The Effect of Various Contact Lenses on Intraocular Pressure Measurement by Goldman Tonometer

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Monireh Mahjoob

2014-06-01

Full Text Available Background: Today, contact lenses have extensive usages. Contact lens places on cornea, so it may induce variation on cornea and these variations can influence the measurement of intraocular pressure (IOP by Goldman tonometer. The aim of this research was to study the effect of various contact lenses on measurement of intraocular pressure by Goldman tonometer. Materials and Methods: In this study, 80 subjects aged 18-25 were selected randomly among patients of Al-Zahra ophthalmology center. None of them has any eye pathological problems. Before wearing the lens, intraocular pressure was measured, and then patients were divided into two groups of soft and hard contact lenses. Soft and hard contact lenses were placed on the eye for two hours, and the intraocular pressure was measured again. Results: The mean of IOP before wearing contact lenses and two hours later was 15.96 mmHg and 13.93, s respectively. Paired test showed a significant difference between IOP before and after wearing contact lenses (p=0.001.There was no significant differences in mean of intraocular pressure decline before and after placing the contact lens in both soft and hard lenses. Conclusion: According to this study, the intraocular pressure decreases after wearing contact lenses (CL. This decline may be due to variation in properties of cornea after wearing CL that can also affect IOP measurement.

Intraocular Pressure Increases After Intraarticular Knee Injection With Triamcinolone but Not Hyaluronic Acid.

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Taliaferro, Kevin; Crawford, Alexander; Jabara, Justin; Lynch, Jonathan; Jung, Edward; Zvirbulis, Raimonds; Banka, Trevor

2018-03-09

Intraarticular steroid injections are a common first-line therapy for severe osteoarthritis, which affects an estimated 27 million people in the United States. Although topical, oral, intranasal, and inhalational steroids are known to increase intraocular pressure in some patients, the effect of intraarticular steroid injections on intraocular pressure has not been investigated, to the best of our knowledge. If elevated intraocular pressure is sustained for long periods of time or is of sufficient magnitude acutely, permanent loss of the visual field can occur. How does intraocular pressure change 1 week after an intraarticular knee injection either with triamcinolone acetonide or hyaluronic acid? A nonrandomized, nonblinded prospective cohort study was conducted at an outpatient, ambulatory orthopaedic clinic. This study compared intraocular pressure elevation before and 1 week after intraarticular knee injection of triamcinolone acetonide versus hyaluronic acid for management of primary osteoarthritis of the knee. Patients self-selected to be injected in their knee with either triamcinolone acetonide or hyaluronic acid before being informed of the study. The primary endpoint was intraocular pressure elevation of ≥ 7 mm Hg 1 week after injection. This cutoff is determined as the minimum significant pressure change in the ophthalmology literature recognized as an intermediate responder to steroids. Intraocular pressure was measured using a handheld Tono-Pen® applanation device. This device is frequently used in intraocular pressure measurement in clinical and research settings; 10 sequential measurements are obtained and averaged with a confidence interval. Only measurements with a 95% confidence interval were used. Over a 6-month period, a total of 96 patients were approached to enroll in the study. Sixty-two patients out of 96 approached (65%) agreed. Thirty-one (50%) were injected with triamcinolone and 31 (50%) were injected with hyaluronic acid. Patients

Intraocular pressure measurement: Goldmann Applanation Tonometer vs non contact airpuff tonometer.

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Shah, Masood Alam; Bin Saleem, Khalid; Mehmood, Talat

2012-01-01

An accurate assessment of Intraocular pressure (IOP) is vital in establishing diagnosis of Glaucoma and decision making regarding various treatment modalities available. The purpose of this study is to compare Goldmann Applanation Tonometer (GAT) with Air puff tonometer. Cross-sectional comparative study conducted. 73 eyes from 73 patients were included in this study and intraocular pressure (IOP) was measured by GAT and PT100 at Sheikh Khalifa Bin Zayed Hospital, Muzaffarabad, Benazir Shaheed Teaching Hospital, Abbottabad. Mean age of the patients was 53.17 +/- 13.80 years. Mean IOP measurements showed significant differences in measurements performed by the two tonometers (p contact air-puff tonometer, the Goldmann applanation tonometer is a reliable and consistent technique for measurement of intraocular pressure.

The effect of intraocular gas and fluid volumes on intraocular pressure.

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Simone, J N; Whitacre, M M

1990-02-01

Large increases in the intraocular pressure (IOP) of postoperative gas-containing eyes may require the removal of gas or fluid to reduce the IOP to the normal range. Application of the ideal gas law to Friedenwald's equation provides a mathematical model of the relationship between IOP, intraocular gas and fluid volumes, and the coefficient of scleral rigidity. This mathematic model shows that removal of a given volume of gas or fluid produces an identical decrease in IOP and that the more gas an eye contains, the greater the volume reduction necessary to reduce the pressure. Application of the model shows that the effective coefficient of scleral rigidity is low (mean K, 0.0021) in eyes with elevated IOP that have undergone vitrectomy and retinal cryopexy and very low (mean K, 0.0013) in eyes with elevated IOP that have undergone placement of a scleral buckle and band. By using the appropriate mean coefficient of rigidity, the volume of material to be aspirated to produce a given decrease in IOP can be predicted with clinically useful accuracy.

Evaluating the risk of eye injuries: intraocular pressure during high speed projectile impacts.

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Duma, Stefan M; Bisplinghoff, Jill A; Senge, Danielle M; McNally, Craig; Alphonse, Vanessa D

2012-01-01

To evaluate the risk of eye injuries by determining intraocular pressure during high speed projectile impacts. A pneumatic cannon was used to impact eyes with a variety of projectiles at multiple velocities. Intraocular pressure was measured with a small pressure sensor inserted through the optic nerve. A total of 36 tests were performed on 12 porcine eyes with a range of velocities between 6.2 m/s and 66.5 m/s. Projectiles selected for the test series included a 6.35  mm diameter metal ball, a 9.25  mm diameter aluminum rod, and an 11.16  mm diameter aluminum rod. Experiments were designed with velocities in the range of projectile consumer products such as toy guns. A range of intraocular pressures ranged between 2017 mmHg to 26,426 mmHg (39 psi-511 psi). Four of the 36 impacts resulted in globe rupture. Intraocular pressures dramatically above normal physiological pressure were observed for high speed projectile impacts. These pressure data provide critical insight to chronic ocular injuries and long-term complications such as glaucoma and cataracts.

Ocular onchocerciasis in the Yanomami communities from Brazilian Amazon: effects on intraocular pressure.

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Herzog-Neto, Guilherme; Jaegger, Karen; Nascimento, Erika S do; Marchon-Silva, Verônica; Banic, Dalma M; Maia-Herzog, Marilza

2014-01-01

To determine the influence of onchocercal eye disease on the intraocular pressure of the Yanomami Tribe Aratha-ú of Roraima State, Brazil, considered endemic for onchocerciasis, a total of 86 patients were submitted to an ophthalmologic exam that included external examination, slit lamp examination, intraocular pressure measurement, and a fundus ophthalmoscope examination. A high prevalence of onchocerciasis-related eye lesions was encountered in 68.6% of the patients. Punctate keratitis and microfilariae in the anterior chamber were found in ∼28%. The mean of intraocular eye pressure found was 10.47 mm of Hg.

[Effects of acupuncture on circadian rhythm of blood pressure in patients with essential hypertension].

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Lei, Yun; Jin, Jiu; Ban, Haipeng; Du, Yuzheng

2017-11-12

To observe the effects of acupuncture combined with medication on circadian rhythm of blood pressure in patients with essential hypertension. Sixty-four patients of essential hypertension were randomly divided into an observation group and a control group, 32 cases in each group. All the patients maintained original treatment (taking antihypertensive medication); the patients in the observation group were treated with acupuncture method of " Huoxue Sanfeng , Shugan Jianpi ", once a day, five times per week, for totally 6 weeks (30 times). The circadian rhythm of blood pressure and related dynamic parameters were observed before and after treatment in the two groups. (1) The differences of daytime average systolic blood pressure (dASBP), daytime average diastolic blood pressure (dADBP), nighttime average systolic blood pressure (nASBP) and circadian rhythm of systolic blood pressure before and after treatment were significant in the observation group (all P circadian rhythm of blood pressure and related dynamic parameters before and after treatment were insignificant in the control group (all P >0.05). The nASBP and circadian rhythm of systolic blood pressure in the observation group were significantly different from those in the control group (all P circadian rhythm of blood pressure in the observation group was higher than that in the control group ( P circadian rhythm of blood pressure and related dynamic parameters in patients with essential hypertension.

The effect of increased intra-abdominal pressure on orbital subarachnoid space width and intraocular pressure.

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Liu, Su-Meng; Wang, Ning-Li; Zuo, Zhen-Tao; Chen, Wei-Wei; Yang, Di-Ya; Li, Zhen; Cao, Yi-Wen

2018-02-01

In accordance with the trans-lamina cribrosa pressure difference theory, decreasing the trans-lamina cribrosa pressure difference can relieve glaucomatous optic neuropathy. Increased intracranial pressure can also reduce optic nerve damage in glaucoma patients, and a safe, effective and noninvasive way to achieve this is by increasing the intra-abdominal pressure. The purpose of this study was to observe the changes in orbital subarachnoid space width and intraocular pressure at elevated intra-abdominal pressure. An inflatable abdominal belt was tied to each of 15 healthy volunteers, aged 22-30 years (12 females and 3 males), at the navel level, without applying pressure to the abdomen, before they laid in the magnetic resonance imaging machine. The baseline orbital subarachnoid space width around the optic nerve was measured by magnetic resonance imaging at 1, 3, 9, and 15 mm behind the globe. The abdominal belt was inflated to increase the pressure to 40 mmHg (1 mmHg = 0.133 kPa), then the orbital subarachnoid space width was measured every 10 minutes for 2 hours. After removal of the pressure, the measurement was repeated 10 and 20 minutes later. In a separate trial, the intraocular pressure was measured for all the subjects at the same time points, before, during and after elevated intra-abdominal pressure. Results showed that the baseline mean orbital subarachnoid space width was 0.88 ± 0.1 mm (range: 0.77-1.05 mm), 0.77 ± 0.11 mm (range: 0.60-0.94 mm), 0.70 ± 0.08 mm (range: 0.62-0.80 mm), and 0.68 ± 0.08 mm (range: 0.57-0.77 mm) at 1, 3, 9, and 15 mm behind the globe, respectively. During the elevated intra-abdominal pressure, the orbital subarachnoid space width increased from the baseline and dilation of the optic nerve sheath was significant at 1, 3 and 9 mm behind the globe. After decompression of the abdominal pressure, the orbital subarachnoid space width normalized and returned to the baseline value. There was no significant difference in the

Dysglycemia induces abnormal circadian blood pressure variability

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Kumarasamy Sivarajan

2011-11-01

Full Text Available Abstract Background Prediabetes (PreDM in asymptomatic adults is associated with abnormal circadian blood pressure variability (abnormal CBPV. Hypothesis Systemic inflammation and glycemia influence circadian blood pressure variability. Methods Dahl salt-sensitive (S rats (n = 19 after weaning were fed either an American (AD or a standard (SD diet. The AD (high-glycemic-index, high-fat simulated customary human diet, provided daily overabundant calories which over time lead to body weight gain. The SD (low-glycemic-index, low-fat mirrored desirable balanced human diet for maintaining body weight. Body weight and serum concentrations for fasting glucose (FG, adipokines (leptin and adiponectin, and proinflammatory cytokines [monocyte chemoattractant protein-1 (MCP-1 and tumor necrosis factor-α (TNF-α] were measured. Rats were surgically implanted with C40 transmitters and blood pressure (BP-both systolic; SBP and diastolic; DBP and heart rate (HR were recorded by telemetry every 5 minutes during both sleep (day and active (night periods. Pulse pressure (PP was calculated (PP = SBP-DBP. Results [mean(SEM]: The AD fed group displayed significant increase in body weight (after 90 days; p Conclusion These data validate our stated hypothesis that systemic inflammation and glycemia influence circadian blood pressure variability. This study, for the first time, demonstrates a cause and effect relationship between caloric excess, enhanced systemic inflammation, dysglycemia, loss of blood pressure control and abnormal CBPV. Our results provide the fundamental basis for examining the relationship between dysglycemia and perturbation of the underlying mechanisms (adipose tissue dysfunction induced local and systemic inflammation, insulin resistance and alteration of adipose tissue precursors for the renin-aldosterone-angiotensin system which generate abnormal CBPV.

Changes of intraocular pressure in different trimesters of pregnancy among Syrian refugees in Turkey: A cross-sectional study.

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Tolunay, Harun Egemen; Özcan, Sait Coşkun; Şükür, Yavuz Emre; Özarslan Özcan, Deniz; Adıbelli, Fatih Mehmet; Hilali, Neşe Gül

2016-06-01

To evaluate the physiologic changes in intraocular pressure associated with pregnancy in healthy Syrian refugee women in Turkey. In this cross-sectional study, intraocular pressures were measured using a Goldmann tonometer in 235 patients in the first, second, and third trimester of pregnancy and puerperium among Syrian refugees in Turkey. Mean intraocular pressures values of the right eye were 15.5±2.5 mmHg, 14.4±1.4 mmHg, 13.9±1.6 and 14.7±1.9 mmHg in the three trimesters and puerperium, respectively. Mean intraocular pressures values of the left eye were 15.3±1.6 mmHg, 14.3±1.4 mmHg, 13.9±1.6 and 15.3±2.2 mmHg in the three trimesters and puerperium, respectively. The mean intraocular pressures values measured from both eyes were significantly higher in first trimester and puerperal period than in the third trimester (p<0.001). Changes in the intraocular pressure in pregnancy are common and temporary. This study shows the baseline changes in the intraocular pressure during pregnancy in healthy women. Therefore, we cannot extrapolate the results to the whole eye. A decrease in intraocular pressures was shown in healthy pregnant women.

[Contemporary possibilities of intraocular pressure measurement].

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Hornová, J; Baxant, A

2013-10-01

Authors introduced current possibilities of measuring intraocular pressure (IOP). A list of available methods of monitoring IOP is published; contact measurement method IOP directly on the cornea, but also over upper lid, methodology of minimal contact and non-contact measurement. Following contact methods are described; former measurements of IOP by impression Schiotz tonometer and the current methodology applanation. So far as the gold standard measurement Goldmann applanation tonometer (GAT) is considered, another methodology with applanation measurements are compared: Pascal dynamic contoured tonometer (DCT ), BioResonator - resonant applanation tonometer (ART ), digital applanation tonometer Tonopen and last hit: continuous measurement of IOP by Sensimed Triggerfish. Orientation and rapid assessment is palpation pressure control over the lid and measuring by tonometer Diaton. Rebound tonometer (RBT) iCare belongs to measurements with minimal contact, no need anesthetic drops and fluorescein, therefore a self - home version of IOP measurements (Icare ONE) is developed. Non-contact measurement of IOP by different pneumotonometers is popular for screening assessment of IOP. Reichert Ocular Response Analyzer (ORA) is a non-contact applanation IOP measurement and reveals additional properties of the cornea. In the discussion of a range methodology is evaluated, the experience of other authors and their own experience is compared. For monitoring of patients is necessary to select the most suitable methodology, measure repeatedly and accurately to allow long-term monitoring of intraocular pressure.

Apparatus and method for non-contact, acoustic resonance determination of intraocular pressure

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Sinha, D.N.; Wray, W.O.

1994-12-27

The apparatus and method for measuring intraocular pressure changes in an eye under investigation by detection of vibrational resonances therein. An ultrasonic transducer operating at its resonant frequency is amplitude modulated and swept over a range of audio frequencies in which human eyes will resonate. The output therefrom is focused onto the eye under investigation, and the resonant vibrations of the eye observed using a fiber-optic reflection vibration sensor. Since the resonant frequency of the eye is dependent on the pressure therein, changes in intraocular pressure may readily be determined after a baseline pressure is established. 3 figures.

Intraocular pressure menagement with transpalpebral tonometry

OpenAIRE

Toker, Mustafa İlker; Dursun, Ayhan

2013-01-01

Applanation tonometry is the method of measuring intraocular pressure (IOP) with instruments the corneal surface. The Goldmann applanation tonometer (GAT) is regarded as the “gold standard’’ of measuring IOP. An irregular and opaque corneal surface compromises IOP measurement by Goldmann applanation tonometry. In such cases accurate measurement without corneal contact would be applicable. The transpalpebral tonometer is new method and measures IOP without corneal contact through the eyelid....

Circadian pattern of blood pressure in normal pregnancy and preeclampsia.

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Gupta, Hem Prabha; Singh, R K; Singh, Urmila; Mehrotra, Seema; Verma, N S; Baranwal, Neelam

2011-08-01

AIMS #ENTITYSTARTX00026; To find out the circadian pattern of blood pressure in normotensive pregnant women and in women with preeclampsia. A cross-sectional prospective observational case control study. Blood pressure was sampled in thirty-five normotensive pregnant women (control) and thirty five preeclamptic women (study group) by using non-invasive automatic ambulatory blood pressure monitoring machine for 72 h. Blood pressure (BP) was not constant over 24 h period and it oscillated from time to time in control group. BP was maximum during early part of afternoon. However, in preeclampsia besides quantitative increase in BP, circadian BP oscillations were less pronounced and in around 50% subjects BP was maximum during evening and night hours. Both systolic and diastolic BP showed definite reproducible circadian pattern in both preeclamptic and normotensive pregnant women. This pattern both quantitatively and qualitatively was different in preeclamptic women. Standardized 24 h BP monitoring allows quantitative and qualitative evaluation of hypertensive status and is important for timing and dosing of antihypertensive medications.

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

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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.

Foldable micro coils for a transponder system measuring intraocular pressure

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Ullerich, S.; Schnakenberg, U. [Technische Hochschule Aachen (Germany). Inst. of Materials in Electrical Engineering 1; Mokwa, W. [Technische Hochschule Aachen (Germany). Inst. of Materials in Electrical Engineering 1]|[Fraunhofer Inst. of Microelectronic Circuits and Systems, Duisburg (Germany); Boegel, G. vom [Fraunhofer Inst. of Microelectronic Circuits and Systems, Duisburg (Germany)

2001-07-01

A foldable transponder system consisting of a chip and a micro coil for measuring intraocular pressure continuously is presented. The system will be integrated in the haptic of a soft artificial intraocular lens. Calculations of planar micro coils with 6 mm and 10.3 mm in diameter show the limits for planar coils with an outer diameter of 6 mm. For the realisation of the transponder system a 20 {mu}m thick coil with an outer diameter of 10.3 mm, an inner diameter of 7.7 mm, 16 turns and a gap of 20 {mu}m between the windings was selected. Measurements show a good agreement between calculated and measured values. Wireless pressure measurements were carried out showing a linear behaviour of the output signal with respect to the applied pressure. (orig.)

Corn silk aqueous extracts and intraocular pressure of systemic and non-systemic hypertensive subjects.

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George, Gladys O; Idu, Faustina K

2015-03-01

Hypotensive properties have been attributed to the stigma/style of Zea mays L (corn silk). Although the effect of corn silk extract on blood pressure has been documented in animal studies, we are not aware of any study on its effect on human blood pressure and intraocular pressure. A randomised study was carried out on the effect of water only, masked doses of corn silk aqueous extract (60, 130, 192.5 and 260 mg/kg body weight) on intraocular pressure and blood pressure of 20 systemic and 20 non-systemic hypertensive subjects. Intraocular pressure and blood pressure were measured at baseline and every hour for eight hours after administering water or a masked dose of corn silk aqueous extract. Each dose was administered at two-week intervals to each subject in the two study groups. The results showed that the last three doses of corn silk aqueous extract gave a statistically significant reduction (p Corn silk aqueous extract has a lowering effect on intraocular pressure in systemic and non-systemic hypertensive subjects. This may have resulted from the fall in blood pressure that is due to potassium-induced natriuresis and diuresis caused by the high potassium content in the high doses of the corn silk extract. © 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.

Changes in intraocular pressure and horizontal pupil diameter ...

African Journals Online (AJOL)

The objective of this study was to determine the effects of topical 0.5% tropicamide, 1% atropine sulphate and 10% phenylephrine hydrochloride ophthalmic solutions on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the dog during the first hour after treatment. Forty clinically and ophthalmologically ...

[Hormonal homeostasis and intraocular pressure in chronic emotional stress caused by influences acting on the amygdala].

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Isakova, L S; Danilov, G E; Egorkina, S B; Butolin, E G

1989-01-01

Changes in intraocular pressure, eye hydrodynamics and the amount of hypophyseal, thyroid, adrenal and pancreatic hormones were studied during continuous stimulation of amygdaloid complex or after administration of angiotensin II into the structure in rabbits. The effects involved changes in hormonal homeostasis and elevation of intraocular pressure due to a hypersecretion of intraocular fluid. The administration of angiotensin II during the amygdala stimulation enhanced the changes.

Ocular Onchocerciasis in the Yanomami Communities from Brazilian Amazon: Effects on Intraocular Pressure

OpenAIRE

Herzog-Neto, Guilherme; Jaegger, Karen; do Nascimento, Erika S.; Marchon-Silva, Verônica; Banic, Dalma M.; Maia-Herzog, Marilza

2014-01-01

To determine the influence of onchocercal eye disease on the intraocular pressure of the Yanomami Tribe Aratha-ú of Roraima State, Brazil, considered endemic for onchocerciasis, a total of 86 patients were submitted to an ophthalmologic exam that included external examination, slit lamp examination, intraocular pressure measurement, and a fundus ophthalmoscope examination. A high prevalence of onchocerciasis-related eye lesions was encountered in 68.6% of the patients. Punctate keratitis and ...

Intraocular Pressure in Pregnant and Non-Pregnant Nigerian Women

African Journals Online (AJOL)

Erah

. ... ocular diseases and these were used as the exclusion ... between groups with student's t-test. ... SD = standard deviation, SEM = standard error of mean, N= .... 38(4):229-34. 26. Qureshi IA. Intraocular pressure and pregnancy. Clin. Med.

Clinical analysis of modified trabeculectomy in glaucoma surgery with high elevated intraocular pressure

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Cang-Xia Zhang

2013-10-01

Full Text Available AIM: To make a retrospective analysis of the clinical data of modified trabeculectomy in treating glaucoma surgery with high elevated intraocular pressure retrospectively and evaluate the effect of modified trabeculectomy.METHODS:One hundred acute angle-closure glaucoma patients(100 eyeswith persistent high intraocular pressure were divided into treatment group(45 eyesand control group(55 eyes. Patients in treatment group was treated with by trabeculectomy, while those in control group received modified trabeculectomy. The modified measures include stellate ganglion block preoperative, topical anesthesia and local anesthesia with 20g/L lidocaine cotton-piece, to make scleral flap with sclerotome, to release aqueous humor outflow slowly after paracentesis of anterior chamber, and using mydriatic and cycloplegic during and after surgery.RESULTS: The incidence of operation complicationin control group was lower than that in treatment group. The differences were statistically significant(Pt=9.1535, Pt=39.8010, Pt=11.3219, PCONCLUSION: The modified trabeculectomy applied in the treatment of glaucoma with persistent high intraocular pressure can not only save the visual function of connection part to a certain extent, but also reduce the incidence of serious complications. It can obtain better intraocular pressure, shorten the average hospitalization days, decrease the expenses and increase patients satisfaction.

A noncontact intraocular pressure measurement device using a micro reflected air pressure sensor for the prediagnosis of glaucoma

International Nuclear Information System (INIS)

Kim, Kyoung Hwan; Kim, Byeong Hee; Seo, Young Ho

2012-01-01

This study investigates a novel, portable tonometer using a micro reflected air pressure sensor for the prediagnosis of glaucoma. Because glaucoma progresses slowly and is not painful, glaucoma patients require a portable prediagnosis system to periodically measure intraocular pressure at home. Conventionally, intraocular pressure is measured by an air-puff tonometer whereby the cornea is deformed by a short pulse of air pressure and the magnitude of the corneal deformation is measured by optic systems such as a combination of laser- and photodiodes. In this study, a micro reflected air pressure sensor was designed, fabricated, and tested in order to measure the magnitude of corneal deformation without optic systems. In an experimental study, artificial eyes with different internal pressures were fabricated and these pressures were measured by the aforementioned system. (paper)

Regulation of circadian blood pressure: from mice to astronauts.

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Agarwal, Rajiv

2010-01-01

Circadian variation is commonly seen in healthy people; aberration in these biological rhythms is an early sign of disease. Impaired circadian variation of blood pressure (BP) has been shown to be associated with greater target organ damage and with an elevated risk of cardiovascular events independent of the BP load. The purpose of this review is to examine the physiology of circadian BP variation and propose a tripartite model that explains the regulation of circadian BP. The time-keeper in mammals resides centrally in the suprachiasmatic nucleus. Apart from this central clock, molecular clocks exist in most peripheral tissues including vascular tissue and the kidney. These molecular clocks regulate sodium balance, sympathetic function and vascular tone. A physiological model is proposed that integrates our understanding of molecular clocks in mice with the circadian BP variation among humans. The master regulator in this proposed model is the sleep-activity cycle. The equivalents of peripheral clocks are endothelial and adrenergic functions. Thus, in the proposed model, the variation in circadian BP is dependent upon three major factors: physical activity, autonomic function, and sodium sensitivity. The integrated consideration of physical activity, autonomic function, and sodium sensitivity appears to explain the physiology of circadian BP variation and the pathophysiology of disrupted BP rhythms in various conditions and disease states. Our understanding of molecular clocks in mice may help to explain the provenance of blunted circadian BP variation even among astronauts.

Circadian melatonin concentration rhythm is lost in pregnant women with altered blood pressure rhythm.

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Tranquilli, A L; Turi, A; Giannubilo, S R; Garbati, E

2004-03-01

We assessed the correlation between the rhythm of melatonin concentration and circadian blood pressure patterns in normal and hypertensive pregnancy. Ambulatory 24-h blood pressure and blood samples every 4 h were monitored in 16 primigravidae who had shown an abnormal circadian blood pressure pattern (eight pre-eclamptic and eight normotensive) in pregnancy and 6-12 months after pregnancy. The circadian rhythm was analyzed by chronobiological measures. Eight normotensive women with maintained blood pressure rhythm served as controls. During pregnancy, melatonin concentration was significantly higher in pre-eclamptic than in normotensive women (pre-eclampsia, 29.4 +/- 1.9 pg/ml, normotensin, altered rhythm, 15.6 +/- 2.1; controls, 22.7 +/- 1.8; p lost in all pregnant women with loss of blood pressure rhythm. After pregnancy, normotensive women showed a reappearance of both melatonin and blood pressure rhythm, whereas pre-eclamptic women showed a reappearance of blood pressure but not melatonin rhythm. The loss of blood pressure rhythm in pregnancy is consistent with the loss of melatonin concentration rhythm. In pre-eclamptic women, the normalization of blood pressure rhythm, while melatonin rhythm remained altered, suggests a temporal or causal priority of circadian concentration of melatonin in the determination of blood pressure trend.

Influence of gross saponins from tribulus terrestris L on SOD activity and MDA content for chronic high intraocular pressure in rabbit

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Nuo Li

2013-05-01

Full Text Available AIM:To observe influence of gross saponins from tribulus terrestris L(GSTTon SOD activity and MDA content for chronic high intraocular pressure in rabbit, and discusses the retina oxidative damage inhibition on chronic high intraocular pressure model of rabbit. METHODS:Totally 24 healthy New Zealand rabbits were randomly divided into 4 groups: normal control group(A group; high intraocular pressure model blank group(B group; high intraocular pressure model with GSTT treated group(C group; high intraocular pressure model with Erigeron brevicapas hand mass(EBHMtreated group(D group. High intraocular pressure model was induced by 20g/L methylcellulose injection into the anterior chamber in B group, C group and D group. D group was injected 5 mg/kg GSTT and C group was injected 4.5mg/kg EBHM and measured intraocular pressure with Schiotz tonometer every day for 4 weeks. The retina tissue superoxide dismutase(SODand maleic dialdehyde(MDAcontent were detected 28 days later. RESULTS: After glaucoma model of rabbit eyes were established, the intraocular pressure during observation period was maintained in 32-39mmHg; High intraocular pressure model blank group and normal control group, EBHM treatment group, GSTT treatment group were compared, the differences of retina MDA, SOD content had statistical significance(P0.05; EBHM treatment group, GSTT treatment group and normal control group were compared, the content of MDA in the retina was still slightly higher(P<0.05, the content of SOD slightly lower(P<0.05 CONCLUSION: GSTT can effectively improve the retina SOD activity of chronic high intraocular pressure in rabbit and reduce the content of MDA, which has a protective effect of persistent high intraocular retinal oxidative stress.

Intraocular pressure-lowering effect of oral paracetamol and its in vitro corneal penetration properties

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Mohamed N

2013-01-01

Full Text Available Nabiel Mohamed, David MeyerDivision of Ophthalmology, Faculty of Medicine and Health Sciences, University of Stellenbosch, Cape Town, South AfricaBackground: Several studies have confirmed the ability of cannabinoids to reduce intraocular pressure. Experimental data recently demonstrated unequivocally that the analgesic effect of paracetamol is due to its indirect action on cannabinoid receptors. The question then arises as to whether paracetamol can reduce intraocular pressure via its effect on intraocular cannabinoid receptors.Methods: A 2-week, prospective, randomized, controlled, single-center, parallel-group pilot study was carried out to determine the efficacy and safety of paracetamol 1 g orally administered every 6 hours in adult patients with primary or secondary open angle glaucoma as compared with topical levobunolol 0.5% twice a day. Patient well-being was closely monitored throughout the study and focused on hepatic safety in accordance with Drug-Induced Liver Injury Network criteria. The in vitro diffusion kinetics of acetaminophen in a phosphate-buffered solution in rabbit and human corneas was also investigated, with the view to a topical application.Results: Eighteen adult patients were enrolled in the study, with nine in the topical levobunolol group and nine in the oral paracetamol group. In the levobunolol group, the mean reduction in intraocular pressure at day 7 was 7.5 mmHg (P < 0.008 and at day 14 was 9.1 mmHg (P < 0.005, from a mean baseline intraocular pressure of 29.6 mmHg. The corresponding figures for the paracetamol group were 8.8 mmHg (P < 0.0004 at day 7 and 6.5 mmHg (P < 0.004 at day 14, from a mean baseline intraocular pressure of 29.4 mmHg. Both study regimens were well tolerated. No serious treatment-related adverse events were reported in either of the treatment groups. Liver function tests, systolic/diastolic blood pressure, or heart rate remained unchanged in both groups during the 2 weeks of the study. In

Evaluation of the diurnal intraocular pressure fluctuations and blood pressure under dehydration due to fasting

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Gonen Baser

2016-12-01

Full Text Available Introduction: This study aimed to investigate the diurnal intraocular pressure fluctuations under dehydration conditions and the relationship between the intraocular pressure fluctuations and blood pressure. Methods: The intraocular pressures (IOP, body weights, as well as systolic and diastolic blood pressures (SBP, DBP of 36 fasting healthy volunteers were recorded at 8:00 a.m. and 5:00 p.m. in the Ramadan of 2014 and two weeks after it. The data were analyzed using paired Student’s t-test and Pearson correlation analysis. Results: As the results demonstrated, the mean diurnal IOP differences of IOP, SBP, DBP, and weight were 2.67±1.33 mmHg, 9.44±8.02 mmHg, 3.33±5.94 mmHg, and 0.90±0.46 kg during the fasting period, respectively. In addition, the mean diurnal IOP differences of IOP, SBP, DBP, and weight were -0.33±1.4 mmHg (P=0.001, 0.55±7.25mmHg (P=0.003, -3.33±5.94 mmHg (P=0.001, and 0.12±0.45 kg (P=0.001 during the control period, respectively. There was a moderate correlation between the diurnal IOP and SBP differences (r=0.517, P=0.028. Conclusion: Based on the findings of the current study, the total fluid volume might have a more dominant effect on IOP peaks than the sympathetic system activity. Furthermore, the SBP was found to correlate with the IOP.

Quantitative Assessment of the Impact of Blood Pulsation on Intraocular Pressure Measurement Results in Healthy Subjects

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Robert Koprowski

2017-01-01

Full Text Available Background. Blood pulsation affects the results obtained using various medical devices in many different ways. Method. The paper proves the effect of blood pulsation on intraocular pressure measurements. Six measurements for each of the 10 healthy subjects were performed in various phases of blood pulsation. A total of 8400 corneal deformation images were recorded. The results of intraocular pressure measurements were related to the results of heartbeat phases measured with a pulse oximeter placed on the index finger of the subject’s left hand. Results. The correlation between the heartbeat phase measured with a pulse oximeter and intraocular pressure is 0.69±0.26 (p<0.05. The phase shift calculated for the maximum correlation is equal to 60±40° (p<0.05. When the moment of measuring intraocular pressure with an air-puff tonometer is not synchronized, the changes in IOP for the analysed group of subjects can vary in the range of ±2.31 mmHg (p<0.3. Conclusions. Blood pulsation has a statistically significant effect on the results of intraocular pressure measurement. For this reason, in modern ophthalmic devices, the measurement should be synchronized with the heartbeat phases. The paper proposes an additional method for synchronizing the time of pressure measurement with the blood pulsation phase.

Circadian rhythm in idiopathic normal pressure hydrocephalus.

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Eleftheriou, Andreas; Ulander, Martin; Lundin, Fredrik

2018-01-01

The pathogenesis of idiopathic normal pressure hydrocephalus (iNPH) takes place in structures close to the cerebral ventricular system. Suprachiasmatic nucleus (SCN), situated close to the third ventricle, is involved in circadian rhythm. Diurnal disturbances are well-known in demented patients. The cognitive decline in iNPH is potentially reversible after a shunt operation. Diurnal rhythm has never been studied in iNPH. We hypothesize that there is a disturbance of circadian rhythm in iNPH-patients and the aim was to study any changes of the diurnal rhythm (mesor and circadian period) as well as any changes of the diurnal amplitude and acrophase of the activity in iNPH-patients before and after a shunt operation. Twenty consecutive iNPH-patients fulfilling the criteria of the American iNPH-guidelines, 9 males and 11 females, mean age 73 (49-81) years were included. The patients underwent a pre-operative clinical work-up including 10m walk time (w10mt) steps (w10ms), TUG-time (TUGt) and steps (TUGs) and for cognitive function an MMSE score was measured. In order to receive circadian rhythm data actigraphic recordings were performed using the SenseWear 2 (BodyMedia Inc Pittsburgh, PA, USA) actigraph. Cosinor analyses of accelerometry data were performed in "R" using non-linear regression with Levenburg- Marquardt estimation. Pre- and post-operative data regarding mesor, amplitude and circadian period were compared using Wilcoxon-Mann-Whitney test for paired data. Twenty patients were evaluated before and three month post-operatively. Motor function (w10mt, w10ms, TUGt, TUGs) was significantly improved while MMSE was not significantly changed. Actigraphic measurements (mesor, amplitude and circadian period) showed no significant changes after shunt operation. This is the first systematic study of circadian rhythm in iNPH-patients. We found no significant changes in circadian rhythm after shunt surgery. The conceptual idea of diurnal rhythm changes in hydrocephalus is

Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility

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Chintalapudi, Sumana R.; Maria, Doaa; Di Wang, Xiang; Bailey, Jessica N. Cooke; Hysi, Pirro G.; Wiggs, Janey L.; Williams, Robert W.; Jablonski, Monica M.

2017-01-01

textabstractGlaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand underlying genetic and molecular mechanisms that regulate intraocular pressure, and identifies a new candidate gene, Cacna2d1, that modulates intraocular pressure and a promising therapeutic, pregabalin, ...

Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility.

Science.gov (United States)

Chintalapudi, Sumana R; Maria, Doaa; Di Wang, Xiang; Bailey, Jessica N Cooke; Hysi, Pirro G; Wiggs, Janey L; Williams, Robert W; Jablonski, Monica M

2017-11-24

Glaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand underlying genetic and molecular mechanisms that regulate intraocular pressure, and identifies a new candidate gene, Cacna2d1, that modulates intraocular pressure and a promising therapeutic, pregabalin, which binds to CACNA2D1 protein and lowers intraocular pressure significantly. Because our study utilizes a genetically diverse population of mice with known sequence variants, we are able to determine that the intraocular pressure-lowering effect of pregabalin is dependent on the Cacna2d1 haplotype. Using human genome-wide association study (GWAS) data, evidence for association of a CACNA2D1 single-nucleotide polymorphism and primary open angle glaucoma is found. Importantly, these results demonstrate that our systems genetics approach represents an efficient method to identify genetic variation that can guide the selection of therapeutic targets.

Comparison of intraocular pressure measurement between rebound, non-contact and Goldmann applanation tonometry in treated glaucoma patients.

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Vincent, Stephen J; Vincent, Roslyn A; Shields, David; Lee, Graham A

2012-01-01

To compare the intraocular pressure readings obtained with the iCare rebound tonometer and the 7CR non-contact tonometer with those measured by Goldmann applanation tonometry in treated glaucoma patients. A prospective, cross-sectional study was conducted in a private tertiary glaucoma clinic. One hundred nine (54 males : 55 females) patients including only eyes under medical treatment for glaucoma. Measurement by Goldmann applanation tonometry, iCare rebound tonometry and 7CR non-contact tonometry. Intraocular pressure. There were strong correlations between the intraocular pressure measurements obtained with Goldmann and both the rebound and non-contact tonometers (Spearman r-values ≥ 0.79, P tonometer. For the rebound tonometer, the mean intraocular pressure was slightly higher compared with the Goldmann applanation tonometer in the right eyes (P = 0.02), and similar in the left eyes (P = 0.93); however, these differences did not reach statistical significance. The Goldmann correlated measurements from the non-contact tonometer were lower than the average Goldmann reading for both right (P 0.01) eyes. The corneal compensated measurements from the non-contact tonometer were significantly higher compared with the other tonometers (P ≤ 0.001). The iCare rebound tonometer and the 7CR non-contact tonometer measure intraocular pressure in fundamentally different ways to the Goldmann applanation tonometer. The resulting intraocular pressure values vary between the instruments and will need to be considered when comparing clinical versus home acquired measurements. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.

Comparative study of intraocular pressure (IP in Bangladeshi individuals by contact and non contact technique

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Sayed Abdul Wadud

2016-07-01

Full Text Available Background: Intraocular pressure (IOP is one of the most important parameters in the diagnosis and treatment of glaucoma. Glaucoma has been established as the second leading cause of blindness. The treatment of glaucoma focuses mainly on lowering intraocular pressure (IOP. The target IOP is often set to a level 20% to 30% of IOP reduction, and consequent large IOP reduction beyond 30% or even 40% in cases of advanced glaucoma The different methods of tonometery are: Goldman Applanation tonometery, Noncontact (air-puff tonometery, Perkins tonometery, Tonopen tonometery, Transpalpebral tonometery.Objective: To determine the frequency of accuracy of intraocular pressure (IOP measured by non-contact (air puff tonometer compared with Goldmann applanation tonometer.Methods: This was a non-interventional, cross sectional study conducted at a tertiary care centre of Dhaka, Bangladesh. consecutive subjects attending the BSMMU eye OPD were included in the study. IOP was measured by non-contact (air puff tonometer and a slit lamp mounted GAT in all the subjects. The study samples were selected by convenience sampling who presented for check-up in the Eye Department of community ophthalmology, Bangabandhu Sheikh Mujib Medical University, Dhaka. Bangladesh. Results:A total of 120 eyes in 60 patients were studied. The mean age of the patients was 41.60 year. study population consisted of 24 (40 % men and 36 (60 % women. The mean intraocular pressure was 13.52 &13.72 mmHg for GAT, and 16.64 & 17.44 mmHg for Air puff respectively. The range of measurements by GAT was from 10 to 23 mmHg and by Air puff was 12 to 28mmHg. The difference between IOP measured by two instruments were statistically significant (p=0.000.Conclusion: Airpuff tonometer is quick, a non-contact method to measure intraocular pressure and is useful for screening purposes and postoperative case but the measurements should be confirmed with Goldmann applanation tonometer for accurate labelling

Circadian blood pressure patterns and blood pressure control in patients with chronic kidney disease.

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Di Daniele, Nicola; Fegatelli, Danilo Alunni; Rovella, Valentina; Castagnola, Veronica; Gabriele, Marco; Scuteri, Angelo

2017-12-01

Hypertension is a major risk factor for chronic kidney disease (CKD), and CKD progression is associated with suboptimal blood pressure (BP) control. Here we evaluate the impact of CKD on the attainment of BP control and the circadian BP profile in older subjects. In this observational study, we studied 547 patients referred to the hypertension clinic, of whom 224 (40.9%) had CKD. Blood pressure (BP) control and circadian BP patterns were evaluated by 24-hour ambulatory BP monitoring. Circadian BP variability was measured as the within-subject SD of BP, the percentage of measurements exceeding normal values, hypotension, and dipping status. The attainment of adequate BP control was similar in subjects with or without CKD (around 31%). Logistic regression analysis indicated that CKD was not a determinant of adequate BP control (OR 1.004; 95% CI 0.989-1.019; p = 0.58). Patients with CKD presented as twice as higher prevalence of reverse dipper (night-time peak) for systolic BP and episodes of hypotension during daytime, independently of BP control. Knowledge of the circadian pattern of BP in hypertensive subjects with CKD could inform better than attainment of BP target about risky condition for CKD progression and cognitive decline and allow a more personalized antihypertensive treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of intravenous metoclopramide on intraocular pressure: A prospective, randomized, double-blind, placebo-controlled study

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Sudheera K

2008-01-01

Full Text Available Background: Prevention of rise in intraocular pressure (IOP is essential in patients undergoing surgery for perforated eye injuries. Metoclopramide, a prokinetic agent, is commonly used to hasten gastric emptying in emergency surgeries. Aim: To study the change in IOP after intravenous metoclopramide and to study the influence of metoclopramide on change in IOP after succinylcholine and tracheal intubation. Settings and Design: A randomized, double-blind, placebo-controlled study of 60 patients undergoing non-ophthalmic elective surgery. Materials and Methods: Sixty American Society of Anesthesiologists (ASA I adult patients were randomly assigned to receive normal saline (Group C or metoclopramide 10 mg (Group M 30 min before the induction of anesthesia. Thiopentone was used for induction and succinylcholine for tracheal intubation. Intraocular pressure was measured in both the eyes pre and post drug treatment and succinylcholine and tracheal intubation using Perkins applanation tonometer. Statistical Analysis: Student′s t-test and repeated measures ANOVA were used. A P value < 0.05 was considered as significant. Results: Intraocular pressure was consistently lower in Group M than in Group C after the test drug, though the difference was not statistically significant. Intraocular pressure decreased significantly after administration of thiopentone and increased significantly in Groups C and M after tracheal intubation ( P < 0.01. Intraocular pressure was comparable between the groups at all the times. Conclusions: Metoclopramide does not cause a clinically significant change in IOP nor does it influence the changes in IOP during anesthesia and tracheal intubation. Metoclopramide shows a trend towards decrease in IOP, though clinically insignificant. Therefore metoclopramide can be used to promote gastric emptying in patients with perforated eye injury.

[Circadian blood pressure variation under several pathophysiological conditions including secondary hypertension].

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Imai, Yutaka; Hosaka, Miki; Satoh, Michihiro

2014-08-01

Abnormality of circadian blood pressure (BP) variation, i.e. non-dipper, riser, nocturnal hypertension etc, is brought by several pathophysiological conditions especially by secondary hypertension. These pathophysiological conditions are classified into several categories, i.e. disturbance of autonomic nervous system, metabolic disorder, endocrine disorder, disorder of Na and water excretion (e.g. sodium sensitivity), severe target organ damage and ischemia, cardiovascular complications and drug induced hypertension. Each pathophysiological condition which brings disturbance of circadian BP variation is included in several categories, e.g. diabetes mellitus is included in metabolic disorder, autonomic imbalance, sodium sensitivity and endocrine disorder. However, it seems that unified principle of the genesis of disturbance of circadian BP variation in many pathophysiological conditions is autonomic imbalance. Thus, it is concluded that disturbance of circadian BP variation is not purposive biological behavior but the result of autonomic imbalance which looks as if compensatory reaction such as exaggerated Na-water excretion during night in patient with Na-water retention who reveals disturbed circadian BP variation.

The Advanced Glaucoma Intervention Study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration.The AGIS Investigators.

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2000-10-01

To investigate the association between control of intraocular pressure after surgical intervention for glaucoma and visual field deterioration. In the Advanced Glaucoma Intervention Study, eyes were randomly assigned to one of two sequences of glaucoma surgery, one beginning with argon laser trabeculoplasty and the other trabeculectomy. In the present article we examine the relationship between intraocular pressure and progression of visual field damage over 6 or more years of follow-up. In the first analysis, designated Predictive Analysis, we categorize 738 eyes into three groups based on intraocular pressure determinations over the first three 6-month follow-up visits. In the second analysis, designated Associative Analysis, we categorize 586 eyes into four groups based on the percent of 6-month visits over the first 6 follow-up years in which eyes presented with intraocular pressure less than 18 mm Hg. The outcome measure in both analyses is change from baseline in follow-up visual field defect score (range, 0 to 20 units). In the Predictive Analysis, eyes with early average intraocular pressure greater than 17.5 mm Hg had an estimated worsening during subsequent follow-up that was 1 unit of visual field defect score greater than eyes with average intraocular pressure less than 14 mm Hg (P =.002). This amount of worsening was greater at 7 years (1.89 units; P <.001) than at 2 years (0.64 units; P =.071). In the Associative Analysis, eyes with 100% of visits with intraocular pressure less than 18 mm Hg over 6 years had mean changes from baseline in visual field defect score close to zero during follow-up, whereas eyes with less than 50% of visits with intraocular pressure less than 18 mm Hg had an estimated worsening over follow-up of 0.63 units of visual field defect score (P =.083). This amount of worsening was greater at 7 years (1.93 units; P <.001) than at 2 years (0.25 units; P =.572). In both analyses low intraocular pressure is associated with reduced

Acute effects of consumption of energy drinks on intraocular pressure and blood pressure

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Ilechie AA

2011-04-01

Full Text Available A Alex Ilechie, Sandra TettehDepartment of Optometry, University of Cape Coast, GhanaBackground: Energy drinks contain a wide variety of ingredients including caffeine, for which there have been conflicting reports regarding its effects on intraocular pressure (IOP and blood pressure. The aim of this study was to investigate the acute effects of an energy drink (Red Bull® on the IOP and blood pressure of healthy young adults.Methods: Thirty healthy university students of either gender, aged 18–30 (mean 23.20 ± 2.81 years were randomly selected to participate in this study. The subjects were randomly divided into two groups (experimental and control and were asked to abstain from caffeine for 48 hours prior to and during the study. Baseline IOP and blood pressure were measured. The experimental group (n = 15 consumed one can of the energy drink (containing 85 mg of caffeine in 250 mL and measurements were repeated at 30, 60, and 90 minutes, while the control group drank 250 mL of water and were tested over the same time period.Results: When compared with baseline, a significant decrease (P < 0.05 in mean IOP at 60 and 90 minutes was observed in the experimental group. There was no corresponding change in systolic or diastolic blood pressure.Conclusion: Our results suggest that energy drinks (ie, Red Bull produce a significant reduction in IOP but have no effect on blood pressure. These findings may be interpreted as reflecting the effect of the combination of caffeine and taurine in the Red Bull energy drink. This effect may result from the known hypotensive effect of taurine, and warrants further study.Keywords: acute effect, intraocular pressure, blood pressure, glaucoma, caffeine, taurine

Intraocular pressure measurement in patients with previous LASIK surgery using pressure phosphene tonometer.

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Cheng, Arthur C K; Leung, Dexter Y L; Cheung, Eva Y Y; Fan, Dorothy S P; Law, Ricky W K; Lam, Dennis S C

2005-04-01

To compare intraocular pressure (IOP) assessment in post-LASIK patients using non-contact tonometry, pressure phosphene tonometry and applanation tonometry. Sixty-two consecutive LASIK patients were analysed preoperatively and postoperatively with non-contact, pressure phosphene and applanation tonometry. Comparisons among these values were assessed with paired sample Student t-test, Pearson's correlation test and Bland-Altman plotting. There was no significant difference for preoperative IOP measurement between non-contact, pressure phosphene and applanation tonometry. The mean +/-SD difference between the preoperative non-contact tonometry and postoperative pressure phosphene tonometry IOP measurements was 0.80 +/- 2.77 mmHg (P contact tonometry significantly underestimated IOP measurement by 9.96 +/- 2.25 mmHg (P < 0.001). Pressure phosphene tonometry may provide an alternative method for the assessment of IOP in post-LASIK patients.

Implantable intraocular pressure monitoring systems: Design considerations

KAUST Repository

Arsalan, Muhammad

2013-12-01

Design considerations and limitations of implantable Intraocular Pressure Monitoring (IOPM) systems are presented in this paper. Detailed comparison with the state of the art is performed to highlight the benefits and challenges of the proposed design. The system-on-chip, presented here, is battery free and harvests energy from incoming RF signals. This low-cost design, in standard CMOS process, does not require any external components or bond wires to function. This paper provides useful insights to the designers of implantable wireless sensors in terms of design choices and associated tradeoffs. © 2013 IEEE.

Implantable intraocular pressure monitoring systems: Design considerations

KAUST Repository

Arsalan, Muhammad; Ouda, Mahmoud H.; Marnat, Loic; Shamim, Atif; Salama, Khaled N.

2013-01-01

Design considerations and limitations of implantable Intraocular Pressure Monitoring (IOPM) systems are presented in this paper. Detailed comparison with the state of the art is performed to highlight the benefits and challenges of the proposed design. The system-on-chip, presented here, is battery free and harvests energy from incoming RF signals. This low-cost design, in standard CMOS process, does not require any external components or bond wires to function. This paper provides useful insights to the designers of implantable wireless sensors in terms of design choices and associated tradeoffs. © 2013 IEEE.

A randomised comparative study of the effect of Airtraq optical laryngoscope vs. Macintosh laryngoscope on intraocular pressure in non-ophthalmic surgery

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Bikramjit Das

2016-02-01

Full Text Available BACKGROUND: We compared intraocular pressure changes following laryngoscopy and intubation with conventional Macintosh blade and Airtraq optical laryngoscope. METHODS: Ninety adult patients were randomly assigned to study group or control group. Study group (n = 45 - Airtraq laryngoscope was used for laryngoscopy. Control group (n = 45 - conventional Macintosh laryngoscope was used for laryngoscopy. Preoperative baseline intraocular pressure was measured with Schiotz tonometer. Laryngoscopy was done as per group protocol. Intraocular pressure and haemodynamic parameters were recorded just before insertion of the device and subsequently three times at an interval of one minute after insertion of the device. RESULTS: Patient characteristics, baseline haemodynamic parameters and baseline intraocular pressure were comparable in the two groups. Following insertion of the endotracheal tube with Macintosh laryngoscope, there was statistically significant rise in heart rate and intraocular pressure compared to Airtraq group. There was no significant change in MAP. Eight patients in Macintosh group had tongue-lip-dental trauma during intubation, while only 2 patients received upper airway trauma in Airtraq group. CONCLUSION: We conclude that Airtraq laryngoscope in comparison to Macintosh laryngoscope results in significantly fewer rises in intraocular pressure and clinically less marked increase in haemodynamic response to laryngoscopy and intubation.

Raised intraocular pressure and recurrence of retinal detachment as complications of external retinal detachment surgery

International Nuclear Information System (INIS)

Jawwad, M.; Khan, B.; Shah, M.A.; Qayyum, I.; Aftab, M.; Qayyum, I.

2015-01-01

Patients with Rhegmatogenous retinal detachment may develop raised intraocular pressure and recurrence of retinal detachment when they undergo external retinal detachment surgery. The present study was conducted to determine the postoperative rise in intraocular pressure (IOP) and recurrence of retinal detachment. Methods: The present descriptive study was conducted at Eye department of Lady Reading Hospital, Peshawar on 25 patients of both genders from August 2012 to July 2014. Results: Of the 25 patients, 18 (72%) developed raised IOP in the immediate postoperative period; this figure decreased to 12 (48%) at one week. Following medical or surgical intervention in these 12 cases, there was only 1 (4%) case with mildly raised IOP at two weeks postoperative. Five (20%) cases developed recurrent retinal detachment which later resolved with treatment. There were no significant differences by age or gender. Conclusion: External Retinal Detachment Surgery raised intraocular pressure postoperatively and caused recurrence of retinal detachment. These complications were treated medically and surgically with resolution within two weeks. (author)

Intermediate-term and long-term outcome of piggyback drainage: connecting glaucoma drainage device to a device in-situ for improved intraocular pressure control.

Science.gov (United States)

Dervan, Edward; Lee, Edward; Giubilato, Antonio; Khanam, Tina; Maghsoudlou, Panayiotis; Morgan, William H

2017-11-01

This study provides results of a treatment option for patients with failed primary glaucoma drainage device. The study aimed to describe and evaluate the long-term intraocular pressure control and complications of a new technique joining a second glaucoma drainage device directly to an existing glaucoma drainage device termed 'piggyback drainage'. This is a retrospective, interventional cohort study. Eighteen eyes of 17 patients who underwent piggyback drainage between 2004 and 2013 inclusive have been studied. All patients had prior glaucoma drainage device with uncontrolled intraocular pressure. The piggyback technique involved suturing a Baerveldt (250 or 350 mm) or Molteno3 glaucoma drainage device to an unused scleral quadrant and connecting the silicone tube to the primary plate bleb. Failure of intraocular pressure control defined as an intraocular pressure greater than 21 mmHg on maximal therapy on two separate occasions or further intervention to control intraocular pressure. The intraocular pressure was controlled in seven eyes (39%) at last follow-up with a mean follow-up time of 74.2 months. The mean preoperative intraocular pressure was 27.1 mmHg (95% confidence interval 23.8-30.3) compared with 18.4 mmHg (95% confidence interval 13.9-22.8) at last follow-up. The mean time to failure was 57.1 months (95% confidence interval 32.2-82), and the mean time to further surgery was 72.3 months (95% confidence interval 49.9-94.7). Lower preoperative intraocular pressure was associated with longer duration of intraocular pressure control (P = 0.048). If the intraocular pressure was controlled over 2 years, it continued to be controlled over the long term. Two eyes (11%) experienced corneal decompensation. Piggyback drainage represents a viable surgical alternative for the treatment of patients with severe glaucoma with failing primary glaucoma drainage device, particularly in those at high risk of corneal decompensation. © 2017 Royal Australian and New Zealand

Poor correlation between intracranial pressure and intraocular pressure by hand-held tonometry

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Golan S

2013-06-01

Full Text Available Shani Golan,1 Shimon Kurtz,1 Daphna Mezad-Koursh,1 Michael Waisbourd,1 Anat Kesler,1 Pinchas Halpern2 1Departments of Ophthalmology, Tel Aviv Sourasky Medical Center, affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; 2Emergency Medicine, Tel Aviv Sourasky Medical Center, affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Purpose: The aim of this study is to provide data on the controversial issue of whether handheld measurements of intraocular pressure (IOP are capable of accurately predicting elevated intracranial pressure (ICP in patients undergoing lumbar puncture (LP. Methods: All patients over the age of 18 years who underwent an LP in the emergency or neurological departments at the Tel Aviv Medical center for any reason between October 2007 and July 2010 were eligible to participate in this prospective observational pilot study. IOP was measured with the Tono-Pen XL while patients were in the supine position before undergoing LP. ICP was measured in the lateral recumbent position. ICP and bilateral IOP were measured, and the mean and maximum values of IOP were calculated. The association between ICP and each one of the four IOP measures was evaluated by the Pearson correlation coefficient. Results: Twenty-four patients (mean age 37.8 ± 15.8 years, ten males and 14 females were enrolled. The reasons for their requiring an LP were headache (19/24 patients, evaluation for hemiparesis (2/24, cognitive deterioration (1/24, and seizures (2/24. Nine had elevated mean opening pressure (>20 cm H2O, six had an elevated mean IOP (>20 mmHg, and four of these six also had an elevated opening pressure. There was no significant correlation between the ICP measurements and any of the IOP measurements. Conclusion: Handheld ocular tonometry has poor sensitivity and specificity for the prediction of increased ICP and is not an effective tool for screening for ICP in the ED or in the

Pigment dispersion and chronic intraocular pressure elevation after sulcus placement of 3-piece acrylic intraocular lens.

Science.gov (United States)

Almond, M Camille; Wu, Michael C; Chen, Philip P

2009-12-01

A 55-year-old man had phacoemulsification and implantation of a 3-piece acrylic intraocular lens (IOL) (AcrySof MA60AC) in the right eye. One month postoperatively, the intraocular pressure (IOP) was 48 mm Hg and peripheral transillumination defects were noted in the iris circumferentially, with the IOL optic edge visible as a silhouette. Gonioscopy showed dense pigmentation of the trabecular meshwork in the right eye, but in the left eye, only mild trabecular meshwork pigment was seen, along with a concave peripheral iris insertion. At 21 months, the right eye required 3 medications for IOP control. While pigment dispersion has been widely reported after placement of 1-piece acrylic IOLs in the ciliary sulcus, we conclude that in susceptible individuals with a concave peripheral iris insertion, pigment dispersion can occur with sulcus placement of a 3-piece acrylic model despite its thinner optic and angulated haptics.

Common Genetic Determinants of Intraocular Pressure and Primary Open-Angle Glaucoma

NARCIS (Netherlands)

van Koolwijk, Leonieke M. E.; Ramdas, Wishal D.; Ikram, M. Kamran; Jansonius, Nomdo M.; Pasutto, Francesca; Hysi, Pirro G.; Macgregor, Stuart; Janssen, Sarah F.; Hewitt, Alex W.; Viswanathan, Ananth C.; ten Brink, Jacoline B.; Hosseini, S. Mohsen; Amin, Najaf; Despriet, Dominiek D. G.; Willemse-Assink, Jacqueline J. M.; Kramer, Rogier; Rivadeneira, Fernando; Struchalin, Maksim; Aulchenko, Yurii S.; Weisschuh, Nicole; Zenkel, Matthias; Mardin, Christian Y.; Gramer, Eugen; Welge-Luessen, Ulrich; Montgomery, Grant W.; Carbonaro, Francis; Young, Terri L.; Bellenguez, Celine; McGuffin, Peter; Foster, Paul J.; Topouzis, Fotis; Mitchell, Paul; Wang, Jie Jin; Wong, Tien Y.; Czudowska, Monika A.; Hofman, Albert; Uitterlinden, Andre G.; Wolfs, Roger C. W.; de Jong, Paulus T. V. M.; Oostra, Ben A.; Paterson, Andrew D.; Mackey, David A.; Bergen, Arthur A. B.; Reis, Andre; Hammond, Christopher J.; Vingerling, Johannes R.; Lemij, Hans G.; Klaver, Caroline C. W.; van Duijn, Cornelia M.

2012-01-01

Intraocular pressure (IOP) is a highly heritable risk factor for primary open-angle glaucoma and is the only target for current glaucoma therapy. The genetic factors which determine IOP are largely unknown. We performed a genome-wide association study for IOP in 11,972 participants from 4

The Effect of Altitude on Intraocular Pressure in Vitrectomized Eyes with Sulfur Hexafluoride Tamponade by the Friedenwald Method: Rabbit Animal Model

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Jans Fromow-Guerra

2016-01-01

Full Text Available The aim of this study is to assess the change in intraocular pressure after a road trip, in eyes with different levels of filling with gas tamponade. Five rabbit eyes were subject to pars plana vitrectomy and gas tamponade (filling percentage: 25%, 50%, and 100% of nonexpansile SF6, 100% saline solution, and 100% room air. A sixth eye was injected with 0.35 cc of undiluted SF6 without vitrectomy. Guided by global positioning system, they were driven to the highest point of the highway connecting Mexico City with Puebla city and back, stopping every 300 m to assess intraocular pressure. The rabbit’s scleral rigidity and estimation for human eyes were done by using the Friedenwald nomogram. Maximum altitude was 3209 m (Δ949 m. There were significant differences in intraocular pressure on the rabbit eyes filled with SF6 at 100%, 50%, 25%, and 100% room air. Per every 100 m of altitude rise, the intraocular pressure increased by 1.53, 1.0046, 0.971, and 0.97 mmHg, respectively. Using the human Friedenwald rigidity coefficient, the human eye estimate for intraocular pressure change was 2.1, 1.8, 1.4, and 1.1 mmHg per every 100 m of attitude rise. Altitude changes have a significant impact on intraocular pressure. The final effect depends on the percentage of vitreous cavity fill and scleral rigidity.

Circadian Misalignment Increases C-Reactive Protein and Blood Pressure in Chronic Shift Workers.

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Morris, Christopher J; Purvis, Taylor E; Mistretta, Joseph; Hu, Kun; Scheer, Frank A J L

2017-04-01

Shift work is a risk factor for inflammation, hypertension, and cardiovascular disease. This increased risk cannot be fully explained by classical risk factors. Shift workers' behavioral and environmental cycles are typically misaligned relative to their endogenous circadian system. However, there is little information on the impact of acute circadian misalignment on cardiovascular disease risk in shift workers, independent of differences in work stress, food quality, and other factors that are likely to differ between night and day shifts. Thus, our objectives were to determine the independent effect of circadian misalignment on 24-h high-sensitivity C-reactive protein (hs-CRP; a marker of systemic inflammation) and blood pressure levels-cardiovascular disease risk factors-in chronic shift workers. Chronic shift workers undertook two 3-day laboratory protocols that simulated night work, comprising 12-hour inverted behavioral and environmental cycles (circadian misalignment) or simulated day work (circadian alignment), using a randomized, crossover design. Circadian misalignment increased 24-h hs-CRP by 11% ( p shift workers. This may help explain the increased inflammation, hypertension, and cardiovascular disease risk in shift workers.

Intraocular pressure measurements after conductive keratoplasty.

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Kymionis, George D; Naoumidi, Tatiana L; Aslanides, Ioannis M; Kumar, Vinod; Astyrakakis, Nikolaos I; Tsilimbaris, Miltiadis; Pallikaris, Ioannis G

2005-01-01

To determine the possible impact of conductive keratoplasty (CK) on intraocular pressure (IOP) measurements. A prospective, single-center, noncomparative interventional case series was performed. Baseline and postoperative IOPs were measured by Goldmann applanation tonometry in 32 eyes of 18 patients who underwent CK for hyperopia correction. Mean follow-up was 11.9 months (range: 8 to 18 months). After CK, a statistically significant decrease in the measured IOP was observed (before CK: 14.22+/-1.64 vs after CK: 12.66+/-2.21, P<.001). The change in IOP readings postoperatively was not correlated with age, sex, keratometric readings, or attempted correction. Despite the limitations due to the small number of patients enrolled in this study, the applanation tonometer appears to underestimate the true IOP after CK.

Assessment of intraocular pressure in chinchillas of different age groups using rebound tonometry

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Flor Diana Yokoay Claros Chacaltana

2016-01-01

Full Text Available ABSTRACT: The aim of this research was to measure the intraocular pressure (IOP of normal chinchilla eyes using the rebound tonometer. A further aim was to assess whether there were differences in the values of intraocular pressure in relation to animals age, gender and time of day. Thirty-six chinchillas were divided into three groups of 12 chinchillas each, by age: Group I (2-6-month-old, Group II (20 and 34 months and Group III (37 and 135 months. Ophthalmic examination was performed previously by Schirmer tear test, slit lamp biomicroscopy, indirect ophthalmoscopy and fluorescein test in all chinchillas. Three measurements of intraocular pressure were assessed on the same day (7, 12 and 19h. Tonometry was performed on both eyes using the rebound tonometer after calibration in "p" mode. Statistical analysis was performed with SigmaPlot for Windows. The mean IOP for groups I, II and III were 2.47±0.581mmHg, 2.47±0.581mmHg and 2.51±0.531mmHg, respectively. No significant differences were reported between age and IOP and no significant differences were reported between the time of day and IOP. The IOP in chinchillas did not differ significantly between genders or ages of the animals, and did not change with time of day.

The Comparison of the Influence of Thiopental and Propofol on Intraocular Pressure during Induction of Anesthesia in Intubated Patients under Cataracct Surgery

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Reza Sahraei

2016-07-01

Full Text Available The prevention of the increase of intraocular pressure and the further decrease of it during eye surgery has an impressive effect on the success of surgery. Some of the phases of the induction of anesthesia like laryngoscopy and tracheal intubation result in the increase of intraocular pressure and its consequences are dangerous for penetrating injuries of eyeball. The goal of this research is the comparison of the changes of intraocular pressure during the induction of anesthesia in completely same conditions by using thiopental and propofol and also the careful investigation of their influences on intraocular pressure in order to select the medicine that effectively decrease the intraocular pressure and prevent the increase of it after laryngoscopy and tracheal intubation. In this research, 88 patients were selected and they were randomly divided into 2 groups. In the beginning of the patients' anesthesia, both groups were preoxygenated and they simultaneously receive initial dose of atracurium (0/5 mg/kg and then initial dose of fentanyl (1-2 µg/Kg. After prescription of fentanyl, the induction of anesthesia in the first group was done withthiopental (4 mg/kg and in the second group with propofol (2/5 mg/kg and after that, atracurium intubation (0/7 mg/kg was prescribed. Intraocular pressure is measured in two phases before induction of anesthesia (with tetracaine eyedrop and 3 minutes after intubation (with schiotz tonometer and 3±0/75 degree of accuracy and by a person who is not aware of the kind of anesthesia. The patients are replicated in 2 experimental and control groups in terms of age and gender. The results of independent t-test show that there is no significant difference between 2 groups of thiopental and propofol in terms of systolic and diastolic blood pressure, heart beat and eye pressure before the induction of anesthesia (p-value>0,05. The results of independent t-test show that there is a significant difference between2

Effects of autogenic training and antihypertensive agents on circadian and circaseptan variation of blood pressure.

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Watanabe, Yoshihiko; Cornélissen, Germaine; Watanabe, Misako; Watanabe, Fumihiko; Otsuka, Kuniaki; Ohkawa, Shi-ichiro; Kikuchi, Takenori; Halberg, Franz

2003-10-01

Even when the daily blood pressure mean is acceptable, too large a circadian amplitude of blood pressure largely increases cardiovascular disease risk. Autogenic training (N = 11), a non-pharmacologic intervention capable of lowering an excessive blood pressure variability, may be well-suited for MESOR-normotensive patients diagnosed with circadian-hyper-amplitude-tension (CHAT). Not all anti-hypertensive drugs affect blood pressure variability. Accordingly, long-acting carteolol (N = 11) and/or atenolol (N = 8) may be preferred to captopril retard (N = 13), nilvadipine (N = 8), or amlodipine (N = 7) for midline-estimating statistic of rhythm (MESOR)-hypertensive patients with CHAT. Prospective outcome studies are needed to assess whether the relative merits of these treatments are in keeping with their effects on blood pressure and blood pressure variability.

The effect of lens aging and cataract surgery on circadian rhythm.

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Yan, Shen-Shen; Wang, Wei

2016-01-01

Many organisms have evolved an approximately 24-hour circadian rhythm that allows them to achieve internal physiological homeostasis with external environment. Suprachiasmatic nucleus (SCN) is the central pacemaker of circadian rhythm, and its activity is entrained to the external light-dark cycle. The SCN controls circadian rhythm through regulating the synthesis of melatonin by pineal gland via a multisynaptic pathway. Light, especially short-wavelength blue light, is the most potent environmental time cue in circadian photoentrainment. Recently, the discovery of a novel type of retinal photoreceptors, intrinsically photosensitive retinal ganglion cells, sheds light on the mechanism of circadian photoentrainment and raises concerns about the effect of ocular diseases on circadian system. With age, light transmittance is significantly decreased due to the aging of crystalline lens, thus possibly resulting in progressive loss of circadian photoreception. In the current review, we summarize the circadian physiology, highlight the important role of light in circadian rhythm regulation, discuss about the correlation between age-related cataract and sleep disorders, and compare the effect of blue light- filtering intraocular lenses (IOLs) and ultraviolet only filtering IOLs on circadian rhythm.

Could White Coat Ocular Hypertension Affect to the Accuracy of the Diagnosis of Glaucoma? Relationships Between Anxiety and Intraocular Pressure in a Simulated Clinical Setting.

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Méndez-Ulrich, Jorge Luis; Sanz, Antoni; Feliu-Soler, Albert; Álvarez, María; Borràs, Xavier

2018-03-01

Sixty-one healthy subjects participated in a laboratory study carried out in a simulated clinical setting. Anticipatory anxiety-state was assessed at the arrival and immediately after, with no brief phase of adaptation, measurements of intraocular pressure, heart rate, systolic and diastolic blood pressure were collected. At the end of the procedure, anxiety-trait was also assessed. Results suggest that high levels of both anxiety-state and anxiety-trait significantly predicted a clinically relevant increase of intraocular pressure. Anxiety-state mediated the relationship between anxiety-trait and intraocular pressure, which also was found to be related with heart rate but not related to both systolic and diastolic blood pressure. These results suggest a common mechanism of regulation underlying anxiogenic variability found on both intraocular pressure and heart rate. A reduction in parasympathetic activity appears as a possible mechanism underlying to this phenomenon. This anxiety-enhanced intraocular pressure could be considered a phenomenon analogous to white coat hypertension found in the measurement of blood pressure; therefore, it probably should be taken into account in the clinical context to prevent errors in the diagnosis of glaucoma. Further research on cognitive and emotional regulation of intraocular pressure is needed to best characterize this hypothetical phenomenon.

LONG-TERM INTRAOCULAR PRESSURE AFTER UNCOMPLICATED PARS PLANA VITRECTOMY FOR IDIOPATHIC EPIRETINAL MEMBRANE.

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Tognetto, Daniele; Pastore, Marco R; Cirigliano, Gabriella; DʼAloisio, Rossella; Borelli, Massimo; De Giacinto, Chiara

2017-11-16

To investigate long-term intraocular pressure trends after uncomplicated pars plana vitrectomy for idiopathic epiretinal membrane. Three hundred and sixty-eight eyes of 368 consecutive patients were enrolled. Changes in intraocular pressure 1, 3, 6, and 12 months after surgery and during the final follow-up visit were evaluated in vitrectomized eyes and nonvitrectomized fellow eyes. The median follow-up period was 36 months (range 12-92 months). Longitudinal data analysis evidenced a 2.5-mmHg (2.2 mmHg; 2.7 mmHg, 95% confidence interval) statistically significant difference in intraocular pressure 30 days after surgery between treated and fellow untreated eyes, gradually recovering to a not significant 0.2-mmHg (-0.1 mmHg; 0.4 mmHg, 95% confidence interval) difference within 26 months. The incidence of late-onset ocular hypertension was 5.7% (21 over 347, 2%; 12%, 95% confidence interval) without difference between the treated eyes and the group control. No significant difference in the incidence of late-onset ocular hypertension and sex, lens status, or gauge of vitrectomy instruments was detected. Only patient's age was significantly higher (mean difference 4.2 years; 0.1-8.0 years, Monte Carlo, 95% confidence interval) in those who developed late-onset ocular hypertension in the vitrectomized eye. Uncomplicated pars plana vitrectomy for idiopathic epiretinal membrane seems not to increase the risk of late-onset ocular hypertension or open-angle glaucoma development.

The Role of Beta-Adrenergic Receptors in the Regulation of Circadian Intraocular Pressure Rhythm in Mice.

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Tsuchiya, Shunsuke; Higashide, Tomomi; Toida, Kazunori; Sugiyama, Kazuhisa

2017-07-01

To investigate whether the elimination of β1- and β2-adrenergic receptors alters the diurnal intraocular pressure (IOP) rhythm in mice. β1-/β2-adrenergic receptor double-knockout and C57BL/6J mice were anesthetized intraperitoneally, with their IOPs measured via microneedle method. After entrainment to a 12-h light-dark (LD) cycle (light phase 6:00-18:00), IOPs were measured every 3 h from 9:00 to 24:00 (group 1, β1-/β2-adrenergic receptor double-knockout mice, n = 11; C57BL/6J, n = 15). The IOP measurements at 15:00 and 24:00 under a 12-h LD cycle and in the constant darkness (1 day and 8 days after exposure to darkness, respectively) were performed in another group of β1-/β2-adrenergic receptor double-knockout mice (group 2, n = 12). IOP variance throughout the day and mean IOP differences among time points were evaluated using a linear mixed model. β1-/β2-adrenergic receptor double-knockout and C57BL/6J mice showed biphasic IOP curves, low during the light phase and high during the dark phase; the fluctuation was significant (P adrenergic receptor double-knockout mice group. IOP curves of β1-/β2-adrenergic receptor double-knockout and C57BL/6J were nearly parallel, and the IOPs of β1-/β2-adrenergic receptor double-knockout mice were significantly higher than those of C57BL/6J mice (P adrenergic receptors did not disturb the biphasic diurnal IOP rhythm in mice.

Associations with intraocular pressure across Europe: The European Eye Epidemiology (E-3) Consortium

NARCIS (Netherlands)

Khawaja, Anthony P.; Springelkamp, Henriët; Creuzot-Garcher, Catherine; Delcourt, Cécile; Hofman, Albert; Höhn, René; Iglesias, Adriana I.; Wolfs, Roger C. W.; Korobelnik, Jean-François; Silva, Rufino; Topouzis, Fotis; Williams, Katie M.; Bron, Alain M.; Buitendijk, Gabriëlle H. S.; Cachulo, Maria da Luz; Cougnard-Grégoire, Audrey; Dartigues, Jean-François; Hammond, Christopher J.; Pfeiffer, Norbert; Salonikiou, Angeliki; van Duijn, Cornelia M.; Vingerling, Johannes R.; Luben, Robert N.; Mirshahi, Alireza; Lamparter, Julia; Klaver, Caroline C. W.; Jansonius, Nomdo M.; Foster, Paul J.; Acar, Niyazi; Anastosopoulos, Eleftherios; Azuara-Blanco, Augusto; Bergen, Arthur; Bertelsen, Geir; Binquet, Christine; Bird, Alan; Brétillon, Lionel; Bron, Alain; Buitendijk, Gabrielle; Cachulo, Maria Luz; Chakravarthy, Usha; Chan, Michelle; Chang, Petrus; Colijn, Annemarie; Cumberland, Philippa; Cunha-Vaz, José; Daien, Vincent; Deak, Gabor; Delyfer, Marie-Noëlle; Hollander, Anneke den; Dietzel, Martha; Erke, Maja Gran; Fauser, Sascha; Finger, Robert; Fletcher, Astrid; Foster, Paul; Founti, Panayiota; Göbel, Arno; Gorgels, Theo; Grauslund, Jakob; Grus, Franz; Hammond, Christopher; Helmer, Catherine; Hense, Hans-Werner; Hermann, Manuel; Hoehn, René; Hogg, Ruth; Holz, Frank; Hoyng, Carel; Jansonius, Nomdo; Janssen, Sarah; Khawaja, Anthony; Klaver, Caroline; Le Goff, Mélanie; Leal, Sergio; Lechanteur, Yara; Lehtimäki, Terho; Lotery, Andrew; Leung, Irene; Mauschitz, Matthias; Merle, Bénédicte; Meyer Zu Westrup, Verena; Midena, Edoardo; Miotto, Stefania; Mohan-Saïd, Sadek; Muldrew, Alyson; Mueller, Michael; Nunes, Sandrina; Oexle, Konrad; Peto, Tunde; Piermarocchi, Stefano; Prokofyeva, Elena; Rahi, Jugnoo; Raitakari, Olli; Ribeiro, Luisa; Rougier, Marie-Bénédicte; Sahel, José; Salonikiou, Aggeliki; Sanchez, Clarisa; Schmitz-Valckenberg, Steffen; Schweitzer, Cédric; Segato, Tatiana; Shehata, Jasmin; Silvestri, Giuliana; Simader, Christian; Souied, Eric; Springelkamp, Henriet; Tapp, Robyn; Verhoeven, Virginie; Von Hanno, Therese; Vujosevic, Stela; Williams, Katie; Wolfram, Christian; Yip, Jennifer; Zerbib, Jennyfer; Zwiener, Isabella

2016-01-01

Raised intraocular pressure (IOP) is the most important risk factor for developing glaucoma, the second commonest cause of blindness globally. Understanding associations with IOP and variations in IOP between countries may teach us about mechanisms underlying glaucoma. We examined cross-sectional

Comparison of current tonometry techniques in measurement of intraocular pressure.

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Kouchaki, Behrooz; Hashemi, Hassan; Yekta, Abbasali; Khabazkhoob, Mehdi

2017-06-01

To compare four tonometry techniques: Goldmann applanation tonometer (GAT), Dynamic contour tonometer (DCT), Non-contact tonometer (NCT), and Ocular Response Analyzer (ORA) in the measurement of intraocular pressure (IOP) and the impact of some corneal biomechanical factors on their performance. In this cross-sectional study, volunteers with normal ophthalmic examination and no history of eye surgery (except for uncomplicated cataract surgery) or trauma were selected. Twenty-five subjects were male, and 21 were female. The mean age was 48 ± 19.2 years. Anterior segment parameters were measured with Scheimpflug imaging. IOP was measured with GAT, DCT, NCT, and ORA in random order. A 95% limit of agreement of IOPs was analyzed. The impact of different parameters on the measured IOP with each device was evaluated by regression analysis. The average IOP measured with GAT, DCT, NCT, and ORA was 16.4 ± 3.5, 18.1 ± 3.4, 16.2 ± 3.9, and 17.3 ± 3.4 mmHg, respectively. The difference of IOP measured with NCT and GAT was not significant ( P  = 0.382). Intraocular pressure was significantly different between GAT with DCT and IOP CC ( P  tonometers.

Inflammatory and intraocular pressure outcomes after trabeculectomy in active uveitic glaucoma in Chinese

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Doris W.F. Yick

2015-06-01

Full Text Available AIM: To analyze the outcomes in uveitic activity and intraocular pressure(IOPcontrol after trabeculectomy for uveitis with uncontrolled IOP. METHODS: The medical records of consecutive uveitic glaucoma patients undergoing trabeculectomy between October 2006 to March 2011 were retrospectively reviewed. Uveitic activity, frequency of recurrence, steroid dependence, and intraocular pressure control were compared with paired t-test before and after trabeculectomy. RESULTS: In 29 eyes from 29 patients, 90% of eyes were on topical steroids at the time of trabeculectomy. The mean age was 58.3±14.0 years old with a pre-operative IOP of 35.7±8.9mmHg. The mean follow up time was 35.2±18.7mo. There was a reduction of anterior chamber activity grading of 0.4±0.6(PPCONCLUSION: Uveitic activity and IOP control improved after trabeculectomy with a lower success rate to primary glaucomas. Trabeculectomy may be considered as a possible early intervention of active uveitis with high IOP for pressure and uveitic activity control.

Blood pressure modifies retinal susceptibility to intraocular pressure elevation.

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Zheng He

Full Text Available Primary open angle glaucoma affects more than 67 million people. Elevated intraocular pressure (IOP is a risk factor for glaucoma and may reduce nutrient availability by decreasing ocular perfusion pressure (OPP. An interaction between arterial blood pressure and IOP determines OPP; but the exact contribution that these factors have for retinal function is not fully understood. Here we sought to determine how acute modifications of arterial pressure will affect the susceptibility of neuronal function and blood flow to IOP challenge. Anaesthetized (ketamine:xylazine Long-Evan rats with low (∼60 mmHg, sodium nitroprusside infusion, moderate (∼100 mmHg, saline, or high levels (∼160 mmHg, angiotensin II of mean arterial pressure (MAP, n = 5-10 per group were subjected to IOP challenge (10-120 mmHg, 5 mmHg steps every 3 minutes. Electroretinograms were measured at each IOP step to assess bipolar cell (b-wave and inner retinal function (scotopic threshold response or STR. Ocular blood flow was measured using laser-Doppler flowmetry in groups with similar MAP level and the same IOP challenge protocol. Both b-wave and STR amplitudes decreased with IOP elevation. Retinal function was less susceptible to IOP challenge when MAP was high, whereas the converse was true for low MAP. Consistent with the effects on retinal function, higher IOP was needed to attenuated ocular blood flow in animals with higher MAP. The susceptibility of retinal function to IOP challenge can be ameliorated by acute high BP, and exacerbated by low BP. This is partially mediated by modifications in ocular blood flow.

Effect of Topical Calcium Channel Blockers on Intraocular Pressure in Steroid-induced Glaucoma.

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Ganekal, Sunil; Dorairaj, Syril; Jhanji, Vishal; Kudlu, Krishnaprasad

2014-01-01

To evaluate the effect of 0.125% verapamil and 0.5% diltiazem eye drops on intraocular pressure (IOP) in steroid-induced glaucoma in rabbit eyes. A total of 18 rabbits with steroid-induced glaucoma were divided into three groups (A, B and C; n = 6 each). Right eyes in groups A, B and C received 0.5% diltiazem, 0.125% verapamil and 0.5% timolol eye drops twice daily for 12 days, respectively; whereas, left eyes received distilled water. IOP was measured with Tono-pen XL at baseline, day 4, day 8, and day 12 of treatment. Both 0.5% diltiazem and 0.125% verapamil eye drops significantly reduced IOP compared to control eyes (p cite this article: Ganekal S, Dorairaj S, Jhanji V, Kudlu K. Effect of Topical Calcium Channel Blockers on Intraocular Pressure in Steroid-induced Glaucoma. J Current Glau Prac 2014;8(1):15-19.

Measurement of intraocular pressure with pressure phosphene tonometry in children.

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Fan, Dorothy S P; Chiu, Thomas Y H; Congdon, Nathan; Chan, Jeffrey C W; Cheung, Eva Y Y; Lam, Dennis S C

2011-01-01

To study the accuracy and acceptability of intraocular pressure (IOP) measurement by the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer in children. Fifty children (5 to 14 years old) participated in this prospective comparative study. IOP was measured with the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer by three different examiners who were masked to the results. The children were also asked to grade the degree of discomfort from 0 to 5 (0 = no discomfort; 5 = most discomfort). The mean IOPs measured by the Goldmann tonometer, pressure phosphene tonometer, and non-contact tonometer were 15.9 mm Hg (standard deviation [SD]: = 5.5 mm Hg; range: 10 to 36 mm Hg), 16.0 mm Hg (SD: 2.9 mm Hg; range: 12 to 25 mm Hg), and 15.7 mm Hg (SD = 5.1 mm Hg; range: 8 to 32 mm Hg), respectively (P = .722). The mean difference between pressure phosphene tonometer and Goldmann tonometer readings was 2.9 mm Hg and that between non-contact tonometer and Goldmann tonometer readings was 2.1 mm Hg. The 95% confidence interval of the mean difference between pressure phosphene tonometer and Goldmann tonometer readings was -1.07 and 1.19, and that between non-contact tonometer and Goldmann tonometer readings was -1.07 and 0.53. The mean discomfort ratings for the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer were 0.6, 2.0, and 2.3, respectively (P tonometer was less accurate than the non-contact tonometer compared with Goldmann tonometer, it gave a reasonably close estimate and had a high specificity of raised IOP. In addition, measurement by the pressure phosphene tonometer is most acceptable to children. The pressure phosphene tonometer can be considered as an alternative method of IOP measurement in children. Copyright 2011, SLACK Incorporated.

Early aggressive intraocular pressure lowering, target intraocular pressure, and a novel concept for glaucoma care.

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Singh, Kuldev; Shrivastava, Anurag

2008-11-01

Early diagnosis of glaucomatous optic nerve damage offers the potential for early treatment which may prevent vision loss from this neurodegenerative disease. Even in patients who do not begin early treatment, early diagnosis allows for better monitoring of disease at a stage where the stakes are lower relative to later stages of the disease. For these reasons, early diagnosis of glaucomatous optic nerve disease is desirable and opens the door for appropriately aggressive therapy. The target intraocular pressure (IOP) concept is widely employed by glaucoma practitioners. Although there have been no randomized clinical trials or other high-quality studies showing the benefits of setting a target IOP versus not using this approach, there is ample evidence that lowering IOP slows glaucoma progression and, in general, lower is better, regardless of disease stage and baseline IOP level. We propose an alternative approach to managing glaucoma without the use of the target IOP concept and suggest that this market IOP concept should be compared with the target IOP approach in an appropriately powered comparative clinical trial.

Study on the pathogenesis of transient intraocular pressure after laser iridectomy with Krypton laser combined with Q-switched Nd:YAG laser

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Zhi-Juan Pei

2017-12-01

Full Text Available AIM: To study the pathogenesis of transient intraocular pressure(IOPafter laser iridectomy with Krypton laser combined with Q-switched Nd:YAG laser. METHODS: Totally 42 healthy rabbits(84 eyesprovided by the Animal Experimental Center of our hospital were selected, including 18 female rabbits, 24 male rabbits, average weight 2.24±0.31kg, and they were randomly divided into 6 groups, 7 rats in each group(14 eyes. We observed the change of intraocular pressure after laser iridectomy surgery at 20min, 2, 6, 18, 24h and the nitric oxide(NO, malondialdehyde(MDA, superoxide dismutase(SOD, 6-keto-prostaglandin(6-keto-PGF1αand nitric oxide synthase(NOScontent in aqueous. RESULTS: There was no significant difference in intraocular pressure, NO, NOS, SOD, MAD and 6-keto- PGF1α before operation(P>0.05. The intraocular pressure increased after operation, and the difference was statistically significant(PP>0.05. The levels of NO, NOS and SOD in the aqueous humor of the two groups decreased 20min, 2 and 6h after the operation(PP>0.05. The levels of MDA and 6-keto-prostaglandin in the aqueous humor increased after the operation, and the difference was statistically significant at 20min, 2 and 6h after operation(PP>0.05.CONCLUSION: The increase of transient intraocular pressure after laser iridectomy may relate to the increase of malondialdehyde, 6-keto-prostaglandin content and the decrease of superoxide dismutase and nitric oxide in the aqueous humor after operation.

Combined ab interno trabeculotomy and lens extraction: a novel management option for combined uveitic and chronic narrow angle raised intraocular pressure.

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Lin, Siying; Gupta, Bhaskar; Rossiter, Jonathan

2016-02-01

Minimally invasive glaucoma surgery is a developing area that has the potential to replace traditional glaucoma surgery, with its known risk profile, but at present there are no randomised controlled data to validate its use. We report on a case where sequential bilateral combined ab interno trabeculotomy and lens extraction surgery was performed on a 45-year-old woman with combined uveitic and chronic narrow angle raised intraocular pressure. Maximal medical management alone could not control the intraocular pressure. At 12-month follow-up, the patient had achieved stable intraocular pressure in both eyes on a combination of topical ocular antiglaucomatous and steroid therapies. This case demonstrates the effectiveness of trabecular meshwork ablation via ab interno trabeculotomy in a case of complex mixed mechanism glaucoma. 2016 BMJ Publishing Group Ltd.

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

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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.

Genome-wide association study of intraocular pressure identifies the GLCCI1/ICA1 region as a glaucoma susceptibility locus

OpenAIRE

Strange, Amy; Bellenguez, Céline; Sim, Xueling; Luben, Robert; Hysi, Pirro G.; Ramdas, Wishal D.; van Koolwijk, Leonieke M.E.; Freeman, Colin; Pirinen, Matti; Su, Zhan; Band, Gavin; Pearson, Richard; Vukcevic, Damjan; Langford, Cordelia; Deloukas, Panos

2013-01-01

To discover quantitative trait loci for intraocular pressure, a major risk factor for glaucoma and the only modifiable one, we performed a genome-wide association study on a discovery cohort of 2175 individuals from Sydney, Australia. We found a novel association between intraocular pressure and a common variant at 7p21 near to GLCCI1 and ICA1. The findings in this region were confirmed through two UK replication cohorts totalling 4866 individuals (rs59072263, P(combined) = 1.10 × 10(-8)). A ...

Role of cataract surgery in lowering intraocular pressure

International Nuclear Information System (INIS)

Ahmad, S.; Sabih, A.

2015-01-01

To study the effects of cataract surgery in lowering of intraocular pressure (IOP). Study Design: Retrospective study. Place and Duration of Study: The Department of Ophthalmology, Combined Military Hospital, Rawalpindi from January 2011 to December 2013. Patients and Methods: The study included a total of 250 patients; of which 100 cases had simple cataract with no coexisting disease, 100 cases had cataract with primary open angle glaucoma and 50 cases of cataract had accompanying pseudoexfoliation glaucoma. All patients were assessed and recorded preoperatively for their IOP, vision, depth of anterior chamber (ACD), angle of anterior chamber by gonioscopy and glaucoma medications being used. Cataract surgery was performed by phacoemulsification and IOL implantations in all cases. These patients were followed up for a period of six months. Results: The intraocular ressure of all these patients was recorded at monthly interval for six months. The IOP showed a significant decrease in all cases and remained constant till the end of the study. A marked improvement of vision was noted in all cases. The depth of the anterior chamber increased and the angle also widened in all cases. Discussion: Cataract surgery has been found to reduce IOP along with improvement in vision. Patients with glaucoma have a dual benefit of reduced IOP and visual improvement after cataract surgery. (author)

Effect of pegaptanib sodium 0.3 mg intravitreal injections (Macugen) in intraocular pressure

DEFF Research Database (Denmark)

Boyer, David S; Goldbaum, Mauro; Leys, Anita M

2014-01-01

OBJECTIVE: To assess the rate of pegaptanib-associated sustained intraocular pressure (IOP) elevation. METHODS: A posthoc analysis was conducted on all IOP measurements, except the immediate 30-min postinjection, from all subjects randomised to pegaptanib 0.3 mg or sham injections continuously in...

The vascular basis of the positional influence of the intraocular pressure.

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Krieglstein, G K; Waller, W K; Leydhecker, W

1978-05-02

By measuring intraocular pressure in different body positions from 60 degrees semiupright to 30 degrees head down, a nonlinear relationship between IOP increase and body position was confirmed. IOP postural response in individual subjects was roughly correlated to ophthalmic arterial pressure and to the episcleral venous pressure postural response. In one series of subjects, the episcleral venous pressure increments due to posture wa; parallel to the applanation-indentation disparity in the same individual eyes. Differential tonometry with applanation or indentation procedures under blind conditions gave significantly low indentation readings. It is concluded that IOP postural response depends on arterial and venous vascular changes when subjects move from an erect to a horizontal body position. Blood expulsion from the choroid by indentation tonometry might be the reason that this tonometric procedure does not measure IOP changes based on vascular changes.

Circadian rhythm of blood pressure and the renin-angiotensin system in the kidney.

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Ohashi, Naro; Isobe, Shinsuke; Ishigaki, Sayaka; Yasuda, Hideo

2017-05-01

Activation of the intrarenal renin-angiotensin system (RAS) has a critical role in the pathophysiology of the circadian rhythm of blood pressure (BP) and renal injury, independent of circulating RAS. Although it is clear that the circulating RAS has a circadian rhythm, reports of a circadian rhythm in tissue-specific RAS are limited. Clinical studies evaluating intrarenal RAS activity by urinary angiotensinogen (AGT) levels have indicated that urinary AGT levels were equally low during both the daytime and nighttime in individuals without chronic kidney disease (CKD) and that urinary AGT levels were higher during the daytime than at nighttime in patients with CKD. Moreover, urinary AGT levels of the night-to-day (N/D) ratio of urinary AGT were positively correlated with the levels of N/D of urinary protein, albumin excretion and BP. In addition, animal studies have demonstrated that the expression of intrarenal RAS components, such as AGT, angiotensin II (AngII) and AngII type 1 receptor proteins, increased and peaked at the same time as BP and urinary protein excretion during the resting phase, and the amplitude of the oscillations of these proteins was augmented in a chronic progressive nephritis animal compared with a control. Thus, the circadian rhythm of intrarenal RAS activation may lead to renal damage and hypertension, which both are associated with diurnal variations in BP. It is possible that augmented glomerular permeability increases AGT excretion levels into the tubular lumen and that circadian fluctuation of glomerular permeability influences the circadian rhythm of the intrarenal RAS.

The Effect of Cataract Surgery on Circadian Photoentrainment

DEFF Research Database (Denmark)

Brøndsted, Adam Elias; Sander, Birgit; Haargaard, Birgitte

2015-01-01

of cataract surgery on circadian photoentrainment and to determine any difference between blue-blocking and neutral intraocular lenses (IOLs). DESIGN: The study was a single-center, investigator-driven, double-masked, block-randomized clinical trial. PARTICIPANTS: One eye in 76 patients with bilateral age......PURPOSE: Cataract decreases blue light transmission. Because of the selective blue light sensitivity of the retinal ganglion cells governing circadian photoentrainment, cataract may interfere with normal sleep-wake regulation and cause sleep disturbances. The purpose was to investigate the effect......-related cataract eligible for cataract surgery was included. METHODS: Intervention was cataract surgery by phacoemulsification. Patients were randomized to receive a blue-blocking or neutral IOL. MAIN OUTCOME MEASURES: Primary outcome was activation of intrinsic photosensitive ganglion cells using post...

Tafluprost once daily for treatment of elevated intraocular pressure in patients with open-angle glaucoma

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Liu Y

2012-12-01

Full Text Available Yang Liu, Weiming MaoDepartment of Cell Biology and Anatomy, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TXAbstract: Glaucoma is a leading cause of visual loss worldwide. Current antiglaucoma therapy focuses on lowering intraocular pressure to a safe level. In recent years, prostaglandin analogs have become the first-line agents for treating open angle glaucoma. Tafluprost, which was first reported in 2003, is a novel prostaglandin analog, and has been shown to be a potent ocular hypotensive agent in a number of preclinical and clinical studies. Also, its unique preservative-free formulation helps to decrease preservative-associated ocular disorders and improve patient compliance. In this review, studies from 2003 to 2012 focusing on the structure, metabolism, efficacy, and safety of tafluprost are summarized. These studies suggested that application of tafluprost once daily is a safe and effective treatment for patients with open angle glaucoma.Keywords: tafluprost, prostaglandin analog, glaucoma, intraocular pressure, preservative-free formulation

Influence of ocular perfusion pressure fluctuation on glaucoma

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Min-Zi Ren

2015-12-01

Full Text Available AIM:To investigate the influence of ocular perfusion pressure fluctuation on glaucoma. METHODS:Forty patients with primary open angle glaucoma from January 2013 to June 2015 in our hospital were used as observation group and 40 families were used as control group. Circadian fluctuation of intraocular pressure, blood pressure and ocular perfusion pressure in 24h were determined to obtain systolic ocular perfusion pressure(SOPP, diastolic ocular perfusion pressure(DOPPand mean ocular perfusion pressure(MOPP. Pearson linear correlation was used to analyze the correlation of circadian MOPP fluctuation with cup-disc ratio, mean defect(MDand the picture standard deviation(PSD. RESULTS:The fluctuation of MOPP, SOPP and DOPP of observation group were significantly higher than those of control group(Pr=-0.389, 95%CI:-0.612～-0.082; P=0.011, was positively correlated with PSD(r=0.512, 95%CI:0.139 ～0.782; P=0.008; no correlation was found between it and the vertical cup-disc ratio(r=0.115, 95%CI:0.056～0.369; P=0.355. CONCLUSION:Ocular perfusion pressure fluctuations in patients with primary open angle glaucoma may reflect the severity of the disease and may make the situation aggravating. Therefore through perfusion pressure monitor in 24h may help us understand the ocular blood flow and the development of primary open-angle glaucoma.

CLINICAL PRESENTATION OF LENS INDUCED GLAUCOMA: STUDY OF EPIDEMIOLOGY, DURATION OF SYMPTOMS, INTRAOCULAR PRESSURE AND VISUAL ACUITY

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Venkataratnam

2015-10-01

Full Text Available BACKGROUND: Lens Induced Glaucoma is a common cause of ocular morbidity. OBJECTIVES: Our study was to know the Epidemiological factors, Duration of Symptoms, Visual Acuity and Intraocular Pressure in the clinical Presentation of Lens Induced Glaucoma. MATERIALS AND METHODS : This w as a tertiary hospital based prospective study in the department of Glaucoma, Sarojini Devi Eye Hospital and Regional Institute of Ophthalmology (RIO, Osmania Medical College, Hyderabad over a period from March 2015 to August 2015. 50 Patients clinically diagnosed as Lens Induced Glaucoma (LIG were studied with the data of Age, Sex, literacy, Laterality and Rural / Urban status with the duration of symptoms, Intraocular pressure and Visual Acuity. The data was analyzed by simple statistical methods. RESULT S: 50 patients, clinically diagnosed as Lens Induced Glaucoma (LIG were studied. Age group distribution was 1(2.0% in 40 - 50yrs, 13 ( 26.0% in >50 - 60yrs, 26(52.0% in >60 - 70yrs and 10(20.0% in > 70 yrs. Sex distribution was 23(46.0% of Males and 27(54.0% of Females. Urban / Rural status was 15(30.0% of Urban and 35(70.0% of Rural. Literacy status was 7(14.0% of Literate and 43(86.0% of Illiterate. Laterality was RE in 24(48.0% and LE in 26(52.0%. Duration of the presenting symptoms before re porting to the Hospital was 12.0% in 2wks. Intraocular pressure (IOP in mm of Hg showed no case (0.0% in 20 – 40, 27(54.0% in >40 - 60 and 5(10.0% >60 wit h the Mean IOP of 42.12 mm of Hg. Visual Acuity (VA was PL +ve in 24(48.0 and HM - 3/60. CONCLUSIONS: Increasing age, female gender, rural, illiterate, and delayed reporting to the hospital after the pre senting symptoms were the common risk factors with increased Intraocular pressure and poor visual acuity in the clinical presentation of Lens induced Glaucoma.

A comparative study of intraocular pressure measurement by three tonometers in normal subjects.

Science.gov (United States)

Prabhakar, S K; Mahesh, B S; Shanthamallappa, M

2013-01-01

Contact Goldmann applanation tonometry (GAT) is gold standard for measuring intraocular pressure; however its routine use is limited by its non-portability and the need for a Slit Lamp Microscope. The Portable Perkins tonometer is also considered gold standard because it is based on the same principles as the GAT. The iCare is a newly introduced, portable, non-contact tonometer (NCT) that measures intraocular pressure (IOP) using a thin metallic probe. To evaluate reliability and accuracy of IOP measurements using iCare and Keeler Pulsair tonometers against Perkins tonometer. A comparative, randomized, prospective clinical study conducted on 166 eyes of 83 (n=83) subjects in the age group 14 to 71 years. The pressures were first recorded by iCare and Pulsair and then by Perkins. The SPSS 11.00 version was used for analysis. Mean pressures and standard deviation (+/-SD) for iCare, Pulsair and Perkins were 14.62(+/- 2.47), 14.53(+/-3.36) and 13.06(+/-2.69) and the Standard Error of the Mean (SEM) was 0.27, 0.36 and 0.30 respectively. There was a good correlation between iCare and Perkins with statistically significant difference (r=0.610, p less than 0.05). Regression analysis was performed. Using the Bland-Altman analysis 95% Limits of Agreement (LoA) for iCare and Pulsair were determined as -6.1 to 2.9 and -4.5 to 7.5 respectively. Although both tonometers overestimated the Perkins values, Pulsair showed a better agreement with Perkins tonometer than iCare tonometer. © NEPjOPH.

Circadian mechanisms of 24-hour blood pressure regulation and patterning.

Science.gov (United States)

Smolensky, Michael H; Hermida, Ramón C; Portaluppi, Francesco

2017-06-01

In most persons, blood pressure (BP) rises slowly during late sleep, increases rapidly upon morning awakening and commencement of diurnal activity, exhibits two - morning and afternoon/early evening - daytime peaks, shows a minor midday nadir, and undergoes a decline during nighttime sleep by 10-20% in systolic BP and somewhat lesser amount in diastolic BP relative to wake-time means. Nyctohemeral cycles of ambient temperature, light, noise and behaviorally driven temporal patterns in food, liquid, salt, and stimulant consumption, mental/emotional stress, posture, and physical activity intensity plus circadian rhythms of wake/sleep, pineal gland melatonin synthesis, autonomic and central nervous, hypothalamic-pituitary-adrenal, hypothalamic-pituitary-thyroid, renin-angiotensin-aldosterone, renal hemodynamic, endothelial, vasoactive peptide, and opioid systems constitute the key regulators and determinants of the BP 24 h profile. Environmental and behavioral cycles are believed to be far more influential than circadian ones. However, the facts that the: i) BP 24 h pattern of secondary hypertension, e.g., diabetes and renal disease, is characterized by absence of BP fall during sleep, and ii) scheduling of conventional long-acting medications at bedtime, rather than morning, results in much better hypertension control and vascular risk reduction, presumably because highest drug concentration coincides closely with the peak of most key circadian determinants of the BP 24 h profile, indicate endogenous rhythmic influences are of greater importance than previously appreciated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of monkey intraocular pressure by rebound tonometer

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Yu, Wenhan; Cao, Guiqun; Qiu, Jinghua; Ma, Jia; Li, Ni; Yu, Man; Yan, Naihong; Chen, Lei; Pang, Iok-Hou

2009-01-01

Purpose To evaluate the usefulness of the TonoVet™ rebound tonometer in measuring intraocular pressure (IOP) of monkeys. Methods The accuracy of the TonoVet™ rebound tonometer was determined in cannulated eyes of anesthetized rhesus monkeys where IOP was controlled by adjusting the height of a connected perfusate reservoir. To assess the applicability of the equipment through in vivo studies, the diurnal fluctuation of IOP and effects of IOP-lowering compounds were evaluated in monkeys. Results IOP readings generated by the TonoVet™ tonometer correlated very well with the actual pressure in the cannulated monkey eye. The linear correlation had a slope of 0.922±0.014 (mean±SEM, n=4), a y-intercept of 3.04±0.61, and a correlation coefficient of r2=0.97. Using this method, diurnal IOP fluctuation of the rhesus monkey was demonstrated. The tonometer was also able to detect IOP changes induced by pharmacologically active compounds. A single topical ocular instillation (15 μg) of the rho kinase inhibitor, H1152, produced a 5–6 mmHg reduction (pmonkey eye. PMID:19898690

Intraocular pressure and Schirmer tear test values in maned wolf (Chrysocyon brachyurus

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Cristiane S. Honsho

Full Text Available Abstract: The purpose of this study was to establish baseline data on lacrimal quantity (STT-1 and intraocular pressure (IOP in captive maned wolves. Ten healthy adult maned wolves were contained with a snare pole and muzzle and kept in decubitus of the left side. STT-1 measurement was performed on the lateral third of the lower conjunctival sac for one minute. The cornea was desensitized and intraocular pressure was measured with an tonopen. Average STT-1 in both eyes was 11±5mm.min-1, with no statistical difference between the left and right eye (p=0.960. Average IOP in both eyes was 20±6mmHg, with no statistical difference between the left and right eye (p=0.836. Average STT-1 was lower than, and IOP was the same as normal levels found in dogs. There was no statistical difference in the age of the animals, and STT-1 and IOP values. In the present paper, average maned wolf STT-1 levels were lower compared with those found in dogs, while the IOP was the same in maned wolves as in dogs. Due to the increased incidence in providing emergency care for maned wolf victims of road kill and fires, determination reference values of ocular parameters may improve the correct diagnosis and treatment of the disease.

CORRELATION OF INTRAOCULAR PRESSURE MEASUREMENTS WITH NON CONTACT TONOMETER AND GOLDMANN APPLANATION TONOMETRY

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Leya Sara George

2017-07-01

Full Text Available BACKGROUND A complete ophthalmologic examination includes intraocular pressure (IOP measurement, which is a routine procedure and is important for diagnosis and monitoring of glaucoma. IOP measurement is most commonly done using Goldmann Applanation tonometer and Non-Contact tonometer. MATERIALS AND METHODS In this study IOP measurements of 500 eyes (glaucomatous and non-glaucomatous were performed using GAT and NCT on patients visiting the outpatient clinic of Department of Ophthalmology at Christian Medical College and Hospital, Ludhiana. This was a cross sectional and observational study. Comparison of IOP values was done in different IOP ranges. CCT was measured and analysis of its correlation with GAT and NCT was done. RESULTS Both methods of tonometry correlated significantly in patients with IOP <24 mm Hg. The mean IOP measured by NCT, was 16.06 ± 5.85 mm Hg and the mean IOP measurement by GAT was 16.61 ± 6.94 mm Hg. Intraocular pressure readings with GAT and NCT positively correlated with CCT. CONCLUSION NCT may be useful for screening in clinical settings but borderline high IOP readings should be confirmed with GAT. Our findings, also suggest that CCT is an essential variable to consider in interpreting IOP readings.

A Case of Iris Melanocytoma Demonstrating Diffuse Melanocytic Proliferation with Uncontrolled Intraocular Pressure

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Mami Kusunose

2017-03-01

Full Text Available We report a rare case with histologically proven melanocytoma of the iris that demonstrated diffuse melanocytic proliferation with uncontrolled secondary glaucoma and investigate the etiology of the intraocular pressure elevation. The patient was a 78-year-old man with a history of darkened iris of his left eye. The intraocular pressure was 39 mm Hg. A slit-lamp examination showed a diffuse darkened iris, and a gonioscopic examination revealed open angle with circumferential heavy pigmentation. There was no pigment dispersion of the anterior chamber and no pigment deposition of the cornea. We suspected malignant ring melanoma in the left eye and enucleated it. The globe was examined with light and electron microscopy. Light microscopy revealed the presence of heavily pigmented tumor cells in the iris, ciliary body, trabecular meshwork, and Schlemm’s canal. A bleached preparation showed large tumor cells with central and paracentral nuclei without mitosis. Electron microscopy of the trabecular meshwork revealed melanin-bearing tumor cells invading the intertrabecular spaces, and the melanin granules were not phagocytosed in the trabecular cells. The mechanical obstruction of the aqueous flow by the tumor cells may be a major cause of secondary glaucoma in eyes with iris melanocytoma presenting diffuse proliferation.

21 CFR 886.4270 - Intraocular gas.

Science.gov (United States)

2010-04-01

... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4270 Intraocular gas. (a) Identification. An intraocular gas is a device consisting of a gaseous fluid intended to be introduced into the eye to place pressure... required. As of May 28, 1976, an approval under section 515 of the act is required before this device may...

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

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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.

Reproducibility of ambulatory blood pressure values and circadian blood pressure patterns in untreated subjects in a 1-11 month interval.

Science.gov (United States)

Monte, Miguel; Cambão, Mariana; Mesquita Bastos, José; Polónia, Jorge

2015-11-01

To evaluate in untreated subjects the reproducibility of mean values and four circadian patterns between two ambulatory blood pressure monitoring (ABPM) recordings separated by 1-11 months. We performed a retrospective analysis of 481 individuals (59% women) evaluated by ABPM on two occasions, visit 1 (V1) and 2 (V2), separated by 5.5+0.2 months. Four circadian patterns were defined by night/day systolic blood pressure (SBP) ratios: reverse dippers (RD), ratio >1.0; non-dippers (ND), ratio 0.9-1.0; dippers (D), ratio 0.8-patterns were calculated by the percentage of the same profile from V1 to V2. Mean 24-h blood pressure (BP) at V1 and V2 was 126.8/75.9±0.5/0.5 vs. 126.5/75.7±0.5/0.4 mmHg (NS). Nighttime SBP fall was 9.8±0.4 (V1) and 9.6±0.3% (V2) (NS). The correlation coefficient of ABPM data at V1 vs. at V2 was 0.41-0.69 (ppatterns. Copyright © 2015 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Associação entre dois diferentes tipos de estrangulamento com a variação da pressão intraocular em atletas de jiu-jitsu Association between two different types of strangling and intraocular pressure variation in jiu-jitsu athletes

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Marinho Jorge Scarpi

2009-06-01

Full Text Available OBJETIVO: Verificar a associação entre dois diferentes tipos de estrangulamento com a variação da pressão intraocular em atletas de jiu-jitsu. MÉTODO: Estudo observacional em grupo de 9 atletas de jiu-jitsu, com mínimo 6 meses de treinamento, sexo masculino, idades entre 20 e 30 anos, sem presença de lesões físicas e do bulbo ocular. Buscou-se associação entre a variação da pressão intraocular e os estrangulamentos Frontal da Guarda (E1 e Frontal da Montada (E2. A pressão intraocular foi determinada com o tonômetro de Perkins, inicialmente sem que o atleta tivesse realizado atividade física nas 24 horas antecedentes e após cada golpe. Realizou-se medidas da pressão intraocular por 12 minutos, uma a cada 3 minutos de recuperação (R1; R2; R3; R4, com o indivíduo deitado. Como procedimento estatístico foi empregado o teste ANOVA e o pós-teste de Bonferroni. RESULTADOS: Ocorreu redução significativa da pressão intraocular em ambos os olhos durante a situação E2 comparada a E1 em todos os momentos da aferição de recuperação: R1 (OD: 8,22 ± 1,39 vs.11,33 ± 2,00 / OE: 8,55 ± 1,23 vs. 11,88 ± 1,90, R2 (OD: 8,44 ± 1,87 vs.10,22 ± 2,53 / OE: 9,00 ± 1,80 vs. 10,44 ± 2,35, R3 (OD: 8,44 ± 1,74 vs.9,78 ± 2,54 / OE: 8,55 + 1,42 vs. 10,33 ± 1,93 todos com pPURPOSE: To verify the association between two different types of strangling with intraocular pressure variation in jiu-jitsu athletes. METHODS: An observational study was performed on 9 athletes of jiu-jitsu, with at least 6 month of training, male, aged 20 to 30 years, without any physical and eyeball lesions. Associations between intraocular pressure and Cross Choke from the guard strangling (E1, and E2 - Cross Choke from mount strangling were gotten. Intraocular pressure was determined by using Perkins tonometer, at first in the absence of physical exercise over the last 24 hours and after each strangling. Then it was carried out the intraocular pressure

Reliable intraocular pressure measurement using automated radio-wave telemetry

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Paschalis EI

2014-01-01

Full Text Available Eleftherios I Paschalis,* Fabiano Cade,* Samir Melki, Louis R Pasquale, Claes H Dohlman, Joseph B CiolinoMassachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA*These authors contributed equally to this workPurpose: To present an autonomous intraocular pressure (IOP measurement technique using a wireless implantable transducer (WIT and a motion sensor.Methods: The WIT optical aid was implanted within the ciliary sulcus of a normotensive rabbit eye after extracapsular clear lens extraction. An autonomous wireless data system (AWDS comprising of a WIT and an external antenna aided by a motion sensor provided continuous IOP readings. The sensitivity of the technique was determined by the ability to detect IOP changes resulting from the administration of latanoprost 0.005% or dorzolamide 2%, while the reliability was determined by the agreement between baseline and vehicle (saline IOP.Results: On average, 12 diurnal and 205 nocturnal IOP measurements were performed with latanoprost, and 26 diurnal and 205 nocturnal measurements with dorzolamide. No difference was found between mean baseline IOP (13.08±2.2 mmHg and mean vehicle IOP (13.27±2.1 mmHg (P=0.45, suggesting good measurement reliability. Both antiglaucoma medications caused significant IOP reduction compared to baseline; latanoprost reduced mean IOP by 10% (1.3±3.54 mmHg; P<0.001, and dorzolamide by 5% (0.62±2.22 mmHg; P<0.001. Use of latanoprost resulted in an overall twofold higher IOP reduction compared to dorzolamide (P<0.001. Repeatability was ±1.8 mmHg, assessed by the variability of consecutive IOP measurements performed in a short period of time (≤1 minute, during which the IOP is not expected to change.Conclusion: IOP measurements in conscious rabbits obtained without the need for human interactions using the AWDS are feasible and provide reproducible results.Keywords: IOP, pressure transducer, wireless, MEMS, implant, intraocular

Short-term intraocular pressure changes after intravitreal injection of bevacizumab in diabetic retinopathy patients

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Farhood QK

2014-03-01

Full Text Available Qasim Kadhim Farhood,1 Sinan Mohammad Twfeeq21College of Medicine, Babylon University, Babylon; 2Al-Jumhori teaching hospital, Mosul, IraqBackground: This study examined the changes in short-term intraocular pressure (IOP in a prospective series of patients undergoing intravitreal bevacizumab injection. The aim was to evaluate the frequency and predictive factors related to intraocular pressure (IOP elevation in patients receiving intravitreal bevacizumab.Patients and methods: This study included 52 patients with diabetic retinopathy between 28 to 75 years of age with a mean age of 51 years; 30 (58% were females, and 22 (42% were males. All patients received bevacizumab (1.25 mg/0.05 mL injected intravitreally in a standard fashion between May 2012 to February 2013 in the AL-Jumhoury teaching hospital. IOP was measured at baseline, 5, 10, and 30 minutes after injection using Goldman applanation tonometry.Statistics: Data were analyzed using the SPSS v.12.0 for windows. Basic, demographic, and clinical data were analyzed using means, proportions, and appropriate 95% confidence intervals (CIs.Results: Most patients (85% were diagnosed with proliferative diabetic retinopathy, while 15% presented with diabetic macular edema. The mean IOP values at baseline, 5, 10, and 30 minutes after injection were 14.0 mmHg (95% CI 13.4–14.7, 36.1 mmHg (95% CI 33.5–38.6, 25.7 mmHg (95% CI 23.8–27.5, and 15.5 mmHg (95% CI 12.4–16.51, respectively. Regression analysis showed a trend toward phakic patients having higher IOP at 30 minutes.Conclusion: Intravitreal injection of bevacizumab is safe with respect to short-term IOP changes, as almost all IOP returned to a safe range (<25 mmHg within 30 minutes. Elevated IOP 30 minutes after injection only occurs rarely, so routine prophylactic use of anti-glaucoma medication is not indicated.Keywords: intravitreal injection, bevacizumab, intraocular pressure, Goldmann applanation tonometry

Genome-wide analysis of multi-ancestry cohorts identifies new loci influencing intraocular pressure and susceptibility to glaucoma

NARCIS (Netherlands)

Hysi, Pirro G.; Cheng, Ching-Yu; Springelkamp, Henriet; Macgregor, Stuart; Bailey, Jessica N. Cooke; Wojciechowski, Robert; Vitart, Veronique; Nag, Abhishek; Hewitt, Alex W.; Hohn, Rene; Venturini, Cristina; Mirshahi, Alireza; Ramdas, Wishal D.; Thorleifsson, Gudmar; Vithana, Eranga; Khor, Chiea-Chuen; Stefansson, Arni B.; Liao, Jiemin; Haines, Jonathan L.; Amin, Najaf; Wang, Ya Xing; Wild, Philipp S.; Ozel, Ayse B.; Li, Jun Z.; Fleck, Brian W.; Zeller, Tanja; Staffieri, Sandra E.; Teo, Yik-Ying; Cuellar-Partida, Gabriel; Luo, Xiaoyan; Allingham, R. Rand; Richards, Julia E.; Senft, Andrea; Karssen, Lennart C.; Zheng, Yingfeng; Bellenguez, Celine; Xu, Liang; Iglesias, Adriana I.; Wilson, James F.; Kang, Jae H.; van Leeuwen, Elisabeth M.; Jonsson, Vesteinn; Thorsteinsdottir, Unnur; Despriet, Dominiek D. G.; Ennis, Sarah; Moroi, Sayoko E.; Martin, Nicholas G.; Jansonius, Nomdo M.; Yazar, Seyhan; Tai, E-Shyong

2014-01-01

Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma, and variability in IOP might herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma

Effect of oral administration of carprofen on intraocular pressure in normal dogs.

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Meekins, J M; Overton, T L; Rankin, A J; Roush, J K

2016-08-01

The aim of this study was to determine the effect of oral administration of carprofen on intraocular pressure in normal dogs. Twelve young adult beagle dogs were randomly assigned to treatment (n = 6) or control (n = 6) groups. After an 11-day acclimation period, the treatment group received approximately 2.2 mg/kg carprofen per os every 12 h for 7 days, and the control group received a placebo gel capsule containing no drug per os every 12 h for 7 days. Intraocular pressure (IOP) was measured by a rebound tonometer at three time points per day (8 am, 2 pm, and 8 pm) during the acclimation (days 1-11) and treatment (days 12-18) phases and for 48 h (days 19-20) after the completion of treatment. There was no statistically significant change in IOP for either eye in the dogs receiving oral carprofen during the treatment phase (days 12-18). After day 4, no significant daily IOP changes were seen in control group dogs. Carprofen administered orally every 12 h for 7 days had no effect on IOP in normal beagle dogs. An acclimation period to frequent IOP measurements of at least 5 days is necessary to establish baseline IOP values and minimize possible anxiety-related effects on IOP measurements. © 2016 John Wiley & Sons Ltd.

Meta-analysis of timolol on diurnal and nighttime intraocular pressure and blood pressure.

LENUS (Irish Health Repository)

Lee, Princeton Wen-Yuan

2012-02-01

PURPOSE: To evaluate the nighttime intraocular pressure (IOP) and blood pressure (BP) response to timolol treatment in patients with ocular hypertension or primary open-angle glaucoma. METHODS: This was a meta-analysis of previously published studies that must have been randomized, prospective, crossover or parallel, single or double-masked trials. The treatment period must have been >\\/=2 weeks with >\\/=19 patients per treatment arm for a crossover, and >\\/=50 patients for a parallel designed trial. Studies must have included both baseline and treated 24-hour curves. RESULTS: For the IOP analysis, we included 8 articles with 340 patients. A reduction from baseline was observed for timolol at each time point and for the 24-hour curve (p<\\/=0.009). When 2 studies, in which timolol was used adjunctively, were removed, a similar difference was observed as above at each time point and for the 24-hour curve (p<\\/=0.003). In 2 studies, there were small reductions from baseline for the mean diastolic and systolic BPs at most time points and for the 24-hour curve (3.9 and 4.2 mmHg, respectively) with timolol treatment. The ocular perfusion pressure did not show any difference between baseline and timolol treatment at any time point or for the 24-hour curve (p>0.05). CONCLUSIONS: This meta-analysis suggests that topical timolol therapy provides an ocular hypotensive effect over the 24-hour curve, including the nighttime hours, and while small reductions in the systolic and diastolic pressures occur, the ocular perfusion pressure is not altered over 24 hours.

Survey of ophthalmic anterior segment findings and intraocular pressure in 95 North American box turtles (Terrapene spp.).

Science.gov (United States)

Espinheira Gomes, Filipe; Brandão, João; Sumner, Julia; Kearney, Michael; Freitas, Inês; Johnson, James; Cutler, Daniel; Nevarez, Javier

2016-03-01

To describe the ophthalmic biomicroscopy findings and intraocular pressures (IOP) in a captive population of box turtles and to determine whether a relationship exists between body morphometrics or health status and IOP. Hundred and three box turtles (69 Gulf coast, 24 three-toed, one ornate, one eastern, and eight unidentified) were triaged into three different color-coded groups: green (healthy), yellow (abnormal physical examination with no need for immediate care), and red (immediate care required). Both eyes were evaluated by rebound tonometry and slit-lamp biomicroscopy. Body weight and morphometric data were recorded. Intraocular pressures measurements were available for 190 eyes, slit-lamp biomicroscopy was available for 170 eyes, and morphometric data were available for 81 turtles. IOP in Gulf coast turtles (138 eyes) was 6.7 ± 1.4 mmHg OU. IOP in three-toed turtles (48 eyes) was 8.3 ± 1.5 mmHg OU, which was significantly higher than in Gulf coast turtles (P turtles only. There was a mild negative correlation between morphometrics and IOP in Gulf coast and three-toed turtles. Fifteen of 87 turtles had unilateral corneal or lenticular opacities; 3/87 had bilateral corneal or lenticular disease; and 3/87 had adnexal abnormalities. Different subspecies of box turtles have different normal intraocular pressures as measured by rebound tonometry, which was influenced by the animals' health status in one subspecies. Some morphometric parameters were found to be associated with IOP. Box turtles are often affected with ophthalmic abnormalities of unknown clinical significance. © 2015 American College of Veterinary Ophthalmologists.

Estimated Trans-Lamina Cribrosa Pressure Differences in Low-Teen and High-Teen Intraocular Pressure Normal Tension Glaucoma: The Korean National Health and Nutrition Examination Survey

OpenAIRE

Lee, Si Hyung; Kwak, Seung Woo; Kang, Eun Min; Kim, Gyu Ah; Lee, Sang Yeop; Bae, Hyoung Won; Seong, Gong Je; Kim, Chan Yun

2016-01-01

Background To investigate the association between estimated trans-lamina cribrosa pressure difference (TLCPD) and prevalence of normal tension glaucoma (NTG) with low-teen and high-teen intraocular pressure (IOP) using a population-based study design. Methods A total of 12,743 adults (? 40 years of age) who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) from 2009 to 2012 were included. Using a previously developed formula, cerebrospinal fluid pressure (C...

Eye retraction and rotation during Corvis ST 'air puff' intraocular pressure measurement and its quantitative analysis.

Science.gov (United States)

Boszczyk, Agnieszka; Kasprzak, Henryk; Jóźwik, Agnieszka

2017-05-01

The aim of this study was to analyse the indentation and deformation of the corneal surface, as well as eye retraction, which occur during air puff intraocular pressure (IOP) measurement. A group of 10 subjects was examined using a non-contact Corvis ST tonometer, which records image sequences of corneas deformed by an air puff. Obtained images were processed numerically in order to extract information about corneal deformation, indentation and eyeball retraction. The time dependency of the apex deformation/eye retraction ratio and the curve of dependency between apex indentation and eye retraction take characteristic shapes for individual subjects. It was noticed that the eye globes tend to rotate towards the nose in response to the air blast during measurement. This means that the eye globe not only displaces but also rotates during retraction. Some new parameters describing the shape of this curve are introduced. Our data show that intraocular pressure and amplitude of corneal indentation are inversely related (r 8  = -0.83, P = 0.0029), but the correlation between intraocular pressure and amplitude of eye retraction is low and not significant (r 8  = -0.24, P = 0.51). The curves describing corneal behaviour during air puff tonometry were determined and show that the eye globe rotates towards the nose during measurement. In addition, eye retraction amplitudes may be related to elastic or viscoelastic properties of deeper structures in the eye or behind the eye and this should be further investigated. Many of the proposed new parameters present comparable or even higher repeatability than the standard parameters provided by the Corvis ST. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

Recent Advances in Circadian Rhythms in Cardiovascular System

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Lihong eChen

2015-04-01

Full Text Available Growing evidence shows that intrinsic circadian clocks are tightly related to cardiovascular functions. The diurnal changes in blood pressure and heart rate are well known circadian rhythms. Endothelial function, platelet aggregation and thrombus formation exhibit circadian changes as well. The onset of many cardiovascular diseases (CVDs or events, such as myocardial infarction, stroke, arrhythmia, and sudden cardiac death, also exhibits temporal trends. Furthermore, there is strong evidence from animal models and epidemiological studies showing that disruption of circadian rhythms is a significant risk factor for many CVDs, and the intervention of CVDs may have a time dependent effect. In this mini review, we summarized recent advances in our understanding of the relationship between circadian rhythm and cardiovascular physiology and diseases including blood pressure regulation and myocardial infarction.

Circadian variation of blood pressure in patients with chronic renal failure on continuous ambulatory peritoneal dialysis

DEFF Research Database (Denmark)

Clausen, P; Feldt-Rasmussen, B; Ladefoged, Jens

1995-01-01

The circadian pattern of blood pressure variation was investigated in 10 patients with advanced chronic renal failure on continuous ambulatory peritoneal dialysis (CAPD) and in an age-matched group of controls without renal disease with similar office blood pressure level. Monitoring was done using....... In patients with chronic renal failure undergoing CAPD, an otherwise unnoticed 24-h hypertension and nocturnal blood pressure elevation can be discovered by use of 24-h blood pressure monitoring and this may indicate a need of earlier start of antihypertensive treatment in CAPD patients with borderline...

Acute Retention of Urine Following Intraocular Surgery | Nwosu ...

African Journals Online (AJOL)

Hyperosmolar agents and carbonic anhydrase inhibitors are used to lower the intraocular pressure and thus minimize the chances of vitreous loss during intraocular surgery. However, these agents could precipitate urinary retention. This is a report on two elderly men who had perioperative acute urinary retention following ...

Effect on Intraocular Pressure of Switching from Latanoprost and Travoprost Monotherapy to Timolol Fixed Combinations in Patients with Normal-Tension Glaucoma

Directory of Open Access Journals (Sweden)

Ryoko Igarashi

2014-01-01

Full Text Available Purpose. To evaluate the effect on intraocular pressure (IOP of switching from latanoprost and travoprost monotherapy to timolol fixed combinations in Japanese patients with normal-tension glaucoma (NTG. Methods. 27 NTG patients (54 eyes were compared IOP, superficial punctuate keratitis (SPK scores, and conjunctival injection scores in eyes treated with prostaglandin (PG or PG analog/beta-blocker (PG/b fixed-combination 6 months after the change in therapy. Results. The mean baseline intraocular pressure was 17.4±1.59 mmHg in eyes receiving PG therapy only and 17.4±1.69 mmHg in eyes switched to PG/b. Switching to fixed combination therapy from PG monotherapy, the mean IOP was 13.1±1.79 mmHg (P<0.001  (-24.71% reduction from baseline at 6 months. The mean conjunctival injection score was 0.69 for eyes on PG monotherapy and 0.56 for eyes on fixed combination therapy (P=0.028. The mean SPK scores were 0.46 and 0.53. This difference was not statistically significant (P=0.463. Conclusions. Switching from PG monotherapy to PG/b fixed combination therapy for NTG resulted in a greater intraocular pressure reduction than PG alone without increasing the number of instillations.

Effect of pegaptanib sodium 0.3 mg intravitreal injections (Macugen) in intraocular pressure: posthoc analysis from VISION study

NARCIS (Netherlands)

Boyer, David S.; Goldbaum, Mauro; Leys, Anita M.; Starita, Carla; Blumenkranz, M.; Buyse, M.; Goldberg, M.; Gragoudas, E. S.; Miller, J.; Schwartz, S. D.; Singerman, L.; Yannuzzi, L.; Adamis, A. P.; Guyer, D. R.; O'Shaughnessy, D.; de Gronckel, S.; Fesneau, G.; Quinaux, E.; Tremolet, D.; Wang, K.; Brailey, A.; Finman, J.; Ting, N.; Bressler, N. M.; Bressler, S. B.; Denblow, R.; Schein, O. D.; Seabrook, S.; Solomon, S.; Schachat, A. P.; Philips, D.; Altaweel, M.; Davis, M. D.; Blodi, Ba; Danis, R. P.; Ip, M. S.; Hiner, C.; Elledge, J.; Webster, M.; Hannan, C.; Ficken, J.; Alexander, S.; Neider, M.; Wabers, H.; Vargo, P.; Lambert, E.; Kastorff, L.; Carr, A.; Shkiele, A.; Schlingemann, R. O.

2014-01-01

Objective To assess the rate of pegaptanib-associated sustained intraocular pressure (IOP) elevation. Methods A posthoc analysis was conducted on all IOP measurements, except the immediate 30-min postinjection, from all subjects randomised to pegaptanib 0.3 mg or sham injections continuously in the

Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility

NARCIS (Netherlands)

Chintalapudi, S.R. (Sumana R.); Maria, D. (Doaa); Di Wang, X. (Xiang); Bailey, J.N.C. (Jessica N. Cooke); Allingham, R. (Rand); M.H. Brilliant (Murray H.); D.L. Budenz (Donald L.); J. Fingert (John); D. Gaasterland (Douglas); T. Gaasterland (Terry); J.L. Haines (Jonathan); Hark, L. (Lisa); M.A. Hauser (Michael); R.P. Igo Jr. (Robert); Hee Kang, J. (Jae); P. Kraft (Peter); R.K. Lee (Richard K.); P.A. Lichter (Paul A.); Liu, Y. (Yutao); Moroi, S. (Syoko); L.R. Pasquale (Louis); M.A. Pericak-Vance (Margaret); A. Realini (Anthony); Rhee, D. (Doug); Richards, J.R. (Julia R.); Ritch, R. (Robert); J.S. Schuman (Joel S.); W.K. Scott (William); K. Singh (Kuldev); A.J. Sit (Arthur J.); D. Vollrath (Douglas); G. Wollstein (Gadi); D.J. Zack (Donald); T. Aung (Tin); Bonnemaijer, P. (Peter); Cheng, C.-Y. (Cheng-Yu); J.E. Craig (Jamie); C.M. van Duijn (Cornelia); P. Gharahkhani (Puya); Iglesias Gonzalez, A. (Adriana); Hammond, C.J. (Christopher J.); Hewitt, A. (Alex); Hoehn, R. (Rene); Jonansson, F. (Fridbert); A.P. Khawaja (Anthony); Chuen Khor, C. (Chiea); C.C.W. Klaver (Caroline); A.J. Lotery (Andrew); D.A. Mackey (David); MacGregor, S. (Stuart); Pang, C. (Calvin); F. Pasutto (Francesca); J-A. Zwart (John-Anker); G. Thorleifsson (Gudmar); Thorsteinsdottir, U. (Unnar); V. Vitart (Veronique); E.N. Vithana (Eranga); T.L. Young (Terri L.); T. Zeller (Tanja); P.G. Hysi (Pirro); J.L. Wiggs (Janey L.); R.W. Williams (Robert W.); Jablonski, M.M. (Monica M.)

2017-01-01

textabstractGlaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand

Appraisal of Bleb Using Trio of Intraocular Pressure, Morphology on Slit Lamp, and Gonioscopy

OpenAIRE

Thatte, Shreya; Rana, Rimpi; Gaur, Neeraj

2016-01-01

Purpose The aim of this study was to assess bleb function using Wuerzburg bleb classification score (WBCS) for bleb morphology on slit lamp, intraocular pressure (IOP), and gonioscopy. Methods A total of randomly selected 30 eyes posttrabeculectomy were assessed for bleb function with the trio of bleb morphology, IOP, and gonioscopy. Bleb was assessed using the WBCS of 0–12 on slit lamp, IOP was assessed using applanation tonometry, and visualization of inner ostium and iridectomy were assess...

Incidence of open-angle glaucoma and screening of the intraocular pressure with a non-contact tonometer.

Science.gov (United States)

Rouhiainen, H; Teräsvirta, M

1990-06-01

New equipment for measuring intraocular pressure have been introduced lately. One of these is the Keeler Pulsair non-contact tonometer which uses pressurized air in measurement. It is found to be safe and easy to use in practice, but it seems to give 1.5-2.0 mmHg lower reading than the Goldmann applanation tonometer. This was confirmed by the present study, where non-contact tonometry was controlled by applanation tonometry with a 2-3 week delay between the measurements. However, for screening procedures the accuracy of the apparatus can be considered as sufficient.

Intraocular pressure asymmetry-Topcon Computerised Tonometer CT-20.

Science.gov (United States)

Ntim-Amponsah, C T

1997-01-01

The Topcon Computerised Tonometer CT-20, a non-contact tonometer (NCT), was used to measure intraocular pressure (IOP) in mmHg in 1,226 subjects above the age of 30 years with no ocular pathology. The mean IOP was 14.41 mmHg and the standard deviation 3.43. The mean IOP far was higher in female (14.60) than male (14.22). This gender difference in the mean IOP was significant; t stat = 2.69, P < 0.5. Right IOP exceeded left IOP and this was highly significant in both male (t stat 4.03) and female (t stat 5.64) p < 0.01. This IOP asymmetry approximates a normal distribution. The mean of the differences (right-left IOP) and standard deviation for all subjects were 0.57 and 2.26 respectively. The range for the differences was- 10 to 10 mmHg. Asymmetry was greater in females than males (t stat = 2.05, p < 0.05). Knowledge of these statistics will help in decisions concerning glaucoma screening with NCT.

Effect of Anterior Chamber Depth on Intraocular Pressure after Uneventful Phacoemulsification Surgery in Nonglaucomatous Eyes with CataractEffect of Anterior Chamber Depth on Intraocular Pressure after Uneventful Phacoemulsification Surgery in Nonglaucomatous Eyes with CataractEffect of Anterior Chamber Depth on Intraocular Pressure after Uneventful Phacoemulsification Surgery in Nonglaucomatous Eyes with Cataract

Directory of Open Access Journals (Sweden)

Tansu Gönen

2011-08-01

Full Text Available Purpose: To evaluate the effect of preoperative anterior chamber depth (ACD on intraocular pressure (IOP after uneventful phacoemulsification and intraocular lens (IOL implantation in nonglaucomatous eyes. Material and Method: The medical records of fifty-five patients (30 male and 25 female were reviewed retrospectively. The patients who had undergone uneventful phacoemulsification and IOL implantation were divided into two groups according to the values of preoperative ACD: 30 eyes in group 1 (ACD≤3.27 mm and 25 eyes in group 2 (ACD>3.27 mm. IOP was measured using non-contact tonometer preoperatively and postoperatively (1 day, 1 week, 1 month, and 3 months. Results: Three months after phacoemulsification and IOL implantation, the mean IOP decreased 23.6% in group 1 and 13.7% in group 2. There was a statistically significant difference between the groups (p= 0.025. Discussion: The mean IOP decreases in eyes with shallow anterior chamber more than in normal eyes after uncomplicated phacoemulsification and IOL implantation. (Turk J Ophthalmol 2011; 41: 207-12

Comparison of levobunolol and brimonidine in prophylaxis of intraocular pressure (iop|) rise following nd: yag laser capsulotomy

International Nuclear Information System (INIS)

Habib, M.; Akram, A

2015-01-01

To compare the efficacy of topical 0.5% Levobunolol and 0.2% Brimonidine in preventing intraocular pressure rise after Nd: YAG laser posterior capsulotomy. Study Design: Randomized controlled trial (RCT). Setting and Duration of Study: Ophthalmology Department Combined Military Hospital Multan, from September 2010 to March 2011. Patients and Methods: A total of 82 patients fulfilling the inclusion criteria were selected from out-patient department and randomly divided into two equal groups. Topical 0.5% levobunolol was instilled in group A while 0.2% brimonidine was instilled in group B one hour before and immediately after doing Nd:YAG laser capsulotomy. The intraocular pressure (IOP) was measured using Goldmann applanation tonometer 1, 3 and 24 hours later. Data was analyzed using SPSS version 15.0. Results: There was no statistically significant difference in mean IOP between 0.5% Levobunolol group (Group A) and 0.2% Brimonidine group (Group B) at 1 hour, 3 hours and 24 hours after Nd:YAG laser capsulotomy. The mean intraocular pressure (IOP) one hour after Nd:YAG laser and topical treatment in group A was 16.10 ± 1.60 mmHg while in group B was 15.65 ± 3.01 mmHg (P=0.401). Mean IOP after three hours in group A was 15.80 ± 1.35 mm Hg and in group B was 15.05 ± 2.15 mmHg (p=0.062). Mean IOP after 24 hours in group A was 15.13 ± 2.05 mmHg while in group B was 14.32 ± 1.62 mmHg (p=0.058). Conclusion: Both 0.5% Levobunolol and 0.2% Brimonidine are equally effective in controlling the IOP spike after Nd: YAG laser capsulotomy. Either of these medicines can be used as a prophylaxis to prevent rise in IOP after Nd:YAG laser capsulotomy. (author)

Intraocular Inflammation Associated with Ocular Toxoplasmosis : Relationships at Initial Examination

NARCIS (Netherlands)

Dodds, Emilio M.; Holland, Gary N.; Stanford, Miles R.; Yu, Fei; Siu, Willie O.; Shah, Kayur H.; Loon, Ninette Ten Dam-Van; Muccioli, Cristina; Hovakimyan, Anna; Barisani-Asenbauer, Talin

2008-01-01

PURPOSE: To describe characteristics of intraocular inflammation in eyes with active ocular toxoplasmosis and to identify relationships between signs of inflammation, complications (including elevated intraocular pressure [IOP]), other disease features, and host characteristics. DESIGN: Multicenter,

Comparison of intraocular pressure measurements with the portable PT100 noncontact tonometer and Goldmann applanation tonometry

Directory of Open Access Journals (Sweden)

Sarwat Salim

2009-05-01

Full Text Available Sarwat Salim, Daniel J Linn, James R Echols II, Peter A NetlandHamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USAPurpose: Noncontact tonometers are useful when regulations preclude use of contact tonometers by medical students and other nonophthalmologists. Our study compared the measurements by the portable, noncontact tonometer (PT100 with Goldmann applanation tonometry (GAT. Methods: This was a prospective study of 98 eyes from 98 patients. Intraocular pressure (IOP was measured by GAT and the PT100 (Reichert, Buffalo, NY.Results: Mean IOP measurements showed no significant differences in measurements performed by the two tonometers (P = 0.64. Measurements by the two tonometers were in agreement by ≤3 mmHg in 92.8% of eyes. Linear regression analysis of PT100 vs GAT measurements revealed a slope of 0.98 with r2 = 0.58. Bland–Altman analysis showed a mean difference of measurements by GAT and PT100 of -0.3 mmHg with two standard deviation = 7.1 mmHg.Conclusion: The portable noncontact PT100 tonometer provides IOP measurements comparable to GAT within the normal range of IOP. Keywords: applanation tonometer, intraocular pressure, noncontact tonometry

Effects of tramadol and acepromazine on intraocular pressure and pupil diameter in young healthy cats

OpenAIRE

Schroder, Deise Cristine; Monteiro, Bianca Garay; Pytlak, Deborah Braga; Souza, Mayara Carvalho de; Mendonça, Adriane Jorge; Ribeiro, Alexandre Pinto

2018-01-01

ABSTRACT: This study aimed to investigate the effects of the systemic administration of acepromazine, tramadol and the association of both on intraocular pressure (IOP) and pupil diameter (PD) in young healthy cats. Cats were randomly allocated into three groups (n=10/each) and intramuscular acepromazine (AG), tramadol (TG) or acepromazine combined with tramadol (ATG) were injected. PD (electronic caliper) and IOP (applanation tonometry) were assessed before (baseline) and following 15, 30, 6...

The impact of non-dipper circadian rhythm of blood pressure on left ventricular hypertrophy in patients with non-dialysis chronic kidney disease.

Science.gov (United States)

Che, Xiajing; Mou, Shan; Zhang, Weiming; Zhang, Minfang; Gu, Leyi; Yan, Yucheng; Ying, Hua; Hu, Chunhua; Qian, Jiaqi; Ni, Zhaohui

2017-04-01

Objective The aim of this study was to investigate the correlation between non-dipper circadian rhythm of blood pressure (BP) and left ventricular hypertrophy (LVH) in patients with chronic kidney disease (CKD). Methods and results All 257 patients with stage 1 to 5 CKD were enrolled in the study and classified into a CKD1-3 group and a CKD4-5 group according to renal function. The parameters and circadian rhythm of BP were measured by a GE Marquette Tonoport V Eng dynamic sphygmomanometer, and cardiac structure was examined by echocardiography. The incidence of abnormal circadian BP rhythm (non-dipper rhythm) was quite high (75.4% in all enrolled patients and 71.3% in the patients with normal BP levels) in CKD patients and increased with the deterioration of renal function. Changes of cardiac structure such as LVH in patients with non-dipper BP were more distinct than in patients with dipper BP. The development of left ventricular mass index (LVMI) correlated positively with the incidence of non-dipper BP rhythm. Multiple regression analysis showed that 24-h systolic BP (β = 0.417, P circadian rhythm of blood pressure was quite high in CKD patients and increased with the deterioration of renal function. Non-dipper circadian rhythm of BP is closely related with LVMI.

Effect of altered eating habits and periods during Ramadan fasting on intraocular pressure, tear secretion, corneal and anterior chamber parameters

NARCIS (Netherlands)

Kerimoglu, H.; Ozturk, B.; Gunduz, K.; Bozkurt, B.; Kamis, U.; Okka, M.

Purpose To determine whether altered eating habits and periods, especially the pre-dawn meal, during Ramadan fasting have any significant effect on intraocular pressure (IOP), tear secretion, corneal and anterior chamber parameters. Methods IOP, basal tear secretion (BTS), reflex tear secretion

Data on the effects of imidazo[1,2-a]benzimidazole and pyrimido[1,2-a]benzimidazole compounds on intraocular pressure of ocular normotensive rats

Directory of Open Access Journals (Sweden)

Adrian Julian Marcus

2018-06-01

Full Text Available This data is to document the intraocular pressure (IOP lowering activity of imidazo[1,2-a]benzimidazole and pyrimido[1,2-a]benzimidazole compounds in ocular normotensive rats. Effects of single drop application of imidazo[1,2-a]benzimidazole and pyrimido[1,2-a]benzimidazole compounds on IOP in ocular normotensive rats are presented at 3 different concentrations (0.1%, 0.2% and 0.4%. Time course of changes in IOP is presented over 6 h period post-instillation. The IOP lowering activities of test compounds were determined by assessing maximum decrease in IOP from baseline and corresponding control, duration of IOP lowering and area under curve (AUC of time versus response curve. Data shown here may serve as benchmarks for other researchers studying IOP-lowering effect of imidazo[1,2-a]benzimidazole and pyrimido[1,2-a]benzimidazole compounds and would be useful in determining therapeutic potential of these test compounds as IOP lowering agents. Keywords: Drug screening, Intraocular pressure, Intraocular pressure lowering activity, Imidazo[1,2-a]benzimidazoles, Pyrimido[1,2-a]benzimidazoles, Ocular normotensive rats, Rebound tonometry

Quantitative assessment of corneal vibrations during intraocular pressure measurement with the air-puff method in patients with keratoconus.

Science.gov (United States)

Koprowski, Robert; Ambrósio, Renato

2015-11-01

One of the current methods for measuring intraocular pressure is the air-puff method. A tonometer which uses this method is the Corvis device. With the ultra-high-speed (UHS) Scheimpflug camera, it is also possible to observe corneal deformation during measurement. The use of modern image analysis and processing methods allows for analysis of higher harmonics of corneal deflection above 100 Hz. 493 eyes of healthy subjects and 279 eyes of patients with keratoconus were used in the measurements. For each eye, 140 corneal deformation images were recorded during intraocular pressure measurement. Each image was recorded every 230 µs and had a resolution of 200 × 576 pixels. A new, original algorithm for image analysis and processing has been proposed. It enables to separate the eyeball reaction as well as low-frequency and high-frequency corneal deformations from the eye response to an air puff. Furthermore, a method for classification of healthy subjects and patients with keratoconus based on decision trees has been proposed. The obtained results confirm the possibility to distinguish between patients with keratoconus and healthy subjects. The features used in this classification are directly related to corneal vibrations. They are only available in the proposed software and provide specificity of 98%, sensitivity-85%, and accuracy-92%. This confirms the usefulness of the proposed method in this type of classification that uses corneal vibrations during intraocular pressure measurement with the Corvis tonometer. With the new proposed algorithm for image analysis and processing allowing for the separation of individual features from a corneal deformation image, it is possible to: automatically measure corneal vibrations in a few characteristic points of the cornea, obtain fully repeatable measurement of vibrations for the same registered sequence of images and measure vibration parameters for large inter-individual variability in patients. Copyright © 2015 Elsevier

Effect of travoprost on 24-hour intraocular pressure in normal tension glaucoma

Directory of Open Access Journals (Sweden)

Yuya Nomura

2010-07-01

Full Text Available Yuya Nomura1, Shunsuke Nakakura2, Mitsuyasu Moriwaki1, Yasuhiro Takahashi1, Kunihiko Shiraki11Department of Ophthalmology and Visual Sciences, Graduate School of Medicine, Osaka City University, Japan; 2Department of Ophthalmology, Saiseikai Gose Hospital, JapanPurpose: The effect of travoprost 0.004% on 24-hour intraocular pressure (IOP was examined in patients with normal tension glaucoma (NTG.Subjects and methods: This study included 17 patients with newly diagnosed unilateral NTG. IOP was measured at three-hour intervals over 24 hours by Goldman applanation tonometer in patients taking topical travoprost 0.004% and was compared retrospectively with 24-hour IOP data in untreated eyes.Results: IOP values were significantly reduced at individual time points after treatment (P < 0.01. Mean 24-hour IOP, maximum 24-hour IOP, minimum 24-hour IOP, and 24-hour IOP fluctuations at baseline (mean ± SD were 12.9 ± 2.2 mmHg, 15.4 ± 2.7 mmHg, 10.5 ± 2.2 mmHg, and 4.9 ± 1.2 mmHg, respectively, and were significantly reduced to 10.3 ± 2.0 mmHg, 12.4 ± 2.5 mmHg, 8.5 ± 1.9 mmHg (all P < 0.001, and 3.9 ± 1.5 mmHg (P < 0.05, respectively, after treatment. The rate of IOP reduction greater than 20% was 58.8% (10 eyes for maximum 24-hour IOP and 53.0% (nine eyes for mean 24-hour IOP.Conclusion: Travoprost reduced IOP throughout the 24-hour study period, with over half of the eyes examined showing IOP reduction exceeding 20%.Keywords: 24-hour intraocular pressure, fluctuation, normal tension glaucoma, travoprost, Travatan Z

Nocturnal and Circadian Rhythm of Blood Pressure Is Associated with Renal Structure Damage and Function in Patients with IgAN.

Science.gov (United States)

Lin, Lirong; Zhang, Huhai; Yang, Jurong; Zhang, Jianguo; Li, Kailong; Huo, Bengang; Dai, Huanzi; Zhang, Weiwei; Yang, Jie; Tan, Wei; He, Yani

2016-01-01

Abnormal circadian rhythm of blood pressure (BP) is closely related to target organ damage in hypertension. However, the association between abnormal circadian rhythm of BP and renal injury is not clear. We investigated whether renal injury is associated with nocturnal BP and circadian rhythm of BP in Chinese IgAN patients. Clinic and 24 h ambulatory BP monitoring data were obtained from 330 Chinese IgAN patients with mean 24 h BP circadian BP, and 27% had nocturnal hypertension with a nondipping pattern. Compared with nocturnal normotensive patients, patients with nocturnal hypertension had significantly higher levels of blood cystatin C, blood uric acid, and lower estimated glomerular filtration rate (eGFR), and significantly a higher mean renal tissue injury score. The nondipping hypertensive group had significantly higher nocturnal diastolic and systolic BP, blood uric acid, and glomerulosclerosis rates, whereas eGFR was lower. In nondipping hypertensive patients, urinary sodium excretion and renal tissue injury scores were significantly higher than dipping patients. Nocturnal hypertension and abnormal circadian BP correlated with renal tissue injury, renal interstitial fibrosis, and aortic arch atherosclerosis. Abnormal circadian rhythm of BP and nocturnal hypertension are common clinical manifestations in Chinese IgAN patients with normal mean 24 h BP. Abnormal circadian BP and nocturnal hypertension may accelerate IgAN progression by inducing renal dysfunction and histopathological damage. Copyright © 2016 IMSS. Published by Elsevier Inc. All rights reserved.

High intraocular pressure produces learning and memory impairments in rats.

Science.gov (United States)

Yuan, Yuxiang; Chen, Zhiqi; Li, Lu; Li, Xing; Xia, Qian; Zhang, Hong; Duan, Qiming; Zhao, Yin

2017-11-15

Primary open angle glaucoma (POAG) is a leading cause of irreversible blindness worldwide. Previous MRI studies have revealed that POAG can be associated with alterations in hippocampal function. Thus, the aim of this study was to investigate a relationship between chronic high intraocular pressure (IOP) and hippocampal changes in a rat model. We used behavioural tests to assess learning and memory ability, and additionally investigated the hippocampal expression of pathological amyloid beta (Aβ), phospho-tau, and related pathway proteins. Chronic high IOP impaired learning and memory in rats and concurrently increased Aβ and phospho-tau expression in the hippocampus by altering the activation of different kinase (GSK-3β, BACE1) and phosphatase (PP2A) proteins in the hippocampus. This study provides novel evidence for the relationship between high IOP and hippocampal alterations, especially in the context of learning and memory. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison between 0.5% timolol maleate and 0.2% brimonidine tartrate in controlling increase in intraocular pressure after neodymium: yttrium-aluminium-garnet laser capsulotomy

International Nuclear Information System (INIS)

Tayyab, H.; Azhar, M.N.; Haider, M.A.; Jahangir, T.

2013-01-01

Objective: To compare the effectiveness of prophylactically given 0.5% Timolol maleate and 0.2% Brimonidine tartrate in controlling increase in intraocular pressure after neodymium (Nd) : yttrium aluminum garnet (YAG) laser capsulotomy. Study Design: Randomized controlled trial. Place and Duration of Study: This study was conducted at Ophthalmology Department, Jinnah Hospital, Lahore from 15-05-2009 to 14-05-2010 for a duration of 12 months. Material and Methods: In this study, 90 consecutive patients were referred from outpatient department for Nd: YAG laser capsulotomy. Hospital ethical committee's approval for this research proposal and the informed consent was taken. These patients were equally divided into two groups A and B, comprising of 45 patients in each group. Group A was control group which received 0.5% Timolol maleate. Group B was experimental group which received 0.2% Brimonidine tartrate. Intraocular pressure was measured using Goldmann tonometer before instilling these topical medications. These medications were administered topically 1 hour before the laser procedure. Intraocular pressure (IOP) was recorded 1 and 3 hours after laser capsulotomy. Results: In patients belonging to group A, 42 (93.3%) patients had effective control of IOP (raise of less than or equal to 5 mmHg from the baseline) after 3 hours of Nd:YAG laser capsulotomy whereas 28 (62.2%) patients had effective control of IOP after the same period of time in group-B with significant difference (p<0.001). Conclusion: Use of prophylactic topical antiglaucoma medications before doing Nd: YAG laser capsulotomy is a effective way to reduce post laser spike of intraocular pressure. Present study showed that the use of 0.5% timolol maleate was safe and more effective than 0.2% brimonidine tartrate when given 1 hour before laser capsulotomy. (author)

Pigment dispersion syndrome associated with intraocular lens implantation: a new surgical technique.

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Canut Jordana, M Isabel; Pérez Formigó, Daniel; Abreu González, Rodrigo; Nadal Reus, Jeroni

2010-11-11

We report the case of a myopic patient who, after intraocular lens transplant in the posterior chamber, suffered elevated intraocular pressure due to pigment dispersion, with recurrent episodes of blurred vision. The patient was treated with a new surgical technique that can avoid potential iridolenticular contact. Complete ophthalmologic examination and optical coherence tomography (OCT) of the anterior segment were performed. Contact between the pigmentary epithelium and the iris with an intraocular lens was revealed by utrasound biomicroscopy and OCT. In this case, Nd:YAG laser iridotomy and laser iridoplasty were not effective for iridolenticular separation and control of the pigment dispersion. We propose a new technique: stitches on the surface of the iris to obtain good iridolenticular separation and good intraocular pressure control. Stitches on the iris surface should be considered as optional therapy in pigmentary glaucoma secondary to intraocular lens implantation. This surgical technique can avoid potential iridolenticular contacts more definitively.

Intraocular pressure dynamics with prostaglandin analogs: a clinical application of water-drinking test

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Özyol P

2016-07-01

Full Text Available Pelin Özyol,1 Erhan Özyol,1 Ercan Baldemir2 1Ophthalmology Department, 2Biostatistics Department, Faculty of Medicine, Mugla Sitki Kocman University, Mugla, Turkey Aim: To evaluate the clinical applicability of the water-drinking test in treatment-naive primary open-angle glaucoma patients. Methods: Twenty newly diagnosed primary open-angle glaucoma patients and 20 healthy controls were enrolled in this prospective study. The water-drinking test was performed at baseline and 6 weeks and 3 months after prostaglandin analog treatment. Peak and fluctuation of intraocular pressure (IOP measurements obtained with the water-drinking test during follow-up were analyzed. Analysis of variance for repeated measures and paired and unpaired t-tests were used for statistical analysis. Results: The mean baseline IOP values in patients with primary open-angle glaucoma were 25.1±4.6 mmHg before prostaglandin analog treatment, 19.8±3.7 mmHg at week 6, and 17.9±2.2 mmHg at month 3 after treatment. The difference in mean baseline IOP of the water-drinking tests was statistically significant (P<0.001. At 6 weeks of prostaglandin analog treatment, two patients had high peak and fluctuation of IOP measurements despite a reduction in baseline IOP. After modifying treatment, patients had lower peak and fluctuation of IOP values at month 3 of the study. Conclusion: Peak and fluctuation of IOP in response to the water-drinking test were lower with prostaglandin analogs compared with before medication. The water-drinking test can represent an additional benefit in the management of glaucoma patients, especially by detecting higher peak and fluctuation of IOP values despite a reduced mean IOP. Therefore, it could be helpful as a supplementary method in monitoring IOP in the clinical practice. Keywords: glaucoma, intraocular pressure, water-drinking test, prostaglandin analog, intra­ocular pressure fluctuation

Study of the effect of distance and misalignment between magnetically coupled coils for wireless power transfer in intraocular pressure measurement.

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Rendon-Nava, Adrian E; Díaz-Méndez, J Alejandro; Nino-de-Rivera, Luis; Calleja-Arriaga, Wilfrido; Gil-Carrasco, Felix; Díaz-Alonso, Daniela

2014-01-01

An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.

Study of the Effect of Distance and Misalignment between Magnetically Coupled Coils for Wireless Power Transfer in Intraocular Pressure Measurement

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Adrian E. Rendon-Nava

2014-01-01

Full Text Available An analysis of the effect of distance and alignment between two magnetically coupled coils for wireless power transfer in intraocular pressure measurement is presented. For measurement purposes, a system was fabricated consisting of an external device, which is a Maxwell-Wien bridge circuit variation, in charge of transferring energy to a biomedical implant and reading data from it. The biomedical implant is an RLC tank circuit, encapsulated by a polyimide coating. Power transfer was done by magnetic induction coupling method, by placing one of the inductors of the Maxwell-Wien bridge circuit and the inductor of the implant in close proximity. The Maxwell-Wien bridge circuit was biased with a 10 MHz sinusoidal signal. The analysis presented in this paper proves that wireless transmission of power for intraocular pressure measurement is feasible with the measurement system proposed. In order to have a proper inductive coupling link, special care must be taken when placing the two coils in proximity to avoid misalignment between them.

Effects of simulated microgravity on circadian rhythm of caudal arterial pressure and heart rate in rats and their underlying mechanism

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Li CHEN

2016-04-01

Full Text Available Objective 　To explore the effects of simulated microgravity on the circadian rhythm of rats' caudal arterial pressure and heart rate, and their underlying mechanism. Methods 　Eighteen male SD rats (aged 8 weeks were randomly assigned to control (CON and tail suspension (SUS group (9 each. Rats with tail suspension for 28 days were adopted as the animal model to simulate microgravity. Caudal arterial pressure and heart rate of rats were measured every 3 hours. The circadian difference of abdominal aorta contraction was measured by aortic ring test. Western blotting was performed to determine and compare the protein expression level of clock genes such as Per2 (Period2, Bmal1 (Aryl hydrocarbon receptor nuclear translocatorlike and dbp (D element binding protein in suprachiasmatic nucleus (SCN and abdominal aorta of rats in CON and SUS group at different time points. Results 　Compared with CON group, the caudal arterial pressure, both systolic and diastolic pressure, decreased significantly and the diurnal variability disappeared, meanwhile the heart rate increased obviously and also the diurnal variability disappeared in rats of SUS group. Compared with CON group, the contraction reactivity of abdominal aorta decreased with disappearence of the diurnal variability, and also the clock genes expression in SCN and abdominal aorta showed no diurnal variability in rats of SUS group. Conclusion 　Simulated microgravity may lead to circadian rhythm disorders in rats' cardiovascular system, which may be associated with the changes of the clock genes expression. DOI: 10.11855/j.issn.0577-7402.2016.04.06

The Role of Low-frequency TRANS-orbital Magnetic Stimulation in Normalization of Intraocular Pressure in Patients with Primary Open-angle Glaucoma

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I. A. Makarov

2016-01-01

Full Text Available Purpose. Assessment of the effectiveness of low-frequency magnetic therapy on the dynamics of intraocular pressure in the treatment of primary and uncompensated medical means of open-angle glaucoma. Patients and Methods. 46 patients with uncompensated open-angle glaucoma. The first group: 24 patients (42 eyes with open-angle glaucoma (I, II, III stages during 2–13 years. The second group: 22 patients (22 eyes with newly diagnosed elevated intraocular pressure in one eye. The age of patients ranged from 43 to 59 years. Treatment included antiglaucoma hypotensive eye drops and TRANS-orbital magnetic stimulation on the domestic device“Polus-2”. Results. Intraocular pressure before treatment ranged from 25 to 32 mm Hg. (average of 28.9±1.4 mm Hg. in the first group . After magnetic stimulation IOP decreased within 2–5 days in all patients to 18 to 21 mm Hg (average of 17.9±1.1 mm Hg, reaching values “pressure goal.” Second group: in the primary treatment in patients IOP was 28–39 mm Hg (average of 32.6±1.8 mm Hg on one of the eyes. IOP decreased to 16–21 mm Hg in the period from 3 to 9 days in all patients of study group after daily magnetic stimulation and instillation of xalatan and timolol. In the control subgroup of patients with uncompensated openangle glaucoma loweringof the IOP to “pressure goal,” noted only in 7 patients (70,0% 11–14 days after instillation of anti-hypertensive glaucoma eye drops only. Conclusion. Low-frequency TRANS-orbital magnetic stimulation in enhanced hypotensive effect antiglaucomatous eye drops and makes it easier to achieve compensation of IOP to values “pressure goals” in patients with uncompensated open-angle glaucoma. The marked dependence of the efficiency of reduction of IOP from biotropic parameters of the magnetic field. The pulsed mode with a higher amplitude value of the magnetic induction has a more pronounced effect and makes it easier to achieve the reduction of IOP.

Digoxin derivatives with selectivity for the α2β3 isoform of Na,K-ATPase potently reduce intraocular pressure.

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Katz, Adriana; Tal, Daniel M; Heller, Dan; Habeck, Michael; Ben Zeev, Efrat; Rabah, Bilal; Bar Kana, Yaniv; Marcovich, Arie L; Karlish, Steven J D

2015-11-03

The ciliary epithelium in the eye consists of pigmented epithelial cells that express the α1β1 isoform of Na,K-ATPase and nonpigmented epithelial cells that express mainly the α2β3 isoform. In principle, a Na,K-ATPase inhibitor with selectivity for α2β3 that penetrates the cornea could effectively reduce intraocular pressure, with minimal systemic or local toxicity. We have recently synthesized perhydro-1,4-oxazepine derivatives of digoxin by NaIO4 oxidation of the third digitoxose and reductive amination with various R-NH2 substituents and identified derivatives with significant selectivity for human α2β1 over α1β1 (up to 7.5-fold). When applied topically, the most α2-selective derivatives effectively prevented or reversed pharmacologically raised intraocular pressure in rabbits. A recent structure of Na,K-ATPase, with bound digoxin, shows the third digitoxose approaching one residue in the β1 subunit, Gln84, suggesting a role for β in digoxin binding. Gln84 in β1 is replaced by Val88 in β3. Assuming that alkyl substituents might interact with β3Val88, we synthesized perhydro-1,4-oxazepine derivatives of digoxin with diverse alkyl substituents. The methylcyclopropyl and cyclobutyl derivatives are strongly selective for α2β3 over α1β1 (22-33-fold respectively), as determined either with purified human isoform proteins or intact bovine nonpigmented epithelium cells. When applied topically on rabbit eyes, these derivatives potently reduce both pharmacologically raised and basal intraocular pressure. The cyclobutyl derivative is more efficient than Latanoprost, the most widely used glaucoma drug. Thus, the conclusion is that α2β3-selective digoxin derivatives effectively penetrate the cornea and inhibit the Na,K-ATPase, hence reducing aqueous humor production. The new digoxin derivatives may have potential for glaucoma drug therapy.

New method for remote and repeatable monitoring of intraocular pressure variations.

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Margalit, Israel; Beiderman, Yevgeny; Skaat, Alon; Rosenfeld, Elkanah; Belkin, Michael; Tornow, Ralf-Peter; Mico, Vicente; Garcia, Javier; Zalevsky, Zeev

2014-02-01

We present initial steps toward a new measurement device enabling high-precision, noncontact remote and repeatable monitoring of intraocular pressure (IOP)-based on an innovative measurement principle. Using only a camera and a laser source, the device measures IOP by tracking the secondary speckle pattern trajectories produced by the reflection of an illuminating laser beam from the iris or the sclera. The device was tested on rabbit eyes using two different methods to modify IOP: via an infusion bag and via mechanical pressure. In both cases, the eyes were stimulated with increasing and decreasing ramps of the IOP. As IOP variations changed the speckle distributions reflected back from the eye, data were recorded under various optical configurations to define and optimize the best experimental configuration for the IOP extraction. The association between the data provided by our proposed device and that resulting from controlled modification of the IOP was assessed, revealing high correlation (R2=0.98) and sensitivity and providing a high-precision measurement (5% estimated error) for the best experimental configuration. Future steps will be directed toward applying the proposed measurement principle in clinical trials for monitoring IOP with human subjects.

Effects of puff times on intraocular pressure agreement between non-contact and Goldmann applanation tonometers

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Ibrahim Toprak

2014-07-01

Full Text Available AIM: To compare intraocular pressure(IOPvalues obtained from two different puff modes of Canon TX-F non-contact tonometer(NCTand Goldmann applanation tonometer(GATin patients with primary open angle glaucoma(POAG. METHODS: The study group comprised 55 right eyes of 55 patients with a confirmed diagnosis of POAG, which were under treatment. All patients underwent detailed ophthalmological examinations, optical coherence tomography imaging and automated perimetry. Intraocular pressure measurements were performed using 1-puff mode of NCT(NCT1, 3-puffs mode of NCT(NCT3and GAT with 5 minutes intervals in order. RESULTS: Fifty-five eyes of 55 patients with POAG(mean age of 64.1±8.1 yearswere enrolled into the study. NCT1 and NCT3 gave similar IOP values when compared with GAT measurements(14.22±3.42, 14.28±3.29, 14.66±3.49mmHg respectively, P=0.291. Intertonometer agreement was assessed using the Bland-Altman method. The 95% limits of agreement(LoAfor NCT1-GAT, NCT3-GAT and NCT1-NCT3 comparisons were -4.9 to +4.4mmHg, -4.1 to +3.4mmHg, and -3.4 to +3.3mmHg respectively.CONCLUSION: Although IOP measurements obtained from two puff modes of NCT and GAT showed similar values, wide range of LoA might restrict use of NCT1, NCT3 and GAT interchangeably in POAG patients.

[Comparative study of intraocular pressure measurements by Goldmann applanation tonometer, noncontact tonometer and TonoPen].

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Ceská, Burdová M; Ferrová, K; Filous, A; Oskorypová, K; Lezatková, P; Sedlácková, P

2012-02-01

The purpose of the study was to compare the levels of the intraocular pressure (NOT) measured in one eye at the same moment by three different methods: by Goldmann applanation tonometer (AT), non-contact tonometer (BT) and Tono-Pen (TP). It was further set the average variability of the performed measurements for particular tonometric methods. NOT was assessed in 106 eyes of 106 subjects aged 7-77 years (average 34.3 +/- 17.1 years). NOT was measured at the same moment with BT, TP and AT. The obtained data were statistically analyzed. The average NOT was 16.55 +/- 2.95, 17.95 +/- 4.47 and 16.13 +/- 3.4 mmHg when AT, BT and TP were applied. Average variability of three measurements for AT, BT and TP was 1.51 +/- 0.96, 1.78 +/- 1.08 and 1.47 +/- 0.9 mmHg. Average NOT levels of the measured AT and TP were almost identical with a difference of 0.42 mmHg (p = 0.236). Average level of the intraocular pressure measured by BT was higher by 1.40 mmHg and 1.82 mmHg in comparison with AT and TP (p = 0.00002), respectively. NOT measurement produced almost identical average levels at AT and TP, whereas at BT the levels were much higher. Average variability of the three subsequent NOT measurements was the highest at BT, whereas at AT and TP the average variability was lower and nearly identical.

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

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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

Effect of Hemifacial Spasm on Intraocular Pressure Measurement.

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Cicik, Erdogan; Yildirim, Rengin; Arici, Ceyhun; Dikkaya, Funda; Arslan, Osman Sevki

2018-01-01

To evaluate the effect of hemifacial spasm (HFS) on intraocular pressure (IOP) measurement. Twenty-four consecutive patients with HFS and 25 age- and gender-matched randomly selected eyes of healthy volunteers underwent corneal pachymetry and IOP measurements using Goldmann applanation tonometer (GAT) and noncontact tonometer (NCT). IOP measurements were performed before (during HFS) and 2 weeks after Botox injections in HFS patients and in healthy volunteers without Botox injections. There was no statistical difference between involved eye side and uninvolved eye side of HFS patients in measured central corneal thickness. Similarly, no difference was found between involved eye side of HFS patients and controls. There were no statistically significant differences comparing IOP values before treatment and levels measured at 2 weeks of Botox injections, either with GAT ( p = 0.33, 0.11) or NCT ( p = 0.80, 0.43) devices in the involved eyes and uninvolved eyes of patients with HFS, respectively. There were also no significant differences in these parameters (GAT ( p = 0.63) and NCT ( p = 0.54)) in controls. Contractions in facial muscles may not lead to significant increase in IOP in HFS patients. This result may help clinical decision making in the treatment of glaucoma patients with HFS. This trial is registered with NCT03390803.

Melatonin secretion is impaired in women with preeclampsia and an abnormal circadian blood pressure rhythm.

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Bouchlariotou, Sofia; Liakopoulos, Vassilios; Giannopoulou, Myrto; Arampatzis, Spyridon; Eleftheriadis, Theodoros; Mertens, Peter R; Zintzaras, Elias; Messinis, Ioannis E; Stefanidis, Ioannis

2014-08-01

Non-dipping circadian blood pressure (BP) is a common finding in preeclampsia, accompanied by adverse outcomes. Melatonin plays pivotal role in biological circadian rhythms. This study investigated the relationship between melatonin secretion and circadian BP rhythm in preeclampsia. Cases were women with preeclampsia treated between January 2006 and June 2007 in the University Hospital of Larissa. Volunteers with normal pregnancy, matched for chronological and gestational age, served as controls. Twenty-four hour ambulatory BP monitoring was applied. Serum melatonin and urine 6-sulfatoxymelatonin levels were determined in day and night time samples by enzyme-linked immunoassays. Measurements were repeated 2 months after delivery. Thirty-one women with preeclampsia and 20 controls were included. Twenty-one of the 31 women with preeclampsia were non-dippers. Compared to normal pregnancy, in preeclampsia there were significantly lower night time melatonin (48.4 ± 24.7 vs. 85.4 ± 26.9 pg/mL, pcircadian BP rhythm status ascribed this finding exclusively to non-dippers (pcircadian BP and melatonin secretion rhythm reappeared. In contrast, in cases with retained non-dipping status (n=10) melatonin secretion rhythm remained impaired: daytime versus night time melatonin (33.5 ± 13.0 vs. 28.0 ± 13.8 pg/mL, p=0.386). Urinary 6-sulfatoxymelatonin levels were, overall, similar to serum melatonin. Circadian BP and melatonin secretion rhythm follow parallel course in preeclampsia, both during pregnancy and, at least 2 months after delivery. Our findings may be not sufficient to implicate a putative therapeutic effect of melatonin, however, they clearly emphasize that its involvement in the pathogenesis of a non-dipping BP in preeclampsia needs intensive further investigation.

Dynamic association between intraocular pressure and spontaneous pulsations of retinal veins.

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Golzan, S Mojtaba; Graham, Stuart L; Leaney, John; Avolio, Alberto

2011-01-01

The amplitude of spontaneous retinal venous pulsations (SRVP) is known to be affected by intraocular pressure (IOP), retinal venous pressure, and intracranial pressure (ICP). This study characterized SRVPs adjacent to the disc and quantified changes in the amplitude of these pulsations during IOP manipulation in normal subjects. The study included 12 subjects (40 ± 15, 4 females, 8 males). Baseline IOP (range 10-25 mmHg) was measured and SRVP recorded using the dynamic retinal vessel analyzer (DVA). IOP was lowered using aproclonidine 0.5% and measured every 15 min, followed by dynamic recording of SRVP. Two subjects were also tested with timolol 0.5%, and three were treated with a placebo drop. Mean amplitude of SRVP was determined within each sample at the same site. Blood pressure and heart rate were tracked continuously. Amplitude of SRVP decreased in all subjects with reduction of IOP with aproclonidine and timolol. Mean SRVP amplitude was 8.5 ± 6 μm at baseline and reduced to 2.5 ± 1.8 μm after 45 min (p blood pressure, and heart rate did not change significantly from the baseline. Analysis of waveforms showed a slight phase shift only (150 ± 78.5 ms, p = 0.93) between disc veins and adjacent retinal vein. SRVPs in the peripapillary retina have similar waveform characteristics to those at the disc. SRVP amplitudes are reduced by manipulation of IOP downwards with pharmacological intervention. The relationship was consistent in all individuals tested for two classes of drugs and was independent of BP or heart rate changes.

A wireless intraocular pressure monitoring device with a solder-filled microchannel antenna

International Nuclear Information System (INIS)

Varel, Çağdaş; Shih, Yi-Chun; Otis, Brian P; Böhringer, Karl F; Shen, Tueng S

2014-01-01

This paper presents the prototype of an intraocular pressure sensor as a major step toward building a device that can be permanently implanted during cataract surgery. The implantation will proceed through an incision of 2–3 mm using an injector, during which the complete device must be folded into a cross-section of 2 mm × 1 mm. The device uses radio frequency (RF) for wireless power and data transfer. The prototype includes an antenna, an RF chip and a pressure sensor assembled on a printed circuit board with several circuit components used for testing and calibration. The antenna is fabricated and integrated with the circuit using a fabrication method employing solder-filled microchannels embedded in an elastomer. The monitoring device is powered at 2.716 GHz from a distance of 1–2 cm. The prototype has undergone electrical and mechanical tests for antenna and sensor performance. The flexible antenna can withstand a stress of 33.4 kPa without any electrical disconnection. It did not show a significant increase in electrical resistance after 50 bending cycles with a maximum applied stress of 116 kPa. Transmitted pressure data shows an averaged sensitivity of 16.66 Hz (mm-Hg) –1 . (paper)

Toric Intraocular Lens Outcomes in Patients With Glaucoma.

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Brown, Reay H; Zhong, Le; Bozeman, Caroline W; Lynch, Mary G

2015-06-01

To report the outcomes of toric intraocular lens implantation in patients with glaucoma and corneal astigmatism. One hundred twenty-six eyes of 87 patients with glaucoma and corneal astigmatism that underwent cataract surgery with an AcrySof toric intraocular lens (Alcon Laboratories, Inc., Fort Worth, TX) implant were selected for this single-center, retrospective case series. Corrected distance visual acuity, intraocular pressure, and refractive astigmatism were measured in each eye preoperatively and postoperatively. Uncorrected distance visual acuity and toric alignment were measured postoperatively. The uncorrected distance visual acuity was 0.04 ± 0.08 logMAR (20/22 Snellen) for all eyes. Ninety-eight percent of all eyes achieved an uncorrected distance visual acuity of 20/40 or better, with 76% achieving 20/25 or better and 47% achieving 20/20. The corrected distance visual acuity for all eyes was 0.01 ± 0.03 logMAR (20/20.5 Snellen) postoperatively. The refractive cylinder improved from 1.47 ± 1.10 diopters preoperatively to 0.31 ± 0.37 diopters postoperatively. The residual refractive cylinder was 1.00 diopter or less in 97% of eyes, 0.75 diopters or less in 90% of eyes, and 0.50 diopters or less in 83% of eyes. Mean misalignment was 4.4° ± 5.1°. Intraocular pressure decreased by a mean of 2.3 ± 3.3 mm Hg following the surgery. Toric intraocular lenses can reliably reduce astigmatism and improve uncorrected vision in eyes with cataract and glaucoma. Copyright 2015, SLACK Incorporated.

Pigment dispersion syndrome associated with intraocular lens implantation: a new surgical technique

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M Isabel Canut Jordana

2010-11-01

Full Text Available M Isabel Canut Jordana1, Daniel Pérez Formigó1, Rodrigo Abreu González2, Jeroni Nadal Reus11Barraquer Ophthalmology Centre, Barcelona, Spain; 2University Hospital of La Candelaria, Tenerife, SpainAims: We report the case of a myopic patient who, after intraocular lens transplant in the posterior chamber, suffered elevated intraocular pressure due to pigment dispersion, with recurrent episodes of blurred vision. The patient was treated with a new surgical technique that can avoid potential iridolenticular contact.Methods: Complete ophthalmologic examination and optical coherence tomography (OCT of the anterior segment were performed.Results: Contact between the pigmentary epithelium and the iris with an intraocular lens was revealed by utrasound biomicroscopy and OCT. In this case, Nd:YAG laser iridotomy and laser iridoplasty were not effective for iridolenticular separation and control of the pigment dispersion. We propose a new technique: stitches on the surface of the iris to obtain good iridolenticular separation and good intraocular pressure control.Conclusion: Stitches on the iris surface should be considered as optional therapy in pigmentary glaucoma secondary to intraocular lens implantation. This surgical technique can avoid potential iridolenticular contacts more definitively.Keywords: pigmentary glaucoma, intraocular lens, optical coherence tomography, laser

Latanoprost ophthalmic solution in the treatment of open angle glaucoma or raised intraocular pressure: a review

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Andrea Russo

2009-01-01

Full Text Available Andrea Russo, Ivano Riva, Teodoro Pizzolante, Federico Noto, Luciano QuarantaCattedra di Malattie dell’Apparato Visivo, Università degli studi di Brescia, USVD “Centro per lo studio del Glaucoma” Spedali Civili di BresciaAbstract: Latanoprost is a prostaglandin F2-alpha isopropyl ester prodrug which is rapidly hydrolyzed by esterases in the cornea to the biologically active latanoprost acid. When latanoprost is topically administered into the eye, the cornea seems to act like as a slow-release depot to the anterior segment. One hour after administration maximum concentration is found in the iris, followed by the anterior chamber and the ciliary body. Despite extensive research, controversy remains about the real mechanism of action of this drug. Immunohistochemical data have shown that the intraocular pressure (IOP reduction with topical prostaglandin F2-alpha is associated with a reduction of collagens within the uveoscleral outflow pathway. Evidence from several experimental and clinical studies suggests that latanoprost is a valuable addition first-line treatment alternatives for glaucoma, ocular hypertension and even angle-closure glaucoma. Strong points are its efficacy, which is demonstrated to be higher than that of brimonidine, dorzolamide and timolol with fewer systemic adverse effects; a convenient administration schedule; and the IOP-controlling pattern, which is relatively flat compared with timolol and dorzolamide, and enables better control in glaucoma progression, since large fluctuations may be associated with the risk of developing glaucoma in untreated ocular hypertensive subjects.Keywords: latanoprost, intraocular pressure, glaucoma, ocular hypertension

Circadian blood pressure rhythm in normotensive offspring of hypertensive parents.

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Toker, Rabia Tutuncu; Yildirim, Ali; Demir, Tevfik; Ucar, Birsen; Kilic, Zubeyir

2015-01-01

The aim of this study was to explore the circadian blood pressure (BP) rhythm using ambulatory BP monitoring (ABPM) in normotensive children with a family history of essential hypertension. Group 1 consisted of children with hypertensive mothers and/or fathers (n = 20), Group 2 consisted of children with hypertensive grandparents (n = 20), and Group 3 consisted of children with normotensive parents (n = 20). All participating children underwent a 24-h ABPM and echocardiography. Significantly higher systolic burden was found in children with hypertensive parents (p children with a family history of hypertension, a positive correlation between nocturnal systolic BP and LVMI was found, and increasing nocturnal BP values were associated with increasing LVMI (p children with a family history of hypertension, target-organ damage may precede the clinical detection of hypertension, and in those with a nocturnal non-dipper status, a more marked effect on LVMI may occur.

New intraocular pressure measurement method using reflected pneumatic pressure from cornea deformed by air puff of ring-type nozzle.

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Kim, Hyung Jin; Seo, Yeong Ho; Kim, Byeong Hee

2017-01-01

In this study, a non-contact type intraocular pressure (IOP) measuring system using reflected pneumatic pressure is proposed to overcome the disadvantages of existing measurement systems. A ring-type nozzle, a key component in the proposed system, is designed via computational fluid analysis. It predicts the reflected pneumatic pressure based on the nozzle exit angle and inner and outer diameters of the nozzle, which are 30°, 7 mm, and 9 mm, respectively. Performance evaluation is conducted using artificial eyes fabricated using polydimethylsiloxane with the specifications of human eyes. The IOP of the fabricated artificial eyes is adjusted to 10, 30, and 50 mm Hg, and the reflected pneumatic pressure is measured as a function of the distance between the ring-type nozzle and artificial eye. The measured reflected pneumatic pressure is high when the measurement distance is short and eye pressure is low. The cornea of an artificial eye is significantly deformed at a low IOP, and the applied pneumatic pressure is more concentrated in front of the ring-type nozzle because of the deformed cornea. Thus, the reflected pneumatic pressure at a low IOP has more inflows into the pressure sensor inserted inside the nozzle. The sensitivity of the output based on the IOP at measurement distances between 3-5 mm is -0.0027, -0.0022, -0.0018, -0.0015, and -0.0012. Sensitivity decreases as the measurement distance increases. In addition, the reflected pneumatic pressure owing to the misalignment at the measurement distances of 3-5 mm is not affected within a range of 0.5 mm. Therefore, the measurement range is acceptable up to a 1 mm diameter from the center of an artificial eye. However, the accuracy gradually decreases as the reflected pneumatic pressure from a misalignment of 1 mm or more decreases by 26% or more.

African Ancestry Is Associated with Higher Intraocular Pressure in Latinos.

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Nannini, Drew; Torres, Mina; Chen, Yii-Der I; Taylor, Kent D; Rotter, Jerome I; Varma, Rohit; Gao, Xiaoyi

2016-01-01

Intraocular pressure (IOP) is a major risk factor, as well as the only modifiable risk factor, for glaucoma. Racial differences have been observed in IOP measurements with individuals of African descent experiencing the highest IOP when compared with other ethnic groups. The purpose of this study was to examine the relationship between genetic ancestry and IOP in Latinos. Population-based genetic association study. A total of 3541 participants recruited from the Los Angeles Latino Eye Study. Study participants were genotyped using the Illumina OmniExpress BeadChip (∼730K markers). We used STRUCTURE to estimate individual genetic ancestry. Simple and multiple linear regression, as well as quantile regression, analyses were performed to investigate the relationship between genetic ancestry and IOP. The relationship between genetic ancestry and IOP in Latinos. African ancestry was significantly associated with higher IOP in Latinos in our simple linear regression analysis (P = 0.002). After adjusting for age, gender, body mass index, systolic blood pressure, central corneal thickness, and type 2 diabetes, this association remained significant (P = 0.0005). The main association was modified by a significant interaction between African ancestry and hypertension (P = 0.037), with hypertensive individuals experiencing a greater increase in IOP with increasing African ancestry. To our knowledge, we demonstrate for the first time that African ancestry and its interaction with hypertension are associated with higher IOP in Latinos. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Outcomes and Complications of Scleral-Fixated Intraocular Lens Combined with Ahmed Tube Surgery

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Nikhel Sachdev

2018-01-01

Full Text Available Background. To evaluate the outcome and complications of transscleral suture-fixated posterior chamber intraocular lens (PCIOL implantation combined with Ahmed glaucoma valve (AGV surgery in Asian eyes. Design. This was a retrospective study that included 22 eyes from 22 participants. The surgeries were performed at Singapore’s National University Hospital. Participants underwent an Ahmed tube surgery, together with transscleral suture-fixated posterior chamber intraocular lens. Main Outcome Measures. Complete success was defined as 6 ≤ intraocular pressure (IOP ≤ 21 mmHg without medications at the last follow-up visit, with no reoperation required and no progression to no perception of light (NPL. Results. At the last follow-up, there was a significant reduction in mean IOP (22.4 ± 6.5 mmHg versus 13.9 ± 3.9 mmHg; p<0.001 and mean number of intraocular pressure-lowering medications (2.45 ± 1.30 versus 0.05 ± 0.21; p<0.001. There was no significant change in visual acuity [1.43 ± 1.21 (LogMAR versus 1.09 ± 1.31 (p=0.204]. Sixteen eyes (72.7% achieved complete success. The 3 commonest complications were bullous keratopathy, choroidal detachment, and displacement of intraocular lens. Conclusion and Relevance. This technique showed good success for intraocular pressure control and vision preservation. Postoperative complications were relatively common although most were self-limiting. Patients at increased risk of trabeculectomy failure may be suitable for this procedure.

Intraocular pressure readings obtained through soft contact lenses using four types of tonometer

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Takenaka J

2015-10-01

Full Text Available Joji Takenaka,1 Eriko Kunihara,1 Ulfah Rimayanti,2 Junko Tanaka,3 Makoto Kaneko,4 Yoshiaki Kiuchi1 1Department of Ophthalmology and Visual Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan; 2Faculty of Medicine and Health Sciences, UIN Alauddin Makassar, South Sulawesi, Indonesia; 3Department of Epidemiology, Infectious Disease Control and Prevention, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan; 4Graduate School of Engineering, Osaka University, Osaka, Japan Purpose: To compare the reliability and accuracy of intraocular pressure (IOP measured while wearing soft contact lenses (SCLs using a non-contact tonometer (NCT, Goldmann applanation tonometer (GAT, iCare rebound tonometer (RBT and the Tono-Pen XL.Methods: Twenty-six healthy subjects were examined. The IOP was measured using NCT, GAT, RBT, and the Tono-Pen XL, while the subjects wore SCLs -5.00 D, -0.50 D and +5.00 D. Bland–Altman plots and a regression analysis were used to compare the IOPs obtained with those instruments and the IOPs of the naked eyes measured using GAT (the standard IOPs in this study.Results: The IOPs obtained by the Tono-Pen XL while the subjects were wearing -5.00 D, -0.50 D, and +5.00 D SCLs were significantly higher than those of the naked eyes obtained using GAT. RBT showed that the IOPs were similar to the GAT standard IOPs under all conditions. The IOPs measured with NCT and GAT while the subjects were wearing -5.00 D and -0.50 D SCLs were similar to the GAT standard IOPs. The IOPs obtained with RBT and NCT while the subjects were wearing -5.00 D and -0.50 D SCLs exhibited a good correlation with the standard IOPs.Conclusion: The NCT and RBT are best when measuring IOP through hydrogel SCLs. Keywords: soft contact lens, intraocular pressure, rebound tonometer, non-contact tonometer

Hypobaric Hypoxia: Effects on Intraocular Pressure and Corneal Thickness

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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.

Commercial air travel after intraocular gas injection.

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Houston, Stephen; Graf, Jürgen; Sharkey, James

2012-08-01

Passengers with intraocular gas are at risk of profound visual loss when exposed to reduced absolute pressure within the cabin of a typical commercial airliner. Information provided on the websites of the world's 10 largest airlines offer a considerable range of opinion as to when it might be safe to fly after gas injection. Physicians responsible for clearing pseassengers as 'fit to fly' should be aware modern retinal surgical techniques increasingly employ long-acting gases as vitreous substitutes. The kinetics of long-acting intraocular gases must be considered when deciding how long after surgery it is safe to travel. It is standard practice to advise passengers not to fly in aircraft until the gas is fully resorbed. To achieve this, it may be necessary to delay travel for approximately 2 wk after intraocular injection of sulfur hexafluoride (SF6) and for 6 wk after injection of perfluoropropane (C3F8).

Sutureless, Glueless, Scleral Fixation of Single-Piece and Toric Intraocular Lens: A Novel Technique

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Aditya Kelkar

2015-07-01

Full Text Available Sutureless, glueless, scleral fixation of an intraocular lens is a known technique of fixing a lens in the scleral pockets. However, this technique is applied to single-piece and toric lenses instead of 3-piece lenses, allowing the advantage of the use of premium lenses in patients with poor capsular support. Favourable results without complications of pigment dispersion, iris transillumination defects, dysphotopsia, elevated intraocular pressure, intraocular hemorrhage and cystoid macular edema with a well-centered, stable intraocular lens have been observed in the 3-month postoperative period in both cases.

Temporal evolution of intraocular pressure elevation after pupillary dilation in pigment dispersion syndrome.

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Jewelewicz, Daniel A; Radcliffe, Nathan M; Liebmann, Jeffrey; Ritch, Robert

2009-03-01

To report 4 patients with pigment dispersion syndrome (PDS) who had delayed intraocular pressure (IOP) spikes after pharmacologic pupillary dilation. Four patients with a diagnosis of PDS with documented IOP spike after pharmacologic pupillary dilation were included. Study patients were examined before and after pupillary dilation. The amount of pigment present in the anterior chamber and the IOP were measured at hourly intervals. Although maximal pigment liberation occurred immediately after maximal dilation, the IOP continued to elevate for at least 1.5 hours. The increase in IOP after pupillary dilation may not occur simultaneously with maximal pigment liberation but may follow it after the pigment has settled out of the anterior chamber. This has implications for monitoring patients with PDS after dilation to detect and treat rises in IOP.

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

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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).

Comparison of intraocular pressure measurements with the portable PT100 noncontact tonometer and goldmann applanation tonometry.

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Salim, Sarwat; Linn, Daniel J; Echols, James R; Netland, Peter A

2009-01-01

Noncontact tonometers are useful when regulations preclude use of contact tonometers by medical students and other nonophthalmologists. Our study compared the measurements by the portable, noncontact tonometer (PT100) with Goldmann applanation tonometry (GAT). This was a prospective study of 98 eyes from 98 patients. Intraocular pressure (IOP) was measured by GAT and the PT100 (Reichert, Buffalo, NY). Mean IOP measurements showed no significant differences in measurements performed by the two tonometers (P = 0.64). Measurements by the two tonometers were in agreement by tonometer provides IOP measurements comparable to GAT within the normal range of IOP.

Effects of Restricted Fructose Access on Body Weight and Blood Pressure Circadian Rhythms

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Danielle Senador

2012-01-01

Full Text Available High-fructose diet is known to produce cardiovascular and metabolic pathologies. The objective was to determine whether the timing of high fructose (10% liquid solution intake affect the metabolic and cardiovascular outcomes. Male C57BL mice with radiotelemetric probes were divided into four groups: (1 24 h water (control; (2 24 h fructose (F24; (3 12 h fructose during the light phase (F12L; (4 12 h fructose during the dark phase (F12D. All fructose groups had higher fluid intake. Body weight was increased in mice on restricted access with no difference in total caloric intake. Fasting glycemia was higher in groups with restricted access. F24 mice showed a fructose-induced blood pressure increase during the dark period. Blood pressure circadian rhythms were absent in F12L mice. Results suggest that the timing of fructose intake is an important variable in the etiology of cardiovascular and metabolic pathologies produced by high fructose consumption.

Circadian rhythms in blood pressure in free-ranging three-toed sloths (Bradypus variegatus

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Duarte D.P.F.

2003-01-01

Full Text Available Blood pressure (BP profiles were monitored in nine free-ranging sloths (Bradypus variegatus by coupling one common carotid artery to a BP telemetry transmitter. Animals moved freely in an isolated and temperature-controlled room (24ºC with 12/12-h artificial light-dark cycles and behaviors were observed during resting, eating and moving. Systolic (SBP and diastolic (DBP blood pressures were sampled for 1 min every 15 min for 24 h. BP rhythm over 24 h was analyzed by the cosinor method and the mesor, amplitude, acrophase and percent rhythm were calculated. A total of 764 measurements were made in the light cycle and 721 in the dark cycle. Twenty-four-hour values (mean ± SD were obtained for SBP (121 ± 22 mmHg, DBP (86 ± 17 mmHg, mean BP (MBP, 98 ± 18 mmHg and heart rate (73 ± 16 bpm. The SBP, DBP and MBP were significantly higher (unpaired Student t-test during the light period (125 ± 21, 88 ± 15 and 100 ± 17 mmHg, respectively than during the dark period (120 ± 21, 85 ± 17 and 97 ± 17 mmHg, respectively and the acrophase occurred between 16:00 and 17:45 h. This circadian variation is similar to that observed in cats, dogs and marmosets. The BP decreased during "behavioral sleep" (MBP down from 110 ± 19 to 90 ± 19 mmHg at 21:00 to 8:00 h. Both feeding and moving induced an increase in MBP (96 ± 17 to 119 ± 17 mmHg at 17:00 h and 97 ± 19 to 105 ± 12 mmHg at 15:00 h, respectively. The results show that conscious sloths present biphasic circadian fluctuations in BP levels, which are higher during the light period and are mainly synchronized with feeding.

A longitudinal study of age-related changes in intraocular pressure: the Kangbuk Samsung Health Study.

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Zhao, Di; Kim, Myung Hun; Pastor-Barriuso, Roberto; Chang, Yoosoo; Ryu, Seungho; Zhang, Yiyi; Rampal, Sanjay; Shin, Hocheol; Kim, Joon Mo; Friedman, David S; Guallar, Eliseo; Cho, Juhee

2014-09-02

To examine the longitudinal association between age and intraocular pressure (IOP) in a large sample of Korean men and women. We conducted a prospective cohort study of 274,064 young and middle-aged Korean adults with normal fundoscopic findings, following them from January 1, 2002, to February 28, 2010. Health exams were scheduled annually or biennially. At each visit, IOP was measured in both eyes using automated noncontact tonometers. The longitudinal change in IOP with age was evaluated using three-level mixed models for longitudinal paired-eye data, accounting for correlations between paired eyes and repeated measurements over time. In fully adjusted models, the average longitudinal change in IOP per 1-year increase in age was -0.065 mm Hg (95% confidence interval [CI] -0.068 to -0.063), with marked sex differences (P < 0.001). In men, the average annual IOP change was -0.093 mm Hg (95% CI -0.096 to -0.091) throughout follow-up. In women, the average annual IOP change was -0.006 mm Hg (95% CI -0.010 to -0.003), with a relatively flat association in the age range of 30 to 59 years and more marked annual decreases at younger and older ages. Intraocular pressure was inversely associated with age in a large cohort of Korean adults attending health-screening visits. For men, this inverse association was observed throughout the entire age range, while for women it was evident only in younger (<30 years of age) and older (≥60 years of age) women, with no association in women aged 30 to 59. Further research is needed to better understand the underlying mechanisms and to reconsider cutoffs for defining high IOP by age and sex groups in Asian populations. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Cardioprotective effects of SGLT2 inhibitors are possibly associated with normalization of the circadian rhythm of blood pressure.

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Rahman, Asadur; Hitomi, Hirofumi; Nishiyama, Akira

2017-06-01

Improvement in cardiovascular (CV) morbidity and mortality in the EMPA-REG OUTCOME study provides new insight into the therapeutic use of sodium-dependent glucose cotransporter 2 (SGLT2) inhibitors in patients with type 2 diabetes. Although SGLT2 inhibitors have several pleiotropic effects, the underlying mechanism responsible for their cardioprotective effects remains undetermined. In this regard, the absence of a nocturnal fall in blood pressure (BP), that is, non-dipping BP, is a common phenomenon in type 2 diabetes and has a crucial role in the pathogenesis of CV morbidity and mortality. In most clinical trials, SGLT2 inhibitors reduce both systolic BP (~3-5 mm Hg) and diastolic BP (~2 mm Hg) in patients with type 2 diabetes. In addition, recent clinical and animal studies have revealed that SGLT2 inhibitors enable the change in BP circadian rhythm from a non-dipper to a dipper type, which is possibly associated with the improvement in CV outcomes in patients with type 2 diabetes. In this review, recent data on the effect of SGLT2 inhibitors on the circadian rhythm of BP will be summarized. The possible underlying mechanisms responsible for the SGLT2 inhibitor-induced improvement in the circadian rhythm of BP will also be discussed.

A Longitudinal Study of Association between Adiposity Markers and Intraocular Pressure: The Kangbuk Samsung Health Study.

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Zhao, Di; Kim, Myung Hun; Pastor-Barriuso, Roberto; Chang, Yoosoo; Ryu, Seungho; Zhang, Yiyi; Rampal, Sanjay; Shin, Hocheol; Kim, Joon Mo; Friedman, David S; Guallar, Eliseo; Cho, Juhee

2016-01-01

Intraocular pressure (IOP) reduction or stabilization is the only proven method for glaucoma management. Identifying risk factors for IOP is crucial to understand the pathophysiology of glaucoma. To examine the associations of change in body mass index (BMI), waist circumference, and percent fat mass with change in intraocular pressure (IOP) in a large sample of Korean adults. Cohort study of 274,064 young and middle age Korean adults with normal fundoscopic findings who attended annual or biennial health exams from January 1, 2002 to Feb 28, 2010 (577,981 screening visits). BMI, waist circumference, and percent fat mass. At each visit, IOP was measured in both eyes with automated noncontact tonometers. In multivariable-adjusted models, the average increase in IOP (95% confidence intervals) over time per interquartile increase in BMI (1.26 kg/m2), waist circumference (6.20 cm), and percent fat mass (3.40%) were 0.18 mmHg (0.17 to 0.19), 0.27 mmHg (0.26 to 0.29), and 0.10 mmHg (0.09 to 0.11), respectively (all P < 0.001). The association was stronger in men compared to women (P < 0.001) and it was only slightly attenuated after including diabetes and hypertension as potential mediators in the model. Increases in adiposity were significantly associated with an increase in IOP in a large cohort of Korean adults attending health screening visits, an association that was stronger for central obesity. Further research is needed to understand better the underlying mechanisms of this association, and to establish the role of weight gain in increasing IOP and the risk of glaucoma and its complications.

A Longitudinal Study of Association between Adiposity Markers and Intraocular Pressure: The Kangbuk Samsung Health Study.

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Di Zhao

Full Text Available Intraocular pressure (IOP reduction or stabilization is the only proven method for glaucoma management. Identifying risk factors for IOP is crucial to understand the pathophysiology of glaucoma.To examine the associations of change in body mass index (BMI, waist circumference, and percent fat mass with change in intraocular pressure (IOP in a large sample of Korean adults.Cohort study of 274,064 young and middle age Korean adults with normal fundoscopic findings who attended annual or biennial health exams from January 1, 2002 to Feb 28, 2010 (577,981 screening visits.BMI, waist circumference, and percent fat mass.At each visit, IOP was measured in both eyes with automated noncontact tonometers.In multivariable-adjusted models, the average increase in IOP (95% confidence intervals over time per interquartile increase in BMI (1.26 kg/m2, waist circumference (6.20 cm, and percent fat mass (3.40% were 0.18 mmHg (0.17 to 0.19, 0.27 mmHg (0.26 to 0.29, and 0.10 mmHg (0.09 to 0.11, respectively (all P < 0.001. The association was stronger in men compared to women (P < 0.001 and it was only slightly attenuated after including diabetes and hypertension as potential mediators in the model.Increases in adiposity were significantly associated with an increase in IOP in a large cohort of Korean adults attending health screening visits, an association that was stronger for central obesity. Further research is needed to understand better the underlying mechanisms of this association, and to establish the role of weight gain in increasing IOP and the risk of glaucoma and its complications.

Effects of tramadol and acepromazine on intraocular pressure and pupil diameter in young healthy cats

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Deise Cristine Schroder

2018-03-01

Full Text Available ABSTRACT: This study aimed to investigate the effects of the systemic administration of acepromazine, tramadol and the association of both on intraocular pressure (IOP and pupil diameter (PD in young healthy cats. Cats were randomly allocated into three groups (n=10/each and intramuscular acepromazine (AG, tramadol (TG or acepromazine combined with tramadol (ATG were injected. PD (electronic caliper and IOP (applanation tonometry were assessed before (baseline and following 15, 30, 60, and 120 minutes of treatments. It was verified that in AG, PD decreased significantly from time point 30 to 120 (P=0.002, but such reduction did not differ significantly from baseline (P=0.89. In TG, PD increased significantly from the first 15 minutes, until the last time point of evaluation (P0.05. It can be concluded that tramadol alone or in association with acepromazine produced significant mydriasis for up to 120 minutes, without changing IOP values in normal cats. Results of this study suggested that tramadol alone or in association with acepromazine caused significant mydriasis and did not change IOP values in normal cats. Therefore, it may be considered a satisfactory pre-anesthetic combination for ophthalmic surgery in cats. However, further studies are warranted on the use of such protocols in cats with ophthalmic diseases undergoing ocular or intraocular surgery.

Homeostasis in Primates in the Hyperdynamic Environment. [circadian timekeeping and effects of lower body positive pressure on sleep

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Fuller, C. A.

1985-01-01

The influence of chronic centrifugation upon the homestatic regulation of the circadian timekeeping system was examined. The interactions of body temperature regulation and the behavioral state of arousal were studied by evaluating the influence of cephalic fluid shifts induced by lower body positive air pressure (LBPP), upon these systems. The small diurnal squirrel monkey (Saimiri sciureus) was used as the non-human primate model. Results show that the circadian timekeeping system of these primates is functional in the hyperdynamic environment, however, some of its components appear to be regulated at different homeostatic levels. The LBPP resulted in an approximate 0.7 C decrease in DBT (p 0.01). However, although on video some animals appeared drowsy during LBPP, sleep recording revealed no significant changes in state of arousal. Thus, the physiological mechanisms underlying this lowering of body temperature can be independent of the arousal state.

Effect of sedation with detomidine on intraocular pressure with and without topical anesthesia in clinically normal horses.

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Holve, Dana L

2012-02-01

To determine the effect of sedation with detomidine on intraocular pressure (IOP) in standing horses and whether topical ocular application of anesthetic alters this effect. Clinical trial. 15 clinically normal horses. Horses were assigned to group 1 (n = 7) or 2 (8). Intraocular pressure measurements were obtained at baseline (before sedation) and 10 minutes after IV administration of detomidine (0.02 mg/kg [0.009 mg/lb]). Group 1 horses had an additional IOP measurement at 20 minutes after sedation. For group 2 horses, topical ocular anesthetic was administered 10 minutes prior to baseline IOP measurements. Mean ± SD baseline IOP for horses without topical anesthesia (group 1 horses; IOP, 24.30 ± 3.09 mm Hg) was significantly lower, compared with that of horses with topical anesthesia (group 2 horses; IOP, 30.40 ± 3.25 mm Hg). Compared with baseline values, IOP at 10 minutes after sedation decreased significantly in all horses (by 3.61 ± 1.48 mm Hg and 5.78 ± 4.32 mm Hg in groups 1 and 2, respectively). In group 1 horses, IOP at 10 (20.69 ± 3.45 mm Hg) and 20 (19.96 ± 2.13 mm Hg) minutes after sedation was significantly decreased, compared with baseline values; however, the difference between IOP at 10 versus 20 minutes was not significant. The difference in IOP between group 1 and 2 horses at 10 minutes after sedation was not significant. IV administration of detomidine caused a decrease in IOP in clinically normal horses and may be a safe sedative when performing ocular procedures.

Effect of Sildenafil Citrate on Intraocular Pressure and Blood Pressure in Human Volunteers

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Gerometta, Rosana; Alvarez, Lawrence J.; Candia, Oscar A.

2011-01-01

Anecdotal reports have suggested that the vasodilator, sildenafil citrate, which evokes its effect via a select inhibition of PDE5, has the potential to increase intraocular pressure (IOP) in some individuals. An ocular hypertensive effect by sildenafil was also recently described in a sheep animal model. In contrast, clinical studies have not found a direct association between sildenafil ingestion (commonly consumed as Viagra) and changes in IOP. However, some such studies also reported no effects of sildenafil on systemic blood pressure (BP) at the time of the IOP determination. Given this surprising result, our purpose was to repeat a study in human volunteers in the city of Corrientes, Argentina to corroborate the effects of sildenafil on human IOP and systemic BP. For the present study, 9 healthy volunteers (male and female, 18 to 74 years old) were selected as subjects after ophthalmic and cardiovascular evaluation indicated that they exhibited normal parameters for their age. In a masked, placebo-controlled study, the subjects ingested 100 mg sildenafil citrate (provided as Vorst from Laboratorios Bernabo, Argentina) in one session, and a placebo on a second separate occasion. IOP was measured with a Goldman applanation tonometer by an ophthalmologist, and BP by a second physician, neither of whom witnessed the tablet ingestion by the volunteers, nor provided with information on the nature of the test compounds. A third individual administered the tablets. The average baseline IOP of this group of 9 was 13.1 ± 0.6 mm Hg. Subsequent to sildenafil ingestion, IOP increased by 26% to 16.5 ± 0.8 mm Hg 60 min later (p< 0.005, as paired data), and returned to control values within 2 hrs. Both systolic and diastolic BP were significantly reduced by sildenafil ingestion. At the point of maximal systemic hypotension (90 min), the systolic and diastolic pressures declined by 15% and 13%, respectively. No significant changes in IOP or BP were recorded after ingestion

The effect of lateral decubitus position on nocturnal intraocular pressure over a habitual 24-hour period in healthy adults.

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Hao, Jie; Zhen, Yi; Wang, Hao; Yang, Diya; Wang, Ningli

2014-01-01

To investigate the effect of lateral decubitus position (LDP) on nocturnal intraocular pressure (IOP) and the effect of LDP on 24-hour habitual IOP pattern in healthy subjects. Intraocular pressure was measured every 2-hours using an Accupen Applanation Tonometer (Accutome, USA). During the diurnal period (7:30 am, 9:30 am, 11:30 am, 1:30 pm, 3:30 pm, 5:30 pm, 7:30 pm, and 9:30 pm), IOP was measured in the sitting position under bright light (500-1000 lux) after the subjects had been seated for 5 min. The nocturnal IOP was measured in the supine position, right LDP, and left LDP, with randomized sequences, under dim light (hour habitual IOP patterns were obtained according to the nocturnal position (supine, right LDP and left LDP) for either eye. Phour period, the effect of LDP on habitual IOP pattern was not statistically significant, although the mean nocturnal IOP and the diurnal-nocturnal IOP change for the right and the left eye in the LDP pattern was slightly higher than that in the sitting-supine pattern. Significant nocturnal IOP differences existed between the dependent eye and the supine, but did not occur consistently for all time points. Over a 24-hour period, the effect of LDP on habitual IOP pattern was not statistically significant in healthy subjects.

Epicardial adipose tissue volume a diagnostic study for independent predicting disorder of circadian rhythm of blood pressure in patients with essential hypertension.

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Zhou, L; Deng, Y; Gong, J; Chen, X; Zhang, Q; Wang, J

2016-05-30

The aim of the study was to determine whether epicardial adipose tissue volume (EATV), a new cardiometabolic risk factor, is associated with circadian changes of blood pressure (BP) in patients with newly diagnosed essential hypertension. Ninety patients with newly diagnosed essential hypertension underwent ambulatory blood pressure monitoring for 24 h. EATV was measured using cardiac computed tomography. These patients were categorized into three groups according to their BP patterns (group 1, n=46, dipper hypertension, also called normal pattern; group 2, n=24, non-dipper hypertension; group 3, n=20, anti-dipper hypertension; group 2 and 3 are also called abnormal pattern). Data were collected retrospectively and compared between hypertensive patients with normal pattern and abnormal pattern. The normal pattern hypertensive patient had significant lower mean EATV and BP ((EATV, 91.3±29.4 cm3) than those of abnormal pattern patients including group 2 (EATV, 116.2±31.06cm3, EATV, 124.8±28.5cm3, PEATV with abnormal blood pressure mode was 0.500 (pEATV was elevated in newly diagnosed and untreated patients with non-dipper hypertension and anti-dipper hypertension. EATV measured by cardiac computed tomography can be used to indicate the increased risk of circadian rhythm of blood pressure.

Retropupillary iris claw intraocular lens implantation in aphakia for dislocated intraocular lens.

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Faria, Mun Yueh; Ferreira, Nuno Pinto; Pinto, Joana Medeiros; Sousa, David Cordeiro; Leal, Ines; Neto, Eliana; Marques-Neves, Carlos

2016-01-01

Nowadays, dislocated intraocular lenses (IOLs) and inadequate capsular support are becoming a challenge for every ophthalmic surgeon. Explantation of dislocated IOL and iris claw IOL (ICIOL) are the techniques that have been used in our ophthalmic department. The aim of this study is to report our technique for retropupillar ICIOL. This study is a retrospective case series. A total of 105 eyes with dislocated IOL from the patients at the Department of Ophthalmology in Santa Maria Hospital, a tertiary reference hospital in Lisbon, Portugal, from January 2012 until January 2016, had been analyzed. Of these 105 eyes, 66 eyes had dislocated one-piece IOL and 39 eyes had dislocated three-piece IOL. The latter underwent iris suture of the same IOL and were excluded from this study. The remaining 66 eyes with dislocated one-piece IOL underwent pars plana vitrectomy, that is, explantation of dislocated IOL through corneal incision and an implantation of retropupillary ICIOL. Operative data and postoperative outcomes included best corrected visual acuity, IOL position, intraocular pressure, pigment dispersion, clinical signs of endothelial cell loss, and anterior chamber depth. The mean follow-up was 23 months (range: 6-48 months). The mean preoperative best corrected visual acuity was 1.260±0.771 logMAR, and postoperative best corrected visual acuity was 0.352±0.400 logMAR units. Mean vision gain was 0.909 logMar units. The patients had the following complications: 1) retinal detachment was found in one patient, 2) corneal edema was found in three patients, 3) high intraocular pressure was observed in twelve patients, 4) subluxation of the IOL was observed in one patient, and 5) macular edema was found in three eyes. The results demonstrate that retropupillary ICIOL is an easy and effective method for the correction of aphakia in patients not receiving capsule support. The safety of this procedure must be interpreted in the context of a surgery usually indicated in

Correlation between intraocular pressure and the biometric structure of the anterior chamber in patients of chronic renal failure with hemodialysis

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Zhi-Ying Yu

2017-02-01

Full Text Available AIM: To investigate the correlation between intraocular pressure(IOPchanges pre- and post-hemodialysis(HDand the biometric structure of the anterior chamber in patients of chronic renal failure. METHODS: Fifty-two patients(take right eye as study onewith hemodialysis that were diagnosed with chronic renal failure by nephrology in our hospital from January 2015 to December 2015 were collected. Fifty-two eyes were divided into four groups based on Shaffer classification combined with ultrasound biomicroscopy(UBMand gonioscopy manifestations: wide angle group, narrow angle group, extremely narrow group and close angle group. Venous blood was collected to get plasma colloid osmotic pressure before HD and within 60s after HD. IOP was measured with rebound intraocular pressure gauge in a supine positon approximately 30min before starting HD, 2h after HD begin and approximately 30min after HD ending. Approximately 30min before and after HD, central corneal thickness was measured with corneal endothelial cell counter, central anterior chamber depth and lens thickness were taken by A scan, angle opening distance, trabecular iris angle, iris thickness and ciliary body thickness were measured by UBM. RESULTS: Plasma osmotic pressure reduced after HD, the difference was statistically significant(t=3.04, PF=41.69, PPPF=6.44, PPt=2.61, PCONCLUSION: The influence of hemodialysis on IOP is related to the biometric structure of the anterior chamber. And extremely narrow angle is risk factor of elevated IOP during hemodialysis, narrow angle may be a risk factor. While patients with wide angle is relatively safe. We suggest to take ocular examination as early as possible for patients with hemodialysis, and focus on patients with narrow angle.

Distribution of intraocular pressure and its determinants in an Iranian adult population.

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Hashemi, Hassan; Khabazkhoob, Mehdi; Emamian, Mohammad Hassan; Shariati, Mohammad; Yekta, Abbasali; Fotouhi, Akbar

2016-01-01

To determine the distribution of intraocular pressure (IOP) and its determinants in an Iranian population. In a cross-sectional survey, random cluster sampling was conducted from the 40-64 years old population of Shahroud, in the north of Iran. All participants had optometry and ophthalmic exams. IOP was determined using the Goldmann tonometry method and biometric components were measured. Of the 6311 people selected for the study, 5190 (82.2%) participated. The mean age of the participants was 50.9±6.2y and 58.7% of them were female. Mean IOP was 12.87±2.27 mm Hg. In this study 0.3% of the participants had an IOP higher than 21 mm Hg. The multiple linear regression model revealed that sex (Coef=-0.30; 95% CI: -0.43 to -0.17), diabetes (Coef=0.43; 95% CI: 0.19 to 0.67), high systolic blood pressure (Coef=0.02; 95% CI: 0.01 to 0.02), high body mass index (BMI) (Coef=0.03; 95% CI: 0.01 to 0.04), higher education (Coef=0.02, 95% CI: 0.01 to 0.04), thicker central corneal thickness (Coef=0.01; 95% CI: 0.01 to 0.02), and myopic shift in spherical equivalent (Coef=-0.14; 95% CI: -0.18 to -0.10) significantly correlated with high IOP. The IOP in this 40-64 years old population is low overall. In the north of Iran, average IOP is statistically significantly correlated with female sex, diabetes, higher BMI, systolic blood pressure, higher education, thicker cornea, and myopic refractive error.

Enhanced sodium sensitivity and disturbed circadian rhythm of blood pressure in essential hypertension.

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Uzu, Takashi; Kimura, Genjiro; Yamauchi, Atsushi; Kanasaki, Masami; Isshiki, Keiji; Araki, Shin-ichi; Sugiomoto, Toshiro; Nishio, Yoshihiko; Maegawa, Hiroshi; Koya, Daisuke; Haneda, Masakazu; Kashiwagi, Atsunori

2006-08-01

To assess whether an association between sodium-sensitive hypertension and metabolic syndrome exists; and whether, in patients with metabolic syndrome, the nocturnal fall of blood pressure decreases and salt restriction affects the circadian blood pressure rhythm. Japanese patients with essential hypertension, who were treated without any antihypertensive agent, were maintained on a high-sodium diet and a low-sodium diet for 1 week each. On the last day of each diet, the 24-h blood pressures were measured. A diagnosis of metabolic syndrome was made according to the International Diabetes Foundation definition Among the 56 patients with essential hypertension, 15 patients were complicated with metabolic syndrome while 41 patients were not. The nocturnal blood pressure fall was significant in patients without metabolic syndrome, while it was not so in patients with metabolic syndrome. Only in patients with metabolic syndrome was the nocturnal blood pressure fall enhanced by sodium restriction. The prevalence of sodium-sensitive hypertension in patients with metabolic syndrome was significantly higher than in those without metabolic syndrome (70.6 versus 36.0%, respectively; P = 0.017). A multiple logistic regression analysis revealed central obesity to be an independent risk factor for sodium-sensitive hypertension (odds ratio, 1.41; 95% confidence interval, 1.04-1.91). In patients with essential hypertension, an inter-relationship exists among metabolic syndrome, enhanced sodium sensitivity of the blood pressure and non-dipping. The elevated risk of cardiovascular diseases in patients with metabolic syndrome may be related to sodium-sensitive hypertension and non-dipping.

Intraocular pressure measurement over soft contact lens by rebound tonometer: a comparative study.

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Nacaroglu, Senay Asik; Un, Emine Seker; Ersoz, Mehmet Giray; Tasci, Yelda

2015-01-01

To evaluate the intraocular pressure (IOP) measurements by Icare rebound tonometer over a contact lens in comparison with Goldmann applanation tonometry (GAT). Fifty patients using contact lens were included in this study. One of the eyes of the patients was selected randomly and their IOP were measured by rebound tonometer with and without contact lens (RTCL, RT respectively) and by GAT, as well as their central corneal thickness (CCT) by optical pachymeter. The results of both methods were compared by correlation analysis, general linear method repeated measure and Bland-Altman analysis. Mean IOP values measured by RTCL, RT and GAT were 15.68±3.7, 14.50±3.4 and 14.16±2.8 (Pcontact lens by rebound tonometer was found to be higher than what was measured by GAT. Although this difference is statistically significant, it may be clinically negligible in the normal population.

[Effect of intraocular pressure measurement through therapeutic soft contact lenses by noncontact tonometer].

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Sugimoto-Takeuchi, R; Yamamoto, R; Kuwayama, Y; Kinoshita, S

1991-09-01

The measurement of intraocular pressure (IOP) was compared with and without soft contact lenses by a non-contact tonometer. The soft contact lenses examined were Plano-T and Plano-B4 therapeutic contact lenses and Breath-O refractive lens. Twenty-nine eyes of 18 patients with an IOP ranging from 9 to 48mmHg were studied. The measurements of IOP were 19.7 +/- 8.6mmHg with Plano-T and 18.9 +/- 9.2mmHg with Plano-B4. Both numbers were not statistically different, when compared with controls (19.3 +/- 9.8mmHg without lens). There was, however, a significant difference significant difference with (44.7 +/- 10.7mmHg) and without the Breath-O (p less than 0.01). The results suggest that accurate IOP measurements can be obtained through therapeutic soft contact lens by a non-contact tonometer.

Effect of Intra Vitreal Injection of Bevacizumab on Intra-Occular Pressure

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Jaffar, S.; Tayyab, A.; Matin, Z. I.; Masrur, A.; Naqaish, R.

2016-01-01

Background: Bevacizumab has been in use as a therapeutic agent for macular oedema for several years. While its efficacy has been well documented, its use has been shown to cause a transient rise in the intra-ocular pressure. The aim of this study was to evaluate the long term effect of intra-vitreal injection of Bevacizumab on Intra-ocular pressure. Methods: One hundred eyes (n=100) of one hundred patients, requiring intra-vitreal injection of Bevacizumab for diabetic macular oedema were recruited from Shifa Foundation Community Health Centre (SFCHC) between January and December 2014. Patients of glaucoma, ocular hyper-tension, known allergy to Bevacizumab or had injections of Bevacizumab prior to the study were excluded. Intra-ocular pressure was measured using a Goldmann applanation tonometer, prior to, and at six and twelve months after the injection. The pre- and post- injection Intra-ocular pressure was entered into the database. Test of significance was applied to investigate whether there was a significant change in intra-ocular pressure after the injection. Results: The mean age of the patient was 56.97 years (±14.97). The mean intra-ocular pressure was 13.86 (±3.16) mmHg before injection, while post-injection mean Intra-Ocular pressure was 14.21 (±3.12) mmHg and 13.79 (±3.07) at six and twelve months respectively. Between baseline and six months there was a statistically significant difference in intra-ocular pressure (p=0.03), while no significant difference existed in the intra-ocular pressure between baseline and twelve months (p=0.92). Conclusion: Intra-vitreal injection of Bevacizumab is associated with a statically significant rise in intra-ocular pressure at six months, while no significant difference was seen at twelve months compared to baseline. (author)

Analysis of the effects of non-supine sleeping positions on the stress, strain, deformation and intraocular pressure of the human eye

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Volpe, Peter A.

This thesis presents analytical models, finite element models and experimental data to investigate the response of the human eye to loads that can be experienced when in a non-supine sleeping position. The hypothesis being investigated is that non-supine sleeping positions can lead to stress, strain and deformation of the eye as well as changes in intraocular pressure (IOP) that may exacerbate vision loss in individuals who have glaucoma. To investigate the quasi-static changes in stress and internal pressure, a Fluid-Structure Interaction simulation was performed on an axisymmetrical model of an eye. Common Aerospace Engineering methods for analyzing pressure vessels and hyperelastic structural walls are applied to developing a suitable model. The quasi-static pressure increase was used in an iterative code to analyze changes in IOP over time.

Circadian light

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Bierman Andrew

2010-02-01

Full Text Available Abstract The present paper reflects a work in progress toward a definition of circadian light, one that should be informed by the thoughtful, century-old evolution of our present definition of light as a stimulus for the human visual system. This work in progress is based upon the functional relationship between optical radiation and its effects on nocturnal melatonin suppression, in large part because the basic data are available in the literature. Discussed here are the fundamental differences between responses by the visual and circadian systems to optical radiation. Brief reviews of photometry, colorimetry, and brightness perception are presented as a foundation for the discussion of circadian light. Finally, circadian light (CLA and circadian stimulus (CS calculation procedures based on a published mathematical model of human circadian phototransduction are presented with an example.

Genetic correlations between intraocular pressure, blood pressure and primary open-angle glaucoma: a multi-cohort analysis.

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Aschard, Hugues; Kang, Jae H; Iglesias, Adriana I; Hysi, Pirro; Cooke Bailey, Jessica N; Khawaja, Anthony P; Allingham, R Rand; Ashley-Koch, Allison; Lee, Richard K; Moroi, Sayoko E; Brilliant, Murray H; Wollstein, Gadi; Schuman, Joel S; Fingert, John H; Budenz, Donald L; Realini, Tony; Gaasterland, Terry; Scott, William K; Singh, Kuldev; Sit, Arthur J; Igo, Robert P; Song, Yeunjoo E; Hark, Lisa; Ritch, Robert; Rhee, Douglas J; Gulati, Vikas; Haven, Shane; Vollrath, Douglas; Zack, Donald J; Medeiros, Felipe; Weinreb, Robert N; Cheng, Ching-Yu; Chasman, Daniel I; Christen, William G; Pericak-Vance, Margaret A; Liu, Yutao; Kraft, Peter; Richards, Julia E; Rosner, Bernard A; Hauser, Michael A; Klaver, Caroline C W; vanDuijn, Cornelia M; Haines, Jonathan; Wiggs, Janey L; Pasquale, Louis R

2017-11-01

Primary open-angle glaucoma (POAG) is the most common chronic optic neuropathy worldwide. Epidemiological studies show a robust positive relation between intraocular pressure (IOP) and POAG and modest positive association between IOP and blood pressure (BP), while the relation between BP and POAG is controversial. The International Glaucoma Genetics Consortium (n=27 558), the International Consortium on Blood Pressure (n=69 395), and the National Eye Institute Glaucoma Human Genetics Collaboration Heritable Overall Operational Database (n=37 333), represent genome-wide data sets for IOP, BP traits and POAG, respectively. We formed genome-wide significant variant panels for IOP and diastolic BP and found a strong relation with POAG (odds ratio and 95% confidence interval: 1.18 (1.14-1.21), P=1.8 × 10 -27 ) for the former trait but no association for the latter (P=0.93). Next, we used linkage disequilibrium (LD) score regression, to provide genome-wide estimates of correlation between traits without the need for additional phenotyping. We also compared our genome-wide estimate of heritability between IOP and BP to an estimate based solely on direct measures of these traits in the Erasmus Rucphen Family (ERF; n=2519) study using Sequential Oligogenic Linkage Analysis Routines (SOLAR). LD score regression revealed high genetic correlation between IOP and POAG (48.5%, P=2.1 × 10 -5 ); however, genetic correlation between IOP and diastolic BP (P=0.86) and between diastolic BP and POAG (P=0.42) were negligible. Using SOLAR in the ERF study, we confirmed the minimal heritability between IOP and diastolic BP (P=0.63). Overall, IOP shares genetic basis with POAG, whereas BP has limited shared genetic correlation with IOP or POAG.

A Longitudinal Study of Association between Adiposity Markers and Intraocular Pressure: The Kangbuk Samsung Health Study

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Zhao, Di; Kim, Myung Hun; Pastor-Barriuso, Roberto; Chang, Yoosoo; Ryu, Seungho; Zhang, Yiyi; Rampal, Sanjay; Shin, Hocheol; Kim, Joon Mo; Friedman, David S.; Guallar, Eliseo; Cho, Juhee

2016-01-01

Importance Intraocular pressure (IOP) reduction or stabilization is the only proven method for glaucoma management. Identifying risk factors for IOP is crucial to understand the pathophysiology of glaucoma. Objective To examine the associations of change in body mass index (BMI), waist circumference, and percent fat mass with change in intraocular pressure (IOP) in a large sample of Korean adults. Design, setting and participants Cohort study of 274,064 young and middle age Korean adults with normal fundoscopic findings who attended annual or biennial health exams from January 1, 2002 to Feb 28, 2010 (577,981 screening visits). Exposures BMI, waist circumference, and percent fat mass. Main Outcome Measure(s) At each visit, IOP was measured in both eyes with automated noncontact tonometers. Results In multivariable-adjusted models, the average increase in IOP (95% confidence intervals) over time per interquartile increase in BMI (1.26 kg/m2), waist circumference (6.20 cm), and percent fat mass (3.40%) were 0.18 mmHg (0.17 to 0.19), 0.27 mmHg (0.26 to 0.29), and 0.10 mmHg (0.09 to 0.11), respectively (all P < 0.001). The association was stronger in men compared to women (P < 0.001) and it was only slightly attenuated after including diabetes and hypertension as potential mediators in the model. Conclusions and Relevance Increases in adiposity were significantly associated with an increase in IOP in a large cohort of Korean adults attending health screening visits, an association that was stronger for central obesity. Further research is needed to understand better the underlying mechanisms of this association, and to establish the role of weight gain in increasing IOP and the risk of glaucoma and its complications. PMID:26731527

The 24- hour pattern of intraocular pressure in suspected glaucoma patients

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Shan-Shan Li

2018-05-01

Full Text Available AIM: To analyze the value of 24-hour intraocular pressure(IOPmonitoring in suspected glaucoma patients.METHODS: Totally 48 suspected glaucoma(96 eyeswere selected for 24-hour IOP monitoring by using Accupen tonometer(24-3000and non-contact tonometer(NCT, CT-80Afrom 9:30 to 7:30 next day(once in 2h. During 07:30 to 21:30, patients were measured in sitting position, while during 23:30 to 05:30 in both sitting and supine position.RESULTS: A morning peak of IOP was shown at 7:30 in traditional position by using two measures with 22.05±3.608mmHg of NCT and 19.79±4.147mmHg of Accupen tonometer. The peak IOP in habitual position appeared in 5:30 with 21.64±4.814mmHg. The lowest IOP occurred in both position at 21:30 with 15.73±3.649mmHg. Both positions showed IOP trend of going up at night and then declining in the morning. CONCLUSION: The peak IOP in suspected glaucoma occurs mostly at early morning. Supine IOP of sleeping time is higher than that of sitting position.

Acute Central Retinal Artery Occlusion Associated with Intraocular Silicone Oil Tamponade

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Mehmet Yasin Teke

2012-05-01

Full Text Available Many systemic and ocular factors may cause acute central retinal artery occlusion (CRAO. Herein, we aimed to describe a case of CRAO due to intraocular silicone oil (SO tamponade. To the best of our knowledge, a case like our has not been reported previously. A 58-yearold male patient had undergone combined pars plana vitrectomy-lensectomy and intraocular SO for lens luxation and vitreus hemorrhage associated with a blunt ocular trauma in his right eye. Two weeks after the surgery, he presented with acute vision loss in the same eye. He was diagnosed with acute CRAO and it should be related with mechanical press or raised intraocular pressure (IOP associated with SO. He was treated by partial removal of SO immediately. In spite of the regression of retina edema, his visual acuity did not improve due to optic atrophy. SO may cause CRAO due to raised IOP and/or its mechanical pressure and this complication must be kept in mind. (Turk J Oph thal mol 2012; 42: 238-40

Intraocular Pressure And Its Determinants In Tehran Population

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Kashi AH

2005-06-01

Full Text Available Background: The aim of this study was to provide data, on the distribution or intraocular pressure (IOP in Tehran population. Materials and Methods: Through a population-based, cross-sectional study, a total of 4565 Tehran citizens were studied in the Tehran Eye Study. The findings of the participants (n=3834 10 years and older free of glaucoma diagnosis or suspicion who had undergone applanation tonometry examination are presented. All participants received a standardized protocol included applanation tonometry, and some other ocular measurements, fundus examination, demographic data and an interview. IOP measurement was used to evaluate its distribution by age, sex, and some eye parameters. ‎ Results: Mean ± SO IOP was 14.5±2.6 in the total population, 14.4±2.7 in men, and 14.5±2.5 in women. Normal range (mean±2SD of IOP was determined to be 9.3 - 19.7 mmHg. IOP increased significantly with age and cup-disc ratio except for a fall in old ages. This relationship was also observed when we analyzed individuals without diabetes or hypertension history. IOP increased with darker eye pigmentation except for blue/gray eyes. There was a non-linear ‎increase of IOP from emmetropic to high myopic eyes. ‎ Conclusion: Mean and/or normal range of IOP and their associations have been reported with wide differences in various studies. It is wise that studies evaluate IOP distribution or associations in healthy people and glaucoma people separately and also report the prevalence of IOP risk factors in their population to allow for a logical comparison of studies.

Secondhand tobacco smoke, arterial stiffness, and altered circadian blood pressure patterns are associated with lung inflammation and oxidative stress in rats.

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Gentner, Nicole J; Weber, Lynn P

2012-02-01

Chronic smoking and secondhand tobacco smoke exposure are major risk factors for cardiovascular disease that are known to adversely alter the structural and mechanical properties of arteries. The objective of this study was to determine the effects of subchronic secondhand tobacco smoke exposure on circadian blood pressure patterns, arterial stiffness, and possible sources of oxidative stress in conscious, unsedated radiotelemetry-implanted rats. Pulse wave change in pressure over time (dP/dt) was used an indicator of arterial stiffness and was compared with both structural (wall thickness) and functional (nitric oxide production and bioactivity and endothelin-1 levels) features of the arterial wall. In addition, histology of lung, heart, and liver was examined as well as pulmonary and hepatic detoxifying enzyme activity (cytochrome P450, specifically CYP1A1). Subchronic secondhand tobacco smoke exposure altered the circadian pattern of heart rate and blood pressure, with a loss in the normal dipping pattern of blood pressure during sleep. Secondhand tobacco smoke exposure also increased pulse wave dP/dt in the absence of any structural modifications in the arterial wall. Furthermore, although nitric oxide production and endothelin-1 levels were not altered by secondhand tobacco smoke, there was increased inactivation of nitric oxide as indicated by peroxynitrite production. Increased lung neutrophils or pulmonary CYP1A1 may be responsible for the increase in oxidative stress in rats exposed to secondhand tobacco smoke. In turn, this may be related to the observed failure of blood pressure to dip during periods of sleep and a possible increase in arterial stiffness.

Distribution of intraocular pressure and its determinants in an Iranian adult population

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Hashemi, Hassan; Khabazkhoob, Mehdi; Emamian, Mohammad Hassan; Shariati, Mohammad; Yekta, Abbasali; Fotouhi, Akbar

2016-01-01

AIM To determine the distribution of intraocular pressure (IOP) and its determinants in an Iranian population. METHODS In a cross-sectional survey, random cluster sampling was conducted from the 40-64 years old population of Shahroud, in the north of Iran. All participants had optometry and ophthalmic exams. IOP was determined using the Goldmann tonometry method and biometric components were measured. RESULTS Of the 6311 people selected for the study, 5190 (82.2%) participated. The mean age of the participants was 50.9±6.2y and 58.7% of them were female. Mean IOP was 12.87±2.27 mm Hg. In this study 0.3% of the participants had an IOP higher than 21 mm Hg. The multiple linear regression model revealed that sex (Coef=-0.30; 95% CI: -0.43 to -0.17), diabetes (Coef=0.43; 95% CI: 0.19 to 0.67), high systolic blood pressure (Coef=0.02; 95% CI: 0.01 to 0.02), high body mass index (BMI) (Coef=0.03; 95% CI: 0.01 to 0.04), higher education (Coef=0.02, 95% CI: 0.01 to 0.04), thicker central corneal thickness (Coef=0.01; 95% CI: 0.01 to 0.02), and myopic shift in spherical equivalent (Coef=-0.14; 95% CI: -0.18 to -0.10) significantly correlated with high IOP. CONCLUSION The IOP in this 40-64 years old population is low overall. In the north of Iran, average IOP is statistically significantly correlated with female sex, diabetes, higher BMI, systolic blood pressure, higher education, thicker cornea, and myopic refractive error. PMID:27588277

Argon laser peripheral iridoplasty versus systemic intraocular pressure-lowering medications as immediate management for acute phacomorphic angle closure

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Lee JW

2013-01-01

Full Text Available Jacky WY Lee,1 Jimmy SM Lai,1 Doris WF Yick,2 Can YF Yuen21Department of Ophthalmology, University of Hong Kong, 2Department of Ophthalmology, The Caritas Medical Centre, Kowloon West Cluster, Hong Kong, People’s Republic of ChinaBackground: The purpose of this study was to compare the efficacy and safety of argon laser peripheral iridoplasty (ALPI and systemic intraocular pressure (IOP-lowering medications in the immediate management of acute phacomorphic angle closure.Methods: Consecutive cases of acute phacomorphic angle closure were randomized to receive ALPI and an intravenous or oral carbonic anhydrase inhibitor as initial treatment. Intravenous mannitol was administered for presenting IOP > 60 mmHg or IOP > 40 mmHg 2 hours posttreatment in both arms.Results: Of 10 consecutive cases, six received medical therapy and four received ALPI. Fifty percent in the medical group and none in the ALPI group required intravenous mannitol. The ALPI group took less time to achieve IOP < 25 mmHg (18.8 ± 7.5 minutes versus 115.0 ± 97.0 minutes, P = 0.001, F test; had a greater IOP reduction within 30 minutes (69.8% ± 7.7% versus 40.9 ± 23.9%, P = 0.03, t-test; and had a consistently smaller post-attack cup to disc ratio (0.50 ± 0.02 versus 0.60 ± 0.20, P = 0.002, F test.Conclusion: ALPI offers greater safety, consistency, and efficacy than systemic IOP-lowering medications as initial treatment for phacomorphic angle closure.Keywords: phacomorphic, glaucoma, argon laser peripheral iridoplasty, medical, intraocular pressure

Twenty-four-Hour Measurement of Intraocular Pressure in Guinea Pigs (Cavia porcellus).

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Ansari-Mood, Maneli; Mehdi-Rajaei, Seyed; Sadjadi, Reza; Selk-Ghaffari, Masoud; Williams, David L

2016-01-01

The objective of this study was to measure intraocular pressure (IOP) in intact, healthy guinea pigs (15 male, 15 female) every 2 h for a 24-h period. First, IOP was measured by using rebound tonometry (RBT). After a 1-min rest period, 0.5% proparacaine ophthalmic solution, a topical anesthetic, was applied to both eyes; 4 min after anesthetic instillation, IOP was measured by using applanation tonometry (APT). The IOP was lower during the light period (0700 to 1900) than during the dark phase (2000 to 0600). The lowest IOP by both RBT and APT (3.68 and 13.37 mm Hg, respectively) occurred at 0700, whereas maximal IOP occurred at 2300 for RBT (8.12 mm Hg) but at 2100 for APT (20.62 mm Hg). No significant differences in IOP between the left and right eyes or between RBT and APT were noted. In addition, daily variations in the IOP of guinea pigs seem to be independent of sex and body weight. The results of this study may be beneficial in the diagnosis and observation of glaucoma in guinea pigs.

Upcoming methods and specifications of continuous intraocular pressure monitoring systems for glaucoma

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Amir Molaei

2018-01-01

Full Text Available Glaucoma is the leading cause of irreversible blindness and vision loss in the world. Although intraocular pressure (IOP is no longer considered the only risk factor for glaucoma, it is still the most important one. In most cases, high IOP is secondary to trabecular meshwork dysfunction. High IOP leads to compaction of the lamina cribrosa and subsequent damage to retinal ganglion cell axons. Damage to the optic nerve head is evident on funduscopy as posterior bowing of the lamina cribrosa and increased cupping. Currently, the only documented method to slow or halt the progression of this disease is to decrease the IOP; hence, accurate IOP measurement is crucial not only for diagnosis, but also for the management. Due to the dynamic nature and fluctuation of the IOP, a single clinical measurement is not a reliable indicator of diurnal IOP; it requires 24-hour monitoring methods. Technological advances in microelectromechanical systems and microfluidics provide a promising solution for the effective measurement of IOP. This paper provides a broad overview of the upcoming technologies to be used for continuous IOP monitoring.

Muscular Strength Is Associated with Higher Intraocular Pressure in Physically Active Males.

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Vera, Jesús; Jiménez, Raimundo; García-Ramos, Amador; Cárdenas, David

2018-02-01

The positive association between intraocular pressure (IOP) and relative maximum force may have relevance for exercise recommendations when IOP is a concern. The relationship between exercise and IOP has been approached in several studies. However, the influence of muscle function on IOP remains underexplored. This study aimed to determine the relationship between the maximal mechanical capabilities of muscles to generate force, velocity, and power with IOP. Sixty-five physically active males participated in this cross-sectional study. Baseline IOP measures were obtained by rebound tonometry, and participants performed an incremental loading test in the ballistic bench press. Baseline IOP showed a strong positive correlation with relative maximum force (r65 = 0.85, P .05). There is a positive association between greater upper-body power and strength with higher baseline IOP, which might have important implications in the management of ocular health and especially in individuals constantly involved in resistance training programs (e.g., military personnel, weightlifters). The possible protective effect of high fitness level on the acute IOP response to strength exercise needs to be addressed in future studies.

Intraocular pressure control of a novel glaucoma drainage device - in vitro and in vivo studies

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Li-Jun Cui

2017-09-01

Full Text Available AIM: To evaluate the intraocular pressure (IOP control of an artificial trabeculum drainage system (ATDS, a newly designed glaucoma drainage device, and postoperative complications in normal rabbit eyes. METHODS: Pressure drops in air and fluid of 30 ATDS were measured after being connected to a closed manometric system. Twenty of them were then chosen and implanted randomly into the eyes of 20 rabbits. Postoperative slit-lamp, gonioscopic examination and IOP measurements were recorded periodically. Ultrasound biomicroscopy and B-scan ultrasonography were also used to observe the complications. Eyes were enucleated on day 60. RESULTS: Pressure drops of 4.6-9.4 mm Hg were obtained at physiological aqueous flow rates in the tests in vitro. The average postoperative IOP of the experimental eyes (11.6-12.8 mm Hg was lower than the controls significantly (P<0.05 at each time point. Complications of hemorrhage (n=1, cellulosic exudation (two cases and local iris congestion (two cases were observed. The lumina of the devices were devoid of obstructions in all specimens examined and a thin fibrous capsule was found around the endplate. CONCLUSION: ATDS reduce IOP effectively. However, further studies on the structure are needed to reduce complications.

Reference Values for the Ophthalmic Schirmer Tear Test and the Intraocular Pressure in Healthy Chinchillas

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Richards M.

2016-09-01

Full Text Available The objective of this study was to measure the intraocular pressure (IOP and tear production before and after topical anaesthesia in healthy chinchillas (Chinchilla lanigera. Thirteen healthy non-sedated chinchillas (eight males and five females were used in this study. The tear production was measured by the novel endodontic paper point tear test (PPTT using Roeko Colour No. 30 Paper points. Following the PPTT, one drop of 0.4 % oxybuprokainium chloride was added to the eye to anaesthetise the cornea and the IOP was measured using the Tono-Pen Avia®Vet. Excess anaesthetic was removed from the conjunctival fornix using a sterile cotton tipped applicator and the PPTT II was performed. The PPTT I and II were measured in 26 eyes, mean ± standard deviations (SD were 7.98 ± 1.95 mm.min−1, and 9.71 ± 3.52 mm.min−1 respectively. The IOP was measured in 20 eyes, and the mean ± SD was 28.52 ± 12.48 mmHg (35.50 ± 9.31 mmHg in males and 21.53 ± 11.57 mmHg in females. There was no significant difference in the PPTT results between the left and right eyes or between the male and female groups. The males were found to have a significantly higher IOP than females and the PPTT II was significantly greater than the PPTT I. The PPTT test proved to be effective, easy to use, and reliable, causing little apparent discomfort to the chinchillas and could prove to be a much more effective tool than the Schirmer tear test for the evaluation of the tear production in animals with small eyes and/or low aqueous tear production. The mean intraocular pressure proved to be much higher in this population of chinchillas than those previously studied and so further investigation is warranted before a reliable reference range may be produced.

Diagnostic accuracy of the iCare rebound tonometer compared to the Perkins applanation tonometer in assessing intraocular pressure in rural patients.

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Li, Yifan; Carpenter, Christopher R; Nicholson, Kathryn; Milne, William Ken

2015-12-01

Vision health is recognized as a critical unmet need in North America. The ocular morbidity associated with glaucoma results from increased intraocular pressure (IOP) and early detection is crucial for the management of glaucoma. Our objective was to find a diagnostically accurate screening tool for intraocular hypertension that can be used in rural communities. We sought to validate the diagnostic accuracy of the iCare rebound tonometer against the gold standard Perkins applanation tonometer (PAT) in measuring IOP. Patients from two rural communities in Ontario, Canada visiting their optometrists for routine appointments had their IOP measured by a non-contact tonometer (NCT), an iCare rebound tonometer, and a Perkins applanation tonometer (PAT). Values of sensitivity, specificity, and likelihood ratios for a positive and negative result were calculated for the iCare and the NCT. Complete data was collected from 209 patients. Overall, the iCare tonometer had high levels of validity, as compared to the gold standard PAT. The iCare tonometer displayed excellent sensitivity of 98.3% (90-99%, 95% CI) and excellent negative likelihood ratio of 0.024 (0.0088-0.066, 95% CI) which is useful for ruling out intraocular hypertension. The iCare tonometer is a reasonably valid tool for detecting elevated IOP. Its ease of use, simplicity, and accessibility makes it a good screening tool to improve eye health in rural areas.

Advanced pigment dispersion glaucoma secondary to phakic intraocular collamer lens implant

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Clara Ye

2018-06-01

Full Text Available Purpose: We report a case of pigment dispersion glaucoma secondary to uncomplicated phakic intraocular collamer lens (ICL (Visian ICL™, Staar Inc., Monrovia, CA implant that resulted in advanced visual field loss. Observations: A 50-year-old man presented for routine follow-up status post bilateral phakic intraocular collamer lens (ICL placement 8 years earlier. He was incidentally found to have a decline in visual acuity from an anterior subcapsular cataract and elevated intraocular pressure (IOP in the left eye. There were signs of pigment dispersion and no evidence of angle closure. Diffuse optic nerve thinning was consistent with advanced glaucomatous visual field defects. Pigment dispersion was also present in the patient's right eye, but without elevated IOP or visual field defects. The patient was treated with topical glaucoma medications and the phakic ICL in the left eye was removed concurrently with cataract surgery to prevent further visual field loss. Conclusions and importance: Pigment dispersion glaucoma is a serious adverse outcome after phakic ICL implantation and regular post-operative monitoring may prevent advanced visual field loss. Keywords: Phakic intraocular lens, Intraocular collamer lens, Pigment dispersion, Glaucoma

Effect of sildenafil citrate on intraocular pressure and blood pressure in human volunteers.

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Gerometta, Rosana; Alvarez, Lawrence J; Candia, Oscar A

2011-07-01

Anecdotal reports have suggested that the vasodilator, sildenafil citrate, which evokes its effect via a select inhibition of PDE5, has the potential to increase intraocular pressure (IOP) in some individuals. An ocular hypertensive effect by sildenafil was also recently described in a sheep animal model. In contrast, clinical studies have not found a direct association between sildenafil ingestion (commonly consumed as Viagra) and changes in IOP. However, some such studies also reported no effects of sildenafil on systemic blood pressure (BP) at the time of the IOP determination. Given this surprising result, our purpose was to repeat a study in human volunteers in the city of Corrientes, Argentina to corroborate the effects of sildenafil on human IOP and systemic BP. For the present study, 9 healthy volunteers (male and female, 18-74 years old) were selected as subjects after ophthalmic and cardiovascular evaluation indicated that they exhibited normal parameters for their age. In a masked, placebo-controlled study, the subjects ingested 100 mg sildenafil citrate (provided as Vorst from Laboratorios Bernabo, Argentina) in one session, and a placebo on a second separate occasion. IOP was measured with a Goldman applanation tonometer by an ophthalmologist, and BP by a second physician, neither of whom witnessed the tablet ingestion by the volunteers, nor provided with information on the nature of the test compounds. A third individual administered the tablets. The average baseline IOP of this group of 9 was 13.1 ± 0.6 mm Hg. Subsequent to sildenafil ingestion, IOP increased by 26% to 16.5 ± 0.8 mm Hg 60 min later (P < 0.005, as paired data), and returned to control values within 2 h. Both systolic and diastolic BP were significantly reduced by sildenafil ingestion. At the point of maximal systemic hypotension (90 min), the systolic and diastolic pressures declined by 15% and 13%, respectively. No significant changes in IOP or BP were recorded after

Polynomial analysis of ambulatory blood pressure measurements

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Zwinderman, A. H.; Cleophas, T. A.; Cleophas, T. J.; van der Wall, E. E.

2001-01-01

In normotensive subjects blood pressures follow a circadian rhythm. A circadian rhythm in hypertensive patients is less well established, and may be clinically important, particularly with rigorous treatments of daytime blood pressures. Polynomial analysis of ambulatory blood pressure monitoring

Age-related changes in sleep and circadian rhythms: impact on cognitive performance and underlying neuroanatomical networks

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Christina eSchmidt

2012-07-01

Full Text Available Circadian and homeostatic sleep-wake regulatory processes interact in a fine tuned manner to modulate human cognitive performance. Dampening of the circadian alertness signal and attenuated deterioration of psychomotor vigilance in response to elevated sleep pressure with aging change this interaction pattern. As evidenced by neuroimaging studies, both homeostatic sleep pressure and circadian sleep-wake promotion impact on cognition-related cortical and arousal-promoting subcortical brain regions including the thalamus, the anterior hypothalamus and the brainstem locus coeruleus (LC. However, how age- related changes in circadian and homeostatic processes impact on the cerebral activity subtending waking performance remains largely unexplored. Post-mortem studies point to neuronal degeneration in the SCN and age-related modifications to aging in the arousal-promoting LC. Alongside, cortical frontal brain areas are particularly susceptible both to aging and misalignment between circadian and homeostatic processes. In this perspective, we summarise and discuss here the potential neuroanatomical networks underlying age-related changes in circadian and homeostatic modulation of waking performance, ranging from basic arousal to higher order cognitive behaviours.

Circadian Rhythm Neuropeptides in Drosophila: Signals for Normal Circadian Function and Circadian Neurodegenerative Disease.

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He, Qiankun; Wu, Binbin; Price, Jeffrey L; Zhao, Zhangwu

2017-04-21

Circadian rhythm is a ubiquitous phenomenon in many organisms ranging from prokaryotes to eukaryotes. During more than four decades, the intrinsic and exogenous regulations of circadian rhythm have been studied. This review summarizes the core endogenous oscillation in Drosophila and then focuses on the neuropeptides, neurotransmitters and hormones that mediate its outputs and integration in Drosophila and the links between several of these (pigment dispersing factor (PDF) and insulin-like peptides) and neurodegenerative disease. These signaling molecules convey important network connectivity and signaling information for normal circadian function, but PDF and insulin-like peptides can also convey signals that lead to apoptosis, enhanced neurodegeneration and cognitive decline in flies carrying circadian mutations or in a senescent state.

Topical tissue plasminogen activator appears ineffective for the clearance of intraocular fibrin.

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Zwaan, J; Latimer, W B

1998-06-01

To determine the efficacy of topical tissue plasminogen activator (tPA) for the resolution of postoperative or inflammatory intraocular fibrinous exudates. Each treatment consisted of drops of 1 mg/ml tPA given 9 times 5 minutes apart. Records were reviewed and the results at 24 and 48 hours were recorded. Sixty-two patients had a total of 94 treatments. Fibrin exudates following intraocular surgery in 34 patients were treated 44 times. In 6 patients there was a positive result. Fibrin associated with intraocular infection was treated in 9 patients. None showed clear improvement. Nineteen patients had a total of 34 treatments for poorly controlled intraocular pressure (IOP) after glaucoma surgery. Five patients showed adequate control of the IOP, 12 did not change, and 2 had a questionable improvement. Eleven patients had adequate IOP control after additional treatment. Seven required suture lysis, 2 ab interno bleb revision, and 2 YAG capsulotomy or iridotomy to reduce the IOP to an acceptable level. Within the limits of this retrospective study and taking into account that fibrin may resolve spontaneously, it appears that topical tPA drops are not effective for the liquefaction of intraocular fibrin after surgery or in association with intraocular inflammation. They did not improve IOP control after glaucoma surgery.

Appraisal of Bleb Using Trio of Intraocular Pressure, Morphology on Slit Lamp, and Gonioscopy.

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Thatte, Shreya; Rana, Rimpi; Gaur, Neeraj

2016-01-01

The aim of this study was to assess bleb function using Wuerzburg bleb classification score (WBCS) for bleb morphology on slit lamp, intraocular pressure (IOP), and gonioscopy. A total of randomly selected 30 eyes posttrabeculectomy were assessed for bleb function with the trio of bleb morphology, IOP, and gonioscopy. Bleb was assessed using the WBCS of 0-12 on slit lamp, IOP was assessed using applanation tonometry, and visualization of inner ostium and iridectomy were assessed using gonioscopy. Postoperative patients of less than six weeks were excluded from the study. The correlation between WBCS and the duration of trabeculectomy was found to be highly significant ( P value = 0.029). The correlation of IOP with WBCS was also found to be strongly positive ( P = 0.000). IOP was found to be highly associated with peripheral iridectomy ( P = 0.000), internal window ( P = 0.001), and bleb characteristics.

The rectenna design on contact lens for wireless powering of the active intraocular pressure monitoring system.

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Cheng, H W; Jeng, B M; Chen, C Y; Huang, H Y; Chiou, J C; Luo, C H

2013-01-01

This paper proposed a wireless power harvesting system with micro-electro-mechanical-systems (MEMS) fabrication for noninvasive intraocular pressure (IOP) measurement on soft contact lens substructure. The power harvesting IC consists of a loop antenna, an impedance matching network and a rectifier. The proposed IC has been designed and fabricated by CMOS 0.18 um process that operates at the ISM band of 5.8 GHz. The antenna and the power harvesting IC would be bonded together by using flip chip bonding technologies without extra wire interference. The circuit utilized an impedance transformation circuit to boost the input RF signal that improves the circuit performance. The proposed design achieves an RF-to-DC conversion efficiency of 35% at 5.8 GHz.

Influence of bushenhuoxue on primary visual cortex' BDNF damage in rat model of chronic elevated intraocular pressure

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Xiang Li

2013-04-01

Full Text Available AIM: To observe the effect of traditional Chinese medicine(TCMof bushenhuoxue on primary visual cortex(PVCbrain-derived neurotrophic factor(BDNFin rat model of chronic elevated intraocular pressure(EIOP, and explore the mechanism of it initially. METHODS: The rat model of chronic EIOP was established by unilaterally cauterizing 3 episcleral veins, then 30 rats were divided into 3 groups randomly: control group, model group, and treatment group. After given drugs or normal saline for 8 weeks, the rats were put to death. The effect of intraocular pressure(IOP, expression of BDNF and ultrastructure of neuron cell in the PVC was observed. RESULTS: Unilaterally cauterizing episcleral veins increased IOP of the rat model obviously, there was significant difference compared with pre-operation(P<0.01. Semi-quantitative pathological analysis on PVC showed that BDNF of total area in the model group was(82438±2597.39S/μm2,mean optical density was(1155.9±123.14, integrated optical density was(12915±673.28, compared with the control group {total area was(132370±7588.47S/μm2, mean optical density was(5365±379.65, integrated optical density was(35102±2648.5}, there were statistical differences(all P<0.05,there was statistical difference in BDNF of total area between model group and treatment group{(108980±9126.77S/μm2, P<0.05}, significant difference in mean optical density between the model group and treatment group(3220.4±413.67, P<0.05, statistical difference in integrated optical density between the model group and treatment group(23821±3431.68, P<0.05. CONCLUSION: TCM of bushenhuoxue can repair the PVC damage in the rat model of chronic EIOP by enhancing expression of BDNF, improving ultrastructure of neuron cell.

The effects of the modulus of the lens material on intraocular pressure measurement through soft contact lenses.

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Boyraz, S; Güngör, I

2013-09-01

To investigate the effects of the modulus of the lens material on the intraocular pressure measurement using the Tono-Pen XL applanation tonometer through soft contact lenses. Thirty eyes of 15 patients with myopia were evaluated. Intraocular pressure (IOP) measurements were performed using Tono-Pen XL directly over cornea, and subsequently through three soft contact lenses made up of different lens materials. All were -3.00 diopter soft contact lenses: lotrafilcon A with a low water content (24%) and high modulus (1.4 MPa) (CL-I), balafilcon A with a moderate water content (36%) and moderate modulus (1.1 MPa) (CL-II), and vifilcon A with a moderate water content (55%) and low modulus (0.79 MPa) (CL-III). IOP measurements through contact lenses were compared with each other, and with direct corneal measurements. The mean age of the patients (11 males and 4 females) was 26.86±5.62 years. All measurements obtained through CLs were significantly higher than the direct corneal measurements. The measurements through CLs differed by 4.61±0.54 mmHg (P=0,001), 2.9±0.46 mmHg (P=0.001), and 1.94±0.51 mmHg (P=0,003) for CL-I, CL-II and CL-III, respectively. In the paired comparisons of measurements through CLs, all comparisons were significant except the comparison of measurements through CL-II and CL-III (P=0.128). IOP measurements through silicone-hydrogel contact lenses with a high modulus and low water content were higher compared to the other contact lenses. While measuring IOP through CLs, the clinicians should consider the effect of the lens material and the features of the device used.

Associated depression in pseudophakic patients with intraocular lens with and without chromophore

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Mendoza-Mendieta ME

2016-03-01

Full Text Available María Elena Mendoza-Mendieta, Ana Aurora Lorenzo-Mejía Association to Prevent Blindness in Mexico (APEC, Hospital “Dr Luis Sánchez Bulnes”, Mexico City, Mexico Background: With aging, the crystalline lens turns yellowish, which increases the absorption of wavelengths in the blue electromagnetic spectrum, reducing their photoreception in the retina. Since these wavelengths are the main stimulus in the regulation of the circadian rhythm, progressive reduction in their transmission is associated with chronic sleep disturbances and depression in elderly patients. Cataract extraction improves circadian photoreception at any age. However, lenses that block blue waves have 27% to 38% less melatonin suppression than lenses that block only ultraviolet (UV rays. Purpose: To assess the depression symptoms in subjects who have had bilateral phacoemulsification and intraocular lens (IOL implants, one group with yellow chromophore IOLs and the other group with transparent IOLs were compared. Setting: Association to Prevent Blindness in Mexico (APEC, Hospital “Dr Luis Sánchez Bulnes”. Design: This was an observational, cross-sectional, and single-center study. Materials and methods: Twenty-six subjects between 60 and 80 years of age, with a history of bilateral phacoemulsification and placement of the same type of IOL in both eyes from 4 to 12 months prior to the study, who attended the follow-up visits and agreed to participate in this study, and provided signed informed consent were included in the study. They were asked to answer the short version of the 15-item Geriatric Depression Scale. Results: The average age of the study participants was 72.5±5.94 years. The group without chromophore included 46.1% (n=12 of the patients and the group with chromophore included 53.9% (n=14 of the patients (P=0.088. Conclusion: In the group of patients with IOLs that block the passage of blue light, the depression rate was 21.4%, a rate similar to that

Experimental research on intraocular aqueous flow by PIV method.

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Yang, Hongyu; Song, Hongfang; Mei, Xi; Li, Lin; Fu, Xineng; Zhang, Mindi; Liu, Zhicheng

2013-10-21

Aqueous humor flows regularly from posterior chamber to anterior chamber, and this flow much involves intraocular pressure, the eye tissue nutrition and metabolism. To visualize and measure the intraocular flow regular pattern of aqueous humor. Intraocular flow in the vitro eyeball is driven to simulate the physiological aqueous humor flow, and the flow field is measured by Particle Image Velocimetry(PIV). Fluorescent particle solution of a certain concentration was infused into the root of Posterior Chamber(PC) of vitro rabbit eye to simulate the generation of aqueous and was drained out at a certain hydrostatic pressure from the angle of Anterior Chamber(AC) to represent the drainage of aqueous. PIV method was used to record and calculate the flow on the midsagittal plane of the eyeball. Velocity vector distribution in AC has been obtained, and the distribution shows symmetry feature to some extent. Fluorescent particle solution first fills the PC as it is continuously infused, then surges into AC through the pupil, flows upwards toward the central cornea, reflecting and scattering, and eventually converges along the inner cornea surface towards the outflow points at the periphery of the eyeball. Velocity values around the pupillary margin are within the range of 0.008-0.012 m/s, which are close to theoretical values of 0.0133 m/s, under the driving rate of 100 μl/min. Flow field of aqueous humor can be measured by PIV method, which makes it possible to study the aqueous humor dynamics by experimental method. Our study provides a basis for experimental research on aqueous humor flow; further, it possibly helps to diagnose and treat eye diseases as shear force damage of ocular tissues and destructions on corneal endothelial cells from the point of intraocular flow field.

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

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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.

Bilateral Acute Angle-closure after Intraocular Surgery.

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Hoskens, Kirsten; Pinto, Luis Abegão; Vandewalle, Evelien; Verdonk, Nancy; Stalmans, Ingeborg

2014-01-01

We report the case of a 75-year-old woman who developed an acute bilateral angle-closure associated with choroidal effusion a day after an uneventful cataract surgery. The same patient had undergone a similarly uneventful cataract surgery two weeks before, under the same protocol, with no postoperative complication in the other eye. Medical treatment, including the use of oral sulfamide-related drugs (acetazolamide), topical beta-blockers and steroids led to a gradual decrease in intraocular pressure (IOP) and choroidal effusion. Despite initial reports suggesting a link between sulfamide-exposure and these rare forms of angle-closure, our report would suggest a more complex pathophysiology behind this intriguing phenomenon. How to cite this article: Hoskens K, Pinto LA, Vandewalle E, Verdonk N, Stalmans I. Bilateral Acute Angle-closure after Intraocular Surgery. J Curr Glaucoma Pract 2014;8(3):113-114.

Influence of GlideScope assisted endotracheal intubation on intraocular pressure in ophthalmic patients

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Nauman Ahmad

2015-01-01

Full Text Available Background: Traditional Macintoch laryngoscopy is known to cause a rise in intraocular pressure (IOP, tachycardia and hypertension. These changes are not desirable in patients with glaucoma and open globe injury. GlideScope is a video laryngoscope that functions independent of the line of sight, reduces upward lifting forces for glottic exposure and requires less cervical neck movement for intubation, making it less stimulating than Macintosh laryngoscopy. Aim: The aim was to assess the variations in IOP and hemodynamic changes after GlideScope assisted intubation. Materials and Methods: After approval of the local Institutional Research and Ethical Board and informed patient consent, 50 adult American Society of Anesthesiologist I and II patients with normal IOP were enrolled in a prospective, randomized study for ophthalmic surgery requiring tracheal intubation. In all patients, trachea was intubated using either GlideScope or Macintoch laryngoscope. IOP of nonoperated eye, heart rate and blood pressure were measured as baseline, 1 min after induction, 1 min and 5 min after tracheal intubation. Results: IOP was not significantly different between groups before and after anesthetic induction and 5 min after tracheal intubation (P = 0.217, 0.726, and 0.110 respectively. The only significant difference in IOP was at 1 min after intubation (P = 0.041. No significant difference noted between groups in mean arterial pressure (P = 0.899, 0.62, 0.47, 0.82 respectively and heart rate (P = 0.21, 0.72, 0.07, 0.29, respectively at all measurements. Conclusion: GlideScope assisted tracheal intubation shown lesser rise in IOP at 1 min after intubation in comparison to Macintoch laryngoscope, suggesting that GlideScope may be preferable to Macintosh laryngoscope.

Reliable intraocular pressure measurement using automated radio-wave telemetry.

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Paschalis, Eleftherios I; Cade, Fabiano; Melki, Samir; Pasquale, Louis R; Dohlman, Claes H; Ciolino, Joseph B

2014-01-01

To present an autonomous intraocular pressure (IOP) measurement technique using a wireless implantable transducer (WIT) and a motion sensor. The WIT optical aid was implanted within the ciliary sulcus of a normotensive rabbit eye after extracapsular clear lens extraction. An autonomous wireless data system (AWDS) comprising of a WIT and an external antenna aided by a motion sensor provided continuous IOP readings. The sensitivity of the technique was determined by the ability to detect IOP changes resulting from the administration of latanoprost 0.005% or dorzolamide 2%, while the reliability was determined by the agreement between baseline and vehicle (saline) IOP. On average, 12 diurnal and 205 nocturnal IOP measurements were performed with latanoprost, and 26 diurnal and 205 nocturnal measurements with dorzolamide. No difference was found between mean baseline IOP (13.08±2.2 mmHg) and mean vehicle IOP (13.27±2.1 mmHg) (P=0.45), suggesting good measurement reliability. Both antiglaucoma medications caused significant IOP reduction compared to baseline; latanoprost reduced mean IOP by 10% (1.3±3.54 mmHg; P<0.001), and dorzolamide by 5% (0.62±2.22 mmHg; P<0.001). Use of latanoprost resulted in an overall twofold higher IOP reduction compared to dorzolamide (P<0.001). Repeatability was ±1.8 mmHg, assessed by the variability of consecutive IOP measurements performed in a short period of time (≤1 minute), during which the IOP is not expected to change. IOP measurements in conscious rabbits obtained without the need for human interactions using the AWDS are feasible and provide reproducible results.

Reliable intraocular pressure measurement using automated radio-wave telemetry

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Paschalis, Eleftherios I; Cade, Fabiano; Melki, Samir; Pasquale, Louis R; Dohlman, Claes H; Ciolino, Joseph B

2014-01-01

Purpose To present an autonomous intraocular pressure (IOP) measurement technique using a wireless implantable transducer (WIT) and a motion sensor. Methods The WIT optical aid was implanted within the ciliary sulcus of a normotensive rabbit eye after extracapsular clear lens extraction. An autonomous wireless data system (AWDS) comprising of a WIT and an external antenna aided by a motion sensor provided continuous IOP readings. The sensitivity of the technique was determined by the ability to detect IOP changes resulting from the administration of latanoprost 0.005% or dorzolamide 2%, while the reliability was determined by the agreement between baseline and vehicle (saline) IOP. Results On average, 12 diurnal and 205 nocturnal IOP measurements were performed with latanoprost, and 26 diurnal and 205 nocturnal measurements with dorzolamide. No difference was found between mean baseline IOP (13.08±2.2 mmHg) and mean vehicle IOP (13.27±2.1 mmHg) (P=0.45), suggesting good measurement reliability. Both antiglaucoma medications caused significant IOP reduction compared to baseline; latanoprost reduced mean IOP by 10% (1.3±3.54 mmHg; P<0.001), and dorzolamide by 5% (0.62±2.22 mmHg; P<0.001). Use of latanoprost resulted in an overall twofold higher IOP reduction compared to dorzolamide (P<0.001). Repeatability was ±1.8 mmHg, assessed by the variability of consecutive IOP measurements performed in a short period of time (≤1 minute), during which the IOP is not expected to change. Conclusion IOP measurements in conscious rabbits obtained without the need for human interactions using the AWDS are feasible and provide reproducible results. PMID:24531415

Fitness Level Modulates Intraocular Pressure Responses to Strength Exercises.

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Vera, Jesús; Jiménez, Raimundo; Redondo, Beatríz; Cárdenas, David; García-Ramos, Amador

2018-06-01

Purpose/Aim: The execution of strength exercises has demonstrated to increase the intraocular pressure (IOP) levels, and it may have a negative impact on the ocular health. We aimed to explore the influence of fitness level on the acute IOP response to strength exercises performed under different loading conditions, as well as to test whether the IOP responses differ between the bench press and jump squat when performed against the same relative loads. Forty military personnel males were divided in two subgroups (20 high-fit and 20 low-fit) based on their relative to body mass one-repetition maximum (1-RM). Participants performed an incremental loading test in the bench press and jump squat exercises, and IOP was assessed before and after each repetition by rebound tonometry. IOP increased immediately after executing both exercises (p e., high-fit and low-fit) and in both exercises (R 2 range: 0.81-1.00). Higher fitness level attenuated the IOP rise produced by both exercises (p < 0.01 in both cases). The bench press induced higher IOP increments than the jump squat for both groups at relative loads of ~50%1-RM and ~60%1-RM (p < 0.01 in all cases). These data indicate that IOP increases as a consequence of performing strength exercises, being the increment accentuated with the increase of the load and in the bench press compared to the jump squat exercise. Of special importance would be that the IOP responses were significantly reduced in high-fit individuals. These findings should be addressed in glaucoma patients.

Evaluation of the intraocular pressure measured with the ocular response analyzer.

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Ogbuehi, Kelechi C; Almubrad, Turki M

2010-07-01

Comparison of the magnitude and repeatability of the intraocular pressure (IOP) measured with the Ocular Response Analyzer (ORA) to that measured with the Goldmann tonometer. Two sets of IOP measurements were made, for 89 eyes of eighty-nine subjects, approximately 1-week apart. Goldmann tonometry was performed subsequent to non-contact tonometry, in which the order of measurement was randomized between the ORA and the Topcon CT80 non-contact tonometer (CT80). Each method was assessed twice for intrasession repeatability. The limits of agreement between each non-contact pressure and that measured with the Goldmann tonometer were assessed once per session. The level of statistical significance was 0.05. The mean differences between the ORA-corneal compensated, Goldmann-correlated, and CT80-IOP (ORA-IOPcc; ORA-IOPg and CT80-IOP) versus the Goldmann IOP were -0.3 +/- 2.7 mmHg (mean +/- SD), -0.3 +/- 2.2 mmHg and -0.3 +/- 2.1 mmHg, respectively for session 1 and 0.3 +/- 3.0 mmHg, 0.2 +/- 2.2 mmHg, and -0.5 +/- 2.2 mmHg, respectively, for session 2. The repeatability coefficients were +/- 5.3 mmHg, +/- 4.2 mmHg, +/- 2.5 mmHg, and +/- 1.9 mmHg, respectively for ORA-IOPcc, ORA-IOPg, CT80-IOP, and Goldmann IOP in session 1 and +/- 3.8 mmHg, +/- 3.6 mmHg, +/- 1.6 mmHg, and +/- 1.9 mmHg, respectively for session 2. The repeatability indices for the ORA were poorer than those with the Goldmann tonometer and the CT80 in both sessions. However, the average IOP measured with the ORA did not vary significantly from those measured with the other two tonometers in either session. The ORA provides valid, repeatable measures of IOP.

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

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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.

Diurnal Alterations of Refraction, Anterior Segment Biometrics, and Intraocular Pressure in Long-Time Dehydration due to Religious Fasting.

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Baser, Gonen; Cengiz, Hakan; Uyar, Murat; Seker Un, Emine

2016-01-01

To investigate the effects of dehydration due to fasting on diurnal changes of intraocular pressure, anterior segment biometrics, and refraction. The intraocular pressures, anterior segment biometrics (axial length: AL; Central corneal thickness: CCT; Lens thickness: LT; Anterior chamber depth: ACD), and refractive measurements of 30 eyes of 15 fasting healthy male volunteers were recorded at 8:00 in the morning and 17:00 in the evening in the Ramadan of 2013 and two months later. The results were compared and the statistical analyses were performed using the Rstudio software version 0.98.501. The variables were investigated using visual (histograms, probability plots) and analytical methods (Kolmogorov-Smirnov/Shapiro-Wilk test) to determine whether or not they were normally distributed. The refractive values remained stable in the fasting as well as in the control period (p = 0.384). The axial length measured slightly shorter in the fasting period (p = 0.001). The corneal thickness presented a diurnal variation, in which the cornea measured thinner in the evening. The difference between the fasting and control period was not statistically significant (p = 0.359). The major differences were observed in the anterior chamber depth and IOP. The ACD was shallower in the evening during the fasting period, where it was deeper in the control period. The diurnal IOP difference was greater in the fasting period than the control period. Both were statistically significant (p = 0.001). The LT remained unchanged in both periods. The major difference was shown in the anterior chamber shallowing in the evening hours and IOP. Our study contributes the hypothesis that the posterior segment of the eye is more responsible for the axial length alterations and normovolemia has a more dominant influence on diurnal IOP changes.

Respiratory complications associated with ketamine anesthesia for ophthalmic procedures following intraocular pressure measurement in children

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Lei Wu

2014-01-01

Full Text Available Background: We compared respiratory complications (RCs in children who received intramuscular (IM versus intravenous (IV or no ketamine for intraocular pressure (IOP measurement to test our observation that IM ketamine is associated with higher incidence of RCs. Materials and Methods: We analyzed 149 eye examinations under anesthesia with ketamine in 27 patients and 263 non-ketamine examinations under anesthesia in 81 patients using a mixed effects logistic regression model. Results: IM ketamine was strongly associated with increased odds of RCs compared to no ketamine (odds ratio (OR: 20.23, P < 0.0001 and to IV ketamine (OR: 6.78, P = 0.02, as were higher American Society of Anesthesiologists (ASA classification (OR: 2.60, P = 0.04, and the use of volatile agents (OR: 3.32, P = 0.02. Conclusion: Further studies should be conducted to confirm our observation of increased RCs with IM ketamine.

Intraocular pressure elevation precedes a phagocytosis decline in a model of pigmentary glaucoma [version 2; referees: 2 approved

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Yalong Dang

2018-04-01

Full Text Available Background: Outflow regulation and phagocytosis are key functions of the trabecular meshwork (TM, but it is not clear how the two are related in secondary open angle glaucomas characterized by an increased particle load. We hypothesized that diminished TM phagocytosis is not the primary cause of early ocular hypertension and recreated pigment dispersion in a porcine ex vivo model. Methods: Sixteen porcine anterior chamber cultures received a continuous infusion of pigment granules (Pg, while 16 additional anterior chambers served as controls (C. Pressure transducers recorded the intraocular pressure (IOP. The phagocytic capacity of the trabecular meshwork was determined by fluorescent microspheres. Results: The baseline IOPs in Pg and C were similar (P=0.82. A significant IOP elevation occurred in Pg at 48, 120, and 180 hours (all P0.05. Conclusions: In this porcine model of pigmentary glaucoma, an IOP elevation occurs much earlier than when phagocytosis fails, suggesting that two separate mechanisms might be at work.

Effect of phacoemulsification on intraocular pressure in patients with primary open angle glaucoma and pseudoexfoliation glaucoma

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Jesus Jimenez-Roman

2017-09-01

Full Text Available AIM: To compare the effect of phacoemulsification on intraocular pressure (IOP in patients with primary open angle glaucoma (POAG and pseudoexfoliation glaucoma (PXG. METHODS: A retrospective comparative case series conducted at the Glaucoma Department at the Association to Prevent Blindness in Mexico. The study enrolled consecutive patients having phacoemulsification with intraocular lens (IOL implantation and a diagnosis of POAG or PXG. Data about IOP values and number of glaucoma medications used was collected at baseline, 1, 3, 6 and 12mo postoperatively. RESULTS: The study enrolled 88 patients (88 eyes. After phacoemulsification, there was a statistically significant reduction in IOP values and glaucoma medications use compared to baseline in both POAG and PXG patients (P<0.001. In the POAG group, a 20% decrease in IOP values was evidenced, and a 56.5% reduction in the number of medications used at the one-year follow-up. The PXG group showed a 20.39%, and a 34.46% decrease in IOP and number of medications used, respectively. A significant difference in the mean ΔIOP (postoperative changes in IOP was evidenced between groups (P=0.005. The reduction of the postsurgical IOP mean values in both groups, the POAG group showed a greater reduction in IOP values compared to the PXG group. CONCLUSION: In both types of glaucoma, phacoemulsification cataract surgery can result in a significant IOP reduction (20% over a 12mo follow-up period. The number of medications used is also significantly reduced up to 12mo after surgery, especially in the PXG group.

The effect of hydrogel and silicone hydrogel contact lenses on the measurement of intraocular pressure with rebound tonometry.

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Zeri, Fabrizio; Calcatelli, Paolo; Donini, Bernardo; Lupelli, Luigi; Zarrilli, Luciana; Swann, Peter G

2011-12-01

To assess the accuracy of intraocular pressure (IOP) measurements using rebound tonometry over disposable hydrogel (etafilcon A) and silicone hydrogel (senofilcon A) contact lenses (CLs) of different powers. The experimental group comprised 36 subjects (19 male, 17 female). IOP measurements were undertaken on the subject's right eyes in random order using a rebound tonometer (ICare). The CLs had powers of +2.00D, -2.00D and -6.00D. Six measurements were taken over each contact lens and also before and after the CLs had been worn. A good correlation was found between IOP measurements with and without CLs (all r≥0.80; pContact Lens Association. Published by Elsevier Ltd. All rights reserved.

Intraocular (Eye) Melanoma—Health Professional Version

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Intraocular (uveal) melanoma of the uveal tract (iris, ciliary body, and choroid), though rare, is the most common primary intraocular malignancy in adults. Find evidence-based information on intraocular melanoma treatment.

Common genetic determinants of intraocular pressure and primary open-angle glaucoma.

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Leonieke M E van Koolwijk

Full Text Available Intraocular pressure (IOP is a highly heritable risk factor for primary open-angle glaucoma and is the only target for current glaucoma therapy. The genetic factors which determine IOP are largely unknown. We performed a genome-wide association study for IOP in 11,972 participants from 4 independent population-based studies in The Netherlands. We replicated our findings in 7,482 participants from 4 additional cohorts from the UK, Australia, Canada, and the Wellcome Trust Case-Control Consortium 2/Blue Mountains Eye Study. IOP was significantly associated with rs11656696, located in GAS7 at 17p13.1 (p=1.4×10(-8, and with rs7555523, located in TMCO1 at 1q24.1 (p=1.6×10(-8. In a meta-analysis of 4 case-control studies (total N = 1,432 glaucoma cases, both variants also showed evidence for association with glaucoma (p=2.4×10(-2 for rs11656696 and p=9.1×10(-4 for rs7555523. GAS7 and TMCO1 are highly expressed in the ciliary body and trabecular meshwork as well as in the lamina cribrosa, optic nerve, and retina. Both genes functionally interact with known glaucoma disease genes. These data suggest that we have identified two clinically relevant genes involved in IOP regulation.

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

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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.

Use of subconjunctival injections of 5-fluorouracil to rescue and prolong intraocular pressure reduction for a failing Ahmed glaucoma implant.

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Kaplowitz, Kevin; Khodadadeh, Sarah; Wang, Samantha; Lee, Daniel; Tsai, James C

2017-06-01

5-Fluorouracil (5-FU) has been well described for a failing trabeculectomy bleb, but not for aqueous shunts. We sought to determine whether subconjunctival 5-FU prolongs the intraocular pressure (IOP) efficacy of Ahmed shunts. We included all patients with Ahmed FP-7 implantation by one surgeon at Yale University. Patients with  21 on >2 medications. Five-milligram (0.1 cc) injections were made over the plate. The control group consisted of Ahmed FP-7 patients without injections. The main outcome measure was IOP. Secondary outcome was success (IOP Ahmed shunts. Outcomes between eyes receiving injections and controls were statistically similar.

Effect of changes in PCO2 and body positions on intraocular pressure during general anaesthesia.

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Hvidberg, A; Kessing, S V; Fernandes, A

1981-08-01

Elevated arterial carbon dioxide tension, induced by the administration of CO2 via the respiratory air or by hypoventilation, entailed a gradual increase in the IOP in patients without eye diseases under general anaesthesia. A sudden cessation of CO2 administration or hyperventilation caused such a rapid, simultaneous fall in IOP to values below the initial level that the pressure variations must be of vascular nature, presumably related to changes in choroidal blood volume. The above-mentioned procedures always cause a change in the central venous pressure (CVP) simultaneously with the IOP changes. Alterations of the CVP induced by hydrostatic factors in postural changes, placing the head 15 degrees above or below the horizontal level while keeping the PaCO2 constant, caused IOP changes of the same configuration and magnitude as described above. It is concluded, therefore, that presumably the CO2-conditioned IOP changes are due predominantly to changes in central venous pressure, being one link in a CO2-conditioned action upon the general circulation, entailing passive secondary changes in the choroidal venous blood volume and thereby an influence upon the IOP. On the basis of the present results it appears rational to recommend hyperventilation to keep the PaCO2 between 25 and 30 mm and a 15 degree anti-Trendelenburg position in operations on the eye under general anaesthesia, since both procedures afford a low central venous pressure and consequently a low pressure in the posterior segment of the eye, with its attendant advantages as regards vitreous complications and the insertion of intraocular lenses. Owing to the risk of an unacceptable fall in BP in the combined procedure, a frequent checking of the BP is needed.

Sex and ancestry determine the free-running circadian period.

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Eastman, Charmane I; Tomaka, Victoria A; Crowley, Stephanie J

2017-10-01

The endogenous, free-running circadian period (τ) determines the phase relationship that an organism assumes when entrained to the 24-h day. We found a shorter circadian period in African Americans compared to non-Hispanic European Americans (24.07 versus 24.33 h). We speculate that a short circadian period, closer to 24 h, was advantageous to humans living around the equator, but when humans migrated North out of Africa, where the photoperiod changes with seasons, natural selection favoured people with longer circadian periods. Recently, in evolutionary terms, immigrants came from Europe and Africa to America ('the New World'). The Europeans were descendents of people who had lived in Europe for thousands of years with changing photoperiods (and presumably longer periods), whereas Africans had ancestors who had always lived around the equator (with shorter periods). It may have been advantageous to have a longer circadian period while living in Europe early in the evolution of humans. In our modern world, however, it is better to have a shorter period, because it helps make our circadian rhythms earlier, which is adaptive in our early-bird-dominated society. European American women had a shorter circadian period than men (24.24 versus 24.41), but there was no sex difference in African Americans (24.07 for both men and women). We speculate that selection pressures in Europe made men develop a slightly longer period than women to help them track dawn which could be useful for hunters, but less important for women as gatherers. © 2017 The Authors. Journal of Sleep Research published by John Wiley & Sons Ltd on behalf of European Sleep Research Society.

Three Toxic Heavy Metals in Open-Angle Glaucoma with Low-Teen and High-Teen Intraocular Pressure: A Cross-Sectional Study from South Korea

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Lee, Si Hyung; Kang, Eun Min; Kim, Gyu Ah; Kwak, Seung Woo; Kim, Joon Mo; Bae, Hyoung Won; Seong, Gong Je; Kim, Chan Yun

2016-01-01

Background To investigate the association between heavy metal levels and open-angle glaucoma (OAG) with low- and high-teen baseline intraocular pressure (IOP) using a population-based study design. Methods This cross-sectional study included 5,198 participants older than 19 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2012 and had blood heavy metal levels available. The OAG with normal baseline IOP (IOP ? 21 mmHg) subjects...

Characteristic of intraocular pressure distribution in population of 1115 Tibetan aged 40 years old or more

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Gui-Qin Wang

2014-07-01

Full Text Available AIM: To analyze of characteristic of intraocular pressure(IOPdistribution in population of 1115 Tibetan aged 40 years old or more and its correlative factors such as ages, gender and anterior chamber depth in Tibetan plateau area. METHODS: A total of 1115 Tibetan permanent residents aged 40 years or older from the towns and villages of Qushui County were divided into four age groups: ≥40～RESULTS: The mean IOP of 1115(2145 eyesTibetan permanent residents aged 40 years or older was 12.9±2.7mmHg, 13.2±2.8mmHg in men and 12.7±2.5mmHg in women. The results showed that the participants with anterior chamber depth of 1/2 corneal thickness had 68.8% in 1115(2128 eyesTibetan permanent residents and anterior chamber depth decreases significantly with age(PPCONCLUSION: The mean IOP of plateau subjects was significantly lower from that of plain subjects by approximately 3 mmHg. There are lower pressure, deeper anterior chamber depth in this population of 1115 Tibetan permanent residents. The more attention should be paid to screening for glaucoma in high plateau.

Novel Gonioscopy Score and Predictive Factors for Intraocular Pressure Lowering After Phacoemulsification.

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Perez, Claudio I; Chansangpetch, Sunee; Feinstein, Max; Mora, Marta; Nguyen, Anwell; Badr, Mai; Masis, Marisse; Lin, Shan C

2018-05-04

To evaluate a novel gonioscopy score as a potential predictor for intraocular pressure (IOP) reduction after cataract surgery. Prospective study that included consecutive patients with or without glaucoma, either with open or narrow angles but without peripheral anterior synechiae, who underwent phacoemulsification. Eyes with intraoperative complications and secondary glaucoma were excluded. A preoperative gonioscopy score was created, summing the Shaffer gonioscopy grading in 4 quadrants (range 0-16). To determine variables associated with IOP change at 6 months, univariate and multivariate linear mixed-effects regression analysis was performed adjusting for age, sex, and preoperative IOP. 188 eyes from 137 patients were enrolled. The mean age of the patients was 75.0 (±8.5) years and the average preoperative IOP was 15.6 (±3.6) mm Hg with 0.7 (range 0-4) glaucoma medications. The mean IOP reduction after phaco was 3.0 (±2.6) mm Hg at postoperative month 6. After multivariate analysis, preop IOP (β=0.49 [0.41 - 0.58] Pgonioscopy score (β=-0.17 [-0.24 - -0.09] Pgonioscopy score and IOP/ACD ratio. The IOP/ACD ratio and gonioscopy score can be easy parameters to obtain and may help clinicians to estimate the IOP reduction after phaco.

Intraocular Pressure Induced Retinal Changes Identified Using Synchrotron Infrared Microscopy.

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Hsin-Hui Shen

Full Text Available Infrared (IR spectroscopy has been used to quantify chemical and structural characteristics of a wide range of materials including biological tissues. In this study, we examined spatial changes in the chemical characteristics of rat retina in response to intraocular pressure (IOP elevation using synchrotron infrared microscopy (SIRM, a non-destructive imaging approach. IOP elevation was induced by placing a suture around the eye of anaesthetised rats. Retinal sections were collected onto transparent CaF2 slides 10 days following IOP elevation. Using combined SIRM spectra and chemical mapping approaches it was possible to quantify IOP induced changes in protein conformation and chemical distribution in various layers of the rat retina. We showed that 10 days following IOP elevation there was an increase in lipid and protein levels in the inner nuclear layer (INL and ganglion cell layer (GCL. IOP elevation also resulted in an increase in nucleic acids in the INL. Analysis of SIRM spectra revealed a shift in amide peaks to lower vibrational frequencies with a more prominent second shoulder, which is consistent with the presence of cell death in specific layers of the retina. These changes were more substantial in the INL and GCL layers compared with those occurring in the outer nuclear layer. These outcomes demonstrate the utility of SIRM to quantify the effect of IOP elevation on specific layers of the retina. Thus SIRM may be a useful tool for the study of localised tissue changes in glaucoma and other eye diseases.

Effect of benzalkonium chloride?free travoprost on intraocular pressure and ocular surface symptoms in patients with glaucoma previously on latanoprost: an open-label study

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Lopes, Joao F.; Hubatsch, Douglas A.; Amaris, Patricia

2015-01-01

Background Prostaglandin analogs reduce intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension; however, these medications may affect the ocular surface and elicit ocular discomfort when preserved with benzalkonium chloride (BAK). Methods This was an open-label, single-arm study conducted in Latin America from February 2012 to May 2013. Patients with open-angle glaucoma or ocular hypertension who were intolerant of latanoprost 0.005?% were transitioned to recei...

Hourly awakening vs continuous contact lens sensor measurements of 24-hour intraocular pressure: effect on sleep macrostructure and intraocular pressure rhythm.

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Aptel, Florent; Tamisier, Renaud; Pépin, Jean-Louis; Mottet, Benjamin; Hubanova, Ralitsa; Romanet, Jean-Paul; Chiquet, Christophe

2014-10-01

All studies of 24-hour intraocular pressure (IOP) rhythm conducted to date have used repeated IOP measurements requiring nocturnal awakenings, potentially disturbing sleep macrostructure. To evaluate the effects on sleep architecture and IOP rhythm of hourly awakening vs a contact lens sensor (CLS) to continuously monitor IOP without awakening. Cross-sectional study at a referral center of chronobiology among 12 young healthy volunteers, with a mean (SD) age of 22.3 (2.3) years. Volunteers underwent two 24-hour IOP measurement sessions during a 2-month period. The eye order and session order were randomized. During one session, the IOP of the first eye was continuously monitored using a CLS, and the IOP of the fellow eye was measured hourly using a portable noncontact tonometer (session with nocturnal hourly awakening). During the other session, the IOP of the first eye was continuously monitored using a CLS, and the IOP of the fellow eye was not measured (session without nocturnal awakening). Overnight polysomnography was performed during the 2 sessions. A nonlinear least squares, dual-harmonic regression analysis was used to model the 24-hour IOP rhythm from the CLS data. Comparisons of acrophase, bathyphase, amplitude, and the midline estimating statistic of rhythm were used to evaluate the effect of hourly awakening on IOP rhythm. To evaluate the effects of hourly awakening on sleep architecture, comparisons of sleep structure were used, including total sleep period, rapid eye movement, wake after sleep onset, absolute and relative total sleep time, and non-rapid eye movement sleep (N1, N2, and N3). A 24-hour IOP rhythm was found in all individuals for the sessions with and without awakening (P  .30). Hourly awakening during noncontact tonometer IOP measurements did not seem to alter the mean variables of the 24-hour IOP pattern evaluated using CLS, including signal, maximum signal, minimum signal, acrophase, and bathyphase (P > .15). The 24-hour IOP

The effects of gender on circadian rhythm of human physiological indexes in high temperature environment

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Zheng, G. Z.; Li, K.; Bu, W. T.; Lu, Y. Z.; Wang, Y. J.

2018-03-01

In the context of frequent high temperature weather in recent years, peoples’ physical health is seriously threatened by the indoor high temperature. The physiological activities of human body show a certain changes of circadian rhythm. In this paper, the circadian rhythms of the physiological indexes in indoor high temperature environment were quantified and compared between the male subjects and female subjects. Ten subjects (five males and five females) were selected. The temperature conditions were set at 28°C, 32°C, 36°C and 38°C, respectively. The blood pressure, heart rate, rectal temperature, eardrum temperature, forehead temperature and mean skin temperature were measured for 24 hours continuously. The medians, amplitudes and acrophases of the circadian rhythms were obtained by the cosinor analysis method. Then the effects of gender on the circadian rhythm of the human body in high temperature environment were analyzed. The results indicate that, compared with the female subjects, the male medians of the systolic pressure and diastolic pressure were higher, and the male medians of heart rate and rectal temperature were lower, however, no significant differences were found between eardrum temperature, forehead temperature and mean skin temperature. This study can provide scientific basis for the health protection of the indoor relevant personnel.

Long-term intraocular pressure after combined trabeculotomy-trabeculectomy in glaucoma associated with Sturge-Weber syndrome.

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Sood, Devindra; Rathore, Aanchal; Sood, Ishaana; Kumar, Dinesh; Sood, Narender N

2018-03-01

Vision loss in Sturge-Weber syndrome (SWS), a rare congenital disorder, is primarily due to glaucoma. We reviewed the data of all consecutive SWS-associated glaucoma cases in patients who had undergone combined trabeculotomy-trabeculectomy (CTT) at a tertiary glaucoma facility between January 1993 and December 2015. We analyzed the preoperative and postoperative intraocular pressure (IOP), corneal clarity, visual acuity, success rate, need for repeat surgery, and number of topical antiglaucoma medications needed at last follow-up. Twenty-six eyes of 20 patients with SWS (surgical age 0.7-96 months; mean 18.64 ± 29.74 months) had undergone primary CTT. The mean preoperative IOP was 32.76 ± 7.86 mm Hg (range 22-54 mm Hg) with medication (mean 3.11 ± 1.17; range 1-5). At the last follow-up (61-288 months); mean SD 134.73 ± 67.77 months), two eyes had IOP glaucoma in children. Long-term visual and surgical outcomes are encouraging.

The measurement of intraocular pressure over positive soft contact lenses by rebound tonometry.

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Zeri, Fabrizio; De Cusatis, Mario; Lupelli, Luigi; Swann, Peter Graham

2016-01-01

To investigate if the accuracy of intraocular pressure (IOP) measurements using rebound tonometry over disposable hydrogel (etafilcon A) contact lenses (CL) is affected by the positive power of the CLs. The experimental group comprised 26 subjects, (8 male, 18 female). IOP measurements were undertaken on the subjects' right eyes in random order using a Rebound Tonometer (ICare). The CLs had powers of +2.00D and +6.00D. Measurements were taken over each contact lens and also before and after the CLs had been worn. The IOP measure obtained with both CLs was significantly lower compared to the value without CLs (t test; p<0.001) but no significant difference was found between the two powers of CLs. Rebound tonometry over positive hydrogel CLs leads to a certain degree of IOP underestimation. This result did not change for the two positive lenses used in the experiment, despite their large difference in power and therefore in lens thickness. Optometrists should bear this in mind when measuring IOP with the rebound tonometer over plus power contact lenses. Copyright © 2016 The Authors. Published by Elsevier Espana.. All rights reserved.

Effects of corn silk aqueous extract on intraocular pressure of ocular hypertensive human subjects

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G.O. George

2013-01-01

Full Text Available Stigma/style of Zea mays L (Corn silk has been documented to have hypotensive effect on blood pressure and to relieve oedema. However we are not aware of any literature on its hypotensive effect on intraocular pressure (IOP of humans or animals. We studied the effects of water only, masked doses of corn silk aqueous extract (60 mg/kg, 130 mg/kg, 192.5 mg/kg and 260 mg/kg body weight on the IOP and blood pressure (BP of twenty normotensives and twenty ocular hypertensive subjects. Also we compared the effects of the varied doses of corn silk aqueous extract (CSAE with masked doses (5 mg/kg and 10 mg/kg body weight of acetazolamide on IOP of ocular hypertensive subjects only. The results showed that the last three doses of CSAE lowered IOP and BP significantly (p<0.001 within eight hours of administration. The peak effect on IOP was observed after four hours while the peak effect on BP was observed after three hours of administration in the normotensives and ocular hypertensive subjects likewise the hypotensive effect was dose-dependent. The results also showed that 130 mg/kg body weight of CSAE produced the same hypotensive effect on IOP of ocular hypertensive subjects as 5 mg/kg body weight of acetazolamide. Therefore CSAE may have some IOP lowering effects that require further investigation in the management of ocular hypertension. (S Afr Optom 2013 72(3 133-143

Red-free light for measurement of intraocular pressure using Goldmann applanation tonometer without fluorescein.

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Ghoneim, Ehab M

2014-01-01

To evaluate the use of red-free light for the measurement of intraocular pressure (IOP) using a Goldmann applanation tonometer without fluorescein. This cross-sectional study was carried out on 500 eyes in 250 patients attending the Ophthalmology Outpatient Clinic at Suez Canal University Hospital. The IOP was measured using a Goldmann applanation tonometer mounted on a Haag-Streit slit-lamp. The measurements were performed first using red-free light without fluorescein. Then the measurements were repeated with cobalt blue light and topical fluorescein on the same eyes. The mean IOP was 15.23 ± 3.3 (SD) mm Hg using the red-free light without fluorescein, whereas it was 15.78 ± 3.7 (SD) mm Hg when measured using cobalt blue light after the application of fluorescein to the conjunctival sac. This difference was not statistically significant. Measurement of IOP with a Goldmann applanationtonometer with red-free light and without the use of fluorescein is simple, saves time, and gives an accurate IOP measurement relative to the traditional measurement technique with cobalt blue light and topical fluorescein.

Intraocular pressure following 18 hours of systemic dehydration in ocular normotensive healthy subjects

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Faustina K. Idu

2015-07-01

Full Text Available Aim: To investigate the effect of dehydration on intraocular pressure (IOP. Subjects: The study population comprised 50 subjects (27 men and 23 women with a mean age of 42.84 ± 2.64 years. Method: The subjects dehydrated for 18 hours. IOP was assessed in both eyes using the Perkins handheld applanation tonometer. Baseline measurement of IOP was taken before the subjects dehydrated for 18 hours and repeated after dehydration. Blood samples were taken before and after dehydration for the determination of plasma osmolality and plasma antidiuretic hormone (ADH concentrations. Results: A statistically significant (p < 0.001 reduction in the mean weight of subjects occurred after dehydration. There was a significant reduction in IOP from 16.68 mmHg ± 0.32 mmHg to 13.08 mmHg ± 0.31 mmHg after dehydration (p < 0.001. Mean plasma osmolality showed a statistically significant increase (p < 0.05 from baseline of 290.02 mOsmol/kg ± 1.25 mOsmol/kg to 294.96 mOsmol/kg ± 1.33 mOsmol/kg after dehydration. There was also a significant increase (p < 0.05 in mean plasma ADH concentration from 5.36 pg/mL ± 0.21 pg/mL to 6.40 pg/mL ± 0.20 pg/mL after dehydration. There were no significant differences in both systolic and diastolic blood pressures before and after dehydration. Conclusion: Dehydration decreases IOP in healthy humans; this decrease probably results from an increase in plasma osmolality and plasma ADH concentrations.

Effects of timolol maleate, levobunolol and apraclonidine on intraocular pressure, pupil size, blood pressure and heart rate in beagles

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I.R.M. Padua

2016-06-01

Full Text Available ABSTRACT The aim of this study was to evaluate changes in intraocular pressure (IOP, pupil size (PS, blood pressure (BP, heart rate (HR, and ECG variables (Pms wave PmV, PR interval, QRS complex, RMV wave and QT intervals over time during the instillation of 0.5% timolol, 0.5% levobunolol and 0.5% apraclonidine in clinically normal dogs. Ten adult beagles were used. Baseline values were measured at 8a.m., 2p.m. and 8p.m., for three consecutive days. A waiting period of 10 days between the administrations of each drug was established. For 15 consecutive days, the drug being tested was instilled in one eye of each dog twice a day (7a.m. and 7p.m.. The parameters were evaluated at the aforementioned times on days 3, 6, 9, 12 and 15. Data were statistically compared using the Bonferroni test and one-way repeated measures analysis of variance (P<0.05. The Pearson test was used to evaluate any correlation between QT interval, HR and BP. The tested drugs did not find a decrease in IOP. A significant decreased in PS was observed in almost all dogs following levobunolol administration, relative to the control eye. A significant decrease in HR was observed on day 3 following levobunolol treatment, while apraclonidine induced an increase on day 15. Blood pressure was reduced in all measurement time points following apraclonidine treatment. A negative correlation between QT interval and HR was only observed in dogs treated with timolol. In conclusion, levobunolol was the only drug that induced significant alterations in PS. Apraclonidine was the only drug that induced systemic hypotension. Timolol was the only drug to that induced a negative correlation between QT and HR.

The 24-hour intraocular pressure control by tafluprost/timolol fixed combination after switching from the concomitant use of tafluprost and timolol gel-forming solution, in patients with primary open-angle glaucoma

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Nakamoto K

2018-02-01

habitual positions were lower for the TAF/TIM-FC phase than for the concomitant phase. Conclusion: TAF/TIM-FC showed a stable 24-hour IOP-lowering effect and was equally or more effective than the concomitant use of tafluprost and timolol gel, both when sitting and when in habitual positions. Keywords: intraocular pressure, tafluprost, circadian IOP, 24-hour IOP, timolol gel

System for Rapid, Precise Modulation of Intraocular Pressure, toward Minimally-Invasive In Vivo Measurement of Intracranial Pressure.

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Max A Stockslager

Full Text Available Pathologic changes in intracranial pressure (ICP are commonly observed in a variety of medical conditions, including traumatic brain injury, stroke, brain tumors, and glaucoma. However, current ICP measurement techniques are invasive, requiring a lumbar puncture or surgical insertion of a cannula into the cerebrospinal fluid (CSF-filled ventricles of the brain. A potential alternative approach to ICP measurement leverages the unique anatomy of the central retinal vein, which is exposed to both intraocular pressure (IOP and ICP as it travels inside the eye and through the optic nerve; manipulating IOP while observing changes in the natural pulsations of the central retinal vein could potentially provide an accurate, indirect measure of ICP. As a step toward implementing this technique, we describe the design, fabrication, and characterization of a system that is capable of manipulating IOP in vivo with <0.1 mmHg resolution and settling times less than 2 seconds. In vitro tests were carried out to characterize system performance. Then, as a proof of concept, we used the system to manipulate IOP in tree shrews (Tupaia belangeri while video of the retinal vessels was recorded and the caliber of a selected vein was quantified. Modulating IOP using our system elicited a rapid change in the appearance of the retinal vein of interest: IOP was lowered from 10 to 3 mmHg, and retinal vein caliber sharply increased as IOP decreased from 7 to 5 mmHg. Another important feature of this technology is its capability to measure ocular compliance and outflow facility in vivo, as demonstrated in tree shrews. Collectively, these proof-of-concept demonstrations support the utility of this system to manipulate IOP for a variety of useful applications in ocular biomechanics, and provide a framework for further study of the mechanisms of retinal venous pulsation.

Circadian Rhythm Connections to Oxidative Stress: Implications for Human Health

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Wilking, Melissa; Ndiaye, Mary; Mukhtar, Hasan

2013-01-01

Abstract Significance: Oxygen and circadian rhythmicity are essential in a myriad of physiological processes to maintain homeostasis, from blood pressure and sleep/wake cycles, down to cellular signaling pathways that play critical roles in health and disease. If the human body or cells experience significant stress, their ability to regulate internal systems, including redox levels and circadian rhythms, may become impaired. At cellular as well as organismal levels, impairment in redox regulation and circadian rhythms may lead to a number of adverse effects, including the manifestation of a variety of diseases such as heart diseases, neurodegenerative conditions, and cancer. Recent Advances: Researchers have come to an understanding as to the basics of the circadian rhythm mechanism, as well as the importance of the numerous species of oxidative stress components. The effects of oxidative stress and dysregulated circadian rhythms have been a subject of intense investigations since they were first discovered, and recent investigations into the molecular mechanisms linking the two have started to elucidate the bases of their connection. Critical Issues: While much is known about the mechanics and importance of oxidative stress systems and circadian rhythms, the front where they interact has had very little research focused on it. This review discusses the idea that these two systems are together intricately involved in the healthy body, as well as in disease. Future Directions: We believe that for a more efficacious management of diseases that have both circadian rhythm and oxidative stress components in their pathogenesis, targeting both systems in tandem would be far more successful. Antioxid. Redox Signal. 19, 192–208 PMID:23198849

Selective loss of orientation column maps in visual cortex during brief elevation of intraocular pressure.

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Chen, Xin; Sun, Chao; Huang, Luoxiu; Shou, Tiande

2003-01-01

To compare the orientation column maps elicited by different spatial frequency gratings in cortical area 17 of cats before and during brief elevation of intraocular pressure (IOP). IOP was elevated by injecting saline into the anterior chamber of a cat's eye through a syringe needle. The IOP was elevated enough to cause a retinal perfusion pressure (arterial pressure minus IOP) of approximately 30 mm Hg during a brief elevation of IOP. The visual stimulus gratings were varied in spatial frequency, whereas other parameters were kept constant. The orientation column maps of the cortical area 17 were monocularly elicited by drifting gratings of different spatial frequencies and revealed by a brain intrinsic signal optical imaging system. These maps were compared before and during short-term elevation of IOP. The response amplitude of the orientation maps in area 17 decreased during a brief elevation of IOP. This decrease was dependent on the retinal perfusion pressure but not on the absolute IOP. The location of the most visible maps was spatial-frequency dependent. The blurring or loss of the pattern of the orientation maps was most severe when high-spatial-frequency gratings were used and appeared most significantly on the posterior part of the exposed cortex while IOP was elevated. However, the basic patterns of the maps remained unchanged. Changes in cortical signal were not due to changes in the optics of the eye with elevation of IOP. A stable normal IOP is essential for maintaining normal visual cortical functions. During a brief and high elevation of IOP, the cortical processing of high-spatial-frequency visual information was diminished because of a selectively functional decline of the retinogeniculocortical X pathway by a mechanism of retinal circulation origin.

Retropupillary iris claw intraocular lens implantation in aphakia for dislocated intraocular lens

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Faria MY

2016-08-01

Full Text Available Mun Yueh Faria,1–3 Nuno Pinto Ferreira,1–3 Joana Medeiros Pinto,1–3 David Cordeiro Sousa,1–3 Ines Leal,1–3 Eliana Neto,1–3 Carlos Marques-Neves1–3 1Centro de Estudos da Visão, Universidade de Lisboa, 2Department of Ophthalmology, Hospital de Santa Maria, 3Faculty of Medicine, University of Lisbon, Lisbon, Portugal Background: Nowadays, dislocated intraocular lenses (IOLs and inadequate capsular support are becoming a challenge for every ophthalmic surgeon. Explantation of dislocated IOL and iris claw IOL (ICIOL are the techniques that have been used in our ophthalmic department. The aim of this study is to report our technique for retropupillar ICIOL.Methods: This study is a retrospective case series. A total of 105 eyes with dislocated IOL from the patients at the Department of Ophthalmology in Santa Maria Hospital, a tertiary reference hospital in Lisbon, Portugal, from January 2012 until January 2016, had been analyzed. Of these 105 eyes, 66 eyes had dislocated one-piece IOL and 39 eyes had dislocated three-piece IOL. The latter underwent iris suture of the same IOL and were excluded from this study. The remaining 66 eyes with dislocated one-piece IOL underwent pars plana vitrectomy, that is, explantation of dislocated IOL through corneal incision and an implantation of retropupillary ICIOL. Operative data and postoperative outcomes included best corrected visual acuity, IOL position, intraocular pressure, pigment dispersion, clinical signs of endothelial cell loss, and anterior chamber depth.Results: The mean follow-up was 23 months (range: 6–48 months. The mean preoperative best corrected visual acuity was 1.260±0.771 logMAR, and postoperative best corrected visual acuity was 0.352±0.400 logMAR units. Mean vision gain was 0.909 logMar units. The patients had the following complications: 1 retinal detachment was found in one patient, 2 corneal edema was found in three patients, 3 high intraocular pressure was observed in

Evaluation of a contact lens-embedded sensor for intraocular pressure measurement.

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Twa, Michael D; Roberts, Cynthia J; Karol, Huikai J; Mahmoud, Ashraf M; Weber, Paul A; Small, Robert H

2010-08-01

To evaluate a novel contact lens-embedded pressure sensor for continuous measurement of intraocular pressure (IOP). Repeated measurements of IOP and ocular pulse amplitude (OPA) were recorded in 12 eyes of 12 subjects in sitting and supine positions using 3 configurations of the dynamic contour tonometer: slit-lamp mounted (DCT), hand-held (HH), and contact lens-embedded sensor (CL). The IOP and OPA for each condition were compared using repeated measures ANOVA and the 95% limits of agreement were calculated. The sitting IOP (mean and 95% CI) for each configuration was DCT: 16.3 mm Hg (15.6 to 17.1 mm Hg), HH: 16.6 mm Hg (15.6 to 17.6 mm Hg), and CL: 15.7 mm Hg (15 to 16.3 mm Hg). The sitting OPA for each configuration was DCT: 2.4 mm Hg (2.1 to 2.6 mm Hg), HH: 2.4 mm Hg (2.1 to 2.7 mm Hg), and CL: 2.1 mm Hg (1.8 to 2.3 mm Hg). Supine IOP and OPA measurements with the CL and HH sensors were both greater than their corresponding sitting measurements, but were significantly less with the CL sensor than the HH sensor. The mean difference and 95% Limits of Agreement were smallest for the DCT and CL sensor comparisons (0.7+/-3.9 mm Hg) and widest for the CL and HH sensors (-1.9+/-7.25 mm Hg); these wider limits were attributed to greater HH measurement variability. The CL sensor was comparable to HH and DCT sensors with sitting subjects and is a viable method for measuring IOP and OPA. Supine measurements of IOP and OPA were greater than sitting conditions and were comparatively lower with the CL sensor. HH measurements were more variable than CL measurements and this influenced the Limits of Agreement for both sitting and supine conditions.

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

OpenAIRE

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...

24 Hours chronomics of ambulatory blood pressure and its relation with circadian rhythm of 6-sulfatoxy melatonin in night shift health care workers

OpenAIRE

B. Anjum; Narsingh Verma; Sandeep Tiwari; Abbas A Mahdi; Ranjana Singh; Qulsoom Naaz; Saumya Mishra; Prerna Singh; Suman Gautam; Shipra Bhardwaj

2015-01-01

Background: Night shift workers have altered circadian pattern of blood pressure/heart rate and hormones like melatonin and cortisol. Due to this variation, night shift worker suffers from various cardiovascular disorders and hormonal disturbances. Methods: The Present study was aimed to investigate the effects of rotating night shift on 24 hours chronomics of BP/HR and its relation with 6-sulfatoxy melatonin levels. 62 healthy nursing professionals, aged 20-40 year, performing day and ni...

Intravitreal triamcinolone for intraocular inflammation and associated macular edema

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Steven M Couch

2008-11-01

Full Text Available Steven M Couch, Sophie J BakriMayo Clinic Department of Ophthalmology, Mayo Clinic, Rochester, MN, USAAbstract: Triamcinolone acetonide (TA is a corticosteroid that has many uses in the treatment of ocular diseases because of its potent anti-inflammatory and anti-permeability actions. Intraocular inflammation broadly referred to as uveitis can result from several causes, including the immune system and after ophthalmic surgery. One of the most common reasons for vision loss with uveitis is macular edema. TA has been used for many years as an intravitreal injection for the treatment of ocular diseases. Several case control studies have been reported showing the efficacy of TA in the treatment of intraocular inflammation and associated macular edema caused by Behcet’s disease, Vogt-Koyanagi-Harada syndrome, sympathetic ophthalmia and white dot syndromes. It has also been shown efficacious in cases of pars planitis and idiopathic posterior uveitis. Some authors have reported its use in postoperative cystoid macular edema. Many of the studies on the use of TA in controlling intraocular inflammation and concomitant macular edema showed its effect to be transient in many patients requiring reinjection. Complications can arise from intravitreal injection of TA including elevated intraocular pressure and cataract. Rarely, it can be associated with infectious and non-infectious endophthalmitis. TA may be useful as an adjuvant in the treatment of uveitis and its associated macular edema, especially in patients resistant or intolerant to standard treatment.Keywords: triamcinolone acetonide, Behcet’s disease, sympathetic ophthalmia, Vogt-Koyanagi-Harada syndrome, white dot syndromes, uveitis, cataract surgery, macular edema, endophthalmitis

The Effect of a Diving Mask on Intraocular Pressure in a Healthy Population

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Catherina Josephine Goenadi

2016-06-01

Full Text Available Purpose: Swimming goggles increase the intraocular pressure (IOP via the periorbital frame pressure and suction effect. In comparison, diving masks have a larger frame rim and incorporate the nose. The exact effect(s of diving masks on IOP is unknown. This study evaluates the influence of diving masks on IOP in normal, healthy subjects. Methods: Tonometry was performed in both eyes of all subjects with an AVIA®Tono-Pen by a single investigator. Measurements were taken at baseline without the diving mask and with the subjects wearing a small-volume, double-window diving mask, but with the mask lenses removed. Two IOP readings in each eye were measured, and an additional reading was measured if the difference between the initial 2 was ≥2 mm Hg. Central corneal thickness (CCT was also measured in each eye, using a contact pachymeter (OcuScan®Alcon. Results: Forty eyes of 20 healthy volunteers (age 29.7 ± 9.3 years; range 21–52 were included. The mean CCT was 544.4 ± 43.5 µm. The mean IOP before the diving mask was worn had been 17.23 ± 2.18 mm Hg (n = 40. The IOP decreased by 0.43 mm Hg (p < 0.05 to 16.80 ± 2.57 mm Hg after the diving mask had been put on. There was no correlation between IOP change and age (r = 0.143, p = 0.337, gender (r = –0.174, p = 0.283 or CCT (r = –0.123, p = 0.445. Conclusion: There was no increase in IOP after the diving mask had been worn. A small but statistically significant decrease in IOP was observed. This study demonstrates that unlike swimming goggles, the strap tension and frame pressure on the periorbital tissue from a diving mask does not increase IOP. Diving masks may be a suitable alternative to swimming goggles for patients with advanced glaucoma or glaucoma filtration surgery.

Intraocular lymphoma

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Li-Juan Tang

2017-08-01

Full Text Available Intraocular lymphoma (IOL is a rare lymphocytic malignancy which contains two main distinct forms. Primary intraocular lymphoma (PIOL is mainly a sub-type of primary central nervous system lymphoma (PCNSL. Alternatively, IOL can originate from outside the central nervous system (CNS by metastasizing to the eye. These tumors are known as secondary intraocular lymphoma (SIOL. The IOL can arise in the retina, uvea, vitreous, Bruch’s membrane and optic nerve. There are predominantly of B-cell origin; however there are also rare T-cell variants. Diagnosis remains challenging for ophthalmologists and pathologists, due to its ability to masquerade as noninfectious or infectious uveitis, white dot syndromes, or occasionally as other metastatic cancers. Laboratory tests include flow cytometry, immunocytochemistry, interleukin detection (IL-10: IL-6, ratio >1, and polymerase chain reaction (PCR amplification. Methotrexate-based systemic chemotherapy with external beam radiotherapy and intravitreal chemotherapy with methotrexate are useful for controlling the disease, but the prognosis remains poor. Therefore, it is important to make an early diagnose and treatment. This review is focused on the clinical manifestations, diagnosis, treatment and prognosis of the IOL.

Advanced pigment dispersion glaucoma secondary to phakic intraocular collamer lens implant.

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Ye, Clara; Patel, Cajal K; Momont, Anna C; Liu, Yao

2018-06-01

We report a case of pigment dispersion glaucoma secondary to uncomplicated phakic intraocular collamer lens (ICL) (Visian ICL™, Staar Inc., Monrovia, CA) implant that resulted in advanced visual field loss. A 50-year-old man presented for routine follow-up status post bilateral phakic intraocular collamer lens (ICL) placement 8 years earlier. He was incidentally found to have a decline in visual acuity from an anterior subcapsular cataract and elevated intraocular pressure (IOP) in the left eye. There were signs of pigment dispersion and no evidence of angle closure. Diffuse optic nerve thinning was consistent with advanced glaucomatous visual field defects. Pigment dispersion was also present in the patient's right eye, but without elevated IOP or visual field defects. The patient was treated with topical glaucoma medications and the phakic ICL in the left eye was removed concurrently with cataract surgery to prevent further visual field loss. Pigment dispersion glaucoma is a serious adverse outcome after phakic ICL implantation and regular post-operative monitoring may prevent advanced visual field loss.

[Circadian rhythm : Influence on Epworth Sleepiness Scale score].

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Herzog, M; Bedorf, A; Rohrmeier, C; Kühnel, T; Herzog, B; Bremert, T; Plontke, S; Plößl, S

2017-02-01

The Epworth Sleepiness Scale (ESS) is frequently used to determine daytime sleepiness in patients with sleep-disordered breathing. It is still unclear whether different levels of alertness induced by the circadian rhythm influence ESS score. The aim of this study is to investigate the influence of circadian rhythm-dependent alertness on ESS performance. In a monocentric prospective noninterventional observation study, 97 patients with suspected sleep-disordered breathing were investigated with respect to daytime sleepiness in temporal relationship to polysomnographic examination and treatment. The Karolinska Sleepiness Scale (KSS) and the Stanford Sleepiness Scale (SSS) served as references for the detection of present sleepiness at three different measurement times (morning, noon, evening), prior to and following a diagnostic polysomnography night as well as after a continuous positive airway pressure (CPAP) titration night (9 measurements in total). The KSS, SSS, and ESS were performed at these times in a randomized order. The KSS and SSS scores revealed a circadian rhythm-dependent curve with increased sleepiness at noon and in the evening. Following a diagnostic polysomnography night, the scores were increased compared to the measurements prior to the night. After the CPAP titration night, sleepiness in the morning was reduced. KSS and SSS reflect the changes in alertness induced by the circadian rhythm. The ESS score war neither altered by the intra-daily nor by the inter-daily changes in the level of alertness. According to the present data, the ESS serves as a reliable instrument to detect the level of daytime sleepiness independently of the circadian rhythm-dependent level of alertness.

Non-contact tonometry synchronized with cardiac rhythm and its relationship with blood pressure.

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Queirós, A; González-Méijome, J M; Fernandes, P; Jorge, J; Almeida, J B; Parafita, M A

2006-07-01

The main objectives of this study were to determine the differences between non-synchronized intraocular pressure (IOP_N) and intraocular pressure readings synchronized with cardiac pulse and try to determine if these parameters are related to blood pressure values. One hundred and sixty-five right eyes from 165 volunteers (107 females, 58 males) aged from 19 to 73 years (mean +/- S.D., 29.93 +/- 11.17) were examined with the Nidek NT-4000, a new non-contact tonometer that allows the measurement of IOP synchronized with the cardiac rhythm. IOP measurements in the four different modes of synchronization were taken in a randomized order. Three measures of each parameter were taken and then averaged. The blood pressure was determined three times with a portable manometer and mean values of systolic and diastolic pressure and the pulse rate were computed. Mean arterial pressure (MAP) was determined as being 1/3 of systolic plus 2/3 of diastolic blood pressure. The mean +/- S.D. values for the standard intraocular pressure (IOP_N: 14.76 +/- 2.86), intraocular pressure in the systolic instant or peak (IOP_P: 14.99 +/- 2.85), intraocular pressure in the middle instant between heartbeats or middle (IOP_M: 14.68 +/- 2.76), and intraocular pressure in the diastolic instant or bottom (IOP_B: 13.86 +/- 2.61) were obtained. The IOP_P was higher than the remaining values. A significant difference in mean IOP existed between IOP_B and the remaining modes of measuring (p non-synchronized and the remaining synchronized parameters in a significant way. Other than a weak association with MAP, no significant correlation between IOP and BP was found. The measurements of IOP readings for the three modes are consistent with timings during the cardiac cycle and IOP pulse cycle.

The Risk of Intraocular Pressure Elevation in Pediatric Non-infectious Uveitis

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Kothari, Srishti; Foster, C. Stephen; Pistilli, Maxwell; Liesegang, Teresa L.; Daniel, Ebenezer; Sen, H. Nida; Suhler, Eric B.; Thorne, Jennifer E.; Jabs, Douglas A.; Levy-Clarke, Grace A.; Nussenblatt, Robert B.; Rosenbaum, James T.; Lawrence, Scott D.; Kempen, John H.

2015-01-01

Purpose To characterize the risk and risk factors for intraocular pressure (IOP) elevation in pediatric non-infectious uveitis. Design Multi-center retrospective cohort study. Participants Nine hundred sixteen children (1593 eyes) uveitis followed between January 1978 through December 2007 at five academic uveitis centers in United States. Methods Medical records review by trained, certified experts. Main outcome measures Prevalence and incidence of IOP≥21 and ≥30mmHg and incidence of a rise in IOP by ≥10mmHg. To avoid under ascertainment, outcomes were counted as present when IOP-lowering therapies were in use. Results Initially 251 (15.8%) and 46 eyes (2.9%) had IOP≥21 and ≥30mmHg, respectively. Factors associated with presenting IOP elevation included age 6–12 years (versus other pediatric ages), prior cataract surgery (adjusted odds ratio≥21mmHg [aOR21]=2.42, P=0.01), pars plana vitrectomy (adjusted odds ratio≥30mmHg[aOR30]=11.1, P=0.03), duration of uveitis ≥6 months (aORs30 up to 11.8, Puveitis. Statistically significant risk factors include IOP elevation or use of IOP-lowering treatment in the contralateral eye and local corticosteroid use – that demonstrated a dose-and route of administration-dependent relationship. In contrast, use of immunosuppressive drug therapy did not increase such risk. Pediatric eyes with non-infectious uveitis should be followed closely for IOP elevation when strong risk factors such as the use of local corticosteroids and contralateral IOP elevation are present. PMID:26233626

Changes in blood pressure and sleep duration in patients with blue light-blocking/yellow-tinted intraocular lens (CHUKYO study).

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Ichikawa, Kazuo

2014-07-01

Blood pressure and sleep duration may be influenced by retinal light exposure. Cataracts may exert such an influence by decreasing the transparency of the crystalline lens. A large-scale clinical study was conducted to examine changes in blood pressure and sleep duration after intraocular lens (IOL) implantation during cataract surgery and to investigate how different types of IOL influence the degree of these effects. Using a questionnaire, we collected information, including blood pressure measurement and sleep duration, from 1367 patients (1367 eyes) before IOL implantation, 1 week after IOL implantation and 1 month after IOL implantation. Systolic and diastolic blood pressures were significantly decreased in the total patient group after implantation. The decrease in systolic blood pressure 1 month after implantation was significantly more in patients who received a yellow-tinted IOL than it was in those who received an ultraviolet (UV) light-filtering IOL. The post-implantation sleep duration, including naps, became shorter in patients who had slept too much and became longer in those who had slept too little before IOL implantation. Our observations suggest that a yellow-tinted IOL is better for patients with high blood pressure than a UV light-filtering IOL. Furthermore, the yellow-tinted IOL is as good as the UV light-filtering IOL for improving sleep duration. A pale yellow-tinted IOL is likely to be superior to a moderate yellow-tinted IOL in terms of allowing patients to discriminate different colors. Thus, the pale yellow-tinted IOL appears to be better for patients than the UV light-filtering IOL and the moderate yellow-tinted IOL.

The Effects of Ramadan Fasting on Anterior Segment Parameters, Visual Acuity and Intraocular Pressures of the Eye.

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Selver, Ozlem Barut; Palamar, Melis; Gerceker, Kevser; Egrilmez, Sait; Yagci, Ayse

2017-01-01

It is aimed to determine whether fasting during Ramadan has any significant effect on anterior chamber parameters, visual acuity and intraocular pressures. 31 fasting (Group 1) and 30 non-fasting healthy volunteers (Group 2) were enrolled. All cases underwent an ophthalmological examination and anterior segment parameter evaluation (central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), pupil size) with Pentacam before and after the breaking of the Ramadan fast in Group 1, before and after dinner in Group 2. The mean age was 43.35 ± 13.20 in Group 1, 43.17 ± 12.90 in Group 2 (p= 0.955). No significant difference was detected in any of the parameters in both groups. There is a need for more detailed and associated studies to understand better about the influence of Ramadan fast on various ocular parameters.

Intraocular pressure decrease with preservative-free fixed and unfixed combination of tafluprost and timolol in pseudoexfoliative glaucoma.

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Holló, Gábor; Ropo, Auli

2015-01-01

We investigated the intraocular pressure (IOP) lowering efficacy of preservative-free fixed and non-fixed combination of tafluprost 0.0015% and timolol 0.5% in pseudoexfoliative glaucoma (XFG). A per protocol worse eye analysis was made on all XFG patients who participated in a recent 6 month, prospective, randomized, double-masked, parallel group, multicenter phase III study. The mean time-wise IOP decreased by 8.62 to 10.25 mmHg (31.8 to 36.7%) in the fixed dose combination arm (15 patients) and by 5.38 to 11.35 mmHg (21.3 to 41.2%) in the non-fixed combination arm (13 patients), respectively (p preservative-free fixed dose combination of tafluprost and timolol provides a clinically significant IOP reduction in XFG, and may offer an advantage for the XFG patients with dry eye, due to its preservative-free nature.

Circadian clocks, epigenetics, and cancer

KAUST Repository

Masri, Selma; Kinouchi, Kenichiro; Sassone-Corsi, Paolo

2015-01-01

The interplay between circadian rhythm and cancer has been suggested for more than a decade based on the observations that shift work and cancer incidence are linked. Accumulating evidence implicates the circadian clock in cancer survival and proliferation pathways. At the molecular level, multiple control mechanisms have been proposed to link circadian transcription and cell-cycle control to tumorigenesis.The circadian gating of the cell cycle and subsequent control of cell proliferation is an area of active investigation. Moreover, the circadian clock is a transcriptional system that is intricately regulated at the epigenetic level. Interestingly, the epigenetic landscape at the level of histone modifications, DNA methylation, and small regulatory RNAs are differentially controlled in cancer cells. This concept raises the possibility that epigenetic control is a common thread linking the clock with cancer, though little scientific evidence is known to date.This review focuses on the link between circadian clock and cancer, and speculates on the possible connections at the epigenetic level that could further link the circadian clock to tumor initiation or progression.

Circadian Rhythm Sleep Disorders

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Erhan Akinci

2016-06-01

Full Text Available The circadian rhythm sleep disorders define the clinical conditions where sleep and ndash;wake rhythm is disrupted despite optimum environmental and social conditions. They occur as a result of the changes in endogenous circadian hours or non-compatibility of environmental factors or social life with endogenous circadian rhythm. The sleep and ndash;wake rhythm is disrupted continuously or in repeating phases depending on lack of balance between internal and external cycles. This condition leads to functional impairments which cause insomnia, excessive sleepiness or both in people. Application of detailed sleep anamnesis and sleep diary with actigraphy record, if possible, will be sufficient for diagnosis. The treatment aims to align endogenous circadian rhythm with environmental conditions. The purpose of this article is to review pathology, clinical characteristics, diagnosis and treatment of circadian rhythm disorder. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(2: 178-189

Intraocular pressure, blood pressure, and retinal blood flow autoregulation: a mathematical model to clarify their relationship and clinical relevance.

Science.gov (United States)

Guidoboni, Giovanna; Harris, Alon; Cassani, Simone; Arciero, Julia; Siesky, Brent; Amireskandari, Annahita; Tobe, Leslie; Egan, Patrick; Januleviciene, Ingrida; Park, Joshua

2014-05-29

This study investigates the relationship between intraocular pressure (IOP) and retinal hemodynamics and predicts how arterial blood pressure (BP) and blood flow autoregulation (AR) influence this relationship. A mathematical model is developed to simulate blood flow in the central retinal vessels and retinal microvasculature as current flowing through a network of resistances and capacitances. Variable resistances describe active and passive diameter changes due to AR and IOP. The model is validated by using clinically measured values of retinal blood flow and velocity. The model simulations for six theoretical patients with high, normal, and low BP (HBP-, NBP-, LBP-) and functional or absent AR (-wAR, -woAR) are compared with clinical data. The model predicts that NBPwAR and HBPwAR patients can regulate retinal blood flow (RBF) as IOP varies between 15 and 23 mm Hg and between 23 and 29 mm Hg, respectively, whereas LBPwAR patients do not adequately regulate blood flow if IOP is 15 mm Hg or higher. Hemodynamic alterations would be noticeable only if IOP changes occur outside of the regulating range, which, most importantly, depend on BP. The model predictions are consistent with clinical data for IOP reduction via surgery and medications and for cases of induced IOP elevation. The theoretical model results suggest that the ability of IOP to induce noticeable changes in retinal hemodynamics depends on the levels of BP and AR of the individual. These predictions might help to explain the inconsistencies found in the clinical literature concerning the relationship between IOP and retinal hemodynamics. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Movement of retinal vessels toward the optic nerve head after increasing intraocular pressure in monkey eyes with experimental glaucoma.

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Kuroda, Atsumi; Enomoto, Nobuko; Ishida, Kyoko; Shimazawa, Masamitsu; Noguchi, Tetsuro; Horai, Naoto; Onoe, Hirotaka; Hara, Hideaki; Tomita, Goji

2017-09-01

A shift or displacement of the retinal blood vessels (RBVs) with neuroretinal rim thinning indicates the progression of glaucomatous optic neuropathy. In chronic open angle glaucoma, individuals with RBV positional shifts exhibit more rapid visual field loss than those without RBV shifts. The retinal vessels reportedly move onto the optic nerve head (ONH) in response to glaucoma damage, suggesting that RBVs are pulled toward the ONH in response to increased cupping. Whether this phenomenon only applies to RVBs located in the vicinity or inside the ONH or, more generally, to RBVs also located far from the ONH, however, is unclear. The aim of this study was to evaluate the movement of RBVs located relatively far from the ONH edge after increasing intraocular pressure (IOP) in an experimental monkey model of glaucoma. Fundus photographs were obtained in 17 monkeys. High IOP was induced in the monkeys by laser photocoagulation burns applied uniformly with 360° irradiation around the trabecular meshwork of the left eye. The right eye was left intact and used as a non-treated control. Considering the circadian rhythm of IOP, it was measured in both eyes of each animal at around the same time-points. Then, fundus photographs were obtained. Using Image J image analysis software, an examiner (N.E.) measured the fundus photographs at two time-points, i.e. before laser treatment (time 1) and the last fundus photography after IOP elevation (time 2). The following parameters were measured (in pixels): 1) vertical diameter of the ONH (DD), 2) distance from the ONH edge to the first bifurcation point of the superior branch of the central retinal vein (UV), 3) distance from the ONH edge to the first bifurcation point of the inferior branch of the central retinal vein (LV), 4) ONH area, and 5) surface area of the cup of the ONH. We calculated the ratios of UV to DD (UV/DD), LV to DD (LV/DD), and the cup area to disc area ratio (C/D). The mean UV/DD at time 1 (0.656 ± 0.233) was

Aging and Circadian Rhythms

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Duffy, Jeanne F.; Zitting, Kirsi-Marja; Chinoy, Evan D.

2015-01-01

Aging is associated with numerous changes, including changes in sleep timing, duration, and quality. The circadian timing system interacts with a sleep-wake homeostatic system to regulate human sleep, including sleep timing and structure. Here, we review key features of the human circadian timing system, age-related changes in the circadian timing system, and how those changes may contribute to the observed alterations in sleep. PMID:26568120

Chronobiometric assessment of autogenic training effects upon blood pressure and heart rate.

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Watanabe, Y; Halberg, F; Cornélissen, G; Saito, Y; Fukuda, K; Otsuka, K; Kikuchi, T

1996-12-01

Autogenic training, a method of self-hypnosis, lowers the extent of within-day variation of systolic blood pressure assessed by the circadian double amplitude. The blood pressure and heart rate of ten patients, conventionally diagnosed as having hypertension or white-coat hypertension, were automatically monitored at 30-min intervals for 7 days before autogenic training and again for 7 days, at 1 or 2 months after the start of autogenic training (practiced three times daily). The circadian double amplitude of systolic blood pressure of the patients investigated was 3 to 17 mm Hg lower on autogenic training. In 5 patients, reductions by 7 to 17 mm Hg were statistically significant. These results are regarded as provisional statistics, the utility of which depends on replication. By contrast, the over-all group reduction of the circadian double amplitude of systolic blood pressure by 8 mm Hg on the average can be taken at face value. Autogenic training also lowered the circadian double amplitude of diastolic blood pressure, but the effect was small as was the effect of autogenic training upon the MESOR (a rhythm adjusted mean) and acrophase (a measure of the timing of over-all high values recurring each day). The effect of autogenic training upon the circadian double amplitude of systolic blood pressure suggests its trial as first-line treatment of patients with an excessive circadian blood pressure amplitude, a condition which, even in the absence of an elevated 24-hr, average of blood pressure, is associated with a large increase in the risk of developing ischemic stroke or nephropathy.

A new design and application of bioelastomers for better control of intraocular pressure in a glaucoma drainage device.

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Luong, Quang Minh; Shang, Lei; Ang, Marcus; Kong, Jen Fong; Peng, Yan; Wong, Tina T; Venkatraman, Subbu S

2014-02-01

Glaucoma drainage device (GDD) implantation is an effective method of lowering the intraocular pressure (IOP). Commonly used GDDs can be classified into nonvalved and valved. Although a stable IOP is critical, currently available devices often cause extreme IOP fluctuations: nonvalved GDDs suffer from a risk of hypotony (IOP22 mmHg). It is hypothesized that a GDD with a valve designed to open around the time of onset of the hypertensive phase, would minimize IOP fluctuation. Accordingly, a valve fabricated from a biodegradable polymer poly(L-lactide-co-ϵ-caprolactone) (PLC 70/30) is evaluated in vitro and in vivo. The pressure response is compared with its non-degradable counterpart in in vitro studies of IOP. It is also established that in vitro, the biodegradability of the valve is programmed to occur over 12 weeks. In vivo, a steady and low IOP is achieved with the biodegradable valve and the hypertensive phase is significantly attenuated compared with the commercial device. Fibrotic encapsulation of the device is also minimized with the biodegradable valve in vivo. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Circadian physiology of metabolism.

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Panda, Satchidananda

2016-11-25

A majority of mammalian genes exhibit daily fluctuations in expression levels, making circadian expression rhythms the largest known regulatory network in normal physiology. Cell-autonomous circadian clocks interact with daily light-dark and feeding-fasting cycles to generate approximately 24-hour oscillations in the function of thousands of genes. Circadian expression of secreted molecules and signaling components transmits timing information between cells and tissues. Such intra- and intercellular daily rhythms optimize physiology both by managing energy use and by temporally segregating incompatible processes. Experimental animal models and epidemiological data indicate that chronic circadian rhythm disruption increases the risk of metabolic diseases. Conversely, time-restricted feeding, which imposes daily cycles of feeding and fasting without caloric reduction, sustains robust diurnal rhythms and can alleviate metabolic diseases. These findings highlight an integrative role of circadian rhythms in physiology and offer a new perspective for treating chronic diseases in which metabolic disruption is a hallmark. Copyright © 2016, American Association for the Advancement of Science.

The effect of lateral decubitus position on nocturnal intraocular pressure over a habitual 24-hour period in healthy adults.

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Jie Hao

Full Text Available PURPOSE: To investigate the effect of lateral decubitus position (LDP on nocturnal intraocular pressure (IOP and the effect of LDP on 24-hour habitual IOP pattern in healthy subjects. METHODS: Intraocular pressure was measured every 2-hours using an Accupen Applanation Tonometer (Accutome, USA. During the diurnal period (7:30 am, 9:30 am, 11:30 am, 1:30 pm, 3:30 pm, 5:30 pm, 7:30 pm, and 9:30 pm, IOP was measured in the sitting position under bright light (500-1000 lux after the subjects had been seated for 5 min. The nocturnal IOP was measured in the supine position, right LDP, and left LDP, with randomized sequences, under dim light (<10 lux at 11:30 pm, 1:30 am, 3:30 am, and 5:30 am. The subjects were awakened and maintained each position for 5 min before the measurement. The 24-hour habitual IOP patterns were obtained according to the nocturnal position (supine, right LDP and left LDP for either eye. P<0.05 was considered to be significant. RESULTS: Nineteen healthy subjects were included with a mean age of 51.3±5.8 years. During the nocturnal period, a significant IOP difference was found between the dependent eye (the eye on the lower side of LDP and the supine position, but not for all the nocturnal time points. Over a 24-hour period, the effect of LDP on habitual IOP pattern was not statistically significant, although the mean nocturnal IOP and the diurnal-nocturnal IOP change for the right and the left eye in the LDP pattern was slightly higher than that in the sitting-supine pattern. CONCLUSION: Significant nocturnal IOP differences existed between the dependent eye and the supine, but did not occur consistently for all time points. Over a 24-hour period, the effect of LDP on habitual IOP pattern was not statistically significant in healthy subjects.

Repeatability and Reproducibility of Intraocular Pressure and Dynamic Corneal Response Parameters Assessed by the Corvis ST

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Bernardo T. Lopes

2017-01-01

Full Text Available Purpose. To assess the repeatability and reproducibility of dynamic corneal response parameters measured by the Corvis ST (Oculus, Wetzlar, Germany. Methods. One eye randomly selected from 32 healthy volunteers was examined by the Corvis ST. Three different devices were used in an alternated random order for taking three measurements at each device in each subject. Standard intraocular pressure (IOP, the biomechanical-compensated IOP (bIOP, and DCR parameters were evaluated. The within-subject standard deviation (ζw and coefficient of variation (CV were assessed. Results. Regarding pressure indices, the ζw was below 1 mmHg for repeatability (0.98 for IOP and 0.89 for bIOP and the CV was 6.6% for IOP and 6.1% for bIOP. For reproducibility, the ζw was around 1 mmHg (1.12 for IOP and 1.05 for bIOP and the CV was 7.6% for IOP and 7.1% for bIOP. Most of DCR indices presented CV for repeatability below 4%. For reproducibility, the CV of most of the indices were below 6%. The deformation amplitude (DA ratio in 1 mm and integrated radius were below 4% (1.2% and 3.8%, resp.. Conclusions. The Corvis ST showed good precision (repeatability and reproducibility for IOP measurements and for DCR in healthy eyes.

Intraocular pressure asymmetry is not a clinically-significant feature when using the PULSAIR non-contact tonometer.

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Pointer, J S

1997-11-01

This report describes the results of a retrospective analysis of intraocular pressure (i.o.p.) values recorded from the right (R) and left (L) eyes of middle-aged and elderly at-risk but assumed non-glaucomatous subjects. The tensions had been measured using the Keeler PULSAIR non-contact tonometer (NCT) in the course of routine optometric practice when individuals attended for a sight test. These bilateral IOP data were collated on the basis of each subject's gender, (male/female), age (40-59 years/60+ years) and the time of the tonometry assessment (a.m./p.m.). Wherever possible material was equi-partitioned across these three bipartite variables producing balanced data groupings. Pair-wise testing of R versus L absolute values of pneumo-applanation pressures across any of the balanced data groupings failed to reveal a statistically-significant difference between the paired IOP distributions. There was a consistent but small relative IOP asymmetry (L > R) in these data. Further analysis indicated that this asymmetry only attained borderline statistical significance with respect to subject's age: neither gender nor the time of assessment were statistically significant features, and there were no statistically-significant interactions between any of the three variables. In conclusion, provided that the manufacturer's operating instructions are adhered to, IOP asymmetry is not a clinically-significant feature when using the PULSAIR NCT on a clinical population at risk of developing glaucoma.

Circadian disorganization alters intestinal microbiota.

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Robin M Voigt

Full Text Available Intestinal dysbiosis and circadian rhythm disruption are associated with similar diseases including obesity, metabolic syndrome, and inflammatory bowel disease. Despite the overlap, the potential relationship between circadian disorganization and dysbiosis is unknown; thus, in the present study, a model of chronic circadian disruption was used to determine the impact on the intestinal microbiome. Male C57BL/6J mice underwent once weekly phase reversals of the light:dark cycle (i.e., circadian rhythm disrupted mice to determine the impact of circadian rhythm disruption on the intestinal microbiome and were fed either standard chow or a high-fat, high-sugar diet to determine how diet influences circadian disruption-induced effects on the microbiome. Weekly phase reversals of the light:dark (LD cycle did not alter the microbiome in mice fed standard chow; however, mice fed a high-fat, high-sugar diet in conjunction with phase shifts in the light:dark cycle had significantly altered microbiota. While it is yet to be established if some of the adverse effects associated with circadian disorganization in humans (e.g., shift workers, travelers moving across time zones, and in individuals with social jet lag are mediated by dysbiosis, the current study demonstrates that circadian disorganization can impact the intestinal microbiota which may have implications for inflammatory diseases.

Post-transcriptional control of the mammalian circadian clock: implications for health and disease.

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Preußner, Marco; Heyd, Florian

2016-06-01

Many aspects of human physiology and behavior display rhythmicity with a period of approximately 24 h. Rhythmic changes are controlled by an endogenous time keeper, the circadian clock, and include sleep-wake cycles, physical and mental performance capability, blood pressure, and body temperature. Consequently, many diseases, such as metabolic, sleep, autoimmune and mental disorders and cancer, are connected to the circadian rhythm. The development of therapies that take circadian biology into account is thus a promising strategy to improve treatments of diverse disorders, ranging from allergic syndromes to cancer. Circadian alteration of body functions and behavior are, at the molecular level, controlled and mediated by widespread changes in gene expression that happen in anticipation of predictably changing requirements during the day. At the core of the molecular clockwork is a well-studied transcription-translation negative feedback loop. However, evidence is emerging that additional post-transcriptional, RNA-based mechanisms are required to maintain proper clock function. Here, we will discuss recent work implicating regulated mRNA stability, translation and alternative splicing in the control of the mammalian circadian clock, and its role in health and disease.

Relationship between intraocular pressure and angle configuration: an anterior segment OCT study.

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Chong, Rachel S; Sakata, Lisandro M; Narayanaswamy, Arun K; Ho, Sue-Wei; He, Mingguang; Baskaran, Mani; Wong, Tien Yin; Perera, Shamira A; Aung, Tin

2013-03-05

To assess the relationship between intraocular pressure (IOP) and anterior chamber angle (ACA) configuration as assessed by gonioscopy and anterior segment optical coherence tomography (AS-OCT). A total of 2045 subjects aged 50 years and older, were recruited from a community clinic and underwent AS-OCT, Goldmann applanation tonometry, and gonioscopy. A quadrant was classified as closed on gonioscopy if the posterior trabecular meshwork could not be seen. A closed quadrant on AS-OCT was defined by the presence of any contact between the iris and angle wall anterior to the scleral spur. Customized software (Zhongshan Angle Assessment Program, Guangzhou, China) was used to measure AS-OCT parameters on AS-OCT scans, including anterior chamber depth, area, and volume; iris thickness (IT) and curvature; lens vault; angle opening distance; and trabecular-iris space area. IOP values were adjusted for age, sex, diabetes and hypertension status, body mass index, central corneal thickness, and presence of peripheral anterior synechiae. Mean age of study subjects was 63.2 ± 8.0 years, 52.6% were female, and 89.4% were Chinese. Mean IOP was 14.8 ± 2.4 mm Hg (range 826). IOP (mean ± SE) increased with number of quadrants with gonioscopic angle closure (none: 14.6 ± 0.2; one: 14.7 ± 0.3; two: 15.0 ± 0.3; three: 15.0 ± 0.3; four: 15.6 ± 0.3 mm Hg; P gonioscopy, with increasing IOP.

Applanation optical coherence elastography: noncontact measurement of intraocular pressure, corneal biomechanical properties, and corneal geometry with a single instrument

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Singh, Manmohan; Han, Zhaolong; Nair, Achuth; Schill, Alexander; Twa, Michael D.; Larin, Kirill V.

2017-02-01

Current clinical tools provide critical information about ocular health such as intraocular pressure (IOP). However, they lack the ability to quantify tissue material properties, which are potent markers for ocular tissue health and integrity. We describe a single instrument to measure the eye-globe IOP, quantify corneal biomechanical properties, and measure corneal geometry with a technique termed applanation optical coherence elastography (Appl-OCE). An ultrafast OCT system enabled visualization of corneal dynamics during noncontact applanation tonometry and direct measurement of micro air-pulse induced elastic wave propagation. Our preliminary results show that the proposed Appl-OCE system can be used to quantify IOP, corneal biomechanical properties, and corneal geometry, which builds a solid foundation for a unique device that can provide a more complete picture of ocular health.

Intraocular pressure spike after YAG iridotomy in patients with pigment dispersion.

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Birt, Catherine M

2004-04-01

The role of laser peripheral iridotomy to break a suspected reverse pupil block in the long-term control of pigment dispersion is promising, but the usefulness of this procedure has not been completely established. The author examined whether patients with pigment dispersion are at higher risk for an intraocular pressure (IOP) spike after laser peripheral iridotomy due to possible compromise of trabecular meshwork function, compared with patients undergoing prophylactic peripheral iridotomy for an occludable angle. Data were collected prospectively on the first eye of 87 patients with occludable angles and 13 patients with pigment dispersion treated with peripheral laser iridotomy between November 1995 and October 1996 at the glaucoma service of a university-affiliated hospital in Toronto. All patients received one drop of 0.5% apraclonidine before the procedure. IOP was measured before and 1 and 24 hours after the procedure. There was no difference between the two groups in the distribution of right vs. left eyes, sex, race, the mean total energy required to produce a patent iridotomy, the mean number of medications used or the mean IOP before the procedure. The patients with pigment dispersion were significantly younger than those with occludable angles (mean age [and standard deviation (SD)] 40.5 [9.45] years vs. 66.4 [10.78] years) (p pigment dispersion group had an IOP spike greater than 2 mm Hg after the procedure (p = 0.001). Among these patients, the mean IOP (36.4 [SD 10.83] mm Hg vs. 30.3 [SD 7.04] mm Hg, p = 0.05) and the mean rise in IOP (14.0 [SD 10.63] mm Hg vs. 8.7 [SD 4.73] mm Hg, p = 0.04) were significantly higher in those with pigment dispersion than in those with occludable angles. Among the patients who used antiglaucoma medications before the procedure or had a prelaser IOP level greater than 22 mm Hg, those with pigment dispersion were more likely than those with occludable angles to have an IOP spike at 1 hour (p pigment dispersion

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

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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.

Postural effects on intraocular pressure and ocular perfusion pressure in patients with non-arteritic anterior ischemic optic neuropathy.

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Yang, Jee Myung; Park, Sang Woo; Ji, Yong Sok; Kim, Jaeryung; Yoo, Chungkwon; Heo, Hwan

2017-04-20

To investigate postural effects on intraocular pressure (IOP) and ocular perfusion pressure (OPP) in patients with non-arteritic ischemic optic neuropathy (NAION). IOP and blood pressure (BP) were measured in 20 patients with unilateral NAION 10 min after changing to each of the following positions sequentially: sitting, supine, right lateral decubitus position (LDP), supine, left LDP, and supine. IOP was measured using a rebound tonometer and OPP was calculated using formulas based on mean BP. The dependent LDP (DLDP) was defined as the position when the eye of interest (affected or unaffected eye) was placed on the dependent side in the LDP. IOPs were significantly higher (P = 0.020) and OPPs were significantly lower (P = 0.041) in the affected eye compare with the unaffected eye, with the affected eye in DLDP. Compared with the mean IOP of the unaffected eyes, the mean IOP of the affected eyes increased significantly (+2.9 ± 4.4 versus +0.7 ± 3.1 mmHg, respectively; P = 0.003) and the mean OPP decreased significantly (-6.7 ± 9.4 versus -4.9 ± 8.0 mmHg, respectively; P = 0.022) after changing positions from supine to DLDP. In addition, changing position from supine to DLDP showed significantly larger absolute changes in IOP (4.13 ± 3.19 mmHg versus 2.51 ± 1.92 mmHg, respectively; P = 0.004) and OPP (9.86 ± 5.69 mmHg versus 7.50 ± 5.49 mmHg, respectively; P = 0.009) in the affected eye compared with the unaffected eye. In the affected eye, there was a significant positive correlation between absolute change in IOP and OPP when changing position from supine to DLDP (Rho = 0.512, P = 0.021). A postural change from supine to DLDP caused significant fluctuations in IOP and OPP of the affected eye, and may significantly increase IOP and decrease OPP. Posture-induced IOP changes may be a predisposing factor for NAION development.

Comparison of intraocular pressure measurements with different contact tonometers in young healthy persons

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Saulius Galgauskas

2016-01-01

Full Text Available AIM: To analyze the correlation of Goldmann applanation tonometer (GAT, I-Care tonometer and Tono-Pen tonometer results in young healthy persons, and to investigate the influence of central corneal thickness (CCT on intraocular pressure (IOP measurements recorded with these tonometers. METHODS: We conducted a pilot clinical study in 78 eyes of 78 subjects aged 22-28 years old (44 women and 34 men; mean age 23.8±1.19y. IOP was measured using GAT, I-Care and Tono-Pen tonometers, followed by measurements of CCT. Statistical analysis was performed using SPSS 20.0. RESULTS: The mean IOPs and standard deviation (±SD for GAT, I-Care and Tono-Pen were 15.62±2.281 mm Hg, 16.29±2.726 mm Hg and 16.32±2.393 mm Hg, respectively. The mean CCT was 555.15±29.648 μm. Clear positive correlations between GAT and I-Care, GAT and Tono-Pen, and I-Care and Tono-Pen tonometers were found (r=0.867, P0.05. Both non-gold standard tonometers were affected by CCT; that is, both I-Care and Tono-Pen tonometer values were significantly higher with higher CCT means (>555 μm; MD=−1.282, P555 μm were associated with overestimated IOP values.

Intraocular pressure readings obtained through soft contact lenses using four types of tonometer.

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Takenaka, Joji; Kunihara, Eriko; Rimayanti, Ulfah; Tanaka, Junko; Kaneko, Makoto; Kiuchi, Yoshiaki

2015-01-01

To compare the reliability and accuracy of intraocular pressure (IOP) measured while wearing soft contact lenses (SCLs) using a non-contact tonometer (NCT), Goldmann applanation tonometer (GAT), iCare rebound tonometer (RBT) and the Tono-Pen XL. Twenty-six healthy subjects were examined. The IOP was measured using NCT, GAT, RBT, and the Tono-Pen XL, while the subjects wore SCLs -5.00 D, -0.50 D and +5.00 D. Bland-Altman plots and a regression analysis were used to compare the IOPs obtained with those instruments and the IOPs of the naked eyes measured using GAT (the standard IOPs in this study). The IOPs obtained by the Tono-Pen XL while the subjects were wearing -5.00 D, -0.50 D, and +5.00 D SCLs were significantly higher than those of the naked eyes obtained using GAT. RBT showed that the IOPs were similar to the GAT standard IOPs under all conditions. The IOPs measured with NCT and GAT while the subjects were wearing -5.00 D and -0.50 D SCLs were similar to the GAT standard IOPs. The IOPs obtained with RBT and NCT while the subjects were wearing -5.00 D and -0.50 D SCLs exhibited a good correlation with the standard IOPs. The NCT and RBT are best when measuring IOP through hydrogel SCLs.

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

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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.

Tear production and intraocular pressure in canine eyes with corneal ulceration

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David L. Williams

2017-05-01

Full Text Available This study aimed to evaluate changes in lacrimation and intraocular pressure (IOP in dogs with unilateral corneal ulceration using the Schirmer tear test (STT and rebound (TonoVet® tonometry. IOP and STT values were recorded in both ulcerated and non-ulcerated (control eyes of 100 dogs diagnosed with unilateral corneal ulceration. Dogs presented with other ocular conditions as their primary complaint were excluded from this study. The mean ± standard deviation for STT values in the ulcerated and control eyes were 20.2±4.6 mm/min and 16.7±3.5 mm/min respectively. The mean ± standard deviation for IOP in the ulcerated and control eyes were 11.9±3.1 mmHg and 16.7±2.6 mmHg respectively. STT values were significantly higher (p<0.000001 in the ulcerated eye compared to the control eye while IOP was significantly lower (p<0.0001. There is an increase in lacrimation and a decrease in IOP in canine eyes with corneal ulceration. The higher tear production in ulcerated eyes shows the importance of measuring STT in both eyes in cases of corneal ulceration, since this increased lacrimation may mask an underlying keratoconjunctivitis sicca only evident in the contralateral eye. The lower IOP in ulcerated eyes is likely to relate to mild uveitic change in the ulcerated eye with a concomitant increase in uveoscleral aqueous drainage. While these changes in tear production and IOP in ulcerated eyes are widely recognised in both human and veterinary ophthalmology, it appears that this is the first controlled documented report of these changes in a large number of individuals.

Intraocular pressure measurement with the noncontact tonometer through soft contact lenses.

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Liu, Yi-Chun; Huang, Jehn-Yu; Wang, I-Jong; Hu, Fung-Rong; Hou, Yu-Chih

2011-03-01

To assess the accuracy of measuring intraocular pressure (IOP) through a soft contact lens (SCL) with different refractive powers using a noncontact tonometer (NCT). Thirty-two healthy adult volunteers free of glaucoma or corneal disease participated in this study. IOP was measured in the right eyes without SCLs and with different lens powers, from -3.0 to -12.0 D as measured by NCT. IOP of the left eyes was also measured, as an internal control. Corneal curvature was measured in both eyes using an autokeratometer. Sixteen volunteers wore one brand of SCL (group A) and the other 16 wore a different brand, with 2 different curvatures (groups B and C). Statistical data were analyzed by SPSS using the Wilcoxon signed rank test for comparison of IOP readings and multiple linear regression analysis for the relationship among power of contact lenses, corneal power, and difference in IOP measurements. The difference in mean IOP between eyes without lenses and those with lenses was statistically significant in lens with -6.0 D and below in all 3 groups. The decrease in IOP significantly correlated with the refractive power of contact lenses in all 3 groups. The difference in IOP measurements was influenced by the mean K in group A but not in group B or C. There was no statistically significant difference in the IOP measurements in the left eyes or in the mean K between the right and left eyes. IOP measurement through myopic SCLs by NCT may be inaccurate and tends toward underestimation, especially in high myopic lenses. A strong relationship exists between IOP reduction and myopic lens power.

Intraocular pressure measurement by three different tonometers in primary congenital glaucoma.

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Zareei, Athar; Razeghinejad, Mohammad Reza; Nowroozzadeh, Mohammad Hosein; Mehrabi, Yadollah; Aghazadeh-Amiri, Mohammad

2015-01-01

To determine the agreement between intraocular pressure (IOP) measurements using an automated non-contact tonometer (NCT), Goldmann applanation tonometer (GAT), and the ocular response analyzer (ORA) in subjects with primary congenital glaucoma (PCG). Twenty-nine eyes of 17 PCG patients underwent IOP measurements using NCT, GAT and ORA. Variables obtained by the ORA were corneal-compensated IOP (IOPcc), Goldmann-correlated IOP (IOPg), corneal hysteresis (CH), and corneal resistance factor (CRF). A difference more than 1.5 mmHg for IOP was considered as clinically relevant. Mean age of the patients was 12 years. Mean IOP (±standard deviation, SD) was 15.3 ± 2.8 mmHg (GAT), 15.5 ± 6.0 (NCT), 19.2 ± 7.0 (IOPg), and 21.1 ± 7.9 (IOPcc); (P = 0.001). Except for NCT vs. GAT (P = 1.0), the average IOP difference between each pair of measurements was clinically relevant. The 95% limits of agreements were - 10.2 to 10.3 mmHg (NCT vs. GAT), -7.8 to 15.3 (IOPg vs. GAT), and - 8.1 to 19.0 (IOPcc vs. GAT). The differences in IOP measurements increased significantly with higher average IOP values (r = 0.715, P = 0.001, for NCT vs. GAT; r = 0.802, P < 0.001, for IOPg vs. GAT; and r = 0.806, P < 0.001, for IOPcc vs. GAT). CH showed a significant association with differences in IOP measurements only for IOPcc vs. GAT (r = 0.830, P < 0.001). Mean IOP obtained by NCT was not significantly different from that of GAT, but ORA measured IOPs were significantly higher than both other devices.

Circadian rhythm phase shifts and endogenous free-running circadian period differ between African-Americans and European-Americans.

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Eastman, Charmane I; Suh, Christina; Tomaka, Victoria A; Crowley, Stephanie J

2015-02-11

Successful adaptation to modern civilization requires the internal circadian clock to make large phase shifts in response to circumstances (e.g., jet travel and shift work) that were not encountered during most of our evolution. We found that the magnitude and direction of the circadian clock's phase shift after the light/dark and sleep/wake/meal schedule was phase-advanced (made earlier) by 9 hours differed in European-Americans compared to African-Americans. European-Americans had larger phase shifts, but were more likely to phase-delay after the 9-hour advance (to phase shift in the wrong direction). The magnitude and direction of the phase shift was related to the free-running circadian period, and European-Americans had a longer circadian period than African-Americans. Circadian period was related to the percent Sub-Saharan African and European ancestry from DNA samples. We speculate that a short circadian period was advantageous during our evolution in Africa and lengthened with northern migrations out of Africa. The differences in circadian rhythms remaining today are relevant for understanding and treating the modern circadian-rhythm-based disorders which are due to a misalignment between the internal circadian rhythms and the times for sleep, work, school and meals.

Association between central obesity and circadian parameters of blood pressure from the korean ambulatory blood pressure monitoring registry: Kor-ABP registry.

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Kang, In Sook; Pyun, Wook Bum; Shin, Jinho; Kim, Ju Han; Kim, Soon Gil; Shin, Gil Ja

2013-10-01

Central obesity has been reported as a risk for atherosclerosis and metabolic syndrome. The influence of central obesity on diurnal blood pressure (BP) has not been established. In this study, we investigated the influence of central obesity on the circadian parameters of BP by 24 hr ambulatory BP monitoring. Total 1,290 subjects were enrolled from the Korean Ambulatory BP registry. Central obesity was defined as having a waist circumference≥90 cm in males and ≥85 cm in females. The central-obese group had higher daytime systolic BP (SBP), nighttime SBP and diastolic BP (DBP) than the non-obese group (all, P<0.001). There were no differences in nocturnal dipping (ND) patterns between the groups. Female participants showed a higher BP mean difference (MD) than male participants with concerns of central obesity (daytime SBP MD 5.28 vs 4.27, nighttime SBP MD 6.48 vs 2.72) and wider pulse pressure (PP). Central obesity within the elderly (≥65 yr) also showed a higher BP MD than within the younger group (daytime SBP MD 8.23 vs 3.87, daytime DBP 4.10 vs 1.59). In conclusion, central obesity has no influence on nocturnal dipping patterns. However, higher SBP and wider PP are associated with central obesity, which is accentuated in women.

Circadian rhythm and its role in malignancy

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Mahmood Saqib

2010-03-01

Full Text Available Abstract Circadian rhythms are daily oscillations of multiple biological processes directed by endogenous clocks. The circadian timing system comprises peripheral oscillators located in most tissues of the body and a central pacemaker located in the suprachiasmatic nucleus (SCN of the hypothalamus. Circadian genes and the proteins produced by these genes constitute the molecular components of the circadian oscillator which form positive/negative feedback loops and generate circadian rhythms. The circadian regulation extends beyond clock genes to involve various clock-controlled genes (CCGs including various cell cycle genes. Aberrant expression of circadian clock genes could have important consequences on the transactivation of downstream targets that control the cell cycle and on the ability of cells to undergo apoptosis. This may lead to genomic instability and accelerated cellular proliferation potentially promoting carcinogenesis. Different lines of evidence in mice and humans suggest that cancer may be a circadian-related disorder. The genetic or functional disruption of the molecular circadian clock has been found in various cancers including breast, ovarian, endometrial, prostate and hematological cancers. The acquisition of current data in circadian clock mechanism may help chronotherapy, which takes into consideration the biological time to improve treatments by devising new therapeutic approaches for treating circadian-related disorders, especially cancer.

Circadian rhythms and obesity in mammals.

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Froy, Oren

2012-01-01

Obesity has become a serious public health problem and a major risk factor for the development of illnesses, such as insulin resistance and hypertension. Attempts to understand the causes of obesity and develop new therapeutic strategies have mostly focused on caloric intake and energy expenditure. Recent studies have shown that the circadian clock controls energy homeostasis by regulating the circadian expression and/or activity of enzymes, hormones, and transport systems involved in metabolism. Moreover, disruption of circadian rhythms leads to obesity and metabolic disorders. Therefore, it is plausible that resetting of the circadian clock can be used as a new approach to attenuate obesity. Feeding regimens, such as restricted feeding (RF), calorie restriction (CR), and intermittent fasting (IF), provide a time cue and reset the circadian clock and lead to better health. In contrast, high-fat (HF) diet leads to disrupted circadian expression of metabolic factors and obesity. This paper focuses on circadian rhythms and their link to obesity.

Circadian Rhythm Disruption Promotes Lung Tumorigenesis.

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Papagiannakopoulos, Thales; Bauer, Matthew R; Davidson, Shawn M; Heimann, Megan; Subbaraj, Lakshmipriya; Bhutkar, Arjun; Bartlebaugh, Jordan; Vander Heiden, Matthew G; Jacks, Tyler

2016-08-09

Circadian rhythms are 24-hr oscillations that control a variety of biological processes in living systems, including two hallmarks of cancer, cell division and metabolism. Circadian rhythm disruption by shift work is associated with greater risk for cancer development and poor prognosis, suggesting a putative tumor-suppressive role for circadian rhythm homeostasis. Using a genetically engineered mouse model of lung adenocarcinoma, we have characterized the effects of circadian rhythm disruption on lung tumorigenesis. We demonstrate that both physiologic perturbation (jet lag) and genetic mutation of the central circadian clock components decreased survival and promoted lung tumor growth and progression. The core circadian genes Per2 and Bmal1 were shown to have cell-autonomous tumor-suppressive roles in transformation and lung tumor progression. Loss of the central clock components led to increased c-Myc expression, enhanced proliferation, and metabolic dysregulation. Our findings demonstrate that both systemic and somatic disruption of circadian rhythms contribute to cancer progression. Copyright © 2016 Elsevier Inc. All rights reserved.

Phakic iris-fixated intraocular lens placement in the anterior chamber: effects on aqueous flow.

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Repetto, Rodolfo; Pralits, Jan O; Siggers, Jennifer H; Soleri, Paolo

2015-05-01

Phakic intraocular lenses (pIOLs) are used for correcting vision; in this paper we investigate the fluid dynamical effects of an iris-fixated lens in the anterior chamber. In particular, we focus on changes in the wall shear stress (WSS) on the cornea and iris, which could be responsible for endothelial and pigment cell loss, respectively, and also on the possible increase of the intraocular pressure, which is known to correlate with the incidence of secondary glaucoma. We use a mathematical model to study fluid flow in the anterior chamber in the presence of a pIOL. The governing equations are solved numerically using the open source software OpenFOAM. We use an idealized standard geometry for the anterior chamber and a realistic geometric description of the pIOL. We consider separately the main mechanisms that produce fluid flow in the anterior chamber. The numerical simulations allow us to obtain a detailed description of the velocity and pressure distribution in the anterior chamber, and indicated that implantation of the pIOL significantly modifies the fluid dynamics in the anterior chamber. However, lens implantation has negligible influence on the intraocular pressure and does not produce a significant increase of the shear stress on the cornea, while the shear stress on the iris, although increased, is not enough to cause detachment of cells. We conclude that alterations in the fluid dynamics in the anterior chamber as a result of lens implantation are unlikely to be the cause of medical complications associated with its use.

Manipulating the Cellular Circadian Period of Arginine Vasopressin Neurons Alters the Behavioral Circadian Period.

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Mieda, Michihiro; Okamoto, Hitoshi; Sakurai, Takeshi

2016-09-26

As the central pacemaker in mammals, the circadian clock in the suprachiasmatic nucleus (SCN) of the hypothalamus is a heterogeneous structure consisting of multiple types of GABAergic neurons with distinct chemical identities [1, 2]. Although individual cells have a cellular clock driven by autoregulatory transcriptional/translational feedback loops of clock genes, interneuronal communication among SCN clock neurons is likely essential for the SCN to generate a highly robust, coherent circadian rhythm [1]. However, neuronal mechanisms that determine circadian period length remain unclear. The SCN is composed of two subdivisions: a ventral core region containing vasoactive intestinal peptide (VIP)-producing neurons and a dorsal shell region characterized by arginine vasopressin (AVP)-producing neurons. Here we examined whether AVP neurons act as pacemaker cells that regulate the circadian period of behavior rhythm in mice. The deletion of casein kinase 1 delta (CK1δ) specific to AVP neurons, which was expected to lengthen the period of cellular clocks [3-6], lengthened the free-running period of circadian behavior as well. Conversely, the overexpression of CK1δ specific to SCN AVP neurons shortened the free-running period. PER2::LUC imaging in slices confirmed that cellular circadian periods of the SCN shell were lengthened in mice without CK1δ in AVP neurons. Thus, AVP neurons may be an essential component of circadian pacemaker cells in the SCN. Remarkably, the alteration of the shell-core phase relationship in the SCN of these mice did not impair the generation per se of circadian behavior rhythm, thereby underscoring the robustness of the SCN network. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physical exercise, fitness and dietary pattern and their relationship with circadian blood pressure pattern, augmentation index and endothelial dysfunction biological markers: EVIDENT study protocol

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Nicolás Eguskiñe

2010-05-01

Full Text Available Abstract Background Healthy lifestyles may help to delay arterial aging. The purpose of this study is to analyze the relationship of physical activity and dietary pattern to the circadian pattern of blood pressure, central and peripheral blood pressure, pulse wave velocity, carotid intima-media thickness and biological markers of endothelial dysfunction in active and sedentary individuals without arteriosclerotic disease. Methods/Design Design: A cross-sectional multicenter study with six research groups. Subjects: From subjects of the PEPAF project cohort, in which 1,163 who were sedentary became active, 1,942 were sedentary and 2,346 were active. By stratified random sampling, 1,500 subjects will be included, 250 in each group. Primary measurements: We will evaluate height, weight, abdominal circumference, clinical and ambulatory blood pressure with the Radial Pulse Wave Acquisition Device (BPro, central blood pressure and augmentation index with Pulse Wave Application Software (A-Pulse and SphymgoCor System Px (Pulse Wave Analysis, pulse wave velocity (PWV with SphymgoCor System Px (Pulse Wave Velocity, nutritional pattern with a food intake frequency questionnaire, physical activity with the 7-day PAR questionnaire and accelerometer (Actigraph GT3X, physical fitness with the cycle ergometer (PWC-170, carotid intima-media thickness by ultrasound (Micromax, and endothelial dysfunction biological markers (endoglin and osteoprotegerin. Discussion Determining that sustained physical activity and the change from sedentary to active as well as a healthy diet improve circadian pattern, arterial elasticity and carotid intima-media thickness may help to propose lifestyle intervention programs. These interventions could improve the cardiovascular risk profile in some parameters not routinely assessed with traditional risk scales. From the results of this study, interventional approaches could be obtained to delay vascular aging that combine physical

Screening of intraocular pressure before routine pupil dilation for retinal photography: Clinical case report

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Lap-kin Chiang

2016-12-01

Full Text Available Introduction: Pharmacologic dilation of the pupil results in twice the sensitivity of detection of diabetic retinopathy compared with undilated retinal examination. The potential risk of acute angle-closure glaucoma after pupil dilation has been hypothesized to be higher in Asian patients with diabetes mellitus. Clinical case: A 61-year-old man with diabetes mellitus and hypertension was incidentally found to have elevated intraocular pressure (IOP before routine retinal photography. He was asymptomatic and the visual acuity was 0.67 for both eyes. An ophthalmologist later found he had anatomical narrow-angle borderline glaucoma. Topical administration of pilocarpine and oral administration of acetazolamide were initiated, and laser iridotomy was later performed. IOP screening: Among 1736 diabetic and/or hypertensive patients who underwent IOP screening, 31 patients (1.8% had IOP of any eye persistently higher than 21 mm Hg on at least two occasions. The mean (standard deviation IOP of the right eye was 24.1 (2.1 mm Hg, while that of the left eye was 24.6 (2.5 mm Hg. Four patients (12.9% were found to have glaucoma, and treatment was initiated by an ophthalmologist. Therefore further study should be conducted to evaluate the cost-effectiveness of IOP screening among this group of patients.

Neurobiology of circadian systems.

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Schulz, Pierre; Steimer, Thierry

2009-01-01

Time is a dimension tightly associated with the biology of living species. There are cycles of varied lengths in biological activities, from very short (ultradian) rhythms to rhythms with a period of approximately one day (circadian) and rhythms with longer cycles, of a week, a month, a season, or even longer. These rhythms are generated by endogenous biological clocks, i.e. time-keeping structures, rather than being passive reactions to external fluctuations. In mammals, the suprachiasmatic nucleus (SCN) is the major pacemaker. The pineal gland, which secretes melatonin, is the major pacemaker in other phyla. There also exist biological clocks generating circadian rhythms in peripheral tissues, for example the liver. A series of clock genes generates the rhythm through positive and negative feedback effect of proteins on their own synthesis, and this system oscillates with a circadian period. External factors serve as indicators of the astronomical (solar) time and are called zeitgebers, literally time-givers. Light is the major zeitgeber, which resets daily the SCN circadian clock. In the absence of zeitgebers, the circadian rhythm is said to be free running; it has a period that differs from 24 hours. The SCN, together with peripheral clocks, enables a time-related homeostasis, which can become disorganized in its regulation by external factors (light, social activities, food intake), in the coordination and relative phase position of rhythms, or in other ways. Disturbances of rhythms are found in everyday life (jet lag, shift work), in sleep disorders, and in several psychiatric disorders including affective disorders. As almost all physiological and behavioural functions in humans occur on a rhythmic basis, the possibility that advances, delays or desynchronization of circadian rhythms might participate in neurological and psychiatric disorders has been a theme of research. In affective disorders, a decreased circadian amplitude of several rhythms as well as a

Effect of Qingguang'an II on expression of PAX6, Ngn1 and Ngn2 mRNA of rats with chronic high intraocular pressure

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Ya-Sha Zhou

2017-09-01

Full Text Available AIM: To remark the effect of Qingguang'an II on expression of PAX6, Ngn1, and Ngn2 mRNA of rats with chronic high intraocular pressure. METHODS: Totally 40 male SD rats were randomly divided into 6 groups, that was: A: blank group, B: model group, C: Qingguang'an II low dose group, D: Qingguang'an II moderate dose group, E: Qingguang'an II high dose group, F: Yimaikang disket group. B, C, D, E, F groups of experimental rats were established the model of chronic high intraocular pressure(IOPby cauterizing of superficial scleral vein. Animal model was established successfully by using monitoring IOP consistently keep above 25mmHg for 8wk as cut-off criterion. Tissues of Eyes were obtained after intragastric administration for 2wk and 4wk. The expressions of PAX6, Ngn1, and Ngn2 mRNA were investigated by Real-time PCR. RESULTS: At the time-point of 2wk, PAX6, Ngn1, and Ngn2 mRNA in group B were statistically expressed in lower level comparing with other groups(PPPP>0.05. CONCLUSION: In summar, Qingguang'an II and Yimaikang disket can remarkably increase the expressions of PAX6, Ngn1, and Ngn2, which suggest protecting the optic nerve of rats caused by chronic high IOP. What's more, this study indicated that, in the protection of optic nerve of rats with chronic high IOP, the high dose of Qingguang'an II at the time-point of 4wk was the better choice.

Circadian Rhythm Sleep-Wake Disorders.

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Abbott, Sabra M; Reid, Kathryn J; Zee, Phyllis C

2015-12-01

The circadian system regulates the timing and expression of nearly all biological processes, most notably, the sleep-wake cycle, and disruption of this system can result in adverse effects on both physical and mental health. The circadian rhythm sleep-wake disorders (CRSWDs) consist of 5 disorders that are due primarily to pathology of the circadian clock or to a misalignment of the timing of the endogenous circadian rhythm with the environment. This article outlines the nature of these disorders, the association of many of these disorders with psychiatric illness, and available treatment options. Copyright © 2015 Elsevier Inc. All rights reserved.

Exercise training prevents increased intraocular pressure and sympathetic vascular modulation in an experimental model of metabolic syndrome

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Castro, E.F.S.; Mostarda, C.T.; Rodrigues, B.; Moraes-Silva, I.C.; Feriani, D.J.; De Angelis, K.; Irigoyen, M.C.

2015-01-01

The present study aimed to study the effects of exercise training (ET) performed by rats on a 10-week high-fructose diet on metabolic, hemodynamic, and autonomic changes, as well as intraocular pressure (IOP). Male Wistar rats receiving fructose overload in drinking water (100 g/L) were concomitantly trained on a treadmill for 10 weeks (FT group) or kept sedentary (F group), and a control group (C) was kept in normal laboratory conditions. The metabolic evaluation comprised the Lee index, glycemia, and insulin tolerance test (KITT). Arterial pressure (AP) was measured directly, and systolic AP variability was performed to determine peripheral autonomic modulation. ET attenuated impaired metabolic parameters, AP, IOP, and ocular perfusion pressure (OPP) induced by fructose overload (FT vs F). The increase in peripheral sympathetic modulation in F rats, demonstrated by systolic AP variance and low frequency (LF) band (F: 37±2, 6.6±0.3 vs C: 26±3, 3.6±0.5 mmHg 2 ), was prevented by ET (FT: 29±3, 3.4±0.7 mmHg 2 ). Positive correlations were found between the LF band and right IOP (r=0.57, P=0.01) and left IOP (r=0.64, P=0.003). Negative correlations were noted between KITT values and right IOP (r=-0.55, P=0.01) and left IOP (r=-0.62, P=0.005). ET in rats effectively prevented metabolic abnormalities and AP and IOP increases promoted by a high-fructose diet. In addition, ocular benefits triggered by exercise training were associated with peripheral autonomic improvement

The association between circulating endostatin and a disturbed circadian blood pressure pattern in patients with type 2 diabetes.

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Wuopio, Jonas; Östgren, Carl Johan; Länne, Toste; Lind, Lars; Ruge, Toralph; Carlsson, Axel C; Larsson, Anders; Nyström, Fredrik H; Ärnlöv, Johan

2018-02-28

Endostatin, cleaved from collagen XVIII in the extracellular matrix, is a promising circulating biomarker for cardiovascular damage. It possesses anti-angiogenic and anti-fibrotic functions and has even been suggested to be involved in blood pressure regulation. Less is known if endostatin levels relate to circadian blood pressure patterns. In the present paper we studied the association between circulating levels of endostatin and nocturnal dipping in blood pressure. We used the CARDIPP-study, a cohort of middle aged, type 2 diabetics (n = 593, 32% women), with data on both 24-hour and office blood pressure, serum-endostatin, cardiovascular risk factors, and incident major cardiovascular events. Nocturnal dipping was defined as a >10% difference between day- and night-time blood pressures. Two-hundred four participants (34%) were classified as non-dippers. The mean endostatin levels were significantly higher in non-dippers compared to dippers (mean ± standard deviation: 62.6 ± 1.8 µg/l vs. 58.7 ± 1.6 µg/l, respectively, p = .007). Higher serum levels of endostatin were associated with a diminished decline in nocturnal blood pressure adjusted for age, sex, HbA1c, mean systolic day blood pressure, hypertension treatment, glomerular filtration rate, and prevalent cardiovascular disease (regression coefficient per SD increase of endostatin -0.01, 95% CI, -0.02-(-0.001), p = .03). Structural equation modelling analyses suggest that endostatin mediates 7% of the association between non-dipping and major cardiovascular events. We found an independent association between higher circulating levels of endostatin and a reduced difference between day- and night-time systolic blood pressure in patients with type 2 diabetes. Yet endostatin mediated only a small portion of the association between non-dipping and cardiovascular events arguing against a clinical utility of our findings.

Intraocular eyelashes and iris cyst in anterior chamber following penetrating eye injury: a case report

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Sahu S

2017-03-01

Full Text Available Sabin Sahu,1 Lila Raj Puri,1 Sanjay Kumar Singh2 1Department of Ophthalmology, Sagarmatha Choudhary Eye Hospital, Lahan, Siraha, 2Department of Ophthalmology, Biratnagar Eye Hospital, Biratnagar, Nepal Background: The presence of intraocular eyelashes following penetrating eye injury or ocular surgery is relatively uncommon. The response of the eye to intraocular eyelashes is variable. The eyelash may be symptomatic or may remain asymptomatic for long periods. Objective: We report a case with two intraocular eyelashes and an iris cyst after 2 years of asymptomatic period following penetrating eye injury. Case presentation: A 24-year-old male presented with decreased vision in the left eye which he had noticed for the previous 2 weeks. His visual acuity was 6/6 in the right eye and 6/18 in the left eye, improving to 6/9 with -2.5 DC × 140° correction. The intraocular pressure was 12 mmHg in both eyes. On slit-lamp examination, the left eye showed 8 mm linear peripheral corneal opacity nasally, two eyelashes in the superior anterior chamber, and an iris cyst measuring 4 mm × 4 mm in the superior iris. The right eye was normal. Dilated fundus examination of both eyes was normal. The eyelashes and cyst were removed surgically. There were no complications during the 3-month follow-up period. Conclusion: Intraocular implantation of eyelashes following penetrating eye injury can remain asymptomatic for long periods; however, late development of iris cyst may occur. Keywords: intraocular eyelashes, iris cyst, penetrating eye injury

Systemic Medication and Intraocular Pressure in a British Population

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Khawaja, Anthony P.; Chan, Michelle P.Y.; Broadway, David C.; Garway-Heath, David F.; Luben, Robert; Yip, Jennifer L.Y.; Hayat, Shabina; Wareham, Nicholas J.; Khaw, Kay-Tee; Foster, Paul J.

2014-01-01

Objective To determine the association between systemic medication use and intraocular pressure (IOP) in a population of older British men and women. Design Population-based, cross-sectional study. Participants We included 7093 participants from the European Prospective Investigation into Cancer–Norfolk Eye Study. Exclusion criteria were a history of glaucoma therapy (medical, laser, or surgical), IOP asymmetry between eyes of >5 mmHg, and missing data for any covariables. The mean age of participants was 68 years (range, 48–92) and 56% were women. Methods We measured IOP using the Ocular Response Analyzer. Three readings were taken per eye and the best signal value of the Goldmann-correlated IOP value considered. Participants were asked to bring all their medications and related documentation to the health examination, and these were recorded by the research nurse using an electronic case record form. The medication classes examined were angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, α-blockers, β-blockers, calcium channel blockers, diuretics, nitrates, statins, insulin, biguanides, sulfonylureas, aspirin, and other nonsteroidal anti-inflammatory drugs. We examined associations between medication use and IOP using multivariable linear regression models adjusted for age, sex, and body mass index. Models containing diabetic medication were further adjusted for glycosylated hemoglobin levels. Main Outcome Measures Mean IOP of the right and left eyes. Results Use of systemic β-blockers (−0.92 mmHg; 95% CI, −1.19, −0.65; Pnitrates (−0.63 mmHg; 95% CI, −1.12, −0.14; P = 0.011) were independently associated with lower IOP. The observed associations between statin or aspirin use with IOP were no longer significant after adjustment for β-blocker use. Conclusions This is the first population-based study to demonstrate and quantify clinically significant differences in IOP among participants using systemic β-blockers or

Influence on intraocular pressure of the postural change and daily activities in the early morning in suspected glaucoma patients

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Ting Chen

2014-05-01

Full Text Available AIM:To evaluate the influence on intraocular pressure(IOPof the postural change and daily activities in the early morning in suspected glaucoma patients.METHODS:The supine and sitting IOP were measured and analyzed on 51 suspected glaucoma patients(100 eyeswith Icare rebound tonometer before and after getting up and daily activities in the early morning. RESULTS: The mean of sitting IOP of 51 patients was 17.12±4.53mmHg, which was significantly lower than the mean of supine IOP(19.14±5.51mmHg. The mean of IOP before and after daily activity of 51 patients were 17.12±4.53mmHg and 14.44±3.90mmHg respectively, which showed significantly difference. CONCLUSION:Postural change and daily activities can result in significant changes of IOP in suspected glaucoma patients.

Measurement of intraocular pressure in healthy unanesthetized inland bearded dragons (Pogona vitticeps).

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Schuster, Eva J; Strueve, Julia; Fehr, Michael J; Mathes, Karina A

2015-06-01

To evaluate the use of rebound and applanation tonometry for the measurement of intraocular pressure (IOP) and to assess diurnal variations in and the effect of topical anesthesia on the IOP of healthy inland bearded dragons (Pogona vitticeps). 56 bearded dragons from 4 months to 11 years old. For each animal following an initial ophthalmic examination, 3 IOP measurements were obtained on each eye between 9 AM and 10 AM, 1 PM and 2 PM, and 5 PM and 7 PM by use of rebound and applanation tonometry. An additional measurement was obtained by rebound tonometry for each eye in the evening following the application of a topical anesthetic to evaluate changes in the tolerance of the animals to the tonometer. Descriptive data were generated, and the effects of sex, time of day, and topical anesthesia on IOP were evaluated. Bearded dragons did not tolerate applanation tonometry even following topical anesthesia. Median daily IOP as determined by rebound tonometry was 6.16 mm Hg (95% confidence interval, 5.61 to 6.44 mm Hg). The IOP did not differ significantly between the right and left eyes. The IOP was highest in the morning, which indicated that the IOP in this species undergoes diurnal variations. Topical anesthesia did not significantly affect IOP, but it did improve the compliance for all subjects. Results indicated that rebound tonometry, but not applanation tonometry, was appropriate for measurement of IOP in bearded dragons. These findings provided preliminary guidelines for IOP measurement and ophthalmic evaluation in bearded dragons.

A 5.2GHz, 0.5mW RF powered wireless sensor with dual on-chip antennas for implantable intraocular pressure monitoring

KAUST Repository

Arsalan, Muhammad; Ouda, Mahmoud H.; Marnat, Loic; Ahmad, Talha Jamal; Shamim, Atif; Salama, Khaled N.

2013-01-01

For the first time a single chip implantable wireless sensor system for Intraocular Pressure Monitoring (IOPM) is presented. This system-on-chip (SoC) is battery-free and harvests energy from incoming RF signals. The chip is self-contained and does not require external components or bond wires to function. This 1.4mm3 SoC has separate 2.4GHz-transmit and 5.2GHz-receive antennas, an energy harvesting module, a temperature sensor, a 7-bit TIQ Flash ADC, a 4-bit RFID, a power management and control unit, and a VCO transmitter. The chip is fabricated in a standard 6-metal 0.18μm CMOS process and is designed to work with a post-processed MEMS pressure sensor. It consumes 513μW of peak power and when implanted inside the eye, it is designed to communicate with an external reader using on-off keying (OOK). © 2013 IEEE.

A 5.2GHz, 0.5mW RF powered wireless sensor with dual on-chip antennas for implantable intraocular pressure monitoring

KAUST Repository

Arsalan, Muhammad

2013-06-01

For the first time a single chip implantable wireless sensor system for Intraocular Pressure Monitoring (IOPM) is presented. This system-on-chip (SoC) is battery-free and harvests energy from incoming RF signals. The chip is self-contained and does not require external components or bond wires to function. This 1.4mm3 SoC has separate 2.4GHz-transmit and 5.2GHz-receive antennas, an energy harvesting module, a temperature sensor, a 7-bit TIQ Flash ADC, a 4-bit RFID, a power management and control unit, and a VCO transmitter. The chip is fabricated in a standard 6-metal 0.18μm CMOS process and is designed to work with a post-processed MEMS pressure sensor. It consumes 513μW of peak power and when implanted inside the eye, it is designed to communicate with an external reader using on-off keying (OOK). © 2013 IEEE.

Circadian dysregulation in Parkinson's disease

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Aleksandar Videnovic

2017-01-01

Full Text Available Parkinson's disease (PD is the second most common neurodegenerative disorder that affects over one million individuals in the US alone. PD is characterized by a plethora of motor and non-motor manifestations, resulting from a progressive degeneration of dopaminergic neurons and disbalance of several other neurotransmitters. A growing body of evidence points to significant alterations of the circadian system in PD. This is not surprising given the pivotal role that dopamine plays in circadian regulation as well as the role of circadian influences in dopamine metabolism. In this review we present basic and clinical investigations that examined the function of the circadian system in PD.

Intraocular pressure monitoring by rebound tonometry in children with myopia.

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Weng, Jenchieh; Tsai, I-Lun; Kuo, Li-Lin; Tsai, Ching-Yao; Woung, Lin-Chung; Hsiao, Ya-Chuan

2017-01-01

Topical atropine treatment is generally accepted to retard the progression of myopia, but it is associated with side effects such as photophobia and elevation of intraocular pressure (IOP). IOP measurements in children are challenging. The traditional applanation tonometry by direct contact with the cornea will require patient's cooperation. The rebound tonometer, using a dynamic electromechanical method for measuring IOP, shows good correlation with traditional tonometry. The purpose of this study is to evaluate the IOP of myopic children under atropine treatment using rebound tonometer and to compare the characteristics between rebound tonometry and applanation tonometry. This study is a prospective study measuring IOP by rebound tonometer in myopic children under regular low-dose atropine treatment. We recruited children with refraction error showing myopia over -0.5 D with 0.15%, 0.3%, or 0.5% atropine eye drops use every night or every other night for myopia control. Children with treatment duration of atropine tonometer (Tono-Pen XL, Reichert) and rebound tonometer (ICARE). The reliability of rebound tonometer was analyzed with percentage. Comparison of IOP between rebound tonometer and applanation tonometry was presented. The rebound tonometry was well tolerated by all participants and caused no complaints, discomfort, or adverse events. Totally 42 myopic eyes of 42 subjects were included in the study. The average age of these participants was 10 years old, range from 5 to 16. Median = 10 years old. The average IOP of the right eye by rebound tonometer was 17.4 ± 3 mmHg, and 17.1 ± 3 mmHg by applanation tonometry. Nearly 19%, 33%, and 24% of difference of IOP readings between rebound tonometer and Tono-Pen applanation are within 0 mmHg, 1 mmHg, and 1-2 mmHg, respectively. Rebound tonometry has good correlation with applanation tonometry and 76.1% of differences between two tonometers are <2 mmHg. The advantage of drop-free rebound tonometry has made it

Intraocular pressure measurement by three different tonometers in primary congenital glaucoma

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Athar Zareei

2015-01-01

Full Text Available Purpose: To determine the agreement between intraocular pressure (IOP measurements using an automated non-contact tonometer (NCT, Goldmann applanation tonometer (GAT, and the ocular response analyzer (ORA in subjects with primary congenital glaucoma (PCG. Methods: Twenty-nine eyes of 17 PCG patients underwent IOP measurements using NCT, GAT and ORA. Variables obtained by the ORA were corneal-compensated IOP (IOPcc, Goldmann-correlated IOP (IOPg, corneal hysteresis (CH, and corneal resistance factor (CRF. A difference more than 1.5 mmHg for IOP was considered as clinically relevant. Results: Mean age of the patients was 12 years. Mean IOP (±standard deviation, SD was 15.3 ± 2.8 mmHg (GAT, 15.5 ± 6.0 (NCT, 19.2 ± 7.0 (IOPg, and 21.1 ± 7.9 (IOPcc; (P = 0.001. Except for NCT vs. GAT (P = 1.0, the average IOP difference between each pair of measurements was clinically relevant. The 95% limits of agreements were − 10.2 to 10.3 mmHg (NCT vs. GAT, −7.8 to 15.3 (IOPg vs. GAT, and − 8.1 to 19.0 (IOPcc vs. GAT. The differences in IOP measurements increased significantly with higher average IOP values (r = 0.715, P = 0.001, for NCT vs. GAT; r = 0.802, P < 0.001, for IOPg vs. GAT; and r = 0.806, P < 0.001, for IOPcc vs. GAT. CH showed a significant association with differences in IOP measurements only for IOPcc vs. GAT (r = 0.830, P < 0.001. Conclusion: Mean IOP obtained by NCT was not significantly different from that of GAT, but ORA measured IOPs were significantly higher than both other devices.

Comparison of intraocular pressure measurements with different contact tonometers in young healthy persons.

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Galgauskas, Saulius; Strupaite, Rasa; Strelkauskaite, Ernesta; Asoklis, Rimvydas

2016-01-01

To analyze the correlation of Goldmann applanation tonometer (GAT), I-Care tonometer and Tono-Pen tonometer results in young healthy persons, and to investigate the influence of central corneal thickness (CCT) on intraocular pressure (IOP) measurements recorded with these tonometers. We conducted a pilot clinical study in 78 eyes of 78 subjects aged 22-28 years old (44 women and 34 men; mean age 23.8±1.19y). IOP was measured using GAT, I-Care and Tono-Pen tonometers, followed by measurements of CCT. Statistical analysis was performed using SPSS 20.0. The mean IOPs and standard deviation (±SD) for GAT, I-Care and Tono-Pen were 15.62±2.281 mm Hg, 16.29±2.726 mm Hg and 16.32±2.393 mm Hg, respectively. The mean CCT was 555.15±29.648 µm. Clear positive correlations between GAT and I-Care, GAT and Tono-Pen, and I-Care and Tono-Pen tonometers were found (r=0.867, P0.05). Both non-gold standard tonometers were affected by CCT; that is, both I-Care and Tono-Pen tonometer values were significantly higher with higher CCT means (>555 µm; MD=-1.282, Ptonometers overestimated IOP compared with the GAT values. Either the I-Care or Tono-Pen tonometer could be used instead of GAT because there was no significant difference between their results. Higher CCT values (>555 µm) were associated with overestimated IOP values.

Intraocular inflammation in autoimmune diseases.

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Pras, Eran; Neumann, Ron; Zandman-Goddard, Gisele; Levy, Yair; Assia, Ehud I; Shoenfeld, Yehuda; Langevitz, Pnina

2004-12-01

The uveal tract represents the vascular organ of the eye. In addition to providing most of the blood supply to the intraocular structures, it acts as a conduit for immune cells, particularly lymphocytes, to enter the eye. Consequently, the uveal tract is represented in many intraocular inflammatory processes. Uveitis is probably a misnomer unless antigens within the uvea are the direct targets of the inflammatory process. A better term of the condition is "intraocular inflammation" (IOI). To review the presence of IOI in autoimmune diseases, the immunopathogenic mechanisms leading to disease, and treatment. We reviewed the English medical literature by using MEDLINE (1984-2003) employing the terms "uveitis," "intraocular inflammation," and "autoimmune diseases." An underlying autoimmune disease was identified in up to 40% of patients with IOI, and included spondyloarthropathies, Behcets disease, sarcoidosis, juvenile chronic arthritis, Vogt-Koyanagi-Harada syndrome (an inflammatory syndrome including uveitis with dermatologic and neurologic manifestations), immune recovery syndrome, and uveitis with tubulointerstitial disease. The immunopathogenesis of IOI involves enhanced T-cell response. Recently, guidelines for the use of immunosuppressive drugs for inflammatory eye disease were established and include: corticosteroids, azathioprine, methotrexate, mycophenolate mofetil, cyclosporine, tacrolimus, cyclophosphamide, and chlorambucil. New therapies with limited experience include the tumor necrosis factor alpha inhibitors, interferon alfa, monoclonal antibodies against lymphocyte surface antigens, intravenous immunoglobulin (IVIG), and the intraocular delivery of immunosuppressive agents. An underlying autoimmune disease was identified in up to 40% of patients with IOI. Immunosuppressive drugs, biologic agents, and IVIG are employed for the treatment of IOI in autoimmune diseases.

Use of a 350-mm2 Baerveldt glaucoma drainage device to maintain vision and control intraocular pressure in dogs with glaucoma: a retrospective study (2013-2016).

Science.gov (United States)

Graham, Kathleen L; Donaldson, David; Billson, Francis A; Billson, F Mark

2017-09-01

To evaluate the 350-mm 2 Baerveldt glaucoma drainage device (GDD) in dogs with refractory glaucoma when modifications to address postoperative hypotony (extraluminal ligature; intraluminal stent) and the fibroproliferative response (intraoperative Mitomycin-C; postoperative oral colchicine and prednisolone) are implemented as reported in human ophthalmology. Retrospective case series. Twenty-eight client-owned dogs (32 eyes) including seven dogs (nine eyes) with primary glaucoma and 21 dogs (23 eyes) with secondary glaucoma. The medical records of all dogs undergoing placement of a 350-mm 2 Baerveldt GDD at a veterinary ophthalmology referral service between 2013 and 2016 were reviewed. Signalment, diagnosis, duration and previous treatment of glaucoma, previous intraocular surgery, IOP, visual, and surgical outcomes were recorded. IOP was maintained glaucoma medication were required following surgery. Vision was retained in 18 of 27 (66.7%) eyes with vision at the time of surgery. No eyes that were blind at the time of surgery (n = 5) had restoration of functional vision. Complications following surgery included hypotony (26/32; 81.3%), intraocular hypertension (24/32; 75.0%), and fibrin formation within the anterior chamber (20/32; 62.5%). The average follow-up after placement of the GDD was 361.1 days (median 395.6 days). Efforts to minimize postoperative hypotony and address the fibroproliferative response following placement of a 350-mm 2 Baerveldt GDD showed an increased success rate to other reports of this device in dogs and offers an alternative surgical treatment for controlling intraocular pressure in dogs with glaucoma. © 2016 American College of Veterinary Ophthalmologists.

Circadian Rhythms in Cyanobacteria

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Golden, Susan S.

2015-01-01

SUMMARY Life on earth is subject to daily and predictable fluctuations in light intensity, temperature, and humidity created by rotation of the earth. Circadian rhythms, generated by a circadian clock, control temporal programs of cellular physiology to facilitate adaptation to daily environmental changes. Circadian rhythms are nearly ubiquitous and are found in both prokaryotic and eukaryotic organisms. Here we introduce the molecular mechanism of the circadian clock in the model cyanobacterium Synechococcus elongatus PCC 7942. We review the current understanding of the cyanobacterial clock, emphasizing recent work that has generated a more comprehensive understanding of how the circadian oscillator becomes synchronized with the external environment and how information from the oscillator is transmitted to generate rhythms of biological activity. These results have changed how we think about the clock, shifting away from a linear model to one in which the clock is viewed as an interactive network of multifunctional components that are integrated into the context of the cell in order to pace and reset the oscillator. We conclude with a discussion of how this basic timekeeping mechanism differs in other cyanobacterial species and how information gleaned from work in cyanobacteria can be translated to understanding rhythmic phenomena in other prokaryotic systems. PMID:26335718

Prospective Comparative Analysis of 4 Different Intraocular Pressure Measurement Techniques and Their Effects on Pressure Readings.

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Berk, Thomas A; Yang, Patrick T; Chan, Clara C

2016-10-01

To compare intraocular pressure (IOP) measurement using the Goldmann applanation tonometry (GAT) without fluorescein, with fluorescein strips, with fluorescein droplets, and IOP measurement with Tono-Pen Avia (TPA). This was a prospective comparative clinical analysis. It was performed in clinical practice. The study population consisted of 40 volunteer patients, 1 eye per patient. All patients who were 18 years and older having routine ophthalmological examination were eligible to participate. Active corneal abrasions and/or ulcers, previous glaucoma surgery, or prostheses interfering with GAT measurement were excluded. GAT IOP was measured first without fluorescein, then with fluorescein strip, then with fluorescein droplet, and finally with the TPA device. The main outcome measure was central corneal IOP. Mean±SD IOP measurements for GAT without fluorescein, with fluorescein strip, with fluorescein droplet, and for TPA groups were 12.65±3.01, 14.70±2.82, 15.78±2.64, and 16.33±3.08 mm Hg, respectively. Repeated-measures analysis of variance corrected with the Greenhouse-Geisser estimate ([Latin Small Letter Open E]=0.732) showed that measuring technique had a significant effect on IOP measurements (F2.20,85.59=34.66, P<0.001). The pairwise post hoc testing showed statistically significant mean differences (P≤0.001) between all techniques except when GAT with fluorescein droplet was compared with TPA (P=0.222). The Bland-Altman analyses showed 95% limits of agreement maximum potential discrepancies in measurement ranging from 5.89 mm Hg in the GAT with fluorescein strip versus droplet compared with 11.83 mm Hg in the GAT with fluorescein strip versus TPA comparison. IOP measurement technique significantly impacted the values obtained. The ophthalmologist should ensure consistent measurement technique to minimize variability when following patients.

Effect of persistent high intraocular pressure on microstructure and hydraulic permeability of trabecular meshwork

International Nuclear Information System (INIS)

Mei Xi; Ren Lin; Xu Qiang; Liu Zhi-Cheng; Zheng Wei

2015-01-01

As the aqueous humor leaves the eye, it first passes through the trabecular meshwork (TM). Increased flow resistance in this region causes elevation of intraocular pressure (IOP), which leads to the occurrence of glaucoma. To quantitatively evaluate the effect of high IOP on the configuration and hydraulic permeability of the TM, second harmonic generation (SHG) microscopy was used to image the microstructures of the TM and adjacent tissues in control (normal) and high IOP conditions. Enucleated rabbit eyes were perfused at a pressure of 60 mmHg to achieve the high IOP. Through the anterior chamber of the eye, in situ images were obtained from different depths beneath the surface of the TM. Porosity and specific surface area of the TM in control and high IOP conditions were then calculated to estimate the effect of the high pressure on the permeability of tissue in different depths. We further photographed the histological sections of the TM and compared the in situ images. The following results were obtained in the control condition, where the region of depth was less than 55 μm with crossed branching beams and large pores in the superficial TM. The deeper meshwork is a silk-like tissue with abundant fluorescence separating the small size of pores. The total thickness of pathway tissues composed of TM and juxtacanalicular (JCT) is more than 100 μm. After putting a high pressure on the inner wall of the eye, the TM region progressively collapses and decreases to be less than 40 μm. Fibers of the TM became dense, and the porosity at 34 μm in the high IOP condition is comparable to that at 105 μm in the control condition. As a consequent result, the permeability of the superficial TM decreases rapidly from 120 μm 2 to 49.6 μm 2 and that of deeper TM decreases from 1.66 μm 2 to 0.57 μm 2 . Heterogeneity reflected by descent in permeability reduces from 12.4 μm of the control condition to 3.74 μm of the high IOP condition. The persistently high IOP makes the

Exercise training prevents increased intraocular pressure and sympathetic vascular modulation in an experimental model of metabolic syndrome

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Castro, E.F.S. [Unidade de Hipertensão, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Mostarda, C.T. [Universidade Federal do Maranhão, São Luís, MA (Brazil); Rodrigues, B. [Laboratório do Movimento Humano, Universidade São Judas Tadeu, São Paulo, SP (Brazil); Moraes-Silva, I.C. [Unidade de Hipertensão, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Feriani, D.J. [Laboratório do Movimento Humano, Universidade São Judas Tadeu, São Paulo, SP (Brazil); De Angelis, K. [Laboratório de Fisiologia Translacional, Universidade Nove de Julho, São Paulo, SP (Brazil); Irigoyen, M.C. [Unidade de Hipertensão, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

2015-02-13

The present study aimed to study the effects of exercise training (ET) performed by rats on a 10-week high-fructose diet on metabolic, hemodynamic, and autonomic changes, as well as intraocular pressure (IOP). Male Wistar rats receiving fructose overload in drinking water (100 g/L) were concomitantly trained on a treadmill for 10 weeks (FT group) or kept sedentary (F group), and a control group (C) was kept in normal laboratory conditions. The metabolic evaluation comprised the Lee index, glycemia, and insulin tolerance test (KITT). Arterial pressure (AP) was measured directly, and systolic AP variability was performed to determine peripheral autonomic modulation. ET attenuated impaired metabolic parameters, AP, IOP, and ocular perfusion pressure (OPP) induced by fructose overload (FT vs F). The increase in peripheral sympathetic modulation in F rats, demonstrated by systolic AP variance and low frequency (LF) band (F: 37±2, 6.6±0.3 vs C: 26±3, 3.6±0.5 mmHg{sup 2}), was prevented by ET (FT: 29±3, 3.4±0.7 mmHg{sup 2}). Positive correlations were found between the LF band and right IOP (r=0.57, P=0.01) and left IOP (r=0.64, P=0.003). Negative correlations were noted between KITT values and right IOP (r=-0.55, P=0.01) and left IOP (r=-0.62, P=0.005). ET in rats effectively prevented metabolic abnormalities and AP and IOP increases promoted by a high-fructose diet. In addition, ocular benefits triggered by exercise training were associated with peripheral autonomic improvement.

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

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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

Relaxin 2 fails to lower intraocular pressure and to dilate retinal vessels in rats.

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Hampel, Ulrike; Träger, Katharina; Liu, Hanhan; Teister, Julia; Grus, Franz; Prokosch-Willing, Verena

2018-03-13

Recently, the vasodilator relaxin 2 has been introduced as a treatment for acute heart failure. However, its role on vessels of the eye and intraocular pressure (IOP) remains unclear though it has been hypothesized to induce a decrease IOP after intramuscular injection in humans. We aimed to test whether the hormone relaxin 2 lowers IOP and dilates retinal vessels in animals. The IOP of female Sprague-Dawley rats before and after application of relaxin 2 was measured using an Icare Tonolab device calibrated for rats. Recombinant human relaxin 2 in phosphate-buffered saline with 0.1% bovine serum albumin was either applied as eye drops (1000, 2000 or 3000 ng/ml), injected intravitreally (500 ng/ml) or intravenously (13.3 μg/kg body weight). Retinal vessel thickness was monitored using infrared fundus images compiled with optical coherence tomography (Heidelberg Engineering) before and several time points after application of relaxin 2. Neither topical nor intravitreous or intravenous application of relaxin 2 lowered the IOP or changed the arterial or venous vessel diameter after 1 or 3 h after application. Now that relaxin 2 is more easily available, the hormone came again into focus as a potential glaucoma therapeutic. However, our study in rats could not support the hypothesis that relaxin 2 lowers IOP or dilates retinal vessels.

Retropupillary iris-claw intraocular lens in ectopia lentis in Marfan syndrome

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Faria MY

2016-06-01

Full Text Available Mun Yueh Faria,1 Nuno Ferreira,2 Eliana Neto,1 1Vitreo Retinal Department, 2Ophthalmology Department, Santa Maria Hospital, Lisbon, Portugal Objective: To report visual outcomes, complication rate, and safety of retropupillary iris-claw intraocular lens (ICIOL in ectopia lentis in Marfan syndrome (MFS. Design: Retrospective study. Methods: Six eyes of three MFS patients with ectopia lentis underwent surgery for subluxation lens and retropupillary ICIOL implantation from October 2014 to October 2015 at the Department of Ophthalmology, Santa Maria Hospital in Lisbon, Portugal. Demographics, preoperative and postoperative best-corrected visual acuity (BCVA, and intraocular pressure were evaluated. Endothelium cell count was assessed using specular microscopy; anterior chamber depth was measured using Pentacam postoperatively; and intraocular lens position was viewed by ultrasound biomicroscopy. All patients were female; mean age was 20±14.264 years (range: 7–38 years. Results: The average follow-up period was 6.66 months (range: 4–16 months. Preoperative BCVA was 0.568±0.149 logMAR units, and postoperative BCVA was 0.066±0.121 logMAR units. The mean BCVA gain was –0.502±0.221 on the logMAR scale. Postoperative average astigmatism and intraocular pressure were 1.292±0.697 mmHg (range: 0.5–2.25 mmHg and 16 mmHg (range: 12–18 mmHg, respectively. The average endothelial cell density decreased from 3,121±178 cells/mm2 before surgery to 2,835±533 cells/mm2 after surgery (measured at last follow-up visit and in the last follow-up, representing an average endothelial cell loss of 9.16%. Mean anterior chamber depth was 4.01 mm (±0.77 mm, as measured by Pentacam. No complications were found intra- or postoperatively in any of the six studied eyes. Conclusion: Retropupillary ICIOL implantation is a safe and effective procedure in the treatment of aphakia in MFS eyes, without capsular support after surgery for ectopia lens. The six eyes that

21 CFR 886.3600 - Intraocular lens.

Science.gov (United States)

2010-04-01

... DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3600 Intraocular lens. (a) Identification. An intraocular lens is a device made of materials such as glass or plastic intended to be implanted to replace the natural lens of an eye. (b) Classification. Class III. (c) Date PMA or notice of completion of a...

21 CFR 886.4275 - Intraocular fluid.

Science.gov (United States)

2010-04-01

... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4275 Intraocular fluid. (a) Identification. An intraocular fluid is a device consisting of a nongaseous fluid intended to be introduced into the eye to aid... section 515 of the act is required before this device may be commercially distributed. See § 886.3. ...

Circadian Rhythms in Diet-Induced Obesity.

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Engin, Atilla

2017-01-01

The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronizes these with daily cycles, feeding patterns also regulates circadian clocks. The clock genes and adipocytokines show circadian rhythmicity. Dysfunction of these genes are involved in the alteration of these adipokines during the development of obesity. Food availability promotes the stimuli associated with food intake which is a circadian oscillator outside of the suprachiasmatic nucleus (SCN). Its circadian rhythm is arranged with the predictable daily mealtimes. Food anticipatory activity is mediated by a self-sustained circadian timing and its principal component is food entrained oscillator. However, the hypothalamus has a crucial role in the regulation of energy balance rather than food intake. Fatty acids or their metabolites can modulate neuronal activity by brain nutrient-sensing neurons involved in the regulation of energy and glucose homeostasis. The timing of three-meal schedules indicates close association with the plasma levels of insulin and preceding food availability. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition can lead to uncoupling of peripheral clocks from the central pacemaker and to the development of metabolic disorders. Metabolic dysfunction is associated with circadian disturbances at both central and peripheral levels and, eventual disruption of circadian clock functioning can lead to obesity. While CLOCK expression levels are increased with high fat diet-induced obesity, peroxisome proliferator-activated receptor (PPAR) alpha increases the transcriptional level of brain and muscle ARNT-like 1 (BMAL1) in obese subjects. Consequently, disruption of clock genes results in dyslipidemia, insulin resistance and obesity. Modifying the time of feeding alone can greatly affect body weight. Changes in the circadian clock are associated with temporal alterations in

Social memory in the rat: circadian variation and effect of circadian rhythm disruption

NARCIS (Netherlands)

Reijmers, L.G.J.E.; Leus, I.E.; Burbach, J.P.H.; Spruijt, B.M.; Ree, van J.M.

2001-01-01

Disruption of circadian rhythm can impair long-term passive avoidance memory of rats and mice. The present study investigated whether disruption of circadian rhythm can also impair social memory of male rats. Social memory was assessed using the social discrimination test, in which a short-term

Relationship between progression of visual field defect and intraocular pressure in primary open-angle glaucoma.

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Naito, Tomoko; Yoshikawa, Keiji; Mizoue, Shiro; Nanno, Mami; Kimura, Tairo; Suzumura, Hirotaka; Shiraga, Fumio

2015-01-01

To analyze the relationship between intraocular pressure (IOP) and the progression of visual field defects in Japanese primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG) patients. The subjects of the study were patients undergoing treatment for POAG or NTG who had performed visual field tests at least ten times with a Humphrey field analyzer (Swedish interactive thresholding algorithm standard, C30-2 program). The progression of visual field defects was defined by a significantly negative value of the mean deviation slope at the final visual field test during the follow-up period. The relationships between the progression of visual field defects and IOP, as well as other clinical factors, were retrospectively analyzed. A total of 156 eyes of 156 patients were included in the analysis. Significant progression of visual field defects was observed in 70 eyes of 70 patients (44.9%), while no significant progression was evident in 86 eyes of 86 patients (55.1%). The eyes with visual field defect progression had significantly lower baseline IOP (Pfield defect progression than in eyes without (Pfield defects. In NTG, IOP management should take into account not only achieving the target IOP, but also minimizing the fluctuation of IOP during follow-up period.

Comparison of sugammadex and neostigmine-atropine on intraocular pressure and postoperative effects.

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Hakimoğlu, Sedat; Tuzcu, Kasım; Davarcı, Işıl; Karcıoğlu, Murat; Ayhan Tuzcu, Esra; Hancı, Volkan; Aydın, Suzan; Kahraman, Hilal; Elbeyli, Ahmet; Turhanoğlu, Selim

2016-02-01

During surgery, changes in intraocular pressure (IOP) can be observed resulting from several factors, such as airway manipulations and drugs used. We aimed to investigate the effects of sugammadex and neostigmine on IOP, hemodynamic parameters, and complications after extubation. Our study comprised 60 patients, aged 18-65 years, with a risk status of the American Society of Anesthesiologists I-II who underwent arthroscopic surgery under general anesthesia. The patients were randomly assigned into two groups. At the end of the surgery, the neuromuscular block was reversed using neostigmine (50 μg/kg) plus atropine (15 μg/kg) in Group 1, and sugammadex (4 mg/kg) in Group 2. Neuromuscular blockade was monitored using acceleromyography and a train-of-four mode of stimulation. IOP was measured before induction and at 30 seconds, 2 minutes, and 10 minutes after extubation. A Tono-Pen XL applanation tonometer was used to measure IOP. This showed that elevation in IOP of patients reversed using sugammadex was similar to that recorded in patients reversed using neostigmine-atropine. When heart rate was compared, there was a significant difference between basal values and those obtained at 30 seconds and 10 minutes after extubation in the neostigmine-atropine group. Extubation time (time from withdrawal of anesthetic gas to extubation) was significantly shorter in the sugammadex group (p = 0.003) than in the neostigmine-atropine group. The postextubation IOP values of the sugammadex group were similar to the neostigmine-atropine group. Extubation time (time from withdrawal of anesthetic gas to extubation) was significantly shorter in the sugammadex group (p = 0.003) than in the neostigmine-atropine group. Copyright © 2016. Published by Elsevier Taiwan.

EVOLUTION THE CONCEPTS OF ROLE OF INTRAOCULAR PRESSURE IN GLAUCOMA PROGRESSION (REVIEW

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N. I. Kurysheva

2016-01-01

Full Text Available The role of elevated intraocular pressure (IOP in the progression of glaucoma optical neuropathy has emphasized repeatedly. The question about the role of elevated IOP as the underlying cause of glaucoma arose in the early 1960s. However, epidemiological studies have questioned the role of IOP as a diagnostic criterion for glaucoma, due to the relatively rare detection the disease among those with ocular hypertension and frequent detection of glaucoma with normal IOP. Multicenter studies determining the role of antihypertensive therapy in the treatment of glaucoma, have shown the importance of reducing IOP: decricing IOP at 1 mm Hg reduced the risk of developing glaucoma on 10-19%. In addition, it was found that the rate of glaucoma progression is very variable. It depends not only on the form of glaucoma, but also on other factors such as the stage of disease and therapy. Swedish study shown normal-tension glaucoma often progressed among the patients with more aggressive treatment such as argon laser trabeculoplasty or trabeculectomies. According to the study’s data, age is the most important risk factor for the progression of normal-tension glaucoma. Such questions as fluctuations in IOP, reduction of retrobulbar blood flow, antihypertensive treatment on the progression of glaucoma are still discussed. Despite the fact that the latter UKGTS multicenter study (2014 showed a decrease in the rate of progression of glaucoma in patients treated with latanoprost, a high percentage of non-treated patients didn’t have disease’s progression. In this regard, the role of IOP as main starting factor in glaucoma pathogenesis is still open.

Molecular Mechanisms of Circadian Regulation During Spaceflight

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Zanello, S. B.; Boyle, R.

2012-01-01

The physiology of both vertebrates and invertebrates follows internal rhythms coordinated in phase with the 24-hour daily light cycle. This circadian clock is governed by a central pacemaker, the suprachiasmatic nucleus (SCN) in the brain. However, peripheral circadian clocks or oscillators have been identified in most tissues. How the central and peripheral oscillators are synchronized is still being elucidated. Light is the main environmental cue that entrains the circadian clock. Under the absence of a light stimulus, the clock continues its oscillation in a free-running condition. In general, three functional compartments of the circadian clock are defined. The vertebrate retina contains endogenous clocks that control many aspects of retinal physiology, including retinal sensitivity to light, neurohormone synthesis (melatonin and dopamine), rod disk shedding, signalling pathways and gene expression. Neurons with putative local circadian rhythm generation are found among all the major neuron populations in the mammalian retina. In the mouse, clock genes and function are more localized to the inner retinal and ganglion cell layers. The photoreceptor, however, secrete melatonin which may still serve a an important circadian signal. The reception and transmission of the non-visual photic stimulus resides in a small subpopulation (1-3%) or retinal ganglion cells (RGC) that express the pigment melanopsin (Opn4) and are called intrisically photoreceptive RGC (ipRGC). Melanopsin peak absorption is at 420 nm and all the axons of the ipRGC reach the SCN. A common countermeasure for circadian re-entrainment utilizes blue-green light to entrain the circadian clock and mitigate the risk of fatigue and health and performance decrement due to circadian rhythm disruption. However, an effective countermeasure targeting the photoreceptor system requires that the basic circadian molecular machinery remains intact during spaceflight. We hypothesize that spaceflight may affect ip

Effect of hemodialysis on intraocular lens power calculation.

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Çalışkan, Sinan; Çelikay, Osman; Biçer, Tolga; Aylı, Mehmet Deniz; Gürdal, Canan

2016-01-01

To evaluate changes in ocular biometric parameters after hemodialysis (HD) in patients with end-stage renal disease (ESRD). Forty eyes of 40 patients undergoing HD were included in this cross-sectional study. Keratometry (K) readings, white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber depth (ACD), pupil diameter, lens thickness (LT), axial length (AL), and intraocular lens (IOL) power calculation were measured with Lenstar LS 900 (Haag Streit AG, Koeniz, Switzerland) before and after hemodialysis. Intraocular pressure (IOP) was measured with a non-contact tonometer (Tonopachy NT-530P, Nidek Co., LTD, Tokyo, Japan). Main outcomes were changes in biometric parameters after HD. Reliability of the measurements (intraclass correlation coefficients (ICCs)) and the effect size (Cohen's d) were also calculated. Mean difference in AL before and after HD was -0.041 ± 0.022 mm with ICCs > 0.90 (p  0.90 (p = 0.041 and Cohen's d = 0.20). Hemodialysis had no significant effect on K readings, WTW distance, CCT, ACD, LT, or IOP. Axial length and pupil diameter increase after HD with small effect size, while HD does not significantly affect IOL power calculations.

Circadian rhythm of urinary potassium excretion during treatment with an angiotensin receptor blocker.

Science.gov (United States)

Ogiyama, Yoshiaki; Miura, Toshiyuki; Watanabe, Shuichi; Fuwa, Daisuke; Tomonari, Tatsuya; Ota, Keisuke; Kato, Yoko; Ichikawa, Tadashi; Shirasawa, Yuichi; Ito, Akinori; Yoshida, Atsuhiro; Fukuda, Michio; Kimura, Genjiro

2014-12-01

We have reported that the circadian rhythm of urinary potassium excretion (U(K)V) is determined by the rhythm of urinary sodium excretion (U(Na)V) in patients with chronic kidney disease (CKD). We also reported that treatment with an angiotensin receptor blocker (ARB) increased the U(Na)V during the daytime, and restored the non-dipper blood pressure (BP) rhythm into a dipper pattern. However, the circadian rhythm of U(K)V during ARB treatment has not been reported. Circadian rhythms of U(Na)V and U(K)V were examined in 44 patients with CKD undergoing treatment with ARB. Whole-day U(Na)V was not altered by ARB whereas whole-day U(K)V decreased. Even during the ARB treatment, the significant relationship persisted between the night/day ratios of U(Na)V and U(K)V (r=0.56, pcircadian rhythm of U(K)V was determined by the rhythm of UNaV even during ARB treatment. Changes in the circadian U(K)V rhythm were not determined by aldosterone but by U(Na)V. © The Author(s) 2013.

A Case Report of Intraocular Metastasis Treated with Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Kim, Ok Bae; Byun, Sang Jun; Kim, Kwang Soo; Kim, Jin Hee [Keimyung University School of Medicine, Daegu (Korea, Republic of); Lee, Ho Jun [Daegu Catholic University School of Medicine, Daegu (Korea, Republic of)

2009-09-15

Intraocular metastasis is the most common malignancy of the eye. The frequency of intraocular metastasis in all the patients dying of cancer is about 12% and ocular metastases will be detected more frequently in the future because the patients with malignant tumor are now living longer. Intraocular metastasis can cause a serious clinical problem such as blindness. The early recognition and treatment of intraocular metastasis are very important clinical oncologic issues to maintain vision and to maximize the quality of life. However, significance of intraocular metastasis is still under-evaluated for practicing oncologists. External beam radiotherapy is a safe, effective palliative treatment in terms of preserving both the vision and the eye globe.

Circadian rhythms of women with fibromyalgia

Science.gov (United States)

Klerman, E. B.; Goldenberg, D. L.; Brown, E. N.; Maliszewski, A. M.; Adler, G. K.

2001-01-01

Fibromyalgia syndrome is a chronic and debilitating disorder characterized by widespread nonarticular musculoskeletal pain whose etiology is unknown. Many of the symptoms of this syndrome, including difficulty sleeping, fatigue, malaise, myalgias, gastrointestinal complaints, and decreased cognitive function, are similar to those observed in individuals whose circadian pacemaker is abnormally aligned with their sleep-wake schedule or with local environmental time. Abnormalities in melatonin and cortisol, two hormones whose secretion is strongly influenced by the circadian pacemaker, have been reported in women with fibromyalgia. We studied the circadian rhythms of 10 women with fibromyalgia and 12 control healthy women. The protocol controlled factors known to affect markers of the circadian system, including light levels, posture, sleep-wake state, meals, and activity. The timing of the events in the protocol were calculated relative to the habitual sleep-wake schedule of each individual subject. Under these conditions, we found no significant difference between the women with fibromyalgia and control women in the circadian amplitude or phase of rhythms of melatonin, cortisol, and core body temperature. The average circadian phases expressed in hours posthabitual bedtime for women with and without fibromyalgia were 3:43 +/- 0:19 and 3:46 +/- 0:13, respectively, for melatonin; 10:13 +/- 0:23 and 10:32 +/- 0:20, respectively for cortisol; and 5:19 +/- 0:19 and 4:57 +/- 0:33, respectively, for core body temperature phases. Both groups of women had similar circadian rhythms in self-reported alertness. Although pain and stiffness were significantly increased in women with fibromyalgia compared with healthy women, there were no circadian rhythms in either parameter. We suggest that abnormalities in circadian rhythmicity are not a primary cause of fibromyalgia or its symptoms.

Combined Acute Haemolytic and Secondary Angle Closure Glaucoma following Spontaneous Intraocular Haemorrhages in a Patient on Warfarin

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Walter Andreatta

2016-11-01

Full Text Available Background: To report the first described case of combined haemolytic and acute angle closure glaucoma secondary to spontaneous intraocular haemorrhages in a patient on excessive anticoagulation. To the best of our knowledge, this is the first case reported in the literature presenting with raised intraocular pressure due to both mechanisms. Case Description: A 90-year-old woman presented with acute pain and reduction in vision in the left eye. Her intraocular pressure (IOP was 55 mm Hg. There were red tinted blood cells in the anterior chamber giving it a reddish hue. The patient was known to have advanced wet macular degeneration. She was taking oral warfarin for atrial fibrillation. Her international normalised ratio (INR was 7.7. B-scan ultrasound of posterior segment showed vitreous and suprachoroidal haemorrhages. An ultrabiomicroscopic examination confirmed open angles. A diagnosis of haemolytic glaucoma secondary to intraocular haemorrhages was made. The IOP was controlled medically. Warfarin was withdrawn and oral vitamin K therapy was initiated leading to a rapid INR reduction. Three days later, her anterior chamber became progressively shallower causing a secondary acute angle closure which was managed medically. After 2 months, the left IOP was well-controlled without any medications and the eye was not inflamed. Her vision in that eye remained perception of light. Conclusion: Patients with suprachoroidal haemorrhages should be closely monitored as they might subsequently develop acute angle closure despite an initially open angle and well-controlled INR and IOP. Excessive anticoagulation needs to be prevented to minimise the risk of sight-threatening complications.

[Circadian markers and genes in bipolar disorder].

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Yeim, S; Boudebesse, C; Etain, B; Belliviera, F

2015-09-01

Bipolar disorder is a severe and complex multifactorial disease, characterized by alternance of acute episodes of depression and mania/hypomania, interspaced by euthymic periods. The etiological determinants of bipolar disorder yet, are still poorly understood. For the last 30 years, chronobiology is an important field of investigation to better understand the pathophysiology of bipolar disorder. We conducted a review using Medline, ISI Database, EMBase, PsyInfo up to January 2015, using the following keywords combinations: "mood disorder", "bipolar disorder", "depression", "unipolar disorder", "major depressive disorder", "affective disorder", for psychiatric conditions; and "circadian rhythms", "circadian markers", "circadian gene", "clock gene", "melatonin" for circadian rhythms. The search critera was presence of word in any field of the article. Quantitative and qualitative circadian abnormalities are associated with bipolar disorders both during acute episodes and euthymic periods, suggesting that these altered circadian rhythms may represent biological trait markers of the disorder. These circadian dysfunctions were assessed by various validated tools including polysomnography, actigraphy, sleep diaries, chronotype assessments and blood melatonin/cortisol measures. Other altered endogenous circadian activities have also been reported in bipolar patients, such as hormones secretion, core body temperature or fibroblasts activity. Moreover, these markers were also altered in healthy relatives of bipolar patients, suggesting a degree of heritability. Several genetic association studies have also showed associations between multiple circadian genes and bipolar disorder, such as CLOCK, ARTNL1, GSK3β, PER3, NPAS2, NR1D1, TIMELESS, RORA, RORB, and CSNK1ε. Thus, these circadian gene variants may contribute to the genetic susceptibility of the disease. Furthermore, the study of the clock system may help to better understand some phenotypic aspects like the

Circadian blood pressure variability in type 1 diabetes subjects and their nondiabetic siblings - influence of erythrocyte electron transfer.

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Matteucci, Elena; Consani, Cristina; Masoni, Maria Chiara; Giampietro, Ottavio

2010-10-05

Normotensive non-diabetic relatives of type 1 diabetes (T1D) patients have an abnormal blood pressure response to exercise testing that is associated with indices of metabolic syndrome and increased oxidative stress. The primary aim of this study was to investigate the circadian variability of blood pressure and the ambulatory arterial stiffness index (AASI) in healthy siblings of T1D patients vs healthy control subjects who had no first-degree relative with T1D. Secondary aims of the study were to explore the influence of both cardiovascular autonomic function and erythrocyte electron transfer activity as oxidative marker on the ambulatory blood pressure profile. Twenty-four hour ambulatory blood pressure monitoring (ABPM) was undertaken in 25 controls, 20 T1D patients and 20 siblings. In addition to laboratory examination (including homeostasis model assessment of insulin sensitivity) and clinical testing of autonomic function, we measured the rate of oxidant-induced erythrocyte electron transfer to extracellular ferricyanide (RBC vfcy). Systolic blood pressure (SBP) midline-estimating statistic of rhythm and pulse pressure were higher in T1D patients and correlated positively with diabetes duration and RBC vfcy; autonomic dysfunction was associated with diastolic BP ecphasia and increased AASI. Siblings had higher BMI, lower insulin sensitivity, larger SBP amplitude, and higher AASI than controls. Daytime SBP was positively, independently associated with BMI and RBC vfcy. Among non-diabetic people, there was a significant correlation between AASI and fasting plasma glucose. Siblings of T1D patients exhibited a cluster of sub-clinical metabolic abnormalities associated with consensual perturbations in BP variability. Moreover, our findings support, in a clinical setting, the proposed role of transplasma membrane electron transport systems in vascular pathobiology.

Circadian blood pressure variability in type 1 diabetes subjects and their nondiabetic siblings - influence of erythrocyte electron transfer

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Masoni Maria

2010-10-01

Full Text Available Abstract Background Normotensive non-diabetic relatives of type 1 diabetes (T1D patients have an abnormal blood pressure response to exercise testing that is associated with indices of metabolic syndrome and increased oxidative stress. The primary aim of this study was to investigate the circadian variability of blood pressure and the ambulatory arterial stiffness index (AASI in healthy siblings of T1D patients vs healthy control subjects who had no first-degree relative with T1D. Secondary aims of the study were to explore the influence of both cardiovascular autonomic function and erythrocyte electron transfer activity as oxidative marker on the ambulatory blood pressure profile. Methods Twenty-four hour ambulatory blood pressure monitoring (ABPM was undertaken in 25 controls, 20 T1D patients and 20 siblings. In addition to laboratory examination (including homeostasis model assessment of insulin sensitivity and clinical testing of autonomic function, we measured the rate of oxidant-induced erythrocyte electron transfer to extracellular ferricyanide (RBC vfcy. Results Systolic blood pressure (SBP midline-estimating statistic of rhythm and pulse pressure were higher in T1D patients and correlated positively with diabetes duration and RBC vfcy; autonomic dysfunction was associated with diastolic BP ecphasia and increased AASI. Siblings had higher BMI, lower insulin sensitivity, larger SBP amplitude, and higher AASI than controls. Daytime SBP was positively, independently associated with BMI and RBC vfcy. Among non-diabetic people, there was a significant correlation between AASI and fasting plasma glucose. Conclusions Siblings of T1D patients exhibited a cluster of sub-clinical metabolic abnormalities associated with consensual perturbations in BP variability. Moreover, our findings support, in a clinical setting, the proposed role of transplasma membrane electron transport systems in vascular pathobiology.

Association between urinary albumin excretion and intraocular pressure in type 2 diabetic patients without renal impairment.

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Jin A Choi

Full Text Available BACKGROUND: To assess the relationship between urinary albumin excretion and intraocular pressure (IOP in type 2 diabetes patients without renal impairment. METHODS: We explored the effects of albuminuria on high IOP in 402 non-glaucomatous type 2 diabetes without renal impairment who participated in the 2011 Korean National Health and Nutrition Examination Survey (KNHANES. Multiple logistic regression analysis was used to assess the relationship between log-transformed albumin/creatinine ratio (ACR tertiles and an IOP of ≥ 18 mmHg after adjusting for age, gender, hypertension, body mass index, triglycerides, area of residence, and education level. RESULTS: Subjects with a high IOP ≥ 18 mmHg were more likely to be current smokers (P = 0.038, heavy drinkers (P = 0.006, and to have high systolic blood pressure (P = 0.016, triglycerides (P = 0.008, and a higher log-transformed ACR (P = 0.022.In multivariate regression analysis, ACR tertile was associated with the prevalence of high IOP significantly (P = 0.022. The associations between ACR tertiles and high IOP were significant in overweight patients and those with abdominal obesity (P = 0.003 and 0.003, respectively. In contrast, there were no associations in the subgroup of patients who were not overweight and those without abdominal obesity (P = 0.291 and 0.561, respectively. CONCLUSIONS: Urinary albumin excretion is associated with high IOP in the type 2 diabetes population without renal insufficiency. The effect of the albuminuria on IOP was evident in a subgroup of patients with components of metabolic syndrome.

Circadian rhythms and reproduction.

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Boden, Michael J; Kennaway, David J

2006-09-01

There is a growing recognition that the circadian timing system, in particular recently discovered clock genes, plays a major role in a wide range of physiological systems. Microarray studies, for example, have shown that the expression of hundreds of genes changes many fold in the suprachiasmatic nucleus, liver heart and kidney. In this review, we discuss the role of circadian rhythmicity in the control of reproductive function in animals and humans. Circadian rhythms and clock genes appear to be involved in optimal reproductive performance, but there are sufficient redundancies in their function that many of the knockout mice produced do not show overt reproductive failure. Furthermore, important strain differences have emerged from the studies especially between the various Clock (Circadian Locomotor Output Cycle Kaput) mutant strains. Nevertheless, there is emerging evidence that the primary clock genes, Clock and Bmal1 (Brain and Muscle ARNT-like protein 1, also known as Mop3), strongly influence reproductive competency. The extent to which the circadian timing system affects human reproductive performance is not known, in part, because many of the appropriate studies have not been done. With the role of Clock and Bmal1 in fertility becoming clearer, it may be time to pursue the effect of polymorphisms in these genes in relation to the various types of infertility in humans.

Evolution of circadian organization in vertebrates

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M. Menaker

1997-03-01

Full Text Available Circadian organization means the way in which the entire circadian system above the cellular level is put together physically and the principles and rules that determine the interactions among its component parts which produce overt rhythms of physiology and behavior. Understanding this organization and its evolution is of practical importance as well as of basic interest. The first major problem that we face is the difficulty of making sense of the apparently great diversity that we observe in circadian organization of diverse vertebrates. Some of this diversity falls neatly into place along phylogenetic lines leading to firm generalizations: i in all vertebrates there is a "circadian axis" consisting of the retinas, the pineal gland and the suprachiasmatic nucleus (SCN, ii in many non-mammalian vertebrates of all classes (but not in any mammals the pineal gland is both a photoreceptor and a circadian oscillator, and iii in all non-mammalian vertebrates (but not in any mammals there are extraretinal (and extrapineal circadian photoreceptors. An interesting explanation of some of these facts, especially the differences between mammals and other vertebrates, can be constructed on the assumption that early in their evolution mammals passed through a "nocturnal bottleneck". On the other hand, a good deal of the diversity among the circadian systems of vertebrates does not fall neatly into place along phylogenetic lines. In the present review we will consider how we might better understand such "phylogenetically incoherent" diversity and what sorts of new information may help to further our understanding of the evolution of circadian organization in vertebrates

Accuracy of intraocular pressure measurements in dogs using two different tonometers and plano therapeutic soft contact lenses.

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Ahn, Jeong-Taek; Jeong, Man-Bok; Park, Young-Woo; Kim, Se-Eun; Ahn, Jae-Sang; Lee, Yes-Ran; Lee, Eui-Ri; Seo, Kangmoon

2012-03-01

To compare and evaluate the accuracy of intraocular pressure (IOP) measured through a therapeutic contact lens, using applanation (TonoPen XL(®)) and rebound (TonoVet(®)) tonometers in enucleated dog eyes. A total of 30 enucleated eyes from 15 beagle dogs. To measure accurate IOP, the anterior chamber of each enucleated eye was cannulated with two 26-gauge needles and two polyethylene tubes were connected vertically to an adjustable reservoir bag of normal saline and a pressure transducer. IOP was measured by the TonoPen XL(®) followed by the TonoVet(®) without a contact lens. After a contact lens was applied to the cornea, IOP was re-measured in the same order. Three consecutive IOP measurements were performed using both tonometers. Without the contact lens, the IOP values obtained by both tonometers correlated well according to the regression analysis (TonoVet(®): γ(2) = 0.98, TonoPen XL(®): γ(2) = 0.97, P contact lens was applied to the cornea. Bland-Altman analysis was used to determine the lower and upper limits of agreement (TonoVet(®): -29.7 and +21.1 mmHg, TonoPen XL(®): -3.9 and +3.6 mmHg) between the two devices. This study suggests that the TonoPen XL(®) is a useful tonometer for dogs wearing therapeutic contact lenses, and importantly, contact lenses would not need to be removed prior to IOP measurement. © 2012 American College of Veterinary Ophthalmologists.

A circadian rhythm of conidiation in Neurospora crassa (L-12)

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Miyoshi, Yashuhiro

1993-01-01

Two fungi growth chambers containing six growth tubes each are used in this experiment. One chamber is for the space experiment; the other is for the simultaneous ground control experiment. The hyphae of Neurospora crassa band A mutant are inoculated at one end of each tube. Both the chambers are kept at 3 C plus or minus 1.5 C to stop hyphae growth until the Spacelab is activated. After the activation, each chamber is transferred simultaneously to the Spacelab and a phytotron in KSC and kept in continuous light at the same temperature. After about 24 hours of light exposure, each chamber is inserted into a growth chamber bag to keep it in constant darkness. The circadian rhythm of conidiation is initiated by this light to dark transition. After the dark incubation for 5 days at room temperature, both the growth chambers are kept at 3 C plus or minus 1.5 C to stop growth of the hyphae. After the space shuttle lands, both conidiation patterns are compared and analyzed. It has been known that numerous physiological phenomena show circadian rhythms. They are characterized by the fact that the oscillation can persist under constant conditions of light and temperature. Therefore, it has been accepted by most investigators that the generation mechanism of the circadian rhythm is endogeneous. However, one cannot reject the possibility that these rhythms are caused by some geophysical exogeneous factor having a 24-hour period, such as atmospheric pressure, gravity, or electromagnetic radiation. We use Neurospora crassa band A mutual which shows an obvious circadian rhythm in its spore-forming (conidiation) on the ground, and we intend to attempt the conidation of this mutant in the Spacelab where 24-hour periodicity is severely attenuated and to elucidate the effect of the geophysical exogeneous factor in the generation mechanism of the circadian rhythm.

The Circadian Variation of Psychophysiological Reactivity to Stress : A Study of Individual Differences

Science.gov (United States)

1994-08-25

and/ or peak during the morning hours (Millar- Craig , Bishop, and Raftery, 1978; Turton and Deegan , 1974; and Weitzman et al., 1971). Furthermore, a...hematological factors showing distinct c i rcadian variations (e.g. Millar- Craig , Bishop, and Raftery, 1978; Weitzman, Fukushima, Nogeire, Roffwarg...examined the circadian variation o f blood pressure (BP), and have observed a morning peak in blood pressure (e.g., Millar- Craig , Bishop, & Raftery

Changes in intraocular pressure and anterior segment morphometry after uneventful phacoemulsification cataract surgery.

LENUS (Irish Health Repository)

Dooley, I

2012-02-01

PURPOSE: To study changes in anterior segment morphometry after uneventful phacoemulsification cataract surgery, and to investigate whether there is a relationship between any observed changes and intraocular pressure (IOP) reduction after the procedure. METHODS: The anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), central corneal thickness (CCT), and IOP were measured in 101 non-glaucomatous eyes before and after uneventful phacoemulsification cataract surgery. RESULTS: After cataract surgery, the mean ACD, ACV, and ACA values increased by 1.08 mm, 54.4 mm(3), and 13.1 degrees , respectively, and the mean IOP (corrected for CCT) decreased by 3.2 mm Hg. The predictive value of a previously described index (preoperative ACD\\/preoperative IOP (corrected for CCT) or CPD ratio) for IOP (corrected for CCT) reduction after cataract surgery was confirmed, reflected in an r(2) value of 23.3% between these two parameters (P<0.001). Other indices predictive of IOP reduction after cataract surgery were also identified, including preoperative IOP\\/preoperative ACV and preoperative IOP\\/preoperative ACA, reflected in r(2) values of 13.7 and 13.7%, respectively (P<0.001 and P<0.001, respectively). CONCLUSIONS: Our study confirms the predictive value of the CPD ratio for IOP reduction after cataract surgery, and may contribute to the decision-making process in patients with glaucoma or ocular hypertension. Furthermore, two novel indices of preoperative parameters that are predictive for IOP reduction after cataract surgery were identified, and enhance our understanding of the mechanisms underlying IOP changes after this procedure.

Assessment of Corneal Biomechanical Properties and Intraocular Pressure in Myopic Spanish Healthy Population

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María A. del Buey

2014-01-01

Full Text Available Purpose. To examine biomechanical parameters of the cornea in myopic eyes and their relationship with the degree of myopia in a western healthy population. Methods. Corneal hysteresis (CH, corneal resistance factor (CRF, Goldmann correlated intraocular pressure (IOP, and corneal compensated IOP (IOPcc were measured using the ocular response analyzer (ORA in 312 eyes of 177 Spanish subjects aged between 20 and 56 years. Refraction was expressed as spherical equivalent (SE, which ranged from 0 to −16.50 diopters (D (mean: −3.88±2.90 D. Subjects were divided into four groups according to their refractive status: group 1 or control group: emmetropia (-0.50≤SE0.05; nevertheless, IOPcc was significantly higher in the moderately myopic (15.47±2.47 mmHg and highly myopic (16.14±2.59 mmHg groups than in the emmetropia (15.15±2.06 mmHg and low myopia groups (14.53±2.37 mmHg. No correlation between age and the measured parameters was found. CH and IOPcc were weakly but significantly correlated with SE (r=0.171, P=0.002 and r=-0.131, P=0.021, resp.. Conclusions. Present study showed only a very weak, but significant, correlation between CH and refractive error, with CH being lower in both moderately and highly myopic eyes than that in the emmetropic and low myopic eyes. These changes in biomechanical properties of the cornea may have an impact on IOP measurement, increasing the risk of glaucoma.

Characterization of Intraocular Pressure Increases and Management Strategies Following Treatment With Fluocinolone Acetonide Intravitreal Implants in the FAME Trials.

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Parrish, Richard K; Campochiaro, Peter A; Pearson, P Andrew; Green, Ken; Traverso, Carlo E

2016-05-01

To compare elevated intraocular pressure (IOP) management and outcomes among patients with diabetic macular edema who received fluocinolone acetonide (FAc) implants versus sham-control treatment and explore the prior ocular steroid exposure impact on IOP outcomes. Best-corrected visual acuity (BCVA) was measured using Early Treatment Diabetic Retinopathy Study charts or electronic VA testers. Goldmann applanation tonometry was used to measure IOP. Elevated IOP was more common in FAc-versus sham control-treated patients. Medication, and less often trabeculoplasty or surgery, was used to lower IOP without affecting VA outcomes. No patient treated with 0.2 µg/day FAc who received prior ocular steroid required IOP-lowering surgery. Elevated IOP may occur following FAc implant receipt; however, in the present study, it was manageable and did not impact vision outcomes. Patients previously treated with ocular steroid did not require IOP-lowering surgery following 0.2 µg/day FAc implant administration. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:426-435.]. Copyright 2016, SLACK Incorporated.

Influence of age, circadian and homeostatic processes on inhibitory motor control: a Go/Nogo task study.

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Patricia Sagaspe

Full Text Available INTRODUCTION: The contribution of circadian system and sleep pressure influences on executive performance as a function of age has never been studied. The aim of our study was to determine the age-related evolution of inhibitory motor control (i.e., ability to suppress a prepotent motor response and sustained attention under controlled high or low sleep pressure conditions. METHODS: 14 healthy young males (mean age = 23 ± 2.7; 20-29 years and 11 healthy older males (mean age = 68 ± 1.4; 66-70 years were recruited. The volunteers were placed for 40 hours in "constant routine". In the "Sleep Deprivation SD" condition, the volunteer was kept awake for 40 hours to obtain a high sleep pressure condition interacting with the circadian process. In the "NAP" condition, the volunteer adopted a short wake/sleep cycle (150/75 min resulting in a low sleep pressure condition to counteract the homeostatic pressure and investigate the circadian process. Performances were evaluated by a simple reaction time task and a Go/Nogo task repeated every 3H45. RESULTS: In the SD condition, inhibitory motor control (i.e., ability to inhibit an inappropriate response was impaired by extended wakefulness equally in both age groups (P<.01. Sustained attention (i.e. ability to respond accurately to appropriate stimuli on the executive task decreased under sleep deprivation in both groups, and even more in young participants (P<.05. In the NAP condition, age did not influence the time course of inhibitory motor control or sustained attention. In the SD and NAP conditions, older participants had a less fluctuating reaction time performance across time of day than young participants (P<.001. CONCLUSION: Aging could be a protective factor against the effects of extended wakefulness especially on sustained attention failures due to an attenuation of sleep pressure with duration of time awake.

Piggyback intraocular lens implantation to correct pseudophakic refractive error after segmental multifocal intraocular lens implantation.

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Venter, Jan A; Oberholster, Andre; Schallhorn, Steven C; Pelouskova, Martina

2014-04-01

To evaluate refractive and visual outcomes of secondary piggyback intraocular lens implantation in patients diagnosed as having residual ametropia following segmental multifocal lens implantation. Data of 80 pseudophakic eyes with ametropia that underwent Sulcoflex aspheric 653L intraocular lens implantation (Rayner Intraocular Lenses Ltd., East Sussex, United Kingdom) to correct residual refractive error were analyzed. All eyes previously had in-the-bag zonal refractive multifocal intraocular lens implantation (Lentis Mplus MF30, models LS-312 and LS-313; Oculentis GmbH, Berlin, Germany) and required residual refractive error correction. Outcome measurements included uncorrected distance visual acuity, corrected distance visual acuity, uncorrected near visual acuity, distance-corrected near visual acuity, manifest refraction, and complications. One-year data are presented in this study. The mean spherical equivalent ranged from -1.75 to +3.25 diopters (D) preoperatively (mean: +0.58 ± 1.15 D) and reduced to -1.25 to +0.50 D (mean: -0.14 ± 0.28 D; P < .01). Postoperatively, 93.8% of eyes were within ±0.50 D and 98.8% were within ±1.00 D of emmetropia. The mean uncorrected distance visual acuity improved significantly from 0.28 ± 0.16 to 0.01 ± 0.10 logMAR and 78.8% of eyes achieved 6/6 (Snellen 20/20) or better postoperatively. The mean uncorrected near visual acuity changed from 0.43 ± 0.28 to 0.19 ± 0.15 logMAR. There was no significant change in corrected distance visual acuity or distance-corrected near visual acuity. No serious intraoperative or postoperative complications requiring secondary intraocular lens removal occurred. Sulcoflex lenses proved to be a predictable and safe option for correcting residual refractive error in patients diagnosed as having pseudophakia. Copyright 2014, SLACK Incorporated.

Comparison between Betamethasone, Fluorometholone and Loteprednol Etabonate on intraocular pressure in patients after keratorefractive surgery

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Saeed Shokoohi-Rad

2018-06-01

Full Text Available Purpose: The aim of this study was to compare the ocular hypertensive effect of the commercially available Betamethasone, Fluorometholone in Iran and Loteprednol Etabonate in patients undergoing keratorefractive surgery. Methods: In this prospective randomized clinical trial, 300 eyes of 150 patients were included, and patients were randomly assigned to 3 groups and used one of the 3 steroid drops (Betamethasone 0.1%, Fluorometholone 0.1%, and Loteprednol Etabonate 0.5% after myopic photorefractive keratectomy (PRK. Intraocular pressure (IOP was measured 2, 4, and 6 weeks post-surgery. Twenty-two mmHg was set as the threshold IOP for starting anti-glaucoma medication and tapering steroid drops. Results: Of 300 eyes from 150 patients over the first 6 postoperative weeks, 2 eyes in Fluorometholone group (2%, 12 eyes in Betamethasone group (12%, and 16 eyes in Loteprednol group (16% had IOP equal or more than 22 mmHg. Analysis of variance (ANOVA test showed that the rise in IOP was significantly different between groups in the 2nd and 4th (P ≤ 0.001 postoperative weeks but not at 6th week (P = 0.230. An IOP rise equal or more than 10 mmHg was detected in 13 and 15 eyes in Betamethasone and Loteprednol groups, respectively. None of the eyes in Fluorometholone group had such an IOP rise. Conclusions: Loteprednol and Fluorometholone were associated with the most and least increase in IOP, respectively. The highest pressures were detected 4 weeks after surgery in the Betamethasone and Loteprednol groups and 6 weeks after surgery in the Fluorometholone group. Fluorometholone was the safest among the three examined steroid drops in terms of IOP rise. Keywords: Steroid induced glaucoma, Loteprednol etabonate, Keratorefractive surgery, Photorefractive keratectomy

Allometry and Scaling of the Intraocular Pressure and Aqueous Humour Flow Rate in Vertebrate Eyes

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Zouache, Moussa A.; Eames, Ian; Samsudin, Amir

2016-01-01

In vertebrates, intraocular pressure (IOP) is required to maintain the eye into a shape allowing it to function as an optical instrument. It is sustained by the balance between the production of aqueous humour by the ciliary body and the resistance to its outflow from the eye. Dysregulation of the IOP is often pathological to vision. High IOP may lead to glaucoma, which is in man the second most prevalent cause of blindness. Here, we examine the importance of the IOP and rate of formation of aqueous humour in the development of vertebrate eyes by performing allometric and scaling analyses of the forces acting on the eye during head movement and the energy demands of the cornea, and testing the predictions of the models against a list of measurements in vertebrates collated through a systematic review. We show that the IOP has a weak dependence on body mass, and that in order to maintain the focal length of the eye, it needs to be an order of magnitude greater than the pressure drop across the eye resulting from gravity or head movement. This constitutes an evolutionary constraint that is common to all vertebrates. In animals with cornea-based optics, this constraint also represents a condition to maintain visual acuity. Estimated IOPs were found to increase with the evolution of terrestrial animals. The rate of formation of aqueous humour was found to be adjusted to the metabolic requirements of the cornea, scaling as Vac0.67, where Vac is the volume of the anterior chamber. The present work highlights an interdependence between IOP and aqueous flow rate crucial to ocular function that must be considered to understand the evolution of the dioptric apparatus. It should also be taken into consideration in the prevention and treatment of glaucoma. PMID:26990431

Regulation of reproduction by the circadian rhythms.

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Zhang, Wen-Xiang; Chen, Si-Yu; Liu, Chang

2016-12-25

Mammals synchronize their circadian activity primarily to the cycles of light and darkness in the environment. Circadian rhythm is controlled by the central clock in the hypothalamic suprachiasmatic nucleus (SCN) and the peripheral clocks in various tissues. More importantly, the central clock can integrate photic/nonphotic signals to generate rhythmic outputs, and then drive the slave oscillators in peripheral tissues through neuroendocrine and behavioral signals. Human reproductive activities, as some other physiological functions, are controlled by the biological clocks. Accumulating lines of epidemiological and genetic evidence indicate that disruption of circadian clock can be directly involved in multiple pathological processes, including infertility. In this review, we mainly discuss the presence of a circadian clock in reproductive tissues and its roles in follicles development, ovulation, spermatogenesis, fertilization and embryo implantation, etc. As the increased shift work and assisted reproductive technologies possibly disrupt circadian rhythmicity to impact reproduction, the importance of circadian rhythms should be highlighted in the regulation of reproductive process.

Comparison of sugammadex and neostigmine–atropine on intraocular pressure and postoperative effects

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Sedat Hakimoğlu

2016-02-01

Full Text Available During surgery, changes in intraocular pressure (IOP can be observed resulting from several factors, such as airway manipulations and drugs used. We aimed to investigate the effects of sugammadex and neostigmine on IOP, hemodynamic parameters, and complications after extubation. Our study comprised 60 patients, aged 18–65 years, with a risk status of the American Society of Anesthesiologists I–II who underwent arthroscopic surgery under general anesthesia. The patients were randomly assigned into two groups. At the end of the surgery, the neuromuscular block was reversed using neostigmine (50 μg/kg plus atropine (15 μg/kg in Group 1, and sugammadex (4 mg/kg in Group 2. Neuromuscular blockade was monitored using acceleromyography and a train-of-four mode of stimulation. IOP was measured before induction and at 30 seconds, 2 minutes, and 10 minutes after extubation. A Tono-Pen XL applanation tonometer was used to measure IOP. This showed that elevation in IOP of patients reversed using sugammadex was similar to that recorded in patients reversed using neostigmine–atropine. When heart rate was compared, there was a significant difference between basal values and those obtained at 30 seconds and 10 minutes after extubation in the neostigmine–atropine group. Extubation time (time from withdrawal of anesthetic gas to extubation was significantly shorter in the sugammadex group (p = 0.003 than in the neostigmine–atropine group. The postextubation IOP values of the sugammadex group were similar to the neostigmine–atropine group. Extubation time (time from withdrawal of anesthetic gas to extubation was significantly shorter in the sugammadex group (p = 0.003 than in the neostigmine–atropine group.

Comparison of the Effect of Atracurium and Cisatracurium on Intraocular Pressure and Pupillary Diameter

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Mansoor Masjedi

2013-10-01

Full Text Available Purpose: Although there are ample evidences for the effects (mostly decrease of intraocular pressure (IOP after the administration of atracurium and cisatracurium during general anesthesia in ophthalmic operations, no study has yet been done to compare their effects on both IOP and pupillary diameter (PD simultaneously. The aim of this study was to determine whether there is any difference between the effects of atracurium and cisatracurium on IOP and PD.Methods: Sixty patients with American Society of Anesthesiologists class I-II without history of previous eye surgery were studied in two randomly divided, double-blind groups. Following induction of anesthesia, atracurium (0.6 mg/kg and cisatracurium (0.15 mg/kg were administered to each group. IOP was measured by applanation tonometry (TONO – PEN ® XL and PD (COLVARD pupillometer at six sequential occasions, before induction of anesthesia, 2 and 5 minutes after induction and 2, 5 and 10 minutes after intubation prior to initiation of operation. Then they were compared to each other.Results: Trend of recorded IOP and PD values showed that there were no statistically significant differences between atracurium and cisatracurium according to their effect on IOP (p=0.125 and PD (p>0.137 during the course of study. Conclusion: It seems that both atracurium and cisatracurium have similar effects on IOP and PD before and up to ten minutes after tracheal intubation prior to surgical intervention.

Circadian Pacemaker – Temperature Compensation

NARCIS (Netherlands)

Gerkema, Menno P.; Binder, Marc D.; Hirokawa, Nobutaka; Windhorst, Uwe

2009-01-01

One of the defining characteristics of circadian pacemakers and indicates the independence of the speed of circadian clock processes of environmental temperature. Mechanisms involved, so far not elucidated in full detail, entail at least two processes that are similarly affected by temperature

A New Perspective for Parkinson's Disease: Circadian Rhythm.

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Li, Siyue; Wang, Yali; Wang, Fen; Hu, Li-Fang; Liu, Chun-Feng

2017-02-01

Circadian rhythm is manifested by the behavioral and physiological changes from day to night, which is controlled by the pacemaker and its regulator. The former is located at the suprachiasmatic nuclei (SCN) in the anterior hypothalamus, while the latter is composed of clock genes present in all tissues. Circadian desynchronization influences normal patterns of day-night rhythms such as sleep and alertness cycles, rest and activity cycles. Parkinson's disease (PD) exhibits diurnal fluctuations. Circadian dysfunction has been observed in PD patients and animal models, which may result in negative consequences to the homeostasis and even exacerbate the disease progression. Therefore, circadian therapies, including light stimulation, physical activity, dietary and social schedules, may be helpful for PD patients. However, the cellular and molecular mechanisms that underlie the circadian dysfunction in PD remain elusive. Further research on circadian patterns is needed. This article summarizes the existing research on the circadian rhythms in PD, focusing on the clinical symptom variations, molecular changes, as well as the available treatment options.

Nocturia: The circadian voiding disorder

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Jin Wook Kim

2016-05-01

Full Text Available Nocturia is a prevalent condition of waking to void during the night. The concept of nocturia has evolved from being a symptomatic aspect of disease associated with the prostate or bladder to a form of lower urinary tract disorder. However, recent advances in circadian biology and sleep science suggest that it might be important to consider nocturia as a form of circadian dysfunction. In the current review, nocturia is reexamined with an introduction to sleep disorders and recent findings in circadian biology in an attempt to highlight the importance of rediscovering nocturia as a problem of chronobiology.

Identification of circadian clock modulators from existing drugs.

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Tamai, T Katherine; Nakane, Yusuke; Ota, Wataru; Kobayashi, Akane; Ishiguro, Masateru; Kadofusa, Naoya; Ikegami, Keisuke; Yagita, Kazuhiro; Shigeyoshi, Yasufumi; Sudo, Masaki; Nishiwaki-Ohkawa, Taeko; Sato, Ayato; Yoshimura, Takashi

2018-04-17

Chronic circadian disruption due to shift work or frequent travel across time zones leads to jet-lag and an increased risk of diabetes, cardiovascular disease, and cancer. The development of new pharmaceuticals to treat circadian disorders, however, is costly and hugely time-consuming. We therefore performed a high-throughput chemical screen of existing drugs for circadian clock modulators in human U2OS cells, with the aim of repurposing known bioactive compounds. Approximately 5% of the drugs screened altered circadian period, including the period-shortening compound dehydroepiandrosterone (DHEA; also known as prasterone). DHEA is one of the most abundant circulating steroid hormones in humans and is available as a dietary supplement in the USA Dietary administration of DHEA to mice shortened free-running circadian period and accelerated re-entrainment to advanced light-dark (LD) cycles, thereby reducing jet-lag. Our drug screen also revealed the involvement of tyrosine kinases, ABL1 and ABL2, and the BCR serine/threonine kinase in regulating circadian period. Thus, drug repurposing is a useful approach to identify new circadian clock modulators and potential therapies for circadian disorders. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

Age-Related Changes of Intraocular Pressure in Elderly People in Southern China: Lingtou Eye Cohort Study.

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Xiaotong Han

Full Text Available To study age-related changes of intraocular pressure (IOP and assess the cohort effect in both cross-sectional and longitudinal settings among elderly Chinese adults.Participants were enrolled from the Lingtou Eye Cohort Study with Chinese government officials aged 40 years and older at baseline and received physical check-up and ocular examinations from 2010 to 2012. IOP was measured using a non-contact tonometer according to standardized protocols, as well as systolic blood pressure (SBP, diastolic blood pressure (DBP and body mass index (BMI. Participants who had attended IOP measurements in both 2010 and 2012 were included in this study. Cross-sectional association of IOP with age was assessed using multivariate liner regression analyses and based on the data of 2010. Longitudinal changes in IOP were assessed by paired t-test.A total of 3372 subjects were enrolled in the current analysis (2010 mean [SD] age, 61.9 [7.1] years; 60.2% men. The mean IOP in 2010 was 15.4 ± 2.3 mmHg for women and 15.2 ± 2.3 mmHg for men with an intersex difference (P = 0.029. Cross-sectional analysis showed that IOP was negatively associated with age (P = 0.003, β = -0.033 for women and P<0.001, β = -0.061 for men adjusted for baseline SBP, DBP and BMI. Paired t-test suggested that IOP was higher in the year 2012 than 2010 in women (P = 0.006 but did not change significantly in men within 2 years (P = 0.345. In addition, the 2-year changes of IOP were not associated with age adjusted for baseline IOP in 2010 (P = 0.249.Cross-sectional data suggests that IOP is lower in people with older age. Longitudinal data does not support such findings and thus the identified decreasing pattern with age in cross-sectional analysis is likely caused by cohort effects.

Review and update of intraocular therapy in noninfectious uveitis.

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Sallam, Ahmed; Taylor, Simon R J; Lightman, Sue

2011-11-01

To review new clinically relevant data regarding the intraocular treatment of noninfectious uveitis. Triamcinolone acetonide, the most commonly used intravitreal corticosteroid for treatment of uveitis and uveitic macular oedema has a limited duration of action and is associated with a high risk of corticosteroid-induced intraocular pressure (IOP) rise and cataract. Recent advances have led to the development of sustained-release corticosteroid devices using different corticosteroids such as dexamethasone and fluocinolone acetonide. Treatment options for patients who have previously exhibited corticosteroid hypertensive response have also expanded through the use of new noncorticosteroid intravitreal therapeutics such as methotrexate and antivascular endothelial growth factor (anti-VEGF) agents. Ozurdex dexamethasone implant appears to have a better safety profile, and a slightly long-lasting effect than triamcinolone acetonide. The Retisert implant allows the release of corticosteroids at a constant rate for 2.5 years, but it requires surgical placement and its use is associated with a very high risk of cataract and requirement for IOP-lowering surgery. For patients who are steroid responders, methotrexate may offer a better alternative to corticosteroid treatment than anti-VEGF agents, but controlled trials are required to confirm this.

21 CFR 886.4300 - Intraocular lens guide.

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2010-04-01

...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4300 Intraocular lens guide. (a) Identification. An intraocular lens guide is a device intended to be inserted into the eye during surgery to direct... lenses, the device is exempt from the premarket notification procedures in subpart E of part 807 of this...

Ischemic stroke destabilizes circadian rhythms

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Borjigin Jimo

2008-10-01

Full Text Available Abstract Background The central circadian pacemaker is a remarkably robust regulator of daily rhythmic variations of cardiovascular, endocrine, and neural physiology. Environmental lighting conditions are powerful modulators of circadian rhythms, but regulation of circadian rhythms by disease states is less clear. Here, we examine the effect of ischemic stroke on circadian rhythms in rats using high-resolution pineal microdialysis. Methods Rats were housed in LD 12:12 h conditions and monitored by pineal microdialysis to determine baseline melatonin timing profiles. After demonstration that the circadian expression of melatonin was at steady state, rats were subjected to experimental stroke using two-hour intralumenal filament occlusion of the middle cerebral artery. The animals were returned to their cages, and melatonin monitoring was resumed. The timing of onset, offset, and duration of melatonin secretion were calculated before and after stroke to determine changes in circadian rhythms of melatonin secretion. At the end of the monitoring period, brains were analyzed to determine infarct volume. Results Rats demonstrated immediate shifts in melatonin timing after stroke. We observed a broad range of perturbations in melatonin timing in subsequent days, with rats exhibiting onset/offset patterns which included: advance/advance, advance/delay, delay/advance, and delay/delay. Melatonin rhythms displayed prolonged instability several days after stroke, with a majority of rats showing a day-to-day alternation between advance and delay in melatonin onset and duration. Duration of melatonin secretion changed in response to stroke, and this change was strongly determined by the shift in melatonin onset time. There was no correlation between infarct size and the direction or amplitude of melatonin phase shifting. Conclusion This is the first demonstration that stroke induces immediate changes in the timing of pineal melatonin secretion, indicating

Linking Core Promoter Classes to Circadian Transcription.

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Pål O Westermark

2016-08-01

Full Text Available Circadian rhythms in transcription are generated by rhythmic abundances and DNA binding activities of transcription factors. Propagation of rhythms to transcriptional initiation involves the core promoter, its chromatin state, and the basal transcription machinery. Here, I characterize core promoters and chromatin states of genes transcribed in a circadian manner in mouse liver and in Drosophila. It is shown that the core promoter is a critical determinant of circadian mRNA expression in both species. A distinct core promoter class, strong circadian promoters (SCPs, is identified in mouse liver but not Drosophila. SCPs are defined by specific core promoter features, and are shown to drive circadian transcriptional activities with both high averages and high amplitudes. Data analysis and mathematical modeling further provided evidence for rhythmic regulation of both polymerase II recruitment and pause release at SCPs. The analysis provides a comprehensive and systematic view of core promoters and their link to circadian mRNA expression in mouse and Drosophila, and thus reveals a crucial role for the core promoter in regulated, dynamic transcription.

Coordination of the maize transcriptome by a conserved circadian clock

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Harmon Frank G

2010-06-01

Full Text Available Abstract Background The plant circadian clock orchestrates 24-hour rhythms in internal physiological processes to coordinate these activities with daily and seasonal changes in the environment. The circadian clock has a profound impact on many aspects of plant growth and development, including biomass accumulation and flowering time. Despite recent advances in understanding the circadian system of the model plant Arabidopsis thaliana, the contribution of the circadian oscillator to important agronomic traits in Zea mays and other cereals remains poorly defined. To address this deficit, this study investigated the transcriptional landscape of the maize circadian system. Results Since transcriptional regulation is a fundamental aspect of circadian systems, genes exhibiting circadian expression were identified in the sequenced maize inbred B73. Of the over 13,000 transcripts examined, approximately 10 percent displayed circadian expression patterns. The majority of cycling genes had peak expression at subjective dawn and dusk, similar to other plant circadian systems. The maize circadian clock organized co-regulation of genes participating in fundamental physiological processes, including photosynthesis, carbohydrate metabolism, cell wall biogenesis, and phytohormone biosynthesis pathways. Conclusions Circadian regulation of the maize genome was widespread and key genes in several major metabolic pathways had circadian expression waveforms. The maize circadian clock coordinated transcription to be coincident with oncoming day or night, which was consistent with the circadian oscillator acting to prepare the plant for these major recurring environmental changes. These findings highlighted the multiple processes in maize plants under circadian regulation and, as a result, provided insight into the important contribution this regulatory system makes to agronomic traits in maize and potentially other C4 plant species.

Intraocular pressure measurement over soft contact lens by rebound tonometer:a comparative study

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Senay Asik Nacaroglu

2015-06-01

Full Text Available AIM: To evaluate the intraocular pressure (IOP measurements by Icare rebound tonometer over a contact lens in comparison with Goldmann applanation tonometry (GAT.METHODS: Fifty patients using contact lens were included in this study. One of the eyes of the patients was selected randomly and their IOP were measured by rebound tonometer with and without contact lens (RTCL, RT respectively and by GAT, as well as their central corneal thickness (CCT by optical pachymeter. The results of both methods were compared by correlation analysis, general linear method repeated measure and Bland-Altman analysis.RESULTS: Mean IOP values measured by RTCL, RT and GAT were 15.68±3.7, 14.50±3.4 and 14.16±2.8 (P<0.001, respectively. Mean IOP by RTCL was significantly higher than the measurements implemented by RT and GAT (P<0.001, while there was no difference between the measurements by GAT and RT (P=0.629. There was a good level of positive correlation between GAT and RTCL as well as RT (r=0.786 P<0.001, r=0.833 P<0.001, respectively. We have observed that CCT increase did not show any correlation with the differences of the measurements between RTCL and RT (P=0.329, RTCL and GAT (P=0.07 as well as RT and GAT (P=0.189 in linear regression model.CONCLUSION: The average of the measurements over contact lens by rebound tonometer was found to be higher than what was measured by GAT. Although this difference is statistically significant, it may be clinically negligible in the normal population.

Haploinsufficient Bmp4 ocular phenotypes include anterior segment dysgenesis with elevated intraocular pressure

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Nusinowitz Steven

2001-11-01

Full Text Available Abstract Background Glaucoma is a blinding disease usually associated with high intraocular pressure (IOP. In some families, abnormal anterior segment development contributes to glaucoma. The genes causing anterior segment dysgenesis and glaucoma in most of these families are not identified and the affected developmental processes are poorly understood. Bone morphogenetic proteins (BMPs participate in various developmental processes. We tested the importance of Bmp4 gene dosage for ocular development and developmental glaucoma. Results Bmp4+/- mice have anterior segment abnormalities including malformed, absent or blocked trabecular meshwork and Schlemm's canal drainage structures. Mice with severe drainage structure abnormalities, over 80% or more of their angle's extent, have elevated IOP. The penetrance and severity of abnormalities is strongly influenced by genetic background, being most severe on the C57BL/6J background and absent on some other backgrounds. On the C57BL/6J background there is also persistence of the hyaloid vasculature, diminished numbers of inner retinal cells, and absence of the optic nerve. Conclusions We demonstrate that heterozygous deficiency of BMP4 results in anterior segment dysgenesis and elevated IOP. The abnormalities are similar to those in human patients with developmental glaucoma. Thus, BMP4 is a strong candidate to contribute to Axenfeld-Rieger anomaly and other developmental conditions associated with human glaucoma. BMP4 also participates in posterior segment development and wild-type levels are usually critical for optic nerve development on the C57BL/6J background. Bmp4+/- mice are useful for studying various components of ocular development, and may allow identification of strain specific modifiers affecting a variety of ocular phenotypes.

Mice deficient of glutamatergic signaling from intrinsically photosensitive retinal ganglion cells exhibit abnormal circadian photoentrainment.

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Nicole Purrier

Full Text Available Several aspects of behavior and physiology, such as sleep and wakefulness, blood pressure, body temperature, and hormone secretion exhibit daily oscillations known as circadian rhythms. These circadian rhythms are orchestrated by an intrinsic biological clock in the suprachiasmatic nuclei (SCN of the hypothalamus which is adjusted to the daily environmental cycles of day and night by the process of photoentrainment. In mammals, the neuronal signal for photoentrainment arises from a small subset of intrinsically photosensitive retinal ganglion cells (ipRGCs that send a direct projection to the SCN. ipRGCs also mediate other non-image-forming (NIF visual responses such as negative masking of locomotor activity by light, and the pupillary light reflex (PLR via co-release of neurotransmitters glutamate and pituitary adenylate cyclase-activating peptide (PACAP from their synaptic terminals. The relative contribution of each neurotransmitter system for the circadian photoentrainment and other NIF visual responses is still unresolved. We investigated the role of glutamatergic neurotransmission for circadian photoentrainment and NIF behaviors by selective ablation of ipRGC glutamatergic synaptic transmission in mice. Mutant mice displayed delayed re-entrainment to a 6 h phase shift (advance or delay in the light cycle and incomplete photoentrainment in a symmetrical skeleton photoperiod regimen (1 h light pulses between 11 h dark periods. Circadian rhythmicity in constant darkness also was reduced in some mutant mice. Other NIF responses such as the PLR and negative masking responses to light were also partially attenuated. Overall, these results suggest that glutamate from ipRGCs drives circadian photoentrainment and negative masking responses to light.

Short-Wavelength Countermeasures for Circadian Desynchrony

National Research Council Canada - National Science Library

Heller, H. C; Smith, Mark

2008-01-01

.... Exposure of humans to bright light for an hour or more at the right phase of the circadian cycle produces significant phase shifts of circadian rhythms speeding recovery from jet-lag, and optimizing...

NONO couples the circadian clock to the cell cycle.

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Kowalska, Elzbieta; Ripperger, Juergen A; Hoegger, Dominik C; Bruegger, Pascal; Buch, Thorsten; Birchler, Thomas; Mueller, Anke; Albrecht, Urs; Contaldo, Claudio; Brown, Steven A

2013-01-29

Mammalian circadian clocks restrict cell proliferation to defined time windows, but the mechanism and consequences of this interrelationship are not fully understood. Previously we identified the multifunctional nuclear protein NONO as a partner of circadian PERIOD (PER) proteins. Here we show that it also conveys circadian gating to the cell cycle, a connection surprisingly important for wound healing in mice. Specifically, although fibroblasts from NONO-deficient mice showed approximately normal circadian cycles, they displayed elevated cell doubling and lower cellular senescence. At a molecular level, NONO bound to the p16-Ink4A cell cycle checkpoint gene and potentiated its circadian activation in a PER protein-dependent fashion. Loss of either NONO or PER abolished this activation and circadian expression of p16-Ink4A and eliminated circadian cell cycle gating. In vivo, lack of NONO resulted in defective wound repair. Because wound healing defects were also seen in multiple circadian clock-deficient mouse lines, our results therefore suggest that coupling of the cell cycle to the circadian clock via NONO may be useful to segregate in temporal fashion cell proliferation from tissue organization.

DESIGN OF THE MULTIORDER INTRAOCULAR LENSES

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V. G. Kolobrodov

2015-01-01

Full Text Available Intraocular lenses (IOLs are used to replace the natural crystalline lens of the eye. Just few basic designs of IOLs are used clinically. Multiorder diffractive lenses (MODL which operate simultaneously in several diffractive orders were proposed to decrease the chromatic aberration. Properties analysis of MODL showed a possibility to use them to develop new designs of IOLs. The purpose of this paper was to develop a new method of designing of multiorder intraocular lenses with decreased chromatic aberration. The theoretical research of the lens properties was carried out. The diffraction efficiency dependence with the change of wavelength was studied. A computer simulation of MODL in a schematic model of the human eye was carried out. It is found the capability of the multiorder diffractive lenses to focus polychromatic light into a segment on the optical axis with high diffraction efficiency. At each point of the segment is present each component of the spectral range, which will build a color image in combination. The paper describes the new design method of intraocular lenses with reduced chromaticism and with endless adaptation. An optical system of an eye with an intraocular lens that provides sharp vision of objects located at a distance of 700 mm to infinity is modeled.

Circadian Rhythm Sleep-Wake Disorders in Older Adults.

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Kim, Jee Hyun; Duffy, Jeanne F

2018-03-01

The timing, duration, and consolidation of sleep result from the interaction of the circadian timing system with a sleep-wake homeostatic process. When aligned and functioning optimally, this allows wakefulness throughout the day and a long consolidated sleep episode at night. Mismatch between the desired timing of sleep and the ability to fall and remain asleep is a hallmark of the circadian rhythm sleep-wake disorders. This article discusses changes in circadian regulation of sleep with aging; how age influences the prevalence, diagnosis, and treatment of circadian rhythm sleep-wake disorders; and how neurologic diseases in older patients affect circadian rhythms and sleep. Copyright © 2017 Elsevier Inc. All rights reserved.

Lente intra-ocular multifocal difrativa apodizada: resultados Diffractive apodized multifocal intraocular lens: results

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Virgilio Centurion

2007-12-01

Full Text Available OBJETIVO: Mostrar os resultados visuais e refracionais com lente intra-ocular multifocal difrativa apodizada. MÉTODOS: Estudo de 100 olhos de 50 pacientes com catarata, submetidos à facoemulsificação com implante bilateral de lente intra-ocular (LIO multifocal difrativa apodizada. Foi avaliada a acuidade visual binocular sem e com correção para longe e perto, a previsibilidade refracional e a freqüência de uso de óculos. RESULTADOS: A acuidade visual sem correção para longe foi de e " 20/30 em 97,56% dos olhos operados e e" J2 em 100%, sendo que 82% dos pacientes nunca usam óculos e 16% usam de forma esporádica. CONCLUSÃO: A LIO multifocal difrativa apodizada mostrou ser uma opção previsível, reproduzível e segura na correção dos vícios de refração para longe e perto durante a cirurgia da catarata, permitindo elevado índice de independência ao uso de óculos.OBJECTIVE: To show visual and refraction results using multifocal diffractive apodized intraocular lens. METHODS: The study of 100 eyes of 50 patients with cataract, submitted to phacoemulsification with bilateral implant of multifocal diffractive apodized intraocular lens (IOL. Binocular visual acuity was evaluated with and without correction for near and distance, and refraction previsibility and frequency of wearing glasses. RESULTS: Visual acuity without correction for distance was e" 20/30 in 97.56% of eyes operated on and e" J2 in 100%, of these 82% of patients never wear glasses and 16% wear glasses sporadically. CONCLUSION: Multifocal diffractive apodized IOL proved to be a foreseeable option, reproducible and safe in the correction of refraction errors for distance and near during cataract surgery, enabling a high rate of independence from the use of glasses.

Review of the influence of pigment dispersion and exfoliation glaucoma diagnosis on intraocular pressure in clinical trials evaluating primary open-angle glaucoma and ocular hypertension.

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Stewart, William C; DeMill, D L; Wirostko, Barbara M; Nelson, Lindsay A; Stewart, Jeanette A

2013-08-01

To evaluate published, randomized, prospective, parallel clinical trials utilizing currently approved glaucoma medications to determine what influence, if any, pigment dispersion (PD) or exfoliation glaucoma (XFG) patients had on the intraocular pressure. A review of clinical trial articles evaluating currently used topical glaucoma medicines. Articles were published between January 1995 and April 2011. If the articles met the inclusion/exclusion criteria, they were analyzed for PD and XFG. Twenty-four articles were included, containing 49 treatment arms that included PD or XFG patients. The range of PD patients was 0% to 4.5%, with a mean of 1.5±0.9%, and for XFG patients 0% to 6.3%, with a mean of 2.2±2.1%. The treatment arms with PD showed a difference in the intraocular pressures (IOPs), for all studies analyzed together, for the baseline IOPs between clinical trials that did and did not include PD patients (8 AM IOPs: with PD 26.5±0.9 mm Hg and without PD 25.8±1.3 mm Hg, P=0.024; and diurnal curve mean IOPs: with PD 25.3±1.1 mm Hg and without PD 24.5±1.3 mm Hg, P=0.024). The XFG treatment arms showed that there was a difference in the IOPs for all studies analyzed together for diurnal baseline IOPs between clinical trials that did and did not include XFG patients (with XFG 25.2±1.2 mm Hg and without XFG 24.3±1.0 mm Hg, P=0.016). Trial designs for prospective, parallel, glaucoma clinical studies that are performed in the United States generally can include PD and XFG patients with only a small impact on the IOP and a low number of such subjects enrolled.

Implications of Circadian Rhythm in Dopamine and Mood Regulation.

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Kim, Jeongah; Jang, Sangwon; Choe, Han Kyoung; Chung, Sooyoung; Son, Gi Hoon; Kim, Kyungjin

2017-07-31

Mammalian physiology and behavior are regulated by an internal time-keeping system, referred to as circadian rhythm. The circadian timing system has a hierarchical organization composed of the master clock in the suprachiasmatic nucleus (SCN) and local clocks in extra-SCN brain regions and peripheral organs. The circadian clock molecular mechanism involves a network of transcription-translation feedback loops. In addition to the clinical association between circadian rhythm disruption and mood disorders, recent studies have suggested a molecular link between mood regulation and circadian rhythm. Specifically, genetic deletion of the circadian nuclear receptor Rev-erbα induces mania-like behavior caused by increased midbrain dopaminergic (DAergic) tone at dusk. The association between circadian rhythm and emotion-related behaviors can be applied to pathological conditions, including neurodegenerative diseases. In Parkinson's disease (PD), DAergic neurons in the substantia nigra pars compacta progressively degenerate leading to motor dysfunction. Patients with PD also exhibit non-motor symptoms, including sleep disorder and neuropsychiatric disorders. Thus, it is important to understand the mechanisms that link the molecular circadian clock and brain machinery in the regulation of emotional behaviors and related midbrain DAergic neuronal circuits in healthy and pathological states. This review summarizes the current literature regarding the association between circadian rhythm and mood regulation from a chronobiological perspective, and may provide insight into therapeutic approaches to target psychiatric symptoms in neurodegenerative diseases involving circadian rhythm dysfunction.

Circadian expression profiles of chromatin remodeling factor genes in Arabidopsis.

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Lee, Hong Gil; Lee, Kyounghee; Jang, Kiyoung; Seo, Pil Joon

2015-01-01

The circadian clock is a biological time keeper mechanism that regulates biological rhythms to a period of approximately 24 h. The circadian clock enables organisms to anticipate environmental cycles and coordinates internal cellular physiology with external environmental cues. In plants, correct matching of the clock with the environment confers fitness advantages to plant survival and reproduction. Therefore, circadian clock components are regulated at multiple layers to fine-tune the circadian oscillation. Epigenetic regulation provides an additional layer of circadian control. However, little is known about which chromatin remodeling factors are responsible for circadian control. In this work, we analyzed circadian expression of 109 chromatin remodeling factor genes and identified 17 genes that display circadian oscillation. In addition, we also found that a candidate interacts with a core clock component, supporting that clock activity is regulated in part by chromatin modification. As an initial attempt to elucidate the relationship between chromatin modification and circadian oscillation, we identified novel regulatory candidates that provide a platform for future investigations of chromatin regulation of the circadian clock.

Measurements of intraocular pressure by Goldmann tonometry, Tonopen XL, and the transpalpebral tonometer, TGDc-01, after penetrating keratoplasty: a comparativye study.

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Shemesh, Gabi; Waisbourd, Michael; Varssano, David; Michaeli, Adi; Lazar, Moshe; Kurtz, Shimon

2009-08-01

The aim of this study was to compare intraocular pressure (IOP) measurements obtained by Goldmann tonometry (GT), the Tonopen XL, and a new transpalpebral tonometer, TGDc-01, in eyes that had undergone penetrating keratoplasty (PKP). IOP was measured in post-PKP eyes by means of GT, Tonopen XL, and TGDc-01. Central corneal thickness measurements were also obtained for all eyes. Forty-five eyes of 43 patients were enrolled in the study. The mean IOP difference (+/-SD) was -0.42 +/- 5.83 mm Hg between GT and Tonopen and 3.20 +/- 7.55 mm Hg between GT and TGDc-01. The correlation coefficient was 0.84 between GT and Tonopen XL (P tonometer is simply inaccurate or whether avoiding contact with the corneal graft by measuring IOP through the eyelid enables it to provide more accurate IOP readings than those obtained by transcorneal techniques.

Circadian rhythm in melatonin release as a mechanism to reinforce the temporal organization of the circadian system in crayfish.

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Mendoza-Vargas, Leonor; Báez-Saldaña, Armida; Alvarado, Ramón; Fuentes-Pardo, Beatriz; Flores-Soto, Edgar; Solís-Chagoyán, Héctor

2017-06-01

Melatonin (MEL) is a conserved molecule with respect to its synthesis pathway and functions. In crayfish, MEL content in eyestalks (Ey) increases at night under the photoperiod, and this indoleamine synchronizes the circadian rhythm of electroretinogram amplitude, which is expressed by retinas and controlled by the cerebroid ganglion (CG). The aim of this study was to determine whether MEL content in eyestalks and CG or circulating MEL in hemolymph (He) follows a circadian rhythm under a free-running condition; in addition, it was tested whether MEL might directly influence the spontaneous electrical activity of the CG. Crayfish were maintained under constant darkness and temperature, a condition suitable for studying the intrinsic properties of circadian systems. MEL was quantified in samples obtained from He, Ey, and CG by means of an enzyme-linked immunosorbent assay, and the effect of exogenous MEL on CG spontaneous activity was evaluated by electrophysiological recording. Variation of MEL content in He, Ey, and CG followed a circadian rhythm that peaked at the same circadian time (CT). In addition, a single dose of MEL injected into the crayfish at different CTs reduced the level of spontaneous electrical activity in the CG. Results suggest that the circadian increase in MEL content directly affects the CG, reducing its spontaneous electrical activity, and that MEL might act as a periodical signal to reinforce the organization of the circadian system in crayfish.

The Molecular Circadian Clock and Alcohol-Induced Liver Injury

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Uduak S. Udoh

2015-10-01

Full Text Available Emerging evidence from both experimental animal studies and clinical human investigations demonstrates strong connections among circadian processes, alcohol use, and alcohol-induced tissue injury. Components of the circadian clock have been shown to influence the pathophysiological effects of alcohol. Conversely, alcohol may alter the expression of circadian clock genes and the rhythmic behavioral and metabolic processes they regulate. Therefore, we propose that alcohol-mediated disruption in circadian rhythms likely underpins many adverse health effects of alcohol that cut across multiple organ systems. In this review, we provide an overview of the circadian clock mechanism and showcase results from new studies in the alcohol field implicating the circadian clock as a key target of alcohol action and toxicity in the liver. We discuss various molecular events through which alcohol may work to negatively impact circadian clock-mediated processes in the liver, and contribute to tissue pathology. Illuminating the mechanistic connections between the circadian clock and alcohol will be critical to the development of new preventative and pharmacological treatments for alcohol use disorders and alcohol-mediated organ diseases.

How does healthy aging impact on the circadian clock?

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Popa-Wagner, Aurel; Buga, Ana-Maria; Dumitrascu, Dinu Iuliu; Uzoni, Adriana; Thome, Johannes; Coogan, Andrew N

2017-02-01

Circadian rhythms are recurring patterns in a host of physiological and other parameters that recur with periods of near 24 h. These rhythms reflect the temporal organization of an organism's homeostatic control systems and as such are key processes in ensuring optimal physiological performance. Dysfunction of circadian processes is linked with adverse health conditions. In this review we highlight the evidence that normal, healthy aging is associated with changes in the circadian system; we examine the molecular mechanisms through which such changes may arise, discuss whether more robust circadian function is a predictor of longevity and highlight the role of circadian rhythms in age-related diseases. Overall, the literature shows that aging is associated with marked changes in circadian processes, both at the behavioral and molecular levels, and the molecular mechanisms through which such changes arise remain to be elucidated, but may involve inflammatory process, redox homeostasis and epigenetic modifications. Understanding the nature of age-related circadian dysfunction will allow for the design of chronotherapeutic intervention strategies to attenuate circadian dysfunction and thus improve health and quality of life.

Immunity's fourth dimension: approaching the circadian-immune connection.

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Arjona, Alvaro; Silver, Adam C; Walker, Wendy E; Fikrig, Erol

2012-12-01

The circadian system ensures the generation and maintenance of self-sustained ~24-h rhythms in physiology that are linked to internal and environmental changes. In mammals, daily variations in light intensity and other cues are integrated by a hypothalamic master clock that conveys circadian information to peripheral molecular clocks that orchestrate physiology. Multiple immune parameters also vary throughout the day and disruption of circadian homeostasis is associated with immune-related disease. Here, we discuss the molecular links between the circadian and immune systems and examine their outputs and disease implications. Understanding the mechanisms that underlie circadian-immune crosstalk may prove valuable for devising novel prophylactic and therapeutic interventions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Activation of autophagy in a rat model of retinal ischemia following high intraocular pressure.

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Antonio Piras

Full Text Available Acute primary open angle glaucoma is an optic neuropathy characterized by the elevation of intraocular pressure, which causes retinal ischemia and neuronal death. Rat ischemia/reperfusion enhances endocytosis of both horseradish peroxidase (HRP or fluorescent dextran into ganglion cell layer (GCL neurons 24 h after the insult. We investigated the activation of autophagy in GCL-neurons following ischemia/reperfusion, using acid phosphatase (AP histochemistry and immunofluorescence against LC3 and LAMP1. Retinal I/R lead to the appearance of AP-positive granules and LAMP1-positive vesicles 12 and 24 h after the insult, and LC3 labelling at 24 h, and induced a consistent retinal neuron death. At 48 h the retina was negative for autophagic markers. In addition, Western Blot analysis revealed an increase of LC3 levels after damage: the increase in the conjugated, LC3-II isoform is suggestive of autophagic activity. Inhibition of autophagy by 3-methyladenine partially prevented death of neurons and reduces apoptotic markers, 24 h post-lesion. The number of neurons in the GCL decreased significantly following I/R (I/R 12.21±1.13 vs controls 19.23±1.12 cells/500 µm; this decrease was partially prevented by 3-methyladenine (17.08±1.42 cells/500 µm, which potently inhibits maturation of autophagosomes. Treatment also prevented the increase in glial fibrillary acid protein immunoreactivity elicited by I/R. Therefore, targeting autophagy could represent a novel and promising treatment for glaucoma and retinal ischemia.

Effects of submaximal exercise with water ingestion on intraocular pressure in healthy human males

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Moura M.A.

2002-01-01

Full Text Available The effects of exercise and water replacement on intraocular pressure (IOP have not been well established. Furthermore, it is not known whether the temperature of the fluid ingested influences the IOP response. In the present study we determined the effect of water ingestion at three temperatures (10, 24 and 38ºC; 600 ml 15 min before and 240 ml 15, 30 and 45 min after the beginning of each experimental session on the IOP of six healthy male volunteers (age = 24.0 ± 3.5 years, weight = 67.0 ± 4.8 kg, peak oxygen uptake (VO2peak = 47.8 ± 9.1 ml kg-1 min-1. The subjects exercised until exhaustion on a cycle ergometer at a 60% VO2peak in a thermoneutral environment. IOP was measured before and after exercise and during recovery (15, 30 and 45 min using the applanation tonometry method. Skin and rectal temperatures, heart rate and oxygen uptake were measured continuously. IOP was similar for the right eye and the left eye and increased post-water ingestion under both exercising and resting conditions (P<0.05 but did not differ between resting and exercising situations, or between the three water temperatures. Time to exhaustion was not affected by the different water temperatures. Rectal temperature, hydration status, heart rate, oxygen uptake, carbon dioxide extraction and lactate concentration were increased by exercise but were not affected by water temperature. We conclude that IOP was not affected by exercise and that water ingestion increased IOP as expected, regardless of water temperature.

Circadian Stress Regimes Affect the Circadian Clock and Cause Jasmonic Acid-Dependent Cell Death in Cytokinin-Deficient Arabidopsis Plants[OPEN

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Nitschke, Silvia; Cortleven, Anne; Iven, Tim; Havaux, Michel; Schmülling, Thomas

2016-01-01

The circadian clock helps plants measure daylength and adapt to changes in the day-night rhythm. We found that changes in the light-dark regime triggered stress responses, eventually leading to cell death, in leaves of Arabidopsis thaliana plants with reduced cytokinin levels or defective cytokinin signaling. Prolonged light treatment followed by a dark period induced stress and cell death marker genes while reducing photosynthetic efficiency. This response, called circadian stress, is also characterized by altered expression of clock and clock output genes. In particular, this treatment strongly reduced the expression of CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY). Intriguingly, similar changes in gene expression and cell death were observed in clock mutants lacking proper CCA1 and LHY function. Circadian stress caused strong changes in reactive oxygen species- and jasmonic acid (JA)-related gene expression. The activation of the JA pathway, involving the accumulation of JA metabolites, was crucial for the induction of cell death, since the cell death phenotype was strongly reduced in the jasmonate resistant1 mutant background. We propose that adaptation to circadian stress regimes requires a normal cytokinin status which, acting primarily through the AHK3 receptor, supports circadian clock function to guard against the detrimental effects of circadian stress. PMID:27354555

Black diaphragm intraocular lens implantation and penetrating keratoplasty in aphakic eyes with traumatic aniridia

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Xiao-Guang Dong

2013-04-01

Full Text Available AIM: To evaluate the long-term outcome of implantation of black diaphragm intraocular (BDI lens combined with penetrating keratoplasty (PKP for managing aphakic eyes with traumatic aniridia and corneal damage. METHODS: Six aphakic eyes of six patients with traumatic aniridia and corneal damage had BDI lens implantation at Qingdao Eye Hospital, Shandong Eye Institute from June 2008 to November 2011. Medical records of the patients were reviewed. Three patients received PKP and after 12-18months were implanted with BDI lens. The other three patients completed PKP and BDI lens implantation at the same time. The corrected visual acuity, intraocular pressure and number of corneal endothelial cells were monitored. RESULTS: The patients were followed up for an average of 24.3±12.1months (range 14-48 months. All BDI lenses were located well. The best corrected visual acuity got improved in 5 patients (0.1-1.0 and decreased in 1 patient from 0.4 to 0.2. Three patients had normal intraocular pressure (IOP after implantation. Two patients required antiglaucoma medications to control IOP within the normal range and 1 patient implanted Ahmed glaucoma valve to control IOP. The corneal grafts kept transparent in all eyes and the corneal endothelial counting >1 000/mm2, although two patients experienced acute graft rejection and loss more than 30% corneal endothelial cells. CONCLUSION: Implantation of BDI lens combined with PKP is an effective option for managing aphakic eyes with traumatic aniridia and corneal damage. Although the results in our study are encouraging, additional studies of the long-term safety and efficacy are required. A larger study population and longer follow-up may be beneficial.

Circadian Metabolomics in Time and Space

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Kenneth A. Dyar

2017-07-01

Full Text Available Circadian rhythms are widely known to govern human health and disease, but specific pathogenic mechanisms linking circadian disruption to metabolic diseases are just beginning to come to light. This is thanks in part to the development and application of various “omics”-based tools in biology and medicine. Current high-throughput technologies allow for the simultaneous monitoring of multiple dynamic cellular events over time, ranging from gene expression to metabolite abundance and sub-cellular localization. These fundamental temporal and spatial perspectives have allowed for a more comprehensive understanding of how various dynamic cellular events and biochemical processes are related in health and disease. With advances in technology, metabolomics has become a more routine “omics” approach for studying metabolism, and “circadian metabolomics” (i.e., studying the 24-h metabolome has recently been undertaken by several groups. To date, circadian metabolomes have been reported for human serum, saliva, breath, and urine, as well as tissues from several species under specific disease or mutagenesis conditions. Importantly, these studies have consistently revealed that 24-h rhythms are prevalent in almost every tissue and metabolic pathway. Furthermore, these circadian rhythms in tissue metabolism are ultimately linked to and directed by internal 24-h biological clocks. In this review, we will attempt to put these data-rich circadian metabolomics experiments into perspective to find out what they can tell us about metabolic health and disease, and what additional biomarker potential they may reveal.

Circadian Rhythms, Sleep Deprivation, and Human Performance

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Goel, Namni; Basner, Mathias; Rao, Hengyi; Dinges, David F.

2014-01-01

Much of the current science on, and mathematical modeling of, dynamic changes in human performance within and between days is dominated by the two-process model of sleep–wake regulation, which posits a neurobiological drive for sleep that varies homeostatically (increasing as a saturating exponential during wakefulness and decreasing in a like manner during sleep), and a circadian process that neurobiologically modulates both the homeostatic drive for sleep and waking alertness and performance. Endogenous circadian rhythms in neurobehavioral functions, including physiological alertness and cognitive performance, have been demonstrated using special laboratory protocols that reveal the interaction of the biological clock with the sleep homeostatic drive. Individual differences in circadian rhythms and genetic and other components underlying such differences also influence waking neurobehavioral functions. Both acute total sleep deprivation and chronic sleep restriction increase homeostatic sleep drive and degrade waking neurobehavioral functions as reflected in sleepiness, attention, cognitive speed, and memory. Recent evidence indicating a high degree of stability in neurobehavioral responses to sleep loss suggests that these trait-like individual differences are phenotypic and likely involve genetic components, including circadian genes. Recent experiments have revealed both sleep homeostatic and circadian effects on brain metabolism and neural activation. Investigation of the neural and genetic mechanisms underlying the dynamically complex interaction between sleep homeostasis and circadian systems is beginning. A key goal of this work is to identify biomarkers that accurately predict human performance in situations in which the circadian and sleep homeostatic systems are perturbed. PMID:23899598

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

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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.

Modification of hydrophobic acrylic intraocular lens with poly(ethylene glycol) by atmospheric pressure glow discharge: A facile approach

International Nuclear Information System (INIS)

Lin Lin; Wang Yao; Huang Xiaodan; Xu Zhikang; Yao Ke

2010-01-01

To improve the anterior surface biocompatibility of hydrophobic acrylic intraocular lens (IOL) in a convenient and continuous way, poly(ethylene glycol)s (PEGs) were immobilized by atmospheric pressure glow discharge (APGD) treatment using argon as the discharge gas. The hydrophilicity and chemical changes on the IOL surface were characterized by static water contact angle and X-ray photoelectron spectroscopy to confirm the covalent binding of PEG. The morphology of the IOL surface was observed under field emission scanning electron microscopy and atomic force microscopy. The surface biocompatibility was evaluated by adhesion experiments with platelets, macrophages, and lens epithelial cells (LECs) in vitro. The results revealed that the anterior surface of the PEG-grafted IOL displayed significantly and permanently improved hydrophilicity. Cell repellency was observed, especially in the PEG-modified IOL group, which resisted the attachment of platelets, macrophages and LECs. Moreover, the spread and growth of cells were suppressed, which may be attributed to the steric stabilization force and chain mobility effect of the modified PEG. All of these results indicated that hydrophobic acrylic IOLs can be hydrophilic modified by PEG through APGD treatment in a convenient and continuous manner which will provide advantages for further industrial applications.

5.2-GHz RF Power Harvester in 0.18-/spl mu/m CMOS for Implantable Intraocular Pressure Monitoring

KAUST Repository

Ouda, Mahmoud H.

2013-04-17

A first fully integrated 5.2-GHz CMOS-based RF power harvester with an on-chip antenna is presented in this paper. The design is optimized for sensors implanted inside the eye to wirelessly monitor the intraocular pressure of glaucoma patients. It includes a five-stage RF rectifier with an on-chip antenna, a dc voltage limiter, two voltage sensors, a low dropout voltage regulator, and MOSCAP based on-chip storage. The chip has been designed and fabricated in a standard 0.18-μm CMOS technology. To emulate the eye environment in measurements, a custom test setup is developed that comprises Plexiglass cavities filled with saline solution. Measurements in this setup show that the proposed chip can be charged to 1 V wirelessly from a 5-W transmitter 3 cm away from the harvester chip. The energy that is stored on the 5-nF on-chip MOSCAP when charged to 1 V is 2.5 nJ, which is sufficient to drive an arbitrary 100-μW load for 9 μs at regulated 0.8 V. Simulated efficiency of the rectifier is 42% at -7 dBm of input power.

Effects of topical hypotensive drugs on circadian IOP, blood pressure, and calculated diastolic ocular perfusion pressure in patients with glaucoma.

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Quaranta, Luciano; Gandolfo, Federico; Turano, Raffaele; Rovida, Federico; Pizzolante, Teodoro; Musig, Andrea; Gandolfo, Enrico

2006-07-01

To compare the short-term effects of timolol 0.5%, brimonidine 0.2%, dorzolamide 2%, and latanoprost 0.005% on intraocular pressure (IOP), blood pressure (BP), and diastolic ocular perfusion pressure (DOPP), calculated as the difference between the diastolic blood pressure (DBP) and IOP. According to a 4 x 4 Latin squares design for repeated measures, 27 untreated patients and patients with newly diagnosed primary open-angle glaucoma (POAG) were treated with timolol 0.5% at 8 AM and 8 PM; brimonidine 0.2% at 8 AM and 8 PM; dorzolamide 2% at 8 AM, 2 PM, and 8 PM; and latanoprost 0.005% at 8 PM. The duration of each treatment course was 6-weeks, with a 4-week washout between each treatment. IOP and BP were measured at baseline and at the end of each treatment period. IOP was measured every 2 hours throughout a 24-hour period. Sitting IOP was measured from 8 AM to 10 PM by Goldmann applanation tonometry. Supine IOP was assessed from 12 to 6 AM by means of a handheld electronic tonometer (TonoPen XL; Mentor, Norwell, MA). BP monitoring was performed by means of an automated portable device (TM-2430; A & D Co., Saitama, Japan). All the drugs tested decreased the IOP significantly at all time points in comparison with baseline pressure. The mean 24-hour IOP after latanoprost administration (16.62+/-0.98 mm Hg) was significantly lower than that after timolol, brimonidine, or dorzolamide (P=0.0001). During the 24-hour period, brimonidine induced a significant decrease in systolic BP (SBP) and DBP at all time points when compared with baseline measurements and with those after administration of the other drugs (P<0.0001). Timolol caused a significant decrease in DBP and SBP at all the 24-hour time points when compared with the baseline and with the dorzolamide- and latanoprost-induced changes (P<0.0001). The mean 24-hour DOPPs were 50.7+/-5.9 mm Hg at baseline, 53+/-5.5 mm Hg with timolol, 46.2+/-5.4 mm Hg with brimonidine, 55.9+/-4.6 mm Hg with dorzolamide, and 56

The Drosophila melanogaster circadian pacemaker circuit

Indian Academy of Sciences (India)

2016-08-26

Aug 26, 2016 ... Keywords. circadian rhythm; neuronal network; ion channel; behaviour; neurotransmitter; electrophysiology; Drosophila. Abstract. As an experimental model system, the fruit fly Drosophila melanogaster has been seminal in shaping our understanding of the circadian clockwork. The wealth of genetic tools ...

Apraclonidine versus brinzolamide-timolol combination to prevent intraocular pressure elevation after laser capsulotomy

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Erkan Çelik

2016-01-01

Full Text Available AIM: To compare the efficacy of fixed combination of brinzolamide 1% and timolol 0.5%(FCBTwith apraclonidine 0.5%(APRAin preventing intraocular pressure(IOPelevations after neodymium: yttrium-aluminum-garnet(Nd:YAGlaser posterior capsulotomy.METHODS: This prospective randomized clinical study included 90 eyes of 90 consecutive patients who had Nd:YAG laser posterior capsulotomy for posterior capsule opacification(PCO. Patients were randomized to receive APRA(n=45or FCBT(n=45at 1h before laser surgery. A masked observer measured IOP by Goldmann applanation tonometry before the procedure and at 1, 2, 3, 24h and 7d after laser treatment. IOP outcome measures were grouped into the following categories: post laser IOP elevation of 5 to RESULTS:The mean IOP before surgery on the day of the procedure was 14.1±2.1 mm Hg in the APRA group and 13.2±2.1 mm Hg in the FCBT group. There was no statistically significant difference between the APRA and the FCBT groups of baseline IOPs measured(P=0.066. During the follow-up time, the mean IOP was lower in FCBT group, but this was not statistically significant. Six patients(13.3%in APRA group and 4(8.9%in FCBT group had IOP elevations of 5 to P=0.243. IOP elevations of 10 mm Hg or more occurred in 3 eyes(6.7%in the APRA group and 1 eyes(2.2%in the FCBT group; this was not statistically significant(P=0.542. CONCLUSION:Both of APRA and FCBT are effective for prevention and APRA is enough for most of routine cases. FCBT may be an option for the eyes those need more IOP reduction such as pre-existing glaucoma patients who are at higher risk for postoperative IOP elevations.

Autotaxin-lysophosphatidic acid axis is a novel molecular target for lowering intraocular pressure.

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Padma Iyer

Full Text Available Primary open-angle glaucoma is the second leading cause of blindness in the United States and is commonly associated with elevated intraocular pressure (IOP resulting from diminished aqueous humor (AH drainage through the trabecular pathway. Developing effective therapies for increased IOP in glaucoma patients requires identification and characterization of molecular mechanisms that regulate IOP and AH outflow. This study describes the identification and role of autotaxin (ATX, a secretory protein and a major source for extracellular lysophosphatidic acid (LPA, in regulation of IOP in a rabbit model. Quantitative proteomics analysis identified ATX as an abundant protein in both human AH derived from non-glaucoma subjects and in AH from different animal species. The lysophospholipase D (LysoPLD activity of ATX was found to be significantly elevated (by ∼1.8 fold; n=20 in AH derived from human primary open angle glaucoma patients as compared to AH derived from age-matched cataract control patients. Immunoblotting analysis of conditioned media derived from primary cultures of human trabecular meshwork (HTM cells has confirmed secretion of ATX and the ability of cyclic mechanical stretch of TM cells to increase the levels of secreted ATX. Topical application of a small molecular chemical inhibitor of ATX (S32826, which inhibited AH LysoPLD activity in vitro (by >90%, led to a dose-dependent and significant decrease of IOP in Dutch-Belted rabbits. Single intracameral injection of S32826 (∼2 µM led to significant reduction of IOP in rabbits, with the ocular hypotensive response lasting for more than 48 hrs. Suppression of ATX expression in HTM cells using small-interfering RNA (siRNA caused a decrease in actin stress fibers and myosin light chain phosphorylation. Collectively, these observations indicate that the ATX-LPA axis represents a potential therapeutic target for lowering IOP in glaucoma patients.

Simultaneous Implantation of an Ahmed and Baerveldt Glaucoma Drainage Device for Uncontrolled Intraocular Pressure in Advanced Glaucoma.

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Rao, Veena S; Christenbury, Joseph; Lee, Paul; Allingham, Rand; Herndon, Leon; Challa, Pratap

2017-02-01

To evaluate efficacy and safety of a novel technique, simultaneous implantation of Ahmed and Baerveldt shunts, for improved control of intraocular pressure (IOP) in advanced glaucoma with visual field defects threatening central fixation. Retrospective case series; all patients receiving simultaneous Ahmed and Baerveldt implantation at a single institution between October 2004 and October 2009 were included. Records were reviewed preoperatively and at postoperative day 1, week 1, month 1, month 3, month 6, year 1, and yearly until year 5. Outcome measures included IOP, best-corrected visual acuity, visual field mean deviation, cup to disc ratio, number of glaucoma medications, and complications. Fifty-nine eyes were identified; mean (±SD) follow-up was 26±23 months. Primary open-angle glaucoma was most common (n=37, 63%). Forty-six eyes (78%) had prior incisional surgery. Mean preoperative IOP was 25.5±9.8 mm Hg. IOP was reduced 50% day 1 (Pglaucoma tube implantation with effects persisting over postoperative year 1 and up to year 5. Complications were higher than that seen in reports of single shunt implantation, which may be explained by patient complexity in this cohort. This technique may prove a promising novel approach for management of uncontrolled IOP in advanced glaucoma.

Circadian modulation of short-term memory in Drosophila.

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Lyons, Lisa C; Roman, Gregg

2009-01-01

Endogenous biological clocks are widespread regulators of behavior and physiology, allowing for a more efficient allocation of efforts and resources over the course of a day. The extent that different processes are regulated by circadian oscillators, however, is not fully understood. We investigated the role of the circadian clock on short-term associative memory formation using a negatively reinforced olfactory-learning paradigm in Drosophila melanogaster. We found that memory formation was regulated in a circadian manner. The peak performance in short-term memory (STM) occurred during the early subjective night with a twofold performance amplitude after a single pairing of conditioned and unconditioned stimuli. This rhythm in memory is eliminated in both timeless and period mutants and is absent during constant light conditions. Circadian gating of sensory perception does not appear to underlie the rhythm in short-term memory as evidenced by the nonrhythmic shock avoidance and olfactory avoidance behaviors. Moreover, central brain oscillators appear to be responsible for the modulation as cryptochrome mutants, in which the antennal circadian oscillators are nonfunctional, demonstrate robust circadian rhythms in short-term memory. Together these data suggest that central, rather than peripheral, circadian oscillators modulate the formation of short-term associative memory and not the perception of the stimuli.

Photoperiodic plasticity in circadian clock neurons in insects

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Sakiko eShiga

2013-08-01

Full Text Available Since Bünning’s observation of circadian rhythms and photoperiodism in the runner bean Phaseolus multiflorus in 1936, many studies have shown that photoperiodism is based on the circadian clock system. In insects, involvement of circadian clock genes or neurons has been recently shown in the photoperiodic control of developmental arrests, diapause. Based on molecular and neuronal studies in Drosophila melanogaster, photoperiodic changes have been reported for expression patterns of the circadian clock genes, subcellular distribution of clock proteins, fiber distribution, or the number of plausible clock neurons in different species. Photoperiod sets peaks of per or tim mRNA abundance at lights-off in Sarcophaga crassipalpis, Chymomyza costata and Protophormia terraenovae. Abundance of per and Clock mRNA changes by photoperiod in Pyrrhocoris apterus. Subcellular Per distribution in circadian clock neurons changes with photoperiod in P. terraenovae. Although photoperiodism is not known in Leucophaea maderae, under longer day length, more stomata and longer commissural fibers of circadian clock neurons have been found. These plastic changes in the circadian clock neurons could be an important constituent for photoperiodic clock mechanisms to integrate repetitive photoperiodic information and produce different outputs based on day length.

Sleep, circadian rhythm and body weight: parallel developments.

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Westerterp-Plantenga, Margriet S

2016-11-01

Circadian alignment is crucial for body-weight management, and for metabolic health. In this context, circadian alignment consists of alignment of sleep, meal patterns and physical activity. During puberty a significant reduction in sleep duration occurs, and pubertal status is inversely associated with sleep duration. A consistent inverse association between habitual sleep duration and body-weight development occurs, independent of possible confounders. Research on misalignment reveals that circadian misalignment affects sleep-architecture and subsequently disturbs glucose-insulin metabolism, substrate oxidation, leptin- and ghrelin concentrations, appetite, food reward, hypothalamic-pituitary-adrenal-axis activity and gut-peptide concentrations enhancing positive energy balance and metabolic disturbance. Not only aligning meals and sleep in a circadian way is crucial, also regular physical activity during the day strongly promotes the stability and amplitude of circadian rhythm, and thus may serve as an instrument to restore poor circadian rhythms. Endogenicity may play a role in interaction of these environmental variables with a genetic predisposition. In conclusion, notwithstanding the separate favourable effects of sufficient daily physical activity, regular meal patterns, sufficient sleep duration and quality sleep on energy balance, the overall effect of the amplitude and stability of the circadian rhythm, perhaps including genetic predisposition, may integrate the separate effects in an additive way.

Intraocular osseous metaplasia. A clinico-pathological study

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Vemuganti Geeta; Honavar Santosh; Jalali Subhadra

2002-01-01

Purpose: To evaluate the clinico-pathologic features of intraocular osseous metaplasia. Methods: Pathology specimens of enucleated eyes submitted to the ophthalmic pathology service at a tertiary eye-care referral center between January 1995 and June 1999 were studied for intraocular osseous metaplasia. Specific histopathologic features noted in specimens with osseous metaplasia were the presence of retinal detachment, gliosis, retinal pigment epithelial hyperplasia, drusen, epiretinal membra...

Phacoemulsification with intraocular lens implantation in primary angle-closure suspect, primary angle-closure and primary angle-closure glaucoma with cataract

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Kun Zeng

2013-08-01

Full Text Available AIM: To evaluate the features and clinical outcomes of cataract extraction by phacoemulsification with intraocular lens implantation in primary angle-closure suspect(PACS, primary angle-closure(PACand primary angle-closure glaucoma(PACGwith cataract.METHODS:Phacoemulsification with intraocular lens implantation was performed on 86 cases(86 eyesdiagnosed as PACS, PAC and PACG co-existing cataract from January to December 2012. All cases were followed up for 3 months to 1 year. Pre-operative and post-operative visual acuity, intraocular pressure(IOP, gonioscopy, ultrasound biomicroscopy(UBM, visual field and usage of anti-glaucomaous eye drops were recorded.RESULTS:Zonular dialysis existed in 19 eyes(22%. The post-operative visual acuity improved in 84 eyes(98%. The post-operative visual acuity was CONCLUSION: PACS, PAC and PACG co-existing zonular dialysis is common. Phacoemulsification with IOL implantation can reduce IOP, deepen anterior chamber and open angle.

Pattern of intraocular pressure reduction following laser trabeculoplasty in open-angle glaucoma patients: comparison between selective and nonselective treatment

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Almeida Jr ED

2011-07-01

Full Text Available Eglailson Dantas Almeida Júnior1, Luciano Moreira Pinto1,2, Rodrigo Antonio Brant Fernandes1,2, Tiago Santos Prata1,31Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil; 2Cerpo Oftalmologia, São Paulo, Brazil; 3Hospital Medicina dos Olhos, São Paulo, BrazilObjective: To compare the pattern of intraocular pressure (IOP reduction following selective laser trabeculoplasty (SLT versus argon laser trabeculoplasty (ALT in open-angle glaucoma (OAG patients, and to investigate the ability of initial IOP reduction to predict mid-term success.Methods: A prospective, nonrandomized, interventional case series was carried out. Consecutive uncontrolled OAG glaucoma patients underwent SLT or ALT; the same preoperative medical regimen was maintained during follow-up. Data collected included age, type of OAG, pre- and postoperative IOP, number of glaucoma medications, and surgical complications. Post-treatment assessments were scheduled at day 1 and 7 and months 1, 3, and 6.Results: A total of 45 patients (45 eyes were enrolled [SLT group (n = 25; ALT group (n = 20]. Groups were similar for age, baseline IOP, and number of glaucoma medications (P ≥ 0.12. We found no significant differences in mean IOP reduction between SLT (5.1 ± 2.5 mmHg; 26.6% and ALT (4.4 ± 2.8 mmHg; 22.8% groups at month 6 (P = 0.38. Success rates (IOP ≤ 16 mmHg and IOP reduction ≥25% at last follow-up visit were similar for SLT (72% and ALT (65% groups (P = 0.36. Comparing the pattern of IOP reduction (% of IOP reduction at each visit between groups, we found a greater effect following SLT compared with ALT at day 7 (23.7% ± 13.7% vs 8.1% ± 9.5%; P < 0.001. No significant differences were observed at other time points (P ≥ 0.32. Additionally, the percentage of IOP reduction at day 7 and at month 6 were significantly correlated in the SLT group (R2 = 0.36; P < 0.01, but not in the ALT group (P = 0.89. Early postoperative success predicted late

Resultados da troca de lente intra-ocular de hidrogel opacificada

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Salera Cristina Moreira

2004-01-01

Full Text Available OBJETIVO: Avaliar os resultados da explantação e substituição das lentes intra-oculares (LIO de hidrogel opacificadas. MÉTODOS: Foram analisados retrospectivamente os prontuários de 12 pacientes (15 olhos submetidos à explantação e substituição das lentes intra-oculares de hidrogel opacificadas. RESULTADOS: A opacificação das lentes intra-oculares de hidrogel causou perdas de linhas de visão em 13 olhos (86,7%. A troca das lentes intra-oculares opacificadas promoveu o ganho de linhas de visão em 11 olhos (73,3%. As complicações peroperatórias ocorreram em três olhos (20% e foram as seguintes: perda de óleo de silicone, ruptura total de zônula com perda do saco capsular e ruptura parcial de zônula. Durante a explantação das lentes intra-oculares foi necessária a realização de incisões relaxantes na borda da capsulorrexe anterior em três olhos (20% e em dois olhos (13,3% os hápticos foram cortados sendo retirada somente a zona óptica das lentes intra-oculares. CONCLUSÃO: A cirurgia para explantação e substituição das lentes intra-oculares opacificadas mostrou-se eficaz naqueles pacientes com perdas de linhas de visão (p > 0,05.

Circadian Rhythms, Sleep, and Disorders of Aging.

Science.gov (United States)

Mattis, Joanna; Sehgal, Amita

2016-04-01

Sleep-wake cycles are known to be disrupted in people with neurodegenerative disorders. These findings are now supported by data from animal models for some of these disorders, raising the question of whether the disrupted sleep/circadian regulation contributes to the loss of neural function. As circadian rhythms and sleep consolidation also break down with normal aging, changes in these may be part of what makes aging a risk factor for disorders like Alzheimer's disease (AD). Mechanisms underlying the connection between circadian/sleep dysregulation and neurodegeneration remain unclear, but several recent studies provide interesting possibilities. While mechanistic analysis is under way, it is worth considering treatment of circadian/sleep disruption as a means to alleviate symptoms of neurodegenerative disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

Solid intraocular xanthogranuloma in three Miniature Schnauzer dogs.

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Zarfoss, Mitzi K; Dubielzig, Richard R

2007-01-01

Macrophages that contain abundant intracytoplasmic lipid are called 'foam cells'. In four canine globes submitted to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW), foam cells formed a solid intraocular mass. The purpose of this study was to describe the histopathologic findings in these cases. The electronic COPLOW database (1993-2006) was searched for the diagnosis of 'foam cell tumor'. Clinical history, gross pathology and histopathology (5-micron sections, hematoxylin and eosin and Alcian blue periodic acid Schiff) were reviewed in all cases. Cases were included if the globe was grossly filled by a solid mass and if all intraocular structures were effaced by lipid-laden foam cell macrophages admixed with birefringent, Alcian blue-positive crystals oriented in stellate patterns. All three patients (four globes) satisfying the selection criteria were Miniature Schnauzers. In all cases the clinical history included diabetes mellitus, hyperlipidemia and chronic bilateral uveitis that was interpreted to be lens-induced. All globes were enucleated because of glaucoma. The term solid intraocular xanthogranuloma was used to describe these cases because the intraocular contents were effaced by a solid mass of foam cells and birefringent crystals. The cases in this report suggest that diabetic Miniature Schnauzers with hyperlipidemia are at risk for lipid and macrophage-rich uveitis, which may in some cases form a solid inflammatory intraocular mass, precipitate glaucoma, and lead to enucleation.

The Circadian Clock-controlled Transcriptome of Developing Soybean Seeds

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Karen A. Hudson

2010-07-01

Full Text Available A number of metabolic and physiological processes in plants are controlled by the circadian clock, which enables a plant to anticipate daily changes in the environment. Relatively little is known about circadian rhythms in developing seeds, which may be important for determining the extent and timing of nutrient storage in grain. Microarray expression profiling was used to identify genes expressed in developing soybean ( seeds that are controlled by the circadian clock. Genes with predicted functions in protein synthesis, fatty acid metabolism, and photosynthesis totaling 1.8% of the mRNAs detected in seed were found to be expressed in a circadian rhythm. Known circadian and light-controlled promoter elements were identified as over-represented in the promoters of clock-controlled seed genes, with the over-represented elements varying according to the phase of circadian expression. A subset of circadian-regulated genes were found to be expressed in different phases in developing seeds with respect to leaves from the same plants, many of which have roles in photosynthesis and carbon metabolism. These results help to characterize the genes and processes in seeds that may be regulated by the circadian clock, and provide some insight into organ-specific phasing of clock controlled gene expression.

Absence of nocturnal fall in blood pressure in elderly persons with Alzheimer-type dementia.

Science.gov (United States)

Otsuka, A; Mikami, H; Katahira, K; Nakamoto, Y; Minamitani, K; Imaoka, M; Nishide, M; Ogihara, T

1990-09-01

Circadian changes of the blood pressure and heart rate in elderly normotensive bedridden patients with severe dementia of the Alzheimer type (group D) were compared with those in elderly normotensive bedridden patients without dementia (group R), normotensive subjects with normal daily activity (group N), and hypertensive patients with normal daily activity (group H). In groups R, N, and H, the blood pressure increased in the afternoon and decreased at midnight; in group D, however, although it increased in the afternoon, it did not decrease at night. The circadian changes of the heart rate were similar in all four groups, showing maxima in the afternoon and minima at midnight. Thus, a specific alteration was found in the circadian rhythm of the blood pressure in patients with Alzheimer-type dementia.

Sleep Apnea and Circadian Extracellular Fluid Change as Independent Factors for Nocturnal Polyuria.

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Niimi, Aya; Suzuki, Motofumi; Yamaguchi, Yasuhiro; Ishii, Masaki; Fujimura, Tetsuya; Nakagawa, Tohru; Fukuhara, Hiroshi; Kume, Haruki; Igawa, Yasuhiko; Akishita, Masahiro; Homma, Yukio

2016-10-01

We investigated the relationships among nocturnal polyuria, sleep apnea and body fluid volume to elucidate the pathophysiology of nocturia in sleep apnea syndrome. We enrolled 104 consecutive patients who underwent polysomnography for suspected sleep apnea syndrome. Self-assessed symptom questionnaires were administered to evaluate sleep disorder and lower urinary tract symptoms, including nocturia. Voiding frequency and voided volume were recorded using a 24-hour frequency-volume chart. Body fluid composition was estimated in the morning and at night using bioelectric impedance analysis. Frequency-volume chart data were analyzed in 22 patients after continuous positive airway pressure therapy. Patients with nocturnal polyuria showed a higher apnea-hypopnea index (33.9 vs 24.2, p = 0.03) and a larger circadian change in extracellular fluid adjusted to lean body mass (0.22 vs -0.19, p = 0.019) than those without nocturnal polyuria. These relations were more evident in patients 65 years old or older than in those 64 years or younger. A multivariate linear regression model showed an independent relationship of nocturnal polyuria with the apnea-hypopnea index and the circadian change in extracellular fluid adjusted to lean body mass (p = 0.0012 and 0.022, respectively). Continuous positive airway pressure therapy significantly improved nocturnal polyuria and nocturia only in patients with nocturnal polyuria. This study identified sleep apnea and the circadian change in extracellular fluid as independent factors for nocturnal polyuria. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

System identification of the Arabidopsis plant circadian system

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Foo, Mathias; Somers, David E.; Kim, Pan-Jun

2015-02-01

The circadian system generates an endogenous oscillatory rhythm that governs the daily activities of organisms in nature. It offers adaptive advantages to organisms through a coordination of their biological functions with the optimal time of day. In this paper, a model of the circadian system in the plant Arabidopsis (species thaliana) is built by using system identification techniques. Prior knowledge about the physical interactions of the genes and the proteins in the plant circadian system is incorporated in the model building exercise. The model is built by using primarily experimentally-verified direct interactions between the genes and the proteins with the available data on mRNA and protein abundances from the circadian system. Our analysis reveals a great performance of the model in predicting the dynamics of the plant circadian system through the effect of diverse internal and external perturbations (gene knockouts and day-length changes). Furthermore, we found that the circadian oscillatory rhythm is robust and does not vary much with the biochemical parameters except those of a light-sensitive protein P and a transcription factor TOC1. In other words, the circadian rhythmic profile is largely a consequence of the network's architecture rather than its particular parameters. Our work suggests that the current experimental knowledge of the gene-to-protein interactions in the plant Arabidopsis, without considering any additional hypothetical interactions, seems to suffice for system-level modeling of the circadian system of this plant and to present an exemplary platform for the control of network dynamics in complex living organisms.

ASSESSMENT OF THE CHANGES IN BLOOD PRESSURE CIRCADIAN PROFILE AND VARIABILITY IN PATIENTS WITH CHRONIC HEART FAILURE AND ARTERIAL HYPERTENSION DURING COMBINED THERAPY INCLUDING IVABRADINE

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M. V. Surovtseva

2012-01-01

Full Text Available Aim. To assess the changes in blood pressure (BP circadian profile and variability in patients with chronic heart failure (CHF of ischemic etiology and arterial hypertension (HT due to the complex therapy including ivabradine. Material and methods. Patients (n=90 with CHF class II–III NYHA associated with stable angina II-III class and HT were examined. The patients were randomized into 3 groups depending on received drugs: perindopril and ivabradine - group 1; perindopril, bisoprolol and ivabradine - group 2; perindopril and bisoprolol - group 3. The duration of therapy was 6 months. Ambulatory BP monitoring (ABPM was assessed at baseline and after treatment. Results. More significant reduction in average 24-hours systolic BP was found in groups 1 and 2 compared to group 3 (Δ%: -19.4±0,4; -21.1±0.4 and -11.8±0.6, respectively as well as diastolic BP (Δ%: -10.6±0.6; -12.9±0.4 and -4,3±0.3, respectively and other ABPM indicators. Improvement of BP circadian rhythm was found due to increase in the number of «Dipper» patients (p=0.016. More significant reduction in average daily and night systolic and diastolic BP (p=0.001, as well as daily and night BP variability (p=0.001 was also found in patients of group 2 compared to these of group 1. Conclusion. Moderate antihypertensive effect (in respect of both diastolic and systolic BP was shown when ivabradine was included into the complex therapy of patients with ischemic CHF and HT. The effect was more pronounced when ivabradine was combined with perindopril and bisoprolol. This was accompanied by reduction in high BP daily variability and improvement of the BP circadian rhythm. 

ASSESSMENT OF THE CHANGES IN BLOOD PRESSURE CIRCADIAN PROFILE AND VARIABILITY IN PATIENTS WITH CHRONIC HEART FAILURE AND ARTERIAL HYPERTENSION DURING COMBINED THERAPY INCLUDING IVABRADINE

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M. V. Surovtseva

2015-12-01

Full Text Available Aim. To assess the changes in blood pressure (BP circadian profile and variability in patients with chronic heart failure (CHF of ischemic etiology and arterial hypertension (HT due to the complex therapy including ivabradine. Material and methods. Patients (n=90 with CHF class II–III NYHA associated with stable angina II-III class and HT were examined. The patients were randomized into 3 groups depending on received drugs: perindopril and ivabradine - group 1; perindopril, bisoprolol and ivabradine - group 2; perindopril and bisoprolol - group 3. The duration of therapy was 6 months. Ambulatory BP monitoring (ABPM was assessed at baseline and after treatment. Results. More significant reduction in average 24-hours systolic BP was found in groups 1 and 2 compared to group 3 (Δ%: -19.4±0,4; -21.1±0.4 and -11.8±0.6, respectively as well as diastolic BP (Δ%: -10.6±0.6; -12.9±0.4 and -4,3±0.3, respectively and other ABPM indicators. Improvement of BP circadian rhythm was found due to increase in the number of «Dipper» patients (p=0.016. More significant reduction in average daily and night systolic and diastolic BP (p=0.001, as well as daily and night BP variability (p=0.001 was also found in patients of group 2 compared to these of group 1. Conclusion. Moderate antihypertensive effect (in respect of both diastolic and systolic BP was shown when ivabradine was included into the complex therapy of patients with ischemic CHF and HT. The effect was more pronounced when ivabradine was combined with perindopril and bisoprolol. This was accompanied by reduction in high BP daily variability and improvement of the BP circadian rhythm. 

Circadian Rhythms

Indian Academy of Sciences (India)

IAS Admin

Early studies on circadian rhythms focussed on unravelling the fundamental .... careful analysis revealed that deaths of most arrhythmic indi- viduals were due to .... is no more a sci-fi movie script and is achievable through a technique called ...

Circadian polymorphisms associated with affective disorders

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Shekhtman Tatyana

2009-01-01

Full Text Available Abstract Background Clinical symptoms of affective disorders, their response to light treatment, and sensitivity to other circadian interventions indicate that the circadian system has a role in mood disorders. Possibly the mechanisms involve circadian seasonal and photoperiodic mechanisms. Since genetic susceptibilities contribute a strong component to affective disorders, we explored whether circadian gene polymorphisms were associated with affective disorders in four complementary studies. Methods Four groups of subjects were recruited from several sources: 1 bipolar proband-parent trios or sib-pair-parent nuclear families, 2 unrelated bipolar participants who had completed the BALM morningness-eveningness questionnaire, 3 sib pairs from the GenRed Project having at least one sib with early-onset recurrent unipolar depression, and 4 a sleep clinic patient group who frequently suffered from depression. Working mainly with the SNPlex assay system, from 2 to 198 polymorphisms in genes related to circadian function were genotyped in the participant groups. Associations with affective disorders were examined with TDT statistics for within-family comparisons. Quantitative trait associations were examined within the unrelated samples. Results In NR1D1, rs2314339 was associated with bipolar disorder (P = 0.0005. Among the unrelated bipolar participants, 3 SNPs in PER3 and CSNK1E were associated with the BALM score. A PPARGC1B coding SNP, rs7732671, was associated with affective disorder with nominal significance in bipolar family groups and independently in unipolar sib pairs. In TEF, rs738499 was associated with unipolar depression; in a replication study, rs738499 was also associated with the QIDS-SR depression scale in the sleep clinic patient sample. Conclusion Along with anti-manic effects of lithium and the antidepressant effects of bright light, these findings suggest that perturbations of the circadian gene network at several levels may

Reverse pupillary block associated with pigment dispersion syndrome after in-the-bag intraocular lens implantation.

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Itagaki, Hideo; Kunikata, Toshio; Hiratsuka, Kentaro; Saito, Junichiro; Oshika, Tetsuro

2013-12-01

A 61-year-old man with high myopia who had received a systemic α1A-adrenoceptor antagonist had phacoemulsification and in-the-bag intraocular lens implantation in the right eye. One day postoperatively, marked pigment dispersion in the anterior chamber, posterior bowing of the iris, and iridodonesis were noted associated with a subsequent elevation in intraocular pressure (IOP). Pharmacological pupil dilation was effective in reducing pigment dispersion and IOP, and laser peripheral iridotomy was performed to alleviate posterior bowing of the iris. We hypothesize that dynamic changes in the aqueous humor flow by cataract surgery and latent flaccidity of the iris due to the systemic α1A-adrenoceptor antagonist caused reverse pupillary block. High myopia may be another risk factor for this complication. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Circadian rhythms regulate amelogenesis.

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Zheng, Li; Seon, Yoon Ji; Mourão, Marcio A; Schnell, Santiago; Kim, Doohak; Harada, Hidemitsu; Papagerakis, Silvana; Papagerakis, Petros

2013-07-01

Ameloblasts, the cells responsible for making enamel, modify their morphological features in response to specialized functions necessary for synchronized ameloblast differentiation and enamel formation. Secretory and maturation ameloblasts are characterized by the expression of stage-specific genes which follows strictly controlled repetitive patterns. Circadian rhythms are recognized as key regulators of the development and diseases of many tissues including bone. Our aim was to gain novel insights on the role of clock genes in enamel formation and to explore the potential links between circadian rhythms and amelogenesis. Our data shows definitive evidence that the main clock genes (Bmal1, Clock, Per1 and Per2) oscillate in ameloblasts at regular circadian (24 h) intervals both at RNA and protein levels. This study also reveals that the two markers of ameloblast differentiation i.e. amelogenin (Amelx; a marker of secretory stage ameloblasts) and kallikrein-related peptidase 4 (Klk4, a marker of maturation stage ameloblasts) are downstream targets of clock genes. Both, Amelx and Klk4 show 24h oscillatory expression patterns and their expression levels are up-regulated after Bmal1 over-expression in HAT-7 ameloblast cells. Taken together, these data suggest that both the secretory and the maturation stages of amelogenesis might be under circadian control. Changes in clock gene expression patterns might result in significant alterations of enamel apposition and mineralization. Copyright © 2013 Elsevier Inc. All rights reserved.

Recurrent symptomatic intraocular pressure spikes during hemodialysis in a patient with unilateral anterior uveitis

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Lim Su-Ho

2013-02-01

Full Text Available Abstract Background The relationship between intraocular pressure (IOP changes and hemodialysis has been evaluated for several decades. However, no report on an IOP rise in uveitis patients during hemodialysis has been previously documented. This report describes the case of an uveitis patient with repetitive IOP spikes associated with severe ocular pain during hemodialysis sessions, which resolved after glaucoma filtering surgery. Case presentation A 47-year-old male with diabetes and hypertension had complained of recurrent ocular pain in the left eye during hemodialysis sessions. A slit-lamp examination showed diffuse corneal epithelial edema with several white keratic precipitates and inflammatory cells (Grade 3+ in the anterior chamber of the left eye. No visible neovascularization or synechiae were visible on the iris or angle. Topical glaucoma eye-drops and intravenous mannitol before hemodialysis did not prevent subsequent painful IOP spikes in the left eye. At the end of hemodialysis, IOP averaged ~40 mmHg. After trabeculectomy with mitomycin C in the left eye, his IOP stabilized in the low-teens (range, 10–14 mmHg and no painful IOP spikes occurred during hemodialysis over the first postoperative year. Conclusion We present a case of recurrent painful IOP spikes during hemodialysis in a patient with unilateral anterior uveitis unresponsive to conventional medical treatment prior to hemodialysis. To our knowledge, this is the first case report of repetitive symptomatic IOP rise during hemodialysis in an uveitic glaucoma patient. This case highlights the importance of the awareness of the possibility that IOP may rise intolerably during hemodialysis in uveitis patients with a compromised outflow facility.

Resultados de implante de lente intraocular en niños Results of intraocular lens implantation in children

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Nashelly I. Mejía Cruz

2007-12-01

Full Text Available En este estudio se describen los resultados obtenidos del implante de lente intraocular en niños, quienes acudieron al servicio de Oftalmología Pediátrica de Instituto Cubano de oftalmología “Ramón Pando Ferrer” con el diagnóstico de catarata de diversas etiologías, en período comprendido entre abril del 2002 al 2005 cuyo seguimiento fue durante un año. En nuestro universo de estudio se determinan algunos parámetros como la edad del paciente, etiología de las cataratas, agudeza visual, defecto refractivo preoperatorio y posoperatorio. Se identificó el poder dióptrico del lente intraocular más frecuente, la presencia de complicaciones durante la cirugía y después de esta. Se evaluaron finalmente, los pacientes que requerían de tratamiento adicional como la capsulotomía con láser o membranectomía quirúrgica. El implante del lente intraocular a temprana edad se relacionó con buenos resultados quirúrgicos: mejoría de la agudeza visual corregida, presentándose el astigmatismo como el error refractivo más frecuente. La complicación transoperatorio y postoperatoria más frecuente fue la membrana inflamatoria, mientras que la complicación posoperatoria más frecuente fue la opacidad de la cápsula posterior.This paper described the results of the intraocular lens implantation performed in children, who had been seen at the Pediatric Ophthalmologic Service of " Ramon Pando Ferrer " Cuban Institute of Ophthalmology and had been diagnosed as having cataract of various etiologies, from April 2002 to April 2005. They were all followed-up for a year. Some parameters like the patient’s age, the etiology of cataract, visual acuity, pre-operative and post-operative refractive defect were considered in our study. The dioptric power of the most common intraocular lens and the most frequent complications during and after surgery were identified. The patients requiring additional treatment such as laser capsulotomy and surgical

Modelling of intercellular synchronization in the Drosophila circadian clock

International Nuclear Information System (INIS)

Jun-Wei, Wang; Ai-Min, Chen; Jia-Jun, Zhang; Zhan-Jiang, Yuan; Tian-Shou, Zhou

2009-01-01

In circadian rhythm generation, intercellular signaling factors are shown to play a crucial role in both sustaining intrinsic cellular rhythmicity and acquiring collective behaviours across a population of circadian neurons. However, the physical mechanism behind their role remains to be fully understood. In this paper, we propose an indirectly coupled multicellular model for the synchronization of Drosophila circadian oscillators combining both intracellular and intercellular dynamics. By simulating different experimental conditions, we find that such an indirect coupling way can synchronize both heterogeneous self-sustained circadian neurons and heterogeneous mutational damped circadian neurons. Moreover, they can also be entrained to ambient light-dark (LD) cycles depending on intercellular signaling. (cross-disciplinary physics and related areas of science and technology)

Analysis of a Gene Regulatory Cascade Mediating Circadian Rhythm in Zebrafish

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Wang, Haifang; Du, Jiulin; Yan, Jun

2013-01-01

In the study of circadian rhythms, it has been a puzzle how a limited number of circadian clock genes can control diverse aspects of physiology. Here we investigate circadian gene expression genome-wide using larval zebrafish as a model system. We made use of a spatial gene expression atlas to investigate the expression of circadian genes in various tissues and cell types. Comparison of genome-wide circadian gene expression data between zebrafish and mouse revealed a nearly anti-phase relationship and allowed us to detect novel evolutionarily conserved circadian genes in vertebrates. We identified three groups of zebrafish genes with distinct responses to light entrainment: fast light-induced genes, slow light-induced genes, and dark-induced genes. Our computational analysis of the circadian gene regulatory network revealed several transcription factors (TFs) involved in diverse aspects of circadian physiology through transcriptional cascade. Of these, microphthalmia-associated transcription factor a (mitfa), a dark-induced TF, mediates a circadian rhythm of melanin synthesis, which may be involved in zebrafish's adaptation to daily light cycling. Our study describes a systematic method to discover previously unidentified TFs involved in circadian physiology in complex organisms. PMID:23468616

Physiological effects of light on the human circadian pacemaker

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Shanahan, T. L.; Czeisler, C. A.

2000-01-01

The physiology of the human circadian pacemaker and its influence and on the daily organization of sleep, endocrine and behavioral processes is an emerging interest in science and medicine. Understanding the development, organization and fundamental properties underlying the circadian timing system may provide insight for the application of circadian principles to the practice of clinical medicine, both diagnostically (interpretation of certain clinical tests are dependent on time of day) and therapeutically (certain pharmacological responses vary with the time of day). The light-dark cycle is the most powerful external influence acting upon the human circadian pacemaker. It has been shown that timed exposure to light can both synchronize and reset the phase of the circadian pacemaker in a predictable manner. The emergence of detectable circadian rhythmicity in the neonatal period is under investigation (as described elsewhere in this issue). Therefore, the pattern of light exposure provided in the neonatal intensive care setting has implications. One recent study identified differences in both amount of sleep time and weight gain in infants maintained in a neonatal intensive care environment that controlled the light-dark cycle. Unfortunately, neither circadian phase nor the time of day has been considered in most clinical investigations. Further studies with knowledge of principles characterizing the human circadian timing system, which governs a wide array of physiological processes, are required to integrate these findings with the practice of clinical medicine.

The circadian response of intrinsically photosensitive retinal ganglion cells.

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Andrew J Zele

Full Text Available Intrinsically photosensitive retinal ganglion cells (ipRGC signal environmental light level to the central circadian clock and contribute to the pupil light reflex. It is unknown if ipRGC activity is subject to extrinsic (central or intrinsic (retinal network-mediated circadian modulation during light entrainment and phase shifting. Eleven younger persons (18-30 years with no ophthalmological, medical or sleep disorders participated. The activity of the inner (ipRGC and outer retina (cone photoreceptors was assessed hourly using the pupil light reflex during a 24 h period of constant environmental illumination (10 lux. Exogenous circadian cues of activity, sleep, posture, caffeine, ambient temperature, caloric intake and ambient illumination were controlled. Dim-light melatonin onset (DLMO was determined from salivary melatonin assay at hourly intervals, and participant melatonin onset values were set to 14 h to adjust clock time to circadian time. Here we demonstrate in humans that the ipRGC controlled post-illumination pupil response has a circadian rhythm independent of external light cues. This circadian variation precedes melatonin onset and the minimum ipRGC driven pupil response occurs post melatonin onset. Outer retinal photoreceptor contributions to the inner retinal ipRGC driven post-illumination pupil response also show circadian variation whereas direct outer retinal cone inputs to the pupil light reflex do not, indicating that intrinsically photosensitive (melanopsin retinal ganglion cells mediate this circadian variation.

Circadian Rhythms

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 11. Circadian Rhythms ... M Vaze1 Vijay Kumar Sharma1. Chronobiology Laboratory Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, PO Box 6436, Bangalore 560 064, India.

Circadian Rhythms

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 2. Circadian Rhythms: Why do ... Nikhil Vijay Kumar Sharma1. Chronobiology Laboratory Evolutionary and Organismal Biology Unit Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur, PO Box 6436, Bangalore 560 064, India.

Estimated Trans-Lamina Cribrosa Pressure Differences in Low-Teen and High-Teen Intraocular Pressure Normal Tension Glaucoma: The Korean National Health and Nutrition Examination Survey.

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Si Hyung Lee

Full Text Available To investigate the association between estimated trans-lamina cribrosa pressure difference (TLCPD and prevalence of normal tension glaucoma (NTG with low-teen and high-teen intraocular pressure (IOP using a population-based study design.A total of 12,743 adults (≥ 40 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES from 2009 to 2012 were included. Using a previously developed formula, cerebrospinal fluid pressure (CSFP in mmHg was estimated as 0.55 × body mass index (kg/m2 + 0.16 × diastolic blood pressure (mmHg-0.18 × age (years-1.91. TLCPD was calculated as IOP-CSFP. The NTG subjects were divided into two groups according to IOP level: low-teen NTG (IOP ≤ 15 mmHg and high-teen NTG (15 mmHg < IOP ≤ 21 mmHg groups. The association between TLCPD and the prevalence of NTG was assessed in the low- and high-teen IOP groups.In the normal population (n = 12,069, the weighted mean estimated CSFP was 11.69 ± 0.04 mmHg and the weighted mean TLCPD 2.31 ± 0.06 mmHg. Significantly higher TLCPD (p < 0.001; 6.48 ± 0.27 mmHg was found in the high-teen NTG compared with the normal group. On the other hand, there was no significant difference in TLCPD between normal and low-teen NTG subjects (p = 0.395; 2.31 ± 0.06 vs. 2.11 ± 0.24 mmHg. Multivariate logistic regression analysis revealed that TLCPD was significantly associated with the prevalence of NTG in the high-teen IOP group (p = 0.006; OR: 1.09; 95% CI: 1.02, 1.15, but not the low-teen IOP group (p = 0.636. Instead, the presence of hypertension was significantly associated with the prevalence of NTG in the low-teen IOP group (p < 0.001; OR: 1.65; 95% CI: 1.26, 2.16.TLCPD was significantly associated with the prevalence of NTG in high-teen IOP subjects, but not low-teen IOP subjects, in whom hypertension may be more closely associated. This study suggests that the underlying mechanisms may differ between low-teen and high-teen NTG patients.

Multiple layers of posttranslational regulation refine circadian clock activity in Arabidopsis.

Science.gov (United States)

Seo, Pil Joon; Mas, Paloma

2014-01-01

The circadian clock is a cellular time-keeper mechanism that regulates biological rhythms with a period of ~24 h. The circadian rhythms in metabolism, physiology, and development are synchronized by environmental cues such as light and temperature. In plants, proper matching of the internal circadian time with the external environment confers fitness advantages on plant survival and propagation. Accordingly, plants have evolved elaborated regulatory mechanisms that precisely control the circadian oscillations. Transcriptional feedback regulation of several clock components has been well characterized over the past years. However, the importance of additional regulatory mechanisms such as chromatin remodeling, protein complexes, protein phosphorylation, and stability is only starting to emerge. The multiple layers of circadian regulation enable plants to properly synchronize with the environmental cycles and to fine-tune the circadian oscillations. This review focuses on the diverse posttranslational events that regulate circadian clock function. We discuss the mechanistic insights explaining how plants articulate a high degree of complexity in their regulatory networks to maintain circadian homeostasis and to generate highly precise waveforms of circadian expression and activity.

Circadian clocks are resounding in peripheral tissues.

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Andrey A Ptitsyn

2006-03-01

Full Text Available Circadian rhythms are prevalent in most organisms. Even the smallest disturbances in the orchestration of circadian gene expression patterns among different tissues can result in functional asynchrony, at the organism level, and may to contribute to a wide range of physiologic disorders. It has been reported that as many as 5%-10% of transcribed genes in peripheral tissues follow a circadian expression pattern. We have conducted a comprehensive study of circadian gene expression on a large dataset representing three different peripheral tissues. The data have been produced in a large-scale microarray experiment covering replicate daily cycles in murine white and brown adipose tissues as well as in liver. We have applied three alternative algorithmic approaches to identify circadian oscillation in time series expression profiles. Analyses of our own data indicate that the expression of at least 7% to 21% of active genes in mouse liver, and in white and brown adipose tissues follow a daily oscillatory pattern. Indeed, analysis of data from other laboratories suggests that the percentage of genes with an oscillatory pattern may approach 50% in the liver. For the rest of the genes, oscillation appears to be obscured by stochastic noise. Our phase classification and computer simulation studies based on multiple datasets indicate no detectable boundary between oscillating and non-oscillating fractions of genes. We conclude that greater attention should be given to the potential influence of circadian mechanisms on any biological pathway related to metabolism and obesity.

Expression of Glutamate and GABA during the Process of Rat Retinal Synaptic Plasticity Induced by Acute High Intraocular Pressure

International Nuclear Information System (INIS)

Zhou, Lihong; Huang, Jufang; Wang, Hui; Luo, Jia; Zeng, Leping; Xiong, Kun; Chen, Dan

2013-01-01

Acute high intraocular pressure (HIOP) can induce plastic changes of retinal synapses during which the expression of the presynaptic marker synaptophysin (SYN) has a distinct spatiotemporal pattern from the inner plexiform layer to the outer plexiform layer. We identified the types of neurotransmitters in the retina that participated in this process and determined the response of these neurotransmitters to HIOP induction. The model of acute HIOP was established by injecting normal saline into the anterior chamber of the rat eye. We found that the number of glutamate-positive cells increased successively from the inner part to the outer part of the retina (from the ganglion cell layer to the inner nuclear layer to the outer nuclear layer) after HIOP, which was similar to the spatiotemporal pattern of SYN expression (internally to externally) following HIOP. However, the distribution and intensity of GABA immunoreactivity in the retina did not change significantly at different survival time post injury and had no direct correlation with SYN expression. Our results suggested that the excitatory neurotransmitter glutamate might participate in the plastic process of retinal synapses following acute HIOP, but no evidence was found for the role of the inhibitory neurotransmitter GABA

Metabolic effects of bariatric surgery in mouse models of circadian disruption.

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Arble, D M; Sandoval, D A; Turek, F W; Woods, S C; Seeley, R J

2015-08-01

Mounting evidence supports a link between circadian disruption and metabolic disease. Humans with circadian disruption (for example, night-shift workers) have an increased risk of obesity and cardiometabolic diseases compared with the non-disrupted population. However, it is unclear whether the obesity and obesity-related disorders associated with circadian disruption respond to therapeutic treatments as well as individuals with other types of obesity. Here, we test the effectiveness of the commonly used bariatric surgical procedure, Vertical Sleeve Gastrectomy (VSG), in mouse models of genetic and environmental circadian disruption. VSG led to a reduction in body weight and fat mass in both Clock(Δ19) mutant and constant-light mouse models (Pdisruption. Interestingly, the decrease in body weight occurred without altering diurnal feeding or activity patterns (P>0.05). Within circadian-disrupted models, VSG also led to improved glucose tolerance and lipid handling (Pdisruption, and that the potent effects of bariatric surgery are orthogonal to circadian biology. However, as the effects of bariatric surgery are independent of circadian disruption, VSG cannot be considered a cure for circadian disruption. These data have important implications for circadian-disrupted obese patients. Moreover, these results reveal new information about the metabolic pathways governing the effects of bariatric surgery as well as of circadian disruption.

Mathematical Models of the Circadian Sleep-Wake Cycle.

Science.gov (United States)

1984-05-01

circadian geber , 97,98 system precision, 4 Form factor Damped oscillators, mutual excitation of, and relationship to ratio of deviations, 37 self-sustainment...rhythms, 5-6 Forced internal desynebronization, by Zeit- incorporation of, into models of circadian geber , 97,98 system precision, 4 Form factor Damped...equation, for modeling of circadian geber phase, and modification by fre- rhythms, 19 quency coefficient, 54,55,56 Oscillatory range, effects of

Plant circadian clocks increase photosynthesis, growth, survival, and competitive advantage.

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Dodd, Antony N; Salathia, Neeraj; Hall, Anthony; Kévei, Eva; Tóth, Réka; Nagy, Ferenc; Hibberd, Julian M; Millar, Andrew J; Webb, Alex A R

2005-07-22

Circadian clocks are believed to confer an advantage to plants, but the nature of that advantage has been unknown. We show that a substantial photosynthetic advantage is conferred by correct matching of the circadian clock period with that of the external light-dark cycle. In wild type and in long- and short-circadian period mutants of Arabidopsis thaliana, plants with a clock period matched to the environment contain more chlorophyll, fix more carbon, grow faster, and survive better than plants with circadian periods differing from their environment. This explains why plants gain advantage from circadian control.

Sensory stimulation for lowering intraocular pressure, improving blood flow to the optic nerve and neuroprotection in primary open-angle glaucoma.

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Rom, Edith

2013-12-01

Primary open-angle glaucoma is a group of optic neuropathies that can lead to irreversible blindness. Sensory stimulation in the form of acupuncture or ear acupressure may contribute to protecting patients from blindness when used as a complementary method to orthodox treatment in the form of drops, laser or surgery. The objective of this article is to provide a narrative overview of the available literature up to July 2012. It summarises reported evidence on the potential beneficial effects of sensory stimulation for glaucoma. Sensory stimulation appears to significantly enhance the pressure-lowering effect of orthodox treatments. Studies suggest that it may also improve blood flow to the eye and optic nerve head. Furthermore, it may play a role in neuroprotection through regulating nerve growth factor and brain-derived neurotrophic factor and their receptors, thereby encouraging the survival pathway in contrast to the pathway to apoptosis. Blood flow and neuroprotection are areas that are not directly influenced by orthodox treatment modalities. Numerous different treatment protocols were used to investigate the effect of sensory stimulation on intraocular pressure, blood flow or neuroprotection of the retina and optic nerve in the animal model and human pilot studies. Objective outcomes were reported to have been evaluated with Goldmann tonometry, Doppler ultrasound techniques and electrophysiology (pattern electroretinography, visually evoked potentials), and supported with histological studies in the animal model. Taken together, reported evidence from these studies strongly suggests that sensory stimulation is worthy of further research.

Effect of topical ophthalmic dorzolamide(2%)-timolol(0.5%) solution and ointment on intraocular pressure in normal horses.

Science.gov (United States)

Tofflemire, Kyle L; Whitley, Elizabeth M; Flinn, Allison M; Dufour, Valerie L; Ben-Shlomo, Gil; Allbaugh, Rachel A; Griggs, Angela N; Peterson, Chimene S; Whitley, David R

2015-11-01

To compare the effect of commercially available solution and compounded ointment formulations of dorzolamide(2%)-timolol(0.5%) on intraocular pressure (IOP) of normal horses. Eighteen clinically normal horses. A randomized, masked prospective design was used with horses divided into two equal groups. One eye of each horse was selected for topical ophthalmic treatment with either 0.2 mL of dorzolamide(2%)-timolol(0.5%) solution or 0.2 g of dorzolamide(2%)-timolol(0.5%) ointment every 12 h for 5 days. The contralateral eye of horses in both groups was untreated. Rebound tonometry was performed every 6 h starting 2 days prior to and ending 2 days after the treatment period. The mean IOP reduction in eyes treated with the solution or ointment formulations was 13%. Untreated eyes in both groups experienced a lesser but still statistically significant reduction in IOP. The IOP values did not return to baseline within 48 h of the last treatment. The commercially available solution and compounded ointment formulations of ophthalmic dorzolamide(2%)-timolol(0.5%) had similar effects on IOP in normal horses. Persistent IOP reduction following cessation of treatment may indicate prolonged drug effect or acclimation of horses to tonometry. © 2014 American College of Veterinary Ophthalmologists.

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

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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.

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

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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.

Protein phosphatase dependent circadian regulation of intermediate-term associative memory

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Michel, Maximilian; Gardner, Jacob S.; Green, Charity L.; Organ, Chelsea L.; Lyons, Lisa C.

2013-01-01

The endogenous circadian clock is a principal factor modulating memory across species. Determining the processes through which the circadian clock modulates memory formation is a key issue in understanding and identifying mechanisms to improve memory. We used the marine mollusk Aplysia californica to investigate circadian modulation of intermediate-term memory (ITM) and the mechanisms through which the circadian clock phase specifically suppresses memory using the operant learning paradigm, l...

Intraocular Surgery in Kyphosis: An Easier Approach

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Karanjit S. Kooner

2013-06-01

Full Text Available We describe a 49-year-old man with advanced kyphosis and dense cataract, who could only recline to about 40° from the vertical axis despite a maximal reverse Trendelenburg position and pillows under the head, neck, shoulders and knees. With a single corneal retraction suture at 6 o'clock, the eye could be rotated horizontally, which enabled the surgeon to perform a complex cataract surgery despite prior glaucoma shunt, posterior synechiae, a small pupil and the need to stain the capsule. As the eye can be brought into any desired position with a retraction suture, patients with kyphosis or other conditions that prevent them from assuming a supine position can still have safe intraocular procedures. This maneuver reduces the need to tilt patients to an uncomfortable position that may cause pain, increased breathing difficulty and elevated posterior vitreous pressure.

Evaluation of circadian phenotypes utilizing fibroblasts from patients with circadian rhythm sleep disorders.

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Hida, A; Ohsawa, Y; Kitamura, S; Nakazaki, K; Ayabe, N; Motomura, Y; Matsui, K; Kobayashi, M; Usui, A; Inoue, Y; Kusanagi, H; Kamei, Y; Mishima, K

2017-04-25

We evaluated the circadian phenotypes of patients with delayed sleep-wake phase disorder (DSWPD) and non-24-hour sleep-wake rhythm disorder (N24SWD), two different circadian rhythm sleep disorders (CRSDs) by measuring clock gene expression rhythms in fibroblast cells derived from individual patients. Bmal1-luciferase (Bmal1-luc) expression rhythms were measured in the primary fibroblast cells derived from skin biopsy samples of patients with DSWPD and N24SWD, as well as control subjects. The period length of the Bmal1-luc rhythm (in vitro period) was distributed normally and was 22.80±0.47 (mean±s.d.) h in control-derived fibroblasts. The in vitro periods in DSWPD-derived fibroblasts and N24SWD-derived fibroblasts were 22.67±0.67 h and 23.18±0.70 h, respectively. The N24SWD group showed a significantly longer in vitro period than did the control or DSWPD group. Furthermore, in vitro period was associated with response to chronotherapy in the N24SWD group. Longer in vitro periods were observed in the non-responders (mean±s.d.: 23.59±0.89 h) compared with the responders (mean±s.d.: 22.97±0.47 h) in the N24SWD group. Our results indicate that prolonged circadian periods contribute to the onset and poor treatment outcome of N24SWD. In vitro rhythm assays could be useful for predicting circadian phenotypes and clinical prognosis in patients with CRSDs.

Clinical research of phacoemulsification with posterior chamber intraocular lens implantation for glaucoma with different goniosynechia ranges

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Qing-Yu Li

2016-02-01

Full Text Available AIM:To study the effect of phacoemulsification with posterior chamber intraocular lens implantation to treat glaucoma with different angle-closure range, which may provide a better way to treat the angle-closure glaucoma.METHODS:There were 47 cases(54 eyeswith angle-closure glaucoma, and all of them underwent phacoemulsification and posterior chamber intraocular lens implantation. According to the range of goniosynechia, these patients were divided into three groups:the eyes with the range of goniosynechia≤1/2 were group A(13 eyes; the eyes with 1/23/4 were group C(23 eyes. We observed the status of anterior chamber angle and the intraocular pressure(IOPof the three groups at 2wk after operations. RESULTS:Compared to the preoperative condition, the IOP of the three groups at 2wk after operations decreased significantly. The IOP reductions of group B and C were more significant than that of group A, and the differences were significant(PPP3/4 appeared in group B; in group C, there were 5 eyes with goniosynechia>3/4, 1 eye with disappeared anterior chamber, 3 eyes with corneal edema, 1 eye with choroidal hemorrhage. The differences of postoperative complication rate among the three groups was statistically significant(PPCONCLUSION:For patients with angle closure glaucoma who have mild to moderate goniosynechia, phacoemulsification with posterior chamber intraocular lens implantation is an effective way. After operations, their closed anterior angle reopened. But to the patients with severe adhesions, there are more complications after operations, especially the glaucoma may reoccur.

"Time sweet time": circadian characterization of galectin-1 null mice

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Rabinovich Gabriel A

2010-04-01

Full Text Available Abstract Background Recent evidence suggests a two-way interaction between the immune and circadian systems. Circadian control of immune factors, as well as the effect of immunological variables on circadian rhythms, might be key elements in both physiological and pathological responses to the environment. Among these relevant factors, galectin-1 is a member of a family of evolutionarily-conserved glycan-binding proteins with both extracellular and intracellular effects, playing important roles in immune cell processes and inflammatory responses. Many of these actions have been studied through the use of mice with a null mutation in the galectin-1 (Lgals1 gene. To further analyze the role of endogenous galectin-1 in vivo, we aimed to characterize the circadian behavior of galectin-1 null (Lgals1-/- mice. Methods We analyzed wheel-running activity in light-dark conditions, constant darkness, phase responses to light pulses (LP at circadian time 15, and reentrainment to 6 hour shifts in light-dark schedule in wild-type (WT and Lgals1-/- mice. Results We found significant differences in free-running period, which was longer in mutant than in WT mice (24.02 vs 23.57 h, p alpha (14.88 vs. 12.35 circadian h, p Conclusions Given the effect of a null mutation on circadian period and entrainment, we indicate that galectin-1 could be involved in the regulation of murine circadian rhythmicity. This is the first study implicating galectin-1 in the mammalian circadian system.

Emergence of noise-induced oscillations in the central circadian pacemaker.

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Caroline H Ko

2010-10-01

Full Text Available Bmal1 is an essential transcriptional activator within the mammalian circadian clock. We report here that the suprachiasmatic nucleus (SCN of Bmal1-null mutant mice, unexpectedly, generates stochastic oscillations with periods that overlap the circadian range. Dissociated SCN neurons expressed fluctuating levels of PER2 detected by bioluminescence imaging but could not generate circadian oscillations intrinsically. Inhibition of intercellular communication or cyclic-AMP signaling in SCN slices, which provide a positive feed-forward signal to drive the intracellular negative feedback loop, abolished the stochastic oscillations. Propagation of this feed-forward signal between SCN neurons then promotes quasi-circadian oscillations that arise as an emergent property of the SCN network. Experimental analysis and mathematical modeling argue that both intercellular coupling and molecular noise are required for the stochastic rhythms, providing a novel biological example of noise-induced oscillations. The emergence of stochastic circadian oscillations from the SCN network in the absence of cell-autonomous circadian oscillatory function highlights a previously unrecognized level of circadian organization.

Neural Mechanisms of Circadian Regulation of Natural and Drug Reward

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Lauren M. DePoy

2017-01-01

Full Text Available Circadian rhythms are endogenously generated near 24-hour variations of physiological and behavioral functions. In humans, disruptions to the circadian system are associated with negative health outcomes, including metabolic, immune, and psychiatric diseases, such as addiction. Animal models suggest bidirectional relationships between the circadian system and drugs of abuse, whereby desynchrony, misalignment, or disruption may promote vulnerability to drug use and the transition to addiction, while exposure to drugs of abuse may entrain, disrupt, or perturb the circadian timing system. Recent evidence suggests natural (i.e., food and drug rewards may influence overlapping neural circuitry, and the circadian system may modulate the physiological and behavioral responses to these stimuli. Environmental disruptions, such as shifting schedules or shorter/longer days, influence food and drug intake, and certain mutations of circadian genes that control cellular rhythms are associated with altered behavioral reward. We highlight the more recent findings associating circadian rhythms to reward function, linking environmental and genetic evidence to natural and drug reward and related neural circuitry.

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

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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

Optic nerve head and intraocular pressure in the guinea pig eye.

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Ostrin, Lisa A; Wildsoet, Christine F

2016-05-01

The guinea pig is becoming an increasingly popular model for studying human myopia, which carries an increased risk of glaucoma. As a step towards understanding this association, this study sought to characterize the normal, developmental intraocular pressure (IOP) profiles, as well as the anatomy of the optic nerve head (ONH) and adjacent sclera of young guinea pigs. IOP was tracked in pigmented guinea pigs up to 3 months of age. One guinea pig was imaged in vivo with OCT and one with a fundus camera. The eyes of pigmented and albino guinea pigs (ages 2 months) were enucleated and sections from the posterior segment, including the ONH and surrounding sclera, processed for histological analyses - either hematoxylin and eosin (H&E) staining of paraffin embedded, sectioned tissue (n = 1), or cryostat sectioned tissue, processed for immunohistochemistry (n = 3), using primary antibodies against collagen types I-V, elastin, fibronectin and glial fibrillary acidic protein (GFAP). Transmission and scanning electron microscopy (TEM, SEM) studies of ONHs were also undertaken (n = 2 & 5 respectively). Mean IOPs ranged from 17.33 to 22.7 mmHg, increasing slightly across the age range studied, and the IOPs of individual animals also exhibited diurnal variations, peaking in the early morning (mean of 25.8, mmHg, ∼9 am), and decreasing across the day. H&E-stained sections showed retinal ganglion cell axons organized into fascicles in the prelaminar and laminar region of the ONHs, with immunostained sections revealing collagen types I, III, IV and V, as well as elastin, GFAP and fibronectin in the ONHs. SEM revealed a well-defined lamina cribrosa (LC), with radially-oriented collagen beams. TEM revealed collagen fibrils surrounding non-myelinated nerve fiber bundles in the LC region, with myelination and decreased collagen posterior to the LC. The adjacent sclera comprised mainly crimped collagen fibers in a crisscross arrangement. Both the sclera and LC were

Intraocular pressure and ocular pulse amplitude using dynamic contour tonometry and contact lens tonometry.

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Hoffmann, Esther M; Grus, Franz-H; Pfeiffer, Norbert

2004-03-23

The new Ocular Dynamic Contour Tonometer (DCT), investigational device supplied by SMT (Swiss Microtechnology AG, Switzerland) allows simultaneous recording of intraocular pressure (IOP) and ocular pulse amplitude (OPA). It was the aim of this study to compare the IOP results of this new device with Goldmann tonometry. Furthermore, IOP and OPA measured with the new slitlamp-mounted DCT were compared to the IOP and OPA measured with the hand-held SmartLens,a gonioscopic contact lens tonometer (ODC Ophthalmic Development Company AG, Switzerland). Nineteen healthy subjects were included in this study. IOP was determined by three consecutive measurements with each of the DCT, SmartLens, and Goldmann tonometer. Furthermore, OPA was measured three times consecutively by DCT and SmartLens. No difference (P = 0.09) was found between the IOP values by means of DCT (mean: 16.6 mm Hg, median: 15.33 mm Hg, SD: +/- 4.04 mm Hg) and Goldmann tonometry (mean: 16.17 mm Hg, median: 15.33 mm Hg, SD: +/- 4.03 mm Hg). The IOP values of SmartLens (mean: 20.25 mm Hg, median: 19.00 mm Hg, SD: +/- 4.96 mm Hg) were significantly higher (P = 0.0008) both from Goldmann tonometry and DCT. The OPA values of the DCT (mean: 3.08 mm Hg, SD: +/- 0.92 mm Hg) were significantly lower (P = 0.0003) than those obtained by SmartLens (mean: 3.92 mm Hg, SD: +/- 0.83 mm Hg). DCT was equivalent to Goldmann applanation tonometry in measurement of IOP in a small group of normal subjects. In contrast, SmartLens (contact lens tonometry) gave IOP readings that were significantly higher compared with Goldmann applanation tonometer readings. Both devices, DCT and SmartLens provide the measurement of OPA which could be helpful e.g. for the management of glaucoma.