variables were corneal thickness, age

  12. Corneal thickness in dry eyes in an Iraqi population

    Ali,Noora Mauwafak; Hamied,Furkaan M; Farhood,Qasim K

    2017-01-01

    Noora Mauwafak Ali,1 Furkaan M Hamied,1 Qasim K Farhood2 1Department of Surgery, College of Medicine, Al-Qadisiya University, Diwaniyah, 2Department of Surgery, College of Medicine, University of Babylon, Hillah, Iraq Background: Dry eye disorder is a multifactorial disease of the tears and ocular surface that results in discomfort and visual disturbance. Corneal pachymetry becomes increasingly important in refractive surgery, for the accurate assessment of intraocular pressure, and in the ...

  13. The effect of flap thickness on corneal biomechanics after myopic laser in situ keratomileusis using the M-2 microkeratome

    Goussous IA

    2017-11-01

    Full Text Available Iyad A Goussous,1 Mohamed-Sameh El-Agha,1 Ahmed Awadein,1 Mohamed H Hosny,1 Alaa A Ghaith,2 Ahmed L Khattab2 1Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, 2Faculty of Medicine, Alexandria University, Alexandria, Egypt Purpose: The purpose of this study was to determine the effect of flap thickness on corneal biomechanics after myopic laser in situ keratomileusis (LASIK.Methods: This is a prospective controlled non-randomized, institutional study. Patients underwent either epi-LASIK with mitomycin (advanced surface ablation [ASA], thin-flap LASIK (90 µm head, or thick-flap LASIK (130 µm head. In ASA, the Moria Epi-K hydroseparator was used. LASIK flaps were created using the Moria M-2 mechanical microkeratome. The corneal hysteresis (CH and corneal resistance factor (CRF were measured preoperatively and 3 months after surgery, using the Ocular Response Analyzer®.Results: Ten patients (19 eyes underwent ASA, 11 patients (16 eyes underwent thin-flap LASIK, and 11 patients (16 eyes underwent thick-flap LASIK. The mean preoperative CH was 10.47±0.88, 10.52±1.4, and 11.28±1.4 mmHg (p=0.043, respectively, decreasing after surgery by 1.75±1.02, 1.66±1.00, and 2.62±1.03 mmHg (p=0.017. The mean reduction of CH per micron of central corneal ablation was 0.031, 0.023, and 0.049 mmHg/µm (p=0.005. Mean preoperative CRF was 10.11±1.28, 10.34±1.87, and 10.62±1.76 mmHg (p=0.66, decreasing after surgery by 2.33±1.35, 2.77±1.03, and 2.92±1.10 mmHg (p=0.308. The mean reduction of CRF per micron of central corneal ablation was 0.039, 0.040, and 0.051 mmHg/µm (p=0.112.Conclusion: Thick-flap LASIK caused a greater reduction of CH and CRF than thin-flap LASIK and ASA, although this was statistically significant only for CH. ASA and thin-flap LASIK were found to be biomechanically similar. Keywords: flap thickness ectasia, hysteresis, LASIK, surface ablation

  14. The effect of flap thickness on corneal biomechanics after myopic laser in situ keratomileusis using the M-2 microkeratome.

    Goussous, Iyad A; El-Agha, Mohamed-Sameh; Awadein, Ahmed; Hosny, Mohamed H; Ghaith, Alaa A; Khattab, Ahmed L

    2017-01-01

    The purpose of this study was to determine the effect of flap thickness on corneal biomechanics after myopic laser in situ keratomileusis (LASIK). This is a prospective controlled non-randomized, institutional study. Patients underwent either epi-LASIK with mitomycin (advanced surface ablation [ASA]), thin-flap LASIK (90 µm head), or thick-flap LASIK (130 µm head). In ASA, the Moria Epi-K hydroseparator was used. LASIK flaps were created using the Moria M-2 mechanical microkeratome. The corneal hysteresis (CH) and corneal resistance factor (CRF) were measured preoperatively and 3 months after surgery, using the Ocular Response Analyzer ® . Ten patients (19 eyes) underwent ASA, 11 patients (16 eyes) underwent thin-flap LASIK, and 11 patients (16 eyes) underwent thick-flap LASIK. The mean preoperative CH was 10.47±0.88, 10.52±1.4, and 11.28±1.4 mmHg ( p =0.043), respectively, decreasing after surgery by 1.75±1.02, 1.66±1.00, and 2.62±1.03 mmHg ( p =0.017). The mean reduction of CH per micron of central corneal ablation was 0.031, 0.023, and 0.049 mmHg/µm ( p =0.005). Mean preoperative CRF was 10.11±1.28, 10.34±1.87, and 10.62±1.76 mmHg ( p =0.66), decreasing after surgery by 2.33±1.35, 2.77±1.03, and 2.92±1.10 mmHg ( p =0.308). The mean reduction of CRF per micron of central corneal ablation was 0.039, 0.040, and 0.051 mmHg/µm ( p =0.112). Thick-flap LASIK caused a greater reduction of CH and CRF than thin-flap LASIK and ASA, although this was statistically significant only for CH. ASA and thin-flap LASIK were found to be biomechanically similar.

  15. Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

    De Moraes, Carlos Gustavo V.; Prata, Tiago S.; Liebmann, Jeffrey; Ritch, Robert

    2010-01-01

    Recent advances in tonometry have led to the development of a number of devices with differing clinical applications. Their role in cases of abnormal corneal thickness and surface irregularities is particularly important, as inaccurate estimation of the true intraocular pressure (IOP) in such cases may lead to suboptimal evaluation. The purpose of the present review was to evaluate the accuracy of the most widely used devices in cases of corneal thickness and surface irregularities, based on a survey of the published literature. The analysis was based on a Medline search focusing mainly on papers that have evaluated the devices’ accuracy with respect to corneal thickness and irregularities. Nine device types (Goldmann tonometer, Tono-Pen, Perkins tonometer, Ocular Response Analyzer, non-contact tonometer, pneumatonometer, I-Care rebound tonometer, Pascal dynamic contour tonometer (DCT) and Phosphene tonometer) were described in detail. Moreover, the physical principles and major utility of each tonometer were compared. Each of the many different commercially available tonometers has specific advantages and disadvantages. New non-invasive technologies are getting closer to a precise estimation of the true IOP. However, among all tonometers, none is highly accurate when both corneal thickness and surface irregularities are present. Fifty years after its development, Goldmann tonometry remains the gold standard to which all other devices are compared.

  16. Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

    Carlos Gustavo V. De Moraes

    2008-01-01

    Each of the many different commercially available tonometers has specific advantages and disadvantages. New non-invasive technologies are getting closer to a precise estimation of the true IOP. However, among all tonometers, none is highly accurate when both corneal thickness and surface irregularities are present. Fifty years after its development, Goldmann tonometry remains the gold standard to which all other devices are compared.

  17. Dry eyes and corneal sensation after laser in situ keratomileusis with femtosecond laser flap creation Effect of hinge position, hinge angle, and flap thickness.

    Mian, Shahzad I; Li, Amy Y; Dutta, Satavisha; Musch, David C; Shtein, Roni M

    2009-12-01

    To determine whether corneal sensation and dry-eye signs and symptoms after myopic laser in situ keratomileusis (LASIK) surgery with a femtosecond laser are affected by varying hinge position, hinge angle, or flap thickness. University-based academic practice, Ann Arbor, Michigan, USA. This prospective randomized contralateral-eye study evaluated eyes after bilateral myopic LASIK with a femtosecond laser (IntraLase). Superior and temporal hinge positions, 45-degree and 90-degree hinge angles, and 100 microm and 130 microm corneal flap thicknesses were compared. Postoperative follow-up at 1 week and 1, 3, 6, and 12 months included central Cochet-Bonnet esthesiometry, the Ocular Surface Disease Index questionnaire, a Schirmer test with anesthesia, tear breakup time (TBUT), corneal fluorescein staining, and conjunctival lissamine green staining. The study evaluated 190 consecutive eyes (95 patients). Corneal sensation was reduced at all postoperative visits, with improvement over 12 months (P<.001). There was no difference in corneal sensation between the different hinge positions, angles, or flap thicknesses at any time point. The overall ocular surface disease index score was increased at 1 week, 1 month, and 3 months (P<.0001, P<.0001, and P = .046, respectively). The percentage of patients with a TBUT longer than 10 seconds was significantly lower at 1 week and 1 month (P<.0001). Dry-eye syndrome after myopic LASIK with a femtosecond laser was mild and improved after 3 months. Corneal flap hinge position, hinge angle, and thickness had no effect on corneal sensation or dry-eye syndrome.

  18. A review of corneal diameter, curvature and thickness values and influencing factors*

    K. P. Mashige

    2013-12-01

    Full Text Available The cornea is an important ocular structure involved in the mediation of visual perception. It is the principal refractive surface of the eye and vision can be significantly affected by relatively small changes in its structure and parameters. Measurement of corneal parameters is important in the diagnosis and management of ocular diseasessuch as keratoconus and glaucoma, and also in the fitting of contact lenses or with refractive surgery such as Laser-Assisted in situ Keratomileusis(LASIK and photorefractive keratectomy (PRK. The human corneal diameter, anterior curvature and centre thickness as well as factors influencing them are reviewed in this article. This review will be useful to eye care professionals who routinely measure these parameters when fitting contact lenses and assessing, diagnosing as well as managing corneal and other ocular conditions. (S Afr Optom 2013 72(4 185-194

  19. Influence of corneal thickness on comparative intraocular pressure measurements with Goldmann and non-contact tonometers in keratoconus.

    Stabuc Silih, Mirna; Hawlina, Marko

    2003-12-01

    The influence of corneal thickness and curvature on the difference between intraocular pressure (IOP) measurements obtained with non-contact (NCT) and those with the Goldmann applanation tonometer (GAT) was studied in patients with keratoconus. We examined 113 patients with keratoconus. IOP was measured by the Canon TX 10 non-contact tonometer and the Goldmann tonometer, corneal curvature and thickness were obtained by Humphrey Automatic Refractometer Keratometer and Orbscan Version 3.0 Bausch & Lomb Surgical. The IOP measured by NCT was significantly lower than that measured by GAT. The mean pachymetry of the thinnest point was 423.15 +/- 98.43 microm for the right eyes and 426.7 +/- 93.88 microm for the left eyes. The difference between NCT-GAT and corneal thickness showed a significant negative correlation (r = - 0.427, p < 0.0001; t = - 3.677, p < 0.0001). Values of NCT measurements were significantly increasing with corneal thickness (F = 6.505, p < 0.0001 for right eyes and F = 4.37, p = 0.004 for left eyes), whilst GAT measurements did not show a significant influence of the corneal thickness. The keratometry had no effect on the difference between NCT-GAT measurements (t = 1.090, p = 0.278). The thin cornea has more influence on the measurement with NCT than GAT. The relative precision of NCT compared with GAT seems to be influenced by the corneal thickness.

  20. Corneal thickness changes during corneal collagen cross-linking with UV-A irradiation and hypo-osmolar riboflavin in thin corneas

    Belquiz Amaral Nassaralla

    2013-06-01

    Full Text Available PURPOSE: To evaluate the thinnest corneal thickness changes during and after corneal collagen cross-linking treatment with ultraviolet-A irradiation, using hypo-osmolar riboflavin solution in thin corneas. METHODS: Eighteen eyes of 18 patients were included in this study. After epithelium removal, iso-osmolar 0.1% riboflavin solution was instilled to the cornea every 3 minutes for 30 minutes. Hypo-osmolar 0.1% riboflavin solution was then applied every 20 seconds for 5 minutes or until the thinnest corneal thickness reached 400 µm. Ultraviolet-A irradiation was performed for 30 minutes. During irradiation, iso-osmolar 0.1% riboflavin drops were applied every 5 minutes. Ultrasound pachymetry was performed at approximately the thinnest point of the cornea preoperatively, after epithelial removal, after iso-osmolar riboflavin instillation, after hypo-osmolar riboflavin instillation, after ultraviolet-A irradiation, and at 1, 6 and 12 months after treatment. RESULTS: Mean preoperative thinnest corneal thickness was 380 ± 11 µm. After epithelial removal it decreased to 341 ± 11 µm, and after 30 minutes of iso-osmolar 0.1% riboflavin drops, to 330 ± 7.6 µm. After hypo-osmolar 0.1% riboflavin drops, mean thinnest corneal thickness increased to 418 ± 11 µm. After UVA irradiation, it was 384 ± 10 µm. At 1, 6 and 12 months after treatment, it was 372 ± 10 µm, 381 ± 12.7, and 379 ± 15 µm, respectively. No intraoperative, early postoperative, or late postoperative complications were noted. CONCLUSIONS: Hypo-osmolar 0.1% riboflavin solution seems to be effective for swelling thin corneas. The swelling effect is transient and short acting. Corneal thickness should be monitored throughout the procedure. Larger sample sizes and longer follow-up are required in order to make meaningful conclusions regarding safety.

  1. A case report of central toxic keratopathy in a patient post TransPRK (followed by corneal collagen cross-linking).

    Davey, Nicholas; Aslanides, Ioannis M; Selimis, Vasilis

    2017-01-01

    The purpose of this article is to report a case of central toxic keratopathy in a patient post transepithelial photorefractive keratectomy (TransPRK), followed immediately by corneal collagen cross-linking. This article describes the case of a 26-year-old male after bilateral aberration-free, TransPRK laser (Schwind Amaris 750S). The procedure was performed for compound myopic astigmatism in November 2015, followed immediately by accelerated corneal collagen cross-linking for early keratoconus. From day 3 post-op, tear film debris underneath both contact lenses with corneal haze and early, progressive central anterior stromal opacity formation only in the left eye were noted. At 2 weeks post-op, the left eye was noted to have a significant hyperopic shift with central corneal thinning in the anterior stroma. A central anterior stromal dense opacity had formed in the left eye with the surrounding superficial stromal haze. As of month 2, the opacity gradually started to improve in size and density. The hyperopic shift peaked at 2 months and continued to improve, largely due to epithelial compensation with a gradual recovery of stromal thickness. The question remains as to what provokes the typical central corneal necrosis/thinning in central toxic keratopathy. We hypothesize that the space between the contact lens and the corneal surface post TransPRK is prone to a "pseudo-interface pathology" that could mimic diffuse lamellar keratitis-like pathology. Suboptimal lid hygiene, resulting in tear film combinations of bacteria, inflammatory cells, matrix metalloproteinases and other proteolytic enzymes, contributes to the degradation of vulnerable, exposed collagen stromal tissue post TransPRK or any surface corneal ablation. Refractive surgeons should maintain a healthy lid margin and tear film, especially in contact lens wearers, to prevent potential complications in refractive surgery procedures.

  2. Measurement of central corneal thickness by different techniques

    Reem Hassan Ibrahim Azzam

    2017-01-01

    Conclusion CCT measurements obtained by UBM tend to be thicker than those obtained by pentacam and noncontact specular microscopy, but the measurements of all three are strongly positively correlated with each other. So, any of these devices can be easily substituted by the other for the measurement of CCT.

  3. Evaluation of Human Corneal Lenticule Quality After SMILE With Different Cap Thicknesses Using Scanning Electron Microscopy.

    Weng, Shengbei; Liu, Manli; Yang, Xiaonan; Liu, Fang; Zhou, Yugui; Lin, Haiqin; Liu, Quan

    2018-01-01

    To evaluate the surface characteristics of lenticules created by small-incision lenticule extraction (SMILE) with different cap thicknesses. This prospective study included 20 consecutive patients who underwent bilateral SMILE. Surface regularity of the extracted corneal lenticule was analyzed using scanning electron microscopy (SEM) combined with 2 methods: qualitative and quantitative regularity. Qualitative regularity of SEM images was graded by masked observers using an established scoring system. Quantitative regularity of SEM images was assessed by counting the total number and areas of tissue bridges using Image-Pro Plus software. Four different cap thickness of 120, 130, 140, and 150 μm were compared. Refractive outcomes of patients were measured at baseline and 1 month after surgery. As 10 specimens were not analyzable, only 30 eyes were included. Postoperatively, all eyes had postoperative uncorrected distance visual acuity of 20/20 or better; 43% had an unchanged corrected distance visual acuity; 43% gained 1 line; 10% lost 1 line. Ultrastructurally, surface irregularity was primarily caused by tissue bridges. The average surface regularity score obtained was 10.87 ± 2.40 for 120 μm, 10.78 ± 2.60 for 130 μm, 8.76 ± 2.16 for 140 μm, and 8.70 ± 2.66 for 150 μm (P < 0.001). The total number and areas of tissue bridges of 120 to 130 μm were significantly less than 140 to 150 μm (P < 0.05). Surface regularity decreased as cap thickness increased (P < 0.05). There is smoother appearance of the lenticular surface as seen through SEM when a thin cap is created compared with a thick cap qualitatively and quantitatively.

  4. Quantitative assessment of rat corneal thickness and morphology during stem cell therapy by high-speed optical coherence tomography

    Lal, Cerine; McGrath, James; Subhash, Hrebesh; Rani, Sweta; Ritter, Thomas; Leahy, Martin

    2016-03-01

    Optical Coherence Tomography (OCT) is a non-invasive 3 dimensional optical imaging modality that enables high resolution cross sectional imaging in biological tissues and materials. Its high axial and lateral resolution combined with high sensitivity, imaging depth and wide field of view makes it suitable for wide variety of high resolution medical imaging applications at clinically relevant speed. With the advent of swept source lasers, the imaging speed of OCT has increased considerably in recent years. OCT has been used in ophthalmology to study dynamic changes occurring in the cornea and iris, thereby providing physiological and pathological changes that occur within the anterior segment structures such as in glaucoma, during refractive surgery, lamellar keratoplasty and corneal diseases. In this study, we assess the changes in corneal thickness in the anterior segment of the eye during wound healing process in a rat corneal burn model following stem cell therapy using high speed swept source OCT.

  5. The applicability of correction factor for corneal thickness on non-contact tonometer measured intraocular pressure in LASIK treated eyes.

    Jethani, Jitendra; Dave, Paaraj; Jethani, Monica; Desai, Yogesh; Patel, Purvi

    2016-01-01

    To determine the applicability of central corneal thickness (CCT) based correction factor for non-contact tonometer (NCT) measured intraocular pressure (IOP) readings. A prospective, non-randomized study involved 346 eyes of 173 consecutive patients with age ⩾21 years undergoing laser-assisted in situ keratomileusis (LASIK) for myopia and/or myopic astigmatism. The CCT and IOP were measured before and after the LASIK procedure. The IOP pre and post-LASIK was compared after applying the correction factor for CCT. Patients not completing the 3 month postoperative follow-up were excluded. The median spherical equivalent before undergoing LASIK was -4.25D (inter-quartile range, -3.25D). The mean preoperative CCT was 536.82 ± 33.71 μm which reduced to 477.55 ± 39.3 μm (p < 0.01) post-LASIK. The mean IOP reduced from a preoperative value of 14.6 ± 2.32 mmHg to 10.64 ± 2.45 mmHg postoperatively (p < 0.01). On applying correction for the corneal thickness, the pre and postoperative IOP was 15.14 ± 2.8 mmHg and 15.37 ± 2.65 mmHg (p = 0.06) respectively with a strong positive correlation (r = 0.7, p < 0.01). Three hundred eyes (86.7%) had an absolute difference in IOP of less than 3.0 mmHg post-CCT correction which is within the retest variability of NCT. Only 46 eyes (13.3%) had an absolute difference of more than 3.0 mmHg. The modified Ehler's correction algorithm used in this study can be effectively applied in the normal IOP range in a majority of patients.

  6. A case report of central toxic keratopathy in a patient post TransPRK (followed by corneal collagen cross-linking

    Davey N

    2017-04-01

    Full Text Available Nicholas Davey, Ioannis M Aslanides, Vasilis Selimis Emmetropia Mediterranean Eye Institute, Heraklion, Crete, Greece Purpose: The purpose of this article is to report a case of central toxic keratopathy in a patient post transepithelial photorefractive keratectomy (TransPRK, followed immediately by corneal collagen cross-linking.Methods: This article describes the case of a 26-year-old male after bilateral aberration-free, TransPRK laser (Schwind Amaris 750S. The procedure was performed for compound myopic astigmatism in November 2015, followed immediately by accelerated corneal collagen cross-linking for early keratoconus.Results: From day 3 post-op, tear film debris underneath both contact lenses with corneal haze and early, progressive central anterior stromal opacity formation only in the left eye were noted. At 2 weeks post-op, the left eye was noted to have a significant hyperopic shift with central corneal thinning in the anterior stroma. A central anterior stromal dense opacity had formed in the left eye with the surrounding superficial stromal haze. As of month 2, the opacity gradually started to improve in size and density. The hyperopic shift peaked at 2 months and continued to improve, largely due to epithelial compensation with a gradual recovery of stromal thickness.Conclusion: The question remains as to what provokes the typical central corneal necrosis/thinning in central toxic keratopathy. We hypothesize that the space between the contact lens and the corneal surface post TransPRK is prone to a “pseudo-interface pathology” that could mimic diffuse lamellar keratitis-like pathology. Suboptimal lid hygiene, resulting in tear film combinations of bacteria, inflammatory cells, matrix metalloproteinases and other proteolytic enzymes, contributes to the degradation of vulnerable, exposed collagen stromal tissue post TransPRK or any surface corneal ablation. Refractive surgeons should maintain a healthy lid margin and tear

  7. Repeatability and interobserver reproducibility of Artemis-2 high-frequency ultrasound in determination of human corneal thickness

    Ogbuehi KC

    2012-05-01

    Full Text Available Kelechi C Ogbuehi, Uchechukwu L OsuagwuOutpatient Clinic, Department of Optometry, King Saud University, Riyadh, Kingdom of Saudi ArabiaBackground: The purpose of this study was to assess the repeatability and limits of agreement of corneal thickness values measured by a high-frequency ultrasound (Artemis-2, hand-held ultrasound pachymeter (DGH-500 and a specular microscope (SP-3000P.Methods: Central corneal thickness (CCT was analyzed in this prospective randomized study that included 32 patients (18 men and 14 women aged 21–24 years. Measurements were obtained in two sessions, one week apart, by two examiners with three devices in a randomized order. Nine measurements were taken (three with each device on one randomly selected eye of each patient in each measurement session. The coefficient of repeatability and interobserver reproducibility for the values of each method were calculated. The limits of agreement between techniques were also evaluated.Results: There were no significant differences in CCT values between sessions for each of the three devices (P > 0.05. The repeatability coefficients for the Artemis-2 (±8 µm/±9 µm were superior to those of the SP-3000P (±9 µm/±11 µm and DGH 500 (±12 µm/±12 µm in session 1/session 2 respectively, while the interobserver reproducibility index (differences between session 1 and session 2 was superior for the SP-3000P (±17 µm with respect to DHG-500 (±29 µm and the Artemis-2 (±31 µm. In session 1 and session 2, the limits of agreement between the techniques were 35 µm to -31 µm and 34 to -20 µm, respectively, for DGH-500 versus Artemis-2, 73 µm to 3 µm and 60 µm to 9 µm for Artemis-2 versus SP-3000P, and 58 µm to 22 µm and 72 µm to 10 µm for DGH-500 versus SP-3000P comparisons. The DGH-500 and Artemis-2 gave similar values (P > 0.05 in both sessions, but both (Artemis-2 and DGH-500 values were significantly greater than that of the SP-3000P (P < 0.05 in both sessions

  8. [The influence of corneal thickness and curvature on the difference between intraocular pressure measurements obtained with a non-contact tonometer and those with a Goldmann applanation tonometer].

    Matsumoto, T; Makino, H; Uozato, H; Saishin, M; Miyamoto, S

    2000-05-01

    The influence of corneal thickness and curvature on the difference between intraocular pressure (IOP) measurements obtained with a non-contact tonometer (NCT) and those with a Goldmann applanation tonometer (GAT) was studied. The corneal thickness and curvature were obtained in 230 eyes of 115 subjects. The correlation between them and ratios of measurement with NCT to that with GAT ([NCT/GAT]) were examined. [NCT/GAT] and corneal thickness showed a significant positive correlation (r = 0.556, p < 0.01), but, the correlation between [NCT/GAT] and the radius of corneal curvature was not statistically significant (r = -0.035, p = 0.30). The thick cornea has more influence on the measurement with NCT than GAT, because IOP is measured with NCT over a wider applanation area. The corneas with steeper curvature also cause higher corneal rigidity and produce more overestimation of NCT measurement, while they have stronger capillary attraction of the precorneal tear film for the GAT tip and also produce overestimation of GAT measurement. As a result, [NCT/GAT] was believed to be not influenced by the corneal curvature.

  9. The Influence of Corneal Thickness and Curvature on the Difference Between Intraocular Pressure Measurements Obtained with a Non-contact Tonometer and Those with a Goldmann Applanation Tonometer.

    Matsumoto; Makino; Uozato; Saishin; Miyamoto

    2000-11-01

    Purpose: The influence of corneal thickness and curvature on the difference between intraocular pressure (IOP) measurements obtained with a non-contact tonometer (NCT) and those with a Goldmann applanation tonometer (GAT) was studied.Methods: The corneal thickness and curvature were obtained in 230 eyes of 115 subjects. The correlation between them and ratios of measurement with NCT to that with GAT ([NCT/GAT]) were examined.Results: [NCT/GAT] and corneal thickness showed a significant positive correlation (r = 0.556, P <.01), but, the correlation between [NCT/GAT] and the radius of corneal curvature was not statistically significant (r = -0.035, P =.30).Conclusion: The thick cornea has more influence on the measurement with NCT than GAT, because IOP is measured with NCT over a wider applanation area. The corneas with steeper curvature also cause higher corneal rigidity and produce more overestimation of NCT measurement, while they have stronger capillary attraction of the precorneal tear film for the GAT tip and also produce overestimation of GAT measurement. As a result, [NCT/GAT] was believed to be not influenced by the corneal curvature.

  10. Corneal Laceration

    Full Text Available ... by something sharp flying into the eye. It can also be caused by something striking the eye ... If the corneal laceration is deep enough it can cause a full thickness laceration. This is when ...

  11. The central corneal light reflex ratio from photographs derived from a digital camera in young adults.

    Duangsang, Suampa; Tengtrisorn, Supaporn

    2012-05-01

    To determine the normal range of Central Corneal Light Reflex Ratio (CCLRR) from photographs of young adults. A digital camera equipped with a telephoto lens with a flash attachment placed directly above the lens was used to obtain corneal light reflex photographs of 104 subjects, first with the subject fixating on the lens of the camera at a distance of 43 centimeters, and then while looking past the camera to a wall at a distance of 5.4 meters. Digital images were displayed using Adobe Photoshop at a magnification of l200%. The CCLRR was the ratio of the sum of distances between the inner margin of cornea and the central corneal light reflex of each eye to the sum of horizontal corneal diameter of each eye. Measurements were made by three technicians on all subjects, and repeated on a 16% (n=17) subsample. Mean ratios (standard deviation-SD) from near/distance measurements were 0.468 (0.012)/0.452 (0.019). Limits of the normal range, with 95% certainty, were 0.448 and 0.488 for near measurements and 0.419 and 0.484 for distance measurements. Lower and upper indeterminate zones were 0.440-0.447 and 0.489-0.497 for near measurements and 0.406-0.418 and 0.485-0.497 for distance measurements. More extreme values can be considered as abnormal. The reproducibility and repeatability of the test was good. This method is easy to perform and has potential for use in strabismus screening by paramedical personnel.

  12. Genomic locus modulating corneal thickness in the mouse identifies POU6F2 as a potential risk of developing glaucoma.

    Rebecca King

    2018-01-01

    Full Text Available Central corneal thickness (CCT is one of the most heritable ocular traits and it is also a phenotypic risk factor for primary open angle glaucoma (POAG. The present study uses the BXD Recombinant Inbred (RI strains to identify novel quantitative trait loci (QTLs modulating CCT in the mouse with the potential of identifying a molecular link between CCT and risk of developing POAG. The BXD RI strain set was used to define mammalian genomic loci modulating CCT, with a total of 818 corneas measured from 61 BXD RI strains (between 60-100 days of age. The mice were anesthetized and the eyes were positioned in front of the lens of the Phoenix Micron IV Image-Guided OCT system or the Bioptigen OCT system. CCT data for each strain was averaged and used to QTLs modulating this phenotype using the bioinformatics tools on GeneNetwork (www.genenetwork.org. The candidate genes and genomic loci identified in the mouse were then directly compared with the summary data from a human POAG genome wide association study (NEIGHBORHOOD to determine if any genomic elements modulating mouse CCT are also risk factors for POAG.This analysis revealed one significant QTL on Chr 13 and a suggestive QTL on Chr 7. The significant locus on Chr 13 (13 to 19 Mb was examined further to define candidate genes modulating this eye phenotype. For the Chr 13 QTL in the mouse, only one gene in the region (Pou6f2 contained nonsynonymous SNPs. Of these five nonsynonymous SNPs in Pou6f2, two resulted in changes in the amino acid proline which could result in altered secondary structure affecting protein function. The 7 Mb region under the mouse Chr 13 peak distributes over 2 chromosomes in the human: Chr 1 and Chr 7. These genomic loci were examined in the NEIGHBORHOOD database to determine if they are potential risk factors for human glaucoma identified using meta-data from human GWAS. The top 50 hits all resided within one gene (POU6F2, with the highest significance level of p = 10-6 for

  13. Accuracy of Corneal Thickness by Swept-Source Optical Coherence Tomography and Scheimpflug Camera in Virgin and Treated Fuchs Endothelial Dystrophy.

    Arnalich-Montiel, Francisco; Ortiz-Toquero, Sara; Auladell, Clara; Couceiro, Ana

    2018-06-01

    To assess intraobserver repeatability, intersession reproducibility, and agreement of swept-source Fourier-domain optical coherence tomography (SS-OCT) and the Scheimpflug camera in measuring corneal thickness in virgin and grafted eyes with Fuchs endothelial corneal dystrophy (FECD). Thirty-six control eyes, 35 FECD eyes, 30 FECD with corneal edema eyes, 25 Descemet stripping automated endothelial keratoplasty (DSAEK) eyes, and 29 Descemet membrane endothelial keratoplasty (DMEK) eyes were included. The apical center, pupillary center, and thinnest corneal thickness were determined in 3 consecutive images and repeated 2 weeks later. Repeatability and reproducibility coefficients, intraclass correlation coefficients, and 95% limits of agreement (LOA) between measurements were calculated. Agreement between devices was assessed using Bland-Altman analysis. Corneal thickness measurements were highly reproducible and repeatable with both systems. SS-OCT showed better repeatability in all corneal locations in the normal, FECD, FECD with edema, DSAEK, and DMEK groups (coefficient of variation ≤0.60%, ≤0.36%, ≤0.43%, ≤1.09%, and ≤0.48%, respectively) than the Scheimpflug (coefficient of variation ≤1.15%, ≤0.92%, ≤1.10%, ≤1.25%, and ≤1.14%, respectively). Between-session 95% LOA for SS-OCT was less than 3% for all groups except for the FECD with edema group, being almost double using the Scheimpflug camera. Differences between instruments were statistically significant in all groups and locations (P group (P ≤ 0.51); however, SS-OCT underestimated all measurements. SS-OCT provides better reproducible and repeatable measurements of corneal thickness than those obtained with the Scheimpflug camera in patients with FECD or an endothelial transplant. Variations between examinations higher than the 95% LOA observed in our study should raise awareness of changes in the endothelial function.

  14. Reproducibility of Corneal Graft Thickness measurements with COLGATE in patients who have undergone DSAEK (Descemet Stripping Automated Endothelial Keratoplasty

    Wong Melissa HY

    2012-08-01

    Full Text Available Abstract Background The CorneaL GrAft Thickness Evaluation (COLGATE system was recently developed to facilitate the evaluation of corneal graft thickness from OCT images. Graft thickness measurement can be a surrogate indicator for detecting graft failure or success. The purpose of this study was to determine the reproducibility of the COLGATE system in measuring DSAEK graft area between two observers. Methods This was a prospective case series in which 50 anterior segment OCT images of patients who had undergone DSAEK in either eye were analysed. Two observers (MW, AC independently obtained the image analysis for the graft area using both semi automated and automated method. One week later, each observer repeated the analysis for the same set of images. Bland-Altman analysis was performed to analyze inter and intra observer agreement. Results There was strong intraobserver correlation between the 2 semi automated readings obtained by both observers. (r = 0.936 and r = 0.962. Intraobserver ICC for observer 1 was 0.936 (95% CI 0.890 to 0.963 and 0.967 (95% CI 0.942 to 0.981 for observer 2. Likewise, there was also strong interobserver correlation (r = 0.913 and r = 0.969. The interobserver ICC for the first measurements was 0.911 (95% CI 0.849 to 0.949 and 0.968 (95% CI 0.945 to 0.982 for the second. There was statistical difference between the automatic and the semi automated readings for both observers (p = 0.006, p = 0.003. The automatic readings gave consistently higher values than the semi automated readings especially in thin grafts. Conclusion The analysis from the COLGATE programme can be reproducible between different observers. Care must be taken when interpreting the automated analysis as they tend to over estimate measurements.

  15. Macular volume and central foveal thickness measurements in ...

    Objective: To determine macular volume and central foveal thickness measurements in normal eyes of healthy. Nigerian adults using Stratus optical coherence tomography. Subjects and Methods: Consenting 100 adults Nigerians with normal eyes were recruited and examined using Carl. Zeiss Stratus Optical Coherence ...

  16. Corneal endothelial cell density and morphology in healthy Turkish eyes.

    Arıcı, Ceyhun; Arslan, Osman Sevki; Dikkaya, Funda

    2014-01-01

    Purpose. To describe the normative values of corneal endothelial cell density, morphology, and central corneal thickness in healthy Turkish eyes. Methods. Specular microscopy was performed in 252 eyes of 126 healthy volunteers (M : F, 42 : 84). Parameters studied included mean endothelial cell density (MCD), mean cell area (MCA), coefficient of variation (CV) in cell size, percentage of hexagonal cells, and central corneal thickness (CCT). Results. The mean age of volunteers was 44.3 ± 13.5 (range, 20 to 70) years. There was a statistically significant decrease in MCD (P Filipino eyes and higher than that described in Indian, Thai, and Iranian eyes.

  17. Influence of corneal biomechanical properties on intraocular pressure differences between an air-puff tonometer and the Goldmann applanation tonometer.

    Tranchina, Laura; Lombardo, Marco; Oddone, Francesco; Serrao, Sebastiano; Schiano Lomoriello, Domenico; Ducoli, Pietro

    2013-01-01

    To estimate the influence of corneal properties on intraocular pressure (IOP) differences between an air-puff tonometer (NT530P; Nidek) and the Goldmann applanation tonometer (Haag-Streit). The influence of central corneal thickness (CCT), keratometry, and Ocular Response Analyzer (Reichert) measurements of corneal viscoelasticity [corneal hysteresis (CH) and corneal resistance factor (CRF)] on IOP differences between tonometers was evaluated. The CRF was calculated to be the best predictor of the differences in IOP readings between tonometers (r2=0.23; Ptonometers. Corneal resistance to applanation induced by either contact or noncontact tonometers was calculated to be the most determinant factor in influencing IOP differences between applanation tonometers.

  18. Reliability of Entire Corneal Thickness Mapping in Normal Post-Laser in situ Keratomileusis and Keratoconus Eyes Using Long Scan Depth Spectral Domain Optical Coherence Tomography.

    Xu, Zhe; Chen, Sisi; Yang, Chun; Huang, Shenghai; Shen, Meixiao; Wang, Yuanyuan

    2018-01-01

    To investigate the repeatability and reproducibility of mapping the entire corneal thickness using spectral domain optical coherence tomography (SD-OCT). Thirty normal eyes, 30 post-laser in situ keratomileusis (LASIK) surgery eyes, and 30 keratoconus eyes were analyzed. A custom-built long scan depth SD-OCT device was used to obtain entire corneal images. Ten-millimeter-diameter corneal thickness maps were generated by an automated segmentation algorithm. Intraclass correlation coefficients of repeatability (ICC1) and reproducibility (ICC2), and coefficients of repeatability (CoR1) and reproducibility (CoR2), were calculated to quantify the precision and accuracy of corneal pachymetry measurements using the Bland-Altman method. For SD-OCT measurements in healthy subjects, CoR1 and CoR2 were less than 5.00 and 5.53 μm. ICC1 and ICC2 were more than 0.997 and 0.996. For SD-OCT measurements in LASIK patients, CoR1 and CoR2 were less than 5.09 and 5.34 μm. ICC1 and ICC2 were more than 0.997 and 0.996. For SD-OCT measurements in keratoconus patients, CoR1 and CoR2 were less than 11.57 and 10.92 μm. ICC1 and ICC2 were more than 0.995 and 0.996. The measurements of corneal pachymetric mapping by long scan depth SD-OCT can be assessed over the entire corneal area with good repeatability and reproducibility. © 2017 S. Karger AG, Basel.

  19. Macular volume and central foveal thickness measurements in ...

    The mean macula volume was 6.79 + 0.392 µm3. It was 6.861 , 0.297 in males, 6.496 , 0.520 in females and was statistically higher in males than females (P = 0.000). The mean central foveal thickness (MCFT) was 149.58±32.470 µm. It was 154.49 ± 34.652 µm in males and 133.33 ± 15.315 µm in females. MCFT was ...

  20. Late onset corneal ectasia after LASIK surgery.

    Said, Ashraf; Hamade, Issam H; Tabbara, Khalid F

    2011-07-01

    To report late onset corneal ectasia following myopic LASIK. A retrospective cohort case series. Nineteen patients with late onset corneal ectasia following LASIK procedure were examined at The Eye Center, Riyadh, Saudi Arabia. Patients underwent LASIK for myopia with spherical equivalent ranging from -1.4 to -13.75 diopters. Age and gender, history of systemic or local diseases, and time of onset of corneal ectasia were recorded. Eye examination and corneal topographical analyses were done before and after LASIK surgery. Nineteen patients (29 eyes) with late onset corneal ectasia were identified from 1998 to 2008 in 13 male and six female patients. The mean follow-up period was 108 ± 23 months (range 72-144 months). No patient had pre-operative identifiable risk factors for corneal ectasia and the mean time of onset was 57 ± 24 months (range 24-120 months after LASIK). The pre-operative values included mean central pachymetry 553 ± 25 μm, mean keratometry reading of 42.9 ± 1.5 diopters, average oblique cylinder of 1.4 ± 1.2 diopters, posterior surface elevation of 26 ± 2.1 diopters, corneal flap thickness of 160 μm, mean spherical equivalent of -5.6 ± 3.6 diopters, and calculated residual corneal stromal bed thickness was 288 ± 35 μm. Three (5 eyes) patients developed ectasia after pregnancy. Three (4 eyes) patients developed corneal ectasia following severe adenoviral keratoconjunctivitis and had positive PCR for adenovirus type 8. Corneal ectasia may develop many years after LASIK surgery and symptoms could go undetected for some time. Pregnancy and adenoviral keratoconjunctivitis occurred post-operatively in six patients.

  1. Equine corneal stromal abscesses

    Henriksen, M. D. L.; Andersen, P. H.; Plummer, C. E.

    2013-01-01

    The last 30 years have seen many changes in the understanding of the pathogenesis and treatment of equine corneal stromal abscesses (SAs). Stromal abscesses were previously considered an eye problem related to corneal bacterial infection, equine recurrent uveitis, corneal microtrauma and corneal....... Medical and surgical treatments are now directed towards elimination of fungal and bacterial infections, reduction and replacement of diseased corneal stroma, and suppression of iridocyclitis. If the abscess and anterior uveitis do not respond satisfactorily to medical therapy, full thickness or split...

  2. Corneal topography

    Andersen, J.; Koch-Jensen, P.; Østerby, Ole

    1993-01-01

    The central corneal zone is depicted on keratoscope photographs using a small target aperture and a large object distance. Information on the peripheral area is included by employing a hemispherical target with a dense circular and radial pattern. On a 16 mm (R = 8 mm) reference steel sphere the ...

  3. Study on phototherapeutic keratotomy for bacterial corneal lesions in rabbit

    Xin Zhou

    2018-05-01

    Full Text Available AIM: To study the effect of phototherapeutic keratectomy(PTKon rabbit bacterial corneal ulcer model and explore the clinical potential of this method. METHODS: Totally 48 eyes from all the 24 New Zealand rabbits were inoculated with Staphylococcus aureus and bacterial corneal ulcer model was established successfully. At 1d after inoculation, 48 eyes were given levofloxacin eye drops when corneal ulcer was confirmed. Then slit lamp inspection and optical coherence tomography(OCTwere performed to measure the central corneal ulcer depth. All the rabbits right eyes were treated with PTK, as an observation group, left eyes were not treated as a control group. The eye section were observed by slit lamp and central thickness of corneal ulcer was measured by OCT at 3 and 7d after this operation. Rabbits were sacrificed and the cornea was removed for pathological section 7d later. RESULTS: The corneal ulcers in both groups had a tendency to heal, showing a decrease in ulcer area and smoothness of the surface. There was no significant difference in the depth of corneal ulcer between the observation group and the control group before PTK(t=0.706, P=0.484. The difference between the two groups of eyes at 3 and 7d after PTK was obviously(PCONCLUSION: PTK can effectively cure rabbit Staphylococcus aureus corneal ulcer and promote ulcer wound healing, which may be used for clinical treatment of patients with bacterial corneal lesions.

  4. Corneal Laceration

    Full Text Available ... Ophthalmology/Strabismus Ocular Pathology/Oncology Oculoplastics/Orbit Refractive ... Corneal Laceration Sections What Is Corneal Laceration? Corneal Laceration Symptoms What Causes ...

  5. The retinal nerve fibre layer thickness in glaucomatous hydrophthalmic eyes assessed by scanning laser polarimetry with variable corneal compensation in comparison with age-matched healthy children.

    Hložánek, Martin; Ošmera, Jakub; Ležatková, Pavlína; Sedláčková, Petra; Filouš, Aleš

    2012-12-01

    To compare the thickness of the retinal nerve fibre layer (RNFL) in hydrophthalmic glaucomatous eyes in children with age-matched healthy controls using scanning laser polarimetry with variable corneal compensation (GDxVCC). Twenty hydrophthalmic eyes of 20 patients with the mean age of 10.64 ± 3.02 years being treated for congenital or infantile glaucoma were included in the analysis. Evaluation of RNFL thickness measured by GDxVCC in standard Temporal-Superior-Nasal-Inferior-Temporal (TSNIT) parameters was performed. The results were compared to TSNIT values of an age-matched control group of 120 healthy children published recently as referential values. The correlation between horizontal corneal diameter and RNFL thickness in hydrophthalmic eyes was also investigated. The mean ± SD values in TSNIT Average, Superior Average, Inferior Average and TSNIT SD in hydrophthalmic eyes were 52.3 ± 11.4, 59.7 ± 17.1, 62.0 ± 15.6 and 20.0 ± 7.8 μm, respectively. All these values were significantly lower compared to referential TSNIT parameters of age-matched healthy eyes (p = 0.021, p = 0.001, p = 0.003 and p = 0.018, respectively). A substantial number of hydrophthalmic eyes laid below the level of 5% probability of normality in respective TSNIT parameters: 30% of the eyes in TSNIT average, 50% of the eyes in superior average, 30% of the eyes in inferior average and 45% of the eyes in TSNIT SD. No significant correlation between enlarged corneal diameter and RNFL thickness was found. The mean values of all standard TSNIT parameters assessed using GDxVCC in hydrophthalmic glaucomatous eyes in children were significantly lower in comparison with referential values of healthy age-matched children. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

  6. Comparison of stromal corneal nerves between normal and keratoconus patients using confocal microscopy.

    Ramírez Fernández, M; Hernández Quintela, E; Naranjo Tackman, R

    2014-08-01

    To evaluate the differences in stromal corneal nerves between normal patients and keratoconus patients. A total of 140 eyes of 70 normal patients (group A) and 122 eyes of 87 keratoconus patients (group B) were examined with the confocal microscope, with a central scan of the total corneal thickness being taken. The morphology and thickness of the corneal stromal nerves were evaluated by using the Navis v. 3.5.0. software. Nerve thickness was obtained from the mean between the widest and the narrowest portions of each stromal nerve. Corneal stromal nerves were observed as irregular linear hyper-reflective structures with wide and narrow portions in all cases. Mean corneal stromal nerves thickness in group A was 5.7±1.7 (range from 3.3 to 10.4 μ), mean corneal stromal nerves thickness in group B was 7.2±1.9 (range from 3.5 to 12.0 μ). There was a statistical significant difference (P<.05) in stromal corneal nerves thickness between group A and group B. Stromal corneal nerves morphology was similar in both groups, but stromal nerves were thicker in keratoconus patients. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  7. Recovery of Corneal Endothelial Cells from Periphery after Injury.

    Sang Ouk Choi

    Full Text Available Wound healing of the endothelium occurs through cell enlargement and migration. However, the peripheral corneal endothelium may act as a cell resource for the recovery of corneal endothelium in endothelial injury.To investigate the recovery process of corneal endothelial cells (CECs from corneal endothelial injury.Three patients with unilateral chemical eye injuries, and 15 rabbit eyes with corneal endothelial chemical injuries were studied. Slit lamp examination, specular microscopy, and ultrasound pachymetry were performed immediately after chemical injury and 1, 3, 6, and 9 months later. The anterior chambers of eyes from New Zealand white rabbits were injected with 0.1 mL of 0.05 N NaOH for 10 min (NaOH group. Corneal edema was evaluated at day 1, 7, and 14. Vital staining was performed using alizarin red and trypan blue.Specular microscopy did not reveal any corneal endothelial cells immediately after injury. Corneal edema subsided from the periphery to the center, CEC density increased, and central corneal thickness decreased over time. In the animal study, corneal edema was greater in the NaOH group compared to the control at both day 1 and day 7. At day 1, no CECs were detected at the center and periphery of the corneas in the NaOH group. Two weeks after injury, small, hexagonal CECs were detected in peripheral cornea, while CECs in mid-periphery were large and non-hexagonal.CECs migrated from the periphery to the center of the cornea after endothelial injury. The peripheral corneal endothelium may act as a cell resource for the recovery of corneal endothelium.

  8. Evaluation of Corneal Topography and Biomechanical Parameters after Use of Systemic Isotretinoin in Acne Vulgaris

    Yusuf Yildirim

    2014-01-01

    Full Text Available Purpose. We report the effect of isotretinoin on corneal topography, corneal thickness, and biomechanical parameters in patients with acne vulgaris. Method. Fifty-four eyes of 54 patients who received oral isotretinoin for treatment of acne vulgaris were evaluated. All patients underwent a corneal topographical evaluation with a Scheimpflug camera combined with Placido-disk (Sirius, ultrasonic pachymetry measurements, and corneal biomechanical evaluation with an ocular response analyzer at baseline, in the 1st, 3rd, and 6th months of treatment, and 6 months after isotretinoin discontinuation. Results. The thinnest corneal thickness measured with Sirius differed significantly in the 1st, 3rd, and 6th months compared with the baseline measurement; there was no significant change in ultrasonic central corneal thickness measurements and biomechanical parameters (corneal hysteresis and corneal resistance factor throughout the study. Average simulated keratometry and surface asymmetry index increased significantly only in the first month of treatment according to the baseline. All changes disappeared 6 months after the end of treatment. Conclusion. Basal tear secretion and corneal morphologic properties were significantly influenced during the systemic isotretinoin treatment and the changes were reversible after discontinuation. No statistical important biomechanical differences were found to be induced by isotretinoin.

  9. Intrastromal corneal ring implants for corneal thinning disorders: an evidence-based analysis.

    2009-01-01

    -graft rates in KC patients have been reported. Visual rehabilitation or recovery of visual acuity after transplant may be slow and/or unsatisfactory to patients. INTACS® (Addition Technology Inc. Sunnyvale, CA, formerly KeraVision, Inc.) are the only currently licensed corneal implants in Canada. The implants are micro-thin poly methyl methacrylate crescent shaped ring segments with a circumference arc length of 150 degrees, an external diameter of 8.10 mm, an inner diameter of 6.77 mm, and a range of different thicknesses. Implants act as passive spacers and, when placed in the cornea, cause local separation of the corneal lamellae resulting in a shortening of the arc length of the anterior corneal curvature and flattening the central cornea. Increasing segment thickness results in greater lamellar separation with increased flattening of the cornea correcting for myopia by decreasing the optical power of the eye. Corneal implants also improve corneal astigmatism but the mechanism of action for this is less well understood. Treatment with corneal implants is considered for patients who are contact lens intolerant, having adequate corneal thickness particularly around the area of the implant incision site and without central corneal scarring. Those with central corneal scarring would not benefit from implants and those without an adequate corneal thickness, particularly in the region that the implants are being inserted, would be at increased risk for corneal perforation. Patients desiring to have visual rehabilitation that does not include glasses or contact lenses would not be candidates for corneal ring implants. Placement of the implants is an outpatient procedure with topical anesthesia generally performed by either corneal specialists or refractive surgeons. It involves creating tunnels in the corneal stroma to secure the implants either by a diamond knife or laser calibrated to an approximate depth of 70% of the cornea. Variable approaches have been employed by

  10. Changes in corneal sensitivity following cross-linking for progressive early-stage keratoconus

    Anelise de Medeiros Lago

    2014-04-01

    Full Text Available Purpose: To evaluate changes in corneal sensitivity following corneal cross-linking (CXL in patients with progressive earlier stage keratoconus. Methods: Thirty-eight eyes of 19 patients (11 women, 8 men were included in a prospective, nonrandomized clinical study. The mean patient age was 22 years (range, 18-26 years. Inclusion criteria were early stage bilateral progressive keratoconus, a transparent cornea, and a thickness of ≥440 µm in the thinnest area of the cornea. Using the Cochet-Bonnet esthesiometer, central corneal sensitivity was measured before surgery, 7 days after surgery, and once a month thereafter until recovery of baseline preoperative levels. Central corneal sensitivity >40 mm was considered normal. Results: Corneal sensitivity gradually returned to preoperative levels in all treated eyes. The mean central corneal sensitivity was 52.2, 24.0, 38.2, 42.5, 50.0, and 52.5 mm before surgery, 7 days after surgery, and at 1, 2, 3, and 4 months after surgery, respectively. Normal levels of corneal sensation, but not baseline (preoperative levels, were observed 2 months after surgery. The preoperative levels were observed 3 months after surgery. Conclusions: Our results suggest that central corneal sensitivity can be decreased for as long as 3 months after CXL for progressive earlier stage keratoconus.

  11. Corneal Laceration

    Full Text Available ... Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye ... Causes Corneal Laceration? Corneal Laceration Diagnosis Corneal Laceration Treatment What Is Corneal Laceration? Leer en Español: ¿Qué ...

  12. Assessment of Corneal and Tear Film Parameters in Rheumatoid Arthritis Patients Using Anterior Segment Spectral Domain Optical Coherence Tomography.

    El-Fayoumi, Dina; Youssef, Maha Mohamed; Khafagy, Mohamed Mahmoud; Badr El Dine, Nashwa; Gaber, Wafaa

    2018-01-01

    To study the corneal changes in rheumatoid arthritis (RA) patients in vivo, using spectral domain anterior segment optical coherence tomography (AS-OCT). A case-control study was done on 43 RA patients and 40 controls. The disease activity score (DAS28-ESR) was calculated and all participants had lower tear meniscus, corneal thickness, and epithelial thickness evaluation using AS-OCT. The lower tear meniscus height (LTMH) and the lower tear meniscus area (LTMA) were significantly lower in the RA patients than in controls (p < 0.001). RA patients also had a significantly thinner central corneal thickness (p = 0.02) and their epithelium was found to be thinner in the superotemporal peripheral sector. The LTMH and LTMA are significantly reduced in RA patients, despite the absence of clinical diagnosis of dry eye. RA patients have thinner corneal thickness and epithelial thickness than controls, which did not correlate with either disease duration or activity.

  13. Analysis of corneal topography in patients with pure microphthalmia in Eastern China.

    Hu, Pei-Hong; Gao, Gui-Ping; Yu, Yao; Pei, Chong-Gang; Zhou, Qiong; Huang, Xin; Zhang, Ying; Shao, Yi

    2015-12-01

    To determine the typical corneal changes in pure microphthalmia using a corneal topography system and identify characteristics that may assist in early diagnosis. Patients with pure microphthalmia and healthy control subjects underwent corneal topography analysis (Orbscan IIZ® Corneal Topography System; Bausch and Lomb, Bridgewater, NJ, USA) to determine degree of corneal astigmatism (mean A), simulation of corneal astigmatism (sim A), mean keratometry (mean K), simulated keratometry (sim K), irregularities in the 3 - and 5-mm zone, and mean thickness of nine distinct corneal regions. Patients with pure microphthalmia (n = 12) had significantly higher mean K, sim K, mean A, sim A, 3.0 mm irregularity and 5.0 mm irregularity, and exhibited significantly more false keratoconus than controls (n = 12). There was a significant between-group difference in the morphology of the anterior corneal surface and the central curvature of the cornea. Changes in corneal morphology observed in this study could be useful in borderline situations to confirm the diagnosis of pure microphthalmia. © The Author(s) 2015.

  14. Corneal densitometry and its correlation with age, pachymetry, corneal curvature, and refraction.

    Garzón, Nuria; Poyales, Francisco; Illarramendi, Igor; Mendicute, Javier; Jáñez, Óscar; Caro, Pedro; López, Alfredo; Argüeso, Francisco

    2017-12-01

    To determine normative corneal densitometry values in relation to age, sex, refractive error, corneal thickness, and keratometry, measured using the Oculus Pentacam system. Three hundred and thirty-eight healthy subjects (185 men; 153 women) with no corneal disease underwent an exhaustive ocular examination. Corneal densitometry was expressed in standardized grayscale units (GSU). The mean corneal densitometry over the total area was 16.46 ± 1.85 GSU. The Pearson correlation coefficient for total densitometry was r = 0.542 (p  0.05). This is the first report of normative corneal densitometry values in relation to keratometry, corneal thickness, and spherical equivalent measured with the latest Oculus Pentacam software. Corneal densitometry increases with age, but corneal keratometry and refractive parameters do not affect light scattering in the human cornea.

  15. Animal study on transplantation of human umbilical vein endothelial cells for corneal endothelial decompensation

    Li Cui

    2014-06-01

    Full Text Available AIM: To explore the feasibility of culturing human umbilical vein endothelial cells(HUVECon acellular corneal stroma and performing the posterior lamellar endothelial keratoplasty(PLEKtreating corneal endothelial decompensation.METHODS: Thirty New-Zealand rabbits were divided into three groups randomly, 10 rabbits for experimental group, 10 for stroma group and 10 for control group. Corneal endothelial cells were removed to establish animal model of corneal endothelial failure. PLEK was performed on the rabbits of experimental group and stroma group, and nothing was transplantated onto the rabbits of control group with the deep layer excised only. Postoperative observation was taken for 3mo. The degree of corneal edema and central corneal thickness were recorded for statistical analysis.RESULTS: Corneas in experimental group were relieved in edema obviously compared with that in stroma group and the control group, and showed increased transparency 7d after the operation. The average density of endothelial cells was 2 026.4±129.3cells/mm2, and average central corneal thickness was 505.2±25.4μm in experimental group, while 1 535.6±114.5μm in stroma group and 1 493.5±70.2μm in control group 3mo after operation.CONCLUSION:We achieved preliminary success in our study that culturing HUVEC on acellular corneal stroma and performing PLEK for corneal endothelial decompensation. HUVEC transplanted could survive in vivo, and have normal biological function of keeping cornea transparent. This study provides a new idea and a new way clinically for the treatment of corneal endothelial diseases.

  16. The Favorable Effect of Mesenchymal Stem Cell Treatment on the Antioxidant Protective Mechanism in the Corneal Epithelium and Renewal of Corneal Optical Properties Changed after Alkali Burns

    Cejka, Cestmir; Holan, Vladimir; Trosan, Peter; Zajicova, Alena; Javorkova, Eliska; Cejkova, Jitka

    2016-01-01

    The aim of this study was to examine whether mesenchymal stem cells (MSCs) and/or corneal limbal epithelial stem cells (LSCs) influence restoration of an antioxidant protective mechanism in the corneal epithelium and renewal of corneal optical properties changed after alkali burns. The injured rabbit corneas (with 0.25 N NaOH) were untreated or treated with nanofiber scaffolds free of stem cells, with nanofiber scaffolds seeded with bone marrow MSCs (BM-MSCs), with adipose tissue MSCs (Ad-MSCs), or with LSCs. On day 15 following the injury, after BM-MSCs or LSCs nanofiber treatment (less after Ad-MSCs treatment) the expression of antioxidant enzymes was restored in the regenerated corneal epithelium and the expressions of matrix metalloproteinase 9 (MMP9), inducible nitric oxide synthase (iNOS), α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), and vascular endothelial factor (VEGF) were low. The central corneal thickness (taken as an index of corneal hydration) increased after the injury and returned to levels before the injury. In injured untreated corneas the epithelium was absent and numerous cells revealed the expressions of iNOS, MMP9, α-SMA, TGF-β1, and VEGF. In conclusion, stem cell treatment accelerated regeneration of the corneal epithelium, restored the antioxidant protective mechanism, and renewed corneal optical properties. PMID:27057279

  17. The Favorable Effect of Mesenchymal Stem Cell Treatment on the Antioxidant Protective Mechanism in the Corneal Epithelium and Renewal of Corneal Optical Properties Changed after Alkali Burns.

    Cejka, Cestmir; Holan, Vladimir; Trosan, Peter; Zajicova, Alena; Javorkova, Eliska; Cejkova, Jitka

    2016-01-01

    The aim of this study was to examine whether mesenchymal stem cells (MSCs) and/or corneal limbal epithelial stem cells (LSCs) influence restoration of an antioxidant protective mechanism in the corneal epithelium and renewal of corneal optical properties changed after alkali burns. The injured rabbit corneas (with 0.25 N NaOH) were untreated or treated with nanofiber scaffolds free of stem cells, with nanofiber scaffolds seeded with bone marrow MSCs (BM-MSCs), with adipose tissue MSCs (Ad-MSCs), or with LSCs. On day 15 following the injury, after BM-MSCs or LSCs nanofiber treatment (less after Ad-MSCs treatment) the expression of antioxidant enzymes was restored in the regenerated corneal epithelium and the expressions of matrix metalloproteinase 9 (MMP9), inducible nitric oxide synthase (iNOS), α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1), and vascular endothelial factor (VEGF) were low. The central corneal thickness (taken as an index of corneal hydration) increased after the injury and returned to levels before the injury. In injured untreated corneas the epithelium was absent and numerous cells revealed the expressions of iNOS, MMP9, α-SMA, TGF-β1, and VEGF. In conclusion, stem cell treatment accelerated regeneration of the corneal epithelium, restored the antioxidant protective mechanism, and renewed corneal optical properties.

  18. The Favorable Effect of Mesenchymal Stem Cell Treatment on the Antioxidant Protective Mechanism in the Corneal Epithelium and Renewal of Corneal Optical Properties Changed after Alkali Burns

    Cestmir Cejka

    2016-01-01

    Full Text Available The aim of this study was to examine whether mesenchymal stem cells (MSCs and/or corneal limbal epithelial stem cells (LSCs influence restoration of an antioxidant protective mechanism in the corneal epithelium and renewal of corneal optical properties changed after alkali burns. The injured rabbit corneas (with 0.25 N NaOH were untreated or treated with nanofiber scaffolds free of stem cells, with nanofiber scaffolds seeded with bone marrow MSCs (BM-MSCs, with adipose tissue MSCs (Ad-MSCs, or with LSCs. On day 15 following the injury, after BM-MSCs or LSCs nanofiber treatment (less after Ad-MSCs treatment the expression of antioxidant enzymes was restored in the regenerated corneal epithelium and the expressions of matrix metalloproteinase 9 (MMP9, inducible nitric oxide synthase (iNOS, α-smooth muscle actin (α-SMA, transforming growth factor-β1 (TGF-β1, and vascular endothelial factor (VEGF were low. The central corneal thickness (taken as an index of corneal hydration increased after the injury and returned to levels before the injury. In injured untreated corneas the epithelium was absent and numerous cells revealed the expressions of iNOS, MMP9, α-SMA, TGF-β1, and VEGF. In conclusion, stem cell treatment accelerated regeneration of the corneal epithelium, restored the antioxidant protective mechanism, and renewed corneal optical properties.

  19. Clinical evaluation of low vision and central foveal thickness in highly myopic cataract eyes after phacoemulsification

    Ji-Li Chen

    2015-07-01

    Full Text Available AIM:To retrospectively evaluate central foveal thickness in highly myopic eyes with best correct visual acuity(BCVAMETHODS: In this retrospective clinical study, we consecutively recruited 70 low highly myopic cataract subjects(70 eyesunderwent Phaco. Postoperative visits were performed at 1wk, 1 and 3mo. Postoperative BCVA were recorded and further divided into 2 groups with BCVARESULTS: The ratio of BCVAPr=-0.716, PCONCLUSION: In this study, BCVA is improved after 3mo follow up. There has significant correlation between postoperative BCVA and central foveal thickness.

  20. Long-term changes in subfoveal choroidal thickness and central macula thickness after Nd:YAG laser capsulotomy.

    Yilmaz, Tolga; Yilmaz, Ahu

    2017-08-01

    To evaluate changes in central macula thickness (CMT), subfoveal choroid thickness (SCT), and intraocular pressure (IOP) before and after neodymium:yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy. 42 eyes of 42 patients who underwent Nd:YAG laser capsulotomy were included in this prospective study. CMT, SCT, and IOP were evaluated preoperatively and at postoperative week 1 and postoperative months 1, 3, 6, and 12. CMT was 238.1 ± 27.6 μm (mean ± SD) preoperatively, then 239.7 ± 29.8, 241.3 ± 28.7, 242.7 ± 27.2, 238.8 ± 23.7, and 238.3 ± 21.7 μm at postoperative week 1 and months 1, 3, 6, and 12, respectively. SCT was 263.3 ± 21.6 μm preoperatively, and 265.5 ± 24.8, 266.2 ± 25.7, 267.1 ± 26.3, 269.1 ± 24.2, and 269.9 ± 21.4 μm at postoperative week 1 and months 1, 3, 6, and 12, respectively. There were no significant differences between preoperative and postoperative results for CMT, SCT, or IOP (all p > 0.05). Although there were slight changes in choroid thickness in the long term, treatment of posterior capsule opacification with a low-energy Nd:YAG laser is a safe procedure that increases visual acuity without creating a significant increase in IOP, CMT, and SCT.

  1. Determination of corneal elasticity coefficient using the ORA database.

    Avetisov, Sergei E; Novikov, Ivan A; Bubnova, Irina A; Antonov, Alexei A; Siplivyi, Vladimir I

    2010-07-01

    To propose a new approach for the study of corneal biomechanics using the Reichert Ocular Response Analyzer (ORA) database, which is based on changes in velocity retardation in the central cornea at the peak of flattening. The ORA applanation curve was analyzed using a mathematical technique, which allowed calculation of the elasticity coefficient (Ke), which is primarily characteristic of the elastic properties of the cornea. Elasticity coefficient values were obtained in patients with presumably different biomechanical properties of the cornea: "normal" cornea (71 eyes, normal group), keratoconus (34 eyes, keratoconus group), LASIK (36 eyes, LASIK group), and glaucoma with elevated and compensated intraocular pressure (lOP) (38 eyes, glaucoma group). The mean Ke value in the normal group was 11.05 +/- 1.6, and the corneal thickness correlation coefficient r2 was 0.48. In the keratoconus group, the mean Ke value was 4.91 +/- 1.87 and the corneal thickness correlation coefficient r2 was 0.47. In the LASIK group, Ke and r2 were 5.99 +/- 1.18 and 0.39, respectively. In the glaucoma group, the same eyes that experienced a two-fold reduction in lOP developed a statistically significant reduction in the Ke (1.06 times lower), whereas their corneal hysteresis value increased 1.25 times. The elasticity coefficient calculated using the ORA applanation curve can be used in the evaluation of corneal biomechanical properties.

  2. Distrofia corneal de Schnyder

    Michel Guerra Almaguer

    Full Text Available La principal entidad hereditaria con depósitos de lípidos en el estroma corneal es la distrofia cristalina central, conocida como distrofia de Schnyder, quien la describió en Suiza en 1927. Se caracteriza por depósitos blanco-amarillentos en el estroma corneal central y superficial. Se presenta un paciente de 28 años, del sexo masculino y piel negra, con antecedente de salud anterior. Acudió a consulta y refirió una disminución de la visión y cambio de coloración progresiva de ambos ojos, de años de evolución. En la exploración oftalmológica de ambos ojos se apreciaron lesiones blanquecinas anulares a nivel del estroma corneal, con ligera turbidez corneal central. Los estudios refractivos realizados constataron un astigmatismo hipermetrópico simple. El resto del examen oftalmológico fue negativo. Para el diagnóstico de certeza se empleó el microscopio confocal. Se concluye que el caso presenta una distrofia corneal estromal de tipo cristalina, de Schnyder.

  3. Full-Thickness Retinochoroidal Incision in the Management of Central Retinal Vein Occlusion

    San-Ni Chen

    2015-01-01

    Full Text Available Purpose. To evaluate the clinical outcomes in patients with central retinal vein occlusion (CRVO treated with full-thickness retinochoroidal incisions and to compare whether there is difference in treatment response in ischemic and nonischemic CRVO. Methods. Retrospective study of patients of CRVO receiving full-thickness retinochoroidal incisions in Changhua Christian Hospital. Fluorescein angiography (FA, slit-lamp biomicroscopy, indirect funduscopy, best corrected visual acuity, and central macular thickness (CMT measured by optical coherence tomography were performed pre- and postoperatively. Patients were divided into an ischemic and nonischemic group according to the findings of FA. Patients were followed up for at least 1 year. Results. Twenty-eight eyes (14 ischemic and 14 nonischemic CRVO were included. Functional retinochoroidal venous anastomosis (RCVA was achieved in 48 of the 65 retinochoroidal incisions (73.8%. Central macular thickness (CMT and retinal hemorrhage decreased significantly after the surgery. Significant visual gain was observed postoperatively in the nonischemic group, but not in the ischemic group. Postoperative complications included vitreous hemorrhage (17.8%, neovascular glaucoma (7.1%, and preretinal fibrovasular membrane (10.7%, all of which were in the ischemic group. Conclusions. RCVA formation induced by retinochoroidal incisions could improve venous flow, and decrease CMT and retinal hemorrhage. However, only eyes with nonischemic CRVO showed visual improvement.

  4. Cortical thickness difference across the central sulcus visualized in the presence of vasogenic edema

    Togao, Osamu; Yoshiura, Takashi; Mihara, Futoshi; Noguchi, Tomoyuki; Hiwatashi, Akio; Yamashita, Koji; Yoshitake, Tadamasa; Honda, Hiroshi

    2008-01-01

    Purpose: To confirm the cortical thickness difference across the central sulcus (CS) visualized in the presence of vasogenic edema on MRI. Materials and methods: T2-weighted images of 70 cerebral hemispheres showing vasogenic edema infiltrating into subcortical white matter around the CS were studied retrospectively. Two neuroradiologists measured the cortical thickness of the anterior and posterior banks of the CS, precentral sulci (PrCS), and postcentral sulci (PoCS). Additionally, we compared the cortical thickness of the anterior and posterior banks of each sulcus visually using a grading scale. Results: On T2-weighted images, the cerebral cortex was highlighted by a high signal-intensity vasogenic edema in the adjacent white matter, and its thickness was readily measurable. The unique cortical thickness difference between the anterior and posterior banks of the CS were confirmed with measurements of 2.67 and 1.48 mm (p < 0.0001). The cortical measurements across other cerebral sulci were 2.04 and 1.95 mm (NS) for the PrCS, and 1.67 and 1.77 mm (NS) for the PoCS. The cortical thickness ratios were 1.86 for the CS, 1.05 for the PrCS, and 0.96 for the PoCS. On visual evaluation, the anterior bank of the CS was thicker than the posterior bank in 93% (65/70). For the PrCS and PoCS, the thickness of the anterior and posterior banks appeared to be equal in over 70% of the patients. Conclusion: A prominent cortical thickness difference across the CS in the presence of vasogenic edema was confirmed. This finding is considered to facilitate the identification of the CS in patients with brain tumors

  5. Cortical thickness difference across the central sulcus visualized in the presence of vasogenic edema

    Togao, Osamu [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582 (Japan)], E-mail: togao@dr.hosp.kyushu-u.ac.jp; Yoshiura, Takashi; Mihara, Futoshi; Noguchi, Tomoyuki; Hiwatashi, Akio; Yamashita, Koji; Yoshitake, Tadamasa; Honda, Hiroshi [Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582 (Japan)

    2008-05-15

    Purpose: To confirm the cortical thickness difference across the central sulcus (CS) visualized in the presence of vasogenic edema on MRI. Materials and methods: T2-weighted images of 70 cerebral hemispheres showing vasogenic edema infiltrating into subcortical white matter around the CS were studied retrospectively. Two neuroradiologists measured the cortical thickness of the anterior and posterior banks of the CS, precentral sulci (PrCS), and postcentral sulci (PoCS). Additionally, we compared the cortical thickness of the anterior and posterior banks of each sulcus visually using a grading scale. Results: On T2-weighted images, the cerebral cortex was highlighted by a high signal-intensity vasogenic edema in the adjacent white matter, and its thickness was readily measurable. The unique cortical thickness difference between the anterior and posterior banks of the CS were confirmed with measurements of 2.67 and 1.48 mm (p < 0.0001). The cortical measurements across other cerebral sulci were 2.04 and 1.95 mm (NS) for the PrCS, and 1.67 and 1.77 mm (NS) for the PoCS. The cortical thickness ratios were 1.86 for the CS, 1.05 for the PrCS, and 0.96 for the PoCS. On visual evaluation, the anterior bank of the CS was thicker than the posterior bank in 93% (65/70). For the PrCS and PoCS, the thickness of the anterior and posterior banks appeared to be equal in over 70% of the patients. Conclusion: A prominent cortical thickness difference across the CS in the presence of vasogenic edema was confirmed. This finding is considered to facilitate the identification of the CS in patients with brain tumors.

  6. Corneal Laceration

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Corneal Laceration ... Laceration Treatment What Is Corneal Laceration? Leer en Español: ¿Qué es una laceración de la córnea? Written ...

  7. Corneal Transplantation

    Hjortdal, Jesper Østergaard

    with less risk of rejection episodes. Besides covering updated chapters on penetrating keratoplasty, and anterior and posterior lamellar procedures, this textbook also gives a thorough overview of the history of corneal transplantation and a detailed presentation of the microstructural components...... and to assist fellows and corneal surgeons in their advice and selection of patients for the best surgical procedure considering benefi ts and risks....

  8. A case of unilateral circumscribed posterior keratoconus evaluated by three different imaging tools: optical coherence tomography, videokeratography, and Scheimpflug corneal tomography.

    Spadea, Leopoldo; Maraone, Giorgia; Cagini, Carlo

    2017-02-01

    Posterior keratoconus is a rare corneal anomaly which is part of the ectatic corneal disorders. We report a clinical presentation of a unilateral posterior keratoconus in a 42-year-old man. At the time of presentation, corrected distance visual acuity (CDVA) was 20/20 with a correction of +2.50 +2.50 × 90° in the right eye and 20/40 with +1 +3.00 × 105° in the left eye. Slit lamp microscopy showed in the left eye an evidence of corneal thinning with a mild anterior protrusion and a remarkable posterior excavation. The intraocular pressure was 19 mmHg in right eye and 16 mmHg in left eye. Ultrasound pachymetry showed a minimum corneal thickness of 556 μ in right eye and 289 μ in left eye. The anterior segment optical coherence tomography (AS-OCT) revealed central corneal thinning and showed a reduced epithelial thickness. Videokeratography showed an increase of the corneal curvature in a defined area with central steepening in the area of the posterior corneal depression with gradual paracentral flattening. The description of this case underlines the importance of this instruments such us AS-OCT and corneal topography in diagnosis of posterior keratoconus. It can also be observed that in the contralateral eye there are no signs of ectasia as in the rare condition of unilateral keratoconus.

  9. Corneal Epithelial Remodeling and Its Effect on Corneal Asphericity after Transepithelial Photorefractive Keratectomy for Myopia

    Jie Hou

    2016-01-01

    Full Text Available Purpose. To evaluate the changes in epithelial thickness profile following transepithelial photorefractive keratectomy (T-PRK for myopia and to investigate the effect of epithelial remodeling on corneal asphericity. Methods. Forty-four patients (44 right eyes who underwent T-PRK were retrospectively evaluated. Epithelial thickness was measured using spectral-domain optical coherence tomography at different corneal zones (central, 2 mm; paracentral, 2–5 mm; and mid-peripheral, 5-6 mm preoperatively and at 1 week and 1, 3, and 6 months postoperatively. The correlation between the changes in corneal epithelial thickness (ΔCET and postoperative Q-value changes (ΔQ was analyzed 6 months postoperatively. Results. Epithelial thickness at 6 months showed a negative meniscus-like lenticular pattern with less central thickening, which increased progressively toward the mid-periphery (3.69±4.2, 5.19±3.8, and 6.23±3.9 μm at the center, paracenter, and mid-periphery, resp., P<0.01. A significant positive relationship was observed between epithelial thickening and ΔQ 6 months postoperatively (r=0.438, 0.580, and 0.504, resp., P<0.01. Conclusions. Significant epithelial thickening was observed after T-PRK and showed a lenticular change with more thickening mid-peripherally, resulting in increased oblateness postoperatively. Epithelial remodeling may modify the epithelial thickness profile after surface ablation refractive surgery for myopia.

  10. In Vivo Corneal Biomechanical Properties with Corneal Visualization Scheimpflug Technology in Chinese Population

    Ying Wu

    2016-01-01

    Full Text Available Purpose. To determine the repeatability of recalculated corneal visualization Scheimpflug technology (CorVis ST parameters and to study the variation of biomechanical properties and their association with demographic and ocular characteristics. Methods. A total of 783 healthy subjects were included in this study. Comprehensive ophthalmological examinations were conducted. The repeatability of the recalculated biomechanical parameters with 90 subjects was assessed by the coefficient of variation (CV and intraclass correlation coefficient (ICC. Univariate and multivariate linear regression models were used to identify demographic and ocular factors. Results. The repeatability of the central corneal thickness (CCT, deformation amplitude (DA, and first/second applanation time (A1/A2-time exhibited excellent repeatability (CV% ≤ 3.312% and ICC ≥ 0.929 for all measurements. The velocity in/out (Vin/out, highest concavity- (HC- radius, peak distance (PD, and DA showed a normal distribution. Univariate linear regression showed a statistically significant correlation between Vin, Vout, DA, PD, and HC-radius and IOP, CCT, and corneal volume, respectively. Multivariate analysis showed that IOP and CCT were negatively correlated with Vin, DA, and PD, while there was a positive correlation between Vout and HC-radius. Conclusion. The ICCs of the recalculated parameters, CCT, DA, A1-time, and A2-time, exhibited excellent repeatability. IOP, CCT, and corneal volume significantly influenced the biomechanical properties of the eye.

  11. Granular corneal dystrophy

    Castillo Pérez, Alexeide de la C; Vilches Lescaille, Daysi; Noriega, Justo Luis; Martínez Balido, Daneel; León Balbón, Bárbaro Ramón; León Bernal, Danysleidi

    2015-01-01

    Las distrofias corneales constituyen un conjunto de enfermedades que presentan, en su mayoría, una baja incidencia y se caracterizan por acúmulo de material hialino o amiloide que disminuyen la transparencia corneal. La distrofia granular es una enfermedad autosómica dominante que presenta opacidades grises en el estroma superficial central de la córnea y se hacen visibles en la primera y segunda décadas de la vida, lo que provoca disminución de la visión más significativa cerca de los 40 año...

  12. Influence of corneal parameters in keratoconus on IOP readings obtained with different tonometers.

    Firat, Penpe Gul; Orman, Gozde; Doganay, Selim; Demirel, Soner

    2013-03-01

    Accurate intraocular pressure (IOP) measurement is important but of unsure reliability in patients with keratoconus. Different types and models of tonometers are available. This study investigated the influence of corneal parameters on IOP readings obtained by a Goldmann applanation tonometer, a non-contact tonometer and a dynamic contour tonometer. IOP readings with the Goldmann applanation, non-contact and dynamic contour tonometers were obtained from 52 patients with keratoconus and from 50 normal subjects and their corneal parameters were measured using a Pentacam. The mean IOP measurements in keratoconus obtained with the Goldmann applanation, non-contact and dynamic contour tonometers were statistically significantly different from the mean IOP measurements in the normal subjects (p contact tonometers but not on the dynamic contour tonometer. In the control group, thinnest and central corneal thicknesses had a significant effect on findings with the Goldmann and non-contact tonometers but not on the dynamic contour tonometer. The corneal volume (CV) had no significant effect on the three tonometers in both groups. The corneal parameters affecting the IOP readings of the Goldmann applanation tonometers, non-contact tonometers and the dynamic contour tonometers are not the same. While the Goldmann applanation and non-contact tonometers were significantly affected by the corneal parameters that were measured, the dynamic contour tonometer was not affected by any of these corneal parameters. © 2013 The Authors. Clinical and Experimental Optometry © 2013 Optometrists Association Australia.

  13. On the correlation between minimum thickness and central deflection during small punch test

    Kumar, Pradeep; Chattopadhyay, J.; Dutta, B.K.

    2016-01-01

    Present paper deals with a detailed study on the correlation between minimum thickness (t/t_0) and central deflection (δ/t_0). Such data are obtained during the deformation of a small punch test of miniaturized specimen. Finite element studies have been carried out to investigate the effect of various parameters which are expected to influence this correlation. The parameters under consideration are material hardening, material yield stress, coefficient of friction and initial thickness of the specimen. It is shown that the correlation remains unaffected with respect to change in material parameters. Similarly, the coefficient of friction beyond 0.2 also does not affect the correlation. However, change in thickness has significant effect on the correlation. A modification has been suggested in the existing correlation to consider the influence of thickness change. The modified correlation is then used to calculate fracture toughness using the experimental results quoted in the literature. It is shown that the modified correlation improves the fracture toughness prediction considerably.

  14. Corneal Laceration

    Full Text Available ... to Full Corneal Transplantation Nov 29, 2016 Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry ...

  15. Preliminary study of the correlation between refractive error and corneal refractive power, corneal asphericity in myopic eye

    Qi-Chao Han

    2014-05-01

    Full Text Available AIM: To investigate the correlation between myopic refractive error and relative factors, including the corneal refractive power, posterior refractive power, axial length, corneal asphericity coefficient Q value, central cornea thickness(CCTand intraocular pressure(IOP. METHODS:According to the degree of myopia measured by subjective refraction, 138 myopia patients were divided into three subgroups: mild group(-1.00D--3.00D, moderate group(-3.25D--6.00D, high group(>6.00D. The Pentacam anterior segment tomographer(Germany, Oculus Companywas used to measure the corneal refractive power, posterior refractive power, and corneal asphericity in the right eye. IOP, CCT and axial length were measured by a non-contact tonometer and A-scan ultrasonic, respectively. The data was analyzed with a Pearson correlation analysis and one-way ANOVA. RESULTS: The myopic refractive error was negatively correlated with the axial length(r=-0.682, Pr=0.009, P=0.925. The axial length was negatively correlated with corneal refractive power(r=-0.554, Pr=0.674, Pr=-0.375, P=0.01. There was no significantly correlation between the myopic refractive error and CCT, IOP(r=-0.138, P=0.141; r=-0.121, P=0.157. CONCLUSION:The corneal refractive power plays the role of emmetropization during the development of myopia. There is clinic significance for the correlation between Q value and refractive error, IOP to guide the corneal refractive surgery.

  16. Tissue and cellular biomechanics during corneal wound injury and repair.

    Raghunathan, Vijay Krishna; Thomasy, Sara M; Strøm, Peter; Yañez-Soto, Bernardo; Garland, Shaun P; Sermeno, Jasmyne; Reilly, Christopher M; Murphy, Christopher J

    2017-08-01

    Corneal wound healing is an enormously complex process that requires the simultaneous cellular integration of multiple soluble biochemical cues, as well as cellular responses to the intrinsic chemistry and biophysical attributes associated with the matrix of the wound space. Here, we document how the biomechanics of the corneal stroma are altered through the course of wound repair following keratoablative procedures in rabbits. Further we documented the influence that substrate stiffness has on stromal cell mechanics. Following corneal epithelial debridement, New Zealand white rabbits underwent phototherapeutic keratectomy (PTK) on the right eye (OD). Wound healing was monitored using advanced imaging modalities. Rabbits were euthanized and corneas were harvested at various time points following PTK. Tissues were characterized for biomechanics with atomic force microscopy and with histology to assess inflammation and fibrosis. Factor analysis was performed to determine any discernable patterns in wound healing parameters. The matrix associated with the wound space was stiffest at 7days post PTK. The greatest number of inflammatory cells were observed 3days after wounding. The highest number of myofibroblasts and the greatest degree of fibrosis occurred 21days after wounding. While all clinical parameters returned to normal values 400days after wounding, the elastic modulus remained greater than pre-surgical values. Factor analysis demonstrated dynamic remodeling of stroma occurs between days 10 and 42 during corneal stromal wound repair. Elastic modulus of the anterior corneal stroma is dramatically altered following PTK and its changes coincide initially with the development of edema and inflammation, and later with formation of stromal haze and population of the wound space with myofibroblasts. Factor analysis demonstrates strongest correlation between elastic modulus, myofibroblasts, fibrosis and stromal haze thickness, and between edema and central corneal

  17. Altered corneal biomechanical properties in children with osteogenesis imperfecta.

    Lagrou, Lisa M; Gilbert, Jesse; Hannibal, Mark; Caird, Michelle S; Thomas, Inas; Moroi, Sayoko E; Bohnsack, Brenda L

    2018-04-07

    To evaluate biomechanical corneal properties in children with osteogenesis imperfecta (OI). A prospective, observational, case-control study was conducted on children 6-19 years of age diagnosed with OI. Patients with OI and healthy control subjects underwent complete ophthalmic examinations. Additional tests included Ocular Response Analyzer (ORA) and ultrasonic pachymetry. Primary outcomes were central corneal thickness (CCT), corneal hysteresis (CH), and corneal resistance factor (CRF). Intraocular pressure (IOP) was measured directly by either iCare or Goldmann applanation and indirectly by the ORA (Goldmann-correlated and corneal-compensated IOP). Statistically significant differences between OI and control groups were determined using independent samples t test. A total of 10 of 18 OI cases (mean age, 13 ± 4.37 years; 8 males) and 30 controls (mean age, 12.76 ± 2.62 years; 16 males) were able to complete the corneal biomechanics and pachymetry testing. Children with OI had decreased CH (8.5 ± 1.0 mm Hg vs 11.6 ± 1.2 mm Hg [P < 0.001]), CRF (9.0 ± 1.9 mm Hg vs 11.5 ± 1.5 [P < 0.001]) and CCT (449.8 ± 30.8 μm vs 568 ± 47.6 μm [P < 0.001]) compared to controls. The corneal-compensated IOP was significantly higher in OI cases (18.8 ± 3.1 mm Hg) than in controls (15.0 ± 1.6 mm Hg, P < 0.004), but there was no significant difference in Goldmann-correlated IOP (16.3 ± 4.2 mm Hg vs 15.8 ± 2.2 mm Hg). Collagen defects in OI alter corneal structure and biomechanics. Children with OI have decreased CH, CRF, and CCT, resulting in IOPs that are likely higher than measured by tonometry. These corneal alterations are present at a young age in OI. Affected individuals should be routinely screened for glaucoma and corneal pathologies. Copyright © 2018 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  18. Corneal Endothelial Alterations in Chronic Renal Failure.

    Sati, Alok; Jha, Ashok; Moulick, P S; Shankar, Sandeep; Gupta, Sandeep; Khan, M A; Dogra, Manu; Sangwan, Virender S

    2016-10-01

    To evaluate the corneal endothelial changes in patients with chronic renal failure. A total of 128 corneas of 128 subjects were studied, and 3 groups were formed. The first, the dialyzed group, composed of 32 corneas of 32 patients; the second, the nondialyzed group, composed of 34 corneas of 34 patients; and the third, the age-matched control group, composed of 64 corneas of 64 healthy subjects were examined by a specular microscope and the endothelial parameters were compared. The dialyzed group (enhanced level of toxins in the blood) was further analyzed to assess the influence of blood urea, serum creatinine, serum calcium, and serum phosphorus including the duration of dialysis on corneal endothelium. On comparing the 3 groups using analysis of variance and posthoc tests, a significant difference was found in the central corneal thickness (CCT) and endothelial cell density (CD) between the control (CCT: 506 ± 29 μm, CD: 2760 ± 304 cells/mm) and dialyzed groups (CCT: 549 ± 30 μm, CD: 2337 ± 324 cells/mm) [P chronic renal failure, more marked in patients undergoing hemodialysis and with raised blood urea level.

  19. Corneal backscatter in insulin-dependent and non-insulin-dependent diabetes mellitus patients: a pilot study

    Ana M Calvo-Maroto

    Full Text Available ABSTRACT Purpose: To compare central corneal backscatter obtained from Scheimpflug images between patients with insulin-dependent and non-insulin-dependent diabetes mellitus (IDDM and NIDDM, respectively and healthy controls. Methods: Seven patients with IDDM (7 eyes, eleven patients with NIDDM (11 eyes, and sixteen healthy subjects (16 eyes were included in this pilot study. Scheimpflug imaging system (Pentacam, Oculus Inc., Germany was used to obtain optical sections of the cornea. Seven meridians were analyzed for each eye, oriented from 70° to 110°. Optical density values for the central 3-mm and 5-mm zones of the cornea were obtained by image analysis using external software. Results: Corneal backscatter was significantly higher in the diabetic patients than in the controls for the central 3-mm (p=0.016 and 5-mm (p=0.014 zones. No significant differences in corneal backscatter were found between the IDDM and NIDDM groups for either zone (both p>0.05. In the NIDDM group, significant correlations were observed for both central zones between corneal backscatter and age (3 mm: r=0.604, p=0.025; 5 mm: r=0.614, p=0.022 and central corneal thickness (3 mm: r=0.641, p=0.017; 5 mm: r=0.671, p=0.012; this was not found in the IDDM group (p>0.05. The presence of diabetes showed a significant effect on central corneal backscatter (Kruskal-Wallis test, p<0.001. Conclusions: Diabetic patients showed higher values of corneal light backscatter than healthy subjects. Corneal optical density analysis may be a useful tool for monitoring and assessing the ocular changes caused by diabetes.

  20. Corneal endothelial morphology and function after torsional and longitudinal ultrasound mode phacoemulsification.

    Módis, László Jr; Szalai, Eszter; Flaskó, Zsuzsa; Németh, Gábor

    2016-01-01

    To study the endothelial cell morphology and corneal thickness changes after phacoemulsification by using the OZil torsional and longitudinal ultrasound techniques (Infiniti Vision System, Alcon Laboratories). Department of Ophthalmology, Clinical Center, University of Debrecen, Debrecen, Hungary. 52 patients with cataract were randomly assigned to longitudinal ultrasound and torsional mode group. All surgeries were performed through a 2.2 mm clear corneal incision, the method employed being divide and conquer. The endothelial morphometry such as cell density (ECD), mean cell area, coefficient of variation of cell area, and central corneal thickness were examined with specular microscopy (EM-1000, Tomey) preoperatively and 4, 8 weeks postoperatively. ECD values decreased significantly in both surgical groups (P .05). No significant correlation was found between the endothelial cell loss and the nucleus density. Both phacoemulsification techniques were safe and effective. The torsional handpiece performs oscillatory movements and delivers less energy into the eye than the longitudinal ultrasound technique, therefore providing more favorable energy and thermal safety profile.

  1. Thick sedimentary sequence around Bahraich in the northern part of the central Ganga foreland basin

    Manglik, A.; Adilakshmi, L.; Suresh, M.; Thiagarajan, S.

    2015-06-01

    We present the results of a magnetotelluric study along a 285 km long profile between Hamirpur and Rupadia (Nepal border) across the central Ganga basin. The electrical resistivity image obtained by combining 1-D Occam inversion models for 39 sites reveals a significant contrast in the subsurface structure from south to north along the profile. At the southern end, the Bundelkhand massif is delineated as a high resistivity block buried beneath 250-300 m thick sediments. The thickness of sediments gradually increases to about 500-600 m at Kanpur, and to about 1.2 km at Lucknow. Here, the basement depth increases to more than 2.5 km within a profile distance of 20 km, which could be attributed to the Lucknow fault. The underlying rocks also have moderate resistivity and possibly represent the Vindhyans. The sedimentary sequence at the northern end of the profile around Bahraich is more than 9 km thick. Integrating the resistivity image with a published seismic velocity structure from the region and the lithology from the 3927 m deep Matera-I well reveals that the top 4 km succession is constituted of highly conductive Oligocene and younger rocks of the Matera Formation and the Siwaliks, and recent sediments whereas the underlying > 5 km section is composed of sedimentary rocks of the Bahraich Group overlying the Archean basement. The high conductivity of sediments in conjunction with the low seismic velocity and large Vp/Vs obtained by receiver function analysis implies poor consolidation of sediments and thus high seismic hazard potential. The present results have implications for hydrocarbon exploration, hazard potential scenario of the central Ganga basin, and flexural strength of the Indian Plate.

  2. Correlating Corneal Biomechanics and Ocular Biometric Properties with Lamina Cribrosa Measurements in Healthy Subjects.

    Pérez Bartolomé, Francisco; Martínez de la Casa, Jose María; Camacho Bosca, Irene; Sáenz-Francés, Federico; Aguilar Munoa, Soledad; Martín Juan, Alberto; Garcia-Feijoo, Julian

    2018-01-01

    To examine interrelations between corneal biomechanics, ocular biometric variables and optic disc size (ODS), lamina cribosa depth (LCD) or thickness (LCT) in a healthy population. In a cross-sectional case-control study, the following measurements were made in 81 eyes of 81 participants: axial length, anterior chamber depth, lens thickness, and central corneal thickness using the optical biometer Lenstar LS900; and corneal hysteresis (CH), corneal resistance factor (CRF), Goldman-correlated intraocular pressure (IOPg), and corneal-compensated IOP (IOPcc) using the Ocular Response Analyzer. Serial horizontal enhanced depth imaging optical coherence tomography (EDI OCT) B-scans of the optic nerve head were obtained in each participant. Mean ODS, mean LCD, and mean LCT were measured in 11 equally spaced horizontal B-scans, excluding the LC insertion area under Bruch's membrane and scleral rim. LCD was measured in 74 of 81 eyes (91.36%); LCT in 60/81 (75.3%); ODS in 81/81 (100%). CRF was poorly, but significantly, correlated with LCT (Pearson's R = 0.264; P = 0.045). IOPcc, IOPg, CH, and ocular biometrics variables were poorly (non-significantly) correlated with LCD, LCT, and ODS. CRF was poorly but directly correlated with LCT. No association was detected between CH or ocular biometric variables and ODS, LCD, or LCT.

  3. Applications of corneal topography and tomography: a review.

    Fan, Rachel; Chan, Tommy Cy; Prakash, Gaurav; Jhanji, Vishal

    2018-03-01

    Corneal imaging is essential for diagnosing and management of a wide variety of ocular diseases. Corneal topography is used to characterize the shape of the cornea, specifically, the anterior surface of the cornea. Most corneal topographical systems are based on Placido disc that analyse rings that are reflected off the corneal surface. The posterior corneal surface cannot be characterized using Placido disc technology. Imaging of the posterior corneal surface is useful for diagnosis of corneal ectasia. Unlike corneal topographers, tomographers generate a three-dimensional recreation of the anterior segment and provide information about the corneal thickness. Scheimpflug imaging is one of the most commonly used techniques for corneal tomography. The cross-sectional images generated by a rotating Scheimpflug camera are used to locate the anterior and posterior corneal surfaces. The clinical uses of corneal topography include, diagnosis of corneal ectasia, assessment of corneal astigmatism, and refractive surgery planning. This review will discuss the applications of corneal topography and tomography in clinical practice. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

  4. Analysis of low-energy and high-frequency femtosecond laser for the construction of deep anterior donor corneal lamellae

    Gustavo Victor

    2014-04-01

    Full Text Available Purpose: To evaluate the efficacy and reliability of a low-energy femtosecond laser with a high repetition rate for construction of deep anterior donor corneal lamellae. Methods: This was a prospective laboratory investigation. Twenty-five human corneal buttons were femtosecond laser cut to create thick anterior lamellae (diameter, 10mm; thickness, 500µm. The laser cuts were made using an LDV® femtosecond laser in a Ziemer® anterior chamber. To obtain a better edge, the lamellae were trephined with an 8mm trephine (Katena®. The central corneal thickness and the anterior lamellae were measured using a Mitutoyo® thickness gauge with an accuracy of 0.001mm. Results: The central thickness of the 25 corneas ranged from 500 to 705µm (mean, 584 ± 51µm. The thickness of the anterior lamellae ranged from 420 to 480µm (mean, 455 ± 12.7µm. The anterior lamellae diameters were 7.90 ± 0.1mm, and all laser cuts were round. The lamellar interfaces appeared regular by surgical microscopy. There were no cases of inter-lamellar adhesion. Conclusion: The LDV® femtosecond laser appears to be a safe and reliable instrument for cutting deep anterior lamellae from donor corneoscleral buttons. Minimal variation in donor lamellar depth with the laser will be useful for creating donor corneal tissue for deeper anterior lamellar keratoplasty or endothelial keratoplasty surgery or both from a single donor cornea.

  5. Grosor corneal central y conteo de células endoteliales en pacientes sometidos a cirugía de catarata asistida con láser de femtosegundos comparada con cirugía facoemulsificación tradicional

    Georgina Givaudan Pedroza

    2016-09-01

    Conclusiones: Aunque se observó una diferencia estadísticamente significativa en cuanto al tiempo efectivo de faco, siendo menor en el grupo de femtosegundos, no se encontraron diferencias estadísticamente significativas en el CCE y grosor corneal central entre el grupo de facoemulsificación convencional y el asistido por láser de femtosegundos.

  6. Estudio comparativo de la medición del poder corneal central usando el queratómetro manual, el IOLMaster® y el tomógrafo Sirius®

    Manuel Garza-León

    2016-05-01

    Conclusiones: Para la evaluación de córneas sin enfermedad, la medición del poder queratométrico corneal central con los 3 equipos mostró una alta repetibilidad, sin embargo no hubo una concordancia y la diferencia entre los equipos fue estadísticamente significativa.

  7. Short-term corneal changes with gas-permeable contact lens wear in keratoconus subjects: a comparison of two fitting approaches.

    Romero-Jiménez, Miguel; Santodomingo-Rubido, Jacinto; Flores-Rodríguez, Patricia; González-Méijome, Jose-Manuel

    2015-01-01

    To evaluate changes in anterior corneal topography and higher-order aberrations (HOA) after 14-days of rigid gas-permeable (RGP) contact lens (CL) wear in keratoconus subjects comparing two different fitting approaches. Thirty-one keratoconus subjects (50 eyes) without previous history of CL wear were recruited for the study. Subjects were randomly fitted to either an apical-touch or three-point-touch fitting approach. The lens' back optic zone radius (BOZR) was 0.4mm and 0.1mm flatter than the first definite apical clearance lens, respectively. Differences between the baseline and post-CL wear for steepest, flattest and average corneal power (ACP) readings, central corneal astigmatism (CCA), maximum tangential curvature (KTag), anterior corneal surface asphericity, anterior corneal surface HOA and thinnest corneal thickness measured with Pentacam were compared. A statistically significant flattening was found over time on the flattest and steepest simulated keratometry and ACP in apical-touch group (all p<0.01). A statistically significant reduction in KTag was found in both groups after contact lens wear (all p<0.05). Significant reduction was found over time in CCA (p=0.001) and anterior corneal asphericity in both groups (p<0.001). Thickness at the thinnest corneal point increased significantly after CL wear (p<0.0001). Coma-like and total HOA root mean square (RMS) error were significantly reduced following CL wearing in both fitting approaches (all p<0.05). Short-term rigid gas-permeable CL wear flattens the anterior cornea, increases the thinnest corneal thickness and reduces anterior surface HOA in keratoconus subjects. Apical-touch was associated with greater corneal flattening in comparison to three-point-touch lens wear. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  8. Thickness of Knox Group overburden on Central Chestnut Ridge, Oak Ridge Reservation

    Staub, W.P.; Hopkins, R.A.

    1984-05-01

    The thickness of residual soil overlying the Knox Group along Central Chestnut Ridge was estimated by a conventional seismic refraction survey. The purpose of this survey was to identify sites on the Department of Energy's Oak Ridge Reservation where ample overburden exists above the water table for the shallow land burial of low-level radioactive waste. The results of the survey suggest that the upper slopes of the higher ridges in the area have a minimum of 16 to 26 m (52 to 85 ft) of overburden and that the crests of these ridges may have more than 30 m (100 ft). Therefore, it is unlikely that sound bedrock would be encountered during trench excavation [maximum of 10 m (32 ft)] along Central Chestnut Ridge. Also, the relatively low seismic wave velocities measured in the overburden suggest that the water table is generally deep. On the basis of these preliminary results, Central Chestnut Ridge appears to be suitable for further site characterization for the shallow land burial of low-level radioactive waste. 3 references, 5 figures, 1 table

  9. Comparison of 120- and 140-μm SMILE Cap Thickness Results in Eyes With Thick Corneas.

    Liu, Manli; Zhou, Yugui; Wu, Xianghua; Ye, Tiantian; Liu, Quan

    2016-10-01

    To evaluate clinical outcomes after small incision lenticule extraction (SMILE) with different cap thicknesses in thick corneas. Forty patients with central corneal thickness of more than 560 μm were recruited in this prospective, randomized, masked, paired-eye study. Patients were randomized to receive SMILE with a 120-μm cap thickness in 1 eye and 140-μm cap thickness in the other. Uncorrected and corrected distance visual acuity (CDVA), contrast sensitivity (CS), higher-order aberrations (HOAs), and morphologic modifications of corneal architecture were measured during the 3-month follow-up period. Postoperative refractive outcomes, visual outcomes, CS, and the changes in HOAs were similar between both groups. The persistence of brightly reflective particles in the corneal interface layer was 1388.6 ± 219.5/mm in eyes with 120-μm cap thickness and 54.7 ± 8.6/mm in eyes with 140-μm cap thickness (P line at the interface layer almost disappeared in all eyes with 140-μm cap thickness, and it still persisted in 43% of the fellow eyes at 3 months postoperatively. The anterior surfaces of lenticules in the 140-μm cap thickness group exhibited more smoothness than in the 120-μm cap thickness group. There was a lower level corneal wound-healing response after SMILE with a 140-μm cap thickness than with a 120-μm cap thickness, although the thickness of cap creation did not affect visual outcomes by 3 months postoperatively.

  10. Assessment of corneal biomechanical parameters in myopes and emmetropes using the Corvis ST.

    Lee, Rachel; Chang, Robert T; Wong, Ian Y H; Lai, Jimmy S M; Lee, Jacky W Y; Singh, Kuldev

    2016-03-01

    Prior studies have demonstrated conflicting results regarding the relationship between corneal biomechanical properties and refractive error. Thus, the purpose of this study was to compare the corneal biomechanical parameters of myopes and emmetropes. Ninety-four subjects with varying degrees of myopia (aged 29 to 74 years, spherical equivalent [SE] -0.5 to -17.5 D) and 25 emmetropes (aged 19 to 75 years, SE: -0.5 to +0.5 D) presenting at the Queen Mary Hospital, Hong Kong were recruited sequentially for this prospective study. All patients were phakic with no history of coexisting ocular disease. The corneal biomechanical parameters of the right eye of each subject were analysed using the Corvis ST non-contact tonometer. Intraocular pressure (IOP) was measured using both the Corvis ST and the Topcon Non-Contact Tonometer CT-80. Refractive error was measured by non-cycloplegic subjective and objective refractometry. High myopes (SE greater than -6.00 D) demonstrated greater mean outward applanation velocities (p < 0.001) and peak distance measurements (p = 0.009) compared to both low to moderate myopes (SE -0.50 to -6.00 D) and emmetropes. Both outward applanation velocity and peak distance were moderately correlated with refractive error (p ≤ 0.001), strongly correlated with IOP and weakly correlated with central corneal thickness. There were no statistically significant differences in age, IOP or central corneal thickness among emmetropes, low to moderate myopes or high myopes. Within this study of Chinese subjects, high myopes demonstrate greater corneal mean outward applanation velocity on Corvis ST testing, than emmetropes. In particular, those with high myopia (SE greater than -6.00 D) show a distinct corneal biomechanical profile relative to those with either emmetropia or low to moderate myopia using the Corvis ST. © 2016 Optometry Australia.

  11. Changes in corneal structure with continuous wear of high-Dk soft contact lenses: a pilot study.

    González-Méijome, J M; González-Pérez, J; Cerviño, A; Yebra-Pimentel, E; Parafita, M A

    2003-06-01

    Despite numerous studies that have considered the effects of extended wear of high-Dk soft contact lenses on ocular physiology, little attention has been paid to the impact of such lenses on central or peripheral corneal thickness and curvature. The present study aims to report the time course of changes in corneal thickness and curvature that accompanies the 30-night continuous wear of new silicone hydrogel soft contact lenses in a neophyte population in a longitudinal study. Six subjects wore high-Dk lotrafilcon (Dk = 140) on a 30-night replacement schedule for 12 months. Only measurements from the right eye were considered for analysis. Topographical measurements of corneal thickness and curvature were taken. The same parameters were monitored for an additional period of 3 months after lens removal. An almost homogenous increase in corneal radius of curvature was detected for all the locations studied, being statistically significant for the 4-mm cord diameter area. This effect was associated with a progressive thinning effect for the central cornea, whereas midperipheral and peripheral areas did not display such a thinning effect during continuous wear. These effects were still evident for the central cornea 3 months after contact lens wear discontinuation. Continuous wear of high-Dk silicone hydrogel contact lenses is associated with clinically appreciable changes in topographical corneal curvature, whereas only a reduction in corneal thickness is appreciated in the central area. This effect seems to be a result of mechanical pressure induced by these hybrid hyperpermeable materials, characterized by a higher modulus of elasticity. The small sample size compromises the conclusions addressed from this study, and further work will be necessary to confirm the present results.

  12. Three-dimensional LASIK flap thickness variability: topographic central, paracentral and peripheral assessment, in flaps created by a mechanical microkeratome (M2 and two different femtosecond lasers (FS60 and FS200

    Kanellopoulos AJ

    2013-04-01

    Full Text Available A John Kanellopoulos,1,2 George Asimellis1 1Laservision.gr Institute, Athens, Greece; 2NYU Medical School, New York, USA Purpose: To evaluate programmed versus achieved laser-assisted in situ keratomileusis (LASIK flap central thickness and investigate topographic flap thickness variability, as well as the effect of potential epithelial remodeling interference on flap thickness variability. Patients and methods: Flap thickness was investigated in 110 eyes that had had bilateral myopic LASIK several years ago (average 4.5 ± 2.7 years; range 2–7 years. Three age-matched study groups were formed, based on the method of primary flap creation: Group A (flaps made by the Moria Surgical M2 microkeratome [Antony, France], Group B (flaps made by the Abbott Medical Optics IntraLase™ FS60 femtosecond laser [Santa Ana, CA, USA], and Group C (flaps made by the Alcon WaveLight® FS200 femtosecond laser [Fort Worth, TX, USA]. Whole-cornea topographic maps of flap and epithelial thickness were obtained by scanning high-frequency ultrasound biomicroscopy. On each eye, topographic flap and epithelial thickness variability was computed by the standard deviation of thickness corresponding to 21 equally spaced points over the entire corneal area imaged. Results: The average central flap thickness for each group was 138.33 ± 12.38 µm (mean ± standard deviation in Group A, 128.46 ± 5.72 µm in Group B, and 122.00 ± 5.64 µm in Group C. Topographic flap thickness variability was 9.73 ± 4.93 µm for Group A, 8.48 ± 4.23 µm for Group B, and 4.84 ± 1.88 µm for Group C. The smaller topographic flap thickness variability of Group C (FS200 was statistically significant compared with that of Group A (M2 (P = 0.004, indicating improved topographic flap thickness consistency – that is, improved precision – over the entire flap area affected. Conclusions: The two femtosecond lasers produced a smaller flap thickness and reduced variability than the mechanical

  13. Corneal Endothelial Cell Density and Morphology in Healthy Turkish Eyes

    Ceyhun Arıcı

    2014-01-01

    Full Text Available Purpose. To describe the normative values of corneal endothelial cell density, morphology, and central corneal thickness in healthy Turkish eyes. Methods. Specular microscopy was performed in 252 eyes of 126 healthy volunteers (M : F, 42 : 84. Parameters studied included mean endothelial cell density (MCD, mean cell area (MCA, coefficient of variation (CV in cell size, percentage of hexagonal cells, and central corneal thickness (CCT. Results. The mean age of volunteers was 44.3±13.5 (range, 20 to 70 years. There was a statistically significant decrease in MCD (P<0.001; correlation, −0.388 and percentage of hexagonal cells, (P<0.001; correlation, −0.199 with age. There was also a statistically significant increase in MCA (P<0.001; correlation, 0.363 with increasing age. There was no statistically significant difference in MCD, MCA, CV in cell size, percentage of hexagonal cells, and CCT between genders and there was also no significant difference in these parameters between fellow eyes of subjects. Conclusions. Normotive data for the endothelium in the Turkish population are reported. Endothelial cell density in the Turkish eyes is less than that described in the Japanese, American, Chinese, and Filipino eyes and higher than that described in Indian, Thai, and Iranian eyes.

  14. Corneal endothelial cell loss and corneal biomechanical characteristics after two-step sequential or combined phaco-vitrectomy surgery for idiopathic epiretinal membrane

    Hamoudi, Hassan; Christensen, Ulrik Correll; La Cour, Morten

    2017-01-01

    with non-contact specular microscopy. Pachymetry [central cornea thickness (CCT)], keratometry and cornea volume (CV) were measured with Pentacam Scheimpflug camera. Primary outcome was change in CED after 12 months; secondary outcomes were changes in CCT and CV after 12 months. RESULTS: Sixty-two eyes......PURPOSE: To assess the impact of sequential and combined surgery [cataract surgery and 23-gauge pars plana vitrectomy (PPV) with peeling] on corneal endothelium cell density (CED) and corneal biomechanical characteristics. METHODS: Phakic eyes with epiretinal membrane (ERM) were prospectively...... allocated to (i) cataract surgery and subsequent PPV (CAT group), (ii) PPV and subsequent cataract surgery (VIT group) or (iii) phacovitrectomy (COMBI group). Eyes were examined at baseline, 1 month after each surgery, and at 3 and 12 months follow-up. Corneal endothelium cell density (CED) was assessed...

  15. Corneal Endothelial Safety of Intracameral Preservative-free 1% Xylocaine

    Shah Alpesh

    2004-01-01

    Full Text Available Purpose : To evaluate the effect of intracameral preservative-free 1% xylocaine on the corneal endothelium as an adjuvant to topical anaesthesia during phacoemulsification and Acrysof foldable IOL implantation. Material & Methods: This is a prospective, controlled, randomised, double-masked study. 106 patients with soft to moderately dense (Grade 1-3 senile cataract and corneal endothelial cell density of >1500/mm2 were randomised to the xylocaine group (n=53 and control group(n=53. Central endothelial specular microscopy and ultrasound corneal pachymetry were performed preoperatively. On the first postoperative day the eyes were evaluated for corneal oedema and Descemet′s folds. Ultrasound corneal pachymetry was performed at 1, 3 and 12 months. Specular microscopy was performed at 3 and 12 months. Cell loss was expressed as a percentage of preoperative cell density. Six patients could not complete one year follow-up. Chi-square and paired t test (2 tail statistical tests were applied for analysis. Results: Four (7.54% patients in the xylocaine group and 5 (9.43% in the control group had a few Descemet′s folds associated with mild central stromal oedema. Corneal thickness increased from 549.3µ ± 37.2µ to 555.5µ ± 36.5µ in the xylocaine group and from 553.1µ ± 36.2µ to 559.3µ ± 40.5µ in the control group at the one-month postoperative visit. Thickness returned to the preoperative level in xylocaine group 549.6µ ± 34.5µ and control group 554.7µ ± 41.1µ at three months. (P=0.484 The percentage of cell loss was 4.47 ± 2.53% in the xylocaine group and 4.49 ± 3.09 % in the control group at one year. (P=0.97 Conclusion: Intracameral preservative-free 1% xylocaine does not appear to affect corneal endothelium adversely during phacoemulsification.

  16. Corneal biomechanical changes in diabetes mellitus and their influence on intraocular pressure measurements.

    Sahin, Afsun; Bayer, Atilla; Ozge, Gökhan; Mumcuoğlu, Tarkan

    2009-10-01

    To investigate possible corneal biomechanical changes in patients with diabetes mellitus and understand the influence of such changes on intraocular pressure measurements. The study group was composed of 120 eyes from 61 healthy control subjects and 81 eyes from 43 diabetic subjects. IOP was measured first with an ocular response analyzer (ORA) and subsequently with a Goldmann applanation tonometer (GAT). Central corneal thickness (CCT) was measured with an ultrasonic pachymeter attached to the ORA. Axial length (AL), anterior chamber depth (ACD), and keratometry readings were acquired with partial coherence laser interferometry during the same visit before all IOP and CCT determinations were made. Corneal hysteresis (CH) was found to be significantly lower in diabetic patients when compared with healthy control subjects (9.51 +/- 1.82 mm Hg vs. 10.41 +/- 1.66 mm Hg, P < 0.0001). There was no significant difference in terms of corneal resistance factor (CRF; P = 0.8). Mean CCT, GAT IOP, Goldmann-correlated IOP (IOPg), and corneal-compensated IOP (IOPcc) were significantly higher in diabetic patients than in healthy control subjects (P = 0.01 for CCT, P < 0.0001 for GAT IOP, IOPg, and IOPcc). Diabetes affects corneal biomechanics and results in lower CH values than those in healthy control subjects, which may cause clinically relevant high IOP measurements independent of CCT.

  17. [Effect of Acupuncture Therapy on Visceral Fat Thickness in Simple Central Obesity Patients].

    Zhang, Cui-yan; Yang, Li

    2015-12-01

    To evaluate the efficacy of acupuncture therapy in decreasing visceral fat thickness(VFT) in patients with simple central obesity. Sixty patients with simple central obesity (syndrome of stomach and intestinal excessive heat) were randomly divided into control and acupuncture groups. Patients of the control group were treated with diet control and physical exercise procedure (basic treatment) for 6 months, and those of the acupuncture group treated with basic treatment combined with acupuncture stimulation of main acupoints Shuifen (CV 9), Yinjiao (CV 7), and bilateral Tianshu (ST 25), Huaroumen (ST 24) and bilateral Wailing (ST 26), etc., in combination with electroacupuncture (EA, 50- 100 Hz, 1- 5 mA) of bilateral ST 25, CV 9 and CV 7 for 30 min, once every other day for 3 months. The VFT (1 cm above the umbilicus) was detected by using an ultrasonic diagnosis instrument, and the body mass index (BMI, body weight/height(2)), and waist circumfe-rence (WC) were measured before treatment, 3 and 6 months after the treatment, respectively. Following 3 and 6 months' treatment, the VFT, BMI and WC of both groups were significantly decreased (Pacupuncture group were significantly superior to those of the control group in lowering VFT [(51.5 ± 6.5) mm vs (48.3 ± 4.7) mm)] and WC [(88.2 ± 3.6)cm vs (85.9 ± 4.3)cm] 6 months' after the treatment (Pacupuncture groups in BMI fowllowing 6 months' treatment [(31.0 ± 4.3) vs (30.1 ± 3.2), P>0.05]. Acupuncture intervention combined with diet control and physical exercise can effectively decrease VFT and WC in simple central obesity patients. VFT is a sensitive and better parameter for evaluating the effect of obesity treatment.

  18. Does Dry Eye Affect Repeatability of Corneal Topography Measurements?

    Doğan, Aysun Şanal; Gürdal, Canan; Köylü, Mehmet Talay

    2018-04-01

    The purpose of this study was to assess the repeatability of corneal topography measurements in dry eye patients and healthy controls. Participants underwent consecutive corneal topography measurements (Sirius; Costruzione Strumenti Oftalmici, Florence, Italy). Two images with acquisition quality higher than 90% were accepted. The following parameters were evaluated: minimum and central corneal thickness, aqueous depth, apex curvature, anterior chamber volume, horizontal anterior chamber diameter, iridocorneal angle, cornea volume, and average simulated keratometry. Repeatability was assessed by calculating intra-class correlation coefficient. Thirty-three patients with dry eye syndrome and 40 healthy controls were enrolled to the study. The groups were similar in terms of age (39 [18-65] vs. 30.5 [18-65] years, p=0.198) and gender (M/F: 4/29 vs. 8/32, p=0.366). Intra-class correlation coefficients among all topography parameters within both groups showed excellent repeatability (>0.90). The anterior segment measurements provided by the Sirius corneal topography system were highly repeatable for dry eye patients and are sufficiently reliable for clinical practice and research.

  19. Does Dry Eye Affect Repeatability of Corneal Topography Measurements?

    Aysun Şanal Doğan

    2018-04-01

    Full Text Available Objectives: The purpose of this study was to assess the repeatability of corneal topography measurements in dry eye patients and healthy controls. Materials and Methods: Participants underwent consecutive corneal topography measurements (Sirius; Costruzione Strumenti Oftalmici, Florence, Italy. Two images with acquisition quality higher than 90% were accepted. The following parameters were evaluated: minimum and central corneal thickness, aqueous depth, apex curvature, anterior chamber volume, horizontal anterior chamber diameter, iridocorneal angle, cornea volume, and average simulated keratometry. Repeatability was assessed by calculating intra-class correlation coefficient. Results: Thirty-three patients with dry eye syndrome and 40 healthy controls were enrolled to the study. The groups were similar in terms of age (39 [18-65] vs. 30.5 [18-65] years, p=0.198 and gender (M/F: 4/29 vs. 8/32, p=0.366. Intra-class correlation coefficients among all topography parameters within both groups showed excellent repeatability (>0.90. Conclusion: The anterior segment measurements provided by the Sirius corneal topography system were highly repeatable for dry eye patients and are sufficiently reliable for clinical practice and research.

  20. Distrofia corneal granular

    Alexeide de la C Castillo Pérez

    Full Text Available Las distrofias corneales constituyen un conjunto de enfermedades que presentan, en su mayoría, una baja incidencia y se caracterizan por acúmulo de material hialino o amiloide que disminuyen la transparencia corneal. La distrofia granular es una enfermedad autosómica dominante que presenta opacidades grises en el estroma superficial central de la córnea y se hacen visibles en la primera y segunda décadas de la vida, lo que provoca disminución de la visión más significativa cerca de los 40 años de edad. Presentamos dos casos clínicos de distrofia granular en pacientes hermanos de diferentes sexos, quienes acudieron a la consulta y refirieron visión nublada. El estudio de la historia familiar nos ayuda en el correcto diagnóstico y la biomicroscopia constituye el elemento más importante.

  1. Corneal Deformation Response and Ocular Geometry: A Non-invasive Diagnostic Strategy in Marfan Syndrome

    Beene, Lauren C.; Traboulsi, Elias I.; Seven, Ibrahim; Ford, Matthew R.; Roy, Abhijit Sinha; Butler, Robert S.; Dupps, William J.

    2015-01-01

    Purpose To evaluate corneal air-puff deformation responses and ocular geometry as predictors of Marfan syndrome. Design Prospective observational clinical study Methods Sixteen investigator-derived, 4 standard Ocular Response Analyzer (ORA), and geometric variables from corneal tomography and optical biometry using Oculus Pentacam and IOL Master were assessed for discriminative value in Marfan syndrome, measuring right eyes of 24 control and 13 Marfan syndrome subjects. Area under the receiver operating characteristic (AUROC) curve was assessed in univariate and multivariate analyses Results Six investigator-derived ORA variables successfully discriminated Marfan syndrome. The best lone disease predictor was Concavity Min (Marfan syndrome 47.5 ± 20, control 69 ± 14, p = 0.003; AUROC = 0.80). Corneal hysteresis and corneal resistance factor were decreased (Marfan syndrome CH 9.45 ± 1.62, control CH 11.24 ± 1.21, p = 0.01; Marfan syndrome CRF 9.77 ± 1.65, control CRF 11.03 ± 1.72, p = 0.01) and corneas were flatter in Marfan syndrome (Marfan syndrome Kmean 41.25 ± 2.09 D, control Kmean 42.70 ± 1.81 D, p = 0.046). No significant differences were observed in central corneal thickness, axial eye length, or intraocular pressure. A multivariate regression model incorporating corneal curvature and hysteresis loop area (HLA) provided the best predictive value for Marfan syndrome (AUROC = 0.85). Conclusions This study describes novel biodynamic features of corneal deformation responses in Marfan syndrome, including increased deformation, decreased bending resistance, and decreased energy dissipation capacity. A predictive model incorporating HLA and corneal curvature shows greatest potential for non-invasive clinical diagnosis of Marfan syndrome. PMID:26432567

  2. Corneal Deformation Response and Ocular Geometry: A Noninvasive Diagnostic Strategy in Marfan Syndrome.

    Beene, Lauren C; Traboulsi, Elias I; Seven, Ibrahim; Ford, Matthew R; Sinha Roy, Abhijit; Butler, Robert S; Dupps, William J

    2016-01-01

    To evaluate corneal air-puff deformation responses and ocular geometry as predictors of Marfan syndrome. Prospective observational clinical study. Sixteen investigator-derived, 4 standard Ocular Response Analyzer (ORA), and geometric variables from corneal tomography and optical biometry using Oculus Pentacam and IOL Master were assessed for discriminative value in Marfan syndrome, measuring right eyes of 24 control and 13 Marfan syndrome subjects. Area under the receiver operating characteristic (AUROC) curve was assessed in univariate and multivariate analyses. Six investigator-derived ORA variables successfully discriminated Marfan syndrome. The best lone disease predictor was Concavity Min (Marfan syndrome 47.5 ± 20, control 69 ± 14, P = .003; AUROC = 0.80). Corneal hysteresis (CH) and corneal resistance factor (CRF) were decreased (Marfan syndrome CH 9.45 ± 1.62, control CH 11.24 ± 1.21, P = .01; Marfan syndrome CRF 9.77 ± 1.65, control CRF 11.03 ± 1.72, P = .01) and corneas were flatter in Marfan syndrome (Marfan syndrome Kmean 41.25 ± 2.09 diopter, control Kmean 42.70 ± 1.81 diopter, P = .046). No significant differences were observed in central corneal thickness, axial eye length, or intraocular pressure. A multivariate regression model incorporating corneal curvature and hysteresis loop area (HLA) provided the best predictive value for Marfan syndrome (AUROC = 0.85). This study describes novel biodynamic features of corneal deformation responses in Marfan syndrome, including increased deformation, decreased bending resistance, and decreased energy dissipation capacity. A predictive model incorporating HLA and corneal curvature shows greatest potential for noninvasive clinical diagnosis of Marfan syndrome. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. CD147 required for corneal endothelial lactate transport.

    Li, Shimin; Nguyen, Tracy T; Bonanno, Joseph A

    2014-06-26

    CD147/basigin is a chaperone for lactate:H(+) cotransporters (monocarboxylate transporters) MCT1 and MCT4. We tested the hypothesis that MCT1 and -4 in corneal endothelium contribute to lactate efflux from stroma to anterior chamber and that silencing CD147 expression would cause corneal edema. CD147 was silenced via small interfering ribonucleic acid (siRNA) transfection of rabbit corneas ex vivo and anterior chamber lenti-small hairpin RNA (shRNA) pseudovirus in vivo. CD147 and MCT expression was examined by Western blot, RT-PCR, and immunofluorescence. Functional effects were examined by measuring lactate-induced cell acidification, corneal lactate efflux, [lactate], central cornea thickness (CCT), and Azopt (a carbonic anhydrase inhibitor) sensitivity. In ex vivo corneas, 100 nM CD147 siRNA reduced CD147, MCT1, and MCT4 expression by 85%, 79%, and 73%, respectively, while MCT2 expression was unaffected. CD147 siRNA decreased lactate efflux from 3.9 ± 0.81 to 1.5 ± 0.37 nmol/min, increased corneal [lactate] from 19.28 ± 7.15 to 56.73 ± 8.97 nmol/mg, acidified endothelial cells (pHi = 6.83 ± 0.07 vs. 7.19 ± 0.09 in control), and slowed basolateral lactate-induced acidification from 0.0034 ± 0.0005 to 0.0012 ± 0.0005 pH/s, whereas apical acidification was unchanged. In vivo, CD147 shRNA increased CCT by 28.1 ± 0.9 μm at 28 days; Azopt increased CCT to 24.4 ± 3.12 vs. 12.0 ± 0.48 μm in control, and corneal [lactate] was 47.63 ± 6.29 nmol/mg in shCD147 corneas and 17.82 ± 4.93 nmol/mg in paired controls. CD147 is required for the expression of MCT1 and MCT4 in the corneal endothelium. Silencing CD147 slows lactate efflux, resulting in stromal lactate accumulation and corneal edema, consistent with lactate efflux as a significant component of the corneal endothelial pump. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  4. Crustal Structure and Mantle Transition Zone Thickness beneath the Central Mongolia from Teleseismic Receiver Functions

    He, J.; Wu, Q.; Gao, M.; Munkhuu, U.; Demberel, S. G.

    2013-12-01

    The Mongolian Plateau (northern Asia) is situated between the Gobi-Altai range and the Siberian craton. In order to understand the crustal and mantle structure environmental characteristics, we use the teleseismic data recorded by 69 broadband stations located in the Central Mongolia(103.5°-111.5°E, 42°-50°N). The teleseismic events are selected from the global earthquakes between Aug. 2011 and Dec. 2013 with magnitude >5.5and the epicentral distance range from 30° to 95° to the center of the network. Lateral variations of the crustal thicknesses H and Vp/Vs ratios are obtained by using receiver function method. The crust thins gradually from northwest to southeast in the studying field. We found that the thinnest crust is ~37.5km in the southeast which is Gobi. The distribution of Vp/Vs ratios are between 1.68 and 1.84, which shows the heterogeneity. There are three high-anomaly areas: the Gobi range which is the Later Paleozoic Orogeny; the Khentei Mountains which is in the Jurassic-Cretaceous Reactive Continental Margin; the northwest area which is granite. Our research not only reveals the powerful evident of the crustal formation and evolution mechanism, but also provides some constraints on the mechanism of uplift of the Mongolian Plateau.This study was supported by the international cooperation project of the Ministry of Science and Technology of China (2011DFB20120).

  5. Comparative Evaluation of the Corneal and Anterior Chamber Parameters Derived From Scheimpflug Imaging in Arab and South Asian Normal Eyes.

    Prakash, Gaurav; Srivastava, Dhruv; Avadhani, Kavitha; Thirumalai, Sandeep M; Choudhuri, Sounak

    2015-11-01

    To evaluate the differences in the normal corneal and anterior segment Scheimpflug parameters in Arab and South Asian eyes. This hospital-based study was performed at a cornea and refractive surgery service in Abu Dhabi. A total of 600 consecutive normal candidates of South Asian (group 1, n = 300) and Arab (group 2, n = 300) origins underwent Scheimpflug imaging (Sirius; Costruzione Strumenti Oftalmici, Italy). One eye was randomly selected for evaluation. The age and sex distributions in both groups were comparable. The pachymetric variables were statistically higher in group 2 (group 2 vs. group 1, 544.3 ± 32.2 μm vs. 535.1 ± 31.4 μm for central corneal thickness, 541.0 ± 32.6 μm vs. 531.9 ± 31.5 μm for minimum corneal thickness, 571.7 ± 43.2 μm vs. 558.1 ± 42.3 μm for apical thickness, and 58.1 ± 4.2 vs. 57.3 ± 4.3 mm³ for the corneal volume; P Arab ethnicity tend to have statistically thicker and flatter corneas and less-crowded anterior segments than those of the South Asian counterparts. These epidemiological differences have a mild to moderate biological effect size (Cohen d), but they should be considered when evaluating these eyes for anterior segment or corneal procedures.

  6. Comparación de la medición del grosor corneal central medido con un nuevo equipo de tomografía con cámara de Scheimpflug y anillos de Plácido (Sirius® y paquimetría ultrasónica en sujetos sanos

    Manuel Garza-León

    2015-10-01

    Conclusiones: En la evaluación de córneas normales, la medición del grosor corneal central con ambos equipos mostró una alta repetibilidad y adecuada concordancia. Aunque la medición del grosor corneal central fue sistemáticamente más baja con el Sirius® que con el paquímetro ultrasónico, esta diferencia carece de significación clínica.

  7. Influence of eye biometrics and corneal micro-structure on noncontact tonometry.

    Danilo A Jesus

    Full Text Available Tonometry is widely used as the main screening tool supporting glaucoma diagnosis. Still, its accuracy could be improved if full knowledge about the variation of the corneal biomechanical properties was available. In this study, Optical Coherence Tomography (OCT speckle statistics are used to infer the organisation of the corneal micro-structure and hence, to analyse its influence on intraocular pressure (IOP measurements.Fifty-six subjects were recruited for this prospective study. Macro and micro-structural corneal parameters as well as subject age were considered. Macro-structural analysis included the parameters that are associated with the ocular anatomy, such as central corneal thickness (CCT, corneal radius, axial length, anterior chamber depth and white-to-white corneal diameter. Micro-structural parameters which included OCT speckle statistics were related to the internal organisation of the corneal tissue and its physiological changes during lifetime. The corneal speckle obtained from OCT was modelled with the Generalised Gamma (GG distribution that is characterised with a scale parameter and two shape parameters.In macro-structure analysis, only CCT showed a statistically significant correlation with IOP (R2 = 0.25, p<0.001. The scale parameter and the ratio of the shape parameters of GG distribution showed statistically significant correlation with IOP (R2 = 0.19, p<0.001 and R2 = 0.17, p<0.001, respectively. For the studied group, a weak, although significant correlation was found between age and IOP (R2 = 0.053, p = 0.04. Forward stepwise regression showed that CCT and the scale parameter of the Generalised Gamma distribution can be combined in a regression model (R2 = 0.39, p<0.001 to study the role of the corneal structure on IOP.We show, for the first time, that corneal micro-structure influences the IOP measurements obtained from noncontact tonometry. OCT speckle statistics can be employed to learn about the corneal micro

  8. Influence of eye biometrics and corneal micro-structure on noncontact tonometry.

    Jesus, Danilo A; Majewska, Małgorzata; Krzyżanowska-Berkowska, Patrycja; Iskander, D Robert

    2017-01-01

    Tonometry is widely used as the main screening tool supporting glaucoma diagnosis. Still, its accuracy could be improved if full knowledge about the variation of the corneal biomechanical properties was available. In this study, Optical Coherence Tomography (OCT) speckle statistics are used to infer the organisation of the corneal micro-structure and hence, to analyse its influence on intraocular pressure (IOP) measurements. Fifty-six subjects were recruited for this prospective study. Macro and micro-structural corneal parameters as well as subject age were considered. Macro-structural analysis included the parameters that are associated with the ocular anatomy, such as central corneal thickness (CCT), corneal radius, axial length, anterior chamber depth and white-to-white corneal diameter. Micro-structural parameters which included OCT speckle statistics were related to the internal organisation of the corneal tissue and its physiological changes during lifetime. The corneal speckle obtained from OCT was modelled with the Generalised Gamma (GG) distribution that is characterised with a scale parameter and two shape parameters. In macro-structure analysis, only CCT showed a statistically significant correlation with IOP (R2 = 0.25, p<0.001). The scale parameter and the ratio of the shape parameters of GG distribution showed statistically significant correlation with IOP (R2 = 0.19, p<0.001 and R2 = 0.17, p<0.001, respectively). For the studied group, a weak, although significant correlation was found between age and IOP (R2 = 0.053, p = 0.04). Forward stepwise regression showed that CCT and the scale parameter of the Generalised Gamma distribution can be combined in a regression model (R2 = 0.39, p<0.001) to study the role of the corneal structure on IOP. We show, for the first time, that corneal micro-structure influences the IOP measurements obtained from noncontact tonometry. OCT speckle statistics can be employed to learn about the corneal micro-structure and

  9. In-vivo corneal pulsation in relation to in-vivo intraocular pressure and corneal biomechanics assessed in-vitro. An animal pilot study.

    Rogala, Maja M; Danielewska, Monika E; Antończyk, Agnieszka; Kiełbowicz, Zdzisław; Rogowska, Marta E; Kozuń, Marta; Detyna, Jerzy; Iskander, D Robert

    2017-09-01

    The aim was to ascertain whether the characteristics of the corneal pulse (CP) measured in-vivo in a rabbit eye change after short-term artificial increase of intraocular pressure (IOP) and whether they correlate with corneal biomechanics assessed in-vitro. Eight New Zealand white rabbits were included in this study and were anesthetized. In-vivo experiments included simultaneous measurements of the CP signal, registered with a non-contact method, IOP, intra-arterial blood pressure, and blood pulse (BPL), at the baseline and short-term elevated IOP. Afterwards, thickness of post-mortem corneas was determined and then uniaxial tensile tests were conducted leading to estimates of their Young's modulus (E). At the baseline IOP, backward stepwise regression analyses were performed in which successively the ocular biomechanical, biometric and cardiovascular predictors were separately taken into account. Results of the analysis revealed that the 3rd CP harmonic can be statistically significantly predicted by E and central corneal thickness (Models: R 2  = 0.662, p biomechanics in-vitro was confirmed. In particular, spectral analysis revealed that higher amplitude and power of the 3rd CP harmonic indicates higher corneal stiffness, while the 1st CP harmonic correlates positively with the corresponding harmonic of the BPL signal. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Corneal Reinnervation and Sensation Recovery in Patients With Herpes Zoster Ophthalmicus: An In Vivo and Ex Vivo Study of Corneal Nerves.

    Cruzat, Andrea; Hamrah, Pedram; Cavalcanti, Bernardo M; Zheng, Lixin; Colby, Kathryn; Pavan-Langston, Deborah

    2016-05-01

    To study corneal reinnervation and sensation recovery in Herpes zoster ophthalmicus (HZO). Two patients with HZO were studied over time with serial corneal esthesiometry and laser in vivo confocal microscopy (IVCM). A Boston keratoprosthesis type 1 was implanted, and the explanted corneal tissues were examined by immunofluorescence histochemistry for βIII-tubulin to stain for corneal nerves. The initial central corneal IVCM performed in each patient showed a complete lack of the subbasal nerve plexus, which was in accordance with severe loss of sensation (0 of 6 cm) measured by esthesiometry. When IVCM was repeated 2 years later before undergoing surgery, case 1 showed a persistent lack of central subbasal nerves and sensation (0 of 6). In contrast, case 2 showed regeneration of the central subbasal nerves (4786 μm/mm) with partial recovery of corneal sensation (2.5 of 6 cm). Immunostaining of the explanted corneal button in case 1 showed no corneal nerves, whereas case 2 showed central and peripheral corneal nerves. Eight months after surgery, IVCM was again repeated in the donor tissue around the Boston keratoprosthesis in both patients to study innervation of the corneal transplant. Case 1 showed no nerves, whereas case 2 showed new nerves growing from the periphery into the corneal graft. We demonstrate that regaining corneal innervation and corneal function are possible in patients with HZO as shown by corneal sensation, IVCM, and ex vivo immunostaining, indicating zoster neural damage is not always permanent and it may recover over an extended period of time.

  11. Corneal laceration caused by river crab

    Vinuthinee N

    2015-01-01

    Full Text Available Naidu Vinuthinee,1,2 Anuar Azreen-Redzal,1 Jaafar Juanarita,1 Embong Zunaina2 1Department of Ophthalmology, Hospital Sultanah Bahiyah, Alor Setar, 2Department of Ophthalmology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia Abstract: A 5-year-old boy presented with right eye pain associated with tearing and photophobia of 1-day duration. He gave a history of playing with a river crab when suddenly the crab clamped his fingers. He attempted to fling the crab off, but the crab flew and hit his right eye. Ocular examination revealed a right eye corneal ulcer with clumps of fibrin located beneath the corneal ulcer and 1.6 mm level of hypopyon. At presentation, the Seidel test was negative, with a deep anterior chamber. Culture from the corneal scrapping specimen grew Citrobacter diversus and Proteus vulgaris, and the boy was treated with topical gentamicin and ceftazidime eyedrops. Fibrin clumps beneath the corneal ulcer subsequently dislodged, and revealed a full-thickness corneal laceration wound with a positive Seidel test and shallow anterior chamber. The patient underwent emergency corneal toileting and suturing. Postoperatively, he was treated with oral ciprofloxacin 250 mg 12-hourly for 1 week, topical gentamicin, ceftazidime, and dexamethasone eyedrops for 4 weeks. Right eye vision improved to 6/9 and 6/6 with pinhole at the 2-week follow-up following corneal suture removal. Keywords: corneal ulcer, pediatric trauma, ocular injury

  12. Overnight corneal swelling with high and low powered silicone hydrogel lenses.

    Moezzi, Amir M; Fonn, Desmond; Varikooty, Jalaiah; Simpson, Trefford L

    2015-01-01

    To compare central corneal swelling after eight hours of sleep in eyes wearing four different silicone hydrogel lenses with three different powers. Twenty-nine neophyte subjects wore lotrafilcon A (Dk, 140), balafilcon A (Dk, 91), galyfilcon A (Dk, 60) and senofilcon A (Dk, 103) lenses in powers -3.00, -10.00 and +6.00 D on separate nights, in random order, and on one eye only. The contra-lateral eye (no lens) served as the control. Central corneal thickness was measured using a digital optical pachometer before lens insertion and immediately after lens removal on waking. For the +6.00 D and -10.00 D, lotrafilcon A induced the least swelling and galyfilcon A the most. The +6.00 D power, averaged across lens materials, induced significantly greater central swelling than the -10.00 and -3.00 D (Re-ANOVA, p<0.001), (7.7±2.9% vs. 6.8±2.8% and 6.5±2.5% respectively) but there was no difference between -10.00 and -3.00 D. Averaged for power, lotrafilcon A induced the least (6.2±2.8%) and galyfilcon A the most (7.6±3.0%) swelling at the center (Re-ANOVA, p<0.001). Central corneal swelling with +6.00 D was significantly greater than -10.00 D lens power despite similar levels of average lens transmissibility of these two lens powers. The differences in corneal swelling of the lens wearing eyes are consistent with the differences in oxygen transmission of the silicone hydrogel lenses. In silicone hydrogel lenses central corneal swelling is mainly driven by central lens oxygen transmissibility. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  13. Analysis of biological characteristics of corneal endothelium in old patients with high myopia

    Ya-Qiong Chen

    2014-11-01

    Full Text Available AIM: To analyze quantitatively the biological characteristics of corneal endothelium in old patients of high myopia with non-contact automatic corneal endothelial microscope.METHODS:A total of 189 old patients(197 eyeswere divided into the high myopia group and the normal control group according to refractive diopter, in which the former 98 cases(103 eyes, the latter 91 cases(94 eyes. The hexagonal cell(6A, the coefficient of variation(CV, the average cell area(AVE, the average cell density(CDand the central corneal thickness(CCTwere measured by non-contact automatic corneal endothelium. SPSS 14.0 software was used to analyze their percentage. Z-test was used to compare the mean and Chi-square test was used to compare the rate in between. RESULTS: The average cell density in high myopia patients decreased, but there were 14 eyes >3 000/mm2, 11 eyes 2 and 78 eyes in the 2 000~3 000/mm2, there were each 0 eye, 3 eyes and 91 eyes respectively in the normal control group. There was statistically significant difference between high myopia group and control(χ2=19.11, PPP>0.05. CONCLUSION: There will provide a reference valuable for clinical surgeon. Because according to the changes of parameters and morphology of the corneal endothelial cells, we can understand the repair ability, to predict the consequence of the treatment, in order to determine the design and the choice of a surgical.

  14. Evaluation of corneal biomechanical properties following penetrating keratoplasty using ocular response analyzer

    Vanathi Murugesan

    2014-01-01

    Full Text Available Purpose: To evaluate corneal biomechanical properties in eyes that has undergone penetrating keratoplasty (PK. Materials and Methods: Retrospective observational study in a tertiary care centre. Data recorded included ocular response analyzer (ORA values of normal and post-keratoplasty eyes [corneal hysteresis (CH, corneal resistance factor (CRF, Goldmann-correlated intraocular pressure (IOPg, and cornea-compensated intraocular pressure (IOPcc], corneal topography, and central corneal thickness (CCT. Wilcoxon signed rank test was used to analyze the difference in ORA parameter between post-PK eyes and normal eyes. Correlation between parameters was evaluated with Spearman′s rho correlation. Results: The ORA study of 100 eyes of 50 normal subjects and 54 post-keratoplasty eyes of 51 patients showed CH of 8.340 ± 1.85 and 9.923 ± 1.558, CRF of 8.846 ± 2.39 and 9.577 ± 1.631 in post-PK eyes and normal eyes, respectively. CH and CRF did not correlate with post-keratoplasty astigmatism (P = 0.311 and 0.276, respectively while a significant correlation was observed with IOPg (P = 0.004 and IOPcc (P < 0.001. Conclusion: Biomechanical profiles were significantly decreased in post-keratoplasty eyes with significant correlation with higher IOP as compared with that in normal eyes.

  15. Influence of uncomplicated phacoemulsification on central macular thickness in diabetic patients: a meta-analysis.

    Jianping Liu

    Full Text Available To evaluate the effect of uncomplicated phacoemulsification on central macular thickness (CMT and best corrected visual acuity (BCVA in both diabetic patients without diabetic retinopathy (DR and diabetic patients with mild to moderate non-proliferative diabetic retinopathy (NPDR.Potential prospective observational studies were searched through PubMed and EMBASE. Standardized mean difference (SMD and 95% confidence interval (CI for changes in CMT and BCVA were evaluated at postoperative 1, 3 and 6 months. The pooled effect estimates were calculated in the use of a random-effects model.A total of 10 studies involving 190 eyes of diabetic patients without diabetic retinopathy and 143 eyes of diabetic patients with NPDR were identified. CMT values demonstrated a statistically significant increase after uncomplicated phacoemulsification at 1 month (SMD, -0.814; 95%CI, -1.230 to -0.399, 3 months (SMD, -0.565; 95%CI, -0.927 to -0.202 and 6 months (SMD, -0.458; 95%CI, -0.739 to -0.177 in diabetic patients with NPDR. There was no statistical difference in CMT values at postoperative 1 month (SMD, -1.206; 95%CI, -2.433 to 0.021and no statistically significant increase in CMT values at postoperative3 months (SMD, -0.535; 95%CI, -1.252 to 0.182 and 6 months (SMD, -1.181; 95%CI, -2.625 to 0.263 in diabetic patients without DR.BCVA was significantly increased at postoperative 1 month (SMD, 1.149; 95%CI, 0.251 to 2.047; and SMD,1.349; 95%CI, 0.264 to 2.434, respectively and 6 months (SMD, 1.295; 95%CI, 0.494 to 2.096; and SMD, 2.146; 95%CI, 0.172 to 4.120, respectively in both diabetic patients without DR and diabetic patients with NPDR. Sensitivity analysis showed that the results were relatively stable and reliable.Uncomplicated phacoemulsification in diabetic patients with mild to moderate NPDR seemed to influence significantly the subclinical thickening of the macular zones at postoperative 1, 3 and 6 months compared with diabetic patients without DR

  16. A study of corneal endothelial changes in soft contact lens wearers using non-contact specular microscopy

    Renu M Magdum

    2013-01-01

    Full Text Available Aim: To study the corneal endothelial changes after soft contact lens wear, to correlate these changes with the duration of soft contact lens wear, and to study the pattern of use and preferences of contact lens among young adults. Materials and Methods: This observational study was carried out in 100 eyes of 50 soft contact lens users aged between 19 and 27 years. Both eyes of 50 medical students who had never worn contact lenses served as controls. Data from each subject were collected using a structured questionnaire of 24 items that included demographic profile, pattern of contact lens use, symptoms, brand name, number of years worn, and hours of daily wear. These data were analyzed using Chi square for association. Specular microscopy was done using TOPCON SP-3000P. Computerized morphometry was used to evaluate central corneal thickness, size, shape, mean cellular density, hexagonality, coefficient of variation, and polymegathism of the corneal cells . Results: It was found that central corneal thickness was 0.532 ± 0.0309 mm in lens users and 0.514 ± 0.03 mm in controls, cell density was 2570.91 ± 432.06 cells/mm 2 in lens users and 2723.17 ± 327.64 cells/mm 2 in controls, while hexagonality was 54.81 ± 39.72% in lens users and 67.65 ± 36.49% in controls. Conclusion: Despite the known effects of long duration of soft contact lens use on corneal endothelial cell morphology, this study could not draw a significant correlation between them. However, a significant difference was found in the corneal endothelial thickness, cell density, and hexagonality. Among the soft contact lens users, 62% used soft disposable type while 38% used soft extended wear contact lens. Contact lenses were preferred over spectacles for better cosmetic appearance, comfort, and wider visual field.

  17. The effect of contact lens usage on corneal biomechanical parameters in myopic patients.

    Cankaya, Ali B; Beyazyildiz, Emrullah; Ileri, Dilek; Ozturk, Faruk

    2012-07-01

    To determine and compare the corneal biomechanical properties in myopic patients who use contact lenses and those who do not use contact lenses. The study consisted of 56 myopic patients who used contact lenses (study group) and 123 myopic patients who did not use contact lenses (control group). Intraocular pressure (IOP) was measured with an ocular response analyzer (ORA) and a Goldmann applanation tonometer. Central corneal thickness was measured with an ultrasonic pachymeter. Axial length and anterior chamber depth measurements were acquired with contact ultrasound A-scan biometry. The differences in ORA parameters between study and control group participants were analyzed. The mean corneal hysteresis in study and control groups was 10.1 ± 1.6 mm Hg (6.5-15.9 mm Hg) and 9.7 ± 1.5 mm Hg (6.3-14.2 mm Hg), respectively (P = 0.16). The mean corneal resistance factor was 10.4 ± 1.9 mm Hg (4.6-15.5 mm Hg) in the study group compared with 9.6 ± 1.9 mm Hg (5.1-15.0 mm Hg) in the control group. The difference for corneal resistance factor was statistically significant (P = 0.014). There was no significant difference in corneal-compensated IOP (P = 0.24). Mean Goldmann-correlated IOP was significantly higher in the study group than in control subjects (15.8 ± 3.2 vs. 14.7 ± 3.7 mm Hg) (P = 0.044). None of the corneal biomechanical parameters was significantly correlated to duration of contact lens usage in the study group. Our results suggest that ORA-generated parameters may be different in subjects with and without contact lens usage. Further longitudinal studies need to be performed to establish the relevance of our results.

  18. Determination of a Critical Sea Ice Thickness Threshold for the Central Arctic Ocean

    Ford, V.; Frauenfeld, O. W.; Nowotarski, C. J.

    2017-12-01

    While sea ice extent is readily measurable from satellite observations and can be used to assess the overall survivability of the Arctic sea ice pack, determining the spatial variability of sea ice thickness remains a challenge. Turbulent and conductive heat fluxes are extremely sensitive to ice thickness but are dominated by the sensible heat flux, with energy exchange expected to increase with thinner ice cover. Fluxes over open water are strongest and have the greatest influence on the atmosphere, while fluxes over thick sea ice are minimal as heat conduction from the ocean through thick ice cannot reach the atmosphere. We know that turbulent energy fluxes are strongest over open ocean, but is there a "critical thickness of ice" where fluxes are considered non-negligible? Through polar-optimized Weather Research and Forecasting model simulations, this study assesses how the wintertime Arctic surface boundary layer, via sensible heat flux exchange and surface air temperature, responds to sea ice thinning. The region immediately north of Franz Josef Land is characterized by a thickness gradient where sea ice transitions from the thickest multi-year ice to the very thin marginal ice seas. This provides an ideal location to simulate how the diminishing Arctic sea ice interacts with a warming atmosphere. Scenarios include both fixed sea surface temperature domains for idealized thickness variability, and fixed ice fields to detect changes in the ocean-ice-atmosphere energy exchange. Results indicate that a critical thickness threshold exists below 1 meter. The threshold is between 0.4-1 meters thinner than the critical thickness for melt season survival - the difference between first year and multi-year ice. Turbulent heat fluxes and surface air temperature increase as sea ice thickness transitions from perennial ice to seasonal ice. While models predict a sea ice free Arctic at the end of the warm season in future decades, sea ice will continue to transform

  19. Study on the establishment of corneal alkali chemical injury on rats

    Nan Hu

    2013-06-01

    Full Text Available AIM:To investigate the appropriate methods to establish corneal alkali chemical injury on rats. METHODS:The rats(n=87were randomly divided into three groups. Corneal alkali injury was induced by placing 1mol/L NaOH soaked filter paper on the limbus of right cornea for 20 seconds(group A, n=34or 40 seconds(group B, n=23, and on the central axis of the right cornea for 40 seconds(group C, n=30respectively. Corneal transparency, corneal ulceration, and corneal neovascularization were observed and recorded under slit- lamp biomicroscope on day 7 post-operation. RESULTS: Incidence of corneal ulceration, corneal perforation and positive rate of corneal fluorescein staining in limbal corneal injury groups(group A and Bwere significantly higher than that of central corneal injury group(group C(P<0.05. Incidence of corneal ulceration and corneal perforation in group B was significantly higher than group A(P<0.05. Corneal neovascularization was observed in all three groups. CONCLUSION: Corneal alkali burns induced by 3mm diameter central cornea injury are fit for the study of corneal neovascularization, while those induced by limbus injury for 20 seconds are fit for the study on limbal stem cells deficiency.

  20. Corneal biomechanical properties in healthy children measured by corneal visualization scheimpflug technology.

    He, Miao; Ding, Hui; He, Hong; Zhang, Chi; Liu, Liangping; Zhong, Xingwu

    2017-05-17

    The aim of this study was to evaluate corneal biomechanical properties in a population of healthy children in China using corneal visualization Scheimpflug technology (CST). All children underwent complete bi-ocular examinations. CST provided intraocular pressure (IOP) and corneal biomechanical parameters, including time, velocity, length and deformation amplitude at first applanation (A1T, A1V, A1L, A1DA), at second applanation (A2T, A2V, A2L, A2DA), highest concavity time (HCT), maximum deformation amplitude (MDA), peak distance (PD), and radius of curvature (RoC). Pearson correlation analysis was used to assess the impacts of demographic factors, central corneal thickness (CCT), spherical equivalent (SE), and IOP on corneal biomechanics. One hundred eight subjects (32 girls and 76 boys) with the mean age of 10.80 ± 4.13 years (range 4 to18 years) were included in the final analyses. The right and left eyes were highly symmetrical in SE (p = 0.082), IOP (p = 0.235), or CCT (p = 0.210). Mean A1T of the right eyes was 7.424 ± 0.340 ms; the left eyes 7.451 ± 0.365 ms. MDA was 0.993 ± 0.102 mm in the right eyes and 0.982 ± 0.100 mm in the left eyes. Mean HCT of the right eyes was 16.675 ± 0.502 ms; the left eyes 16.735 ± 0.555 ms. All CST parameters of both eye were remarkably symmetrical with the exception of A2L (p = 0.006), A1DA (p = 0.025). The majority of CST parameters of both eyes were significantly correlated with CCT and IOP (p children eyes. Several CST biomechanical parameters in children are modified by CCT and IOP.

  1. Construction of a human corneal stromal equivalent with non-transfected human corneal stromal cells and acellular porcine corneal stromata.

    Diao, Jin-Mei; Pang, Xin; Qiu, Yue; Miao, Ying; Yu, Miao-Miao; Fan, Ting-Jun

    2015-03-01

    A tissue-engineered human corneal stroma (TE-HCS) has been developed as a promising equivalent to the native corneal stroma for replacement therapy. However, there is still a crucial need to improve the current approaches to render the TE-HCS equivalent more favorable for clinical applications. At the present study, we constructed a TE-HCS by incubating non-transfected human corneal stromal (HCS) cells in an acellular porcine corneal stromata (aPCS) scaffold in 20% fetal bovine serum supplemented DMEM/F12 (1:1) medium at 37 °C with 5% CO2in vitro. After 3 days of incubation, the constructed TE-HCS had a suitable tensile strength for transplantation, and a transparency that is comparable to native cornea. The TE-HCS had a normal histological structure which contained regularly aligned collagen fibers and differentiated HCS cells with positive expression of marker and functional proteins, mimicking a native HCS. After transplantation into rabbit models, the TE-HCS reconstructed normal corneal stroma in vivo and function well in maintaining corneal clarity and thickness, indicating that the completely biological TE-HCS could be used as a HCS equivalent. The constructed TE-HCS has promising potentials in regenerative medicine and treatment of diseases caused by corneal stromal disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Corneal and Retinal Neuronal Degeneration in Early Stages of Diabetic Retinopathy.

    Srinivasan, Sangeetha; Dehghani, Cirous; Pritchard, Nicola; Edwards, Katie; Russell, Anthony W; Malik, Rayaz A; Efron, Nathan

    2017-12-01

    To examine the neuronal structural integrity of cornea and retina as markers for neuronal degeneration in nonproliferative diabetic retinopathy (NPDR). Participants were recruited from the broader Brisbane community, Queensland, Australia. Two hundred forty-one participants (187 with diabetes and 54 nondiabetic controls) were examined. Diabetic retinopathy (DR) was graded according to the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. Corneal nerve fiber length (CNFL), corneal nerve branch density (CNBD), corneal nerve fiber tortuosity (CNFT), full retinal thickness, retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), focal (FLV) and global loss volumes (GLV), hemoglobin A1c (HbA1c), nephropathy, neuropathy, and cardiovascular measures were examined. The central zone (P = 0.174), parafoveal thickness (P = 0.090), perifovea (P = 0.592), RNFL (P = 0.866), GCC (P = 0.798), and GCC GLV (P = 0.338) did not differ significantly between the groups. In comparison to the control group, those with very mild NPDR and those with mild NPDR had significantly higher focal loss in GCC volume (P = 0.036). CNFL was significantly lower in those with mild NPDR (P = 0.004) in comparison to the control group and those with no DR. The CNBD (P = 0.094) and CNFT (P = 0.458) did not differ between the groups. Both corneal and retinal neuronal degeneration may occur in early stages of diabetic retinopathy. Further studies are required to examine these potential markers for neuronal degeneration in the absence of clinical signs of DR.

  3. Comparative analysis of corneal morphological changes after transversal and torsional phacoemulsification through 2.2 mm corneal incision.

    Assaf, Ahmed; Roshdy, Maged Maher

    2013-01-01

    This paper compares and evaluates the corneal morphological changes occurring after cataract surgery through a 2.2 mm corneal incision. We use two platforms for comparison and evaluation, transversal and torsional phacoemulsification. This study includes 139 consecutive cataractous eyes (nuclear color 2-4, according to the Lens Opacities Classification System III [LOCSIII]) of 82 patients undergoing cataract surgery through a 2.2 mm corneal incision. Two different phacoemulsification platforms were used and assigned randomly: we used the WhiteStar Signature(®) system with the Ellips™ FX transversal continuous ultrasound (US) mode for group I (mean age: 65.33 ± 6.97 years), and we used the Infiniti(®) system with the OZil(®) Intelligent Phaco (IP) torsional US mode for group II (mean age: 64.02 ± 7.55 years). The corneal endothelium and pachymetry were evaluated preoperatively and at 1 month postoperatively. Incision size changes were also evaluated. All surgeries were uneventful. Before intraocular lens implantation, the mean incision size was 2.24 ± 0.06 mm in both groups (P = 0.75). In terms of corneal endothelial cell density, neither preoperative (I vs II: 2304.1 ± 122.5 cell/mm(2) vs 2315.6 ± 83.1 cell/mm(2), P = 0.80) nor postoperative (I vs II: 2264.1 ± 124.3 cell/mm(2) vs 2270.3 ± 89.9 cell/mm(2), P = 0.98) differences between the groups were statistically significant. The mean endothelial cell density loss was 1.7% ± 1.6% and 2.0% ± 1.4% in groups I and II, respectively. Furthermore, no significant differences between groups I and II were found preoperatively (P = 0.40) and postoperatively (P = 0.68) in central pachymetry. With surgery, the mean increase in central pachymetry was 28.1 ± 23.6 μm and 24.0 ± 24.0 μm in groups I and II, respectively (P = 0.1). Ellips™ FX transversal and OZil(®) IP torsional phacoemulsification modes are safe for performing cataract surgery, inducing minimal corneal thickness and endothelial changes.

  4. Comparative analysis of corneal morphological changes after transversal and torsional phacoemulsification through 2.2 mm corneal incision

    Assaf A

    2013-01-01

    Full Text Available Ahmed Assaf, Maged Maher RoshdyOphthalmology Department, Ain Shams University, Cairo, EgyptPurpose: This paper compares and evaluates the corneal morphological changes occurring after cataract surgery through a 2.2 mm corneal incision. We use two platforms for comparison and evaluation, transversal and torsional phacoemulsification.Patients and methods: This study includes 139 consecutive cataractous eyes (nuclear color 2–4, according to the Lens Opacities Classification System III [LOCSIII] of 82 patients undergoing cataract surgery through a 2.2 mm corneal incision. Two different phacoemulsification platforms were used and assigned randomly: we used the WhiteStar Signature® system with the Ellips™ FX transversal continuous ultrasound (US mode for group I (mean age: 65.33 ± 6.97 years, and we used the Infiniti® system with the OZil® Intelligent Phaco (IP torsional US mode for group II (mean age: 64.02 ± 7.55 years. The corneal endothelium and pachymetry were evaluated preoperatively and at 1 month postoperatively. Incision size changes were also evaluated.Results: All surgeries were uneventful. Before intraocular lens implantation, the mean incision size was 2.24 ± 0.06 mm in both groups (P = 0.75. In terms of corneal endothelial cell density, neither preoperative (I vs II: 2304.1 ± 122.5 cell/mm2 vs 2315.6 ± 83.1 cell/mm2, P = 0.80 nor postoperative (I vs II: 2264.1 ± 124.3 cell/mm2 vs 2270.3 ± 89.9 cell/mm2, P = 0.98 differences between the groups were statistically significant. The mean endothelial cell density loss was 1.7% ± 1.6% and 2.0% ± 1.4% in groups I and II, respectively. Furthermore, no significant differences between groups I and II were found preoperatively (P = 0.40 and postoperatively (P = 0.68 in central pachymetry. With surgery, the mean increase in central pachymetry was 28.1 ± 23.6 µm and 24.0 ± 24.0 µm in groups I and II, respectively (P = 0.1.Conclusion: Ellips™ FX transversal and OZil® IP torsional

  5. Fiabilidad de la Tomografía de coherencia óptica de dominio espectral para la medición del espesor Corneal Central

    Correa Pérez, María Encarnación

    2013-01-01

    La paquimetría es la medida del grosor corneal en cualquiera de sus localizaciones. Resulta indispensable en la evaluación y monitorización de algunas enfermedades oculares. El Paquimétro Ultrasónico de contacto se considerada “gold standard”. En los últimos años, la paquimetría se ha incluido en equipos diagnósticos complejos no específicamente diseñados para ello, sin precisar contacto corneal. Ejemplo de ésto son los sistemas de Tomografía de Coherencia Óptica (OCT) de Dominio Espectral...

  6. Corneal melanosis successfully treated using topical mitomycin-C and alcohol corneal epitheliectomy: a 3-year follow-up case report

    Mehmet Balcı

    2015-08-01

    Full Text Available ABSTRACTWe report a case of primary acquired corneal melanosis without atypia associated with corneal haze in a patient with a history of limbal malignant melanoma and the effect of mitomycin-C. A 75-year-old woman with a history of limbal malignant melanoma presented with loss of vision in right eye. Corneal examination showed a patchy melanotic pigmentation with a central haze. Topical mitomycin-C improved visual acuity and corneal haze. However, the pigmented lesions persisted, and they were removed with alcohol corneal epitheliectomy. Histopathological examination demonstrated primary acquired melanosis without atypia. The lesions were successfully removed, and there were no recurrences during the follow-up period of 36 months. The association of conjunctival and corneal melanosis without atypia is a rare condition. In addition, co-existence of central corneal haze and melanosis may decrease visual acuity. Topical mitomycin-C and alcohol corneal epitheliectomy can be useful treatments in this condition.

  7. Application of Corvis ST to evaluate the effect of femtosecond laser-assisted cataract surgery on corneal biomechanics.

    Wei, Yinjuan; Xu, Lingxiao; Song, Hui

    2017-08-01

    The aim of the present study was to evaluate the effects of femtosecond laser-assisted cataract surgery (FLACS) and phacoemulsification on corneal biomechanics using corneal visualization Scheimpflug technology. The medical records of 50 eyes from 50 patients who received phacoemulsification and intraocular lens implantation because of age-related factors between June 2014 and September 2014 were retrospectively analyzed. FLACS was used in 12 eyes (FLACS group), and conventional phacoemulsification in 38 eyes (PHACO group). The evaluation of corneal biomechanical parameters included the first/second applanation time (A-time1/A-time2), the first/second applanation length (A-length1/A-length2), corneal velocity during the first/second applanation moment (Vin/Vout), highest concavity time, highest concavity-radius (HC-radius), peak distance (PD), deformation amplitude (DA), central corneal thickness (CCT), and intraocular pressure (IOP). The differences in A-length1/A-length2, IOP, CCT, PD, and DA were significant in the PHACO group between those before, 1 week after, and 1 month after surgery. No significant differences in corneal biomechanical parameters were found between those at 1 month after surgery and before surgery. There were significant differences in IOP and CCT in the FLACS group between those before, 1 week after, and 1 month after surgery. There were no significant differences in the other corneal biomechanical parameters. No significant differences were found in corneal biomechanical parameters between those 1 month after surgery and before surgery. There were significant differences in A-length1/A-length2, CCT, PD, and DA between the two groups at 1 week after surgery. There were no significant differences in corneal biomechanical parameters between the two groups at 1 month after surgery. In conclusion, the effect of FLACS on corneal biomechanics is smaller than that of phacoemulsification. The corneal biomechanical parameters are restored to

  8. Corneal endothelium in xeroderma pigmentosum: clinical specular microscopy study.

    Mohamed, Ashik; Peguda, Rajini; Ramappa, Muralidhar; Ali, Mohammad Javed; Chaurasia, Sunita

    2016-06-01

    Xeroderma pigmentosum is a condition caused due to a defective DNA repair mechanism when exposed to ultraviolet radiation. Many of the patients with this disorder develop severely oedematous cornea with varying degrees of anterior corneal haze, which necessitates a full-thickness keratoplasty or selective endothelial keratoplasty. Presence of corneal oedema suggests that these patients have a dysfunctional endothelium. The purpose of this study is to evaluate the corneal endothelium in the patients with xeroderma pigmentosum when clinical specular microscopy was feasible. Thirteen patients with classic skin changes of xeroderma pigmentosum were included in the study conducted during January 2010-December 2012. An age-matched group of 13 volunteers were included as controls who were emmetropes without any history of ocular or systemic illness. Corneal endothelium was assessed using specular microscopy from the central clear area of cornea. The mean age of the patients with xeroderma pigmentosum was 16.6±7.2 years and that of the controls was 17.4±6.9 years (p=0.78). The number of analysed cells and endothelial cell density were significantly higher in controls (pxeroderma pigmentosum (p≤0.007). The specular microscopic findings in patients with xeroderma pigmentosum are suggestive of an accelerated endothelial cell loss. It is pertinent that the treating physicians must be involved in emphasising proper ocular protection from ultraviolet radiation to prevent avoidable blindness from xeroderma pigmentosum. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  9. Reproducibility of corneal, macular and retinal nerve fiber layer ...

    side the limits of a consulting room.5. Reproducibility of ... examination, intraocular pressure and corneal thickness ... All OCT measurements were taken between 2 and 5 pm ..... CAS-OCT, Slit-lamp OCT, RTVue-100) have shown ICC.

  10. Research on mouse model of grade II corneal alkali burn

    Jun-Qiang Bai

    2016-04-01

    Full Text Available AIM: To choose appropriate concentration of sodium hydroxide (NaOH solution to establish a stable and consistent corneal alkali burn mouse model in grade II. METHODS: The mice (n=60 were randomly divided into four groups and 15 mice each group. Corneal alkali burns were induced by placing circle filter paper soaked with NaOH solutions on the right central cornea for 30s. The concentrations of NaOH solutions of groups A, B, C, and D were 0.1 mol/L, 0.15 mol/L , 0.2 mol/L, and 1.0 mol/L respectively. Then these corneas were irrigated with 20 mL physiological saline (0.9% NaCl. On day 7 postburn, slit lamp microscope was used to observe corneal opacity, corneal epithelial sodium fluorescein staining positive rate, incidence of corneal ulcer and corneal neovascularization, meanwhile pictures of the anterior eyes were taken. Cirrus spectral domain optical coherence tomography was used to scan cornea to observe corneal epithelial defect and corneal ulcer. RESULTS: Corneal opacity scores ( were not significantly different between the group A and group B (P=0.097. Incidence of corneal ulcer in group B was significantly higher than that in group A (P=0.035. Incidence of corneal ulcer and perforation rate in group B was lower than that in group C. Group C and D had corneal neovascularization, and incidence of corneal neovascularization in group D was significantly higher than that in group C (P=0.000. CONCLUSION: Using 0.15 mol/L NaOH can establish grade II mouse model of corneal alkali burns.

  11. Goldmann applanation tonometry compared with corneal-compensated intraocular pressure in the evaluation of primary open-angle Glaucoma

    Ehrlich Joshua R

    2012-09-01

    Full Text Available Abstract Background To better understand the role of corneal properties and intraocular pressure (IOP in the evaluation of primary open-angle glaucoma (POAG; and to determine the feasibility of identifying glaucomatous optic neuropathy (GON using IOP corrected and uncorrected for corneal biomechanics. Methods Records from 1,875 eyes of consecutively evaluated new patients were reviewed. Eyes were excluded if central corneal thickness (CCT or Ocular Response Analyzer (ORA measurements were unavailable. Presence or absence of GON was determined based on morphology of the optic disc, rim and retinal nerve fiber layer at the time of clinical examination, fundus photography and Heidelberg Retinal Tomography. Goldmann-applanation tonometry (GAT in the untreated state was recorded and Goldmann-correlated (IOPg and corneal-compensated IOP (IOPcc were obtained using the ORA. Glaucomatous eyes were classified as normal or high-tension (NTG, HTG using the conventional cutoff of 21 mm Hg. One eligible eye was randomly selected from each patient for inclusion. Results A total of 357 normal, 155 HTG and 102 NTG eyes were included. Among NTG eyes, IOPcc was greater than GAT (19.8 and 14.4 mm Hg; p  Conclusions IOPcc may account for measurement error induced by corneal biomechanics. Compared to GAT, IOPcc may be a superior test in the evaluation of glaucoma but is unlikely to represent an effective diagnostic test.

  12. Polysaccharide coating of human corneal endothelium

    Schroder, H D; Sperling, S

    1977-01-01

    Electron microscopy revealed the presence of a 600-1500 A thick layer of polysaccharide on the surface of human corneal endothelial cells. The surface layer was visualized by combined fixation and staining in a mixture of ruthenium red and osmium tetroxide. The coating material was stable for at ...... for at least 39 h post mortem and was retained on disintegrating cells....

  13. Reproducibility of flap thickness with IntraLase FS and Moria LSK-1 and M2 microkeratomes.

    Talamo, Jonathan H; Meltzer, Jeremy; Gardner, John

    2006-06-01

    To compare flap thickness reproducibility of the femtosecond laser and two mechanical microkeratomes. Flap thickness for all eyes was measured as the difference between the preoperative (day of surgery) full corneal thickness and post-flap creation central stromal bed thickness using ultrasonic pachymetry. Flap thickness values produced by three different microkeratome systems were compared for accuracy and reproducibility. For 99 flaps created using the IntraLase FS laser with an intended thickness of 110 microm, the mean achieved thickness was 119 +/- 12 microm (range: 82 to 149 microm). In 100 eyes treated with the Moria LSK-1 microkeratome with an intended flap thickness of 160 microm, the mean achieved thickness was 130 +/- 19 microm (range: 71 to 186 microm). In 135 eyes treated with the Moria M2 microkeratome with an intended flap thickness of 130 microm, mean thickness was 142 +/- 24 microm (range: 84 to 203 microm). The standard deviation and range of corneal flap thickness created with the IntraLase FS laser was significantly smaller than either mechanical microkeratome (P < .0001). When compared to two commonly used mechanical microkeratomes, mean achieved flap thickness was more reproducible with the IntraLase FS laser, reducing the comparative risk of overly thick flaps.

  14. Tear Mediators in Corneal Ectatic Disorders.

    Dorottya Pásztor

    Full Text Available To compare the concentrations of 11 tear mediators in order to reveal the biochemical difference between pellucid marginal degeneration (PMD and keratoconus (KC.We have designed a cross-sectional study in which patients with corneal ectasia based on slit-lamp biomicroscopy and Pentacam HR (keratometry values (K1, K2, Kmax, astigmatism, minimal radius of curvature (Rmin, corneal thickness (Apex and Min, indices (surface variation, vertical asymmetry, keratoconus, central keratoconus, height asymmetry and decentration were enrolled. Eyes of keratoconic patients were similar to the PMD patients in age and severity (K2, Kmax and Rmin. Non-stimulated tear samples were collected from nine eyes of seven PMD patients, 55 eyes of 55 KC patients and 24 eyes of 24 healthy controls. The mediators' (interleukin -6, -10, chemokine ligand 5, -8, -10, matrix metalloproteinase (MMP -9, -13, tissue inhibitor of metalloproteinases (TIMP-1, tissue plasminogen activator, plasminogen activator inhibitor, nerve growth factor concentrations were measured using Cytometric Bead Array.MMP-9 was the only mediator which presented relevant variances between the two patient groups (p = 0.005. The ratios of MMP-9 and TIMP-1 were 2.45, 0.40 and 0.23 in PMD, KC and the controls, respectively.As far as we are aware, this is the first study that aims to reveal the biochemical differences between PMD and KC. Further studies of biomarkers to investigate the precise role of these mediators need to be defined, and it is important to confirm the observed changes in a larger study to gain further insights into the molecular alterations in PMD.

  15. Case Report: Corneal Pyogenic Granuloma: Rare Complication of ...

    Slit lamp examination showed vascularized central corneal mass with surrounding stromal infiltrates. The mass was excised, and histopathological examination confirmed pyogenic granuloma of the cornea. Conclusion: Corneal pyogenic granuloma could be a rare complication of infectious keratitis. Therefore, it should be ...

  16. Deepening Fornix Technique Using Central Split-Medium Thickness Skin Graft to Treat Contracted Anophthalmic Sockets.

    AlHassan, Sultan; Galindo-Ferreiro, Alicia; Khandekar, Rajiv; AlShaikh, Osama; Schellini, Silvana Artioli

    2018-05-08

    The aim of thhis study was to present the outcomes of postauricular split-medium thickness skin graft (SMTSG) to treat anophthalmic sockets with contracted fornices. This case series enrolled patients with grade 2 or 3 anophthalmic sockets between 2015 and 2016. Data were collected on patient demographics, objective and subjective parameters preoperatively and 180 days postoperatively. Success of the surgery was graded on the height of the graft, the depth of the superior and inferior fornices, and presence/abscence of lagophthalmos, entropion, and ability to retain an external prosthesis. Eighteen patients were enrolled with a mean age of 35.9 ± 18 years. The median height of the graft was 22 mm (25% quartile = 18.75) when removed and 20 mm (25% quartile = 16) postoperatively. The median depth of the superior fornix was 6.5 mm (25% quartile = 4.5 mm) preoperatively and 10 mm (25% quartile = 8 mm) postoperatively (P = 0.5). The median inferior fornix depth was 7 mm (25% quartile = 3.5 mm) preoperatively and 8 mm (25% quartile = 5 mm) (P = 0.27) postoperatively. Preoperatively, there were 13 (72.2%) patients with lagophthalmos, 10 (44.4%) with entropion, 3 (37.5%) with poor prosthesis retention, and 5 (62.5%) who were unable to retain the prosthesis. Postoperatively, 7 (38.9%) patients had lagophthamos, 1 (5.6%) had entropion, and all the patients could retain the prosthesis. None of the sockets had a foul odor postoperatively. Postauricular SMTSG achieves successful outcomes for the treatment of contracted anophthalmic sockets, reshaping the anterior socket surface and deepening the fornices.

  17. Glaucoma after corneal replacement.

    Baltaziak, Monika; Chew, Hall F; Podbielski, Dominik W; Ahmed, Iqbal Ike K

    Glaucoma is a well-known complication after corneal transplantation surgery. Traditional corneal transplantation surgery, specifically penetrating keratoplasty, has been slowly replaced by the advent of new corneal transplantation procedures: primarily lamellar keratoplasties. There has also been an emergence of keratoprosthesis implants for eyes that are high risk of failure with penetrating keratoplasty. Consequently, there are different rates of glaucoma, pathogenesis, and potential treatment in the form of medical, laser, or surgical therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Comparación de la medición del grosor corneal central medido con el paquímetro incluido en el Wavelight® Ex500 Excimer Laser y el tomógrafo de cámara de Scheimpflug Pentacam® en sujetos sanos

    Manuel Garza León

    2017-01-01

    Conclusiones: Nuestros resultados demuestran que el paquímetro incluido en el Wavelight® Ex500 Excimer Laser es una buena alternativa para la medición del grosor corneal central al Pentacam® en pacientes sanos.

  19. Association of CHRDL1 mutations and variants with X-linked megalocornea, Neuhäuser syndrome and central corneal thickness

    Davidson, Alice E; Cheong, Sek-Shir; Hysi, Pirro G

    2014-01-01

    We describe novel CHRDL1 mutations in ten families with X-linked megalocornea (MGC1). Our mutation-positive cohort enabled us to establish ultrasonography as a reliable clinical diagnostic tool to distinguish between MGC1 and primary congenital glaucoma (PCG). Megalocornea is also a feature of Ne...

  20. Corneal endothelial cell density and morphology in patients with acromegaly.

    Hatipoglu, Esra; Arici, Ceyhun; Arslan, Osman Sevki; Dikkaya, Funda; Sultan, Pinar; Kadioglu, Pinar; Gundogdu, Sadi

    2014-12-01

    Acromegaly has various impacts on many organs. The ophthalmologic effects of acromegaly have not yet been investigated in detail. The aim of the current study was to evaluate qualitative and quantitative changes in corneal endothelial cells and central corneal thickness (CCT) of the patients with acromegaly. In this prospective, cross-sectional study, 128 eyes of 64 patients with acromegaly (female/male=40/24) and 208 eyes of 104 age and gender-matched healthy volunteers (female/male=69/35) were included. Endothelial cell density (ECD), cellular area (CA), coefficient of variation (CV) in cell size, percentage of hexagonal cells, and CCT were measured in patients with acromegaly and in healthy volunteers using the noncontact specular microscopy (SP-3000P: Topcon Corporation, Tokyo, Japan). ECD and CA were lower in cases with acromegaly than in controls (ECD in acromegaly: 2615.65 cell/mm(2) and in controls: 2700.35 cell/mm(2); p=0.002. CA in acromegaly: 382.30μm(2) and in controls: 400.30μm(2); p=0.02). In the entire group with acromegaly, the time elapsed since diagnosis was positively correlated with CA and was negatively correlated with ECD (r=+0.39, p=0.001 and r=-0.42, p=0.001). The endothelial layer of the cornea may be under risk of impairment with prolonged disease duration in acromegaly. Consistency of the corneal endothelium should be also sought during long-term follow-up of the cases with acromegaly. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Inverse cutting of posterior lamellar corneal grafts by a femtosecond laser.

    Hjortdal, Jesper; Nielsen, Esben; Vestergaard, Anders; Søndergaard, Anders

    2012-01-01

    Posterior lamellar grafting of the cornea has become the preferred technique for treatment of corneal endothelial dysfunction. Posterior lamellar grafts are usually cut by a micro-keratome or a femto-second laser after the epithelial side of the donor cornea has been applanated. This approach often results in variable central graft thickness in different grafts and an increase in graft thickness towards the periphery in every graft. The purpose of this study was to evaluate if posterior lamellar grafts can be prepared from the endothelial side by a femto-second laser, resulting in reproducible, thin grafts of even thickness. A CZM 500 kHz Visumax femto-second laser was used. Organ cultured donor grafts were mounted in an artifical anterior chamber with the endothelial side up and out. Posterior grafts of 7.8 mm diameter and 130 micron thickness were prepared by femto-second laser cutting. A standard DSAEK procedure was performed in 10 patients with Fuchs endothelial dystrophy. Patients were followed-up regularly and evaluated by measurement of complications, visual acuity, corneal thickness (Pentacam HR), and endothelial cell density. Femto-laser cutting of grafts and surgery was uncomplicated. Rebubbling was necessary in 5 of 10 cases (normally only in 1 of 20 cases). All grafts were attached and cleared up during the first few weeks. After six months, the average visual acuity was 0.30 (range: 0.16 to 0.50), corneal thickness was 0.58 mm (range 0.51 to 0.63), and endothelial cell density was 1.570 per sq. mm (range: 1.400 to 2.000 cells per sq. mm). The grafts were of uniform thickness, but substantial interface haze was present in most grafts. Posterior lamellar corneal grafts can be prepared from the endothelial side using a femto-second laser. All grafts were clear after 6 months with satisfying endothelial cell counts. Poor visual acuity caused by interface scatter was observed in most patients. Femto-second laser cutting parameters needs to be optimised to

  2. Evaluation of corneal symmetry after UV corneal crosslinking for keratoconus

    Mofty H

    2017-11-01

    Full Text Available Hanan Mofty,1,2 Khaled Alzahrani,2 Fiona Carley,3 Sophie Harper,3 Arun Brahma,3 Leon Au,3 Debbie Morley,3 M Chantal Hillarby2 1Optometry Department, College of Applied Medical Science, King Saud University, Riyadh, Kingdom of Saudi Arabia; 2Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, 3Manchester Royal Eye Hospital, Manchester, UK Purpose: The purpose of this study was to assess UV corneal crosslinking (CXL treatment outcomes for keratoconus by evaluating the corneal regularity in patients through follow-up using the Oculus Pentacam.Patients and methods: A total of 18 eyes from CXL patients with keratoconus were studied before and after CXL treatment, and six eyes from six patients who were not treated with CXL served as controls. Treated patients had Pentacam images taken before CXL treatment and regularly 3 months post treatment up to the 12th month. Controls were imaged during their first appointment and after 12 months. Symmetry and asphericity were evaluated and correlated with both best-corrected visual acuity (BCVA and maximum K-readings.Results: In the CXL-treated group, there was a significant improvement in the index of symmetrical variation (ISV and keratoconus index (KI at 3 months and in the index of height asymmetry (IHA and minimum radius of curvature (Rmin at 9 months post treatment. On the contrary, the untreated group’s indices showed some significant worsening in ISV, KI, central keratoconus index (CKI, and Rmin. A novel finding in our study was a slight positive shift of anterior asphericity in the 6 mm, 7 mm, and 8 mm 3 months after treatment, which had a correlation with BCVA (R2=0.390, p=0.053 and a strong correlation with maximum K-reading (R2=0.690, p=0.005. However, the untreated group had no significant changes after 1 year.Conclusion: The corneal asymmetrical shape is associated with the spherical aberration alteration

  3. Optical Coherence Tomography Examination of the Anterior Segment in a Case of Corneal Perforation and Lens Trauma by Chestnut Burr

    Takashi Ono

    2018-02-01

    Full Text Available Chestnut burrs, the thorny encapsulation of chestnut fruit, can sometimes cause corneal injuries and ulceration, with poor prognoses. We report a case of corneal perforation and damaged anterior lens capsule due to a chestnut burr, using anterior segment optical coherence tomography (AS-OCT. A 67-year-old woman with a chestnut burr injury in her right eye was referred to our hospital. Her right best-corrected visual acuity (BCVA was 0.8. Slit-lamp examination and AS-OCT showed perforation involving the endothelial layer at the center of the cornea. The iris and anterior lens capsule were damaged. Cell infiltration was observed around the wound. Bacterial examination showed gram-positive cocci but no fungi. The patient was diagnosed with a corneal perforation and bacterial keratitis. Levofloxacin 1.5% and cefmenoxime treatments were initiated and a soft contact lens was placed to seal the wound. On day 3, there was no improvement in the corneal cell infiltration, but AS-OCT suggested that the inner wound had closed. A culture test revealed the presence of Propionibacterium acnes, which was sensitive to both levofloxacin and cefmenoxime. Therefore, we continued the same antibiotic treatment. On day 26, the opacification and cell infiltration at the center of the cornea had improved. AS-OCT showed healing of the corneal wound with reduction in the central corneal thickness. Her BCVA improved to 1.0. AS-OCT was a valuable tool to noninvasively observe wound shape and detect the presence of any intracorneal foreign bodies.

  4. Human corneal epithelial subpopulations

    Søndergaard, Chris Bath

    2013-01-01

    Corneal epithelium is being regenerated throughout life by limbal epithelial stem cells (LESCs) believed to be located in histologically defined stem cell niches in corneal limbus. Defective or dysfunctional LESCs result in limbal stem cell deficiency (LSCD) causing pain and decreased visual acuity...... subpopulations in human corneal epithelium using a combination of laser capture microdissection and RNA sequencing for global transcriptomic profiling. We compared dissociation cultures, using either expansion on γ-irradiated NIH/3T3 feeder cells in serum-rich medium or expansion directly on plastic in serum...

  5. Corneal topography with an aberrometry-topography system.

    Mülhaupt, Michael; Dietzko, Sven; Wolffsohn, James; Bandlitz, Stefan

    2018-05-07

    To investigate the agreement between the central corneal radii and corneal eccentricity measurements generated by the new Wave Analyzer 700 Medica (WAV) compared to the Keratograph 4 (KER) and to test the repeatability of the instruments. 20 subjects (10 male, mean age 29.1 years, range 21-50 years) were recruited from the students and staff of the Cologne School of Optometry. Central corneal radii for the flat (r c/fl ) and steep (r c/st ) meridian as well as corneal eccentricity for the nasal (e nas ), temporal (e temp ), inferior (e inf ) and superior (e sup ) directions were measured using WAV and KER by one examiner in a randomized order. Central radii of the flat (r c/fl ) and steep (r c/st ) meridian measured with both instruments were statically significantly correlated (r = 0.945 and r = 0.951; p  0.05). Limits of agreement (LoA) indicate a better repeatability for the KER compared to WAV. Corneal topography measurements captured with the WAV were strongly correlated with the KER. However, due to the differences in measured corneal radii and eccentricities, the devices cannot be used interchangeably. For corneal topography the KER demonstrated better repeatability. Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  6. Riboflavin for corneal cross-linking.

    O'Brart, D P S

    2016-06-01

    Corneal collagen cross-linking (CXL) with riboflavin and ultraviolet A (UVA) radiation is the first therapeutic modality that appears to arrest the progression of keratoconus and other corneal ectasias. Riboflavin is central to the process, acting as a photosensitizer for the production of oxygen singlets and riboflavin triplets. These free radicals drive the CXL process within the proteins of the corneal stroma, altering its biomechanical properties. Riboflavin also absorbs the majority of the UVA radiation, which is potentially cytotoxic and mutagenic, within the anterior stroma, preventing damage to internal ocular structures, such as the corneal endothelium, lens and retina. Clinical studies report cessation of ectatic progression in over 90% of cases and the majority document significant improvements in visual, keratometric and topographic parameters. Clinical follow-up is limited to 5-10 years, but suggests sustained stability and enhancement in corneal shape. Sight-threatening complications are rare. The optimal stromal riboflavin dosage for CXL is as yet undetermined. Copyright 2016 Prous Science, S.A.U. or its licensors. All rights reserved.

  7. Corneal swelling caused by conventional and new-design low-Dk soft contact lenses following a 10-day daily wear trial regime.

    Rho, Chang Rae; Pandey, Chitra; Kim, Su Young; Kim, Man Soo

    2014-02-01

    To investigate the efficacy and safety of a fenestrated and channelled soft contact lens (F-SCL) compared to a standard and non-fenestrated soft contact lens (S-SCL) in experienced soft contact lens (SCL) wearers. This was a randomised, crossover, single-blinded (subject), and multicentre clinical trial. Sixteen experienced SCL wearers were randomly divided into two groups (FS and SF). The FS group first wore F-SCLs followed by S-SCLs, each for 10 days, separated by a 1-week washout period, whereas the SF group wore the S-SCLs first and crossed over to F-SCLs in the same manner. The F-SCLs were designed with three equally spaced, symmetrical fenestrations and a partial-thickness, connecting, circumferential channel on the back surface of the mid-periphery of the lens. Measurement of central corneal thickness using ultrasonic pachymetry was performed on the day of screening, after the 1-week washout period, and after 10 days of wearing each kind of lens, based on which central corneal swelling was calculated and compared. One eye in each subject was chosen at random for analysis. Central corneal swelling was 1.92±1.73% vs. 5.26±2.14% in F-SCLs vs. S-SCLs wearers, which was statistically significant (P<0.001). There was no significant difference between the groups in terms of SCL-corrected visual acuity or SCL-related adverse events. The use of F-SCLs led to reduced corneal swelling compared to S-SCLs. The newly incorporated features appear to improve tear mixing and thereby the oxygen supply to the cornea, which results in reduced corneal oedema. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  8. Comparison of corneal biomechanics in Sjögren's syndrome and non-Sjögren's syndrome dry eyes by Scheimpflug based device.

    Long, Qin; Wang, Jing-Yi; Xu, Dong; Li, Ying

    2017-01-01

    To compare the corneal biomechanics of Sjögren's syndrome (SS) and non-SS dry eyes with Corneal Visualization Scheimpflug Technology (CorVis ST). Corneal biomechanics and tear film parameters, namely the Schirmer I test value, tear film break-up time (TBUT) and corneal staining score (CSS) were detected in 34 eyes of 34 dry eye patients with SS (SSDE group) and 34 dry eye subjects without SS (NSSDE group) using CorVis ST. The differences of the above parameters between the two groups were examined, and the relationship between corneal biomechanics and tear film parameters were observed. The differences in age, sex, intraocular pressure (IOP) and central corneal thickness (CCT) were not significant between the two groups ( P >0.05). The tear film parameters had significant differences between the SSDE group and NSSDE group (all P <0.05). Patients in the SSDE group had significantly lower A1-time and HC-time, but higher DA ( P =0.01, 0.02, and 0.02, respectively) compared with the NSSDE group. In the SSDE group, DA was negatively correlated with TBUT ( rho =-0.38, P =0.03); HC-time was negatively correlated with CSS ( rho =-0.43, P =0.02). In the NSSDE group, HC-time was again negatively correlated with CSS ( rho =-0.39, P =0.02). There are differences in corneal biomechanical properties between SSDE and NSSDE. The cornea of SSDE tends to show less "stiffness", as seen by a significantly shorter A1-time and HC-time, but larger DA, compared with the cornea of NSSDE. Biomechanical parameters can be influenced by different tear film parameters in both groups.

  9. Corneal regeneration by induced human buccal mucosa cultivated on an amniotic membrane following alkaline injury.

    Man, Rohaina Che; Yong, Then Kong; Hwei, Ng Min; Halim, Wan Haslina Wan Abdul; Zahidin, Aida Zairani Mohd; Ramli, Roszalina; Saim, Aminuddin Bin; Idrus, Ruszymah Binti Hj

    2017-01-01

    Various clinical disorders and injuries, such as chemical, thermal, or mechanical injuries, may lead to corneal loss that results in blindness. PURPOSE : The aims of this study were to differentiate human buccal mucosa (BMuc) into corneal epithelial-like cells, to fabricate engineered corneal tissue using buccal mucosal epithelial cells, and to reconstruct a damaged corneal epithelium in a nude rat model. BMuc were subjected to 10 d of induction factors to investigate the potential of cells to differentiate into corneal lineages. Corneal stem cell markers β1-integrin, C/EBPδ, ABCG2, p63, and CK3 were upregulated in the gene expression analysis in induced BMuc, whereas CK3 and p63 showed significant protein expression in induced BMuc compared to the uninduced cells. BMuc were then left to reach 80% confluency after differential trypsinization. The cells were harvested and cultivated on a commercially available untreated air-dried amniotic membrane (AM) in a Transwell system in induction medium. The corneal constructs were fabricated and then implanted into damaged rat corneas for up to 8 weeks. A significant improvement was detected in the treatment group at 8 weeks post-implantation, as revealed by slit lamp biomicroscopy analysis. The structure and thickness of the corneal layer were also analyzed using histological staining and time-domain optical coherence tomography scans and were found to resemble a native corneal layer. The protein expression for CK3 and p63 were continuously detected throughout the corneal epithelial layer in the corneal construct. In conclusion, human BMuc can be induced to express a corneal epithelial-like phenotype. The addition of BMuc improves corneal clarity, prevents vascularization, increases corneal thickness and stromal alignment, and appears to have no adverse effect on the host after implantation.

  10. Trifluoperazine: corneal endothelial phototoxicity

    Hull, D.S.; Csukas, S.; Green, K.

    1983-01-01

    Trifluoperazine is used for the treatment of psychiatric disorders. Perfusion of corneal endothelial cells with trifluoperazine-HC1 concurrent with exposure to long wavelength ultraviolet light resulted in a corneal swelling rate greater than that found in perfused corneas not exposed to ultraviolet light. Exposure of endothelial cells to 25 W incandescent light during perfusion with trifluoperazine-HC1 did not result in a higher corneal swelling rate compared to those perfused in the dark. The increased corneal swelling rate could be produced by pre-exposure of the trifluoperazine-HC1 perfusing solution to ultraviolet light suggesting the production of toxic photoproducts during exposure of trifluoperazine-HC1 to ultraviolet light. Perfusion of corneal endothelial cells with non-ultraviolet illuminated trifluoperazine-HC1 had no effect on endothelial cell membranes or ultrastructure. This is in contrast to cells perfused with trifluoperazine-HC1 that had been exposed to ultraviolet light in which there was an alteration of mitochondria and a loss of cytoplasmic homogeneity. The data imply that the trifluoperazine-HC1 photoproduct had an adverse effect on cellular transport mechanisms. The study also further demonstrates the value of the corneal endothelial cell model for identifying the physiological and anatomical changes occuring in photo-induced toxic reactions. (author)

  11. Impact of Baseline Central Retinal Thickness on Outcomes in the VIVID-DME and VISTA-DME Studies

    Edoardo Midena

    2018-01-01

    Full Text Available Purpose. To report the impact of baseline central retinal thickness (CRT on outcomes in patients with diabetic macular edema (DME in VIVID-DME and VISTA-DME. Methods. Post hoc analyses of two randomized controlled trials in which 862 DME patients were randomized 1 : 1 : 1 to treatment with intravitreal aflibercept 2.0 mg every 4 weeks (2q4, intravitreal aflibercept 2.0 mg every 8 weeks after five initial monthly doses (2q8, or macular laser photocoagulation at baseline and as needed. We compared visual and anatomical outcomes in subgroups of patients with baseline CRT < 400 μm and ≥400 μm. Results. At weeks 52 and 100, outcomes with intravitreal aflibercept 2q4 and 2q8 were superior to those in laser control-treated patients regardless of baseline CRT. When looked at in a binary fashion, the treatment effect of intravitreal aflibercept versus laser was not significantly better in the ≥400 μm than the <400 μm group; when looked at as a continuous variable, baseline CRT seemed to have an impact on the treatment effect of intravitreal aflibercept versus laser. Conclusions. Post hoc analyses of VIVID-DME and VISTA-DME demonstrated the benefits of intravitreal aflibercept treatment in DME patients with baseline CRT < 400 μm and ≥400 μm. This trial is registered with NCT01331681 and NCT01363440.

  12. Formation and preservation of greigite (Fe3S4) in a thick sediment layer from the central South Yellow Sea

    Liu, Jianxing; Mei, Xi; Shi, Xuefa; Liu, Qingsong; Liu, Yanguang; Ge, Shulan

    2018-04-01

    Sediments from continental shelves are sensitive to changes in both oceanic and terrestrial conditions, and, therefore, magnetic minerals in such sediments are affected strongly by depositional and diagenetic processes. Here, we investigated systematically an N-S transect of three sediment cores from the central South Yellow Sea (SYS) muddy area. Magnetic data indicate the presence of a horizontally distributed thick greigite-bearing layer. From an age model based on published magnetostratigraphy, accelerator mass spectrometry 14C dating ages, sedimentary characteristics and foraminiferal analysis, this layer was deposited within marine isotope stages (MIS) 17-13, following an enhanced sulphidic period over MIS 21-19 when the YS Warm Current and the associated YS Cold Water Mass were strong and where underlying sediments have higher total organic carbon, total sulphur and trace element molybdenum contents. Trace element cadmium enrichment in the greigite-bearing layers is documented for the first time, which indicates that weakly sulphidic (i.e. with trace levels of free H2S) conditions existed before greigite formed in a sulphidic environment during early diagenesis. It also indicates that subsequent conditions free of oxygen and H2S after greigite formation are more favourable for its preservation. We propose that organic matter supply was controlled over an extended period by moderate primary productivity. The combined effects of palaeoclimate and local tectonic subsidence were crucial for the formation and preservation of the identified greigite. In brief, our study improves understanding of the formation and preservation mechanisms of greigite in continental shelf sediments and reveals mid-Pleistocene palaeoenvironmental changes in the SYS.

  13. [Clinical pilot study to evaluate the efficacy of a preservative-free hypertonic ophthalmic solution for patients with symptomatic corneal edema].

    Rouland, J-F

    2015-11-01

    This exploratory clinical trial aims to assess the effect on visual acuity and central corneal thickness of an unpreserved hypertonic ophthalmic solution containing sodium chloride (5%) and sodium hyaluronate, in patients with chronic corneal edema caused by endothelial disease reducing their visual acuity. Twenty patients were enrolled and treated with the hypertonic solution (1 to 2 drops per eye, 4 times a day over 28 days). Progression of visual acuity (ETDRS score) and corneal thickness (ultrasonic pachymetry) was measured from baseline (without treatment) through the treatment period (Day 7 and Day 28). The analyses were performed on 18 patients (Full Analysis Set [FAS] population). The causes of corneal edema were Fuchs endothelial dystrophy in 10 cases and post-cataract surgery endothelial decompensation in 8 patients. The mean visual acuity values for the FAS population compared between baseline (Day-7) and one week of treatment (Day+7) show a significant 5-point VA improvement (Psolution containing sodium chloride and sodium hyaluronate significantly improved ETDRS visual acuity after one week of use. In this clinical trial, the solution also showed excellent tolerability results. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  14. Corneal tissue welding with infrared laser irradiation after clear corneal incision.

    Rasier, Rfat; Ozeren, Mediha; Artunay, Ozgür; Bahçecioğlu, Halil; Seçkin, Ismail; Kalaycoğlu, Hamit; Kurt, Adnan; Sennaroğlu, Alphan; Gülsoy, Murat

    2010-09-01

    The aim of this study was to investigate the potential of infrared lasers for corneal welding to seal corneal cuts done in an experimental animal model. Full-thickness corneal cuts on freshly enucleated bovine eyes were irradiated with infrared (809-nm diode, 980-nm diode, 1070-nm YLF, and 1980-nm Tm:YAP) lasers to get immediate laser welding. An 809-nm laser was used with the topical application of indocyanine green to enhance the photothermal interaction at the weld site. In total, 60 bovine eyes were used in this study; 40 eyes were used in the first part of the study for the determination of optimal welding parameters (15 eyes were excluded because of macroscopic carbonization, opacification, or corneal shrinkage; 2 eyes were used for control), and 20 eyes were used for further investigation of more promising lasers (YLF and Tm:YAP). Laser wavelength, irradiating power, exposure time, and spot size were the dose parameters, and optimal dose for immediate closure with minimal thermal damage was estimated through histological examination of welded samples. In the first part of the study, results showed that none of the applications was satisfactory. Full-thickness success rates were 28% (2 of 7) for 809-nm and for 980-nm diode lasers and 67% (2 of 3) for 1070-nm YLF and (4 of 6) for 1980-nm Tm:YAP lasers. In the second part of the study, YLF and Tm:YAP lasers were investigated with bigger sample size. Results were not conclusive but promising again. Five corneal incisions were full-thickness welded out of 10 corneas with 1070-nm laser, and 4 corneal incisions were partially welded out of 10 corneas with 1980-nm laser in the second part of the study. Results showed that noteworthy corneal welding could be obtained with 1070-nm YLF laser and 1980-nm Tm:YAP laser wavelengths. Furthermore, in vitro and in vivo studies will shed light on the potential usage of corneal laser welding technique.

  15. Correlation between epithelial thickness in normal corneas, untreated ectatic corneas, and ectatic corneas previously treated with CXL; is overall epithelial thickness a very early ectasia prognostic factor?

    Kanellopoulos AJ

    2012-05-01

    Full Text Available Anastasios John Kanellopoulos,1,2 Ioannis M Aslanides,3 George Asimellis11Laservision Eye Institute, Athens, 2Emmetropia Mediterranean Eye Clinic, Crete, Greece, 3New York University School of Medicine, NY, USAPurpose: To determine and correlate epithelial corneal thickness (pachymetric measurements taken with a digital arc scanning very high frequency ultrasound biomicroscopy (HF UBM imaging system (Artemis-II, and compare mean and central epithelial thickness among normal eyes, untreated keratoconic eyes, and keratoconic eyes previously treated with collagen crosslinking (CXL.Methods: Epithelial pachymetry measurements (topographic mapping were conducted on 100 subjects via HF UBM. Three groups of patients were included: patients with normal eyes (controls, patients with untreated keratoconic eyes, and patients with keratoconic eyes treated with CXL. Central, mean, and peripheral corneal epithelial thickness was examined for each group, and a statistical study was conducted.Results: Mean, central, and peripheral corneal epithelial thickness was compared between the three groups of patients. Epithelium thickness varied substantially in the keratoconic group, and in some cases there was a difference of up to 20 µm between various points of the same eye, and often a thinner epithelium coincided with a thinner cornea. However, on average, data from the keratoconic group suggested an overall thickening of the epithelium, particularly over the pupil center of the order of +3 µm, while the mean epithelium thickness was on average +1.1 µm, compared to the control population (P = 0.005. This overall thickening was more pronounced in younger patients in the keratoconic group. Keratoconic eyes previously treated with CXL showed, on average, virtually the same average epithelium thickness (mean –0.7 µm, –0.2 µm over the pupil center, –0.9 µm over the peripheral zone as the control group. This finding further reinforces our novel theory of the

  16. Safety of intracameral injection of gatifloxacin, levofloxacin on corneal endothelial structure and viability.

    Choi, Jin A; Chung, Sung Kun

    2009-10-01

    To investigate the safety of intracameral injection of gatifloxacin, levofloxacin in a rabbit model as prophylaxis against endophthalmitis. Twenty-four eyes of New Zealand white rabbits were randomly divided into 3 treatment groups: levofloxacin, gatifloxacin, and balanced salt solution (BSS) control groups. After 100 microL of each was injected into the anterior chamber, endothelial toxicity was evaluated by measuring the central corneal thicknesses and the clinical toxicity scores using a slit-lamp at post-procedure days 3 and 7. The percent of dead cells was determined by vital staining with alizarin red and trypan blue at 7 days after injection. Finally, in each group, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed for the evaluation of structural integrity. The toxicity scores were increased at post-procedure days 3 and 7, but the difference among the groups was not statistically significant (P = 0.661, 0.216, respectively). With regard to baseline corneal thickness, only the levofloxacin group exhibited a significant increase from baseline (P = 0.028), whereas the other treatment groups showed no difference from baseline (P = 0.128 in gatifloxacin, 0.161 in BSS group). The mean corneal endothelial damage was 0.81 +/- 0.31% in the levofloxacin group, 0.56 +/- 0.47% in the gatifloxacin group, and 0.53 +/- 0.52% in the BSS group, with no statistically significant difference noted among the groups (P = 0.582). SEM revealed a well-preserved hexagonal endothelial cell mosaic and normal microvilli on the endothelial cell surface in the gatifloxacin and control groups. However, the levofloxacin group showed slightly disintegrated cellular borders. TEM revealed that each group maintained normal intracellular organization, whereas the levofloxacin group exhibited slightly flat cell configuration with irregular folds on the apical cell surface. Intracameral injection of gatifloxacin and levofloxacin was nontoxic in terms of

  17. Combined aerobic and resistance exercise training decreases peripheral but not central artery wall thickness in subjects with type 2 diabetes.

    Schreuder, T.H.A.; Munckhof, I.C.L. van den; Poelkens, F.; Hopman, M.T.; Thijssen, D.H.

    2015-01-01

    OBJECTIVE: Little is known about the impact of exercise training on conduit artery wall thickness in type 2 diabetes. We examined the local and systemic impact of exercise training on superficial femoral (SFA), brachial (BA), and carotid artery (CA) wall thickness in type 2 diabetes patients and

  18. Influence of corneal collagen crosslinking with riboflavin and ultraviolet-a irradiation on excimer laser surgery.

    Kampik, D.; Ralla, B.; Keller, S.; Hirschberg, M.; Friedl, P.H.A.; Geerling, G.

    2010-01-01

    PURPOSE: Riboflavin/ultraviolet A (UVA) cross-linking (CXL) of corneal collagen is a novel method of stabilizing corneal mechanical properties and preventing progression of keratectasias. This study was conducted to investigate whether CXL influences ablation rate, flap thickness, and refractive

  19. New therapeutic modality for corneal endothelial disease using Rho-associated kinase inhibitor eye drops.

    Koizumi, Noriko; Okumura, Naoki; Ueno, Morio; Kinoshita, Shigeru

    2014-11-01

    Corneal endothelial dysfunction accompanied by visual disturbance is a primary indication for corneal endothelial transplantation. However, despite the value and potential of endothelial graft surgery, a strictly pharmacological approach for treating corneal endothelial dysfunction remains an attractive proposition. Previously, we reported that the selective Rho-associated kinase (ROCK) inhibitor Y-27632 promotes cell adhesion and proliferation, and inhibits the apoptosis of primate corneal endothelial cells in culture. These findings have led us to develop a novel medical treatment for the early phase of corneal endothelial disease using ROCK inhibitor eye drops. In rabbit and monkey models of partial endothelial dysfunction, we showed that corneal endothelial wound healing was accelerated via the topical application of ROCK inhibitor to the ocular surface, resulting in the regeneration of a corneal endothelial monolayer with a high endothelial cell density. Based on these animal studies, we are now attempting to advance the clinical application of ROCK inhibitor eye drops for patients with corneal endothelial dysfunction. A pilot clinical study was performed at the Kyoto Prefectural University of Medicine, and the effects of Y-27632 eye drops after transcorneal freezing were evaluated in 8 patients with corneal endothelial dysfunction. We observed a positive effect of ROCK inhibitor eye drops in treating patients with central edema caused by Fuchs corneal endothelial dystrophy. We believe that our new findings will contribute to the establishment of a new approach for the treatment of corneal endothelial dysfunction.

  20. Airbag induced corneal ectasia.

    Mearza, Ali A; Koufaki, Fedra N; Aslanides, Ioannis M

    2008-02-01

    To report a case of airbag induced corneal ectasia. Case report. A patient 3 years post-LASIK developed bilateral corneal ectasia worse in the right eye following airbag deployment in a road traffic accident. At last follow up, best corrected vision was 20/40 with -4.00/-4.00 x 25 in the right eye and 20/25 with -1.25/-0.50 x 135 in the left eye. This is a rare presentation of trauma induced ectasia in a patient post-LASIK. It is possible that reduction in biomechanical integrity of the cornea from prior refractive surgery contributed to this presentation.

  1. Construction of Anterior Hemi-Corneal Equivalents Using Nontransfected Human Corneal Cells and Transplantation in Dog Models.

    Xu, Bin; Song, Zhan; Fan, Tingjun

    2017-11-01

    Tissue-engineered human anterior hemi-cornea (TE-aHC) is a promising equivalent for treating anterior lamellar keratopathy to surmount the severe shortage of donated corneas. This study was intended to construct a functional TE-aHC with nontransfected human corneal stromal (ntHCS) and epithelial (ntHCEP) cells using acellular porcine corneal stromata (aPCS) as a carrier scaffold, and evaluate its biological functions in a dog model. To construct a TE-aHC, ntHCS cells were injected into an aPCS scaffold and cultured for 3 days; then, ntHCEP cells were inoculated onto the Bowman's membrane of the scaffold and cultured for 5 days under air-liquid interface condition. After its morphology and histological structure were characterized, the constructed TE-aHC was transplanted into dog eyes via lamellar keratoplasty. The corneal transparency, thickness, intraocular pressure, epithelial integrity, and corneal regeneration were monitored in vivo, and the histological structure and histochemical property were examined ex vivo 360 days after surgery, respectively. The results showed that the constructed TE-aHC was highly transparent and composed of a corneal epithelium of 7-8 layer ntHCEP cells and a corneal stroma of regularly aligned collagen fibers and well-preserved glycosaminoglycans with sparsely distributed ntHCS cells, mimicking a normal anterior hemi-cornea (aHC). Moreover, both ntHCEP and ntHCS cells maintained positive expression of their marker and functional proteins. After transplantation into dog eyes, the constructed TE-aHC acted naturally in terms of morphology, structure and inherent property, and functioned well in maintaining corneal clarity, thickness, normal histological structure, and composition in dog models by reconstructing a normal aHC, which could be used as a promising aHC equivalent in corneal regenerative medicine and aHC disorder therapy. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  2. Corneal changes with accommodation using dual Scheimpflug photography.

    Sisó-Fuertes, Irene; Domínguez-Vicent, Alberto; del Águila-Carrasco, Antonio; Ferrer-Blasco, Teresa; Montés-Micó, Robert

    2015-05-01

    To assess whether corneal parameters and aberrations are affected by accommodation. Optics Department, University of Valencia, Valencia, Spain. Prospective cross-sectional study. The Galilei G4 dual Scheimpflug device was used to obtain data on the anterior and posterior axial curvatures, total corneal power (TCP), and corneal pachymetry from 3 corneal zones (central: 0.0 up to 4.0 mm; paracentral or mid: 4.0 up to 7.0 mm; peripheral: 7.0 up to 10.0 mm) in young emmetropic eyes in the unaccommodated and 4 accommodated states (from -1.0 to -4.0 diopters [D] in 1.0 D steps). The 2nd-, 3rd-, and 4th-order aberrations as well as the root mean square (RMS) were also determined for the entire cornea at the same accommodative demands. The study evaluated 7 subjects (12 eyes). No significant changes in any measured parameter were found during accommodation for any corneal zone (P > .05). Statistically significant differences were found in the various corneal zones when it was assumed they were constant with accommodation (P the high standard deviation values. Different parameters in various zones of the cornea as well as corneal aberrations were stable during accommodation. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  3. Structure of carbon monoxide time variations in the atmospheric thickness over Central Eurasia (Issyk Kul Monitoring Station)

    Aref'ev, V. N.; Kashin, F. V.; Orozaliev, M. D.; Sizov, N. I.; Sinyakov, V. P.; Sorokina, L. I.

    2013-03-01

    The results of measurements of the CO content in the atmospheric thickness by the method of solar molecular-absorption spectroscopy are presented. Over 87 months of observations, the annual mean CO content decreased by ˜19% at a mean rate of changes equal to -(0.14 ± 0.02) atm cm per year. Maxima and minima of seasonal variations most often fall on February and September, respectively. The mean overall amplitude of changes in the CO content during the annual cycle is about 50% of the mean value. The Fourier analysis revealed variations in the CO composition with periods from 3 to 84 months. A simple statistical model satisfactorily describes time changes in the CO content in the atmospheric thickness. The results of measurements of the CO content in the atmospheric thickness are compared with the data of CO measurements in samples of surface air at stations of the Global Atmospheric Watch.

  4. Spontaneous Corneal Hydrops in a Patient with a Corneal Ulcer

    Hatim Batawi

    2016-01-01

    Full Text Available Purpose: We report the case of a 77-year-old man with no history of keratoconus or other ectatic disorders who presented with corneal hydrops in the setting of a corneal ulcer. The risk factors, pathogenesis and treatment options of corneal hydrops are discussed. Method: This is an observational case report study. Results: A 77-year-old man presented with a 1-day history of severe pain, redness, mucous discharge and photophobia in the right eye. A slit-lamp examination of the right eye showed an area of focal corneal edema and protrusion. Within the area of edema and protrusion, there was an infiltrate with an overlying epithelial defect consistent with an infectious corneal ulcer. The Seidel test showed no leakage, so a clinical diagnosis of corneal hydrops associated with nonperforated corneal ulcer was made. With appropriate antibiotic treatment, the corneal ulcer and hydrops both resolved over a 1-month period. Conclusion: Corneal hydrops can occur in the setting of corneal infections.

  5. Corneal biomechanical properties from air-puff corneal deformation imaging

    Marcos, Susana; Kling, Sabine; Bekesi, Nandor; Dorronsoro, Carlos

    2014-02-01

    The combination of air-puff systems with real-time corneal imaging (i.e. Optical Coherence Tomography (OCT), or Scheimpflug) is a promising approach to assess the dynamic biomechanical properties of the corneal tissue in vivo. In this study we present an experimental system which, together with finite element modeling, allows measurements of corneal biomechanical properties from corneal deformation imaging, both ex vivo and in vivo. A spectral OCT instrument combined with an air puff from a non-contact tonometer in a non-collinear configuration was used to image the corneal deformation over full corneal cross-sections, as well as to obtain high speed measurements of the temporal deformation of the corneal apex. Quantitative analysis allows direct extraction of several deformation parameters, such as apex indentation across time, maximal indentation depth, temporal symmetry and peak distance at maximal deformation. The potential of the technique is demonstrated and compared to air-puff imaging with Scheimpflug. Measurements ex vivo were performed on 14 freshly enucleated porcine eyes and five human donor eyes. Measurements in vivo were performed on nine human eyes. Corneal deformation was studied as a function of Intraocular Pressure (IOP, 15-45 mmHg), dehydration, changes in corneal rigidity (produced by UV corneal cross-linking, CXL), and different boundary conditions (sclera, ocular muscles). Geometrical deformation parameters were used as input for inverse finite element simulation to retrieve the corneal dynamic elastic and viscoelastic parameters. Temporal and spatial deformation profiles were very sensitive to the IOP. CXL produced a significant reduction of the cornea indentation (1.41x), and a change in the temporal symmetry of the corneal deformation profile (1.65x), indicating a change in the viscoelastic properties with treatment. Combining air-puff with dynamic imaging and finite element modeling allows characterizing the corneal biomechanics in-vivo.

  6. Topical administration of orbital fat-derived stem cells promotes corneal tissue regeneration.

    Lin, Ko-Jo; Loi, Mei-Xue; Lien, Gi-Shih; Cheng, Chieh-Feng; Pao, Hsiang-Yin; Chang, Yun-Chuang; Ji, Andrea Tung-Qian; Ho, Jennifer Hui-Chun

    2013-06-14

    Topical administration of eye drops is the major route for drug delivery to the cornea. Orbital fat-derived stem cells (OFSCs) possess an in vitro corneal epithelial differentiation capacity. Both the safety and immunomodulatory ability of systemic OFSC transplantation were demonstrated in our previous work. In this study, we investigated the safety, therapeutic effect, and mechanism(s) of topical OFSC administration in an extensive alkali-induced corneal wound. Corneal injury was created by contact of a piece of 0.5 N NaOH-containing filter paper on the corneal surface of a male Balb/c mouse for 30 s. The area of the filter paper covered the central 70% or 100% of the corneal surface. OFSCs (2 × 10(5)) in 5 μl phosphate-buffered saline (PBS) were given by topical administration (T) twice a day or by two intralimbal (IL) injections in the right cornea, while 5 μl of PBS in the left cornea served as the control. Topical OFSCs promoted corneal re-epithelialization of both the limbal-sparing and limbal-involved corneal wounds. In the first three days, topical OFSCs significantly reduced alkali-induced corneal edema and stromal infiltration according to a histopathological examination. Immunohistochemistry and immunofluorescence staining revealed that transplanted cells were easily detectable in the corneal epithelium, limbal epithelium and stroma, but only some of transplanted cells at the limbal epithelium had differentiated into cytokeratin 3-expressing cells. OFSCs did not alter neutrophil (Ly6G) levels in the cornea, but significantly reduced macrophage (CD68) infiltration and inducible nitrous oxide synthetase (iNOS) production during acute corneal injury as quantified by a Western blot analysis. Continuous topical administration of OFSCs for seven days improved corneal transparency, and this was accompanied by diffuse stromal engraftment of transplanted cells and differentiation into p63-expressing cells at the limbal area. The therapeutic effect of the

  7. Topical administration of orbital fat-derived stem cells promotes corneal tissue regeneration

    2013-01-01

    Introduction Topical administration of eye drops is the major route for drug delivery to the cornea. Orbital fat-derived stem cells (OFSCs) possess an in vitro corneal epithelial differentiation capacity. Both the safety and immunomodulatory ability of systemic OFSC transplantation were demonstrated in our previous work. In this study, we investigated the safety, therapeutic effect, and mechanism(s) of topical OFSC administration in an extensive alkali-induced corneal wound. Methods Corneal injury was created by contact of a piece of 0.5 N NaOH-containing filter paper on the corneal surface of a male Balb/c mouse for 30 s. The area of the filter paper covered the central 70% or 100% of the corneal surface. OFSCs (2 × 105) in 5 μl phosphate-buffered saline (PBS) were given by topical administration (T) twice a day or by two intralimbal (IL) injections in the right cornea, while 5 μl of PBS in the left cornea served as the control. Results Topical OFSCs promoted corneal re-epithelialization of both the limbal-sparing and limbal-involved corneal wounds. In the first three days, topical OFSCs significantly reduced alkali-induced corneal edema and stromal infiltration according to a histopathological examination. Immunohistochemistry and immunofluorescence staining revealed that transplanted cells were easily detectable in the corneal epithelium, limbal epithelium and stroma, but only some of transplanted cells at the limbal epithelium had differentiated into cytokeratin 3-expressing cells. OFSCs did not alter neutrophil (Ly6G) levels in the cornea, but significantly reduced macrophage (CD68) infiltration and inducible nitrous oxide synthetase (iNOS) production during acute corneal injury as quantified by a Western blot analysis. Continuous topical administration of OFSCs for seven days improved corneal transparency, and this was accompanied by diffuse stromal engraftment of transplanted cells and differentiation into p63-expressing cells at the limbal area. The

  8. The Steroids for Corneal Ulcers Trial

    Srinivasan, Muthiah; Mascarenhas, Jeena; Rajaraman, Revathi; Ravindran, Meenakshi; Lalitha, Prajna; Glidden, David V.; Ray, Kathryn J.; Hong, Kevin C.; Oldenburg, Catherine E.; Lee, Salena M.; Zegans, Michael E.; McLeod, Stephen D.; Lietman, Thomas M.; Acharya, Nisha R.

    2013-01-01

    Objectives To provide comprehensive trial methods and baseline data for the Steroids for Corneal Ulcers Trial and to present epidemiological characteristics such as risk factors, causative organisms, and ulcer severity. Methods Baseline data from a 1:1 randomized, placebo-controlled, double-masked clinical trial comparing prednisolone phosphate, 1%, with placebo as adjunctive therapy for the treatment of bacterial corneal ulcers. Eligible patients had a culture-positive bacterial corneal ulcer and had been taking moxifloxacin for 48 hours. The primary outcome for the trial is best spectacle-corrected visual acuity at 3 months from enrollment. This report provides comprehensive baseline data, including best spectacle-corrected visual acuity, infiltrate size, microbio-logical results, and patient demographics, for patients enrolled in the trial. Results Of 500 patients enrolled, 97% were in India. Two hundred twenty patients (44%) were agricultural workers. Median baseline visual acuity was 0.84 logMAR (Snellen, 20/125) (interquartile range, 0.36-1.7; Snellen, 20/50 to counting fingers). Baseline visual acuity was not significantly different between the United States and India. Ulcers in India had larger infiltrate/scar sizes (P=.04) and deeper infiltrates (P=.04) and were more likely to be localized centrally (P=.002) than ulcers enrolled in the United States. Gram-positive bacteria were the most common organisms isolated from the ulcers (n=366, 72%). Conclusions The Steroids for Corneal Ulcers Trial will compare the use of a topical corticosteroid with placebo as adjunctive therapy for bacterial corneal ulcers. Patients enrolled in this trial had diverse ulcer severity and on average significantly reduced visual acuity at presentation. PMID:21987581

  9. Comparative Study of Anterior Eye Segment Measurements with Spectral Swept-Source and Time-Domain Optical Coherence Tomography in Eyes with Corneal Dystrophies.

    Nowinska, Anna K; Teper, Sławomir J; Janiszewska, Dominika A; Lyssek-Boron, Anita; Dobrowolski, Dariusz; Koprowski, Robert; Wylegala, Edward

    2015-01-01

    To compare anterior eye segment measurements and morphology obtained with two optical coherence tomography systems (TD OCT, SS OCT) in eyes with corneal dystrophies (CDs). Fifty healthy volunteers (50 eyes) and 54 patients (96 eyes) diagnosed with CD (epithelial basement membrane dystrophy, EBMD = 12 eyes; Thiel-Behnke CD = 6 eyes; lattice CD TGFBI type = 15 eyes; granular CD type 1 = 7 eyes, granular CD type 2 = 2 eyes; macular CD = 23 eyes; and Fuchs endothelial CD = 31 eyes) were recruited for the study. Automated and manual central corneal thickness (aCCT, mCCT), anterior chamber depth (ACD), and nasal and temporal trabecular iris angle (nTIA, tTIA) were measured and compared with Bland-Altman plots. Good agreement between the TD and SS OCT measurements was demonstrated for mCCT and aCCT in normal individuals and for mCCT in the CDs group. The ACD, nTIA, and tTIA measurements differed significantly in both groups. TBCD, LCD, and FECD caused increased CCT. MCD caused significant corneal thinning. FECD affected all analyzed parameters. Better agreement between SS OCT and TD OCT measurements was demonstrated in normal individuals compared to the CDs group. OCT provides comprehensive corneal deposits analysis and demonstrates the association of CD with CCT, ACD, and TIA measurements.

  10. Comparative Study of Anterior Eye Segment Measurements with Spectral Swept-Source and Time-Domain Optical Coherence Tomography in Eyes with Corneal Dystrophies

    Anna K. Nowinska

    2015-01-01

    Full Text Available Purpose. To compare anterior eye segment measurements and morphology obtained with two optical coherence tomography systems (TD OCT, SS OCT in eyes with corneal dystrophies (CDs. Methods. Fifty healthy volunteers (50 eyes and 54 patients (96 eyes diagnosed with CD (epithelial basement membrane dystrophy, EBMD = 12 eyes; Thiel-Behnke CD = 6 eyes; lattice CD TGFBI type = 15 eyes; granular CD type 1 = 7 eyes, granular CD type 2 = 2 eyes; macular CD = 23 eyes; and Fuchs endothelial CD = 31 eyes were recruited for the study. Automated and manual central corneal thickness (aCCT, mCCT, anterior chamber depth (ACD, and nasal and temporal trabecular iris angle (nTIA, tTIA were measured and compared with Bland-Altman plots. Results. Good agreement between the TD and SS OCT measurements was demonstrated for mCCT and aCCT in normal individuals and for mCCT in the CDs group. The ACD, nTIA, and tTIA measurements differed significantly in both groups. TBCD, LCD, and FECD caused increased CCT. MCD caused significant corneal thinning. FECD affected all analyzed parameters. Conclusions. Better agreement between SS OCT and TD OCT measurements was demonstrated in normal individuals compared to the CDs group. OCT provides comprehensive corneal deposits analysis and demonstrates the association of CD with CCT, ACD, and TIA measurements.

  11. Changes in corneal epithelial layer inflammatory cells in aqueous tear-deficient dry eye.

    Lin, Hui; Li, Wei; Dong, Nuo; Chen, Wensheng; Liu, Jing; Chen, Lelei; Yuan, Hongxia; Geng, Zhixin; Liu, Zuguo

    2010-01-01

    To investigate the morphology, distribution, and density of inflammatory cells in the corneal epithelium of aqueous tear-deficient dry eye. Thirty-two patients with non-Sjögren's syndrome (NSS) dry eye, 14 patients with Sjögren's syndrome (SS) dry eye, and 33 healthy volunteers were studied. In vivo laser scanning confocal microscopy was used to investigate both Langerhans cell (LCs) and leukocyte distribution and density in the peripheral and central corneal epithelium. LC morphology was also evaluated. Multifactor regression analysis assessed whether there is a correlation between clinical manifestations and inflammatory cell densities. LCs were present in both central (34.9 +/- 5.7 cells/mm(2)) and peripheral (90.7 +/- 8.2 cells/mm(2)) parts of the normal corneal epithelium. Moreover, LC density increased dramatically in the central corneal epithelium in patients with NSS (89.8 +/- 10.8 cells/mm(2)) and SS (127.9 +/- 23.7 cells/mm(2)). The ratio of LCs with obvious processes was much higher in patients with dry eye than in healthy volunteers. LC density also increased in peripheral corneal epithelium in patients with SS, but not in those with NSS. Leukocyte density in normal corneal epithelium was very low, whereas it increased in the central corneal epithelium (4.6 +/- 1.0 cells/mm(2)) in NSS and in both central (49.0 +/- 12.9 cells/mm(2)) and peripheral (84.2 +/- 36.8 cells/mm(2)) corneal epithelium in SS. Densities of LCs and leukocytes showed significant correlation with the severity found in clinical evaluation. The LC and leukocyte changes in the corneal epithelium suggest their involvement in aqueous tear-deficient dry eye pathophysiology. In vivo dynamic assessment of central corneal inflammatory cell density may serve as an indicator of dry eye severity and provide new insight for dry eye treatment.

  12. Neurotrophic corneal and conjunctival xerosis

    Svetlana Gennadyevna Zhurova

    2014-03-01

    Full Text Available Purpose: to develop a method of surgical treatment of patients with corneal ulcers of xerotic etiology and evaluate its efficacy in different time periods after operation. Materials and methods: 68 patients (86 eyes with severe dry eye syndrome complicated by xerotic corneal ulcers were examined. In all patients, the ulcer defect was covered with conjunctiva and amniotic membrane. The operation was combined with an outer tarsorrhaphy and temporary blepharorraphy. Results: All 86 eyes (100% achieved total closure of the ulcer defect, sealing of any perforation and maintaining of corneal transparency beyond the ulcer defect. Conclusion: Surgical closure of corneal ulcers with conjunctiva is an effective method of treatment of xerotic corneal ulcers. It could be recommended in patients with corneal perforation and tendency of descemetocele formation.

  13. Corneal Neurotoxicity Due to Topical Benzalkonium Chloride

    Sarkar, Joy; Chaudhary, Shweta; Namavari, Abed; Ozturk, Okan; Chang, Jin-Hong; Yco, Lisette; Sonawane, Snehal; Khanolkar, Vishakha; Hallak, Joelle; Jain, Sandeep

    2012-01-01

    Topical application of benzalkonium chloride (BAK) to the eye causes dose-related corneal neurotoxicity. Corneal inflammation and reduction in aqueous tear production accompany neurotoxicity. Cessation of BAK treatment leads to recovery of corneal nerve density.

  14. Contact Lens Related Corneal Ulcer

    Loh, KY; Agarwal, P

    2010-01-01

    A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are: overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. Th...

  15. Conventional Corneal Collagen Cross-Linking Versus Transepithelial Diluted Alcohol and Iontophoresis-Assisted Corneal Cross-Linking in Progressive Keratoconus.

    Bilgihan, Kamil; Yesilirmak, Nilufer; Altay, Yesim; Yuvarlak, Armagan; Ozdemir, Huseyin Baran

    2017-12-01

    To compare clinical outcomes of conventional corneal cross-linking (C-CXL) and diluted alcohol and iontophoresis-assisted corneal cross-linking (DAI-CXL) for the treatment of progressive keratoconus (KC). Ninety-three eyes of 80 patients with KC were treated by C-CXL (n = 47) or DAI-CXL (n = 46). Visual acuity, keratometry, KC indexes, pachymetry, and aberrations were recorded before treatment and 1, 3, 6, and 12 months after treatment. The demarcation line was assessed 1 month after treatment. A significant improvement in visual acuity was observed at month 3 and month 6 after DAI-CXL and C-CXL, respectively. A significant decrease in maximum keratometry was observed in both groups at month 6. The front symmetry index significantly improved in both groups after 6 months, whereas the Baiocchi Calossi Versaci index significantly improved only after DAI-CXL at month 12 (P = 0.01). Average keratometry and other KC indexes were stable during 12 months of follow-up. Central corneal thickness decreased by 28.6 and 40.2 μm after DAI-CXL and C-CXL at month 1, respectively (P < 0.01), and it reached baseline at the 12th month (P = 0.14) only in the DAI-CXL group. Higher-order aberrations, coma, and spherical aberration significantly worsened at month 1 (P < 0.01) only after C-CXL; however, they improved significantly at month 12 compared with baseline (P < 0.05) in both groups. The demarcation line was visible in all cases at month 1 at a mean depth of 302 ± 56 μm and 311 ± 57 μm after DAI-CXL and C-CXL, respectively (P = 0.7). The DAI-CXL protocol seems as effective as the C-CXL protocol in halting KC progression after 1 year of follow-up.

  16. Corneal endothelial cell changes after cataract surgery in patients on systemic sympathetic α-1a antagonist medication (tamsulosin).

    Storr-Paulsen, Allan; Jørgensen, Jesper Skovlund; Norregaard, Jens Christian; Thulesen, Jesper

    2014-06-01

      The purpose of this study was to assess the incidence of intraoperative floppy iris syndrome (IFIS) and the morphology of the corneal endothelium after cataract extraction in Caucasian male patients exposed to the α-1a adrenergic receptor antagonist tamsulosin.   In a clinical prospective study, 23 male patients (23 eyes) treated with tamsulosin due to benign prostatic hyperplasia and 25 male patients (25 eyes) with no tamsulosin treatment had cataract surgery. The divide-and-conquer technique was used with the Infinity OZil(®) machine. A combination of Healon and Healon5 was used in all patients, but the use of additional Vision Blue, iris retractors or intracameral phenylephrine in the tamsulosin group was at the discretion of the surgeon. The endothelial cell density, variation in endothelial cell size (CV), percentage of hexagonal cells and central corneal thickness (CCT) were recorded at baseline and at 3 months postoperatively.   In the tamsulosin-treated group, 19 of 23 eyes (83%) developed IFIS, compared with no IFIS in the control group. Compared with the control group, the tamsulosin group showed significantly less dilatation at the start of the operation, significant miosis during surgery and significantly greater corneal endothelial cell loss 3 months postoperatively (12% versus 3%; ptamsulosin-treated male patients. Patients on tamsulosin showed less preoperative dilatation, significant miosis during surgery, and had significantly greater postoperative endothelial cell loss compared with nontreated patients despite recommended precautions. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by Blackwell Publishing Ltd.

  17. Validation of Na,K-ATPase pump function of corneal endothelial cells for corneal regenerative medicine.

    Hatou, Shin; Higa, Kazunari; Inagaki, Emi; Yoshida, Satoru; Kimura, Erika; Hayashi, Ryuhei; Tsujikawa, Motokazu; Tsubota, Kazuo; Nishida, Kohji; Shimmura, Shigeto

    2013-12-01

    Tissue-engineering approaches to cultivate corneal endothelial cells (CECs) or induce CECs from stem cells are under investigation for the treatment of endothelial dysfunction. Before clinical application, a validation method to determine the quality of these cells is required. In this study, we quantified the endothelial pump function required for maintaining the corneal thickness using rabbit CECs (RCECs) and a human CEC line (B4G12). The potential difference of RCECs cultured on a permeable polyester membrane (Snapwell), B4G12 cells on Snapwell, or B4G12 cells on a collagen membrane (CM6) was measured by an Ussing chamber system, and the effect of different concentrations of ouabain (Na,K-ATPase specific inhibitor) was obtained. A mathematical equation derived from the concentration curve revealed that 2 mM ouabain decreases pump function of RCECs to 1.0 mV, and 0.6 mM ouabain decreases pump function of B4G12 on CM6 to 1.0 mV. Ouabain injection into the anterior chamber of rabbit eyes at a concentration of pump function >1.0 mV is required to maintain the corneal thickness. These results can be used for standardization of CEC pump function and validation of tissue-engineered CEC sheets for clinical use.

  18. Functional genomics reveals an essential and specific role for Stat1 in protection of the central nervous system following herpes simplex virus corneal infection.

    Pasieka, Tracy Jo; Cilloniz, Cristian; Carter, Victoria S; Rosato, Pamela; Katze, Michael G; Leib, David A

    2011-12-01

    Innate immune deficiencies result in a spectrum of severe clinical outcomes following infection. In particular, there is a strong association between loss of the signal transducer and activator of transcription (Stat) pathway, breach of the blood-brain barrier (BBB), and virus-induced neuropathology. The gene signatures that characterize resistance, disease, and mortality in the virus-infected nervous system have not been defined. Herpes simplex virus type 1 (HSV-1) is commonly associated with encephalitis in humans, and humans and mice lacking Stat1 display increased susceptibility to HSV central nervous system (CNS) infections. In this study, two HSV-1 strains were used, KOS (wild type [WT]), and Δvhs, an avirulent recombinant lacking the virion host shutoff (vhs) function. In addition, two mouse strains were used: strain 129 (control) and a Stat1-deficient (Stat1(-/-)) strain. Using combinations of these virus and mouse strains, we established a model of infection resulting in three different outcomes: viral clearance without neurological disease (Δvhs infection of control mice), neurological disease followed by viral clearance (Δvhs infection of Stat1(-/-) mice and WT infection of control mice), or neurological disease followed by death (WT infection of Stat1(-/-) mice). Through the use of functional genomics on the infected brain stems, we determined gene signatures that were representative of the three infection outcomes. We demonstrated a pathological signature in the brain stem of Stat1-deficient mice characterized by upregulation of transcripts encoding chemokine receptors, inflammatory markers, neutrophil chemoattractants, leukocyte adhesion proteins, and matrix metalloproteases. Additionally, there was a greater than 100-fold increase in the inflammatory markers interleukin 1β (IL-1β) and IL-6. Consistent with this gene signature, we demonstrated profound CNS inflammation with a concomitant lethal breach of the BBB. Taken together, our results

  19. Dynamic corneal deformation response and integrated corneal tomography

    Marcella Q Salomão

    2018-01-01

    Full Text Available Measuring corneal biomechanical properties is still challenging. There are several clinical applications for biomechanical measurements, including the detection of mild or early forms of ectatic corneal diseases. This article reviews clinical applications for biomechanical measurements provided by the Corvis ST dynamic non contact tonometer

  20. Analysis of the learning curve for pre-cut corneal specimens in preparation for lamellar transplantation: a prospective, single-centre, consecutive case series prepared at the Lions New South Wales Eye Bank.

    Martin, Aifric Isabel; Devasahayam, Rajnesh; Hodge, Christopher; Cooper, Simon; Sutton, Gerard L

    2017-09-01

    This study is the first paper to establish a learning curve by a single technician. Preparation of pre-cut corneal endothelial grafts commenced at Lions New South Wales Eye Bank in December 2014. The primary objective of this study was to review the safety and reliability of the preparation method during the first year of production. This is a hospital-based, prospective case series. There were 234 consecutive donor corneal lenticules. Donor lenticules were prepared by a single operator using a linear cutting microkeratome. Immediately prior to cutting, central corneal thickness values were recorded. Measurements of the corneal bed were taken immediately following lenticule preparation. Outcomes were separated by blade sizes, and intended thickness was compared to actual thickness for each setting. Early specimens were compared to later ones to assess for a learning curve within the technique. The main parameter measured is the mean difference from intended lamellar cut thickness. The mean final cut thickness was 122.36 ± 20.35 μm, and the mean difference from intended cut was 30.17 ± 37.45 μm. No significant difference was found between results achieved with early specimens versus those achieved with later specimens (P = 0.425). Thin, reproducible endothelial grafts can routinely be produced by trained technicians at their respective eye banks without significant concerns for an extended learning curve. This service can reduce perioperative surgical complexity, required surgical paraphernalia and theatre times. The consistent preparation of single-pass, ultrathin pre-cut corneas may have additional advantages for surgeons seeking to introduce lamellar techniques. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

  1. Intraocular pressure measurements and corneal biomechanical properties using a dynamic Scheimpflug analyzer, after several keratoplasty techniques, versus normal eyes.

    Hugo, J; Granget, E; Ho Wang Yin, G; Sampo, M; Hoffart, L

    2018-01-01

    To evaluate the biomechanical properties of the cornea and their impact on intraocular pressure (IOP) measurement after lamellar keratoplasty, compared to healthy eyes, using a non-contact tonometer with a Scheimpflug camera. This study, from 2014 to 2015, included 22 primary DSAEK, 5 DALK, 6 DSAEK after PK, and 50 control eyes. Using a non-contact tonometer with a high-speed Scheimpflug camera (CORVIS ST, Oculus Optikgeräte GmbH, Wetzlar, Germany), several biomechanical parameters were recorded, including radius at highest concavity (R hc ) and defomation amplitude (DA). Central corneal thickness (CCT) and uncorrected IOP, were also recorded. For the control eyes only, a corrected IOP was calculated, based on age, central corneal thickness, and biomechanical parameters. R hc was significantly lower after DALK (R hc =5.54±0.71, P=0.007) and DSAEK (R hc =6.26±0.77, P=0.042) compared to control eyes (R hc =6.82±0.76). DA was higher after DALK and DSAEK, but not significantly (respectively 1.24±0.09 P=0.41 and 1.22±0.15, P=0.923) compared to normal eyes (1.18±0.15). Uncorrected IOP was not significantly different between post-keratoplasty and control eyes. In control eyes, the corrected IOP (15.23±1.88) was lower than the uncorrected IOP (16.10±2.34); a statistically significant positive correlation between R hc and CCT (R 2 =0.6020, P<0001), and a significant negative correlation between DA and CCT (R 2 =-0.641, P<0.0001) were found. Our study showed that, after lamellar keratoplasty, corneal biomechanics are altered. Corneas with higher ocular rigidity will show a lower DA and a higher R hc . Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Laser thermokeratoplasty after lamellar corneal cutting.

    Ismail, M M; Pérez-Santonja, J J; Alió, J L

    1999-02-01

    To evaluate the effect of laser thermokeratoplasty (LTK) in eyes that previously had a lamellar corneal cut. University of Al-Azhar, Cairo, Egypt, and Instituto Oftalmológico de Alicante, Spain. In 15 eyes (10 patients), noncontact LTK was applied 6 to 8 weeks after a lamellar corneal cut had been made. Central pachymetry, keratometry, and videokeratography were performed and uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), and manifest and cycloplegic refractions measured before and 1, 6, 12, and 18 months after LTK. Mean follow-up was 19.13 months. Mean refraction was +5.93 diopters (D) +/- 1.9 (SD) before LTK and -0.43 +/- 1.5 D at 1 month, +1.63 +/- 1.6 D at 6 months, 1.91 +/- 1.41 at 12 months, and +2.01 +/- 1.5 D at the end of the study. Total regression did not occur in any case. Mean BSCVA before LTK was 0.66 +/- 0.2, and spontaneous visual acuity at the end of the study was 0.58 +/- 0.18. No patient lost any lines of preoperative BSCVA. There was no significant difference between the results at 12 months and at the end of the study. Corneal lamellar cutting appeared to improve the magnitude of the refractive effect of noncontact LTK and to decrease the amount of regression.

  3. Correlation between epithelial thickness in normal corneas, untreated ectatic corneas, and ectatic corneas previously treated with CXL; is overall epithelial thickness a very early ectasia prognostic factor?

    Kanellopoulos, Anastasios John; Aslanides, Ioannis M; Asimellis, George

    2012-01-01

    To determine and correlate epithelial corneal thickness (pachymetric) measurements taken with a digital arc scanning very high frequency ultrasound biomicroscopy (HF UBM) imaging system (Artemis-II), and compare mean and central epithelial thickness among normal eyes, untreated keratoconic eyes, and keratoconic eyes previously treated with collagen crosslinking (CXL). Epithelial pachymetry measurements (topographic mapping) were conducted on 100 subjects via HF UBM. Three groups of patients were included: patients with normal eyes (controls), patients with untreated keratoconic eyes, and patients with keratoconic eyes treated with CXL. Central, mean, and peripheral corneal epithelial thickness was examined for each group, and a statistical study was conducted. Mean, central, and peripheral corneal epithelial thickness was compared between the three groups of patients. Epithelium thickness varied substantially in the keratoconic group, and in some cases there was a difference of up to 20 μm between various points of the same eye, and often a thinner epithelium coincided with a thinner cornea. However, on average, data from the keratoconic group suggested an overall thickening of the epithelium, particularly over the pupil center of the order of +3 μm, while the mean epithelium thickness was on average +1.1 μm, compared to the control population (P = 0.005). This overall thickening was more pronounced in younger patients in the keratoconic group. Keratoconic eyes previously treated with CXL showed, on average, virtually the same average epithelium thickness (mean -0.7 μm, -0.2 μm over the pupil center, -0.9 μm over the peripheral zone) as the control group. This finding further reinforces our novel theory of the "reactive" component of epithelial thickening in corneas that are biomechanically unstable, becoming stable when biomechanical rigidity is accomplished despite persistence of cornea topographic irregularity. A highly irregular epithelium may be

  4. Die spacer thickness reproduction for central incisor crown fabrication with combined computer-aided design and 3D printing technology: an in vitro study.

    Hoang, Lisa N; Thompson, Geoffrey A; Cho, Seok-Hwan; Berzins, David W; Ahn, Kwang Woo

    2015-05-01

    The inability to control die spacer thickness has been reported. However, little information is available on the congruency between the computer-aided design parameters for die spacer thickness and the actual printout. The purpose of this study was to evaluate the accuracy and precision of the die spacer thickness achieved by combining computer-aided design and 3-dimensional printing technology. An ivorine maxillary central incisor was prepared for a ceramic crown. The prepared tooth was duplicated by using polyvinyl siloxane duplicating silicone, and 80 die-stone models were produced from Type IV dental stone. The dies were randomly divided into 5 groups with assigned die spacer thicknesses of 25 μm, 45 μm, 65 μm, 85 μm, and 105 μm (n=16). The printed resin copings, obtained from a printer (ProJet DP 3000; 3D Systems), were cemented onto their respective die-stone models with self-adhesive resin cement and stored at room temperature until sectioning into halves in a buccolingual direction. The internal gap was measured at 5 defined locations per side of the sectioned die. Images of the printed resin coping/die-stone model internal gap dimensions were obtained with an inverted bright field metallurgical microscope at ×100 magnification. The acquired digital image was calibrated, and measurements were made using image analysis software. Mixed models (α=.05) were used to evaluate accuracy. A false discovery rate at 5% was used to adjust for multiple testing. Coefficient of variation was used to determine the precision for each group and was evaluated statistically with the Wald test (α=.05). The accuracy, expressed in terms of the mean differences between the prescribed die spacer thickness and the measured internal gap (standard deviation), was 50 μm (11) for the 25 μm group simulated die spacer thickness, 30 μm (10) for the 45 μm group, 15 μm (14) for the 65 μm group, 3 μm (23) for the 85 μm group, and -10 μm (32) for the 105 μm group. The

  5. Role of corneal collagen fibrils in corneal disorders and related pathological conditions

    Hong-Yan Zhou

    2017-05-01

    Full Text Available The cornea is a soft tissue located at the front of the eye with the principal function of transmitting and refracting light rays to precisely sense visual information. Corneal shape, refraction, and stromal stiffness are to a large part determined by corneal fibrils, the arrangements of which define the corneal cells and their functional behaviour. However, the modality and alignment of native corneal collagen lamellae are altered in various corneal pathological states such as infection, injury, keratoconus, corneal scar formation, and keratoprosthesis. Furthermore, corneal recuperation after corneal pathological change is dependent on the balance of corneal collagen degradation and contraction. A thorough understanding of the characteristics of corneal collagen is thus necessary to develop viable therapies using the outcome of strategies using engineered corneas. In this review, we discuss the composition and distribution of corneal collagens as well as their degradation and contraction, and address the current status of corneal tissue engineering and the progress of corneal cross-linking.

  6. Reconstruction of limbal stem cell deficient corneal surface with induced human bone marrow mesenchymal stem cells on amniotic membrane.

    Rohaina, Che Man; Then, Kong Yong; Ng, Angela Min Hwei; Wan Abdul Halim, Wan Haslina; Zahidin, Aida Zairani Mohd; Saim, Aminuddin; Idrus, Ruszymah B H

    2014-03-01

    The cornea can be damaged by a variety of clinical disorders or chemical, mechanical, and thermal injuries. The objectives of this study were to induce bone marrow mesenchymal stem cells (BMSCs) to corneal lineage, to form a tissue engineered corneal substitute (TEC) using BMSCs, and to treat corneal surface defects in a limbal stem cell deficiency model. BMSCs were induced to corneal lineage using limbal medium for 10 days. Induced BMSCs demonstrated upregulation of corneal stem cell markers; β1-integrin, C/EBPδ, ABCG2, and p63, increased protein expression of CK3 and p63 significantly compared with the uninduced ones. For TEC formation, passage 1 BMSCs were trypsinized and seeded on amniotic membrane in a transwell co-culture system and were grown in limbal medium. Limbal stem cell deficiency models were induced by alkaline injury, and the TEC was implanted for 8 weeks. Serial slit lamp evaluation revealed remarkable improvement in corneal regeneration in terms of corneal clarity and reduced vascularization. Histologic and optical coherence tomography analyses demonstrated comparable corneal thickness and achieved stratified epithelium with a compact stromal layer resembling that of normal cornea. CK3 and p63 were expressed in the newly regenerated cornea. In conclusion, BMSCs can be induced into corneal epithelial lineage, and these cells are viable for the formation of TEC, to be used for the reconstruction of the corneal surface in the limbal stem cell deficient model. Copyright © 2014 Mosby, Inc. All rights reserved.

  7. Corneal Collagen Crosslinking Combined with Phototherapeutic Keratectomy and Photorefractive Keratectomy for Corneal Ectasia after Laser in situ Keratomileusis.

    Zhu, Wei; Han, Yunfei; Cui, Changxia; Xu, Wenwen; Wang, Xuan; Dou, Xiaoxiao; Xu, Linlin; Xu, Yanyun; Mu, Guoying

    2018-01-01

    The aim of this study was to analyze the effects of corneal crosslinking (CXL) combined with phototherapeutic keratectomy (PTK) and photorefractive keratectomy (PRK) in halting the progression and improving the visual function of corneal ectasia after laser in situ keratomileusis (LASIK). PTK-PRK-CXL was performed on 14 eyes of 14 patients who developed corneal ectasia after LASIK. The visual acuity, spherical refraction and cylinder, corneal topography indices, thinnest corneal thickness (TCT), and endothelial cell count were evaluated at baseline and at 1, 3, 6, and 12 months postoperatively. The mean uncorrected visual acuity improved significantly from 0.64 ± 0.36 logMAR preoperatively to 0.19 ± 0.12 logMAR at 12 months of follow-up (p 0.05) beyond 6 months after treatment. PTK-PRK-CXL is a promising procedure to halt the progression of post-LASIK keratectasia with significant visual quality improvement. © 2018 S. Karger AG, Basel.

  8. Hyperplastic corneal pannus: an immunohistochemical analysis and review.

    Jakobiec, Frederick A; Stacy, Rebecca C; Mendoza, Pia R; Chodosh, James

    2014-01-01

    An exuberant corneal pannus usually develops in adults with a history of surgery or trauma in the anterior central stroma and appears as a glistening, vascularized, moderately elevated, well circumscribed white nodule. We describe a 78-year-old woman with such a pannus, which in the past has typically been referred to as keloidal or hypertrophic. The involved eye had only light perception, and she underwent a penetrating keratoplasty that improved her vision to 20/100. Histopathologic and immunohistochemical evaluations of a the specimen disclosed a reactive spindle cell stromal proliferation of myofibroblasts that were smooth muscle actin positive with a low Ki67 proliferation index. Desmin, caldesmon, and calponin were negative, in keeping with the incomplete myofilamentary differentiation of a myofibroblast. There was a generous admixture of CD68/163-positive histiocytes and dispersed C3/5-positive T-lymphocytes. An absence of CD138- and IgG4-positive plasma cells ruled out an IgG4-related disease. For a lesion to be keloidal, the collagen must have a thick hyaline character, sharp edges, and a sparsity of intervening cells and vessels. A hypertrophic pannus would be composed of large swollen cells not necessarily increased in number. We therefore recommend adoption of the term hyperplastic for lesions like that described here because of the obvious increase in cellularity from proliferating myofibroblasts and the lack of true keloidal collagen. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Corneal structure and transparency

    Meek, Keith M.; Knupp, Carlo

    2015-01-01

    The corneal stroma plays several pivotal roles within the eye. Optically, it is the main refracting lens and thus has to combine almost perfect transmission of visible light with precise shape, in order to focus incoming light. Furthermore, mechanically it has to be extremely tough to protect the inner contents of the eye. These functions are governed by its structure at all hierarchical levels. The basic principles of corneal structure and transparency have been known for some time, but in recent years X-ray scattering and other methods have revealed that the details of this structure are far more complex than previously thought and that the intricacy of the arrangement of the collagenous lamellae provides the shape and the mechanical properties of the tissue. At the molecular level, modern technologies and theoretical modelling have started to explain exactly how the collagen fibrils are arranged within the stromal lamellae and how proteoglycans maintain this ultrastructure. In this review we describe the current state of knowledge about the three-dimensional stromal architecture at the microscopic level, and about the control mechanisms at the nanoscopic level that lead to optical transparency. PMID:26145225

  10. Surgical therapies for corneal perforations: 10 years of cases in a tertiary referral hospital

    Yokogawa H

    2014-10-01

    Full Text Available Hideaki Yokogawa, Akira Kobayashi, Natsuko Yamazaki, Toshinori Masaki, Kazuhisa Sugiyama Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, JapanPurpose: To report surgical therapies for corneal perforations in a tertiary referral hospital.Methods: Thirty-one eyes of 31 patients (aged 62.4±18.3 years with surgically treated corneal perforations from January 2002 to July 2013 were included in this study. Demographic data such as cause of corneal perforation, surgical procedures, and visual outcomes were retrospectively analyzed.Results: The causes of corneal perforation (n=31 were divided into infectious (n=8, 26% and noninfectious (n=23, 74% categories. Infectious causes included fungal ulcer, herpetic stromal necrotizing keratitis, and bacterial ulcer. The causes of noninfectious keratopathy included corneal melting after removal of a metal foreign body, severe dry eye, lagophthalmos, canaliculitis, the oral anticancer drug S-1, keratoconus, rheumatoid arthritis, neurotrophic ulcer, atopic keratoconjunctivitis, and unknown causes. Initial surgical procedures included central large corneal graft (n=17, small corneal graft (n=7, and amniotic membrane transplantation (n=7. In two cases the perforation could not be sealed during the first surgical treatment and required subsequent procedures. All infectious keratitis required central large penetrating keratoplasty to obtain anatomical cure. In contrast, several surgical options were used for the treatment of noninfectious keratitis. After surgical treatment, anatomical cure was obtained in all cases. Mean postoperative best corrected visual acuity was better at 6 months (logMAR 1.3 than preoperatively (logMAR 1.8.Conclusion: Surgical therapies for corneal perforations in our hospital included central large lamellar/penetrating keratoplasty, small peripheral patch graft, and amniotic membrane transplantation. All treatments were effective. Corneal

  11. Reliability of corneal dynamic scheimpflug analyser measurements in virgin and post-PRK eyes.

    Chen, Xiangjun; Stojanovic, Aleksandar; Hua, Yanjun; Eidet, Jon Roger; Hu, Di; Wang, Jingting; Utheim, Tor Paaske

    2014-01-01

    To determine the measurement reliability of CorVis ST, a dynamic Scheimpflug analyser, in virgin and post-photorefractive keratectomy (PRK) eyes and compare the results between these two groups. Forty virgin eyes and 42 post-PRK eyes underwent CorVis ST measurements performed by two technicians. Repeatability was evaluated by comparing three consecutive measurements by technician A. Reproducibility was determined by comparing the first measurement by technician A with one performed by technician B. Intraobserver and interobserver intraclass correlation coefficients (ICCs) were calculated. Univariate analysis of covariance (ANCOVA) was used to compare measured parameters between virgin and post-PRK eyes. The intraocular pressure (IOP), central corneal thickness (CCT) and 1st applanation time demonstrated good intraobserver repeatability and interobserver reproducibility (ICC ≧ 0.90) in virgin and post-PRK eyes. The deformation amplitude showed a good or close to good repeatability and reproducibility in both groups (ICC ≧ 0.88). The CCT correlated positively with 1st applanation time (r = 0.437 and 0.483, respectively, pPRK eyes, virgin eyes showed longer 1st applanation time (7.29 ± 0.21 vs. 6.96 ± 0.17 ms, pPRK eyes. There were differences in 1st applanation time and deformation amplitude between virgin and post-PRK eyes, which may reflect corneal biomechanical changes occurring after the surgery in the latter.

  12. Corneal markers of diabetic neuropathy.

    Pritchard, Nicola; Edwards, Katie; Shahidi, Ayda M; Sampson, Geoff P; Russell, Anthony W; Malik, Rayaz A; Efron, Nathan

    2011-01-01

    Diabetic neuropathy is a significant clinical problem that currently has no effective therapy, and in advanced cases, leads to foot ulceration and lower limb amputation. The accurate detection, characterization and quantification of this condition are important in order to define at-risk patients, anticipate deterioration, monitor progression, and assess new therapies. This review evaluates novel corneal methods of assessing diabetic neuropathy. Two new noninvasive corneal markers have emerged, and in cross-sectional studies have demonstrated their ability to stratify the severity of this disease. Corneal confocal microscopy allows quantification of corneal nerve parameters and noncontact corneal esthesiometry, the functional correlate of corneal structure, assesses the sensitivity of the cornea. Both these techniques are quick to perform, produce little or no discomfort for the patient, and are suitable for clinical settings. Each has advantages and disadvantages over traditional techniques for assessing diabetic neuropathy. Application of these new corneal markers for longitudinal evaluation of diabetic neuropathy has the potential to reduce dependence on more invasive, costly, and time-consuming assessments, such as skin biopsy.

  13. The ocular biometric and corneal topographic characteristics of high-anisometropic adults in Taiwan

    Ni-Wen Kuo

    2011-07-01

    Conclusion: The anterior chamber depth is deeper, axial length is longer, and thinnest corneal thickness is thicker in the more myopic/less hyperopic eye of high-anisometropic patients. Anisometropic eyes provide the chance to understand the biometric changes of eyeball with different refractive statuses in the same person. Such information is helpful for us to calculate the intraocular lenses power in cataract surgery and to do the surgical planning for corneal refractive surgery in eyes of different refractive power.

  14. Kinetics of corneal epithelium turnover in vivo. Studies of lovastatin

    Cenedella, R.J.; Fleschner, C.R.

    1990-01-01

    The authors developed a direct chemical approach for estimating the rate of turnover of the corneal epithelium in vivo. The method was used to examine the effects of lovastatin, a potent inhibitor of cholesterol biosynthesis, on proliferation and turnover of the epithelium. Corneal DNA was labeled by pulse injection (IP) of the rat with 3H-thymidine, and 3H-labeled DNA was recovered from peripheral and central corneas over the next 15 days. Only the epithelium became labeled, and the loss of label by cell desquamation began 3 days after injection. The loss of 3H-DNA from the cornea (peripheral plus central region) followed first-order kinetics. The half-life of the disappearance was about 3 days. The peripheral cornea became more highly labeled than the central cornea and began to lose 3H-DNA before the central cornea. These observations support the possibility of a higher mitotic rate in the peripheral region and the centripetal movement of a population of peripheral epithelial cells in the normal cornea. The half-lives of the disappearance of 3H-DNA from peripheral and central corneas measured between days 5 and 15 postinjection were identical, both at 3 days. Complete turnover of the corneal epithelium would, therefore, require about 2 weeks (4-5 half-lives). Treatment of the rat with lovastatin had no obvious effects upon the proliferation or turnover of the corneal epithelium. Although lovastatin inhibited corneal 3-hydroxy-3-methylglutaryl coenzyme A reductase, the key regulatory enzyme of cholesterol synthesis, the cornea compensated by induction of this enzyme so that there was no net inhibition of cholesterol synthesis in the cornea

  15. Transepithelial Riboflavin Absorption in an Ex Vivo Rabbit Corneal Model.

    Gore, Daniel M; O'Brart, David; French, Paul; Dunsby, Chris; Allan, Bruce D

    2015-07-01

    To measure depth-specific riboflavin concentrations in corneal stroma using two-photon fluorescence microscopy and compare commercially available transepithelial corneal collagen cross-linking (CXL) protocols. Transepithelial CXL riboflavin preparations--MedioCross TE, Ribocross TE, Paracel plus VibeX Xtra, and iontophoresis with Ricrolin+--were applied to the corneal surface of fresh postmortem rabbit eyes in accordance with manufacturers' recommendations for clinical use. Riboflavin 0.1% (VibeX Rapid) was applied after corneal epithelial debridement as a positive control. After riboflavin application, eyes were snap frozen in liquid nitrogen. Corneal cross sections 35-μm thick were cut on a cryostat, mounted on a slide, and imaged by two-photon fluorescence microscopy. Mean (SD) concentrations were calculated from five globes tested for each protocol. Peak riboflavin concentration of 0.09% (± 0.01) was observed within the most superficial stroma (stromal depth 0-10 μm) in positive controls (epithelium-off). At the same depth, peak stromal riboflavin concentrations for MedioCross TE, Ricrolin+, Paracel/Xtra, and Ribocross TE were 0.054% (± 0.01), 0.031% (0.003), 0.021% (± 0.001), and 0.015% (± 0.004), respectively. At a depth of 300 μm (within the demarcation zone commonly seen after corneal cross-linking), the stromal concentration in epithelium-off positive controls was 0.075% (± 0.006), while at the same depth MedioCross TE and Ricrolin+ achieved 0.018% (± 0.006) and 0.016% (0.002), respectively. None of the remaining transepithelial protocols achieved concentrations above 0.005% at this same 300-μm depth. Overall, MedioCross TE was the best-performing transepithelial formulation. Corneal epithelium is a significant barrier to riboflavin absorption into the stroma. Existing commercial transepithelial CXL protocols achieve relatively low riboflavin concentrations in the anterior corneal stroma when compared to gold standard epithelium-off absorption

  16. Mapping distribution and thickness of supraglacial debris in the Central Karakoram National Park: main features and implications to model glacier meltwater

    Minora, Umberto; Mayer, Christoph; Bocchiola, Daniele; D'Agata, Carlo; Maragno, Davide; Lambrecht, Astrid; Vuillermoz, Elisa; smiraglia, claudio; diolaiuti, guglielmina

    2014-05-01

    Supraglacial debris plays a not negligible role in controlling magnitude and rates of buried ice melt (Østrem, 1959; Mattson et al., 1993). Knowledge on rock debris is essential to model ice melt (and consequently meltwater discharge) upon wide glacierized areas, as melt rates are mainly driven by debris thickness variability. This is particularly important for the Pamir-Himalaya-Karakoram area (PHK), where debris-covered glaciers are frequent (Smiraglia et al., 2007; Scherler et al., 2011) and where melt water from glaciers supports agriculture and hydropower production. By means of remote sensing techniques and field data, supraglacial debris can be detected, and then quantified in area and thickness. Supervised classifications of satellite imagery can be used to map debris on glaciers. They use different algorithms to cluster an image based on its pixel values, and Region Of Interests (ROIs) previously selected by the human operator. This can be used to obtain a supraglacial debris mask by which surface extension can be calculated. Moreover, kinetic surface temperature data derived from satellites (such as ASTER and Landsat), can be used to quantify debris thicknesses (Mihalcea et al., 2008). Ground Control Points (GCPs) are essential to validate the obtained debris thicknesses. We took the Central Karakoram National Park (CKNP) as a representative sample for PHK area. The CKNP is 12,000 km2 wide, with more than 700 glaciers, mostly debris covered (Minora et al., 2013). Among those we find some of the widest glaciers of the World (e.g: Baltoro). To improve the knowledge on these glaciers and to better model their melt and water discharge we proceeded as follows. Firstly we ran a Supervised Maximum Likelihood (SML) classification on 2001 and 2010 Landsat images to detect debris presence and distribution. Secondly we analyzed kinetic surface temperature (from Landsat) to map debris depth. This latter attempt took also advantage from field data of debris thickness

  17. A Rare Form of Corneal Opacity Associated with Spondyloepiphyseal Dysplasia Congenita

    Yuichiro Ishida

    2018-02-01

    Full Text Available A 13-year-old Japanese female diagnosed with spondyloepiphyseal dysplasia congenita (SEDC was referred for ophthalmologic evaluation. Examination with slit-lamp and optical coherence tomography revealed bilateral thin cornea with diffuse corneal opacity which was localised at the posterior stromal depth in the central cornea. Unlike the two previously reported cases of diffuse and nodular patterns of corneal opacity in SEDC, the current case exhibited a rare form of corneal opacity. SEDC is one of the type II collagenopathies, characterised by dwarfism because the mutations in COL2A1 prevent bone growth. Although the existence of type II collagen has not been reported in the human corneal stroma, the aetiology of the opacity in the corneal stroma in SEDC type II collagenopathy is of interest.

  18. Femtosecond laser-assisted keratoplasty in a child with corneal opacity:case report

    E. Yu. Markova

    2014-01-01

    Full Text Available Corneal opacities are the fourth cause of blindness world-wide. Over the past two centuries, various corneal transplantation (i.e., keratoplasty methods have been developed and improved. Nowadays, femtolaserssisted keratoplasty is one of most promising techniques. Femtosecond laser have several advantages that provide additional surgical benefits. Among them, no thermal injury, the ability to cut deeply on a single plane and to perform various corneal profiles should be mentioned. In children, corneal disorders are of special importance while femtosecondassisted keraatoplasty case reports are rare. Here, we describe femtosecond laserssisted penetrating keratoplasty in a girl with a rough central corneal opacity.

  19. Fusarium dimerum Species Complex (Fusarium penzigii) Keratitis After Corneal Trauma.

    do Carmo, Anália; Costa, Esmeralda; Marques, Marco; Quadrado, Maria João; Tomé, Rui

    2016-12-01

    We report a case of a keratitis associated with a Fusarium penzigii-a Fusarium dimerum species complex (FDSC)-in a 81-year-old woman after a corneal trauma with a tree branch. At patient admittance, slit lamp biomicroscopy revealed an exuberant chemosis, an inferior corneal ulcer with an associated inflammatory infiltrate, a central corneal abscess, bullous keratopathy and posterior synechiae. Corneal scrapes were obtained for identification of bacteria and fungi, and the patient started antibiotic treatment on empirical basis. Few days later, the situation worsened with the development of hypopyon. By that time, Fusarium was identified in cultures obtained from corneal scrapes and the patient started topical amphotericin B 0.15 %. Upon the morphological identification of the Fusarium as a FDSC, and since there was no clinical improvement, the treatment with amphotericin B was suspended and the patient started voriconazole 10 mg/ml, eye drops, hourly and voriconazole 200 mg iv, every 12 h for 1 month. The hypopyon resolved and the inflammatory infiltrate improved, but the abscess persisted at the last follow-up visit. The molecular identification revealed that the FDSC was a F. penzigii.

  20. Treatment of Corneal Neovascularization Using Anti-VEGF Bevacizumab

    Deli Krizova

    2014-01-01

    Full Text Available Purpose. To evaluate antiangiogenic effect of local use of bevacizumab (anti-VEGF antibody in patients with corneal neovascularization. Methods. Patients were divided into two groups. All patients suffered from some form of corneal neovascularization (NV. Patients in group A received 0.2–0.5 mL of bevacizumab solution subconjunctivally (concentration 25 mg/mL in a single dose. Group A included 28 eyes from 27. Patients in group B applied bevacizumab eye drops twice daily (concentration 2.5 mg/mL for two weeks. Group B included 38 eyes from 35 patients. We evaluated the number of corneal segments affected by NV, CDVA, and the incidence of complications and subjective complaints related to the treatment. The minimum follow-up period was six months. Results. By the 6-month follow-up, in group A the percentage reduction of the affected peripheral segments was 21.6% and of the central segments was 9.6%; in group B the percentage reduction of the central segments was 22.7% and of the central segments was 38.04%. In both groups we noticed a statistically significant reduction in the extent of NV. Conclusion. The use of bevacizumab seems to be an effective and safe method in the treatment of corneal neovascularization, either in the subconjunctival or topical application form.

  1. Corneal Toxicity Following Exposure to Asclepias Tuberosa.

    Mikkelsen, Lauge Hjorth; Hamoudi, Hassan; Gül, Cigdem Altuntas; Heegaard, Steffen

    2017-01-01

    To present a case of corneal toxicity following exposure to milky plant latex from Asclepias tuberosa. A 70-year-old female presented with blurred vision and pain in her left eye after handling an Ascepias tuberosa . Clinical examination revealed a corneal stromal oedema with small epithelial defects. The corneal endothelium was intact and folds in Descemets membrane were observed. The oedema was treated with chloramphenicol, dexamethasone and scopolamine. The corneal oedema had appeared after corneal exposure to the plant, Asclepias tuberosa , whose latex contains cardenolides that inhibit the Na + / K + -ATPase in the corneal endothelium. The oedema resolved after 96 hours. After nine months the best corrected visual acuity was 20/20. Corneal toxicity has previously been reported for plants of the Asclepias family. This is a rare case describing severe corneal toxicity caused by exposure to latex from Asclepias tuberosa . Handling of plants of the Asclepias family should be kept as a differential diagnosis in cases of acute corneal toxicity.

  2. Ocular forward light scattering and corneal backward light scattering in patients with dry eye.

    Koh, Shizuka; Maeda, Naoyuki; Ikeda, Chikako; Asonuma, Sanae; Mitamura, Hayato; Oie, Yoshinori; Soma, Takeshi; Tsujikawa, Motokazu; Kawasaki, Satoshi; Nishida, Kohji

    2014-09-18

    To evaluate ocular forward light scattering and corneal backward light scattering in patients with dry eye. Thirty-five eyes in 35 patients with dry eye and 20 eyes of 20 healthy control subjects were enrolled. The 35 dry eyes were classified into two groups according to whether superficial punctate keratopathy in the central 6-mm corneal zone (cSPK) was present or not. Ocular forward light scattering was quantified with a straylight meter. Corneal backward light scattering from the anterior, middle, and posterior corneal parts was assessed with a corneal densitometry program using the Scheimpflug imaging system. Both dry eye groups had significantly higher intraocular forward light scattering than the control group (both Pdry eye group with cSPK had significantly higher values in anterior and total corneal backward light scattering than the other two groups. Moderate positive correlations were observed between the cSPK score and corneal backward light scattering from the anterior cornea (R=0.60, Pdry eyes than in normal eyes. Increased corneal backward light scattering in dry eye at least partially results from cSPK overlying the optical zone. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  3. Changes in the micromorphology of the corneal subbasal nerve plexus in patients after plaque brachytherapy

    Zhivov, Andrey; Winter, Karsten; Peschel, Sabine; Stachs, Oliver; Wree, Andreas; Hildebrandt, Guido; Guthoff, Rudolf

    2013-01-01

    To quantify the development of radiation neuropathy in corneal subbasal nerve plexus (SNP) after plaque brachytherapy, and the subsequent regeneration of SNP micromorphology and corneal sensation. Nine eyes of 9 melanoma patients (ciliary body: 3, iris: 2, conjunctiva: 4) underwent brachytherapy (ruthenium-106 plaque, dose to tumour base: 523 ± 231 Gy). SNP micromorphology was assessed by in-vivo confocal microscopy. Using software developed in–house, pre-irradiation findings were compared with those obtained after 3 days, 1, 4 and 7 months, and related to radiation dose and corneal sensation. After 3 days nerve fibres were absent from the applicator zone and central cornea, and corneal sensation was abolished. The earliest regenerating fibres were seen at the one-month follow-up. By 4 months SNP structures had increased to one-third of pre-treatment status (based on nerve fibre density and nerve fibre count), and corneal sensation had returned to approximately two-thirds of pre-irradiation values. Regeneration of SNP and corneal sensation was nearly complete 7 months after plaque brachytherapy. The evaluation of SNP micromorphology and corneal sensation is a reliable and clinically useful method for assessing neuropathy after plaque brachytherapy. Radiation-induced neuropathy of corneal nerves develops quickly and is partly reversible within 7 months. The clinical impact of radiation-induced SNP damage is moderate

  4. Cornea stress test--evaluation of corneal endothelial function in vivo by contact lens induced stress

    Saini Jagjit

    1997-01-01

    Full Text Available Reliable and valid assessment of corneal endothelial function is a critical input for diagnosing, prognosticating and monitoring progression of disorders affecting corneal endothelium. In 123 eyes, corneal endothelial function was assessed employing data from the corneal hydration recovery dynamics. Serial pachometric readings were recorded on Haag-Striet pachometer with Mishima-Hedbys modification before and after two hours of thick soft contact lens wear. Percentage Recovery Per Hour (PRPH was derived from raw data as an index of endothelial function. Assessed PRPH in pseudophakic corneal oedema and Fuchs′ endothelial dystrophy eyes (35.9 +/- 9.8% was significantly lower than normal controls (61.9 +/- 10.5%. On employing receiver operation characteristics curve analysis the tested results demonstrated high sensitivity (87% and specificity (92% for detection of low endothelial function at PRPH cut off of 47.5%. Using this PRPH cut off, 80% of Fuchs′ endothelial dystrophy and 93.3% of pseudophakic corneal oedema eyes could be demonstrated to have low endothelial function. A total of 66.7% of diabetic eyes also demonstrated PRPH of lower than 47.5%. Clear corneal grafts demonstrated PRPH values of 24.6% to 73.0%. Of 6 corneal grafts that demonstrated initial PRPH of lower than 47.5%, 4 failed within 4 to 6 months. Our data demonstrated high sensitivity and specificity of this corneal stress test. PRPH index was useful in quantifying endothelial function in clinical disorders including diabetes mellitus. The index PRPH was demonstrated to be useful in monitoring and prognosticating outcome of corneal grafts.

  5. CONTACT LENS RELATED CORNEAL ULCER

    AGARWAL P

    2010-01-01

    Full Text Available A corneal ulcer caused by infection is one of the major causes of blindness worldwide. One of the recent health concerns is the increasing incidence of corneal ulcers associated with contact lens user especially if the users fail to follow specific instruction in using their contact lenses. Risk factors associated with increased risk of contact lens related corneal ulcers are:overnight wear, long duration of continuous wear, lower socio-economic classes, smoking, dry eye and poor hygiene. The presenting symptoms of contact lens related corneal ulcers include eye discomfort, foreign body sensation and lacrimation. More serious symptoms are redness (especially circum-corneal injection, severe pain, photophobia, eye discharge and blurring of vision. The diagnosis is established by a thorough slit lamp microscopic examination with fluorescein staining and corneal scraping for Gram stain and culture of the infective organism. Delay in diagnosing and treatment can cause permanent blindness, therefore an early referral to ophthalmologist and commencing of antimicrobial therapy can prevent visual loss.

  6. [Corneal transparency: anatomical basis and evaluation methods].

    Avetisov, S E; Narbut, M N

    Being just a relatively small part of the fibrous tunic of the eyeball, the cornea is, nevertheless, unique in terms of the variety of its functions. Because the cornea differs significantly from other protective frames in its structure, it provides the possibility of light transmission and strong refraction that largely contributes to the total refraction of the eye. The development of ophthalmology is impossible without improving methods of adequate anatomical and functional assessment of the eye not only as a whole, but also as a collection of interacting structures.In this regard, examination methods of the cornea have undergone significant advances in recent years. So far, the level of corneal transparency has been judged by biomicroscopy findings or indirect characteristics (thickness, structure, etc.). Confocal microscopy of the cornea and wave-based examinations involving one of the available laser interferometers (OCT or HRT) are also used. However, the data obtained with these methods resembles that of layer-specific reflectometry, i.e. the magnitude of directed reflection of the light beam from corneal corpuscles, which does not completely agree with the classical idea of transparency.

  7. Evaluation of the cytotoxic effects of ophthalmic solutions containing benzalkonium chloride on corneal epithelium using an organotypic 3-D model.

    Khoh-Reiter, Su; Jessen, Bart A

    2009-07-28

    Benzalkonium chloride (BAC) is a common preservative used in ophthalmic solutions. The aim of this study was to compare the cytotoxic effects of BAC-containing ophthalmic solutions with a BAC-free ophthalmic solution using an organotypic 3-dimensional (3-D) corneal epithelial model and to determine the effects of latanoprost ophthalmic solution and its BAC-containing vehicle on corneal thickness in a monkey model. The cytotoxicity of commercially available BAC-containing ophthalmic formulations of latanoprost (0.02% BAC) and olopatadine (0.01% BAC) was compared to that of BAC-free travoprost and saline in a corneal organotypic 3-D model using incubation times of 10 and 25 minutes. To compare the extent of differentiation of 3-D corneal cultures to monolayer transformed human corneal epithelial (HCE-T) cell cultures, expression levels (mRNA and protein) of the corneal markers epidermal growth factor receptor, transglutaminase 1 and involucrin were quantified. Finally, latanoprost ophthalmic solution or its vehicle was administered at suprapharmacologic doses (two 30 microL drops twice daily in 1 eye for 1 year) in monkey eyes, and corneal pachymetry was performed at baseline and at weeks 4, 13, 26 and 52. In the 3-D corneal epithelial culture assays, there were no significant differences in cytotoxicity between the BAC-containing latanoprost and olopatadine ophthalmic solutions and BAC-free travoprost ophthalmic solution at either the 10- or 25-minute time points. The 3-D cultures expressed higher levels of corneal epithelial markers than the HCE-T monolayers, indicating a greater degree of differentiation. There were no significant differences between the corneal thickness of monkey eyes treated with latanoprost ophthalmic solution or its vehicle (both containing 0.02% BAC) and untreated eyes. The lack of cytotoxicity demonstrated in 3-D corneal cultures and in monkey studies suggests that the levels of BAC contained in ophthalmic solutions are not likely to cause

  8. Image-guided modified deep anterior lamellar keratoplasty (DALK) corneal transplant using intraoperative optical coherence tomography

    Tao, Yuankai K.; LaBarbera, Michael; Ehlers, Justis P.; Srivastava, Sunil K.; Dupps, William J.

    2015-03-01

    Deep anterior lamellar keratoplasty (DALK) is an alternative to full-thickness corneal transplant and has advantages including the absence of allograft rejection; shortened duration of topical corticosteroid treatment and reduced associated risk of glaucoma, cataract, or infection; and enables use of grafts with poor endothelial quality. DALK begins by performing a trephination of approximately 80% stromal thickness, as measured by pachymetry. After removal of the anterior stoma, a needle is inserted into the residual stroma to inject air or viscoelastic to dissect Descemet's membrane. These procedures are inherently difficult and intraoperative rates of Descemet's membrane perforation between 4-39% have been reported. Optical coherence tomography (OCT) provides high-resolution images of tissue microstructures in the cornea, including Descemet's membrane, and allows quantitation of corneal layer thicknesses. Here, we use crosssectional intraoperative OCT (iOCT) measurements of corneal thickness during surgery and a novel micrometeradjustable biopsy punch to precision-cut the stroma down to Descemet's membrane. Our prototype cutting tool allows us to establish a dissection plane at the corneal endothelium interface, mitigates variability in cut-depths as a result of tremor, reduces procedure complexity, and reduces complication rates. iOCT-guided modified DALK procedures were performed on 47 cadaveric porcine eyes by non-experts and achieved a perforation rate of ~5% with a mean corneal dissection time care.

  9. In situ ultrahigh-resolution optical coherence tomography characterization of eye bank corneal tissue processed for lamellar keratoplasty.

    Brown, Jamin S; Wang, Danling; Li, Xiaoli; Baluyot, Florence; Iliakis, Bernie; Lindquist, Thomas D; Shirakawa, Rika; Shen, Tueng T; Li, Xingde

    2008-08-01

    To use optical coherence tomography (OCT) as a noninvasive tool to perform in situ characterization of eye bank corneal tissue processed for lamellar keratoplasty. A custom-built ultrahigh-resolution OCT (UHR-OCT) was used to characterize donor corneal tissue that had been processed for lamellar keratoplasty. Twenty-seven donor corneas were analyzed. Four donor corneas were used as controls, whereas the rest were processed into donor corneal buttons for lamellar transplantation by using hand dissection, a microkeratome, or a femtosecond laser. UHR-OCT was also used to noninvasively characterize and monitor the viable corneal tissue immersed in storage medium over 3 weeks. The UHR-OCT captured high-resolution images of the donor corneal tissue in situ. This noninvasive technique showed the changes in donor corneal tissue morphology with time while in storage medium. The characteristics of the lamellar corneal tissue with each processing modality were clearly visible by UHR-OCT. The in situ characterization of the femtosecond laser-cut corneal tissue was noted to have more interface debris than shown by routine histology. The effects of the femtosecond laser microcavitation bubbles on the corneal tissue were well visualized at the edges of the lamellar flap while in storage medium. The results of our feasibility study show that UHR-OCT can provide superb, in situ microstructural characterization of eye bank corneal tissue noninvasively. The UHR-OCT interface findings and corneal endothelial disc thickness uniformity analysis are valuable information that may be used to optimize the modalities and parameters for lamellar tissue processing. The UHR-OCT is a powerful approach that will allow us to further evaluate the tissue response to different processing techniques for posterior lamellar keratoplasty. It may also provide information that can be used to correlate with postoperative clinical outcomes. UHR-OCT has the potential to become a routine part of tissue

  10. Cell therapy of congenital corneal diseases with umbilical mesenchymal stem cells: lumican null mice.

    Hongshan Liu

    Full Text Available BACKGROUND: Keratoplasty is the most effective treatment for corneal blindness, but suboptimal medical conditions and lack of qualified medical personnel and donated cornea often prevent the performance of corneal transplantation in developing countries. Our study aims to develop alternative treatment regimens for congenital corneal diseases of genetic mutation. METHODOLOGY/PRINCIPAL FINDINGS: Human mesenchymal stem cells isolated from neonatal umbilical cords were transplanted to treat thin and cloudy corneas of lumican null mice. Transplantation of umbilical mesenchymal stem cells significantly improved corneal transparency and increased stromal thickness of lumican null mice, but human umbilical hematopoietic stem cells failed to do the same. Further studies revealed that collagen lamellae were re-organized in corneal stroma of lumican null mice after mesenchymal stem cell transplantation. Transplanted umbilical mesenchymal stem cells survived in the mouse corneal stroma for more than 3 months with little or no graft rejection. In addition, these cells assumed a keratocyte phenotype, e.g., dendritic morphology, quiescence, expression of keratocyte unique keratan sulfated keratocan and lumican, and CD34. Moreover, umbilical mesenchymal stem cell transplantation improved host keratocyte functions, which was verified by enhanced expression of keratocan and aldehyde dehydrogenase class 3A1 in lumican null mice. CONCLUSIONS/SIGNIFICANCE: Umbilical mesenchymal stem cell transplantation is a promising treatment for congenital corneal diseases involving keratocyte dysfunction. Unlike donated corneas, umbilical mesenchymal stem cells are easily isolated, expanded, stored, and can be quickly recovered from liquid nitrogen when a patient is in urgent need.

  11. Investigation of Overrun-Processed Porous Hyaluronic Acid Carriers in Corneal Endothelial Tissue Engineering.

    Jui-Yang Lai

    Full Text Available Hyaluronic acid (HA is a linear polysaccharide naturally found in the eye and therefore is one of the most promising biomaterials for corneal endothelial regenerative medicine. This study reports, for the first time, the development of overrun-processed porous HA hydrogels for corneal endothelial cell (CEC sheet transplantation and tissue engineering applications. The hydrogel carriers were characterized to examine their structures and functions. Evaluations of carbodiimide cross-linked air-dried and freeze-dried HA samples were conducted simultaneously for comparison. The results indicated that during the fabrication of freeze-dried HA discs, a technique of introducing gas bubbles in the aqueous biopolymer solutions can be used to enlarge pore structure and prevent dense surface skin formation. Among all the groups studied, the overrun-processed porous HA carriers show the greatest biological stability, the highest freezable water content and glucose permeability, and the minimized adverse effects on ionic pump function of rabbit CECs. After transfer and attachment of bioengineered CEC sheets to the overrun-processed HA hydrogel carriers, the therapeutic efficacy of cell/biopolymer constructs was tested using a rabbit model with corneal endothelial dysfunction. Clinical observations including slit-lamp biomicroscopy, specular microscopy, and corneal thickness measurements showed that the construct implants can regenerate corneal endothelium and restore corneal transparency at 4 weeks postoperatively. Our findings suggest that cell sheet transplantation using overrun-processed porous HA hydrogels offers a new way to reconstruct the posterior corneal surface and improve endothelial tissue function.

  12. Comparison of corneal measurements in keratoconic eyes using rotating Scheimpflug camera and scanning-slit topography

    Mohammad Naderan

    2015-04-01

    Full Text Available AIM: To compare the anterior segment measurements obtained by rotating Scheimpflug camera (Pentacam and Scanning-slit topography (Orbscan IIz in keratoconic eyes. METHODS: A total of 121 patients, 71 males (58.7% and 50 females (41.3% (214 eyes with the diagnosis of keratoconus (KC were enrolled in this study. Following diagnosis of KC by slit-lamp biomicroscopic examination, central corneal thickness (CCT, thinnest corneal thickness (TCT, anterior chamber depth (ACD, and pupil diameter (PD were measured by a single examiner using successive instrumentation by Pentacam and Orbscan. RESULTS: There was no significant difference between the two instruments for the measurement of CCT and TCT. In contrast, scanning-slit topography measured ACD (3.46±0.40 mm vs. 3.38±0.33 mm, P=0.019 and PD (4.97±1.26 mm vs 4.08±1.19 mm, P<0.001 significantly larger than rotating Scheimpflug camera. The two devices made similar measurements for CCT (95% CI: -2.94 to 5.06, P=0.602. However, the mean difference for TCT was -6.28 (95% CI: -10.51 to -2.06, P=0.004 showing a thinner measurement by Orbscan than by Pentacam. In terms of the ACD, the mean difference was 0.08 mm (95% CI: 0.04 to 0.12, P<0.001 with Orbscan giving a slightly larger value than Pentacam. Similarly, Orbscan measurement for PD was longer than Pentacam (95% CI: 0.68 to 1.08, P<0.001. CONCLUSION: A good agreement was found between Pentacam and Orbscan concerning CCT measurement while comparing scanning-slit topography and rotating Scheimpflug camera there was an underestimation for TCT and overestimation for ACD and PD.

  13. Corneal Toxicity Following Exposure to Asclepias Tuberosa

    Mikkelsen, Lauge Hjorth; Hamoudi, Hassan; Gül, Cigdem Altuntas

    2017-01-01

    PURPOSE: To present a case of corneal toxicity following exposure to milky plant latex from Asclepias tuberosa. METHODS: A 70-year-old female presented with blurred vision and pain in her left eye after handling an Ascepias tuberosa. Clinical examination revealed a corneal stromal oedema with small...... epithelial defects. The corneal endothelium was intact and folds in Descemets membrane were observed. The oedema was treated with chloramphenicol, dexamethasone and scopolamine. RESULTS: The corneal oedema had appeared after corneal exposure to the plant, Asclepias tuberosa, whose latex contains cardenolides...... that inhibit the Na+/ K+-ATPase in the corneal endothelium. The oedema resolved after 96 hours. After nine months the best corrected visual acuity was 20/20. CONCLUSION: Corneal toxicity has previously been reported for plants of the Asclepias family. This is a rare case describing severe corneal toxicity...

  14. Corneal Toxicity Following Exposure to Asclepias Tuberosa

    Mikkelsen, Lauge Hjorth; Hamoudi, Hassan; G?l, Cigdem Altuntas; Heegaard, Steffen

    2017-01-01

    PURPOSE: To present a case of corneal toxicity following exposure to milky plant latex from Asclepias tuberosa.METHODS: A 70-year-old female presented with blurred vision and pain in her left eye after handling an Ascepias tuberosa. Clinical examination revealed a corneal stromal oedema with small epithelial defects. The corneal endothelium was intact and folds in Descemets membrane were observed. The oedema was treated with chloramphenicol, dexamethasone and scopolamine.RESULTS: The corneal ...

  15. Progress of research on corneal collagen cross-linking for corneal melting

    Ke-Ren Xiao

    2016-06-01

    Full Text Available Corneal collagen cross-linking(CXLcould increase the mechanical strength, biological stability and halt ectasia progression due to covalent bond formed by photochemical reaction between ultraviolet-A and emulsion of riboflavin between collagen fibers in corneal stroma. Corneal melting is an autoimmune related noninfectious corneal ulcer. The mechanism of corneal melting, major treatment, the basic fundamental of ultraviolet-A riboflavin induced CXL and the clinical researches status and experiment in CXL were summarized in the study.

  16. Bilateral Keratectasia 34 Years after Corneal Transplant

    Xavier Valldeperas

    2010-07-01

    Full Text Available We report the clinical findings of a patient with severe bilateral keratectasia 34 years after a penetrating keratoplasty (PK in both eyes. An otherwise healthy 67-year-old man complained of deterioration of the eyesight in both eyes over the last 6 months. The patient was diagnosed with bilateral keratoconus at the age of 32 years, and he underwent a bilateral PK. At presentation, visual acuity was 20/200 in the right eye and light perception in the left eye. A Pentacam pachymetric map revealed a central pachymetry of 720 µm in the right eye and of 710 µm in the left eye, as well as an average paracentral pachymetry of 436 and 270 µm in the 9-mm zone in the right and the left eye, respectively. Corneal topography revealed bilateral irregular and asymmetric bowing with generalized steepening and high corneal power. We describe a case of bilateral keratectasia 34 years after PK in a patient who was originally diagnosed with bilateral keratoconus.

  17. Topical Drug Formulations for Prolonged Corneal Anesthesia

    Wang, Liqiang; Shankarappa, Sahadev A.; Tong, Rong; Ciolino, Joseph B.; Tsui, Jonathan H.; Chiang, Homer H.; Kohane, Daniel S.

    2013-01-01

    Purpose Ocular local anesthetics (OLA’s) currently used in routine clinical practice for corneal anesthesia are short acting and their ability to delay corneal healing makes them unsuitable for long-term use. In this study, we examined the effect on the duration of corneal anesthesia of the site-1 sodium channel blocker tetrodotoxin (TTX), applied with either proparacaine or the chemical permeation enhancer OTAB. The effect of test solutions on corneal healing was also studied. Methods Solutions of TTX, proparacaine, and OTAB, singly or in combination were applied topically to the rat cornea. The blink response, an indirect measure of corneal sensitivity, was recorded using a Cochet-Bonnet esthesiometer, and the duration of corneal anesthesia calculated. The effect of test compounds on the rate of corneal epithelialization was studied in vivo following corneal debridement. Results Combination of TTX and proparacaine resulted in corneal anesthesia that was 8–10 times longer in duration than that from either drug administered alone, while OTAB did not prolong anesthesia. The rate of corneal healing was moderately delayed following co-administration of TTX and proparacaine. Conclusion Co-administration of TTX and proparacaine significantly prolonged corneal anesthesia but in view of delayed corneal re-epithelialization, caution is suggested in use of the combination. PMID:23615270

  18. Comparison of corneal sensation between small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK for myopia.

    Li, Meiyan; Zhou, Zimei; Shen, Yang; Knorz, Michael C; Gong, Lan; Zhou, Xingtao

    2014-02-01

    To compare the impact on corneal sensation after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK (femto-LASIK) in patients with myopia. In this prospective, nonrandomized comparative study, 71 subjects were enrolled. Thirty-eight eyes of 38 patients underwent SMILE and 33 eyes of 33 patients underwent femto-LASIK. Corneal sensation was tested with Cochet-Bonnet esthesiometry in five corneal areas preoperatively and at 1 week and 1, 3, and 6 months postoperatively. Comparison of corneal sensation was performed for the SMILE and femto-LASIK groups. Additionally, the correlations were evaluated between the postoperative corneal sensation, preoperative spherical equivalent, and ablation depth. All tested areas within the cap or flap demonstrated corneal hypoesthesia immediately after both surgeries. SMILE-treated eyes showed less compromised corneal sensation than femto-LASIK-treated eyes at all postoperative visits in the central, inferior, nasal, and temporal areas at the 1-week and 1-month visits. In the SMILE group, the inferior, nasal, and temporal quadrants recovered faster than other areas. In the femto-LASIK group, the sensation over the flap did not recover to preoperative levels by postoperative 6 months. There was no correlation between postoperative corneal sensation, preoperative spherical equivalent, and ablation depth in both groups. The impairment of corneal sensation was less significant in the SMILE group than in the femto-LASIK group and was independent of preoperative spherical equivalent or ablation depth. Copyright 2014, SLACK Incorporated.

  19. Resolution of persistent corneal erosion after administration of topical rebamipide

    Kashima T

    2012-08-01

    Full Text Available Tomoyuki Kashima,1,2 Hideo Akiyama,1 Fumihide Miura,2 Shoji Kishi11Department of Ophthalmology, Gunma University School of Medicine, Maebashi, Japan; 2Department of Ophthalmology, Saku Central Hospital, Saku, JapanAbstract: Rebamipide is an antiulcer agent used to treat gastric ulcer and gastritis. Biological effects of rebamipide include cytoprotection, wound healing, and anti-inflammatory properties that are known to be universal for a variety of tissues in addition to gastrointestinal mucosa. The therapeutic effects of rebamipide eye drops are due to its ability to increase corneal and conjunctival mucin-like substances and improve corneal and conjunctival injury in vivo. In this paper, we report a case of Sjögren's syndrome with complete disappearance of corneal erosion after administration of rebamipide eye drops. This was observed even though corneal erosion had not improved for 6 months after punctal occlusion surgery. The patient was a 33-year-old female, diagnosed with Sjögren's syndrome by a salivary gland biopsy. The corneal and conjunctival surfaces were filled with dense erosions, which did not improve with topical drugs. Punctal plugs were applied several times; however, the plugs were repeatedly shed. All four puncta of both eyelids were surgically occluded, and both corneal and conjunctival erosion was clearly improved. However, the erosion in the inferior cornea of both eyes had not improved for 6 months after surgery. We used the newly approved topical rebamipide for treatment of this patient. The corneal erosion gradually improved and completely disappeared 4 weeks after administration of the drug. Dry eye sensation disappeared at the same time. Both membrane-associated mucin and secreted mucin in the ocular surface are thought to be essential for maintenance of the tear film. Induction of mucin from ocular surface epithelium could be an effective treatment in cases of dry eye caused by mucin deficiency. Through its various

  20. Acute corneal hydrops in keratoconus

    Prafulla K Maharana

    2013-01-01

    Full Text Available Acute corneal hydrops is a condition characterized by stromal edema due to leakage of aqueous through a tear in descemet membrane. The patient presents with sudden onset decrease in vision, photophobia, and pain. Corneal thinning and ectasias combined with trivial trauma to the eye mostly by eye rubbing is considered as the underlying cause. With conservative approach self-resolution takes around 2 to 3 months. Surgical intervention is required in cases of non-resolution of corneal edema to avoid complications and for early visual rehabilitation. Intracameral injection of air or gas such as perflouropropane is the most common surgical procedure done. Recent investigative modality such as anterior segment optical coherence tomography is an extremely useful tool for diagnosis, surgical planning, and postoperative follow up. Resolution of hydrops may improve the contact lens tolerance and visual acuity but most cases require keratoplasty for visual rehabilitation.

  1. Corneal manifestations in systemic diseases

    Zarranz-Ventura, J.; Nova, E. De; Moreno-Montañés, J.

    2008-01-01

    Un gran número de enfermedades sistémicas presentan manifestaciones corneales dentro de su espectro de enfermedad. El estudio detallado de todos los cuadros que asocian patología corneal resulta inabarcable, por ello se presentan las enfermedades más prevalentes o características. Este estudio contempla las enfermedades pulmonares y conectivopatías (colagenosis, enfermedades reumatológicas y enfermedades inflamatorias idiopáticas), las enfermedades dermatológicas, cardiovasculares, hematológi...

  2. [Corneal manifestations in systemic diseases].

    Zarranz Ventura, J; De Nova, E; Moreno-Montañés, J

    2008-01-01

    Systemic diseases affecting the cornea have a wide range of manifestations. The detailed study of all pathologies that cause corneal alteration is unapproachable, so we have centered our interest in the most prevalent or characteristic of them. In this paper we have divided these pathologies in sections to facilitate their study. Pulmonar and conective tissue (like colagen, rheumatologic and idiopathic inflamatory diseases), dermatologic, cardiovascular, hematologic, digestive and hepatopancreatic diseases with corneal alteration are described. Endocrine and metabolic diseases, malnutrition and carential states are also studied, as well as some otorhinolaryngologic and genetic diseases that affect the cornea. Finally, a brief report of ocular toxicity induced by drugs is referred.

  3. Progress in corneal wound healing

    Ljubimov, Alexander V.; Saghizadeh, Mehrnoosh

    2015-01-01

    Corneal wound healing is a complex process involving cell death, migration, proliferation, differentiation, and extracellular matrix remodeling. Many similarities are observed in the healing processes of corneal epithelial, stromal and endothelial cells, as well as cell-specific differences. Corneal epithelial healing largely depends on limbal stem cells and remodeling of the basement membrane. During stromal healing, keratocytes get transformed to motile and contractile myofibroblasts largely due to activation of transforming growth factor-β system. Endothelial cells heal mostly by migration and spreading, with cell proliferation playing a secondary role. In the last decade, many aspects of wound healing process in different parts of the cornea have been elucidated, and some new therapeutic approaches have emerged. The concept of limbal stem cells received rigorous experimental corroboration, with new markers uncovered and new treatment options including gene and microRNA therapy tested in experimental systems. Transplantation of limbal stem cell-enriched cultures for efficient re-epithelialization in stem cell deficiency and corneal injuries has become reality in clinical setting. Mediators and course of events during stromal healing have been detailed, and new treatment regimens including gene (decorin) and stem cell therapy for excessive healing have been designed. This is a very important advance given the popularity of various refractive surgeries entailing stromal wound healing. Successful surgical ways of replacing the diseased endothelium have been clinically tested, and new approaches to accelerate endothelial healing and suppress endothelial-mesenchymal transformation have been proposed including Rho kinase (ROCK) inhibitor eye drops and gene therapy to activate TGF-β inhibitor SMAD7. Promising new technologies with potential for corneal wound healing manipulation including microRNA, induced pluripotent stem cells to generate corneal epithelium, and

  4. Risk assessment for ectasia after corneal refractive surgery.

    Randleman, J Bradley; Woodward, Maria; Lynn, Michael J; Stulting, R Doyle

    2008-01-01

    To analyze the epidemiologic features of ectasia after excimer laser corneal refractive surgery, to identify risk factors for its development, and to devise a screening strategy to minimize its occurrence. Retrospective comparative and case-control study. All cases of ectasia after excimer laser corneal refractive surgery published in the English language with adequate information available through December 2005, unpublished cases seeking treatment at the authors' institution from 1998 through 2005, and a contemporaneous control group who underwent uneventful LASIK and experienced a normal postoperative course. Evaluation of preoperative characteristics, including patient age, gender, spherical equivalent refraction, pachymetry, and topographic patterns; perioperative characteristics, including type of surgery performed, flap thickness, ablation depth, and residual stromal bed (RSB) thickness; and postoperative characteristics including time to onset of ectasia. Development of postoperative corneal ectasia. There were 171 ectasia cases, including 158 published cases and 13 unpublished cases evaluated at the authors' institution. Ectasia occurred after LASIK in 164 cases (95.9%) and after photorefractive keratectomy (PRK) in 7 cases (4.1%). Compared with controls, more ectasia cases had abnormal preoperative topographies (35.7% vs. 0%; Pvs. 40.0 years; Pvs. -5.09 diopters; Pvs. 546.5 microm; Pvs. 317.3 microm; PLASIK that, if validated, represents a significant improvement over current screening strategies.

  5. Interaction of corneal nociceptive stimulation and lacrimal secretion.

    Situ, Ping; Simpson, Trefford L

    2010-11-01

    To investigate the interaction between corneal stimuli at different positions and tear secretion and to establish relationships between nociceptive stimuli detection thresholds and stimulated tearing. Using a computerized Belmonte-esthesiometer, mechanical and chemical stimuli, from 0% to 200% of the threshold in 50% steps, were delivered (in random order) to the central and peripheral (approximately 2-mm inside the limbus) cornea during four separate sessions to 15 subjects. Immediately after each stimulus, tear meniscus height (TMH) was measured using optical coherence tomography to quantify the amount of lacrimal secretion, and subjects reported whether they felt tears starting to accumulate in their eyes. Thresholds (50% detection) for detection of tearing were estimated. TMH increased with increasing stimulus intensity (P lacrimation reflex. Central mechanical corneal stimulation is the most effective stimulus-position pairing and appears to be the major sensory driving force for reflex tear secretion by the lacrimal functional unit.

  6. Correlations between corneal and total wavefront aberrations

    Mrochen, Michael; Jankov, Mirko; Bueeler, Michael; Seiler, Theo

    2002-06-01

    Purpose: Corneal topography data expressed as corneal aberrations are frequently used to report corneal laser surgery results. However, the optical image quality at the retina depends on all optical elements of the eye such as the human lens. Thus, the aim of this study was to investigate the correlations between the corneal and total wavefront aberrations and to discuss the importance of corneal aberrations for representing corneal laser surgery results. Methods: Thirty three eyes of 22 myopic subjects were measured with a corneal topography system and a Tschernig-type wavefront analyzer after the pupils were dilated to at least 6 mm in diameter. All measurements were centered with respect to the line of sight. Corneal and total wavefront aberrations were calculated up to the 6th Zernike order in the same reference plane. Results: Statistically significant correlations (p the corneal and total wavefront aberrations were found for the astigmatism (C3,C5) and all 3rd Zernike order coefficients such as coma (C7,C8). No statistically significant correlations were found for all 4th to 6th order Zernike coefficients except for the 5th order horizontal coma C18 (p equals 0.003). On average, all Zernike coefficients for the corneal aberrations were found to be larger compared to Zernike coefficients for the total wavefront aberrations. Conclusions: Corneal aberrations are only of limited use for representing the optical quality of the human eye after corneal laser surgery. This is due to the lack of correlation between corneal and total wavefront aberrations in most of the higher order aberrations. Besides this, the data present in this study yield towards an aberration balancing between corneal aberrations and the optical elements within the eye that reduces the aberration from the cornea by a certain degree. Consequently, ideal customized ablations have to take both, corneal and total wavefront aberrations, into consideration.

  7. Confocal comparison of corneal reinnervation after small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK).

    Li, Meiyan; Niu, Lingling; Qin, Bing; Zhou, Zimei; Ni, Katherine; Le, Qihua; Xiang, Jun; Wei, Anji; Ma, Weiping; Zhou, Xingtao

    2013-01-01

    To evaluate corneal reinnervation, and the corresponding corneal sensitivity and keratocyte density after small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK). In this prospective, non-randomized observational study, 18 patients (32 eyes) received SMILE surgery, and 22 patients (42 eyes) received FS-LASIK surgery to correct myopia. The corneal subbasal nerve density and microscopic morphological changes in corneal architecture were evaluated by confocal microscopy prior to surgery and at 1 week, 1 month, 3 months, and 6 months after surgery. A correlation analysis was performed between subbasal corneal nerve density and the corresponding keratocyte density and corneal sensitivity. The decrease in subbasal nerve density was less severe in SMILE-treated eyes than in FS-LASIK-treated eyes at 1 week (P = 0.0147), 1 month (P = 0.0243), and 3 months (P = 0.0498), but no difference was detected at the 6-month visit (P = 0.5277). The subbasal nerve density correlated positively with central corneal sensitivity in both groups (r = 0.416, PLASIK group, respectively). The SMILE-treated eyes have a lower risk of developing peripheral empty space with epithelial cells filling in (P = 0.0005). The decrease in subbasal nerve fiber density was less severe in the SMILE group than the FS-LASIK group in the first 3 months following the surgeries. The subbasal nerve density was correlated with central corneal sensitivity.

  8. Removal of the basement membrane enhances corneal wound healing.

    Pal-Ghosh, Sonali; Pajoohesh-Ganji, Ahdeah; Tadvalkar, Gauri; Stepp, Mary Ann

    2011-12-01

    Recurrent corneal erosions are painful and put patients' vision at risk. Treatment typically begins with debridement of the area around the erosion site followed by more aggressive treatments. An in vivo mouse model has been developed that reproducibly induces recurrent epithelial erosions in wild-type mice spontaneously within two weeks after a single 1.5 mm corneal debridement wound created using a dulled-blade. This study was conducted to determine whether 1) inhibiting MMP9 function during healing after dulled-blade wounding impacts erosion development and 2) wounds made with a rotating-burr heal without erosions. Oral or topical inhibition of MMPs after dulled-blade wounding does not improve healing. Wounds made by rotating-burr heal with significantly fewer erosions than dulled-blade wounds. The localization of MMP9, β4 integrin and basement membrane proteins (LN332 and type VII collagen), immune cell influx, and reinnervation of the corneal nerves were compared after both wound types. Rotating-burr wounds remove the anterior basement membrane centrally but not at the periphery near the wound margin, induce more apoptosis of corneal stromal cells, and damage more stromal nerve fibers. Despite the fact that rotating-burr wounds do more damage to the cornea, fewer immune cells are recruited and significantly more wounds resolve completely. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Age, sex, and type of medication predict the effect of anti-VEGF treatment on central retinal thickness in wet age-related macular degeneration

    Bek T

    2018-03-01

    Full Text Available Toke Bek, Sidsel Ehlers Klug Department of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark Purpose: Randomized clinical trials studying the effects of VEGF inhibition on wet age-related macular degeneration (wAMD are designed so that the effects of individually varying risk factors on the treatment response are eliminated. The influence of these risk factors can be studied in large data sets from real-life experience.Patients and methods: All 2,255 patients diagnosed with wAMD requiring anti-VEGF treatment in at least one eye over more than 9 years in a defined Danish population with 0.9 million inhabitants were studied. The predictive value of eye laterality, sex, current smoking status, type of anti-VEGF compound, membrane position, membrane type, leakage area, number of injections, number of visits, age, time to follow-up, visual acuity, and central retinal thickness (CRT at baseline on change in CRT after three monthly injections with anti-VEGF compound followed by treatment pro re nata for up to 12 months was assessed.Results: After 12 months, 67 patients had died, 903 had had stable CRT for at least 6 months, and 1,285 patients had not achieved stable CRT. The reduction in CRT was -84.8±118.3 µm, whereas the increase in visual acuity was 2.2±14.7 Early Treatment Diabetic Retinopathy Study letters. The risk factors included contributed to 64% of the variation in CRT reduction. High age and high CRT at baseline predicted high CRT reduction, whereas more injections, treatment with ranibizumab, and male sex predicted a low CRT reduction.Conclusion: Age, sex, and type of anti-VEGF medication can be used to plan treatment and inform patients about the expected response of anti-VEGF treatment in wAMD. Keywords: wet AMD, anti-VEGF treatment, risk factors, real-life experience 

  10. Evaluation of intracameral injection of ranibizumab and bevacizumab on the corneal endothelium by scanning electron microscopy.

    Ari, Seyhmus; Nergiz, Yusuf; Aksit, Ihsan; Sahin, Alparslan; Cingu, Kursat; Caca, Ihsan

    2015-03-01

    To evaluate the effects of intracameral injection of ranibizumab and bevacizumab on the corneal endothelium by scanning electron microscopy (SEM). Twenty-eight female rabbits were randomly divided into four equal groups. Rabbits in groups 1 and 2 underwent intracameral injection of 1 mg/0.1 mL and 0.5 mg/0.05 mL ranibizumab, respectively; group 3 was injected with 1.25 mg/0.05 mL bevacizumab. All three groups were injected with a balanced salt solution (BSS) into the anterior chamber of the left (fellow) eye. None of the rabbits in group 4 underwent an injection. Corneal thickness and intraocular pressure were measured before the injections, on the first day, and in the first month after injection. The rabbits were sacrificed and corneal tissues were excised in the first month after injection. Specular microscopy was used for the corneal endothelial cell count. Endothelial cell density was assessed and comparisons drawn between the groups and the control. Micrographs were recorded for SEM examination. The structure of the corneal endothelial cells, the junctional area of the cell membrane, the distribution of microvillus, and the cell morphology of the eyes that underwent intracameral injection of vascular endothelial growth factor (VEGF), BSS, and the control group were compared. Corneal thickness and intraocular pressure were not significantly different between the groups that underwent anti-VEGF or BSS injection and the control group on the first day and in the first month of injection. The corneal endothelial cell count was significantly diminished in all three groups; predominantly in group 1 and 2 (P<0.05). The SEM examination revealed normal corneal endothelial histology in group 3 and the control group. Eyes in group 1 exhibited indistinctness of corneal endothelial cell borders, microvillus loss in the luminal surface, excessive blebbing, and disintegration of intercellular junctions. In group 2, the cell structure of the corneal endothelium

  11. Effects of hemodialysis on corneal and anterior chamber morphometry and intraocular pressure in patients with end-stage renal disease

    Mehtap Caglayan

    Full Text Available ABSTRACT Purpose: To evaluate the effects of hemodialysis (HD on corneal and anterior chamber morphometry, as well as intraocular pressure (IOP in patients with end-stage renal disease. Methods: Fifty right eyes were examined 30 minutes before and after HD. IOP was measured with a Goldmann applanation tonometer, and Ehlers' formula was used to calculate the corrected IOP values. The central corneal thickness (CCT, corneal volume (CV, keratometric values, anterior chamber depth (ACD, aqueous depth (AQD, anterior chamber volume (ACV, and anterior chamber angle (ACA in the nasal and temporal quadrants were measured with a Sirius anterior segment analysis system. Blood urea nitrogen levels, body mass, and systolic and diastolic arterial pressure were also measured before and after HD. Results: The mean age was 60.80 ± 13.38 (range: 35-80 years. The mean uncorrected and corrected IOP values decreased from 18.06 ± 3.91 and 18.31 ± 4.83 mmHg to 16.94 ± 3.87 and 16.95 ± 4.74 mmHg after HD, respectively (p=0.011 and p=0.003, respectively. The mean CCT decreased from 536.38 ± 24.73 to 533.18 ± 27.25 µm (p=0.002, and the mean CV decreased from 57.52 ± 3.15 to 55.68 ± 3.55 mm³ (p0.05 for all values. There were no significant correlations between the ocular and systemic parameters (p>0.05 for all correlations. Conclusions: Uncorrected IOP, corrected IOP, CCT, and CV values decreased after HD, whereas the anterior chamber morphometry values remained similar between the measurements performed before and after HD.

  12. Corneal Regeneration After Photorefractive Keratectomy: A Review

    Javier Tomás-Juan

    2015-07-01

    Full Text Available Photorefractive keratectomy (PRK remodels corneal stroma to compensate refractive errors. The removal of epithelium and the ablation of stroma provoke the disruption of corneal nerves and a release of several peptides from tears, epithelium, stroma and nerves. A myriad of cytokines, growth factors, and matrix metalloproteases participate in the process of corneal wound healing. Their balance will determine if reepithelization and stromal remodeling are appropriate. The final aim is to achieve corneal transparency for restoring corneal function, and a proper visual quality. Therefore, wound-healing response is critical for a successful refractive surgery. Our goal is to provide an overview into how corneal wounding develops following PRK. We will also review the influence of intraoperative application of mitomycin C, bandage contact lenses, anti-inflammatory and other drugs in preventing corneal haze and post-PRK pain.

  13. History of corneal transplantation in Australia.

    Coster, Douglas J

    2015-04-01

    Corneal transplantation is a triumph of modern ophthalmology. The possibility of corneal transplantation was first raised in 1797 but a century passed before Zirm achieved the first successful penetrating graft in 1905. Gibson reported the first corneal graft in Australia from Brisbane in 1940 and English established the first eye bank there a few years later. Corneal transplantation evolved steadily over the twentieth century. In the second half of the century, developments in microsurgery, including surgical materials such as monofilament nylon and strong topical steroid drops, accounted for improvements in outcomes. In 2013, approximately 1500 corneal transplants were done in Australia. Eye banking has evolved to cope with the rising demands for donor corneas. Australian corneal surgeons collaborated to establish and support the Australian Corneal Graft Registry in 1985. It follows the outcomes of their surgery and has become an important international resource for surgeons seeking further improvement with the procedure. © 2014 Royal Australian and New Zealand College of Ophthalmologists.

  14. Corneal Regeneration After Photorefractive Keratectomy: A Review.

    Tomás-Juan, Javier; Murueta-Goyena Larrañaga, Ane; Hanneken, Ludger

    2015-01-01

    Photorefractive keratectomy (PRK) remodels corneal stroma to compensate refractive errors. The removal of epithelium and the ablation of stroma provoke the disruption of corneal nerves and a release of several peptides from tears, epithelium, stroma and nerves. A myriad of cytokines, growth factors, and matrix metalloproteases participate in the process of corneal wound healing. Their balance will determine if reepithelization and stromal remodeling are appropriate. The final aim is to achieve corneal transparency for restoring corneal function, and a proper visual quality. Therefore, wound-healing response is critical for a successful refractive surgery. Our goal is to provide an overview into how corneal wounding develops following PRK. We will also review the influence of intraoperative application of mitomycin C, bandage contact lenses, anti-inflammatory and other drugs in preventing corneal haze and post-PRK pain. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  15. Corneal collagen crosslinking and pigment dispersion syndrome.

    LaHood, Benjamin R; Moore, Sacha

    2017-03-01

    We describe the case of a keratoconus patient with pigment dispersion syndrome (PDS) who was treated for progressive corneal ectasia with corneal collagen crosslinking (CXL). Pigment dispersion syndrome has been shown to have associated morphologic changes of the corneal endothelium. Corneal CXL has the potential to cause toxicity to the corneal endothelium, and adjacent pigment might increase the likelihood of damage. In this case, the presence of PDS had no detrimental effect on the outcome of treatment, and no complications were observed at 12 months follow-up, indicating that it may be safe to perform corneal CXL in the setting of PDS. This is an important observation as the number of indications for corneal CXL grows. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  16. Corneal stroma microfibrils.

    Hanlon, Samuel D; Behzad, Ali R; Sakai, Lynn Y; Burns, Alan R

    2015-03-01

    Elastic tissue was first described well over a hundred years ago and has since been identified in nearly every part of the body. In this review, we examine elastic tissue in the corneal stroma with some mention of other ocular structures which have been more thoroughly described in the past. True elastic fibers consist of an elastin core surrounded by fibrillin microfibrils. However, the presence of elastin fibers is not a requirement and some elastic tissue is comprised of non-elastin-containing bundles of microfibrils. Fibers containing a higher relative amount of elastin are associated with greater elasticity and those without elastin, with structural support. Recently it has been shown that the microfibrils, not only serve mechanical roles, but are also involved in cell signaling through force transduction and the release of TGF-β. A well characterized example of elastin-free microfibril bundles (EFMBs) is found in the ciliary zonules which suspend the crystalline lens in the eye. Through contraction of the ciliary muscle they exert enough force to reshape the lens and thereby change its focal point. It is believed that the molecules comprising these fibers do not turn-over and yet retain their tensile strength for the life of the animal. The mechanical properties of the cornea (strength, elasticity, resiliency) would suggest that EFMBs are present there as well. However, many authors have reported that, although present during embryonic and early postnatal development, EFMBs are generally not present in adults. Serial-block-face imaging with a scanning electron microscope enabled 3D reconstruction of elements in murine corneas. Among these elements were found fibers that formed an extensive network throughout the cornea. In single sections these fibers appeared as electron dense patches. Transmission electron microscopy provided additional detail of these patches and showed them to be composed of fibrils (∼10 nm diameter). Immunogold evidence clearly

  17. Corneal stroma microfibrils

    Hanlon, Samuel D.

    2015-03-01

    Elastic tissue was first described well over a hundred years ago and has since been identified in nearly every part of the body. In this review, we examine elastic tissue in the corneal stroma with some mention of other ocular structures which have been more thoroughly described in the past. True elastic fibers consist of an elastin core surrounded by fibrillin microfibrils. However, the presence of elastin fibers is not a requirement and some elastic tissue is comprised of non-elastin-containing bundles of microfibrils. Fibers containing a higher relative amount of elastin are associated with greater elasticity and those without elastin, with structural support. Recently it has been shown that the microfibrils, not only serve mechanical roles, but are also involved in cell signaling through force transduction and the release of TGF-β. A well characterized example of elastin-free microfibril bundles (EFMBs) is found in the ciliary zonules which suspend the crystalline lens in the eye. Through contraction of the ciliary muscle they exert enough force to reshape the lens and thereby change its focal point. It is believed that the molecules comprising these fibers do not turn-over and yet retain their tensile strength for the life of the animal. The mechanical properties of the cornea (strength, elasticity, resiliency) would suggest that EFMBs are present there as well. However, many authors have reported that, although present during embryonic and early postnatal development, EFMBs are generally not present in adults. Serial-block-face imaging with a scanning electron microscope enabled 3D reconstruction of elements in murine corneas. Among these elements were found fibers that formed an extensive network throughout the cornea. In single sections these fibers appeared as electron dense patches. Transmission electron microscopy provided additional detail of these patches and showed them to be composed of fibrils (~10nm diameter). Immunogold evidence clearly

  18. Management of corneal bee sting

    Razmjoo H

    2011-12-01

    Full Text Available Hassan Razmjoo1,2, Mohammad-Ali Abtahi1,2,4, Peyman Roomizadeh1,3, Zahra Mohammadi1,2, Seyed-Hossein Abtahi1,3,41Medical School, Isfahan University of Medical Sciences (IUMS; 2Ophthalmology Ward, Feiz Hospital, IUMS; 3Isfahan Medical Students Research Center (IMSRC, IUMS; 4Isfahan Ophthalmology Research Center (IORC, Feiz Hospital, IUMS, Isfahan, IranAbstract: Corneal bee sting is an uncommon environmental eye injury that can result in various ocular complications with an etiology of penetrating, immunologic, and toxic effects of the stinger and its injected venom. In this study we present our experience in the management of a middle-aged male with a right-sided deep corneal bee sting. On arrival, the patient was complaining of severe pain, blurry vision with acuity of 160/200, and tearing, which he had experienced soon after the injury. Firstly, we administered conventional drugs for eye injuries, including topical antibiotic, corticosteroid, and cycloplegic agents. After 2 days, corneal stromal infiltration and edema developed around the site of the sting, and visual acuity decreased to 100/200. These conditions led us to remove the stinger surgically. Within 25 days of follow-up, the corneal infiltration decreased gradually, and visual acuity improved to 180/200. We suggest a two-stage management approach for cases of corneal sting. For the first stage, if the stinger is readily accessible or primary dramatic reactions, including infiltration, especially on the visual axis, exist, manual or surgical removal would be indicated. Otherwise, we recommend conventional treatments for eye injuries. Given this situation, patients should be closely monitored for detection of any worsening. If the condition does not resolve or even deteriorates, for the second stage, surgical removal of the stinger under local or generalized anesthesia is indicated.Keywords: bee sting, stinger, cornea, removal, management, surgery

  19. Corneal topographic changes after 20-gauge pars plana vitrectomy associated with scleral buckling for the treatment of rhegmatogenous retinal detachment

    Alexandre Achille Grandinetti

    2013-04-01

    Full Text Available PURPOSE: To evaluate the changes in corneal topography after 20-gauge pars plana vitrectomy associated with scleral buckling for the repair of rhegmatogenous retinal detachment. METHODS: Twenty-five eyes of 25 patients with rhegmatogenous retinal detachment were included in this study. 20-gauge pars plana vitrectomy associated with scleral buckling was performed in all patients. The corneal topography of each was measured before surgery and one week, one month, and three months after surgery by computer-assisted videokeratoscopy. RESULTS: A statistically significant central corneal steepening (average, 0,9 D , p<0,001 was noted one week after surgery. The total corneal astigmatism had a significant increase in the first postoperative month (p=0,007. All these topographic changes persisted for the first month but returned to preoperative values three months after the surgery. CONCLUSION: Pars plana vitrectomy with scleral buckling was found to induce transient changes in corneal topography.

  20. Turning the tide of corneal blindness

    Matthew S Oliva

    2012-01-01

    Full Text Available Corneal diseases represent the second leading cause of blindness in most developing world countries. Worldwide, major investments in public health infrastructure and primary eye care services have built a strong foundation for preventing future corneal blindness. However, there are an estimated 4.9 million bilaterally corneal blind persons worldwide who could potentially have their sight restored through corneal transplantation. Traditionally, barriers to increased corneal transplantation have been daunting, with limited tissue availability and lack of trained corneal surgeons making widespread keratoplasty services cost prohibitive and logistically unfeasible. The ascendancy of cataract surgical rates and more robust eye care infrastructure of several Asian and African countries now provide a solid base from which to dramatically expand corneal transplantation rates. India emerges as a clear global priority as it has the world′s largest corneal blind population and strong infrastructural readiness to rapidly scale its keratoplasty numbers. Technological modernization of the eye bank infrastructure must follow suit. Two key factors are the development of professional eye bank managers and the establishment of Hospital Cornea Recovery Programs. Recent adaptation of these modern eye banking models in India have led to corresponding high growth rates in the procurement of transplantable tissues, improved utilization rates, operating efficiency realization, and increased financial sustainability. The widespread adaptation of lamellar keratoplasty techniques also holds promise to improve corneal transplant success rates. The global ophthalmic community is now poised to scale up widespread access to corneal transplantation to meet the needs of the millions who are currently blind.

  1. Clinical applications of corneal confocal microscopy

    Mitra Tavakoli

    2008-06-01

    Full Text Available Mitra Tavakoli1, Parwez Hossain2, Rayaz A Malik11Division of Cardiovascular Medicine, University of Manchester and Manchester Royal Infirmary, Manchester, UK; 2University of Southampton, Southampton Eye Unit, Southampton General Hospital, Southampton, UKAbstract: Corneal confocal microscopy is a novel clinical technique for the study of corneal cellular structure. It provides images which are comparable to in-vitro histochemical techniques delineating corneal epithelium, Bowman’s layer, stroma, Descemet’s membrane and the corneal endothelium. Because, corneal confocal microscopy is a non invasive technique for in vivo imaging of the living cornea it has huge clinical potential to investigate numerous corneal diseases. Thus far it has been used in the detection and management of pathologic and infectious conditions, corneal dystrophies and ecstasies, monitoring contact lens induced corneal changes and for pre and post surgical evaluation (PRK, LASIK and LASEK, flap evaluations and Radial Keratotomy, and penetrating keratoplasty. Most recently it has been used as a surrogate for peripheral nerve damage in a variety of peripheral neuropathies and may have potential in acting as a surrogate marker for endothelial abnormalities.Keywords: corneal confocal microscopy, cornea, infective keratitis, corneal dystrophy, neuropathy

  2. Inverse cutting of posterior lamellar corneal grafts by a femtosecond laser

    Hjortdal, Jesper; Nielsen, Esben; Vestergaard, Anders Højslet

    2012-01-01

    (range: 1.400 to 2.000 cells per sq. mm). The grafts were of uniform thickness, but substantial interface haze was present in most grafts. Conclusions: Posterior lamellar corneal grafts can be prepared from the endothelial side using a femto-second laser. All grafts were clear after 6 months...

  3. Penetrating keratoplasty for treatment of corneal abscesses in horses – case report

    Zita Makra

    2013-01-01

    Full Text Available This case report describes the surgical technique and outcome of allograft transplantation to treat full thickness corneal abscesses in three horses. In all three cases penetrating keratoplasty was performed. Each affected eye had an abscess within the corneal stroma. An initial full thickness circular corneal incision was made around the lesion. After excision of the stromal abscess the created defect was replaced with a larger diameter full thickness donor graft and the initial corneal incision was repaired. All of the horses that underwent penetrating keratoplasty procedure healed with a scar at the graft site and remained visual. Penetrating keratoplasty is an effective technique for surgical removal of medically nonresponsive full thickness stromal abscess in horses and results in a visual and cosmetically acceptable globe. The advantages of this technique compared to medical therapy are that there is less scarring, shorter healing times and less damage of the globe because of the concurrent uveitis. To the authors’ knowledge, clinical experience with penetrating keratoplasty in horses has not been reported in Europe so far.

  4. Evaluation of best corrected visual acuity and central macular thickness after intravitreal dexamethasone implant injections in patients with Irvine-Gass syndrome: A retrospective study of six cases.

    Keilani, Chafik; Halalchi, Aziz; Wakpi Djeugue, Désiré; Regis, Anne; Abada, Samir

    2016-10-01

    Irvine-Gass syndrome is a macular edema (ME) that specifically occurs after cataract surgery. Its incidence varies from 0.2-2%. The purpose of this study is to evaluate the effectiveness of intravitreal dexamethasone implant injections in patients with Irvine-Gass syndrome. Patients with ME secondary to cataract surgery who underwent intravitreal injections of dexamethasone implant between December 2011 to October 2014 at François-Quesnay hospital (Mantes-la-Jolie, France) were retrospectively reviewed. The patients were followed for at least 10 months. All the patients were handled by intravitreal injection of dexamethasone in the eye of study among which some resisted to a preliminary treatment by non-steroidal anti-inflammatory drug (NSAID) and acetazolamide. The patients were examined each month. The patients were again handled by intravitreal injection of dexamethasone if they presented a recurrence. The primary endpoint of the study was determined on best corrected visual acuity (BCVA) using early diabetic retinopathy study (ETDRS) scale and central macular thickness (CMT) [μm] using optical coherence tomography (OCT) 3 and 6 months after the first injection. Secondary endpoints were the number of recurrences, the number of injections, the duration average before the first recurrence, the BCVA 10 months after the first injection and the tolerance. Six eyes of six patients were studied. At baseline, the mean (standard deviation [SD]) of the BCVA was 59.8±11. Three months after the first injection, the mean (SD) of the BCVA showed a statistically significant increase to 72.2±8.6 (P=0.03). Six months after the first injection, the mean (SD) of the BCVA showed a statistically significant increase to 72±11.8 (P=0.03). Concerning the CMT, the mean (SD) was 495.6±135.2 before treatment. Three months after the first injection, the mean (SD) of the CMT showed a statistically significant decrease to 268.6±57.8 (P=0.03). Six months after the first injection, the

  5. Thermal and infrared-diode laser effects on indocyanine-green-treated corneal collagen

    Timberlake, George T.; Patmore, Ann; Shallal, Assaad; McHugh, Dominic; Marshall, John

    1993-07-01

    It has been suggested that laser welds of collagenous tissues form by interdigitation and chemical bonding of thermally 'unraveled' collagen fibrils. We investigated this proposal by attempting to weld highly collagenous, avascular corneal tissue with an infrared (IR) diode laser as follows. First, the temperature at which corneal collagen shrinks and collagen fibrils 'split' into subfibrillary components was determined. Second, since use of a near-IR laser wavelength necessitated addition of an absorbing dye (indocyanine green (ICG) to the cornea, we measured absorption spectra of ICG-treated tissue to ensure that peak ICG absorbance did not change markedly when ICG was present in the cornea. Third, using gel electrophoresis of thermally altered corneal collagen, we searched for covalently crosslinked compounds predicted by the proposed welding mechanism. Finally, we attempted to weld partial thickness corneal incisions infused with ICG. Principal experimental findings were as follows: (1) Human corneal (type I) collagen splits into subfibrillary components at approximately 63 degree(s)C, the same temperature that produces collagen shrinkage. (2) Peak ICG absorption does not change significantly in corneal stroma or with laser heating. (3) No evidence was found for the formation of novel compounds or the loss of proteins as a result of tissue heating. All tissue treated with ICG, however, exhibited a novel 244 kD protein band indicating chemical activity between collagen and corneal stromal components. (4) Laser welding corneal incisions was unsuccessful possibly due to shrinkage of the sides of the incision, lack of incision compression during heating, or a less than optimal combination of ICG concentration and radiant exposure. In summary, these experiments demonstrate the biochemical and morphological complexity of ICG-enhanced IR laser-tissue welding and the need for further investigation of laser welding mechanisms.

  6. Reliability of corneal dynamic scheimpflug analyser measurements in virgin and post-PRK eyes.

    Xiangjun Chen

    Full Text Available PURPOSE: To determine the measurement reliability of CorVis ST, a dynamic Scheimpflug analyser, in virgin and post-photorefractive keratectomy (PRK eyes and compare the results between these two groups. METHODS: Forty virgin eyes and 42 post-PRK eyes underwent CorVis ST measurements performed by two technicians. Repeatability was evaluated by comparing three consecutive measurements by technician A. Reproducibility was determined by comparing the first measurement by technician A with one performed by technician B. Intraobserver and interobserver intraclass correlation coefficients (ICCs were calculated. Univariate analysis of covariance (ANCOVA was used to compare measured parameters between virgin and post-PRK eyes. RESULTS: The intraocular pressure (IOP, central corneal thickness (CCT and 1st applanation time demonstrated good intraobserver repeatability and interobserver reproducibility (ICC ≧ 0.90 in virgin and post-PRK eyes. The deformation amplitude showed a good or close to good repeatability and reproducibility in both groups (ICC ≧ 0.88. The CCT correlated positively with 1st applanation time (r = 0.437 and 0.483, respectively, p<0.05 and negatively with deformation amplitude (r = -0.384 and -0.375, respectively, p<0.05 in both groups. Compared to post-PRK eyes, virgin eyes showed longer 1st applanation time (7.29 ± 0.21 vs. 6.96 ± 0.17 ms, p<0.05 and lower deformation amplitude (1.06 ± 0.07 vs. 1.17 ± 0.08 mm, p < 0.05. CONCLUSIONS: CorVis ST demonstrated reliable measurements for CCT, IOP, and 1st applanation time, as well as relatively reliable measurement for deformation amplitude in both virgin and post-PRK eyes. There were differences in 1st applanation time and deformation amplitude between virgin and post-PRK eyes, which may reflect corneal biomechanical changes occurring after the surgery in the latter.

  7. Evaluation of intrastromal corneal ring segments for treatment of keratoconus with a mechanical implantation technique

    Zeki Tunc

    2013-01-01

    Full Text Available Purpose: To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS implantation in patients with keratoconus using a mechanical implantation technique. Materials and Methods: Thirty eyes of 17 patients with keratoconus were enrolled. ICRSs (Keraring were implanted after dissection of the tunnel using Tunc′s specially designed dissector under suction. A complete ophthalmic examination was performed, including uncorrected distance visual acuity (UDVA, corrected distance visual acuity (CDVA, spherical equivalent, keratometric readings, inferosuperior asymmetry index (ISAI, and ultrasound pachymetry. All 3-, 6-, and 12-month follow-ups were completed, and statistical analysis was performed. Results: The mean preoperative UDVA for all eyes was 1.36 ± 0.64 logMAR. At 12 months, the mean UDVA was 0.51 ± 0.28 logMAR (P = 0.001, and the mean preoperative CDVA was 0.57 ± 0.29 logMAR, which improved to 0.23 ± 0.18 (P = 0.001 at 1 year. There was a significant reduction in spherical equivalent refractive error from -6.42 ± 4.69 diopters (D preoperatively to -1.26 ± 1.45 D (P = 0.001 at 1 year. In the same period, the mean K-readings improved from 49.38 ± 3.72 D to 44.43 ± 3.13 D (P = 0.001, and the mean ISAI improved from 7.92 ± 3.12 to 4.21 ± 1.96 (P = 0.003. No significant changes in mean central corneal thickness were observed postoperatively. There were no major complications during and or after surgery. Conclusion: ICRS implantation using a unique mechanical dissection technique is a safe and effective treatment for keratoconus. All parameters improved by the 1-year follow-up.

  8. Changes in corneal endothelial cell density and the cumulative risk of corneal decompensation after Ahmed glaucoma valve implantation.

    Kim, Kyoung Nam; Lee, Sung Bok; Lee, Yeon Hee; Lee, Jong Joo; Lim, Hyung Bin; Kim, Chang-Sik

    2016-07-01

    To evaluate changes in the corneal endothelial cell density (ECD) and corneal decompensation following Ahmed glaucoma valve (AGV) implantation. This study was retrospective and observational case series. Patients with refractory glaucoma who underwent AGV implantation and were followed >5 years were consecutively enrolled. We reviewed the medical records, including the results of central corneal specular microscopy. Of the 127 enrolled patients, the annual change in ECD (%) was determined using linear regression for 72 eyes evaluated at least four times using serial specular microscopic examination and compared with 31 control eyes (fellow glaucomatous eyes under medical treatment). The main outcome measures were cumulative risk of corneal decompensation and differences in the ECD loss rates between subjects and controls. The mean follow-up after AGV implantation was 43.1 months. There were no cases of postoperative tube-corneal touch. The cumulative risk of corneal decompensation was 3.3%, 5 years after AGV implantation. There was a more rapid loss of ECD in the 72 subject eyes compared with the 31 controls (-7.0% and -0.1%/year, respectively; p<0.001). However, the rate of loss decreased over time and statistical significance compared with control eyes disappeared after 2 years postoperatively: -10.7% from baseline to 1 year (p<0.01), -7.0% from 1 year to 2 years (p=0.037), -4.2% from 2 years to 3 years (p=0.230) and -2.7% from 3 years to the final follow-up (p=0.111). In case of uncomplicated AGV implantation, the cumulative risk of corneal decompensation was 3.3%, 5 years after the operation. The ECD loss was statistically greater in eyes with AGV than in control eyes without AGV, but the difference was significant only up to 2 years post surgery. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  9. Visual outcome after corneal transplantation for corneal perforation and iris prolapse in 37 horses

    Henriksen, Michala de Linde; Plummer, C. E.; Mangan, B.

    2012-01-01

    We wanted to investigate the visual outcome of horses presented with iris prolapse and treated with corneal transplantation.......We wanted to investigate the visual outcome of horses presented with iris prolapse and treated with corneal transplantation....

  10. Clinical observation of corneal lamellar debridement combined with sutureless amniotic membrane transplantation for the treatment of superficial fungal keratitis

    Huang Zhang

    2014-09-01

    Full Text Available AIM:To evaluate the clinical efficacy of corneal lamellar debridement combined with sutureless amniotic membrane transplantation for the treatment of superficial fungal keratitis.METHODS:Totally 22 cases(22 eyeswith superficial fungal keratitis were referred to our hospital from April 2012 to October 2013. The patients with persistent cornea ulcer after treatment of local and systemic antifungal drugs underwent corneal lamellar debridement combined with sutureless amniotic membrane transplantation, and the recipient bed was covered with an amniotic membrane using fibrin sealant during the operation. All patients were still given topical antifungal therapy for 1-2mo after operation. The followed-up time was 3mo or above. We observed the corneal healing and amniotic membrane adhesion by split lamp microscope, and investigated the transformation of amniotic membrane and fungal infection recurrence with confocal microscope. RESULTS: Corneal edema and anterior chamber reaction of 21 patients disappeared gradually, and no amniotic membrane graft dissolved and shed off within 1-2wk postoperatively. Two weeks after operation, the graft integrated into the corneal and the corneal wounds' thickness increased gradually, the corneal epithelium reconstructed and corneas became clear. Four weeks after operation, the corneal scarring developed gradually and fluorescence staining was negative. Nineteen cases' amniotic membranes that adhered with the cornea dissolved 4wk after operation. There were different degrees of corneal nebula or macula remained 3mo postoperatively. All patients' vision improved in varying degrees, except in 1 case with fungal keratitis who had been cured by lamellar keratoplasty.CONCLUSION:Corneal lamellar debridement combined with sutureless amniotic membrane transplantation can effectively remove the foci of inflammation, improve the local efficacy, shorten the operation time, relieve the postoperative reaction, and promote cornea

  11. Anterior corneal profile with variable asphericity.

    Rosales, Marco A; Juárez-Aubry, Montserrat; López-Olazagasti, Estela; Ibarra, Jorge; Tepichín, Eduardo

    2009-12-10

    We present a corneal profile in which the eccentricity, e(Q=-e(2)), has a nonlinear continuous variation from the center outwards. This nonlinear variation is intended to fit and reproduce our current experimental data in which the anterior corneal surface of the human eye exhibits different values of e at different diameters. According to our clinical data, the variation is similar to an exponential decay. We propose a linear combination of two exponential functions to describe the variation of e. We then calculate the corneal sagittal height by substituting e in the first-order aspherical surface equation to obtain the corneal profile. This corneal profile will be used as a reference to analyze the resultant profiles of the customized corneal ablation in refractive surgery.

  12. Topical thrombin-related corneal calcification.

    Kiratli, Hayyam; Irkeç, Murat; Alaçal, Sibel; Söylemezoğlu, Figen

    2006-09-01

    To report a highly unusual case of corneal calcification after brief intraoperative use of topical thrombin. A 44-year-old man underwent sclerouvectomy for ciliochoroidal leiomyoma, during which 35 UNIH/mL lyophilized bovine thrombin mixed with 9 mL of diluent containing 1500 mmol/mL calcium chloride was used. From the first postoperative day, corneal and anterior lenticular capsule calcifications developed, and corneal involvement slightly enlarged thereafter. A year later, 2 corneal punch biopsies confirmed calcification mainly in the Bowman layer. Topical treatment with 1.5% ethylenediaminetetraacetic acid significantly restored corneal clarity. Six months later, a standard extracapsular cataract extraction with intraocular lens placement improved visual acuity to 20/60. This case suggests that topical thrombin drops with elevated calcium concentrations may cause acute corneal calcification in Bowman layer and on the anterior lens capsule.

  13. Thickness of the oligo-neogene sedimentary cover in the Central Depression, northern Chile (Pampa del Tamarugal, 20°45'-21°30'S), based on seismic reflection

    Garcia, M.; Simicic, Y.; Contreras Reyes, E.; Charrier, R.

    2013-12-01

    The estimation of the Pampa de Tamarugal oligo-neogene sedimentary cover thickness from seismic interpretation is crucial for scientific and applied subjects, such as placing aquifers traps and Mesozoic-Paleogene basement top location for mining exploration drilling. The Chilean National Petroleum Company (ENAP) has explored hydrocarbon resources in the area, raising several reflection seismic lines and drilling some wells. Previous studies used the paper seismic data by determining the cover geometry and defining the basement-cover boundary. We have obtained directly SGY digital files, which allow a better definition and modeling of stratigraphy and cover thickness. This thickness was estimated by the travel time in the seismic reflection lines and the value of the p-wave propagation velocity (0.91 to 1.97 km/s for cover). The last value was obtained by density measurements of field samples, which resulted from 1,895 to 2,065 g/cm3. In the central-south part of the Pampa del Tamarugal, immediately south of Cerro Challacollo, the west-east-oriented 99_7 seismic line shows a 'basement high' whose top is at 100 m from the surface. The basement was uplift by a north-trend west-verging reverse fault and separates two sub-basins of 9.5 km and 13.8 km wide, and maximum cover thicknesses of 600 and 850 m, west and east respectively. To the north of Cerro Challacollo, the subparallel 99_6 line shows a similar geometry, and increasing the depth of the basement high top up to 350 m in the central part of the section. For seismic lines south of Cerro Challacollo, the basement high disappears and the cover thickness increases. To improve the accuracy of the cover thickness estimations, we will test directly measurements of p-wave propagation velocity in field samples of basement and cover (instead of approximations from the density measurements).

  14. Ultrastructural analysis of corneal exposure to UV radiation

    Pitts, D.G.; Bergmanson, J.P.G.; Chu, L.W.-F.

    1987-01-01

    The primate cornea was exposed to 300 nm UVR with five levels of radiant expsure from 0.08 to 0.6 Jcm/sup -2/. All cellular layers of the cornea were damaged at the 0.08 Jcm/sup -2/ exposure, and damage became more severe as the exposure level was increased. The corneal cells showed variable response in that essentially normal cells were found among damaged cells. Eight days post-exposure using the 0.6 Jcm/sup -2/ level, the epithelium had regained its normal thickness and was populated largely by normal appearing cells; however, the stroma showed damaged keratocytes and the loss of keratocytes. The corneal basement membranes (the epithelial basement membrane and the posterior limiting lamina) and the anterior limiting lamina were not damaged at any exposure level except for an isolated area along the epithelial basement membrane in one cornea. Therefore, one is lead to conclude that basement membranes are unaffected by UVR. The endothelium continued to demonstrate the loss of mitochondria, endoplasmic reticulum and some vacuoles at 8 days after exposure. However, the endothelium appeared to have resumed its physiological function as demonstrated by the reduced stromal oedema. This research gives the first complete description of UV-B induced corneal damage and repair of the full, in-depth cornea of the primate using the EM.

  15. Ultrastructural analysis of corneal exposure to UV radiation

    Pitts, D.G.; Bergmanson, J.P.G.; Chu, L. W-F.

    1987-01-01

    The primate cornea was exposed to 300 nm UVR with five levels of radiant expsure from 0.08 to 0.6 Jcm -2 . All cellular layers of the cornea were damaged at the 0.08 Jcm -2 exposure, and damage became more severe as the exposure level was increased. The corneal cells showed variable response in that essentially normal cells were found among damaged cells. Eight days post-exposure using the 0.6 Jcm -2 level, the epithelium had regained its normal thickness and was populated largely by normal appearing cells; however, the stroma showed damaged keratocytes and the loss of keratocytes. The corneal basement membranes (the epithelial basement membrane and the posterior limiting lamina) and the anterior limiting lamina were not damaged at any exposure level except for an isolated area along the epithelial basement membrane in one cornea. Therefore, one is lead to conclude that basement membranes are unaffected by UVR. The endothelium continued to demonstrate the loss of mitochondria, endoplasmic reticulum and some vacuoles at 8 days after exposure. However, the endothelium appeared to have resumed its physiological function as demonstrated by the reduced stromal oedema. This research gives the first complete description of UV-B induced corneal damage and repair of the full, in-depth cornea of the primate using the EM. (author)

  16. Intra-Ocular Pressure Measurement in a Patient with a Thin, Thick or Abnormal Cornea.

    Clement, Colin I; Parker, Douglas G A; Goldberg, Ivan

    2016-01-01

    Accurate measurement of intra-ocular pressure is a fundamental component of the ocular examination. The most common method of measuring IOP is by Goldmann applanation tonometry, the accuracy of which is influenced by the thickness and biomechanical properties of the cornea. Algorithms devised to correct for corneal thickness to estimate IOP oversimplify the effects of corneal biomechanics. The viscous and elastic properties of the cornea influence IOP measurements in unpredictable ways, a finding borne out in studies of patients with inherently abnormal and surgically altered corneal biomechanics. Dynamic contour tonometry, rebound tonometry and the ocular response analyzer provide useful alternatives to GAT in patients with abnormal corneas, such as those who have undergone laser vision correction or keratoplasty. This article reviews the various methods of intra-ocular pressure measurement available to the clinician and the ways in which their utility is influenced by variations in corneal thickness and biomechanics.

  17. Corneal iron ring after conductive keratoplasty.

    Kymionis, George D; Naoumidi, Tatiana L; Aslanides, Ioannis M; Pallikaris, Ioannis G

    2003-08-01

    To report formation of corneal iron ring deposits after conductive keratoplasty. Observational case report. Case report. A 54-year-old woman underwent conductive keratoplasty for hyperopia. One year after conductive keratoplasty, iron ring pattern pigmentation was detected at the corneal epithelium of both eyes. This is the first report of the appearance of corneal iron ring deposits following conductive keratoplasty treatment in a patient. It is suggested that alterations in tear film stability, resulting from conductive keratoplasty-induced changes in corneal curvature, constitute the contributory factor for these deposits.

  18. Characteristics of corneal biomechanical responses detected by a non-contact scheimpflug-based tonometer in eyes with glaucoma.

    Jung, Younhea; Park, Hae-Young L; Yang, Hee Jung; Park, Chan Kee

    2017-11-01

    To determine the corneal biomechanical properties in eyes with glaucoma using a non-contact Scheimpflug-based tonometer. Corneal biomechanical responses were examined using a non-contact Scheimpflug-based tonometer. The tonometer parameters of the normal control group (n = 75) were compared with those of the glaucoma group (n = 136), including an analysis of glaucoma subgroups categorized by visual field loss. After adjusting for potential confounding factors, including the intraocular pressure (IOP), central corneal thickness (CCT), age and axial length, the deformation amplitude was smaller in the glaucoma group (1.09 ± 0.02 mm) than in the normal control group (1.12 ± 0.02 mm; p value = 0.031). The deformation amplitude and the deflection amplitude of the severe glaucoma group (1.12 ± 0.02 mm and 0.92 ± 0.01 mm) were significantly greater than that of the early glaucoma group (1.07 ± 0.01   mm and 0.88 ± 0.11 mm, p = 0.006 and p = 0.031), whereas that of the moderate glaucoma group (1.09 ± 0.02 mm and 0.90 ± 0.02 mm) was greater than that of the early glaucoma group, but this difference was not statistically significant. The deformation amplitude showed a negative correlation with the CCT in the normal control group (r = -0.235), with a weaker negative relationship observed in the early glaucoma group (r = -0.099). However, in the moderate and severe glaucoma groups, the deformation amplitude showed a positive relationship with the CCT, showing an inverse relationship. The duration and number of antiglaucomatous eyedrops used had negative correlations with the CCT in eyes with moderate and severe glaucoma. Overall, the glaucoma group showed significantly less deformable corneas than did the normal controls, even after adjusting for the IOP, CCT, age and axial length. However, there were also differences according to the severity of glaucoma, where the corneal deformation amplitude was greater in the severe glaucoma

  19. Thick Toenails

    ... in individuals with nail fungus (onychomycosis), psoriasis and hypothyroidism. Those who have problems with the thickness of their toenails should consult a foot and ankle surgeon for proper diagnosis and treatment. Find an ACFAS Physician Search Search Tools Find ...

  20. Effects of epidermal growth factor in artificial tear on vitamin C levels of corneal wounded eye tissues.

    Gönül, B; Kaplan, B; Bilgihan, K; Budak, M T

    2001-04-01

    To investigate the effect of artificial tear (AT) solution and epidermal growth factor (EGF) treatment on the cornea and aqueous humour ascorbic acid (AA) levels of full-thickness corneal wounded eyes. The effect of EGF on the AA levels of aqueous humour and corneal wound tissue was determined in full-thickness corneal wounded rabbit eyes on the seventh post-operative day. There were three groups: untreated controls, AT-treated controls and an EGF+AT-treated experimental group (n = 6 in each group). Corneal wounded eyes were topically treated with 5 microl AT or 5 microl EGF in AT (1 mg/l EGF in AT prepaaration which contained 3.0% carbopol 940) twice daily for 6 days after operation. The wound strengths were also measured on the seventh post-operative day as a measure of wound healing. Statistical analysis was carried out using the Mann-Whitney U-test by Statview program. The wound strengths of corneas, and AA levels of wound tissues and aqueous humour, increased significantly following AT and EGF treatment (p < 0.05). In the corneal wounded eye, aqueous humour serves as a source of vitamin C and there may be a relation between EGF treatment in AT and AA levels of corneal wounded eye tissues.

  1. Area and depth of surfactant-induced corneal injury predicts extent of subsequent ocular responses.

    Jester, J V; Petroll, W M; Bean, J; Parker, R D; Carr, G J; Cavanagh, H D; Maurer, J K

    1998-12-01

    To correlate area and depth of initial corneal injury induced by surfactants of differing type and irritant properties with corneal responses and outcome in the same animals over time by using in vivo confocal microscopy (CM). Six groups of six adult rabbits were treated with anionic, cationic, and nonionic surfactants that caused different levels of ocular irritation. Test materials included slight irritants: 5% sodium lauryl sulfate (SLS), polyoxyethylene glycol monoalkyl ether (POE), and 5% 3-isotridecyloxypropyl-bis(polyoxyethylene) ammonium chloride (ITDOP); mild irritants: 5% 3-decyloxypropyl-bis(polyoxyethylene) amine (DOP) and sodium linear alkylbenzene sulfonate (LAS); and a moderate irritant: a proprietary detergent (DTRGT). Ten microliters surfactant were directly applied to the cornea of one eye of each rabbit. Ten untreated rabbits served as control subjects. Area and depth of initial injury was determined by using in vivo CM to measure epithelial thickness, epithelial cell size, corneal thickness, and depth of stromal injury in four corneal regions at 3 hours and at day 1. Area and depth of corneal responses to injury were evaluated at various times from days 3 through 35 by macroscopic grading and quantitative confocal microscopy through-focusing (CMTF). In vivo CM revealed corneal injury with slight irritants to be restricted to the epithelium, whereas the mild and moderate irritants caused complete epithelial cell loss with increasing anterior stromal damage: DOP < LAS < DTRGT. With the slight ocular irritants there was little or no change in corneal thickness or the CMTF intensity profiles. Three hours after treatment, mild and moderate ocular irritants caused a significant increase in corneal thickness, which peaked at day 1 with DOP (483.3+/-80.1 microm) and LAS (572.3+/-60.0 microm) and day 3 with DTRGT (601.4+/-68.7 microm); returning to normal (similar to control values) by day 7 with DOP and day 35 with LAS and DTRGT. The CMTF intensity

  2. Evaluation of corneal changes after myopic LASIK using the Pentacam®

    Khairat YM

    2013-09-01

    Full Text Available Yehia M Khairat, Yasser H Mohamed, Ismail ANO Moftah, Narden N Fouad Department of Ophthalmology, Faculty of Medicine, El-Minya University, Egypt Background: In this study, we used a Pentacam® device to evaluate the corneal changes that occur after laser-assisted in situ keratomileusis (LASIK. Methods: Our study included 60 eyes of 32 patients. All patients were treated for myopia and myopic astigmatism using LASIK. The eyes were examined preoperatively and 3 months postoperatively using a Pentacam to assess corneal changes with regard to curvature, elevation, and asphericity of the cornea. Results: A statistically significant decrease in mean keratometric power of the anterior corneal surface (P = 0.001 compared with its pre-LASIK value was detected after 3 months, but there was no significant change in keratometric power of the posterior surface (P = 0.836. Asphericity (Q-value of the anterior and posterior surfaces increased significantly after LASIK (P = 0.001. A significant forward bulge of the anterior corneal surface 4 mm and 7 mm from the central zone was detected 3 months post-LASIK (P = 0.001 for both, but there was no significant increase in posterior elevation at 4 mm and 7 mm from the center (P = 0.637 and P = 0.26, respectively. No cases of post-LASIK ectasia were detected. Correlation between different parameters of the corneal surface revealed an indirect relation between changes in pachymetry and anterior corneal elevation at 4 mm and 7 mm from the central zone (r = −0.27, P = 0.13, and r = −0.37, P = 0.04, respectively, and a direct proportion between changes in pachymetry and mean keratometric power of the anterior and posterior corneal surfaces (r = 0.7, P = 0.001 and r = 0.4, P = 0.028, respectively. Conclusion: LASIK causes significant changes at the anterior corneal surface but the effect is subtle and insignificant at the posterior surface. Keywords: LASIK, laser-assisted in situ keratomileusis, Pentacam®, corneal

  3. The outer vactank, an object of 7.6m diameter and 13m length is built up of three cylindrical parts. The central part that is integral part of the central barrel and the the extension on either side each one 4.5m long. These extensions house the shoulders that will support and prestress the CMS Coil. To weld the extensions onto the central part a full penetration weld of 24m length and 45 mm thickness has to be done by hand from inside and outside the vacuum tank and its deformation is controled permanently.

    Hubert Gerwig

    2001-01-01

    The outer vacuum tank will hold the coil suspension system and transmits the weight of the inner detectors to the central barrel. Its thickness is staggered. In the central part its thickness is 60 mm and then goes down to 30 mm at the extremity.

  4. Rechazo y retrasplante corneal Corneal rejection and re-transplantation

    Miguel O Mokey Castellanos

    2007-06-01

    Full Text Available Se efectuó una investigación observacional análítica retrospectiva, sobre los transplantes corneales efectuados en el Servicio de Oftalmología del Hospital "Hermanos Ameijeiras. Rechazaron 76 pacientes, que se compararon con un control de 89 pacientes, que en un período similar no tuvieron rechazo. El queratocono fue la afección corneal que predominó. El primer lugar en los rechazos correspondió a queratoherpes (43,5 %. El menor índice de rechazo fue para el queratocono (8,8 %. Se analizó la multiplicidad de rechazos; y fue frecuente que se presentara un solo rechazo, aunque sí hubo congruencia entre el número de rechazos y la necesidad de retrasplantes. Se encontró que los resultados de la conducta médica o quirúrgica se relacionaban con la causa. Se calcula un índice de supervivencia (Kaplan-Meier, que concluye que en los primeros dos años existe menos posibilidad de aparición de rechazoAn retrospective observational analytical research was conducted on corneal transplants performed at Ophthalmological Service in “Hermanos Ameijeiras” hospital . Seventy six patients had graft rejection and were compared to a control group of 89 patients that did not present rejection in the same period of time. Keratoconus was the prevailing corneal problem. The highest rejection rate corresponded to keratoherpes (43,5% whereas the lowest rate was for keratoconus (8,8%. Multiplicity of rejections was analyzed and it was found that mostly one graft rejection occured, but number of rejections was associated with the need of re-transplantation. It was found that the results of medical or surgical performance were related to the cause of graft rejection. A survival index (Kaplan-Meier was estimated, which showed that occurence of graf rejection is less probable in the first two years

  5. Corynebacterium macginleyi isolated from a corneal ulcer

    Kathryn Ruoff

    2010-02-01

    Full Text Available We report the isolation of Corynebacterium macginleyi from the corneal ulcer culture of a patient, later enrolled in the Steroids for Corneal Ulcer Trial (SCUT. To our knowledge this is the first published report from North America of the recovery of C. macginleyi from a serious ocular infection.

  6. Do topical antibiotics help corneal epithelial trauma?

    King, J. W.; Brison, R. J.

    1993-01-01

    Topical antibiotics are routinely used in emergency rooms to treat corneal trauma, although no published evidence supports this treatment. In a noncomparative clinical trial, 351 patients with corneal epithelial injuries were treated without antibiotics. The infection rate was 0.7%, suggesting that such injuries can be safely and effectively managed without antibiotics. A comparative clinical trial is neither warranted nor feasible.

  7. Designing Hydrogel Adhesives for Corneal Wound Repair

    Grinstaff, Mark W.

    2013-01-01

    Today, corneal wounds are repaired using nylon sutures. Yet there are a number of complications associated with suturing the cornea, and thus there is interest in an adhesive to replace or supplement sutures in the repair of corneal wounds. We are designing and evaluating corneal adhesives prepared from dendrimers – single molecular weight, highly branched polymers. We have explored two strategies to form these ocular adhesives. The first involves a photocrosslinking reaction and the second uses a peptide ligation reactions to couple the individual dendrimers together to from the adhesive. These adhesives were successfully used to repair corneal perforations, close the flap produced in a LASIK procedure, and secure a corneal transplant. PMID:17889330

  8. Healed corneal ulcer with keloid formation.

    Alkatan, Hind M; Al-Arfaj, Khalid M; Hantera, Mohammed; Al-Kharashi, Soliman

    2012-04-01

    We are reporting a 34-year-old Arabic white female patient who presented with a white mass covering her left cornea following multiple ocular surgeries and healed corneal ulcer. The lesion obscured further view of the iris, pupil and lens. The patient underwent penetrating keratoplasty and the histopathologic study of the left corneal button showed epithelial hyperplasia, absent Bowman's layer and subepithelial fibrovascular proliferation. The histopathologic appearance was suggestive of a corneal keloid which was supported by further ultrastructural study. The corneal graft remained clear 6 months after surgery and the patient was satisfied with the visual outcome. Penetrating keratoplasty may be an effective surgical option for corneal keloids in young adult patients.

  9. Using H/V Spectral Ratio Analysis to Map Sediment Thickness and to Explain Macroseismic Intensity Variation of a Low-Magnitude Seismic Swarm in Central Belgium

    Van Noten, K.; Lecocq, T.; Camelbeeck, T.

    2013-12-01

    Between 2008 and 2010, the Royal Observatory of Belgium received numerous ';Did You Feel It'-reports related to a 2-year lasting earthquake swarm at Court-Saint-Etienne, a small town in a hilly area 20 km SE of Brussels, Belgium. These small-magnitude events (-0.7 ≤ ML ≤ 3.2, n = c. 300 events) were recorded both by the permanent seismometer network in Belgium and by a locally installed temporary seismic network deployed in the epicentral area. Relocation of the hypocenters revealed that the seismic swarm can be related to the reactivation of a NW-SE strike-slip fault at 3 to 6 km depth in the basement rocks of the Lower Palaeozoic London-Brabant Massif. This sequence caused a lot of emotion in the region because more than 60 events were felt by the local population. Given the small magnitudes of the seismic swarm, most events were more often heard than felt by the respondents, which is indicative of a local high-frequency earthquake source. At places where the bedrock is at the surface or where it is covered by thin alluvial sediments ( 30 m). In those river valleys that have a considerable alluvial sedimentary cover, macroseismic intensities are again lower. To explain this variation in macroseismic intensity we present a macroseismic analysis of all DYFI-reports related to the 2008-2010 seismic swarm and a pervasive H/V spectral ratio (HVSR) analysis of ambient noise measurements to model the thickness of sediments covering the London-Brabant Massif. The HVSR method is a very powerful tool to map the basement morphology, particularly in regions of unknown subsurface structure. By calculating the soil's fundamental frequency above boreholes, we calibrated the power-law relationship between the fundamental frequency, shear wave velocity and the thickness of sediments. This relationship is useful for places where the sediment thickness is unknown and where the fundamental frequency can be calculated by H/V spectral ratio analysis of ambient noise. In a

  10. NK cells modulate the inflammatory response to corneal epithelial abrasion and thereby support wound healing

    Natural killer cells are lymphocytes of the innate immune system that have crucial cytotoxic and regulatory roles in adaptive immunity and inflammation. Herein, we consider a role for these cells in corneal wound healing. After a 2-mm central epithelial abrasion of the mouse cornea, a subset of clas...

  11. Corneal modeling for analysis of photorefractive keratectomy

    Della Vecchia, Michael A.; Lamkin-Kennard, Kathleen

    1997-05-01

    Procedurally, excimer photorefractive keratectomy is based on the refractive correction of composite spherical and cylindrical ophthalmic errors of the entire eye. These refractive errors are inputted for correction at the corneal plane and for the properly controlled duration and location of laser energy. Topography is usually taken to correspondingly monitor spherical and cylindrical corneorefractive errors. While a corneal topographer provides surface morphologic information, the keratorefractive photoablation is based on the patient's spherical and cylindrical spectacle correction. Topography is at present not directly part of the procedural deterministic parameters. Examination of how corneal curvature at each of the keratometric reference loci affect the shape of the resultant corneal photoablated surface may enhance the accuracy of the desired correction. The objective of this study was to develop a methodology to utilize corneal topography for construction of models depicting pre- and post-operative keratomorphology for analysis of photorefractive keratectomy. Multiple types of models were developed then recreated in optical design software for examination of focal lengths and other optical characteristics. The corneal models were developed using data extracted from the TMS I corneal modeling system (Computed Anatomy, New York, NY). The TMS I does not allow for manipulation of data or differentiation of pre- and post-operative surfaces within its platform, thus models needed to be created for analysis. The data were imported into Matlab where 3D models, surface meshes, and contour plots were created. The data used to generate the models were pre- and post-operative curvatures, heights from the corneal apes, and x-y positions at 6400 locations on the corneal surface. Outlying non-contributory points were eliminated through statistical operations. Pre- and post- operative models were analyzed to obtain the resultant changes in the corneal surfaces during PRK

  12. Evaluation of the cytotoxic effects of ophthalmic solutions containing benzalkonium chloride on corneal epithelium using an organotypic 3-D model

    Jessen Bart A

    2009-07-01

    Full Text Available Abstract Background Benzalkonium chloride (BAC is a common preservative used in ophthalmic solutions. The aim of this study was to compare the cytotoxic effects of BAC-containing ophthalmic solutions with a BAC-free ophthalmic solution using an organotypic 3-dimensional (3-D corneal epithelial model and to determine the effects of latanoprost ophthalmic solution and its BAC-containing vehicle on corneal thickness in a monkey model. Methods The cytotoxicity of commercially available BAC-containing ophthalmic formulations of latanoprost (0.02% BAC and olopatadine (0.01% BAC was compared to that of BAC-free travoprost and saline in a corneal organotypic 3-D model using incubation times of 10 and 25 minutes. To compare the extent of differentiation of 3-D corneal cultures to monolayer transformed human corneal epithelial (HCE-T cell cultures, expression levels (mRNA and protein of the corneal markers epidermal growth factor receptor, transglutaminase 1 and involucrin were quantified. Finally, latanoprost ophthalmic solution or its vehicle was administered at suprapharmacologic doses (two 30 μL drops twice daily in 1 eye for 1 year in monkey eyes, and corneal pachymetry was performed at baseline and at weeks 4, 13, 26 and 52. Results In the 3-D corneal epithelial culture assays, there were no significant differences in cytotoxicity between the BAC-containing latanoprost and olopatadine ophthalmic solutions and BAC-free travoprost ophthalmic solution at either the 10- or 25-minute time points. The 3-D cultures expressed higher levels of corneal epithelial markers than the HCE-T monolayers, indicating a greater degree of differentiation. There were no significant differences between the corneal thickness of monkey eyes treated with latanoprost ophthalmic solution or its vehicle (both containing 0.02% BAC and untreated eyes. Conclusion The lack of cytotoxicity demonstrated in 3-D corneal cultures and in monkey studies suggests that the levels of BAC

  13. Optical coherence tomography of the effects of stromal hydration on clear corneal incision architecture.

    Calladine, Daniel; Tanner, Vaughan

    2009-08-01

    To evaluate the effects of stromal hydration on clear corneal incision (CCI) architecture immediately after surgery using anterior segment optical coherence tomography (AS-OCT). Department of Ophthalmology, Royal Berkshire Hospital, Reading, United Kingdom. Clear corneal incisions in adult eyes were examined using a Visante AS-OCT imaging system within 1 hour of surgery. Half the CCIs had stromal hydration with a balanced salt solution and half did not. Incisions were made with a 2.75 mm steel keratome. Intraocular pressure (IOP) was measured within 90 minutes after surgery. The CCI length and corneal thickness at the CCI site were measured using software built into the AS-OCT system. Thirty CCIs were evaluated. Stromal hydration significantly increased the measured CCI length (Pthe result of a trend toward increased corneal thickness at the CCI site with hydration (PThe mean CCI length was 1.69 mm +/- 0.27 (SD) (range 1.31 to 2.32 mm) with hydration and 1.51 +/- 0.23 mm (range 1.30 to 1.95 mm) without hydration. The mean IOP was 20.9 +/- 8.18 mm Hg and 15.8 +/- 8.20 mm Hg, respectively. The IOP tended to be higher with hydration (Pthe eye with a higher early postoperative IOP, showing the importance of taking stromal hydration into account when designing similar OCT studies of CCI architecture.

  14. Corticosteroids for bacterial keratitis: the Steroids for Corneal Ulcers Trial (SCUT).

    Srinivasan, Muthiah; Mascarenhas, Jeena; Rajaraman, Revathi; Ravindran, Meenakshi; Lalitha, Prajna; Glidden, David V; Ray, Kathryn J; Hong, Kevin C; Oldenburg, Catherine E; Lee, Salena M; Zegans, Michael E; McLeod, Stephen D; Lietman, Thomas M; Acharya, Nisha R

    2012-02-01

    To determine whether there is a benefit in clinical outcomes with the use of topical corticosteroids as adjunctive therapy in the treatment of bacterial corneal ulcers. Randomized, placebo-controlled, double-masked, multicenter clinical trial comparing prednisolone sodium phosphate, 1.0%, to placebo as adjunctive therapy for the treatment of bacterial corneal ulcers. Eligible patients had a culture-positive bacterial corneal ulcer and received topical moxifloxacin for at least 48 hours before randomization. The primary outcome was best spectacle-corrected visual acuity (BSCVA) at 3 months from enrollment. Secondary outcomes included infiltrate/scar size, reepithelialization, and corneal perforation. Between September 1, 2006, and February 22, 2010, 1769 patients were screened for the trial and 500 patients were enrolled. No significant difference was observed in the 3-month BSCVA (-0.009 logarithm of the minimum angle of resolution [logMAR]; 95% CI, -0.085 to 0.068; P = .82), infiltrate/scar size (P = .40), time to reepithelialization (P = .44), or corneal perforation (P > .99). A significant effect of corticosteroids was observed in subgroups of baseline BSCVA (P = .03) and ulcer location (P = .04). At 3 months, patients with vision of counting fingers or worse at baseline had 0.17 logMAR better visual acuity with corticosteroids (95% CI, -0.31 to -0.02; P = .03) compared with placebo, and patients with ulcers that were completely central at baseline had 0.20 logMAR better visual acuity with corticosteroids (-0.37 to -0.04; P = .02). We found no overall difference in 3-month BSCVA and no safety concerns with adjunctive corticosteroid therapy for bacterial corneal ulcers. Adjunctive topical corticosteroid use does not improve 3-month vision in patients with bacterial corneal ulcers. clinicaltrials.gov Identifier: NCT00324168.

  15. Alloimmunity and Tolerance in Corneal Transplantation.

    Amouzegar, Afsaneh; Chauhan, Sunil K; Dana, Reza

    2016-05-15

    Corneal transplantation is one of the most prevalent and successful forms of solid tissue transplantation. Despite favorable outcomes, immune-mediated graft rejection remains the major cause of corneal allograft failure. Although low-risk graft recipients with uninflamed graft beds enjoy a success rate ∼90%, the rejection rates in inflamed graft beds or high-risk recipients often exceed 50%, despite maximal immune suppression. In this review, we discuss the critical facets of corneal alloimmunity, including immune and angiogenic privilege, mechanisms of allosensitization, cellular and molecular mediators of graft rejection, and allotolerance induction. Copyright © 2016 by The American Association of Immunologists, Inc.

  16. Corneal iron ring after hyperopic photorefractive keratectomy.

    Bilgihan, K; Akata, F; Gürelik, G; Adigüzel, U; Akpinar, M; Hasanreisoğlu, B

    1999-05-01

    To report the incidence and course of corneal iron deposition after hyperopic photorefractive keratectomy (PRK). Gazi University, Medical School, Department of Ophthalmology, Ankara, Turkey. Between January 1995 and December 1997, 62 eyes had PRK to correct hyperopia. Nine eyes developed corneal iron ring 5 to 8 months (mean 6.25 months +/- 1.3 [SD]) after PRK for hyperopia. The rings persisted during the mean follow-up of 19 +/- 11.09 months. The ring-shaped iron deposition after PRK for hyperopia must be differentiated from the Fleischer ring. Our results suggest that the slitlamp findings of peripheral corneal iron deposition in hyperopic PRK patients correlate with achieved correction.

  17. A Case of Medication-Resistant Acanthamoeba Keratitis Treated by Corneal Crosslinking in Turkey

    Goktug Demirci

    2013-01-01

    Full Text Available Purpose. To report a case of medication-resistant acanthamoeba keratitis (AK treated successfully by corneal crosslinking (CXL. Methods. A 26-year-old male with medication-resistant AK underwent a standard CXL procedure with local anesthesia, followed by central corneal epithelial debridement, application of riboflavin 0.1%, and UV-A irradiation. Results. The patient experienced a dramatic symptomatic improvement within 24 hours. At two months, keratitis was healed with a semitransparent paracentral scar that did not affect visual acuity. Conclusions. Our experience, considered in the context of recent studies, suggests that CXL may be an option for selected patients with medication-resistant AK and corneal melting. CXL allows patients to avoid emergency keratoplasty and experience rapid symptomatic relief.

  18. Confocal comparison of corneal reinnervation after small incision lenticule extraction (SMILE and femtosecond laser in situ keratomileusis (FS-LASIK.

    Meiyan Li

    Full Text Available PURPOSE: To evaluate corneal reinnervation, and the corresponding corneal sensitivity and keratocyte density after small incision lenticule extraction (SMILE and femtosecond laser in situ keratomileusis (FS-LASIK. METHODS: In this prospective, non-randomized observational study, 18 patients (32 eyes received SMILE surgery, and 22 patients (42 eyes received FS-LASIK surgery to correct myopia. The corneal subbasal nerve density and microscopic morphological changes in corneal architecture were evaluated by confocal microscopy prior to surgery and at 1 week, 1 month, 3 months, and 6 months after surgery. A correlation analysis was performed between subbasal corneal nerve density and the corresponding keratocyte density and corneal sensitivity. RESULTS: The decrease in subbasal nerve density was less severe in SMILE-treated eyes than in FS-LASIK-treated eyes at 1 week (P = 0.0147, 1 month (P = 0.0243, and 3 months (P = 0.0498, but no difference was detected at the 6-month visit (P = 0.5277. The subbasal nerve density correlated positively with central corneal sensitivity in both groups (r = 0.416, P<0.0001, and r = 0.2567, P = 0.0038 for SMILE group and FS-LASIK group, respectively. The SMILE-treated eyes have a lower risk of developing peripheral empty space with epithelial cells filling in (P = 0.0005. CONCLUSIONS: The decrease in subbasal nerve fiber density was less severe in the SMILE group than the FS-LASIK group in the first 3 months following the surgeries. The subbasal nerve density was correlated with central corneal sensitivity.

  19. CHANGES IN CHOROIDAL THICKNESS IN AND OUTSIDE THE MACULA AFTER HEMODIALYSIS IN PATIENTS WITH END-STAGE RENAL DISEASE.

    Chang, In Boem; Lee, Jeong Hyun; Kim, Jae Suk

    2017-05-01

    To evaluate changes in choroidal thickness in and outside the macula as a result of hemodialysis (HD) in patients with end-stage renal disease. Patients with end-stage renal disease treated with maintenance HD in the Dialysis Unit of Sanggye Paik Hospital, Seoul, South Korea, were included in this study. The choroidal thickness was measured in and outside the macula before and after HD (paired t-test). Choroidal thickness in the macula was measured at the foveal center and 1.5 mm temporal to the foveal center and outside the macula was measured at superior, inferior, and nasal area 3.5 mm from the optic disk margin. Peripapillary retinal nerve fiber layer thickness, intraocular pressure, central corneal thickness, and systemic parameters such as serum osmolarity and blood pressure (BP) were measured before and after HD (paired t-test). We divided patients into two groups, diabetic and nondiabetic groups to compare the changes in choroidal thickness. Patients with diabetes were subdivided into two groups: severe retinal change group and moderate retinal change group (Mann-Whitney test). Pearson's correlation test was used to evaluate the correlations between choroidal thickness and changes in serum osmolarity, BP, and body weight loss. Choroidal thickness and peripapillary retinal nerve fiber layer thickness were measured using spectral-domain optical coherence tomography. Fifty-four eyes of 31 patients with end-stage renal disease were included. After HD, the mean intraocular pressure was significantly decreased from 14.8 ± 2.5 mmHg to 13.0 ± 2.6 mmHg (P macula.

  20. Expression of semaphorin 3A in the rat corneal epithelium during wound healing

    Morishige, Naoyuki; Ko, Ji-Ae; Morita, Yukiko; Nishida, Teruo

    2010-01-01

    The neural guidance protein semaphorin 3A (Sema3A) is expressed in corneal epithelial cells of the adult rat. We have now further investigated the localization of Sema3A in the normal rat corneal epithelium as well as changes in its expression pattern during wound healing after central corneal epithelial debridement. The expression pattern of Sema3A was compared with that of the tight-junction protein zonula occludens-1 (ZO-1), the gap-junction protein connexin43 (Cx43), or the cell proliferation marker Ki67. Immunofluorescence analysis revealed that Sema3A was present predominantly in the membrane of basal and wing cells of the intact corneal epithelium. The expression of Sema3A at the basal side of basal cells was increased in the peripheral epithelium compared with that in the central region. Sema3A was detected in all layers at the leading edge of the migrating corneal epithelium at 6 h after central epithelial debridement. The expression of Sema3A was markedly up-regulated in the basal and lateral membranes of columnar basal cells apparent in the thickened, newly healed epithelium at 1 day after debridement, but it had largely returned to the normal pattern at 3 days after debridement. The expression of ZO-1 was restricted to superficial epithelial cells and remained mostly unchanged during the wound healing process. The expression of Cx43 in basal cells was down-regulated at the leading edge of the migrating epithelium but was stable in the remaining portion of the epithelium. Ki67 was not detected in basal cells of the central epithelium at 1 day after epithelial debridement, when Sema3A was prominently expressed. Immunoblot analysis showed that the abundance of Sema3A in the central cornea was increased 1 day after epithelial debridement, whereas that of ZO-1 or Cx43 remained largely unchanged. This increase in Sema3A expression was accompanied by up-regulation of the Sema3A coreceptor neuropilin-1. Our observations have thus shown that the expression of

  1. Detecting thermal phase transitions in corneal stroma by fluorescence micro-imaging analysis

    Matteini, P.; Rossi, F.; Ratto, F.; Bruno, I.; Nesi, P.; Pini, R.

    2008-02-01

    Thermal modifications induced in corneal stroma were investigated by the use of fluorescence microscopy. Freshly extracted porcine corneas were immersed for 5 minutes in a water bath at temperatures in the 35-90°C range and stored in formalin. The samples were then sliced in 200-μm-thick transversal sections and analyzed under a stereomicroscope to assess corneal shrinkage. Fluorescence images of the thermally treated corneal samples were acquired using a slow-scan cooled CCD camera, after staining the slices with Indocyanine Green (ICG) fluorescent dye which allowed to detect fluorescence signal from the whole tissue. All measurements were performed using an inverted epifluorescence microscope equipped with a mercury lamp. The thermally-induced modifications to the corneal specimens were evaluated by studying the grey level distribution in the fluorescence images. For each acquired image, Discrete Fourier Transform (DFT) and entropy analyses were performed. The spatial distribution of DFT absolute value indicated the spatial orientation of the lamellar planes, while entropy was used to study the image texture, correlated to the stromal structural transitions. As a result, it was possible to indicate a temperature threshold value (62°C) for high thermal damage, resulting in a disorganization of the lamellar planes and in full agreement with the measured temperature for corneal shrinkage onset. Analysis of the image entropy evidenced five strong modifications in stromal architecture at temperatures of ~45°C, 53°C, 57°C, 66°C, 75°C. The proposed procedure proved to be an effective micro-imaging method capable of detecting subtle changes in corneal tissue subjected to thermal treatment.

  2. A Comparative Study of Vertebrate Corneal Structure: The Evolution of a Refractive Lens.

    Winkler, Moritz; Shoa, Golroxan; Tran, Stephanie T; Xie, Yilu; Thomasy, Sarah; Raghunathan, Vijay K; Murphy, Christopher; Brown, Donald J; Jester, James V

    2015-04-01

    Although corneal curvature plays an important role in determining the refractive power of the vertebrate eye, the mechanisms controlling corneal shape remain largely unknown. To address this question, we performed a comparative study of vertebrate corneal structure to identify potential evolutionarily based changes that correlate with the development of a corneal refractive lens. Nonlinear optical (NLO) imaging of second-harmonic-generated (SHG) signals was used to image collagen and three-dimensionally reconstruct the lamellar organization in corneas from different vertebrate clades. Second-harmonic-generated images taken normal to the corneal surface showed that corneal collagen in all nonmammalian vertebrates was organized into sheets (fish and amphibians) or ribbons (reptiles and birds) extending from limbus to limbus that were oriented nearly orthogonal (ranging from 77.7°-88.2°) to their neighbors. The slight angular offset (2°-13°) created a rotational pattern that continued throughout the full thickness in fish and amphibians and to the very posterior layers in reptiles and birds. Interactions between lamellae were limited to "sutural" fibers in cartilaginous fish, and occasional lamellar branching in fish and amphibians. There was a marked increase in lamellar branching in higher vertebrates, such that birds ≫ reptiles > amphibians > fish. By contrast, mammalian corneas showed a nearly random collagen fiber organization with no orthogonal, chiral pattern. Our data indicate that nonmammalian vertebrate corneas share a common orthogonal collagen structural organization that shows increased lamellar branching in higher vertebrate species. Importantly, mammalian corneas showed a different structural organization, suggesting a divergent evolutionary background.

  3. The relationship between corneal biomechanical properties and confocal microscopy findings in normal and keratoconic eyes.

    Hurmeric, Volkan; Sahin, Afsun; Ozge, Gokhan; Bayer, Atilla

    2010-06-01

    To investigate the relationship between corneal biomechanical properties and confocal microscopy (CM) findings in normal and keratoconic eyes. The study consisted of 28 eyes of 28 healthy volunteers and 23 eyes of 15 patients with keratoconus. The diagnosis of keratoconus was made with corneal topography and clinical findings. The corneal hysteresis (CH) and corneal resistance factor (CRF) were measured by the ocular response analyzer. In vivo CM was performed with NIDEK Confoscan 3. CH and CRF were compared with corneal morphological findings (detailed cell counts of endothelial, stromal, and epithelial cells) in vivo. CH was 10.1 +/- 1.3 mm Hg in normal eyes and 7.4 +/- 1.5 mm Hg in keratoconic eyes (P < 0.0001). CRF was 10.1 +/- 1.8 mm Hg in normal eyes and 6.2 +/- 1.4 mm Hg in keratoconic eyes (P < 0.0001). CH and CRF were negatively correlated with full-thickness stromal keratocyte density (P < 0.01; r = -0.52 and P < 0.001; r = -0.67, respectively) in healthy eyes. Keratocyte density of the posterior half of the stroma was found to be significantly related with CRF in healthy eyes (beta = -0.404; P = 0.01). There was no significant relationship among CH, CRF, and CM findings in eyes with keratoconus. There is a significant relationship between CRF and keratocyte density of the posterior half of the stroma in healthy eyes. Our results suggest that corneal elasticity is related to not only stromal matrix but also cellular structure of the cornea.

  4. Risk factors for corneal ectasia after LASIK.

    Tabbara, Khalid F; Kotb, Amgad A

    2006-09-01

    To establish a grading system that helps identify high-risk individuals who may experience corneal ectasia after LASIK. Retrospective, comparative, interventional case series. One hundred forty-eight consecutive patients (148 eyes) were included in this study. Thirty-seven patients who underwent LASIK at other refractive centers experienced corneal ectasia in 1 eye after LASIK. One hundred eleven eyes of 111 patients who underwent successful LASIK during the same period were age and gender matched and served as controls. All patients underwent preoperative and postoperative topographic analysis of the cornea. The follow-up period in both groups of patients ranged from 2 to 5 years, with a mean follow-up of 3.6 years. All patients underwent LASIK for myopia (spherical equivalent, -4.00 to -8.00 diopters). Corneal keratometry, oblique cylinder, pachymetry, posterior surface elevation, difference between the inferior and superior corneal diopteric power, and posterior best sphere fit (BSF) over anterior BSF were given a grade of 1 to 3 each. An ectasia grading system was established, and the cumulative risk score was assessed. Patients who had a grade of 7 or less showed no evidence of corneal ectasia, whereas 16 (59%) of 27 patients who had a grade of 8 to 12 had corneal ectasia. Twenty-one (100%) of 21 patients with a grade of more than 12 had corneal ectasia after LASIK (P<0.0001). A risk score may help in the prediction of patients who are at risk of experiencing corneal ectasia after LASIK. A prospective clinical study is needed to assess the validity of these risk factors.

  5. Healed corneal ulcer with keloid formation

    Alkatan, Hind M.; Al-Arfaj, Khalid M.; Hantera, Mohammed; Al-Kharashi, Soliman

    2012-01-01

    We are reporting a 34-year-old Arabic white female patient who presented with a white mass covering her left cornea following multiple ocular surgeries and healed corneal ulcer. The lesion obscured further view of the iris, pupil and lens. The patient underwent penetrating keratoplasty and the histopathologic study of the left corneal button showed epithelial hyperplasia, absent Bowman’s layer and subepithelial fibrovascular proliferation. The histopathologic appearance was suggestive of a co...

  6. Corneal elastosis within lattice dystrophy lesions.

    Pe'er, J; Fine, B S; Dixon, A; Rothberg, D S

    1988-01-01

    Corneal buttons of two patients with lattice corneal dystrophy were studied by light and electron microscopy. They showed elastotic degeneration within the amyloid deposits. The amyloid deposits displayed characteristic staining; the elastotic material (elastin) within the deposits stained positive with Verhoeff-van Gieson and Movat pentachrome stains and showed autofluorescence. The characteristic ultrastructural findings of amyloid and elastotic material were also demonstrated. The possibility of the associations of these two materials in the cornea is discussed. Images PMID:3258531

  7. Chlorpromazine-induced corneal endothelial phototoxicity

    Hull, D.S.; Csukas, S.; Green, K.

    1982-01-01

    Chlorpromazine, which has been used extensively for the treatment of psychiatric disorders, is known to accumulate in the posterior corneal stroma, lens, and uveal tract. Because it is a phototoxic compound, the potential exists for it to cause cellular damage after light exposure. Specular microscopic perfusion of corneal endothelial cells in darkness with 0.5 mM chlorpromazine HCl resulted in a swelling rate of 18 +/- 2 micrometer/hr, whereas corneas exposed to long-wavelength ultraviolet light for 3 min in the presence of 0.5 mM chlorpromazine swelled at 37 +/- 9 micrometer/hr (p less than 0.01). Preirradiation of 0.5 mM chlorpromazine solution with ultraviolet light for 30 min and subsequent corneal perfusion with the solution resulted in a corneal swelling rate of 45 +/- 19 micrometer/hr. Cornea endothelial cells perfused with 0.5 mM chlorpromazine that was preirradiated with ultraviolet light showed marked swelling on scanning electron microscopic examination, whereas those perfused with nonirradiated chlorpromazine were flat and showed a normal mosaic pattern. Combining either 500 U/ml catalase or 290 U/ml superoxide dismutase with chlorpromazine did not alter photoinduction of corneal swelling. The data suggest that corneal endothelial chlorpromazine phototoxicity is secondary to cytotoxic products resulting from the photodynamically induced decomposition of chlorpromazine and is not caused by hydrogen peroxide or superoxide anion generated during the phototoxic reaction

  8. Primary Outcomes of Accelerated Epithelium-Off Corneal Cross-Linking in Progressive Keratoconus in Children: A 1-Year Prospective Study

    Sherif A. Eissa

    2017-01-01

    Full Text Available Purpose. To evaluate corneal transparency following accelerated collagen cross-linking (ACXL in pediatric keratoconus. Design. A prospective interventional case series. Methods. This study included 47 eyes (25 patients, aged 9–14 years, with documented progressive keratoconus. After applying 0.1% riboflavin drops, ACXL was performed. Assessment included corrected distance visual acuity (CDVA, uncorrected visual acuity (UCVA, corneal haze, and corneal densitometry in grayscale units (GSU. Result. The mean baseline and corneal densitometry peaked at 3 months post-ACXL while central and posterior densitometry showed a statistically significant increase (P<0.05 and peaked at 8 months postoperatively. By 12 months, densitometry in all corneal layers (P≥0.99 and concentric zones (P≥0.97 reached near baseline values. Slit-lamp graded haze peaked at 1 month to 1.82 ± 0.65 (P<0.05 and declined to near baseline at 12 months (0.39 ± 0.58. There was a statistically significant increase in the mean UCVA and CDVA at 12 months. Conclusion. Total and anterior corneal densitometry peaked after 3 months, while central and posterior densitometry peaked after 8 months. Maximum haze was at 1 month post-ACXL. All corneal layers, concentric zone densitometry and haze reached near baseline values after 1 year. Scheimpflug densitometry showed weak correlation with CDVA over the 12-month follow-up period (r=−0.193.

  9. Low temperature corneal laser welding investigated by atomic force microscopy

    Matteini, Paolo; Sbrana, Francesca; Tiribilli, Bruno; Pini, Roberto

    2009-02-01

    The structural modifications in the stromal matrix induced by low-temperature corneal laser welding were investigated by atomic force microscopy (AFM). This procedure consists of staining the wound with Indocyanine Green (ICG), followed by irradiation with a near-infrared laser operated at low-power densities. This induces a local heating in the 55-65 °C range. In welded tissue, extracellular components undergo heat-induced structural modifications, resulting in a joining effect between the cut edges. However, the exact mechanism generating the welding, to date, is not completely understood. Full-thickness cuts, 3.5 mm in length, were made in fresh porcine cornea samples, and these were then subjected to laser welding operated at 16.7 W/cm2 power density. AFM imaging was performed on resin-embedded semi-thin slices once they had been cleared by chemical etching, in order to expose the stromal bulk of the tissue within the section. We then carried out a morphological analysis of characteristic fibrillar features in the laser-treated and control samples. AFM images of control stromal regions highlighted well-organized collagen fibrils (36.2 +/- 8.7 nm in size) running parallel to each other as in a typical lamellar domain. The fibrils exhibited a beaded pattern with a 22-39 nm axial periodicity. Laser-treated corneal regions were characterized by a significant disorganization of the intralamellar architecture. At the weld site, groups of interwoven fibrils joined the cut edges, showing structural properties that were fully comparable with those of control regions. This suggested that fibrillar collagen is not denatured by low-temperature laser welding, confirming previous transmission electron microscopy (TEM) observations, and thus it is probably not involved in the closure mechanism of corneal cuts. The loss of fibrillar organization may be related to some structural modifications in some interfibrillar substance as proteoglycans or collagen VI. Furthermore, AFM

  10. Simultaneous topography-guided PRK followed by corneal collagen cross-linking after lamellar keratoplasty for keratoconus.

    Spadea, Leopoldo; Paroli, Marino

    2012-01-01

    The purpose of this paper is to report the results of using combined treatment of customized excimer laser-assisted photorefractive keratectomy (PRK) and prophylactic corneal collagen crosslinking (CXL) for residual refractive error in a group of patients who had previously undergone lamellar keratoplasty for keratoconus. The study included 14 eyes from 14 patients who had originally been treated for keratoconus in one eye by excimer laser-assisted lamellar keratoplasty (ELLK), and subsequently presented with residual ametropia (-6.11 D ± 2.48, range -2.50 to -9.50). After a mean 40.1 ± 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided transepithelial excimer laser PRK (central corneal regularization) and corneal CXL induced by riboflavin-ultraviolet A. After a mean 15 ± 6.5 (range 6-24) months, all eyes gained at least one Snellen line of uncorrected distance visual acuity (range 1-10). No patient lost lines of corrected distance visual acuity, and four patients gained three lines of corrected distance visual acuity. Mean manifest refractive spherical equivalent was -0.79 ± 2.09 (range +1 to -3.0) D, and topographic keratometric astigmatism was 5.02 ± 2.93 (range 0.8-8.9) D. All the corneas remained clear (haze PRK and corneal CXL provided safe and effective results in the management of corneal regularization for refractive purposes after ELLK for keratoconus.

  11. [E-PTFE Membrane for the Management of Perforated Corneal Ulcer].

    Pahor, D; Pahor, A

    2016-10-01

    Purpose: To present the surgical management of perforated corneal ulcer using PRECLUDE® Pericardial Membrane, composed of expanded polytetrafluoroethylene (e-PTFE; GORE-TEX®), as an alternative surgical procedure in patients at high risk of graft rejections and to evaluate side effects for a prolonged period. Patients and Methods: The study included all patients who were admitted to our department and underwent surgical repair of perforated corneal ulcer with the e-PTFE membrane between 2010 and 2015. In total, 8 patients (8 eyes) were enrolled. Medical records of all patients were retrospectively reviewed. The operation was performed under peribulbar anaesthesia. Non-absorbable, microporous, watertight 0.1 mm thick e-PTFE membrane was used to close the corneal ulcer. The membrane was cut to overlap the defect adequately and to achieve the desired tissue attachment without preparing the conjunctiva or superficial trephination of the cornea. The membrane was fixed to the healthy cornea with several non-absorbable sutures (Prolene® 10.0), in order to achieve the proper stress without wrinkling. Results: Five of 8 patients were treated for systemic immunological diseases. Sjögren's syndrome was diagnosed in 2 patients, granulomatosis with polyangiitis in one, vasculitis with a history of previous sclerokeratitis in one and systemic lupus erythematosus in one. In 2 patients, corneal perforation was observed as a complication of corneal infection and in one patient as a late complication of a severe chemical burn. Corneal perforations were successfully covered with e-PTFE membrane in all patients. E-PTFE membrane was well tolerated in all patients and the eye was always preserved. After 3 to 4 months, the membrane was removed in 7 patients. The underlying cornea was thin, firm, stable and vascularised. In one patient with Sjögren's syndrome, the e-PTFE membrane is still in place. Conclusion: Surgical management of perforated corneal ulcer using E-PTFE membrane

  12. Instillation of Sericin Enhances Corneal Wound Healing through the ERK Pathway in Rat Debrided Corneal Epithelium

    Noriaki Nagai

    2018-04-01

    Full Text Available Sericin is a major constituent of silk produced by silkworms. We previously found that the instillation of sericin enhanced the proliferation of corneal epithelial cells, and acted to promote corneal wound healing in both normal and diabetic model rats. However, the mechanisms by which sericin promotes the proliferation of corneal cells have not been established. In this study, we investigated the effects of sericin on Akt and ERK activation in a human corneal epithelial cell line (HCE-T cells and rat debrided corneal epithelium. Although Akt phosphorylation was not detected following the treatment of HCE-T cells with sericin, ERK1/2 phosphorylation was enhanced. The growth of HCE-T cells treated with sericin was significantly increased, with the cell growth of sericin-treated HCE-T cells being 1.7-fold higher in comparison with vehicle-treated HCE-T cells. On the other hand, both of an ERK inhibitor U0126 (non-specific specific inhibitor and SCH772984 (specific inhibitor attenuated the enhanced cell growth by sericin, and the growth level in the case of co-treatment with sericin and ERK1/2 inhibitor was similar to that of cells treated with ERK1/2 inhibitor alone. In an in vivo study using rat debrided corneal epithelium, the corneal wound healing rate was enhanced by the instillation of sericin, and this enhancement was also attenuated by the instillation of U0126. In addition, the corneal wound healing rate in rats co-instilled with sericin and U0126 was similar to that following the instillation of U0126 alone. In conclusion, we found that the instillation of sericin enhanced cell proliferation via the activation of the MAPK/ERK pathway, resulting in the promotion of corneal wound healing in rat eyes. These findings provide significant information for designing further studies to develop potent corneal wound-healing drugs.

  13. Development of a human corneal epithelium model utilizing a collagen vitrigel membrane and the changes of its barrier function induced by exposing eye irritant chemicals.

    Takezawa, Toshiaki; Nishikawa, Kazunori; Wang, Pi-Chao

    2011-09-01

    The brief TEER (trans-epithelial electrical resistance) assay after exposing chemicals to corneal epithelium in vivo is known as a suitable method for evaluating corneal irritancy and permeability quantitatively and continuously. A collagen vitrigel membrane we previously developed is a thin (about 20 μm thick) and transparent membrane composed of high density collagen fibrils equivalent to connective tissues in vivo, e.g. corneal Bowman's membrane. To develop such a TEER assay system in vitro utilizing a human corneal epithelial model, HCE-T cells (a human corneal epithelial cell line) were cultured on the collagen vitrigel membrane substratum prepared in a Millicell chamber suitable for TEER measurement. Human corneal epithelium model possessing 5-6 cell layers sufficient for TEER assay was successfully reconstructed on the substratum in the Millicell chamber by culturing the cells in monolayer for 2 days and subsequently in air-liquid interface for 7 days. The exposure of chemicals to the model induced the time-dependent relative changes of TEER in response to the characteristic of each chemical within a few minutes. These results suggest that the TEER assay using the human corneal epithelial model is very useful for an ocular irritancy evaluation as an alternative to the Draize eye irritation test. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Human tears reveal insights into corneal neovascularization.

    Zakaria, Nadia; Van Grasdorff, Sigi; Wouters, Kristien; Rozema, Jos; Koppen, Carina; Lion, Eva; Cools, Nathalie; Berneman, Zwi; Tassignon, Marie-José

    2012-01-01

    Corneal neovascularization results from the encroachment of blood vessels from the surrounding conjunctiva onto the normally avascular cornea. The aim of this study is to identify factors in human tears that are involved in development and/or maintenance of corneal neovascularization in humans. This could allow development of diagnostic tools for monitoring corneal neovascularization and combination monoclonal antibody therapies for its treatment. In an observational case-control study we enrolled a total of 12 patients with corneal neovascularization and 10 healthy volunteers. Basal tears along with reflex tears from the inferior fornix, superior fornix and using a corneal bath were collected along with blood serum samples. From all patients, ocular surface photographs were taken. Concentrations of the pro-angiogenic cytokines interleukin (IL)-6, IL-8, Vascular Endothelial Growth Factor (VEGF), Monocyte Chemoattractant Protein 1 (MCP-1) and Fas Ligand (FasL) were determined in blood and tear samples using a flow cytometric multiplex assay. Our results show that the concentration of pro-angiogenic cytokines in human tears are significantly higher compared to their concentrations in serum, with highest levels found in basal tears. Interestingly, we could detect a significantly higher concentration of IL- 6, IL-8 and VEGF in localized corneal tears of patients with neovascularized corneas when compared to the control group. This is the first study of its kind demonstrating a significant difference of defined factors in tears from patients with neovascularized corneas as compared to healthy controls. These results provide the basis for future research using animal models to further substantiate the role of these cytokines in the establishment and maintenance of corneal neovascularization.

  15. Longitudinal Evaluation of Wound Healing after Penetrating Corneal Injury: Anterior Segment Optical Coherence Tomography Study.

    Zheng, Kang Keng; Cai, Jianhao; Rong, Shi Song; Peng, Kun; Xia, Honghe; Jin, Chuan; Lu, Xuehui; Liu, Xinyu; Chen, Haoyu; Jhanji, Vishal

    2017-07-01

    Ocular imaging can enhance our understanding of wound healing. We report anterior segment optical coherence tomography (ASOCT) findings in penetrating corneal injury. Serial ASOCT was performed after repair of penetrating corneal injury. Internal aberrations of wound edges were labeled as "steps" or "gaps" on ASOCT images. The wound type was characterized as: type 1: continuous inner wound edge or step height ≤ 80 µm; type 2: step height > 80 µm; type 3: gap between wound edges; and type 4: intraocular tissue adherent to wound. Surgical outcomes of different wound types were compared. 50 consecutive patients were included (6 females, 44 males; mean age 33 ± 12 years). The average size of wound was 4.2 ± 2.6 mm (type 1, 8 eyes; type 2, 27 eyes; type 3, 12 eyes; type 4, 3 eyes). At the end of 3 months, 70% (n = 35) of the wounds were type 1. At the end of 6 months, all type 1 wounds had healed completely, whereas about half of type 2 (48.1%) and type 3 (50%) wounds had recovered to type 1 configuration. The wound type at baseline affected the height of step (p = 0.047) and corneal thickness at 6 months (p = 0.035). ASOCT is a useful tool for monitoring wound healing in cases with penetrating corneal injury. Majority of the wound edges appose between 3 and 6 months after trauma. In our study, baseline wound configuration affected the healing pattern.

  16. Role of Decorin Core Protein in Collagen Organisation in Congenital Stromal Corneal Dystrophy (CSCD.

    Christina S Kamma-Lorger

    Full Text Available The role of Decorin in organising the extracellular matrix was examined in normal human corneas and in corneas from patients with Congenital Stromal Corneal Dystrophy (CSCD. In CSCD, corneal clouding occurs due to a truncating mutation (c.967delT in the decorin (DCN gene. Normal human Decorin protein and the truncated one were reconstructed in silico using homology modelling techniques to explore structural changes in the diseased protein. Corneal CSCD specimens were also examined using 3-D electron tomography and Small Angle X-ray diffraction (SAXS, to image the collagen-proteoglycan arrangement and to quantify fibrillar diameters, respectively. Homology modelling showed that truncated Decorin had a different spatial geometry to the normal one, with the truncation removing a major part of the site that interacts with collagen, compromising its ability to bind effectively. Electron tomography showed regions of abnormal stroma, where collagen fibrils came together to form thicker fibrillar structures, showing that Decorin plays a key role in the maintenance of the order in the normal corneal extracellular matrix. Average diameter of individual fibrils throughout the thickness of the cornea however remained normal.

  17. Comparison of the effects of intraocular irrigating solutions on the corneal endothelium in intraocular lens implantation.

    Matsuda, M; Kinoshita, S; Ohashi, Y; Shimomura, Y; Ohguro, N; Okamoto, H; Omoto, T; Hosotani, H; Yoshida, H

    1991-01-01

    We conducted a randomised prospective controlled study to determine the effects of a glucose glutathione bicarbonate solution (BSS Plus) and a citrate acetate bicarbonate solution (S-MA2) on the corneal endothelium in patients undergoing extracapsular cataract extraction with posterior chamber lens implantation. One eye of each patient was randomly assigned to receive BSS Plus, and the other eye to receive S-MA2. BSS Plus caused significantly less corneal swelling on the first postoperative day than did S-MA2. There was no difference between the two solutions in their effect on corneal thickness one week and one month postoperatively. Computer assisted morphometric analysis of wide-field specular microscopic photographs demonstrated minimal changes in endothelial morphological characteristics in the eyes irrigated with BSS Plus. By comparison S-MA2, caused a significant loss of endothelial cells and a marked reduction in the figure coefficient. These results indicated that BSS Plus has a clinical advantage over S-MA2 with respect to the corneal endothelium. PMID:1873266

  18. Prevalence and causes of corneal blindness.

    Wang, Haijing; Zhang, Yaoguang; Li, Zhijian; Wang, Tiebin; Liu, Ping

    2014-04-01

    The study aimed to assess the prevalence and causes of corneal blindness in a rural northern Chinese population. Cross-sectional study. The cluster random sampling method was used to select the sample. This population-based study included 11 787 participants of all ages in rural Heilongjiang Province, China. These participants underwent a detailed interview and eye examination that included the measurement of visual acuity, slit-lamp biomicroscopy and direct ophthalmoscopy. An eye was considered to have corneal blindness if the visual acuity was blindness and low vision. Among the 10 384 people enrolled in the study, the prevalence of corneal blindness is 0.3% (95% confidence interval 0.2-0.4%). The leading cause was keratitis in childhood (40.0%), followed by ocular trauma (33.3%) and keratitis in adulthood (20.0%). Age and illiteracy were found to be associated with an increased prevalence of corneal blindness. Blindness because of corneal diseases in rural areas of Northern China is a significant public health problem that needs to be given more attention. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  19. Contact lens rehabilitation following repaired corneal perforations

    Titiyal, Jeewan S; Sinha, Rajesh; Sharma, Namrata; Sreenivas, V; Vajpayee, Rasik B

    2006-01-01

    Background Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. Method Eyes that had undergone repair for corneal perforating injuries with or without lens aspiration were fitted rigid gas permeable contact lenses. The fitting pattern and the improvement in visual acuity by contact lens over spectacle correction were noted. Results Forty eyes of 40 patients that had undergone surgical repair of posttraumatic corneal perforations were fitted rigid gas permeable contact lenses for visual rehabilitation. Twenty-four eyes (60%) required aphakic contact lenses. The best corrected visual acuity (BCVA) of ≥ 6/18 in the snellen's acuity chart was seen in 10 (25%) eyes with spectacle correction and 37 (92.5%) eyes with the use of contact lens (p < 0.001). The best-corrected visual acuity with spectacles was 0.20 ± 0.13 while the same with contact lens was 0.58 ± 0.26. All the patients showed an improvement of ≥ 2 lines over spectacles in the snellen's acuity chart with contact lens. Conclusion Rigid gas permeable contact lenses are better means of rehabilitation in eyes that have an irregular cornea due to scars caused by perforating corneal injuries. PMID:16536877

  20. Efficacy of Tectonic Corneal Patch Graft for Progressive Peripheral Corneal Thinning

    Cafer Tanrıverdio

    2014-12-01

    Full Text Available Objectives: To report the results of tectonic corneal patch graft (TCPG in patients with progressive peripheral corneal thinning (PCT. Materials and Methods: In this study, we included 8 patients who underwent TCPG for PCT or perforated corneal ulceration at Ankara Training and Research Hospital. Results: We performed TCPG in 7 patients for PCT and in 1 patient for perforated corneal ulceration. Mean age was 57.2±16.7 (38- 82 years. Postoperative follow-up time ranged from 6 to 24 months (mean 13.9±6.7. Possible etiologies leading to progressive PCT were trachoma, infectious corneal ulcer, and rheumatoid arthritis-severe dry eye in 2 patients each. Other 2 patients had a progressive PCT following ocular surgery. One of the patients with infectious corneal ulcer also had a trauma caused by a scissor. Amnion membrane transplantation was performed in 3 patients prior to TCPG. While the anatomic success was achieved in all 8 patients, best-corrected visual acuity (BCVA was 0.1 or better in 4 patients (50%. Postoperative BCVA was better than preoperative BCVA in 6 patients (75%. Local peripheral anterior synechiae developed in two eyes. Conclusion: TCPG is a useful therapeutic option in selected cases of corneal thinning and perforations because it effectively restores the integrity of the globe and allows acceptable visual results. (Turk J Ophthalmol 2014; 44: 440-4

  1. Keratocyte apoptosis and corneal antioxidant enzyme activities after refractive corneal surgery.

    Bilgihan, K; Bilgihan, A; Adiguzel, U; Sezer, C; Yis, O; Akyol, G; Hasanreisoglu, B

    2002-01-01

    Refractive corneal surgery induces keratocyte apoptosis and generates reactive oxygen radicals (ROS) in the cornea. The purpose of the present study is to evaluate the correlation between keratocyte apoptosis and corneal antioxidant enzyme activities after different refractive surgical procedures in rabbits. Rabbits were divided into six groups. All groups were compared with the control group (Group 1), after epithelial scraping (Group 2), epithelial scrape and photorefractive keratectomy (PRK) (traditional PRK: Group 3), transepithelial PRK (Group 4), creation of a corneal flap with microkeratome (Group 5) and laser-assisted in situ keratomileusis (LASIK, Group 6). Terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling assay (to detect DNA fragmentation in situ) and light microscopy were used to detect apoptosis in rabbit eyes. Glutathione peroxidase (Gpx) and superoxide dismutase (SOD) activities of the corneal tissues were measured with spectrophotometric methods. Corneal Gpx and SOD activities decreased significantly in all groups when compared with the control group (P<0.05) and groups 2, 3 and 6 showed a significantly higher amount of keratocyte apoptosis (P<0.05). Not only a negative correlation was observed between corneal SOD activity and keratocyte apoptosis (cc: -0.3648) but Gpx activity also showed negative correlation with keratocyte apoptosis (cc: -0.3587). The present study illustrates the negative correlation between keratocyte apoptosis and corneal antioxidant enzyme activities. This finding suggests that ROS may be partly responsible for keratocyte apoptosis after refractive surgery.

  2. The effect of Gonioscopy on keratometry and corneal surface topography

    DeBroff Brian M

    2006-06-01

    . Conclusion Reversible steepening of the central corneal surface is produced by the act of gonioscopy as measured by Sim K, whereas no significant differences were present with Auto-K measurements. The type of Gonioscope used does not appear to influence these results. If topographically derived Sim K is used to calculate the power of the intraocular lens implant, we recommend waiting a minimum of 20 minutes before measuring the corneal curvature after gonioscopy with either Goldmann or Sussman contact lenses.

  3. The effect of Gonioscopy on keratometry and corneal surface topography.

    George, Mathew K; Kuriakose, Thomas; DeBroff, Brian M; Emerson, John W

    2006-06-17

    Biometric procedures such as keratometry performed shortly after contact procedures like gonioscopy and applanation tonometry could affect the validity of the measurement. This study was conducted to understand the short-term effect of gonioscopy on corneal curvature measurements and surface topography based Simulated Keratometry and whether this would alter the power of an intraocular lens implant calculated using post-gonioscopy measurements. We further compared the effect of the 2-mirror (Goldmann) and the 4-mirror (Sussman) Gonioscopes. A prospective clinic-based self-controlled comparative study. 198 eyes of 99 patients, above 50 years of age, were studied. Exclusion criteria included documented dry eye, history of ocular surgery or trauma, diabetes mellitus and connective tissue disorders. Auto-Keratometry and corneal topography measurements were obtained at baseline and at three follow-up times - within the first 5 minutes, between the 10th-15th minute and between the 20th-25th minute after intervention. One eye was randomized for intervention with the 2-mirror gonioscope and the other underwent the 4-mirror after baseline measurements. t-tests were used to examine differences between interventions and between the measurement methods. The sample size was calculated using an estimate of clinically significant lens implant power changes based on the SRK-II formula. Clinically and statistically significant steepening was observed in the first 5 minutes and in the 10-15 minute interval using topography-based Sim K. These changes were not present with the Auto-Keratometer measurements. Although changes from baseline were noted between 20 and 25 minutes topographically, these were not clinically or statistically significant. There was no significant difference between the two types of gonioscopes. There was greater variability in the changes from baseline using the topography-based Sim K readings. Reversible steepening of the central corneal surface is produced by

  4. Stromal demarcation line induced by corneal cross-linking in eyes with keratoconus and nonkeratoconic asymmetric topography.

    Malta, João B N; Renesto, Adimara C; Moscovici, Bernardo K; Soong, H K; Campos, Mauro

    2015-02-01

    To evaluate stromal demarcation lines following corneal cross-linking (CXL) using anterior segment optical coherence tomography in patients with keratoconus and nonkeratoconic asymmetric topography. Fifth-nine eyes of 59 patients were enrolled in a retrospective comparative case series, of which 19 eyes had keratoconus and 40 eyes had asymmetric topography. Eyes with asymmetric topography were treated in preparation for photorefractive keratectomy. One month after CXL, a stromal demarcation line was evaluated at 5 standardized corneal points using anterior segment optical coherence tomography. Mean stromal demarcation line depths were measured at 5 points on the cornea, namely, centrally, 3.0 mm temporally, 1.5 mm temporally, 3.0 mm nasally, and 1.5 mm nasally. For the keratoconus group, the values were 178 ± 47, 123 ± 15, 152 ± 47, 125 ± 23, and 160 ± 43 μm, respectively. For the asymmetric corneal topography group (without keratoconus), they were 305 ± 64, 235 ± 57, 294 ± 50, 214 ± 54, and 285 ± 58 μm, respectively. There was no correlation between central corneal pachymetry and stromal demarcation line depth in all 5 measured corneal points in both groups. CXL treatment profiles are similar in keratoconic and nonkeratoconic eyes with asymmetric topography.

  5. Evaluation of corneal higher order aberrations in normal topographic patterns

    Ali Mirzajani

    2016-06-01

    Conclusions: Based on results in this study, there were a good correlation between corneal topographic pattern and corneal HOAs in normal eyes. These results indicate that the corneal HOAs values are largely determined by the topographic patterns. A larger sample size would perhaps have been beneficial to yield in more accurate outcomes.

  6. Clinical Validation of Point-Source Corneal Topography in Keratoplasty

    Vrijling, A C L; Braaf, B.; Snellenburg, J.J.; de Lange, F.; Zaal, M.J.W.; van der Heijde, G.L.; Sicam, V.A.D.P.

    2011-01-01

    Purpose. To validate the clinical performance of point-source corneal topography (PCT) in postpenetrating keratoplasty (PKP) eyes and to compare it with conventional Placido-based topography. Methods. Corneal elevation maps of the anterior corneal surface were obtained from 20 post-PKP corneas using

  7. Corneal surface temperature change as the mode of stimulation of the non-contact corneal aesthesiometer.

    Murphy, P J; Morgan, P B; Patel, S; Marshall, J

    1999-05-01

    The non-contact corneal aesthesiometer (NCCA) assesses corneal sensitivity by using a controlled pulse of air, directed at the corneal surface. The purpose of this paper was to investigate whether corneal surface temperature change was a component in the mode of stimulation. Thermocouple experiment: A simple model corneal surface was developed that was composed of a moistened circle of filter paper placed on a thermocouple and mounted on a glass slide. The temperature change produced by different stimulus pressures was measured for five different ambient temperatures. Thermal camera experiment: Using a thermal camera, the corneal surface temperature change was measured in nine young, healthy subjects after exposure to different stimulus air pulses. Pulse duration was set at 0.9 s but was varied in pressure from 0.5 to 3.5 millibars. Thermocouple experiment: An immediate drop in temperature was detected by the thermocouple as soon as the air flow was incident on the filter paper. A greater temperature change was produced by increasing the pressure of the incident air flow. A relationship was found and a calibration curve plotted. Thermal camera experiment: For each subject, a drop in surface temperature was detected at each stimulus pressure. Furthermore, as the stimulus pressure increased, the induced reduction in temperature also increased. A relationship was found and a calibration curve plotted. The NCCA air-pulse stimulus was capable of producing a localized temperature change on the corneal surface. The principal mode of corneal nerve stimulation, by the NCCA air pulse, was the rate of temperature change of the corneal surface.

  8. The SULFs, extracellular sulfatases for heparan sulfate, promote the migration of corneal epithelial cells during wound repair.

    Inna Maltseva

    Full Text Available Corneal epithelial wound repair involves the migration of epithelial cells to cover the defect followed by the proliferation of the cells to restore thickness. Heparan sulfate proteoglycans (HSPGs are ubiquitous extracellular molecules that bind to a plethora of growth factors, cytokines, and morphogens and thereby regulate their signaling functions. Ligand binding by HS chains depends on the pattern of four sulfation modifications, one of which is 6-O-sulfation of glucosamine (6OS. SULF1 and SULF2 are highly homologous, extracellular endosulfatases, which post-synthetically edit the sulfation status of HS by removing 6OS from intact chains. The SULFs thereby modulate multiple signaling pathways including the augmentation of Wnt/ß-catenin signaling. We found that wounding of mouse corneal epithelium stimulated SULF1 expression in superficial epithelial cells proximal to the wound edge. Sulf1⁻/⁻, but not Sulf2⁻/⁻, mice, exhibited a marked delay in healing. Furthermore, corneal epithelial cells derived from Sulf1⁻/⁻ mice exhibited a reduced rate of migration in repair of a scratched monolayer compared to wild-type cells. In contrast, human primary corneal epithelial cells expressed SULF2, as did a human corneal epithelial cell line (THCE. Knockdown of SULF2 in THCE cells also slowed migration, which was restored by overexpression of either mouse SULF2 or human SULF1. The interchangeability of the two SULFs establishes their capacity for functional redundancy. Knockdown of SULF2 decreased Wnt/ß-catenin signaling in THCE cells. Extracellular antagonists of Wnt signaling reduced migration of THCE cells. However in SULF2- knockdown cells, these antagonists exerted no further effects on migration, consistent with the SULF functioning as an upstream regulator of Wnt signaling. Further understanding of the mechanistic action of the SULFs in promoting corneal repair may lead to new therapeutic approaches for the treatment of corneal injuries.

  9. Resolvin D1 promotes corneal epithelial wound healing and restoration of mechanical sensation in diabetic mice.

    Zhang, Zhenzhen; Hu, Xiaoli; Qi, Xia; Di, Guohu; Zhang, Yangyang; Wang, Qian; Zhou, Qingjun

    2018-01-01

    To investigate the effect and mechanism of proresolving lipid mediator resolvin D1 (RvD1) on the corneal epithelium and the restoration of mechanical sensation in diabetic mice. Type 1 diabetes was induced in mice with intraperitoneal streptozocin injections. The healthy and diabetic mice underwent removal of the central corneal epithelium, and then 100 ng/ml RvD1 or its formyl peptide receptor 2 (FPR2) antagonist WRW4 was used to treat the diabetic mice. Regeneration of the corneal epithelium and nerves was observed with sodium fluorescein staining and whole-mount anti-β3-tubulin fluorescence staining. The inflammatory response level was measured with hematoxylin and eosin staining (inflammatory cell infiltration), enzyme-linked immunosorbent assay (tumor necrosis factor alpha and interleukin-1 beta content), myeloperoxidase activity, and fluorescence staining (macrophage content). The reactive oxygen species (ROS) and glutathione (GSH) levels were examined with incubation with fluorescent probes, and oxidative stress-related protein expression levels were evaluated with fluorescence staining and western blotting. Topical application of RvD1 promoted regeneration of the corneal epithelium in diabetic mice, accompanied by the reactivation of signaling and inflammation resolution related to regeneration of the epithelium. Furthermore, RvD1 directly attenuated the accumulation of ROS and nicotinamide adenine dinucleotide phosphate oxidase 2/4 expression, while RvD1 enhanced GSH synthesis and reactivated the Nrf2-ARE signaling pathway that was impaired in the corneal epithelium in the diabetic mice. More interestingly, topical application of RvD1 promoted regeneration of corneal nerves and completely restored impaired mechanical sensitivity of the cornea in diabetic mice. In addition, the promotion of corneal epithelial wound healing by RvD1 in diabetic mice was abolished by its FPR2 antagonist WRW4. Topical application of RvD1 promotes corneal epithelial wound

  10. Mechanisms of allograft rejection of corneal endothelium

    Tagawa, Y.; Silverstein, A.M.; Prendergast, R.A.

    1982-01-01

    The local intraocular graft-vs.-host (GVH) reaction, involving the destruction of the corneal endothelial cells of the rabbit host by sensitized donor lymphoid cells, has been used to study the mechanism of corneal allograft rejection. Pretreatment of donor cells with a specific mouse monoclonal hybridoma anti-T cell antibody and complement suppresses the destructive reaction, suggesting that a cellular-immune mechanism is primarily involved. Pretreatment of donor cells with mitomycin-C completely abolishes the local GVH reaction, indicating that the effector lymphocytes must undergo mitosis within the eye before they can engage in target cell destruction. Finally, studies of the local GVH reaction in irradiated leukopenic recipients or in preinflamed rabbit eyes suggest that host leukocytes may contribute nonspecifically to enhance the destructive process. These studies show that the local ocular GVH reaction may provide a useful model for the study of the mechanisms involved in the rejection of corneal allografts

  11. Applications of biomaterials in corneal wound healing

    I-Lun Tsai

    2015-04-01

    Full Text Available Disease affecting the cornea is a common cause of blindness worldwide. To date, the amniotic membrane (AM is the most widely used clinical method for cornea regeneration. However, donor-dependent differences in the AM may result in variable clinical outcomes. To overcome this issue, biomaterials are currently under investigation for corneal regeneration in vitro and in vivo. In this article, we highlight the recent advances in hydrogels, bioengineered prosthetic devices, contact lenses, and drug delivery systems for corneal regeneration. In clinical studies, the therapeutic effects of biomaterials, including fibrin and collagen-based hydrogels and silicone contact lenses, have been demonstrated in damaged cornea. The combination of cells and biomaterials may provide potential treatment in corneal wound healing in the future.

  12. Regulation of corneal stroma extracellular matrix assembly.

    Chen, Shoujun; Mienaltowski, Michael J; Birk, David E

    2015-04-01

    The transparent cornea is the major refractive element of the eye. A finely controlled assembly of the stromal extracellular matrix is critical to corneal function, as well as in establishing the appropriate mechanical stability required to maintain corneal shape and curvature. In the stroma, homogeneous, small diameter collagen fibrils, regularly packed with a highly ordered hierarchical organization, are essential for function. This review focuses on corneal stroma assembly and the regulation of collagen fibrillogenesis. Corneal collagen fibrillogenesis involves multiple molecules interacting in sequential steps, as well as interactions between keratocytes and stroma matrix components. The stroma has the highest collagen V:I ratio in the body. Collagen V regulates the nucleation of protofibril assembly, thus controlling the number of fibrils and assembly of smaller diameter fibrils in the stroma. The corneal stroma is also enriched in small leucine-rich proteoglycans (SLRPs) that cooperate in a temporal and spatial manner to regulate linear and lateral collagen fibril growth. In addition, the fibril-associated collagens (FACITs) such as collagen XII and collagen XIV have roles in the regulation of fibril packing and inter-lamellar interactions. A communicating keratocyte network contributes to the overall and long-range regulation of stromal extracellular matrix assembly, by creating micro-domains where the sequential steps in stromal matrix assembly are controlled. Keratocytes control the synthesis of extracellular matrix components, which interact with the keratocytes dynamically to coordinate the regulatory steps into a cohesive process. Mutations or deficiencies in stromal regulatory molecules result in altered interactions and deficiencies in both transparency and refraction, leading to corneal stroma pathobiology such as stromal dystrophies, cornea plana and keratoconus. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Dextran Preserves Native Corneal Structure During Decellularization.

    Lynch, Amy P; Wilson, Samantha L; Ahearne, Mark

    2016-06-01

    Corneal decellularization has become an increasingly popular technique for generating scaffolds for corneal regeneration. Most decellularization procedures result in tissue swelling, thus limiting their application. Here, the use of a polysaccharide, dextran, to reduce swelling and conserve the native corneal structure during decellularization was investigated. Corneas were treated with 1% Triton X-100, 0.5% sodium dodecyl sulfate, and nucleases under constant rotation followed by extensive washing. To reduce swelling, decellularization solutions were supplemented with 5% dextran either throughout the whole decellularization process or during the washing cycles only. Quantitative analysis of DNA content showed a 96% reduction after decellularization regardless of the addition of dextran. Dextran resulted in a significant reduction in swelling from 3.85 ± 0.43 nm without to 1.94 ± 0.29-2.01 ± 0.37 nm (p dextran must be present throughout the decellularization protocol to preserve the native corneal architecture, anisotropy analysis demonstrated comparable results (0.22 ± 0.03) to the native cornea (0.24 ± 0.02), p > 0.05. Dextran can counteract the detrimental effects of decellularizing agents on the biomechanical properties of the tissue resulting in similar compressive moduli (mean before decellularization: 5.40 ± 1.18 kPa; mean after decellularization with dextran: 5.64 ± 1.34 kPa, p > 0.05). Cells remained viable in the presence of decellularized scaffolds. The findings of this study indicate that dextran not only prevents significant corneal swelling during decellularization but also enhances the maintenance of the native corneal ultrastructure.

  14. Host immune cellular reactions in corneal neovascularization

    Nizar S. Abdelfattah

    2016-04-01

    Full Text Available Corneal neovascularization (CNV is a global important cause of visual impairment. The immune mechanisms leading to corneal heme- and lymphangiogenesis have been extensively studied over the past years as more attempts were made to develop better prophylactic and therapeutic measures. This article aims to discuss immune cells of particular relevance to CNV, with a focus on macrophages, Th17 cells, dendritic cells and the underlying immunology of common pathologies involving neovascularization of the cornea. Hopefully, a thorough understanding of these topics would propel the efforts to halt the detrimental effects of CNV.

  15. Corneal collagen crosslinking for keratoconus. A review

    M. M. Bikbov

    2014-10-01

    Full Text Available Photochemical crosslinking is widely applied in ophthalmology. Its biochemical effect is due to the release of singlet oxygen that promotes anaerobic photochemical reaction. Keratoconus is one of the most common corneal ectasia affecting 1 in 250 to 250 000 persons. Currently, the rate of iatrogenic ectasia following eximer laser refractive surgery increases due to biomechanical weakening of the cornea. Morphologically and biochemically, ectasia is characterized by corneal layers thinning, contact between the stroma and epithelium resulting from Bowman’s membrane rupture, chromatin fragmentation in keratocyte nuclei, phagocytosis, abnormal staining and arrangement of collagen fibers, enzyme system disorders, and keratocyte apoptosis. In corneal ectasia, altered enzymatic processes result in the synthesis of abnormal collagen. Collagen packing is determined by the activity of various extracellular matrix enzymes which bind amines and aldehydes of collagen fiber amino acids. In the late stage, morphological changes of Descemet’s membrane (i.e., rupture and detachment develop. Abnormal hexagonal-shaped keratocytes and their apoptosis are the signs of endothelial dystrophy. The lack of analogs in domestic ophthalmology encouraged the scientists of Ufa Eye Research Institute to develop a device for corneal collagen crosslinking. The parameters of ultraviolet (i.e., wavelength, exposure time, power to achieve the desired effect were identified. The specifics of some photosensitizers in the course of the procedure were studied. UFalink, a device for UV irradiation of cornea, and photosensitizer Dextralink were developed and adopted. Due to the high risk of endothelial damage, this treatment is contraindicated in severe keratoconus (CCT less than 400 microns. Major effects of corneal collagen crosslinking are the following: Young’s modulus (modulus of elasticity increase by 328.9 % (on average, temperature tolerance increase by 5

  16. Research on inhibition of corneal neovascularization

    Zhang-Hui Yang

    2015-12-01

    Full Text Available Corneal transparency is the basis of the normal physiological functions.However, corneal neovascularization(CNVmay occur in the infection, mechanical and chemical injury or under other pathological conditions,which make the cornea lose original transparency and severe visual impairment. In recent years, along with the development of immunology, molecular biology, biochemistry and other disciplines, there is more in-depth understanding on the CNV, and clinical treatment of CNV has made new breakthroughs. This article provides an overview of the inhibition of CNV.

  17. A Comparison of Different Corneal Iontophoresis Protocols for Promoting Transepithelial Riboflavin Penetration.

    Gore, Daniel M; O'Brart, David P; French, Paul; Dunsby, Chris; Allan, Bruce D

    2015-12-01

    To measure corneal riboflavin penetration using different transepithelial iontophoresis protocols. Freshly enucleated rabbit eyes were divided into nine treatment groups of 4 eyes. One group, in which 0.1% wt/vol riboflavin was applied for 30 minutes without iontophoresis after corneal epithelial debridement, acted as a control. The remaining groups were treated with an intact epithelium using different riboflavin formulations and varying iontophoresis current, soak, and rinse times. After riboflavin application, eyes were snap frozen in liquid nitrogen. Corneal cross sections 35 μm thick were then imaged immediately by two-photon fluorescence microscopy, using image processing software to quantify stromal riboflavin concentration at different corneal depths. In the epithelium-on iontophoresis treatment groups, greater stromal riboflavin penetration was achieved with higher-concentration riboflavin solutions, greater iontophoresis dosage, and longer solution contact times. A protocol utilizing 0.25% wt/vol riboflavin with benzalkonium chloride (BAC) 0.01% and two cycles of applied current and subsequent soaking (1 mA 5 minutes, soak 5 minutes; 0.5 mA 5 minutes, soak 5 minutes) achieved similar stromal riboflavin penetration to epithelium-off controls. The best-performing non-BAC-containing protocol produced stromal riboflavin penetration approximately 60% that of epithelium-off controls. Riboflavin solutions containing saline resulted in minimal stromal penetration. Riboflavin loading within the epithelium was equivalent to or higher than that in the subjacent stroma, despite rinsing the ocular surface with balanced salt solution. Modified iontophoresis protocols can significantly improve transepithelial riboflavin penetration in experimental corneal collagen cross-linking.

  18. Variable corneal compensation improves discrimination between normal and glaucomatous eyes with the scanning laser polarimeter.

    Tannenbaum, Dana P; Hoffman, Douglas; Lemij, Hans G; Garway-Heath, David F; Greenfield, David S; Caprioli, Joseph

    2004-02-01

    The presently available scanning laser polarimeter (SLP) has a fixed corneal compensator (FCC) that neutralizes corneal birefringence only in eyes with birefringence that matches the population mode. A prototype variable corneal compensator (VCC) provides neutralization of individual corneal birefringence based on individual macular retardation patterns. The aim of this study was to evaluate the relative ability of the SLP with the FCC and with the VCC to discriminate between normal and glaucomatous eyes. Prospective, nonrandomized, comparative case series. Algorithm-generating set consisting of 56 normal eyes and 55 glaucomatous eyes and an independent data set consisting of 83 normal eyes and 56 glaucomatous eyes. Sixteen retardation measurements were obtained with the SLP with the FCC and the VCC from all subjects. Dependency of parameters on age, gender, ethnic origin, and eye side was sought. Logistic regression was used to evaluate how well the various parameters could detect glaucoma. Discriminant functions were generated, and the area under the receiver operating characteristic (ROC) curve was determined. Discrimination between normal and glaucomatous eyes on the basis of single parameters was significantly better with the VCC than with the FCC for 6 retardation parameters: nasal average (P = 0.0003), superior maximum (P = 0.0003), ellipse average (P = 0.002), average thickness (P = 0.003), superior average (P = 0.010), and inferior average (P = 0.010). Discriminant analysis identified the optimal combination of parameters for the FCC and for the VCC. When the discriminant functions were applied to the independent data set, areas under the ROC curve were 0.84 for the FCC and 0.90 for the VCC (PFCC and 0.90 for the VCC (P<0.016). Individual correction for corneal birefringence with the VCC significantly improved the ability of the SLP to distinguish between normal and glaucomatous eyes and enabled detection of patients with early glaucoma.

  19. Derivation of corneal endothelial cell-like cells from rat neural crest cells in vitro.

    Chengqun Ju

    Full Text Available The aim of this study was to investigate the feasibility of inducing rat neural crest cells (NCC to differentiate to functional corneal endothelial cell (CEC-like cells in vitro. Rat NCC were induced with adult CEC-derived conditioned medium. Immunofluorescence, flow cytometry and real time RT-PCR assay were used to detect expression of the corneal endothelium differentiation marker N-cadherin and transcription factors FoxC1 and Pitx2. CFDA SE-labeled CEC-like cells were transplanted to the corneal endothelium of a rat corneal endothelium deficiency model, and an eye-down position was maintained for 24 hours to allow cell attachment. The animals were observed for as long as 2 months after surgery and underwent clinical and histological examination. Spindle-like NCC turned to polygonal CEC-like after induction and expressed N-cadherin, FoxC1, Pitx2, zonula occludens-1 and sodium-potassium pump Na(+/K(+ ATPase. The corneas of the experimental group were much clearer than those of the control group and the mean corneal thickness in the experimental group was significantly less than in the control group7, 14, 21 and 28 days after surgery. Confocal microscopy through focusing and histological analysis confirmed that green fluorescence-positive CEC-like cells formed a monolayer covering the Descemet's membrane in the experimental group. In conclusion, CEC-like cells derived from NCCs displayed characters of native CEC, and the induction protocol provides guidance for future human CEC induction from NCC.

  20. Management of corneal ectasia after LASIK with combined, same-day, topography-guided partial transepithelial PRK and collagen cross-linking: the athens protocol.

    Kanellopoulos, Anastasios John; Binder, Perry S

    2011-05-01

    To evaluate a series of patients with corneal ectasia after LASIK that underwent the Athens Protocol: combined topography-guided photorefractive keratectomy (PRK) to reduce or eliminate induced myopia and astigmatism followed by sequential, same-day ultraviolet A (UVA) corneal collagen cross-linking (CXL). Thirty-two consecutive corneal ectasia cases underwent transepithelial PRK (WaveLight ALLEGRETTO) immediately followed by CXL (3 mW/cm(2)) for 30 minutes using 0.1% topical riboflavin sodium phosphate. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, keratometry, central ultrasonic pachymetry, corneal tomography (Oculus Pentacam), and endothelial cell counts were analyzed. Mean follow-up was 27 months (range: 6 to 59 months). Twenty-seven of 32 eyes had an improvement in UDVA and CDVA of 20/45 or better (2.25 logMAR) at last follow-up. Four eyes showed some topographic improvement but no improvement in CDVA. One of the treated eyes required a subsequent penetrating keratoplasty. Corneal haze grade 2 was present in 2 eyes. Combined, same-day, topography-guided PRK and CXL appeared to offer tomographic stability, even after long-term follow-up. Only 2 of 32 eyes had corneal ectasia progression after the intervention. Seventeen of 32 eyes appeared to have improvement in UDVA and CDVA with follow-up >1.5 years. This technique may offer an alternative in the management of iatrogenic corneal ectasia. Copyright 2011, SLACK Incorporated.

  1. Microscopia confocal en cirugía refractiva corneal: ¿útil o imprescindible?

    Eduardo Rojas Álvarez

    Full Text Available Introducción: el estudio morfométrico de la córnea con posterioridad a la cirugía refractiva corneal con Láser Excímer, se ha convertido, en los últimos años, en tema de investigación recurrente a nivel internacional, con vistas a obtener resultados in vivo del tejido corneal y por tanto, evaluar estas novedosas tecnologías. Objetivo: describir las aplicaciones de la microscopia confocal de la córnea en cirugía refractiva con Láser Excímer. Método: se realizó un estudio exploratorio del tema, teniendo en cuenta las publicaciones de los últimos 5 años de los autores más representativos, así como las revistas de mayor impacto de la especialidad. Se utilizó la plataforma Infomed, específicamente la Biblioteca Virtual de Salud (Ebsco,Hinari, PERii, SciELO Cuba, SciELO regional, PLoS Medicine, Pubmed Central, Biomed Central, DOAJ, Free Medical Journals. La información fue resumida para la elaboración del informe final. Resultados: se han obtenido en diferentes estudios valores de densidad corneal por subcapas, grosores corneales, características de células y nervios corneales, evolución en el tiempo de estos cambios y relaciones estadísticas entre variables morfométricas. Conclusiones: el oftalmólogo dedicado a cirugía refractiva corneal debe dominar e incorporar a su práctica cotidiana la microscopia confocal corneal como una herramienta pre y posoperatoria que ya se ha hecho imprescindible en vistas a elevar la seguridad de este tipo de tratamiento. No todo está dicho, la línea investigativa del tema apunta a un mayor desarrollo en los años venideros que tiene como atenuante la poca accesibilidad a este proceder en otros países por su elevado costo.

  2. New Details of the Human Corneal Limbus Revealed With Second Harmonic Generation Imaging.

    Park, Choul Yong; Lee, Jimmy K; Zhang, Cheng; Chuck, Roy S

    2015-09-01

    To report novel findings of the human corneal limbus by using second harmonic generation (SHG) imaging. Corneal limbus was imaged by using an inverted two-photon excitation fluorescence microscope. Laser (Ti:Sapphire) was tuned at 850 nm for two-photon excitation. Backscatter signals of SHG and autofluorescence (AF) were collected through a 425/30-nm emission filter and a 525/45-emission filter, respectively. Multiple, consecutive, and overlapping image stacks (z-stack) were acquired for the corneal limbal area. Two novel collagen structures were revealed by SHG imaging at the limbus: an anterior limbal cribriform layer and presumed anchoring fibers. Anterior limbal cribriform layer is an intertwined reticular collagen architecture just beneath the limbal epithelial niche and is located between the peripheral cornea and Tenon's/scleral tissue. Autofluorescence imaging revealed high vascularity in this structure. Central to the anterior limbal cribriform layer, radial strands of collagen were found to connect the peripheral cornea to the limbus. These presumed anchoring fibers have both collagen and elastin and were found more extensively in the superficial layers than deep layer and were absent in very deep limbus near Schlemm's canal. By using SHG imaging, new details of the collagen architecture of human corneal limbal area were elucidated. High resolution images with volumetric analysis revealed two novel collagen structures.

  3. Corneal clarity measurements in healthy volunteers across different age groups: Observational study.

    Alzahrani, Khaled; Carley, Fiona; Brahma, Arun; Morley, Debbie; Hillarby, M Chantal

    2017-11-01

    The aim of this study was to standardize and investigate the changes in corneal clarity with age. Densitometry software for the Oculus Pentacam was used to examine corneal clarity at different age groups.A total of 192 eyes from 97 healthy participants were included in this cohort comparative nonrandomized, cross-sectional study. An Oculus Pentcam was used to image the cornea of healthy participants grouped by age (between 10 and 70 years old). Data from the densitometry output have been used to determine clarity in concentric zones and different depths of the cornea.Corneal densitometry (CD) across all ages showed significant differences between groups when divided into the following layers: anterior, central, and posterior or divided into 0 to 2, 2 to 6, and 6 to 10 mm concentric zones (P age in all 3 layers of the periphery (6-10 mm) (P age group had lower clarity than the 20 to 30-age group (P age is differed when the cornea is divided into layers and zones. This study suggests that there are other factors that may play an essential role in corneal clarity as well as age.

  4. Corneal Densitometry as a Tool to Measure Epithelial Ingrowth After Laser In Situ Keratomileusis.

    Adran, Daniel; Vaillancourt, Louis; Harissi-Dagher, Mona; Kruh, Jonathan N; Syed, Zeba A; Robinson, Steven; Melki, Samir

    2017-04-01

    This study evaluates the correlation between corneal densitometry and epithelial ingrowth (EI) after laser in situ keratomileusis (LASIK). Corneal densitometry of 3 patients who developed EI after LASIK was measured with the Oculus Pentacam. Corneal densitometry readings of each patient were obtained preoperatively and postoperatively after ingrowth was discovered. Densitometry was recorded at the central nest of opacity and at the leading edges of EI. For all patients, the most severe stages of EI observed on slit-lamp photographs correlated with the highest densitometry readings, with peak densitometry ranging from 73.3 to 95.1. These values were much higher than preoperative densitometry readings, which ranged from 21.8 to 27.2. In 2 cases, the Pentacam densitometry map revealed progression of EI toward the visual axis that was only faintly detectable or not detectable at all on the corresponding slit-lamp photographs. Corneal densitometry seems to be an objective measure of the severity and progression of EI after LASIK.

  5. Current status of accelerated corneal cross-linking

    Michael Mrochen

    2013-01-01

    Full Text Available Corneal cross-linking with riboflavin is a technique to stabilize or reduce corneal ectasia, in diseases such as keratoconus and post-laser-assisted in situ keratomileusis (LASIK ectasia. There is an interest by patient as well as clinicians to reduce the overall treatment time. Especially, the introduction of corneal cross-linking in combination with corneal laser surgery demands a shorter treatment time to assure a sufficient patient flow. The principles and techniques of accelerated corneal cross-linking is discussed.

  6. Corneal hydrops induced by Bell’s paralysis in a case of corneal ectasia

    Lokman Aslan

    2017-09-01

    Full Text Available An 18-year-old male patient presented with suddenly decreased vision, itching, corneal edema and an inability to close the left eye. They had left Bell’s paralysis for two weeks and had used high diopter glasses for five years. The best corrected visual acuity was 0.4 in their right eye and counting fingers in the left eye. Biomicroscopic examination revealed thinning and steepening of the cornea in the right eye and anterior protrusion of the cornea, stromal edema and punctate disruption of the epithelium in the left eye. Topographic image of the right eye was consistent with keratoconus. Six months later, stromal edema gradually regressed and a corneal scar ensued. This case presentation emphasizes that Bell’s palsy may induce disease progression in a patient with preexisting corneal ectasia and results in corneal hydrops. [Arch Clin Exp Surg 2017; 6(3.000: 165-167

  7. Corneal-Wavefront guided transepithelial photorefractive keratectomy after corneal collagen cross linking in keratoconus

    Massimo Camellin

    2017-01-01

    Conclusions: Corneal-Wavefront guided transepithelial PRK ablation profiles after conventional CXL yields to good visual, optical, and refractive results. These treatments are safe and efficacious for the correction of refracto-therapeutic problems in keratoconic patients.

  8. Changes in corneal topography and biomechanical properties after collagen cross linking for keratoconus: 1-year results.

    Sedaghat, Mohammadreza; Bagheri, Mansooreh; Ghavami, Shahri; Bamdad, Shahram

    2015-01-01

    To evaluate changes in corneal topography and biomechanical properties after collagen cross-linking (CXL) for progressive keratoconus. Collagen cross-linking was performed on 97 eyes. We assessed uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA). Corneal topography indices were evaluated using placido disc topography, scanning slit anterior topography (Orbscan II), and rotating Scheimpflug topography (Pentacam). Specular microscopy and corneal biomechanics were evaluated. A 1-year-follow-up results revealed that UCVA improved from 0.31 to 0.45 and BCVA changed from 0.78 to 0.84 (P < 0.001). The mean of average keratometry value decreased from 49.62 to 47.95 D (P < 0.001). Astigmatism decreased from 4.84 to 4.24 D (P < 0.001). Apex corneal thickness decreased from 458.11 to 444.46 μm. Corneal volume decreased from 56.66 to 55.97 mm(3) (P < 0.001). Posterior best fit sphere increased from 55.50 to 46.03 mm (P = 0.025). Posterior elevation increased from 99.2 to 112.22 μm (P < 0.001). Average progressive index increased from 2.26 to 2.56 (P < 0.001). A nonsignificant decrease was observed in mean endothelial count from 2996 to 2928 cell/mm(2) (P = 0.190). Endothelial coefficient of variation (CV) increased nonsignificantly from 18.26 to 20.29 (P = 0.112). Corneal hysteresis changed from 8.18 to 8.36 (P = 0.552) and corneal resistance factor increased from 6.98 to 7.21 (P = 0.202), so these changes were not significant. Visual acuity and K values improved after CXL. In spite of the nonsignificant increase in endothelial cell count and increase in the CV, CLX seems to be a safe treatment for keratoconus. Further studies with larger sample sizes and longer follow-up periods are recommended.

  9. Characteristic of entire corneal topography and tomography for the detection of sub-clinical keratoconus with Zernike polynomials using Pentacam.

    Xu, Zhe; Li, Weibo; Jiang, Jun; Zhuang, Xiran; Chen, Wei; Peng, Mei; Wang, Jianhua; Lu, Fan; Shen, Meixiao; Wang, Yuanyuan

    2017-11-28

    The study aimed to characterize the entire corneal topography and tomography for the detection of sub-clinical keratoconus (KC) with a Zernike application method. Normal subjects (n = 147; 147 eyes), sub-clinical KC patients (n = 77; 77 eyes), and KC patients (n = 139; 139 eyes) were imaged with the Pentacam HR system. The entire corneal data of pachymetry and elevation of both the anterior and posterior surfaces were exported from the Pentacam HR software. Zernike polynomials fitting was used to quantify the 3D distribution of the corneal thickness and surface elevation. The root mean square (RMS) values for each order and the total high-order irregularity were calculated. Multimeric discriminant functions combined with individual indices were built using linear step discriminant analysis. Receiver operating characteristic curves determined the diagnostic accuracy (area under the curve, AUC). The 3rd-order RMS of the posterior surface (AUC: 0.928) obtained the highest discriminating capability in sub-clinical KC eyes. The multimeric function, which consisted of the Zernike fitting indices of corneal posterior elevation, showed the highest discriminant ability (AUC: 0.951). Indices generated from the elevation of posterior surface and thickness measurements over the entire cornea using the Zernike method based on the Pentacam HR system were able to identify very early KC.

  10. A role for topographic cues in the organization of collagenous matrix by corneal fibroblasts and stem cells.

    Dimitrios Karamichos

    Full Text Available Human corneal fibroblasts (HCF and corneal stromal stem cells (CSSC each secrete and organize a thick stroma-like extracellular matrix in response to different substrata, but neither cell type organizes matrix on tissue-culture polystyrene. This study compared cell differentiation and extracellular matrix secreted by these two cell types when they were cultured on identical substrata, polycarbonate Transwell filters. After 4 weeks in culture, both cell types upregulated expression of genes marking differentiated keratocytes (KERA, CHST6, AQP1, B3GNT7. Absolute expression levels of these genes and secretion of keratan sulfate proteoglycans were significantly greater in CSSC than HCF. Both cultures produced extensive extracellular matrix of aligned collagen fibrils types I and V, exhibiting cornea-like lamellar structure. Unlike HCF, CSSC produced little matrix in the presence of serum. Construct thickness and collagen organization was enhanced by TGF-ß3. Scanning electron microscopic examination of the polycarbonate membrane revealed shallow parallel grooves with spacing of 200-300 nm, similar to the topography of aligned nanofiber substratum which we previously showed to induce matrix organization by CSSC. These results demonstrate that both corneal fibroblasts and stromal stem cells respond to a specific pattern of topographical cues by secreting highly organized extracellular matrix typical of corneal stroma. The data also suggest that the potential for matrix secretion and organization may not be directly related to the expression of molecular markers used to identify differentiated keratocytes.

  11. Ultraviolet induced lysosome activity in corneal epithelium

    Cullen, A.P.

    1980-01-01

    A 5.000 W Xe-Hg high pressure lamp and a double monochromator were used to produce a 3.3 nm half-bandpass ultraviolet radiation at 295 nm. Pigmented rabbit eyes were irradiated with radiant exposures from 140 Jm/sup -2/ to 10.000 Jm/sup -2/ and evaluated by slit-lamp biomicroscopy, light and electron microscopy. Corneal threshold (Hsub(c) was 200 Jm/sup -2/ and lens threshold (Hsub(L)) was 7.500 Jm/sup -2/. The most repeatable and reliable corneal response to these levels of UV was the development of corneal epithelial granules. Histological changes included a loss of superficial epithelial cells and selective UV induced autolysis of the wing cells. It is suggested that the biomicroscopically observed granules are the clinical manifestation of the secondary lysosomes revealed by light and electron microscopy. It is proposed that UV breaks down the primary lysosome membranes to release hydrolytic enzymes which in turn form the secondary lysosomes during autolysis. Extreme levels of radiant exposure at 295 nm result in indiscriminate destruction of all layers of the corneal epithelium, but the posterior cornea was spared.

  12. Ultraviolet induced lysosome activity in corneal epithelium

    Cullen, A.P.

    1980-01-01

    A 5.000 W Xe-Hg high pressure lamp and a double monochromator were used to produce a 3.3 nm half-bandpass ultraviolet radiation at 295 nm. Pigmented rabbit eyes were irradiated with radiant exposures from 140 Jm -2 to 10.000 Jm -2 and evaluated by slit-lamp biomicroscopy, light and electron microscopy. Corneal threshold (Hsub(c) was 200 Jm -2 and lens threshold (Hsub(L)) was 7.500 Jm -2 . The most repeatable and reliable corneal response to these levels of UV was the development of corneal epithelial granules. Histological changes included a loss of superficial epithelial cells and selective UV induced autolysis of the wing cells. It is suggested that the biomicroscopically observed granules are the clinical manifestation of the secondary lysosomes revealed by light and electron microscopy. It is proposed that UV breaks down the primary lysosome membranes to release hydrolytic enzymes which in turn form the secondary lysosomes during autolysis. Extreme levels of radiant exposure at 295 nm result in indiscriminate destruction of all layers of the corneal epithelium, but the posterior cornea was spared. (orig.) [de

  13. Corneal ulcers: For the general practitioner

    Speci c enquiry as to instillation of medication (e.g. steroid drops) or home ... unaided and then with pinhole, with the fellow eye occluded. As a corneal ... topical anaesthetic drops will assist in making the patient comfortable enough to open ...

  14. Past and present of corneal refractive surgery

    Vestergaard, Anders Højslet

    Surgical correction of refractive errors is becoming increasingly popular. In the 1990s, the excimer laser revolutionized the field of corneal refractive surgery with PRK and LASIK, and lately refractive lenticule extraction (ReLEx) of intracorneal tissue, using only a femtosecond laser, has become...

  15. Management of Corneal Bee Sting Injuries.

    Rai, Ruju R; Gonzalez-Gonzalez, Luis A; Papakostas, Thanos D; Siracuse-Lee, Donna; Dunphy, Robert; Fanciullo, Lisa; Cakiner-Egilmez, Tulay; Daly, Mary K

    2017-01-01

    To review the management of keratitis after corneal bee stings and to report a case of deep stromal corneal infiltrate secondary to a retained bee stinger managed conservatively in a patient who presented three days after unsanitary manipulation of the stinger apparatus. Case report and review of literature. A 57-year-old male beekeeper was evaluated for pain, blurry vision, and photosensitivity after a corneal bee sting. Of note, the venom sac had been removed with dirty tweezers three days prior to his visit. On exam, a focal infiltrate with diffuse edema was seen surrounding a retained bee stinger in the peripheral cornea. Trace cells in the anterior chamber were also noted. Based on a high suspicion for infectious keratitis, a conservative treatment strategy was elected. Administration of broad-spectrum topical antibiotics with concomitant abstention of corticosteroids led to rapid resolution of the symptoms. Over 16 months of follow-up, the stinger has remained in situ without migration and the patient has maintained 20/20 visual acuity without complications. There is debate on the preferred method for the management of corneal injury secondary to bee stings, especially when it is associated with a retained stinger. We herein present our findings in our appraisal of reported cases. In the aftermath of an ocular bee sting, close surveillance for inflammation and infection is essential. Individual manifestations of these injuries vary in timing, type, and severity; therefore, the accessibility of the stinger and the evolving clinical picture should guide therapeutic decisions.

  16. 21 CFR 886.1220 - Corneal electrode.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Corneal electrode. 886.1220 Section 886.1220 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... to the cornea to provide data showing the changes in electrical potential in the retina after...

  17. Corneal topography measurements for biometric applications

    Lewis, Nathan D.

    The term biometrics is used to describe the process of analyzing biological and behavioral traits that are unique to an individual in order to confirm or determine his or her identity. Many biometric modalities are currently being researched and implemented including, fingerprints, hand and facial geometry, iris recognition, vein structure recognition, gait, voice recognition, etc... This project explores the possibility of using corneal topography measurements as a trait for biometric identification. Two new corneal topographers were developed for this study. The first was designed to function as an operator-free device that will allow a user to approach the device and have his or her corneal topography measured. Human subject topography data were collected with this device and compared to measurements made with the commercially available Keratron Piccolo topographer (Optikon, Rome, Italy). A third topographer that departs from the standard Placido disk technology allows for arbitrary pattern illumination through the use of LCD monitors. This topographer was built and tested to be used in future research studies. Topography data was collected from 59 subjects and modeled using Zernike polynomials, which provide for a simple method of compressing topography data and comparing one topographical measurement with a database for biometric identification. The data were analyzed to determine the biometric error rates associated with corneal topography measurements. Reasonably accurate results, between three to eight percent simultaneous false match and false non-match rates, were achieved.

  18. Simultaneous topography-guided PRK followed by corneal collagen cross-linking after lamellar keratoplasty for keratoconus

    Spadea L

    2012-11-01

    Full Text Available Leopoldo Spadea,1 Marino Paroli21University of L’Aquila, Department of Biotechnological and Applied Clinical Sciences, Eye Clinic, L’Aquila, 2La Sapienza University, Department of Biotechnology and Medical-Surgical Sciences, Latina, ItalyBackground: The purpose of this paper is to report the results of using combined treatment of customized excimer laser-assisted photorefractive keratectomy (PRK and prophylactic corneal collagen crosslinking (CXL for residual refractive error in a group of patients who had previously undergone lamellar keratoplasty for keratoconus.Methods: The study included 14 eyes from 14 patients who had originally been treated for keratoconus in one eye by excimer laser-assisted lamellar keratoplasty (ELLK, and subsequently presented with residual ametropia (-6.11 D ± 2.48, range -2.50 to -9.50. After a mean 40.1 ± 12.4 months since ELLK they underwent combined simultaneous corneal regularization treatment with topographically guided transepithelial excimer laser PRK (central corneal regularization and corneal CXL induced by riboflavin-ultraviolet A.Results: After a mean 15 ± 6.5 (range 6–24 months, all eyes gained at least one Snellen line of uncorrected distance visual acuity (range 1–10. No patient lost lines of corrected distance visual acuity, and four patients gained three lines of corrected distance visual acuity. Mean manifest refractive spherical equivalent was -0.79 ± 2.09 (range +1 to -3.0 D, and topographic keratometric astigmatism was 5.02 ± 2.93 (range 0.8–8.9 D. All the corneas remained clear (haze < 1.Conclusion: The combination of customized PRK and corneal CXL provided safe and effective results in the management of corneal regularization for refractive purposes after ELLK for keratoconus.Keywords: corneal collagen crosslinking, excimer laser-assisted lamellar keratoplasty, photorefractive keratectomy

  19. Femtosecond laser cutting of multiple thin corneal stromal lamellae for endothelial bioengineering.

    Bernard, Aurélien; He, Zhiguo; Forest, Fabien; Gauthier, Anne-Sophie; Peocʼh, Michel; Dumollard, Jean-Marc; Acquart, Sophie; Montard, Romain; Delbosc, Bernard; Gain, Philippe; Thuret, Gilles

    2015-02-01

    To assess the feasibility of cutting multiple thin stromal lamellae in human donor corneas using a commercial femtosecond laser (FSL) to provide cell carriers for future endothelial graft bioengineering. Eight edematous organ-cultured corneas not suitable for grafting for endothelial reasons were mounted on a Ziemer anterior chamber and cut with a Z6 FSL with 6 successive parallel cuts, from depth to surface. Target thickness of each lamella ranged from 100 to 150 μm depending on initial corneal thickness. Thickness was measured using anterior segment optical coherence tomography before and after cutting on mounted corneas, and on each stromal lamella after detachment. Scanning electron microscopy observation was performed on 4 lamellae and histological cross sections on 1 cornea before detachment. A median of 5 (minimum 3, maximum 7) lamellae was obtained per cornea. All lamellae still attached were the most posterior ones, suggesting that FSL was less efficient because of light scattering by edematous stroma. Cut precision and postdetachment swelling were correlated with anterior-posterior position within the cornea. Median lamella thickness was 127 μm (56-222 μm) before detachment and 196 μm (80-304 μm) after detachment. Surface state was consistent with previously reported FSL lamellar cuts during Descemet stripping automated endothelial keratoplasty. Up to 7 thin lamellae can be cut in stored corneas with an FSL. This method, once optimized primarily by using deswelled, more transparent corneas, could prove effective for recycling unsuitable donor corneas in corneal bioengineering processes.

  20. Effect of chemical composition on corneal tissue response to photopolymerized materials comprising 2-hydroxyethyl methacrylate and acrylic acid

    Lai, Jui-Yang, E-mail: jylai@mail.cgu.edu.tw

    2014-01-01

    The purpose of this work was to investigate the relationship between the feed composition of 2-hydroxyethyl methacrylate (HEMA)/acrylic acid (AAc) and hydrogel material compatibility towards ocular anterior segment tissues, particularly the corneal endothelium. The monomer solutions of HEMA and AAc were mixed at varying volume ratios of 92:0, 87:5, 82:10, 77:15, and 72:20, and were subjected to UV irradiation. Then, the 7-mm-diameter membrane implants made from photopolymerized materials were placed into the ocular anterior chamber for 4 days and assessed by biomicroscopic examinations, corneal thickness measurements, and quantitative real-time reverse transcription polymerase chain reaction analyses. The poly(HEMA-co-AAc) implants prepared from the solution mixture containing 0–10 vol.% AAc displayed good biocompatibility. However, with increasing volume ratio of AAc and HEMA from 15:77 to 20:72, the enhanced inflammatory response, decreased endothelial cell density, and increased ocular score and corneal thickness were observed, probably due to the influence of surface charge of copolymer membranes. On the other hand, the ionic pump function of corneal endothelium exposed to photopolymerized membranes was examined by analyzing the Na{sup +},K{sup +}-ATPase alpha 1 subunit (ATP1A1) expression level. The presence of the implants having higher amount of AAc incorporated in the copolymers (i.e., 15.1 to 24.7 μmol) and zeta potential (i.e., -38.6 to − 56.5 mV) may lead to abnormal transmembrane transport. It is concluded that the chemical composition of HEMA/AAc has an important influence on the corneal tissue responses to polymeric biomaterials. - Highlights: • We examine the corneal tissue responses to photopolymerized biomaterials. • Carboxyl groups in copolymers increased with increasing volume ratio of AAc/HEMA. • 15–20 vol.% AAc raised ocular score and caused corneal endothelial loss and edema. • High anionic charge density stimulated inflammation

  1. The steroids for corneal ulcers trial: study design and baseline characteristics.

    Srinivasan, Muthiah; Mascarenhas, Jeena; Rajaraman, Revathi; Ravindran, Meenakshi; Lalitha, Prajna; Glidden, David V; Ray, Kathryn J; Hong, Kevin C; Oldenburg, Catherine E; Lee, Salena M; Zegans, Michael E; McLeod, Stephen D; Lietman, Thomas M; Acharya, Nisha R

    2012-02-01

    To provide comprehensive trial methods and baseline data for the Steroids for Corneal Ulcers Trial and to present epidemiological characteristics such as risk factors, causative organisms, and ulcer severity. Baseline data from a 1:1 randomized, placebo-controlled, double-masked clinical trial comparing prednisolone phosphate, 1%, with placebo as adjunctive therapy for the treatment of bacterial corneal ulcers. Eligible patients had a culture-positive bacterial corneal ulcer and had been taking moxifloxacin for 48 hours. The primary outcome for the trial is best spectacle-corrected visual acuity at 3 months from enrollment. This report provides comprehensive baseline data, including best spectacle-corrected visual acuity, infiltrate size, microbiological results, and patient demographics, for patients enrolled in the trial. Of 500 patients enrolled, 97% were in India. Two hundred twenty patients (44%) were agricultural workers. Median baseline visual acuity was 0.84 logMAR (Snellen, 20/125) (interquartile range, 0.36-1.7; Snellen, 20/50 to counting fingers). Baseline visual acuity was not significantly different between the United States and India. Ulcers in India had larger infiltrate/scar sizes (P = .04) and deeper infiltrates (P = .04) and were more likely to be localized centrally (P = .002) than ulcers enrolled in the United States. Gram-positive bacteria were the most common organisms isolated from the ulcers (n = 366, 72%). The Steroids for Corneal Ulcers Trial will compare the use of a topical corticosteroid with placebo as adjunctive therapy for bacterial corneal ulcers. Patients enrolled in this trial had diverse ulcer severity and on average significantly reduced visual acuity at presentation. clinicaltrials.gov Identifier: NCT00324168.

  2. SOME TECHNIQUES IN CORNEAL GRAFTING

    1971-04-10

    Apr 10, 1971 ... current herpes corneae. The visual acuity was less than. 6/60. The left eye had had a central nebula since child- hood and was deemed amblyopic. Six weeks after a 7 x 0·3 mm lamellar graft in the right eye was placed, ulceration occurred in the graft junction. A total thin conjunctival flap was sutured over.

  3. Avaliação da qualidade de corte do microceratótomo Masyk® na confecção de lamela corneana pediculada em olhos porcinos Evaluation of the cut quality of the Masyk® microkeratome in obtaining corneal flap from porcine eyes

    Gustavo Victor

    2006-02-01

    Full Text Available OBJETIVO: Avaliar a qualidade de corte do microceratótomo Masyk® na confecção de lamela corneana pediculada em olhos porcinos. MÉTODOS: Realizou-se estudo prospectivo na Eye Clinic Day Hospital (São Paulo, Brasil em 31 olhos porcinos divididos em 2 grupos: 15 olhos nos quais se utilizou a plataforma de 160 µm e anel de sucção de 9,5 mm de diâmetro (Grupo 1 e 16 olhos, submetidos à plataforma de 140 µm e anel de sucção de 8,5 mm de diâmetro (Grupo 2. As espessuras efetivas das lamelas foram aferidas pelo paquímetro P55 (Paradigm, EUA e os diâmetros verticais do leito estromal com compasso cirúrgico. RESULTADOS: Não ocorreram complicações durante a utilização do microceratótomo e não foram identificadas lamelas livres, perfuradas ou incompletas. No grupo 1, a média das espessuras efetiva foi de 146,33 ± 15,43 µm, com variação entre 127 e 186 µm. A média das medidas do diâmetro vertical do leito residual foi de 9,39 ± 0,26 mm, com variação entre 8,90 e 9,85 mm. No grupo 2, a média das espessuras efetiva foi de 128,75 ± 18,83 µm, com variação entre 71 e 178 µm. A média das medidas do diâmetro do leito residual foi de 8,27 ± 0,20 mm, com variação entre 7,95 e 8,65 mm. CONCLUSÃO: O microceratótomo Masyk® mostrou-se eficaz e seguro em confeccionar lamelas corneanas pediculadas de espessura e diâmetros adequados em olhos porcinos.PURPOSE: Evaluation of the cut quality of the Masyk® microkeratome in obtaining corneal flap from porcine eyes. METHODS: Prospective study with 31 porcine eyes divided into two groups: 15 eyes with programmed flap thickness of 160 µm and 9.5 mm diameter (Group 1, and 16 eyes with programmed flap thickness of 140 µm and 8.5 mm diameter (Group 2. Corneal thickness was calculated with a P55 pachymeter (Paradigm, USA and the diameter with compass. RESULTS: No complications were observed during the use of the microkeratome. In group 1, the central corneal thickness mean was 146

  4. Unilateral corneal leukoplakia without limbal involvement

    Hirano K

    2015-05-01

    Full Text Available Koji Hirano,1 Mihoko Koide,2 Yoshikazu Mizoguchi,3 Yasuhiro Osakabe,4 Kaoru-Araki Sasaki5 1Department of Ophthalmology, Ban Buntane Hotokukai Hospital, School of Medicine, Fujita Health University, Nagoya, Japan; 2Koide Internal Medicine and Eye Clinic, Nagoya, Japan; 3Department of Pathology, Ban Buntane Hotokukai Hospital, School of Medicine, Fujita Health University, Nagoya, Japan; 4Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan; 5Department of Ophthalmology, Japan Health Care Organization, Hoshigaoka Medical Center, Hirakata, Japan Purpose: Leukoplakia is the term given to a white patch or plaque that is found mainly on the oral mucus membrane. It can occasionally be seen on the corneal surface. We report our clinical and histopathological findings in a case of unilateral corneal leukoplakia. Methods: A 26-year-old woman was referred to our hospital because of a white patch on her right cornea that continued to expand. She first noticed the white patch when she was 20 years old, and the white patch had expanded to cover the pupillary area affecting her vision. After plastic surgery on both eyelids for bilateral entropion to alleviate the pain caused by the eyelashes rubbing the cornea, the white corneal patch decreased in size. Because of this reduction, we performed surgery to remove the patch with microforceps under topical anesthesia. The plaque was removed easily and completely, and submitted for histopathological examination. Results: Histopathological examination showed that the specimen had characteristics of epidermis with a basal cell layer, spinous cell layer, granular cell layer, and horny layer with hyperkeratosis. She was diagnosed with leukoplakia of the corneal surface. The basic structure of the squamous cell layer was preserved, and there were no signs of metaplasia. Six months after the removal of the leukoplakia, no recurrence was seen and her corrected decimal visual acuity recovered to 1

  5. Corneal Graft Rejection: Incidence and Risk Factors

    Alireza Baradaran-Rafii

    2008-12-01

    Full Text Available

    PURPOSE: To determine the incidence and risk factors of late corneal graft rejection after penetrating keratoplasty (PKP. METHODS: Records of all patients who had undergone PKP from 2002 to 2004 without immunosuppressive therapy other than systemic steroids and with at least one year of follow up were reviewed. The role of possible risk factors such as demographic factors, other host factors, donor factors, indications for PKP as well as type of rejection were evaluated. RESULTS: During the study period, 295 PKPs were performed on 286 patients (176 male, 110 female. Mean age at the time of keratoplasty was 38±20 (range, 40 days to 90 years and mean follow up period was 20±10 (range 12-43 months. Graft rejection occurred in 94 eyes (31.8% at an average of 7.3±6 months (range, 20 days to 39 months after PKP. The most common type of rejection was endothelial (20.7%. Corneal vascularization, regrafting, anterior synechiae, irritating sutures, active inflammation, additional anterior segment procedures, history of trauma, uncontrolled glaucoma, prior graft rejection, recurrence of herpetic infection and eccentric grafting increased the rate of rejection. Patient age, donor size and bilateral transplantation had no significant influence on graft rejection. CONCLUSION: Significant risk factors for corneal graft rejection include

  6. Induction of corneal collagen cross-linking in experimental corneal alkali burns in rabbits

    Marcello Colombo-Barboza

    2014-10-01

    Full Text Available Objective: To evaluate the effect of riboflavin-ultraviolet-A-induced cross-linking (CXL following corneal alkali burns in rabbits. Methods: The right corneas and limbi of ten rabbits were burned using a 1N solution of NaOH and the animals were then divided into two groups: a control group submitted to clinical treatment alone and an experimental group that was treated 1 h after injury with CXL, followed by the same clinical treatment as administered to the controls. Clinical parameters were evaluated post-injury at 1, 7, 15, and 30 days by two independent observers. Following this evaluation, the corneas were excised and examined histologically. Results: There were no statistically significant differences in clinical parameters, such as hyperemia, corneal edema, ciliary injection, limbal ischemia, secretion, corneal neovascularization, symblepharon, or blepharospasm, at any of the time-points evaluated. However, the size of the epithelial defect was significantly smaller in the CXL group (p<0.05 (day 15: p=0.008 and day 30: p=0.008 and the extent of the corneal injury (opacity lesion was also smaller (day 30: p=0.021. Histopathology showed the presence of collagen bridges linking the collagen fibers in only the CXL group. Conclusions: These results suggest that the use of CXL may improve the prognosis of acute corneal alkali burns.

  7. [The correlations between corneal sensation, tear meniscus volume, and tear film osmolarity after femtosecond laser-assisted LASIK].

    Zhang, Luyan; Sun, Xiyu; Yu, Ye; Xiong, Yan; Cui, Yuxin; Wang, Qinmei; Hu, Liang

    2016-01-01

    To investigate the correlations between corneal sensation, tear meniscus volume, and tear film osmolarity after femtosecond laser-assisted LASIK (FS-LASIK) surgery. In this prospective clinical study, 31 patients undergoing FS-LASIK for myopia were recruited. The upper and lower tear meniscus volumes (UTMV and LTMV) were measured by customized anterior segment optical coherence tomography, tear film osmolarity was measured by a TearLab Osmolarity test device, central corneal sensation was measured by a Cochet-Bonner esthesiometer preoperatively, at 1 week, 1 and 3 months postoperatively. Repeated measures analysis of variance was used to evaluate whether the tear film osmolarity, tear meniscus volume, and corneal sensation were changed after surgery. The correlations between these variables were analyzed by the Pearson correlation analysis. The tear film osmolarity was (310.03 ± 16.48) mOsms/L preoperatively, (323.51 ± 15.92) mOsms/L at 1 week, (319.93 ± 14.27) mOsms/L at 1 month, and (314.97±12.91) mOsms/L at 3 months. The UTMV was (0.42±0.15), (0.25± 0.09), (0.30±0.11), and (0.35±0.09) μL, respectively; the LTMV was (0.60±0.21),(0.37±0.08), (0.44± 0.14), and (0.52±0.17) μL, respectively. The tear film osmolarity was significantly higher at 1 week and 1 month postoperatively compared with the baseline (P=0.001, 0.004), and reduced to the preoperative level at 3 months (P=0.573). The UTMV, LTMV, and corneal sensation values presented significant decreases at all postoperative time points (all Psensation at 1 week after surgery (r=0.356,P=0.005). There were significant correlations between the preoperative LTMV and corneal sensation at 1 week, 1 and 3 months (respectively, r=0.422, 0.366, 0.352;P=0.001, 0.004, 0.006). No significant correlations were found between the tear film osmolarity, tear meniscus volume, and corneal sensation after surgery (all P>0.05). The tear film osmolarity, tear meniscus volume, and corneal sensation became aggravated due

  8. [The status quo and expectation of corneal research in China].

    Shi, Weiyun; Xie, Lixin

    2014-09-01

    In China, corneal disease is currently the second leading cause of blindness. Severe donor shortage, insufficient technique supports and promotion, and the lack of corneal disease specialists due to poor systematic training are all urgent problems to be resolved. The last 5 years have witnessed a considerable progress in basic and clinical researches of corneal disease. Investigations on the pathogenesis and treatment of fungal keratitis have won an international reputation. Results from the study of corneal reconstruction with tissue-engineered and acellular matrix corneas have been tested in clinical trials with good preliminary performance. Moreover, the clinical researches of corneal refractive surgery have kept pace with the latest international progresses. However, Descemet's membrane endothelial keratoplasty needs further promotion, and the development and application of keratoprosthesis remains a blank. Although keratoprosthesis and corneal collagen cross-linking have been widely applied in Europe with satisfactory clinical efficacy, they are still under assessment by China Food and Drug Administration for approval of use.

  9. Application of Novel Drugs for Corneal Cell Regeneration

    Sang Beom Han

    2018-01-01

    Full Text Available Corneal transplantation has been the only treatment method for corneal blindness, which is the major cause of reversible blindness. However, despite the advancement of surgical techniques for corneal transplantation, demand for the surgery can never be met due to a global shortage of donor cornea. The development of bioengineering and pharmaceutical technology provided us with novel drugs and biomaterials that can be used for innovative treatment methods for corneal diseases. In this review, the authors will discuss the efficacy and safety of pharmacologic therapies, such as Rho-kinase (ROCK inhibitors, blood-derived products, growth factors, and regenerating agent on corneal cell regeneration. The promising results of these agents suggest that these can be viable options for corneal reconstruction and visual rehabilitation.

  10. Effect of Cycloplegia on Corneal Biometrics and Refractive State.

    Bagheri, Abbas; Feizi, Mohadeseh; Shafii, Aliakbar; Faramarzi, Amir; Tavakoli, Mehdi; Yazdani, Shahin

    2018-01-01

    To determine changes in refractive state and corneal parameters after cycloplegia with cyclopentolate hydrochloride 1% using a dual Scheimpflug imaging system. In this prospective cross-sectional study patients aged 10 to 40 years who were referred for optometric evaluation enrolled and underwent autorefraction and corneal imaging with the Galilei dual Scheimpflug system before and 30 minutes after twice instillation of medication. Changes in refraction and astigmatism were investigated. Corneal biometrics including anterior and posterior corneal curvatures, total corneal power and corneal pachymetry were compared before and after cycloplegia. Two hundred and twelve eyes of 106 subjects with mean age of 28 ± 5 years including 201 myopic and 11 hyperopic eyes were evaluated. Mean spherical equivalent refractive error before cycloplegia was -3.4 ± 2.6 D. A mean hyperopic shift of 0.4 ± 0.5 D occurred after cycloplegia ( P biometrics should be considered before cataract and refractive surgeries.

  11. Corneal Collagen Cross-Linking with Hypoosmolar Riboflavin Solution in Keratoconic Corneas

    Shaofeng Gu

    2014-01-01

    Full Text Available Purpose. To report the 12-month outcomes of corneal collagen cross-linking (CXL with a hypoosmolar riboflavin and ultraviolet-A (UVA irradiation in thin corneas. Methods. Eight eyes underwent CXL using a hypoosmolar riboflavin solution after epithelial removal. The corrected distance visual acuity (CDVA, manifest refraction, the mean thinnest corneal thickness (MTCT, and the endothelial cell density (ECD were evaluated before and 6 and 12 months after CXL. Results. The MTCT was 413.9 ± 12.4 μm before treatment and reduced to 381.1 ± 7.3 μm after the removal of the epithelium. After CXL, the thickness decreased to 410.3 ± 14.5 μm at the last follow-up. Before treatment, the mean K-value of the apex of the keratoconus corneas was 58.7 ± 3.5 diopters and slightly decreased (57.7 ± 4.9 diopters at 12 months. The mean CDVA was 0.54 ± 0.23 logarithm of the minimal angle of resolution before treatment and increased to 0.51 ± 0.21 logarithm at the last follow-up. The ECD was 2731.4 ± 191.8 cells/mm2 before treatment and was 2733.4 ± 222.6 cells/mm2 at 12 months after treatment. Conclusions. CXL with a hypoosmolar riboflavin in thin corneas seems to be a promising method for keratoconic eyes with the mean thinnest corneal thickness less than 400 μm without epithelium.

  12. Corneal Biofilms: From Planktonic to Microcolony Formation in an Experimental Keratitis Infection with Pseudomonas Aeruginosa.

    Saraswathi, Padmanabhan; Beuerman, Roger W

    2015-10-01

    Microbial biofilms commonly comprise part of the infectious scenario, complicating the therapeutic approach. The purpose of this study was to determine in a mouse model of corneal infection if mature biofilms formed and to visualize the stages of biofilm formation. A bacterial keratitis model was established using Pseudomonas aeruginosa ATCC 9027 (1 × 10(8) CFU/ml) to infect the cornea of C57BL/6 black mouse. Eyes were examined post-infection (PI) on days 1, 2, 3, 5, and 7, and imaged by slit lamp microscopy, and light, confocal, and electron microscopy to identify the stages of biofilm formation and the time of appearance. On PI day 1, Gram staining showed rod-shaped bacteria adherent on the corneal surface. On PI days 2 and 3, bacteria were seen within webs of extracellular polymeric substance (EPS) and glycocalyx secretion, imaged by confocal microscopy. Scanning electron microscopy demonstrated microcolonies of active infectious cells bound with thick fibrous material. Transmission electron microscopy substantiated the formation of classical biofilm architecture with P. aeruginosa densely packed within the extracellular polymeric substances on PI days 5 and 7. Direct visual evidence showed that biofilms routinely developed on the biotic surface of the mouse cornea. The mouse model can be used to develop new approaches to deal therapeutically with biofilms in corneal infections. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  13. Limitations in imaging common conjunctival and corneal pathologies with fourier-domain optical coherence tomography.

    Demirci, Hakan; Steen, Daniel W

    2014-01-01

    To describe the limitations of Fourier-domain optical coherence tomography (OCT) in imaging common conjunctival and corneal pathology. Retrospective, single-center case series of 40 patients with conjunctival and cornea pathology. Fourier-domain OCT imaged laser in situ keratomileusis (LASIK) flaps in detail, including its relation to other corneal structures and abnormalities. Similarly, in infectious or degenerative corneal disorders, Fourier-domain OCT successfully showed the extent of infiltration or material deposition, which appeared as hyper-reflective areas. In cases with pterygium, the underlying cornea could not be imaged. All cases of common conjunctival pathologies, such as nevus or pinguecula, were successfully imaged in detail. Nevi, scleritis, pterygium, pinguecula, and subconjunctival hemorrhage were hyper-reflective lesions, while cysts and lymphangiectasia were hyporeflective. The details of the underlying sclera were not uniformly imaged in conjunctival pathologies. Fourier-domain OCT imaged the trabeculectomy bleb in detail, whereas the details of structures of the anterior chamber angle were not routinely visualized in all cases. Light scatter through vascularized, densely inflamed, or thick lesions limits the imaging capabilities of Fourier-domain anterior segment OCT.

  14. [Clinical observation on corneal transparency after small incision lenticule extraction surgery].

    Zhang, L; Wang, Y; Cui, T; Zhao, W; Cheng, W B

    2018-01-11

    overall postoperative CD increased in the first week after surgery (1 day to 15.90, 1 week to 15.65), and then decreased to the equivalent of baseline levels and maintained such level until 6 months after surgery (1 month to 15.60; 3 month to 15.50, 6 month to 15.55), though at the 12-month follow-up, densitometry values had spiked significantly again (12 month, 15.90). The difference between the preoperative and postoperative CD values in the central two zones (≤2 mm, >2 mm and ≤6 mm), but not the outer (>6 mm and ≤10 mm), were of statistical significance (χ(2)=61.961, 52.397, Ptransparency decreased) as compared to the preoperative baseline on the first postoperative day, and lasted through the first week. There were no significant changes in the CD of the central layer (χ(2)=0.918, P =0.986). Significant increases in the posterior 60 μm of the cornea after surgery were found only at the 6-month and 1-year follow-up examinations (χ(2)=17.469, P= 0.008). No correlation was found in the preoperative refractive error, ablation depth, postoperative UCVA and the CD. The CD at 6 months was found negatively correlated with SE at 6 months ( r= -0.219, P =0.028). Conclusions: SMILE reduced corneal transparency temporarily and primarily within the surgically altered area, however such change has no significant correlation with the ablation depth, SE, and the postoperative UCVA. Transparency recovered within a month, but patients should be monitored for at least 1 year. (Chin J Ophthalmol, 2018, 54: 27-32) .

  15. Posterior amorphous corneal dystrophy: case report

    Oliveira, Lauro Augusto de [UNIFESP; Vieira, Luiz Antônio [UNIFESP; Freitas, Denise de [UNIFESP; Sousa, Luciene Barbosa de [UNIFESP

    2006-01-01

    O objetivo deste trabalho é alertar o oftalmologista da possibilidade de se deparar com casos raros de distrofias corneanas. Neste caso correlacionamos os achados clínicos da distrofia amorfa posterior com refração, topografia e biomicroscopia ultra-sônica.The purpose of this paper is to warn the ophthalmologist about the possibility of facing rare cases of corneal dystrophies. Clinical findings of a case of posterior amorphous dystrophy were correlated with refraction, topography, and ultras...

  16. RECURRENT CORNEAL EROSION SYNDROME (a review

    S. V. Trufanov

    2015-01-01

    Full Text Available Recurrent corneal erosion (RCE syndrome is characterized by episodes of recurrent spontaneous epithelial defects. Main clinical symptoms (pain, redness, photophobia, lacrimation occurred at night. Corneal lesions revealed by slit lamp exam vary depending on the presence of corneal epithelium raise, epithelial microcysts or epithelial erosions, stromal infiltrates and opacities. Microtraumas, anterior corneal dystrophies, and herpesvirus give rise to RCE. Other causes or factors which increase the risk of RCE syndrome include meibomian gland dysfunction, keratoconjunctivitis sicca, diabetes, and post-LASIK conditions. Basal membrane abnormalities and instability of epithelial adhesion to stroma play a key role in RCE pathogenesis. Ultrastructural changes in RCE include abnormalities of basal epithelial cells and epithelial basal membrane, absence or deficiency of semi-desmosomes, loss of anchor fibrils. Increase in matrix metalloproteinases and collagenases which contribute to basal membrane destruction results in recurrent erosions and further development of abnormal basal membrane. The goals of RCE therapy are to reduce pain (in acute stage, to stimulate re-epithelization, and to restore «adhesion complex» of basal membrane. In most cases, RCE responds to simple conservative treatment that includes lubricants, healing agents, and eye patches. RCEs that are resistant to simple treatment, require complex approach. Non-invasive methods include long-term contact lens use, instillations of autologous serum (eye drops, injections of botulinum toxin (induces ptosis, antiviral agent use or oral intake of metalloproteinase inhibitors. Cell membrane stabilizers, i.e., antioxidants, should be included into treatment approaches as well. Antioxidant effect of Emoxipine promotes tissue reparation due to the prevention of cell membrane lipid peroxidation as well as due to its anti-hypoxic, angioprotective, and antiplatelet effects. If conservative therapy

  17. Hipertensão ocular "mascarada" por edema de córnea após cirurgia da catarata Ocular hipertension confounded by corneal edema after cataract surgery

    Bruno de Freitas Valbon

    2009-12-01

    intraocular pressure (IOP measurements in cases with thick and flatter corneas. This is thought to occur linearly based on mathematical and on experimental studies. However, such influence does exist, but this is more complex than the one anticipated by pachymetry and keratometry because it is related to corneal biomechanical properties. The ocular response analyzer (ORA Reichert provides the data related to the biomechanical properties of the cornea along with the IOP measurements that are calibrated for correlating to the Goldmann applanation and also compensated from corneal properties. Also corneal tomography with a pachymetric map evaluation characterizes the cornea beyond central thickness and anterior curvature. In this article, we report a case of a 77 years old female patient with low vision, photofobia and ocular pain 28 days after phacoemulsification and intraocular lens implant. In the first visit, GAT was 14mmHg, while IOPcc (ORA corneal compensated IOP was 25,6mmHg. Corneal hysteresis and resistance factor were low: 4,1 and 6,1mmHg respectively despite a central thickness of 601 micron. Corneal thickness spatial profile was attenuated with an edematous pattern that was also observed by the Scheimpflug images (Pentacam. Hypertensive uveitis was diagnosed and the patient was started on a fixed combination of timolol and brimonidine associate with prednisolone acetate. Three weeks after, the patient referred resolution of photofobia and marked improvement of vision. Clinically, edema was resolved as observed by corneal tomographyc and biomechanical findings.

  18. Corneal neurotoxicity due to topical benzalkonium chloride.

    Sarkar, Joy; Chaudhary, Shweta; Namavari, Abed; Ozturk, Okan; Chang, Jin-Hong; Yco, Lisette; Sonawane, Snehal; Khanolkar, Vishakha; Hallak, Joelle; Jain, Sandeep

    2012-04-06

    The aim of this study was to determine and characterize the effect of topical application of benzalkonium chloride (BAK) on corneal nerves in vivo and in vitro. Thy1-YFP+ neurofluorescent mouse eyes were treated topically with vehicle or BAK (0.01% or 0.1%). Wide-field stereofluorescence microscopy was performed to sequentially image the treated corneas in vivo every week for 4 weeks, and changes in stromal nerve fiber density (NFD) and aqueous tear production were determined. Whole-mount immunofluorescence staining of corneas was performed with antibodies to axonopathy marker SMI-32. Western immunoblot analyses were performed on trigeminal ganglion and corneal lysates to determine abundance of proteins associated with neurotoxicity and regeneration. Compartmental culture of trigeminal ganglion neurons was performed in Campenot devices to determine whether BAK affects neurite outgrowth. BAK-treated corneas exhibited significantly reduced NFD and aqueous tear production, and increased inflammatory cell infiltration and fluorescein staining at 1 week (P reduction in neurites occurred after BAK addition to compartmental cultures of dissociated trigeminal ganglion cells. Although both BAK doses (0.0001% and 0.001%) reduced nerve fiber length, the reduction was significantly more with the higher dose (P < 0.001). Topical application of BAK to the eye causes corneal neurotoxicity, inflammation, and reduced aqueous tear production.

  19. Modification of the laser triangulation method for measuring the thickness of optical layers

    Khramov, V. N.; Adamov, A. A.

    2018-04-01

    The problem of determining the thickness of thin films by the method of laser triangulation is considered. An expression is derived for the film thickness and the distance between the focused beams on the photo detector. The possibility of applying the chosen method for measuring thickness is in the range [0.1; 1] mm. We could resolve 2 individual light marks for a minimum film thickness of 0.23 mm. We resolved with the help of computer processing of photos with a resolution of 0.10 mm. The obtained results can be used in ophthalmology for express diagnostics during surgical operations on the corneal layer.

  20. Regeneration of defective epithelial basement membrane and restoration of corneal transparency

    Marino, Gustavo K.; Santhiago, Marcony R.; Santhanam, Abirami; Torricelli, Andre A. M.; Wilson, Steven E.

    2018-01-01

    PURPOSE To study regeneration of the normal ultrastructure of the epithelial basement membrane (EBM) in rabbit corneas that had -9D photorefractive keratectomy (PRK) and developed late haze (fibrosis) with restoration of transparency over one to four months after surgery and in corneas that had incisional wounds. METHODS Twenty-four rabbits had one of their eyes included into one of the two procedure groups (-9D PRK or nearly full-thickness incisional wounds), while the opposite eye serving as unwounded controls. All corneas were evaluated with slit lamp photos, transmission electron microscopy and immunohistochemistry for the myofibroblast marker alpha-smooth muscle actin and collagen type III. RESULTS In the ‘-9D PRK group’, corneas at one month after surgery had dense corneal haze and no evidence of regenerated EBM ultrastructure. By two months after surgery, however, small areas of stromal clearing began to appear within the confluent opacity (lacunae), and these corresponded to small islands of normally-regenerated EBM detected within larger area of the excimer laser-ablated zone with no evidence of normal EBM. By four months after surgery, the EBM was fully-regenerated and the corneal transparency was completely restored to the ablated zone. In the ‘Incisional wound group’, the two dense, linear corneal opacities were observed at one month after surgery and progressively faded by two and three months after surgery. The EBM ultrastructure was fully regenerated at the site of the incisions, including around epithelial plugs that extended into the stroma, by one month after surgery in all eyes. CONCLUSIONS In the rabbit model, spontaneous resolution of corneal fibrosis (haze) after high correction PRK is triggered by regeneration of EBM with normal ultrastructure in the excimer laser- ablated zone. Conversely, incisional wounds heal in rabbit corneas without the development of myofibroblasts because the EBM regenerates normally by one month after surgery

  1. Analysis of excimer laser radiant exposure effect toward corneal ablation volume at LASIK procedure

    Adiati, Rima Fitria; Rini Rizki, Artha Bona; Kusumawardhani, Apriani; Setijono, Heru; Rahmadiansah, Andi

    2016-11-01

    LASIK (Laser Asissted In Situ Interlamelar Keratomilieusis) is a technique for correcting refractive disorders of the eye such as myopia and astigmatism using an excimer laser. This procedure use photoablation technique to decompose corneal tissues. Although preferred due to its efficiency, permanency, and accuracy, the inappropriate amount radiant exposure often cause side effects like under-over correction, irregular astigmatism and problems on surrounding tissues. In this study, the radiant exposure effect toward corneal ablation volume has been modelled through several processes. Data collecting results is laser data specifications with 193 nm wavelength, beam diameter of 0.065 - 0.65 cm, and fluence of 160 mJ/cm2. For the medical data, the myopia-astigmatism value, cornea size, corneal ablation thickness, and flap data are taken. The first modelling step is determining the laser diameter between 0.065 - 0.65 cm with 0.45 cm increment. The energy, power, and intensity of laser determined from laser beam area. Number of pulse and total energy is calculated before the radiant exposure of laser is obtained. Next is to determine the parameters influence the ablation volume. Regression method used to create the equation, and then the spot size is substituted to the model. The validation used is statistic correlation method to both experimental data and theory. By the model created, it is expected that any potential complications can be prevented during LASIK procedures. The recommendations can give the users clearer picture to determine the appropriate amount of radiant exposure with the corneal ablation volume necessary.

  2. Two cases of corneal perforation after oral administration of nonsteroidal anti-inflammatory drugs: oral NSAID-induced corneal damage.

    Masuda, Ikuya; Matsuo, Toshihiko; Okamoto, Kazuo; Matsushita, Kyoko; Ohtsuki, Hiroshi

    2010-01-01

    To report 2 cases of corneal perforation associated with the use of oral nonsteroidal anti-inflammatory drugs (NSAIDs). In a 62-year-old woman and a 79-year-old woman, corneal perforation occurred after 7 days and 5 months of oral NSAIDs administration, respectively. After NSAIDs were discontinued, the cornea epithelialized and the anterior chamber formed within 14 and 10 days, respectively. It is well known that topical NSAIDs cause corneal perforation. Observations in the present cases suggest that the oral administration of NSAIDs may also cause corneal damage, and hence, medical professionals should consider the risk of damage to the cornea when administering these drugs orally.

  3. Scanning laser polarimetry retinal nerve fiber layer thickness measurements after LASIK.

    Zangwill, Linda M; Abunto, Teresa; Bowd, Christopher; Angeles, Raymund; Schanzlin, David J; Weinreb, Robert N

    2005-02-01

    To compare retinal nerve fiber layer (RNFL) thickness measurements before and after LASIK. Cohort study. Twenty participants undergoing LASIK and 14 normal controls. Retinal nerve fiber layer thickness was measured before LASIK and approximately 3 months after surgery in one eye each of 20 patients using a scanning laser polarimeter (GDx Nerve Fiber Analyzer) with fixed corneal compensation (FCC), one with variable corneal compensation (GDx VCC), and optical coherence tomography (OCT). Fourteen normal controls also were tested at baseline and approximately 3 months later. Retinal nerve fiber layer thicknesses measured with the GDx FCC, GDx VCC, and OCT. At baseline, mean (95% confidence interval [CI]) RNFL thicknesses for the GDx FCC, GDx VCC, and OCT were 78.1 microm (72.2-83.9), 54.3 microm (52.7-56.0), and 96.8 microm (93.2-100.5), respectively. In both LASIK and control groups, there were no significant changes between baseline and follow-up examinations in GDx VCC and OCT RNFL thickness measurements globally or in the superior and inferior quadrants (mean change, FCC measurements between baseline and follow-up. In LASIK patients, significant reductions were observed in GDx FCC RNFL measurements. Average absolute values of the mean (95% CI) change in thickness were 12.4 microm (7.7-17.2), 15.3 microm (9.6-20.9), and 12.9 microm (7.6-18.1) for GDx FCC RNFL measurements superiorly, inferiorly, and globally, respectively (all Ps FCC RNFL thickness measurements after LASIK is a measurement artifact and is most likely due to erroneous compensation for corneal birefringence. With scanning laser polarimetry, it is mandatory to compensate individually for change in corneal birefringence after LASIK to ensure accurate RNFL assessment.

  4. Corneal donations in South Africa: A 15-year review.

    York, Nicholas J; Tinley, Christopher

    2017-07-28

    Corneal pathology is one of the leading causes of preventable blindness in South Africa (SA). A corneal transplant can restore or significantly improve vision in most cases. However, in SA there is a gross shortage of corneal tissue available to ophthalmologists. Little has been published describing the magnitude of the problem. To describe trends in the number of corneal donors per year in SA, the number of corneal transplants performed each year, the origin of donors, the allocation of corneas to the public or private sector, and the demographics of donors. This was a retrospective review of all corneal donations to SA eye banks over the 15-year period 1 January 2002 - 31 December 2016. There was a progressive year-on-year decline in corneal donors over the study period, from 565 per year in 2002 to 89 in 2016. As a direct result, there has been an 85.5% decrease in the number of corneal transplants performed per year using locally donated corneas, from 1 049 in 2002 to 152 in 2016. Of the donors, 48.8% originated from mortuaries, 39.0% from private hospitals and 12.2% from government hospitals; donors from mortuaries showed the most significant decline over the 15-year period, decreasing by 94.8%. Of donated corneas, 79.3% were allocated to the private sector and 21.7% to the public sector. Males comprised 69.1% of donors, while 77.2% were white, 14.0% coloured, 6.3% black and 2.5% Indian/Asian. Donor age demonstrated a bimodal peak at 25 and 55 years. The number of corneal donations in SA has declined markedly, causing the burden of corneal disease requiring transplantation to rise steadily. Population groups with a low donor rate may have cultural and other objections to corneal donation, which should be a major focus of future research and initiatives aimed at reversing the current trends.

  5. Adjuvant corneal crosslinking to prevent hyperopic LASIK regression.

    Aslanides, Ioannis M; Mukherjee, Achyut N

    2013-01-01

    To report the long term outcomes, safety, stability, and efficacy in a pilot series of simultaneous hyperopic laser assisted in situ keratomileusis (LASIK) and corneal crosslinking (CXL). A small cohort series of five eyes, with clinically suboptimal topography and/or thickness, underwent LASIK surgery with immediate riboflavin application under the flap, followed by UV light irradiation. Postoperative assessment was performed at 1, 3, 6, and 12 months, with late follow up at 4 years, and results were compared with a matched cohort that received LASIK only. The average age of the LASIK-CXL group was 39 years (26-46), and the average spherical equivalent hyperopic refractive error was +3.45 diopters (standard deviation 0.76; range 2.5 to 4.5). All eyes maintained refractive stability over the 4 years. There were no complications related to CXL, and topographic and clinical outcomes were as expected for standard LASIK. This limited series suggests that simultaneous LASIK and CXL for hyperopia is safe. Outcomes of the small cohort suggest that this technique may be promising for ameliorating hyperopic regression, presumed to be biomechanical in origin, and may also address ectasia risk.

  6. Adjuvant corneal crosslinking to prevent hyperopic LASIK regression

    Aslanides IM

    2013-03-01

    Full Text Available Ioannis M Aslanides, Achyut N MukherjeeEmmetropia Mediterranean Eye Clinic, Heraklion, Crete, GreecePurpose: To report the long term outcomes, safety, stability, and efficacy in a pilot series of simultaneous hyperopic laser assisted in situ keratomileusis (LASIK and corneal crosslinking (CXL.Method: A small cohort series of five eyes, with clinically suboptimal topography and/or thickness, underwent LASIK surgery with immediate riboflavin application under the flap, followed by UV light irradiation. Postoperative assessment was performed at 1, 3, 6, and 12 months, with late follow up at 4 years, and results were compared with a matched cohort that received LASIK only.Results: The average age of the LASIK-CXL group was 39 years (26–46, and the average spherical equivalent hyperopic refractive error was +3.45 diopters (standard deviation 0.76; range 2.5 to 4.5. All eyes maintained refractive stability over the 4 years. There were no complications related to CXL, and topographic and clinical outcomes were as expected for standard LASIK.Conclusion: This limited series suggests that simultaneous LASIK and CXL for hyperopia is safe. Outcomes of the small cohort suggest that this technique may be promising for ameliorating hyperopic regression, presumed to be biomechanical in origin, and may also address ectasia risk.Keyword: CXL

  7. Three-year changes in epithelial and stromal thickness after PRK or LASIK for high myopia.

    Ivarsen, Anders; Fledelius, Walther; Hjortdal, Jesper Ø

    2009-05-01

    To compare 3-year changes in corneal sublayer thickness after photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK). Forty-six patients with spheroequivalent refraction of -6.0 to -8.0 diopters (D) were randomly assigned to PRK or LASIK. One eye from each patient was included in the study. Examinations included manifest refraction and confocal microscopy through focusing (CMTF) and were performed preoperatively and postoperatively at 1 week and at 1, 3, 6, 12, and 36 months. From CMTF scans, the thicknesses of the central cornea (CT), epithelium (ET), stroma (ST), LASIK flap (FT), and residual stromal bed (BT) were calculated. After LASIK, spheroequivalent refraction averaged -0.76 D by 1 week and -1.19 D by 1 month, with no subsequent significant change. ET increased 9.0 +/- 7.0 microm within 1 week and remained constant thereafter. ST increased 12.9 +/- 9.4 microm within 1 year because of increased BT. One week after PRK, refraction averaged -0.23 D and stabilized at -1.42 D by 6 months. By 1 week, ET was reduced by 7.5 +/- 5.7 microm, reached preoperative thickness by 6 months, and increased further 7.3 +/- 6.0 microm by 3 years. ST increased 25.3 +/- 17.2 microm during 1 year, correlating with the postoperative refractive regression. After both procedures, changes in CT also correlated with refractive changes. No other correlations were identified. PRK and LASIK induce a persistent increase in ET that stabilizes 1 week after LASIK and 1 year after PRK. Stromal regrowth is most pronounced after PRK. After LASIK, regrowth is restricted to the residual stromal bed. Postoperative refractive changes correlate with changes in ST (PRK) and CT (PRK and LASIK) but not with changes in ET.

  8. Customized toric intraocular lens implantation for correction of extreme corneal astigmatism due to corneal scarring

    R Bassily

    2010-03-01

    Full Text Available R Bassily, J LuckOphthalmology Department, Royal United Hospital, Combe Park, Bath, UKAbstract: A 76-year-old woman presented with decreased visual function due to cataract formation. Twenty-five years prior she developed right sided corneal ulceration that left her with 10.8 diopters (D of irregular astigmatism at 71.8° (steep axis. Her uncorrected visual acuity was 6/24 and could only ever wear a balanced lens due to the high cylindrical error. Cataract surgery was planned with a custom designed toric intraocular lens (IOL with +16.0 D sphere inserted via a wound at the steep axis of corneal astigmatism. Postoperative refraction was -0.75/+1.50 × 177° with a visual acuity of 6/9 that has remained unchanged at six-week follow-up with no IOL rotation. This case demonstrates the value of high power toric IOLs for the correction of pathological corneal astigmatism.Keywords: intraocular lens, corneal ulceration, visual acuity, scarring

  9. Effects of genipin corneal crosslinking in rabbit corneas.

    Avila, Marcel Y; Narvaez, Mauricio; Castañeda, Juan P

    2016-07-01

    To evaluate the effect of genipin, a natural crosslinking agent, in rabbit eyes. Department of Ophthalmology, Universidad Nacional de Colombia Centro de Tecnologia Oftalmica, Bogotá, Colombia. Experimental study. Ex vivo rabbit eyes (16; 8 rabbits) were treated with genipin 1.00%, 0.50%, and 0.25% for 5 minutes with a vacuum device to increase corneal permeability. Penetration was evaluated using Scheimpflug pachymetry (Pentacam). In the in vivo model (20 rabbits; 1 eye treated, 1 eye with vehicle), corneas were crosslinked with genipin as described. Corneal curvature, corneal pachymetry, and intraocular pressure (IOP) assessments as well as slitlamp examinations were performed 0, 7, 30, and 60 days after treatment. In the ex vivo model, Scheimpflug pachymetry showed deep penetration in the rabbit corneas with an increase in corneal density and a dose-dependent relationship. Corneal flattening was observed in treated eyes (mean 4.4 diopters ± 0.5 [SD]) compared with the control eyes. Pachymetry and IOP were stable in all evaluations. No eye showed toxicity in the anterior chamber or in the lens. Corneal crosslinking induced by genipin produced significant flattening of the cornea with no toxicity in rabbit eyes. This crosslinking could be useful in the treatment of corneal ectasia and in the modification of corneal curvature. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  10. Crosslinking and corneal cryotherapy in acanthamoeba keratitis -- a histological study.

    Hager, Tobias; Hasenfus, A; Stachon, T; Seitz, B; Szentmáry, N

    2016-01-01

    Acanthamoeba keratitis is rare, but difficult to treat. Penetrating keratoplasty is performed in therapy-resistant cases. Nevertheless, subsequent recurrences occur in 40 % of the cases. In addition to triple-topical therapy (polyhexamid, propamidinisoethionat, neomycin), treatment alternatives are corneal cryotherapy and/or crosslinking (CXL). The aim of our present histological study was to analyze the persistence of acanthamoebatrophozoites and cysts, the persistence of bacteria, and activation of keratocytes in corneas of acanthamoeba keratitis patients following corneal cryotherapy and/or CXL. We analyzed histologically corneal buttons (from penetrating keratoplasties) of nine patients with acanthamoeba keratitis, following corneal cryotherapy (two patients) or a combination of crosslinking and corneal cryotherapy (seven patients), using haematoxilin–eosin, periodic acid Schiff (PAS), Gram and alpha-smooth muscle actin (alpha-SMA) stainings. Acanthamoeba trophozoites persisted in three corneas after cryotherapy and CXL. Cysts persisted in one of two corneas following corneal cryotherapy and in six of seven corneas after a combination of CXL and cryotherapy. One cornea showed positive Gram staining, but there were no alpha-SMA positive keratocytes in any of the corneas. Crosslinking and corneal cryotherapy have only limited impact on killing of acanthamoeba trophozoites, cysts, or bacteria. Corneal cryotherapy and CXL did not stimulate myofibroblastic transformation of keratocytes.

  11. 21 CFR 886.4070 - Powered corneal burr.

    2010-04-01

    ...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4070 Powered corneal burr. (a) Identification. A powered corneal burr is an AC-powered or battery-powered device that is a motor and drilling tool intended to remove rust rings from the cornea of the eye. (b) Classification. Class I (general controls). When...

  12. 21 CFR 886.1450 - Corneal radius measuring device.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Corneal radius measuring device. 886.1450 Section 886.1450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... corneal size by superimposing the image of the cornea on a scale at the focal length of the lens of a...

  13. In vivo human corneal hydration control dynamics: A new model

    Odenthal, M.T.P.; Nieuwendaal, C.P.; Venema, H.W.; Oosting, J.; Kok, J.H.C.; Kijlstra, A.

    1999-01-01

    PURPOSE. To introduce a new model describing human in vivo corneal deswelling after hypoxic contact lens wear, based on a damped harmonic oscillator, which can describe an overshoot in corneal deswelling, to compare this new model with the currently used exponential model, and also to test whether a

  14. In vivo human corneal hydration control dynamics: a new model

    Odenthal, M. T.; Nieuwendaal, C. P.; Venema, H. W.; Oosting, J.; Kok, J. H. C.; Kijlstra, A.

    1999-01-01

    PURPOSE: To introduce a new model describing human in vivo corneal deswelling after hypoxic contact lens wear, based on a damped harmonic oscillator, which can describe an overshoot in corneal deswelling, to compare this new model with the currently used exponential model, and also to test whether a

  15. Omega-3 supplementation is neuroprotective to corneal nerves in dry eye disease: a pilot study.

    Chinnery, Holly R; Naranjo Golborne, Cecilia; Downie, Laura E

    2017-07-01

    To investigate whether oral, long-chain omega-3 (ω-3) essential fatty acid (EFA) supplementation, for 3 months, induces changes to the central corneal sub-basal nerve plexus in dry eye disease and whether nerve alterations correlate with clinical findings. This prospective, comparative study involved the final 12 participants enrolled in a randomised, double-masked, placebo-controlled clinical trial of 60 participants with moderate dry eye disease. Participants received either placebo (olive oil 1500 mg/day; n = 4) or ω-3 EFA supplements (~1000 mg/day eicosapentaenoic acid + ~500 mg/day docosahexaenoic acid; n = 8) for 90 days. The main outcome measure was the mean change in central corneal sub-basal plexus nerve parameters between days one and 90, quantified using in vivo confocal microscopy. Secondary outcomes included mean change in tear osmolarity, corneal dendritic cell density and basal epithelial cell density. Compared with baseline, the reduction in OSDI score and tear osmolarity at day 90 were greater in the ω-3 EFA group than the placebo group (OSDI: ω-3 EFA, mean ± SEM: -15.6 ± 2.8 vs placebo: -2.8 ± 4.1 units, t 5 = 2.6, p = 0.04; tearosmolarity: ω-3 EFA: -22.63 ± 5.7 vs placebo: -8 ± 2.7 mOsmol/L, t 9 = 2.3, p = 0.04). At day 90, corneal total nerve branch density (CTBD: 91.1 ± 8.6 vs 45.1 ± 13.4 branches/mm 2 , F 1,10 = 14, p = 0.004) and corneal nerve branch density on the main fibre (CNBD: 63.4 ± 6.5 vs 27.9 ± 11.5 branches/mm 2 , F 1,10 = 6, p = 0.03) were higher in the ω-3 EFA group compared with placebo. Relative to day 1, CNBD (branches/mm 2 ) increased at day 90 in the ω-3 EFA group (+20.0 ± 9.2, t 8 = 3.2 p = 0.01) compared with placebo (-10.8 ± 3.2). Similar changes were evident for corneal nerve fibre length (CNFL, mm/mm 2 ), which increased from baseline at day 90 in the omega-3 EFA group (+2.9 ± 1.6, t 8 = 3.4 p = 0.01) compared with placebo (-2.7 ± 0.5). There was a negative correlation between CTBD and tear osmolarity

  16. Plasma polymer-coated contact lenses for the culture and transfer of corneal epithelial cells in the treatment of limbal stem cell deficiency.

    Brown, Karl David; Low, Suet; Mariappan, Indumathi; Abberton, Keren Maree; Short, Robert; Zhang, Hong; Maddileti, Savitri; Sangwan, Virender; Steele, David; Daniell, Mark

    2014-02-01

    Extensive damage to the limbal region of the cornea leads to a severe form of corneal blindness termed as limbal stem cell deficiency (LSCD). Whereas most cases of corneal opacity can be treated with full thickness corneal transplants, LSCD requires stem cell transplantation for successful ocular surface reconstruction. Current treatments for LSCD using limbal stem cell transplantation involve the use of murine NIH 3T3 cells and human amniotic membranes as culture substrates, which pose the threat of transmission of animal-derived pathogens and donor tissue-derived cryptic infections. In this study, we aimed to produce surface modified therapeutic contact lenses for the culture and delivery of corneal epithelial cells for the treatment of LSCD. This approach avoids the possibility of suture-related complications and is completely synthetic. We used plasma polymerization to deposit acid functional groups onto the lenses at various concentrations. Each surface was tested for its suitability to promote corneal epithelial cell adhesion, proliferation, retention of stem cells, and differentiation and found that acid-based chemistries promoted better cell adhesion and proliferation. We also found that the lenses coated with a higher percentage of acid functional groups resulted in a higher number of cells transferred onto the corneal wound bed in rabbit models of LSCD. Immunohistochemistry of the recipient cornea confirmed the presence of autologous, transplanted 5-bromo-2'-deoxyuridine (BrdU)-labeled cells. Hematoxylin staining has also revealed the presence of a stratified epithelium at 26 days post-transplantation. This study provides the first evidence for in vivo transfer and survival of cells transplanted from a contact lens to the wounded corneal surface. It also proposes the possibility of using plasma polymer-coated contact lenses with high acid functional groups as substrates for the culture and transfer of limbal cells in the treatment of LSCD.

  17. Surgically induced astigmatism after phacoemulsification by temporal clear corneal and superior clear corneal approach: a comparison

    Nikose AS

    2018-01-01

    Full Text Available Archana Sunil Nikose, Dhrubojyoti Saha, Pradnya Mukesh Laddha, Mayuri Patil Department of Ophthalmology, N.K.P. Salve Institute and LMH, Nagpur, Maharashtra, India Introduction: Cataract surgery has undergone various advances since it was evolved from ancient couching to the modern phacoemulsification cataract surgery. Surgically induced astigmatism (SIA remains one of the most common complications. The introduction of sutureless clear corneal incision has gained increasing popularity worldwide because it offers several advantages over the traditional sutured limbal incision and scleral tunnel. A clear corneal incision has the benefit of being bloodless and having an easy approach, but SIA is still a concern.Purpose: In this study, we evaluated the SIA in clear corneal incisions with temporal approach and superior approach phacoemulsification. Comparisons between the two incisions were done using keratometric readings of preoperative and postoperative refractive status.Methodology: It was a hospital-based prospective interventional comparative randomized control trial of 261 patients conducted in a rural-based tertiary care center from September 2012 to August 2014. The visual acuity and detailed anterior segment and posterior segment examinations were done and the cataract was graded according to Lens Opacification Classification System II. Patients were divided for phacoemulsification into two groups, group A and group B, who underwent temporal and superior clear corneal approach, respectively. The patients were followed up on day 1, 7, 30, and 90 postoperatively. The parameters recorded were uncorrected visual acuity, best-corrected visual acuity, slit lamp examination, and keratometry. The mean difference of SIA between 30th and 90th day was statistically evaluated using paired t-test, and all the analyses were performed using SPSS 18.0 (SPSS Inc. software.Results: The mean postoperative SIA in group A was 0.998 D on the 30th day, which

  18. A portable device for measuring donor corneal transparency in eye banks.

    Parekh, Mohit; Ferrari, Stefano; Ruzza, Alessandro; Pugliese, Mariarosaria; Ponzin, Diego; Salvalaio, Gianni

    2014-03-01

    To develop a portable device for measuring the donor corneal transparency and validate its efficacy for corneal evaluation in the eye-banks and for research. The transparency device (TD) has a light source, a detachable system for corneal insertion and a base for light transmission. The probe detects the transmitted light which is measured by a lux-meter. A contact lens was set as 'control' to reduce the light scattering concern, an empty petri-plate as 'blank' and the cornea as 'sample'. Two experts and non-experts (masked) observed the corneas for subjective analysis which was then compared using the TD. The parameters observed were scars, foreign-body, stromal-deformities, folds, thickness and opacity which were then converted to a relative overall percentage by the observer. Twenty corneas were evaluated for correlation, five tissues to obtain standard-deviation and twenty-four pairs for a comparative study. Experts mimicked the eye-banks with long-term experience while non-experts mimicked the emerging eye-banks. Subjective values by the experts closely resembled the measurements by TD. The average correlation between the experts and the non-experts to TD was 0.985 and 0.960 respectively. TD showed higher reproducibility than experts followed by the non-experts. The comparative study showed that increase in thickness reduces the transparency. TD is portable, easy, efficient, maintains sterility and less expensive hence the emerging eye-banks and researchers can use to raise their standards and evaluate the transparency for in vitro tests and comparative studies. The suitable transparency for the cornea deemed for clinical applications was found to be >75 %.

  19. Bioactive self-assembled peptide nanofibers for corneal stroma regeneration.

    Uzunalli, G; Soran, Z; Erkal, T S; Dagdas, Y S; Dinc, E; Hondur, A M; Bilgihan, K; Aydin, B; Guler, M O; Tekinay, A B

    2014-03-01

    Defects in the corneal stroma caused by trauma or diseases such as macular corneal dystrophy and keratoconus can be detrimental for vision. Development of therapeutic methods to enhance corneal regeneration is essential for treatment of these defects. This paper describes a bioactive peptide nanofiber scaffold system for corneal tissue regeneration. These nanofibers are formed by self-assembling peptide amphiphile molecules containing laminin and fibronectin inspired sequences. Human corneal keratocyte cells cultured on laminin-mimetic peptide nanofibers retained their characteristic morphology, and their proliferation was enhanced compared with cells cultured on fibronectin-mimetic nanofibers. When these nanofibers were used for damaged rabbit corneas, laminin-mimetic peptide nanofibers increased keratocyte migration and supported stroma regeneration. These results suggest that laminin-mimetic peptide nanofibers provide a promising injectable, synthetic scaffold system for cornea stroma regeneration. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Automated Decision Tree Classification of Corneal Shape

    Twa, Michael D.; Parthasarathy, Srinivasan; Roberts, Cynthia; Mahmoud, Ashraf M.; Raasch, Thomas W.; Bullimore, Mark A.

    2011-01-01

    Purpose The volume and complexity of data produced during videokeratography examinations present a challenge of interpretation. As a consequence, results are often analyzed qualitatively by subjective pattern recognition or reduced to comparisons of summary indices. We describe the application of decision tree induction, an automated machine learning classification method, to discriminate between normal and keratoconic corneal shapes in an objective and quantitative way. We then compared this method with other known classification methods. Methods The corneal surface was modeled with a seventh-order Zernike polynomial for 132 normal eyes of 92 subjects and 112 eyes of 71 subjects diagnosed with keratoconus. A decision tree classifier was induced using the C4.5 algorithm, and its classification performance was compared with the modified Rabinowitz–McDonnell index, Schwiegerling’s Z3 index (Z3), Keratoconus Prediction Index (KPI), KISA%, and Cone Location and Magnitude Index using recommended classification thresholds for each method. We also evaluated the area under the receiver operator characteristic (ROC) curve for each classification method. Results Our decision tree classifier performed equal to or better than the other classifiers tested: accuracy was 92% and the area under the ROC curve was 0.97. Our decision tree classifier reduced the information needed to distinguish between normal and keratoconus eyes using four of 36 Zernike polynomial coefficients. The four surface features selected as classification attributes by the decision tree method were inferior elevation, greater sagittal depth, oblique toricity, and trefoil. Conclusions Automated decision tree classification of corneal shape through Zernike polynomials is an accurate quantitative method of classification that is interpretable and can be generated from any instrument platform capable of raw elevation data output. This method of pattern classification is extendable to other classification