WorldWideScience

Sample records for lens vitreous body

  1. Effects of lens extirpation with anterior vitrectomy on vitreous three-dimensional mesh structure

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    2017-06-01

    Full Text Available AIM: To investigate the changes in vitreous gel structure after lens extirpation combined with anterior vitrectomy in rabbit eyes. METHODS: Twenty-eight chinchilla rabbits were divided into three groups. The control group (Group I included 16 eyes from eight rabbits who did not receive any treatment. Group II included 20 eyes from 10 rabbits that underwent lens aspiration only. Group III included 20 eyes from 10 rabbits that underwent lens aspiration combined with posterior capsulotomy and anterior vitrectomy. Eyes were harvested on the 30th and 60th day postoperatively, respectively. Changes in vitreous gel stretch length due to gravity and the rate of vitreous liquefaction were observed. The collagen content in the vitreous body was examined using the L-hydroxyproline test. Electronic microscopic images were obtained from each eyeball. RESULTS: On both the 30th and 60th day postoperatively, the vitreous gel length of group III was significantly shorter than group I and group II (P<0.05, while the rate of liquefaction of the vitreous body in group III was significantly higher than group I and group II (P<0.05. The collagen content in group III was also higher than that in group I and group II (P<0.05. CONCLUSION: Loss of vitreous gel mass is more likely to occur in the eyes of rabbits receiving anterior vitrectomy. Lensectomy combined with anterior vitrectomy may damage the stable three-dimensional mesh structure of collagen, which could aggravate vitreous gel liquefaction.

  2. Sectioning a luxated intraocular lens inside the vitreous cavity.

    Science.gov (United States)

    Vilaplana, Daniel; Pazos, Marta

    2013-07-01

    We describe a new technique for sectioning an intraocular lens (IOL) inside the vitreous cavity. The IOL had a broken haptic and was accidentally luxated after a complicated cataract surgery with posterior capsule rupture. The primary indication to cut the IOL in half inside the vitreous cavity is to preserve the anterior capsule integrity, especially in a small-sized capsulotomy, allowing subsequent implantation of a new IOL in the sulcus with the optical zone captured in the capsulorhexis. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. [Persistence of the primordial vitreous body and buphthalmos].

    Science.gov (United States)

    Cernea, P; Simionescu, C; Bosun, I

    1995-01-01

    Persistence of the hyperplasic primordial vitreous body is determined by a deletion of embryonal development of the vitreous body and of the hyaloid vascular system. Infant aged 3.5 years presents persistence of primordial vitreous body with crystalline dislocation in the camera aquosa and secondary buphthalmos of the left eye and microphthalmos with dislocation of the crystalline in the vitreous body of the right eye. At the back of the right eye we noticed a whitish mass, richly vascularized with vestiges from the hyaloid artery, but the posterior half of the vitreous cavity is filled with microscopic blood; the fibrovascular membrane is made of conjunctive tissue set in parallel layers and vessels with macrolipophagic degeneration. Microscopic investigation of retina reveals glial hyperplasia zones in the neighbourhood of the vitreous body. In the present paper the authors show the persistence of the primordial vitreous body in the left eye and bilateral dislocation of the crystalline, revealing multiple ocular malformations.

  4. Non-destructive examination system of vitreous body

    Science.gov (United States)

    Shibata, Takuma; Gong, Jin; Watanabe, Yosuke; Kabir, M. Hasnat; Masato, Makino; Furukawa, Hidemitsu; Nishitsuka, Koichi

    2014-04-01

    Eyeball plays a quite important role in acquiring the vision. Vitreous body occupies the largest part of the eyeball and consists of biological, elastic, transparent, gel materials. In the present medical examination, the non-destructive examination method of the vitreous body has not been well established. Here, we focus on an application of dynamic light scattering to this topic. We tried to apply our lab-made apparatus, scanning microscopic light scattering (SMILS), which was specially designed for observing the nanometer-scale network structure in gel materials. In order to examine the vitreous body using SMILS method, a commercial apparatus, nano Partica (Horiba Co. Ltd.) was also customized. We analyzed vitreous body using both the SMILS and the customized nano Partica. We successfully examined the vitreous bodies of healthy pigs in non-destructive way.

  5. Vitreous Humor Changes Expression of Iron-Handling Proteins in Lens Epithelial Cells

    Science.gov (United States)

    Goralska, Malgorzata; Fleisher, Lloyd N.; McGahan, M. Christine

    2017-01-01

    Purpose In humans, vitrectomy is associated with development of nuclear cataracts. Iron catalyzes free radical formation causing oxidative damage, which is implicated in cataract formation. This study was designed to determine if vitreous humor, which can initiate differentiation of lens epithelial cells, would have an effect on iron-handling proteins. Methods Cultured canine lens epithelial cells were treated with collected canine vitreous humor. Lysates of treated and control cells were separated by SDS-PAGE. Ferritin H- and L-chains, transferrin receptor 1, and aquaporin 0 were immunodetected and quantitated with specific antibodies. Morphologic changes in treated cells were assessed. Results Treatment of lens epithelial cells with a 33% (vol/vol) solution of vitreous humor changed the morphology of lens cells and induced expression of aquaporin 0, a marker of fiber cell differentiation that was undetectable in control cells. Treatment did not modify the size of iron-handling proteins but significantly increased content of ferritin from 2.9- to 8.8-fold over control and decreased levels of transferrin receptor by 37% to 59%. Conclusions Vitreous humor may significantly limit iron uptake by transferrin/transferrin receptor pathway, and by increasing ferritin levels could profoundly increase the iron-storage capacity of ferritin in lens cells. Vitreous humor may play a significant protective role against iron-catalyzed oxidative damage of lens epithelial cells and therefore in the formation of cataracts. PMID:28245299

  6. Intra-ocular lens implantation after vitreous loss.

    Directory of Open Access Journals (Sweden)

    Shah N

    1991-10-01

    Full Text Available Vitreous loss is a dreaded complication of cataract surgery, especially so with IOL implant which then may have to be abandoned. Thirty three cases of IOL implants, either anterior chamber or posterior chamber, after vitreous loss done in the past 3 years were studied. Of these, 18 (55% had a final visual acuity of 6/18 or better and none was worse than 6/60. The postoperative complications and findings and a review of literature are discussed.

  7. A SEM-correlation of the anatomy of the vitreous body: making visible the invisible.

    Science.gov (United States)

    Jongebloed, W L; Humalda, D; Worst, J F

    1986-12-30

    The naked human vitreous (sclera, iris and cornea removed) suspended in water does not reveal inner structures. After ink injection into the vitreous, the presence of different compartments and the existence of cisterns becomes evident. A concept of the internal system of cisterns is given on the basis of stereoscopic-lightmicroscopic images. An attempt is made to correlate images of the complete vitreous body, obtained with a stereo-lightmicroscope, with images of segments of cisternal walls produced with a scanning electron-microscope (SEM). A comparison is made between SEM-images of the vitreous bodies of human and rabbit eyes.

  8. COMPARATIVE ANATOMY OF THE VITREOUS BODY IN RHESUS-MONKEYS AND MAN

    NARCIS (Netherlands)

    WORST, JGF; LOS, LI

    1992-01-01

    In the isolated unfixed vitreous body a structural organization can be visualized by slitlamp microscopy or by an ink-injection technique. We discuss the observations on human and rhesus monkey (Macaca mulatta) vitreous bodies using the ink-injection technique. Advantages and disadvantages of this

  9. [Buffering capacity of the vitreous body in aggressive posterior retinopathy of prematurity].

    Science.gov (United States)

    Amkhanitskaia, L I; Sidorenko, E I; Nikolaeva, G V; Kuznetsova, Iu D

    2014-01-01

    To investigate the role of vitreous body changes in the pathogenesis of aggressive posterior retinopathy of prematurity. The study included 60 children with stage 4-5 retinopathy of prematurity demonstrating either classical or aggressive posterior form of progression. In all cases vitreous samples for laboratory testing were taken during surgery. The study showed that aggressive posterior retinopathy of prematurity is associated with more significant metabolic changes in comparison with classical form of the disease. The degree of biochemical imbalance of the vitreous appeared directly related to the stage of the disease, which was determined by the type and extent of retinal detachment. Volcano-shaped retinal detachment with intensive exudation within the posterior eye segment is considered the most severe variant of aggressive posterior retinopathy of prematurity. Aggressive posterior retinopathy of prematurity is characterized by substantial disturbance of metabolism of the vitreous body, which contributes to exudation and proliferation, thus aggravating the course of the disease and worsening the prognosis.

  10. Supracapsular glued intraocular lens in progressive subluxated cataracts: Technique to retain an intact vitreous face.

    Science.gov (United States)

    Jacob, Soosan; Narasimhan, Smita; Agarwal, Amar; Mazzotta, Cosimo; Rechichi, Miguel; Agarwal, Athiya

    2017-03-01

    We describe a technique to prevent late intraocular lens (IOL) subluxation and dislocation that can be associated with progressive zonulopathy. Supracapsular glued IOL fixation is done to retain an intact anterior hyaloid face and avoid vitreous disturbance while providing stable long-term IOL fixation. Phacoemulsification is followed by glued IOL implantation above intact anterior and posterior capsules. Sclerotomies are created ab interno in a supracapsular plane under diametrically opposite lamellar scleral flaps without entering the vitreous cavity. Haptics are externalized in the supracapsular plane and tucked into intrascleral tunnels. Intraoperative or postoperative posterior capsulorhexis or capsulotomy and anterior capsule relaxing cuts can prevent capsule phimosis. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  11. Morphology and accommodative function of the vitreous zonule in human and monkey eyes.

    Science.gov (United States)

    Lütjen-Drecoll, Elke; Kaufman, Paul L; Wasielewski, Rainer; Ting-Li, Lin; Croft, Mary Ann

    2010-03-01

    To explore the attachments of the posterior zonule and vitreous in relation to accommodation and presbyopia in monkeys and humans. Novel scanning electron microscopy (SEM) and ultrasound biomicroscopy (UBM) techniques were used to visualize the anterior, intermediate, and posterior vitreous zonule and their connections to the ciliary body, vitreous membrane, lens capsule, and ora serrata, and to characterize their age-related changes and correlate them with loss of accommodative forward movement of the ciliary body. alpha-Chymotrypsin was used focally to lyse the vitreous zonule and determine the effect on movement of the accommodative apparatus in monkeys. The vitreous attached to the peripheral lens capsule and the ora serrata directly. The pars plana zonule and the posterior tines of the anterior zonule were separated from the vitreous membrane except for strategically placed attachments, collectively termed the vitreous zonule, that may modulate and smooth the forward and backward movements of the entire system. Age-dependent changes in these relationships correlated significantly with loss of accommodative amplitude. Lysis of the intermediate vitreous zonule partially restored accommodative movement. The vitreous zonule system may help to smoothly translate to the lens the driving forces of accommodation and disaccommodation generated by the ciliary muscle, while maintaining visual focus and protecting the lens capsule and ora serrata from acute tractional forces. Stiffening of the vitreous zonular system may contribute to age-related loss of accommodation and offer a therapeutic target for presbyopia.

  12. Stability of endogenous GHB in vitreous humor vs peripheral blood in dead bodies.

    Science.gov (United States)

    Busardò, Francesco Paolo; Mannocchi, Giulio; Giorgetti, Raffaele; Pellegrini, Manuela; Baglio, Giovanni; Zaami, Simona; Marinelli, Enrico; Pichini, Simona

    2017-05-01

    For the first time, the stability of GHB was tested in post-mortem peripheral blood and vitreous humor samples, collected from 22 dead bodies at two different times: at the external body examination at the place of death and then during autopsy. An ad hoc method for the detection and quantification of GHB in vitreous humor by gas chromatography coupled to mass spectrometry (GC-MS) was developed and validated, with a good linearity between 0.1 and 50μg/mL (r 2 =0.991) and a precision and accuracy always better than 10% and an analytical recovery higher than 90%. The geometric mean of GHB concentration in the 22 peripheral blood samples at t 0 was: 3.6μg/mL (95% CI: 2.3-5.9μg/mL) and at t 1 it was 7.4μg/mL (95% CI: 5.0-10.9μg/mL); that of GHB in the 22 vitreous humor at t 0 was: 2.5μg/mL (95% CI: 1.5-4.1μg/mL) and at t 1 it was 3.0μg/mL (95% CI: 1.9-4.8μg/mL). There was no significant difference between the GHB concentrations in vitreous humor and peripheral blood at t 0 in all the samples (p>0.10). Conversely at t 1 , the increase of GHB in the peripheral blood was significantly increased by a 102% (range: 86-120%) (phumor only a slight increase by 19% was observed (range: 16-21%) (p>0.05 vs t 0 ). Finally at t 1 , GHB values in the two matrices were statistically different, being that of peripheral blood higher (phumor as a more stable alternative matrix in comparison to peripheral blood for the post-mortem determination of endogenous GHB. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. SURGICAL INTERVENTION AND ACCOMMODATIVE RESPONSES: I. CENTRIPETAL CILIARY BODY, CAPSULE AND LENS MOVEMENT IN RHESUS MONKEYS OF VARYING AGE

    Science.gov (United States)

    Croft, Mary Ann; Mcdonald, Jared P.; James, Rebecca J.; Heatley, Gregg A.; Lin, Ting-Li; Lütjen-Drecoll, Elke; Kaufman, Paul L.

    2009-01-01

    Purpose To determine how surgically altering the normal relationship between the lens and the ciliary body in rhesus monkeys affects centripetal ciliary body and lens movement. Methods In 18 rhesus monkey eyes (aged 6–27 years), accommodation was induced before and after surgery by electrical stimulation of the Edinger-Westphal (E–W) nucleus. Accommodative amplitude was measured by coincidence refractometry. Goniovideography was performed before and after intra- and extra-capsular lens extraction (ICLE, ECLE) and anterior regional zonulolysis. Centripetal lens/capsule movements, centripetal ciliary process (CP) movements, and circumlental space were measured by computerized image analysis of the goniovideography images. Results Centripetal accommodative CP and capsule movement increased in velocity and amplitude post-ECLE compared to pre-ECLE regardless of age (n=5). The presence of the lens substance retarded capsule movement by ~21% in the young eyes and by ~62% in the older eyes. Post-ICLE compared to pre-ICLE centripetal accommodative CP movement was dampened in all eyes in which the anterior vitreous was disturbed (n=7), but not in eyes in which the anterior vitreous was left intact (n=2). Following anterior regional zonulolysis (n=4), lens position shifted toward the lysed quadrant during accommodation. Conclusions The presence of the lens substance, capsule zonular attachments, and Wiegers ligament may play a role in centripetal CP movement. The capsule is still capable of centripetal movement in the older eye (although at a reduced capacity) and may have the ability to produce ~6 diopters of accommodation in the presence of a normal young crystalline lens or a similar surrogate. PMID:18552393

  14. Characterization of the vitreous body of the human eye using a cyanine dye as a spectral and fluorescent probe

    Science.gov (United States)

    Panova, Ina G.; Tatikolov, Alexander S.

    2009-02-01

    We used one of cyanine dyes as a spectral and fluorescent probe in the study of the composition of the extracellular matrix of the human eye (its vitreous body). Owing to the unique ability of the dye to bind to collagens and human serum albumin, we revealed the simultaneous presence of both types of biomacromolecules in the vitreous body. The formation of the dye complex with human serum albumin leads to appearance of a long-wavelength absorption band (~612 nm) and a steep rise of fluorescence, whereas in the presence of collagens the dye forms J-aggregates with a longer-wavelength absorption band (640-660 nm) and moderate fluorescence. In this work we studied the composition of the human fetus vitreous body and its dynamics from 9 to 31 gestation weeks. On the basis of the data obtained by this method, we may assume that albumin, being a carrier protein, probably provides the vitreous body and surrounding tissues with necessary growth factors, hormones, lipids, vitamins, and some other biomolecules. The data show that the dye is promising not only for study of albumin functions in eye development, but also for characterization of some eye diseases and for analysis of other extracellular media.

  15. Age-related liquefaction of the human vitreous body : LM and TEM evaluation of the role of proteoglycans and collagen

    NARCIS (Netherlands)

    Los, Leonoor I.; van der Worp, Roelofje J; van Luyn, Marja J. A.; Hooymans, Johanna M. M.

    PURPOSE. To evaluate morphologic aspects of age-related liquefaction of the human vitreous body by fight and electron microscopy to provide a basis from which future studies directed at the pathogenesis of this phenomenon can be undertaken. The study focuses on changes in fibrillar Collagen and

  16. [Structure of the vitreous body over areas with lattice degeneration of the retina (author's transl)].

    Science.gov (United States)

    Slezak, H

    1975-12-04

    The clinical examination of the vitreous in the extreme fundus periphery is difficult; therefore only very little was known up to now about the relations of the posterior limiting membrane of the vitreous and the preretinal tract to retinal lattice degenerations arranged parallel to the ora serrata in several rows. There will be reports of new findings gained by depression biomicroscopy.

  17. Changes in Oxygen Partial Pressure in the Vitreous Body and Arterial Blood of Rabbits Depending on Oxygen Concentration in Inspired Mixture.

    Science.gov (United States)

    Amkhanitskaya, L I; Nikolaeva, G V; Sokolova, N A

    2015-07-01

    We demonstrated that the vitreous body of one-month-old rabbits becomes a "reservoir" for storage and accumulation of oxygen after exposure to additional oxygenation of the organism (O2 concentrations in inspired gas mixture were 40, 60, 85, and 99%). The higher was O2 concentration in inspired mixture, the higher was oxygen saturation of the blood and vitreous body. O2 concentration of 40% was relatively safe for eye tissues. O2 concentration >60% induced oxygen accumulation in the vitreous body, which can be a provoking factor for the development of oxygen-induced pathologies.

  18. Organization of the rabbit vitreous body : Lamellae, Cloquet's channel and a novel structure, the 'alae canalis Cloqueti'

    NARCIS (Netherlands)

    Los, LI; van Luyn, MJA; Nieuwenhuis, P

    Even though the rabbit is a frequently used animal model for studies on Vitreous function and pathobiology, data on the structural organization of the rabbit Vitreous are scarce. The aim of the present study is to give a detailed description of rabbit vitreous structure in order to provide a basis

  19. Vitreous cinematography in the study of vitreoretinal diseases.

    Science.gov (United States)

    Trempe, C L; Takahashi, M; Freeman, H M

    1981-07-01

    A new technique of vitreous cinematography involves scanning of the vitreous cavity using optical sections to provide objective, reproducible information on the dynamics of the posterior vitreous and vitreoretinal relationships. Using a newly developed preset lens (El Bayadi-Kajiura lens), this technique makes it possible to document an entire optical section of the posterior vitreous. This is done by mechanically displacing the vitreous so that maximum reflectivity can be obtained from the vitreous gel. This article describes the technique and presents clinical examples documenting complete and incomplete vitreous detachment in normal eyes, Cloquet's canal associated with an optic disc pit, vitreous traction associated with a lamellar hole in an area of preretinal macular fibrosis, and vitreous traction at the anterior flap of a retinal break.

  20. Whole vitreous humor dissection for vitreodynamic analysis.

    Science.gov (United States)

    Murali, Karthik; Kashani, Amir H; Humayun, Mark S

    2015-05-24

    The authors propose an effective technique to isolate whole, intact vitreous core and cortex from post mortem enucleated porcine eyes. While previous studies have shown the results of such dissections, the detailed steps have not been described, precluding researchers outside the field from replicating their methods. Other studies harvest vitreous either through aspiration, which does not maintain the vitreous structure anatomy, or through partial dissection, which only isolates the vitreous core. The proposed method isolates the whole vitreous body, with the vitreous core and cortex intact, while maintaining vitreous anatomy and structural integrity. In this method, a full thickness scleral flap in an enucleated porcine eye is first created and through this, the choroid tissue can be separated from the sclera. The scleral flap is then expanded and the choroid is completely separated from the sclera. Finally the choroid-retina tissue is peeled off the vitreous to leave an isolated intact vitreous body. The proposed vitreous dissection technique can be used to study physical properties of the vitreous humor. In particular, this method has significance for experimental studies involving drug delivery, vitreo-retinal oxygen transport, and intraocular convection.

  1. A direct contact between astrocyte and vitreous body is possible in the rabbit eye due to discontinuities in the basement membrane of the retinal inner limiting membrane

    Directory of Open Access Journals (Sweden)

    A. Haddad

    2003-02-01

    Full Text Available Different from most mammalian species, the optic nerve of the rabbit eye is initially formed inside the retina where myelination of the axons of the ganglion cells starts and vascularization occurs. Astrocytes are confined to these regions. The aforementioned nerve fibers known as medullated nerve fibers form two bundles that may be identified with the naked eye. The blood vessels run on the inner surface of these nerve fiber bundles (epivascularization and, accordingly, the accompanying astrocytes lie mostly facing the vitreous body from which they are separated only by the inner limiting membrane of the retina. The arrangement of the astrocytes around blood vessels leads to the formation of structures known as glial tufts. Fragments (N = 3 or whole pieces (N = 3 of the medullated nerve fiber region of three-month-old male rabbits (Orictolagus cuniculus were fixed in glutaraldehyde followed by osmium tetroxide, and their thin sections were examined with a transmission electron microscope. Randomly located discontinuities (up to a few micrometers long of the basement membrane of the inner limiting membrane of the retina were observed in the glial tufts. As a consequence, a direct contact between the astrocyte plasma membrane and vitreous elements was demonstrated, making possible functional interactions such as macromolecular exchanges between this glial cell type and the components of the vitreous body.

  2. Intraocular lens dislocation after whole-body vibration.

    Science.gov (United States)

    Vela, José I; Andreu, David; Díaz-Cascajosa, Jesús; Buil, José A

    2010-10-01

    We present 2 cases of intraocular lens (IOL) dislocation that appeared shortly after the patients exercised on a vibration platform. The first patient was a 71-year-old woman who presented with lens subluxation in her right eye and a complete posterior IOL dislocation in her left eye. The second case was a 62-year-old woman who presented with unilateral IOL dislocation within the capsular bag in her right eye. Timing from IOL implantation to dislocation was approximately 6 years and 4 years, respectively. Pars plana vitrectomy with removal of the dislocated IOL was performed in both patients. Whole-body vibration training has become increasingly popular as a form of exercise training. It reportedly may provide benefits in physical function and in some diseases, especially in older people. However, evidence-based protocols ensuring safety and efficacy in this population are lacking. We discuss vibration as a cause of late IOL dislocation. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Regional distribution of phospholipids in porcine vitreous humor.

    Science.gov (United States)

    Schnepf, Abigail; Yappert, Marta Cecilia; Borchman, Douglas

    2017-07-01

    This project explores the regional phospholipid distribution in porcine vitreous humor, retina, and lens. Matrix-assisted laser desorption mass spectrometry has been used previously to image lipids, proteins, and other metabolites in retinas and lenses. However, the regional composition of phospholipids in vitreous humors is not known. To address this issue, we have applied this mass spectral method to explore the regional phospholipid distribution in porcine vitreous humor both ex-situ and in-vitro. To establish the possible source(s) of phospholipids in the vitreous humor, compositional studies of the lens and retina were also pursued. Due to the overall low levels of phospholipids in vitreous humor, it was necessary to optimize the experimental approaches for ex-situ and in-vitro studies. The sensitivity observed in the spectra of methanol extracts from the lens and retina was higher than that for methanol:chloroform extracts, but the compositional trends were the same. A fourfold improvement in sensitivity was observed in the analysis of vitreous humor extracts obtained with the Bligh and Dyer protocol relative to the other two extraction methods. For ex-situ studies, the 'stamp method' with para-nitroaniline as the matrix was chosen. Throughout the vitreous humor, phosphatidylcholines were the most abundant phospholipids. In-vitro results showed higher relative levels of phospholipids compared to the 'stamp' method. However, more details in the regional phospholipid distribution were provided by the ex-situ approach. Both in-vitro and ex-situ results indicated higher levels of phospholipids in the posterior vitreous region, followed by the anterior and central regions. The posterior region contained more unsaturated species whereas more saturated phospholipids were detected in the anterior region. The observed trends suggest that the phospholipids detected in the posterior vitreous humor migrate from the retina and associated vasculature while those present in

  4. Eye rotation induced dynamics of a Newtonian fluid within the vitreous cavity: the effect of the chamber shape

    International Nuclear Information System (INIS)

    Stocchino, Alessandro; Repetto, Rodolfo; Cafferata, Chiara

    2007-01-01

    The dynamics of the vitreous body induced by eye rotations is studied experimentally. In particular, we consider the case in which the vitreous cavity is filled by a Newtonian fluid, either because the vitreous is liquefied or because it has been replaced, after vitrectomy, by a viscous fluid. We employ a rigid Perspex container which models, in a magnified scale, the vitreous cavity of the human eye. The shape of the cavity closely resembles that of the real vitreous chamber; in particular, the anterior part of the container is concave in order to model the presence of the eye lens. The container is filled with glycerol and is mounted on the shaft of a computer-controlled motor which rotates according to a periodic time law. PIV (particle image velocimetry) measurements are taken on the equatorial plane orthogonal to the axis of rotation. The experimental measurements show that the velocity field is strongly influenced by the deformed geometry of the domain. In particular, the formation of a vortex in the vicinity of the lens, which migrates in time towards the core of the domain, is invariably observed. The vortex path is tracked in time by means of a vortex identification technique and it is found that it is significantly influenced by the Womersley number of the flow. Particle trajectories are computed from the PIV measurements. Particles initially located at different positions on the equatorial horizontal plane (perpendicular to the axis of rotation) tend to concentrate in narrow regions adjacent to the lens, thus suggesting the existence, in such regions, of a vertical fluid ejection. Such a strong flow three-dimensionality, which is essentially induced by the irregular shape of the domain, may play a significant role in the mixing processes taking place inside the eye globe. The tangential stresses acting on the rigid boundary of the domain are also computed from the experimental measurements showing that regions subject to particularly intense stresses

  5. The effects of aging vitreous on contrast sensitivity function.

    Science.gov (United States)

    Garcia, Giancarlo A; Khoshnevis, Matin; Yee, Kenneth M P; Nguyen, Justin H; Nguyen-Cuu, Jeannie; Sadun, Alfredo A; Sebag, J

    2018-05-01

    Contrast sensitivity function (CSF) declines with age. When unassociated with cataracts, this is hypothesized to be due to macular ganglion cell complex (GCC) thinning. However, other studies found associations with increased vitreous echodensity and posterior vitreous detachment (PVD). We investigate the relationship between CSF, vitreous echodensity, PVD, and GCC thickness as related to age in the same subjects. Age, CSF (Weber index: %W), vitreous echodensity (quantitative ultrasonography [QUS]), lens status (phakia or pseudophakia), best-corrected visual acuity (BCVA), and GCC thickness (SD-OCT) were evaluated in 57 eyes of 57 subjects with (n = 32, mean age = 62 years) and without (n = 25, mean age = 44 years) PVD (P PVD (2.98 ± 0.31 %W) compared to no PVD (1.97 ± 0.24 %W; P PVD than those without (P PVD status, vitreous echodensity, and age were the only independent variables demonstrating significant effects on CSF. Lens status, BCVA, and GCC thickness did not demonstrate association with CSF. PVD, vitreous echodensity, and age are determinants of CSF. PVD and increased vitreous echodensity are each associated with diminished CSF, independent of age. Thus, in the absence of GCC thinning and cataracts, vitreous changes may be a cause of decreased CSF with age.

  6. Vitreous floaters (Conference Presentation)

    Science.gov (United States)

    Kershaw, K.; Nguyen, Derek; Yee, Kenneth; Nguyen, Justin A.; Harrington, Michael G.; Sebag, Jerry

    2017-02-01

    BACKGROUND: Vitreous opacities and posterior vitreous detachment (PVD) disturb vision by degrading contrast sensitivity (AJO 172:7-12, 2016). Increased light scattering is the presumed mechanism. To test this hypothesis, dynamic light scattering (DLS) was performed on excised vitreous of patients with clinically significant floaters, and compared to macular pucker controls. METHODS: Undiluted, unfixed vitreous was procured during 25-gauge vitrectomy in 14 subjects (age = 59 +/- 6.6 years) with clinically significant vitreous floaters, and 6 controls (age = 66.5 +/- 8.7 years; P = 0.10) with macular pucker. Total protein concentration was determined by fluorescent Quant-iTTM protein assay kit (Invitrogen/Molecular Probes, Eugene, OR) with bovine serum albumin (0500 ng/ml) as a standard. Fluorescence (excitation at 470 nm and emission at 570 nm) was measured using a Gemini XPS Dual-Scanning Microplate Spectrofluorometer and data analyzed using SoftMax Pro software (Molecular Devices, Sunnyvale, CA). DLS (NS300, Malvern Instruments, Westborough, MA) measurements were performed in each specimen after 10-fold dilution in phosphate buffered saline to optimize concentration in each specimen and determine the mean number of particles, the particle size distributions, and the average particle sizes. RESULTS: Total protein concentration in vitreous specimens trended higher in macular pucker controls (1037 +/- 1038 μg/mL) than eyes with vitreous floaters (353.7 +/- 141.1 μg/mL P = 0.08). When normalized to total protein concentration, the number of particles in vitreous from floater eyes was more than 2-fold greater than controls (P < 0.04). Particle size distributions were similarly two-fold greater in vitreous from floater subjects as compared to controls (P < 0.05). The average particle size in vitreous from floater eyes was 315.8 +/- 194.6 nm, compared to 147.7 +/- 129.3 nm in macular pucker controls (P = 0.039). CONCLUSIONS: Vitreous from eyes with clinically

  7. Bilateral persistent hyperplastic primary vitreous

    Directory of Open Access Journals (Sweden)

    Jain Tarun

    2009-01-01

    Full Text Available A case of bilateral persistent hyperplastic primary vitreous (PHPV in a 3-month-old male infant, who had bilateral leukokoria, is presented. The child was referred for imaging with a clinical suspicion of retinoblastoma. Gray-scale ultrasound evaluation revealed an echogenic band in the posterior segment of both globes, extending from the posterior surface of the lens capsule to the optic disc. Doppler examination revealed the presence of arterial flow in the band in both globes. Associated echogenic hemorrhage was also seen, which was confirmed by computed tomography. Most cases of PHPV are sporadic and unilateral, and bilateral PHPV is rare. The imaging features in this case suggest the diagnosis of bilateral PHPV and differentiate it from retinoblastoma. This entity, although infrequent, should be considered in the differential diagnosis while evaluating bilateral leukokoria.

  8. Uveitis-glaucoma-hyphema syndrome associated with recurrent vitreous hemorrhage.

    Science.gov (United States)

    Alfaro-Juárez, A; Vital-Berral, C; Sánchez-Vicente, J L; Alfaro-Juárez, A; Muñoz-Morales, A

    2015-08-01

    A 61-year-old pseudophakic male with recurrent blurred vision episodes associated with uveitis, hyphema, glaucoma and vitreous hemorrhage. Iris transillumination defects and apposition of the optic and iris were found. The patient was diagnosed with Uveitis-Glaucoma-Hyphema (UGH) Syndrome. Mechanical irritation of the iris is a consequence of intraocular lens malposition and causes UGH Syndrome. Occasionally it is associated with vitreous hemorrhage. Lens malposition is detected by optical coherence tomography and/or ultrasound biomicroscopy. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  9. Removal of intraocular foreign body in anterior chamber angle with prism contact lens and 23-gauge foreign body forceps.

    Science.gov (United States)

    Huang, Yan-Ming; Yan, Hua; Cai, Jin-Hong; Li, Hai-Bo

    2017-01-01

    To introduce a novel approach in removal of anterior chamber angle foreign body (ACFB) using a prism contact lens and 23-gauge foreign body forceps. Data of 42 eyes of 42 patients who had undergone removal of ACFB using a prism contact lens and 23-gauge foreign body forceps from January 2008 to October 2013 were collected and analyzed. Twenty eyes in group A received the conventional approach by using toothed forceps through corneal limbus incision, and 22 eyes in group B underwent the novel method through the opposite corneal limbus incision. The success rate of ACFB once removal was 75% (15/20) in group A, and 100% (22/22) in group B. The average operation time of group A was significantly longer compared with group B (34.9±9.88min vs 22.13±8.85min; P contact lens and 23-gauge foreign body forceps is a safer, more effective, and convenient technique compared with the conventional approach.

  10. Vitreous vascular endothelial growth factor concentrations in proliferative diabetic retinopathy versus proliferative vitreoretinopathy.

    Science.gov (United States)

    Citirik, Mehmet; Kabatas, Emrah Utku; Batman, Cosar; Akin, Kadir Okhan; Kabatas, Naciye

    2012-01-01

    To assess vitreous vascular endothelial growth factor (VEGF) concentrations in proliferative diabetic retinopathy (PDR) in comparison to proliferative vitreoretinopathy (PVR). Vitreous samples were collected from 69 eyes of 69 patients with traumatic lens dislocation (n = 10), grade B PVR with rhegmatogenous retinal detachment (n = 13), grade C PVR with rhegmatogenous retinal detachment (n = 14), PDR with vitreous hemorrhage (n = 18), and PDR with vitreous hemorrhage and tractional retinal detachment (n = 14). Vitreous fluid samples were obtained at vitrectomy, and the levels of VEGF were measured by enzyme-linked immunosorbent assay. The mean vitreous level of VEGF was 15.14 ± 5.22 pg/ml in eyes with grade B PVR, 99.15 ± 38.58 pg/ml in eyes with grade C PVR, 4,534.01 ± 1,193.28 pg/ml in eyes with vitreous hemorrhage secondary to PDR, 5,157.29 ± 969.44 pg/ml in eyes with vitreous hemorrhage and tractional retinal detachment secondary to PDR, and 16.19 ± 5.76 pg/ml in eyes of the control group with traumatic lens dislocation. Vitreous VEGF concentrations were significantly higher in the patients with grade C PVR, PDR with vitreous hemorrhage and PDR with vitreous hemorrhage and tractional retinal detachment in comparison to the control patients (p < 0.05). A significant alteration was not observed in patients with grade B PVR (p = 0.55). Vitreous VEGF concentrations are increased in PDR and grade C PVR. The high VEGF concentrations could suggest a possible effect of VEGF on advanced PVR. Copyright © 2011 S. Karger AG, Basel.

  11. Vitreous humour - routine or alternative material for analysis in forensic medicine.

    Science.gov (United States)

    Markowska, Joanna; Szopa, Monika; Zawadzki, Marcin; Piekoszewski, Wojciech

    2017-01-01

    Biological materials used in toxicological analyses in forensic medicine traditionally include blood, urine and vitreous humour. Forensic use of the vitreous body is mostly due to the need to assess the endogenous concentration of ethyl alcohol in the process of human body decomposition. The vitreous body is an underestimated biological material, even though its biochemical properties and anatomical location make it suitable for specific forensic toxicology tests as a reliable material for the preparation of forensic expert opinions. Based on the available literature the paper gathers information on the biochemical structure of the vitreous body, ways to secure the material after collection and its use in postmortem diagnostics. Specific applications of the vitreous humour for biochemical and toxicological tests are discussed, with a focus on its advantages and limitations in forensic medical assessment which are attributable to its biochemical properties, anatomical location and limited scientific studies on the distribution of xenobiotics in the vitreous body.

  12. Variations of posterior vitreous detachment

    OpenAIRE

    Kakehashi, A.; Kado, M.; Akiba, J.; Hirokawa, H.

    1997-01-01

    AIMS—To identify variations in posterior vitreous detachment (PVD) and establish a clinical classification system for PVD.
METHODS—400 consecutive eyes were examined using biomicroscopy and vitreous photography and classified the PVD variations—complete PVD with collapse, complete PVD without collapse, partial PVD with thickened posterior vitreous cortex (TPVC), or partial PVD without TPVC.
RESULTS—In each PVD type, the most frequently seen ocular pathologies were as follows: in complete PVD ...

  13. Scleral suspension pars-plana lensectomy for ectopia lentis followed by suture fixation of intraocular lens

    Directory of Open Access Journals (Sweden)

    Mitra Sandip

    2001-01-01

    Full Text Available Purpose: To describe a simple technique of scleral suspension-pars plana lensectomy (SS-PPL in acquired and congenital ectopia lentis and scleral fixation of intraocular lens (IOL. Materials and Methods: Twenty eyes of 16 patients (12 unilateral and 4 bilateral cases of "essential familial lens subluxation" aged 10-40 years (mean 25 years underwent SS-PPL with implantation of scleral fixated IOL. Indications for surgery were best-corrected visual acuity <6/18, bisection of pupil by the lens, and lens-induced glaucoma. Prerequisites for SS-PPL were, visibility of part of the lens in the pupillary area and soft lens. Results: Postoperative visual acuity ranged from 6/6 - 6/36. Lens tilt in 3 cases(15% and small decentration in 2 cases(10% were seen; however these did not seriously compromise the visual result. Scant vitreous bleeding on the first postoperative day was seen in 3 cases (15%. Conclusion: The advantages of the scleral suspension of subluxated lens prior to lensectomy include stabilization; it allows proper viewing of the lens, avoids injury to the iris and cliary body during lensectomy and reduces the possibility of dislocation of the lens.

  14. [The vitreous and the macula].

    Science.gov (United States)

    Kishi, Shoji

    2015-03-01

    The macula is a site where various vitreoretinal disorders occur. In 1983 we started to observe the retinal surface of postmortem eyes with a scanning electron microscope (SEM). We investigated the anatomy of the vitreous in postmortem eyes by slit lamp biomicroscopy. The novel anatomy of the premacular vitreous led us to conduct a clinical study of vitreomacular interface diseases. In 1997, time domain optical coherence tomography(OCT) became available which facilitated visualization of the vitreoretinal interface. Swept source OCT which was introduced in 2012 can depict liquefied lacunae in the vitreous. It enabled us to elucidate the mechanism of vitreoretinal diseases. I. SEM revealed the remnants of vitreous cortex at fovea with high incidence (44%), which suggests strong vitreoretinal attachment at the fovea and vitreous cortex origin of the epiretinal membrane. II. We studied the anatomy of the vitreous in postmortem eyes. The vitreous of bisected eye balls was stained by fluorescein and immersed in water and observed by slit-lamp biomicroscopy. We discovered a "posterior precortical vitreous pocket (PPVP)" in adult eyes without posterior vitreous detachment (PVD). III. We performed clinical study in various vitreoretinal diseases based on the novel vitreous anatomy and explained their mechanism. 1. In diabetic retinopathy, ring shaped fibrovascular tissue surrounding the macula is formed along the outer margin of the PPVP. Although PVD progresses outside the PPVP, its posterior wall remains attached to the retina, which causes macular traction or cystoid macular edema. 2. In eyes with idiopathic epimacular membrane (IEM), detached vitreous cortex had an oval defect corresponding to the IEM. Posterior wall of the PPVP that is premacular vitreous cortex appeared to be the framework of IEM. 3. During vitrectomy for macular hole, premacular round defect appears when PVD is created. The residual cortex on the macula is fibrous membrane with elasticity. The

  15. Classification of posterior vitreous detachment

    Science.gov (United States)

    Kakehashi, Akihiro; Takezawa, Mikiko; Akiba, Jun

    2014-01-01

    Diagnosing a posterior vitreous detachment (PVD) is important for predicting the prognosis and determining the indication for vitreoretinal surgery in many vitreoretinal diseases. This article presents both classifications of a PVD by slit-lamp biomicroscopy and of a shallow PVD by optical coherence tomography (OCT). By biomicroscopy, the vitreous condition is determined based on the presence or absence of a PVD. The PVD then is classified as either a complete posterior vitreous detachment (C-PVD) or a partial posterior vitreous detachment (P-PVD). A C-PVD is further divided into a C-PVD with collapse and a C-PVD without collapse, while a P-PVD is divided into a P-PVD with shrinkage of the posterior hyaloid membrane (P-PVD with shrinkage) and a P-PVD without shrinkage of the posterior hyaloid membrane (P-PVD without shrinkage). A P-PVD without shrinkage has a subtype characterized by vitreous gel attachment through the premacular hole in a posterior hyaloid membrane to the macula (P-PVD without shrinkage [M]). By OCT, a shallow PVD is classified as the absence of a shallow PVD or as a shallow PVD. A shallow PVD is then subclassified as a shallow PVD without shrinkage of the posterior vitreous cortex, a shallow PVD with shrinkage of the posterior vitreous cortex, and a peripheral shallow PVD. A shallow PVD without shrinkage of the posterior vitreous cortex has two subtypes: an age-related shallow PVD and a perifoveal PVD associated with a macular hole. PMID:24376338

  16. Small-Gauge Pars Plana Vitrectomy for the Management of Symptomatic Posterior Vitreous Detachment after Phacoemulsification and Multifocal Intraocular Lens Implantation: A Pilot Study from the Pan-American Collaborative Retina Study Group

    Science.gov (United States)

    Navarro, Rodrigo M.; Machado, Leonardo M.; Maia, Ossires; Wu, Lihteh; Farah, Michel E.; Magalhaes, Octaviano; Arevalo, J. Fernando; Maia, Mauricio

    2015-01-01

    Purpose. To determine the efficacy of 23-gauge pars plana vitrectomy (PPV) for symptomatic posterior vitreous detachment (PVD) on visual acuity (VA) and quality after multifocal intraocular lenses (IOLs). Methods. In this prospective case series, patients who developed symptomatic PVD and were not satisfied with visual quality due to floaters and halos after multifocal IOL implantation underwent PPV. Examinations included LogMAR uncorrected visual acuity (UCVA), intraocular pressure, biomicroscopy, and indirect ophthalmoscopy at baseline and 1, 7, 30, and 180 days postoperatively. Ultrasonography and aberrometry were performed. The Visual Functioning Questionnaire 25 (VFQ-25) was administered preoperatively and at 30 days postoperatively. Both the postoperative UCVA and questionnaire results were compared to preoperative findings using the Wilcoxon test. Results. Sixteen eyes of 8 patients were included. VA significantly improved from 0.17 to 0.09 postoperatively (P = 0.017). All patients reported improvement of halos, glare, and floaters. VFQ-25 scores significantly improved in general vision (P = 0.023), near activities (P = 0.043), distance activities (P = 0.041), mental health (P = 0.011), role difficulties (P = 0.042), and driving (P = 0.016). Conclusion. PPV may increase UCVA and quality of vision in patients with bilateral multifocal IOLs and symptomatic PVD. Larger studies are advised. PMID:26504590

  17. Differentiation of Induced Pluripotent Stem Cells to Lentoid Bodies Expressing a Lens Cell-Specific Fluorescent Reporter.

    Directory of Open Access Journals (Sweden)

    Taruna Anand

    Full Text Available Curative approaches for eye cataracts and other eye abnormalities, such as myopia and hyperopia currently suffer from a lack of appropriate models. Here, we present a new approach for in vitro growth of lentoid bodies from induced pluripotent stem (iPS cells as a tool for ophthalmological research. We generated a transgenic mouse line with lens-specific expression of a fluorescent reporter driven by the alphaA crystallin promoter. Fetal fibroblasts were isolated from transgenic fetuses, reprogrammed to iPS cells, and differentiated to lentoid bodies exploiting the specific fluorescence of the lens cell-specific reporter. The employment of cell type-specific reporters for establishing and optimizing differentiation in vitro seems to be an efficient and generally applicable approach for developing differentiation protocols for desired cell populations.

  18. IOL Implants: Lens Replacement and Cataract Surgery (Intraocular Lenses)

    Science.gov (United States)

    ... Oncology Oculoplastics/Orbit Refractive Management/Intervention Retina/Vitreous Uveitis Focus On Pediatric Ophthalmology ... Are Cataracts? Pediatric Cataracts Cataract Diagnosis and Treatment Cataract Surgery IOL Implants: Lens Replacement After Cataracts ...

  19. Mixing processes in the vitreous chamber induced by eye rotations

    Energy Technology Data Exchange (ETDEWEB)

    Stocchino, Alessandro [Department of Civil, Environmental and Architectural Engineering, University of Genoa (Italy); Repetto, Rodolfo [Department of Engineering of Structures, Water and Soil, University of L' Aquila (Italy); Siggers, Jennifer H [Department of Bioengineering, Imperial College London, London SW7 2AZ (United Kingdom)], E-mail: jorma@diam.unige.it

    2010-01-21

    In this paper, we study a model of flow in the vitreous humour in the posterior chamber of the human eye, induced by saccadic eye rotations. We concentrate on the effect of the shape of the chamber upon the mixing properties of the induced flows. We make particle image velocimetry measurements of the fluid velocity in a transparent plastic (Perspex) model of the posterior chamber during sinusoidal torsional oscillations about a vertical axis. We use a Newtonian fluid to model the vitreous humour, which is most realistic when either the vitreous humour is liquefied or has been replaced by purely viscous tamponade fluids. The model of the posterior chamber is a sphere with an indentation, representing the effect of the lens. In spite of the purely periodic forcing, a steady streaming flow is generated, which plays a fundamental role in the mixing processes in the domain. The streaming flow differs markedly from that in a perfect sphere, and its topological characteristics change substantially as the frequency of oscillation varies. We discuss the flow characteristics in detail and show that, for physiological parameter values, the Peclet number (based on a suitable measure of the steady streaming velocity) is large, suggesting that advection strongly dominates over diffusion for mass transport phenomena. We also compute particle trajectories based on the streaming velocity and use these to investigate the stirring properties of the flow.

  20. Mixing processes in the vitreous chamber induced by eye rotations

    International Nuclear Information System (INIS)

    Stocchino, Alessandro; Repetto, Rodolfo; Siggers, Jennifer H

    2010-01-01

    In this paper, we study a model of flow in the vitreous humour in the posterior chamber of the human eye, induced by saccadic eye rotations. We concentrate on the effect of the shape of the chamber upon the mixing properties of the induced flows. We make particle image velocimetry measurements of the fluid velocity in a transparent plastic (Perspex) model of the posterior chamber during sinusoidal torsional oscillations about a vertical axis. We use a Newtonian fluid to model the vitreous humour, which is most realistic when either the vitreous humour is liquefied or has been replaced by purely viscous tamponade fluids. The model of the posterior chamber is a sphere with an indentation, representing the effect of the lens. In spite of the purely periodic forcing, a steady streaming flow is generated, which plays a fundamental role in the mixing processes in the domain. The streaming flow differs markedly from that in a perfect sphere, and its topological characteristics change substantially as the frequency of oscillation varies. We discuss the flow characteristics in detail and show that, for physiological parameter values, the Peclet number (based on a suitable measure of the steady streaming velocity) is large, suggesting that advection strongly dominates over diffusion for mass transport phenomena. We also compute particle trajectories based on the streaming velocity and use these to investigate the stirring properties of the flow.

  1. Refractive shifts in four selected artificial vitreous substitutes based on Gullstrand-Emsley and Liou-Brennan schematic eyes.

    Science.gov (United States)

    Gao, Qianying; Chen, Xiang; Ge, Jian; Liu, Yongji; Jiang, Zhaoxin; Lin, Zhi; Liu, Yaqin

    2009-07-01

    To determine and compare the refractive shifts based on Gullstrand-Emsley and Liou-Brennan schematic eyes after filling them with four selected artificial vitreous substitutes: silicone oil, heavy silicone oil, hydrogels, and encapsuled balanced salt solution. The optical constants of artificial vitreous body-filled eyes were calculated based on Gullstrand-Emsley and Liou-Brennan schematic eyes with accommodation relaxed. The theoretical refractive shifts in these two models were compared in pars plana vitrectomy (PPV), PPV plus lensectomized and PPV plus intraocular lens (IOL) eyes after four artificial vitreous tamponades. The Gullstrand-Emsley schematic eye shows refractive shifts of +8.710, -4.544, +1.136, and -0.338 D in PPV eyes; +11.044, +20.332, +16.351, and +17.413 D in PPV plus lensectomized eyes; and the need for IOL powers of +22.195, +22.366, +22.292, and +22.312 D in PPV plus IOL eyes in silicone oil, heavy silicone oil, hydrogels, and encapsuled balanced salt solution tamponade eyes, respectively. Similarly, the Liou-Brennan schematic eye induced shifts of +6.260, -3.266, +0.817, and -0.272 D in PPV eyes; +13.181, +20.654, +17.451, and +18.305 D in PPV plus lensectomized eyes; and the need IOL powers of +13.522, +23.767, +19.389, and +20.558 D in PPV plus IOL eyes, respectively. The Gullstrand-Emsley schematic eye is a convenient and accurate model for predicting refractive shifts for hydrogels and encapsuled balanced salt solution substitutes in PPV eyes. The Liou-Brennan schematic eye is recommended for silicone oil and heavy silicone oil in PPV eyes and for all four substitutes in PPV plus lensectomized eyes and PPV plus IOL eyes. In addition, the encapsuled balanced salt solution changes the refraction little in either schematic eye.

  2. Classification of posterior vitreous detachment

    OpenAIRE

    Kakehashi, Akihiro; Takezawa, Mikiko; Akiba, Jun

    2013-01-01

    Akihiro Kakehashi,1 Mikiko Takezawa,1 Jun Akiba21Department of Ophthalmology, Jichi Medical University, Saitama Medical Center, Saitama, 2Kanjodori Eye Clinic, Asahikawa, JapanAbstract: Diagnosing a posterior vitreous detachment (PVD) is important for predicting the prognosis and determining the indication for vitreoretinal surgery in many vitreoretinal diseases. This article presents both classifications of a PVD by slit-lamp biomicroscopy and of a shallow PVD by optical coherence tomography...

  3. Posterior vitreous detachment and retinal detachment after cataract surgery.

    Science.gov (United States)

    Ripandelli, Guido; Coppé, Andrea Maria; Parisi, Vincenzo; Olzi, Diego; Scassa, Cecilia; Chiaravalloti, Adele; Stirpe, Mario

    2007-04-01

    To evaluate possible changes of vitreous status in emmetropic eyes after uneventful phacoemulsification surgery, and possible related complications such as the onset of retinal detachment (RD). Retrospective case series. Four hundred fifty-three emmetropic eyes from 453 patients (mean age, 62.03+/-5.57 years) subjected to uneventful phacoemulsification with intraocular lens implantation in the capsular bag were considered in the study. They had a refractive error within +/-0.5 diopters (mean, -0.21+/-0.08). Eyes with peripheral retinal lattice degeneration were included only if asymptomatic and only if the degeneration involved one retinal quadrant. After cataract surgery, the 453 eyes were evaluated preoperatively at days 1, 15, and 30 and months 3, 6, 12, 18, 24, 36, 48, and 60. The whole period of follow-up was 5 years. Evaluation of vitreous status by biomicroscopic examination, indirect binocular ophthalmoscopy, and B-scan ultrasonography. Postoperative onset of posterior vitreous detachment (PVD) and RD. After cataract surgery, a PVD occurred in 107 of 141 (75.88%) eyes without preoperative PVD or lattice degeneration. Posterior vitreous detachment occurred in 41 of 47 eyes (87.23%) with preoperative lattice degeneration and no PVD. Eyes with preoperative lattice degeneration and postoperative PVD showed a higher incidence of RD after cataract surgery (21.27%) than eyes without preoperative PVD or lattice degeneration (0.70%). In all patients with lattice degeneration, RD originated from horseshoe retinal tears on lattice areas located on the superior quadrants. No correlation was observed between the development of RD and age. Our results suggest that the onset of postoperative PVD should be considered an important risk factor for the development of RD after cataract surgery, particularly in eyes with lattice areas.

  4. Computed tomography in the evaluation of patients with persistent hyperplastic primary vitreous (PHPV)

    International Nuclear Information System (INIS)

    Mafee, M.F.; Goldberg, M.F.; Valvassori, G.E.; Capek, V.

    1982-01-01

    The computed tomographic (CT) findings in 5 patients with proven persistent hyperplastic primary vitreous (PHPV) are described. PHPV arises when the embryonic hyaloid vascular system fails to regress normally. Clinically, this condition usually manifests an unilateral or bilateral leukokoria and is one of the more important and frequent conditions mimicking retinoblastoma. The spectrum of CT findings include: (a) soft-tissue replacement (infiltration) of the vitreous body; (b) retrolental soft tissue along the Cloquet canal; (c) absence of abnormal calcification within the orbit; (d) microphthalmus; (e) retrohyaloid layered blood; and (f) hypervascularity in the vitreous humor

  5. Combined application of ultrasound and of radiodiagnostic methods in diagnosis of posterior dislocation of the lens

    International Nuclear Information System (INIS)

    Preisova, J.; Vlkova, E.; Svacinova, J.; Papouskova, D.

    1990-01-01

    A case study is presented of a patient with opaque media of the left eye for seclusion and occlusion of the pupil. The cause of the unilateral chronic uveitis was visualized using ultrasound in A mode. It was found that the calcified lens was dislocated into the vitreous body and fixed to the posterior wall of the eye. The finding was confirmed by a negative X-ray picture and positive CT finding of a small foreign body with high density. The dislocation of the lens occurred after a blow on the left eye during boxing 15 years before the patient sought medical assistance for pain in the practically blind eyeball. (author). 4 figs., 9 refs

  6. Vitreous in lattice degeneration of retina.

    Science.gov (United States)

    Foos, R Y; Simons, K B

    1984-05-01

    A localized pocket of missing vitreous invariably overlies lattice degeneration of the retina. Subjects with lattice also have a higher rate of rhegmatogenous retinal detachment, which is usually a complication of retinal tears. The latter are in turn a result of alterations in the central vitreous--that is, synchysis senilis leading to posterior vitreous detachment. In order to determine if there is either an association or a deleterious interaction between the local and central lesions of the vitreous in eyes with lattice, a comparison was made in autopsy eyes with and without lattice the degree of synchysis and rate of vitreous detachment. Results show no association between the local and central vitreous lesions, indicating that a higher rate of vitreous detachment is not the basis for the higher rate of retinal detachment in eyes with lattice. Also, there was no suggestion of deleterious interaction between the local and central vitreous lesions, either through vitreodonesis as a basis for precocious vitreous detachment, or through a greater degree of synchysis as a basis for interconnection of local and central lacunae (which could extend the localized retinal detachment in eyes with holes in lattice degeneration).

  7. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....

  8. Efficiency of radiation protection equipment in interventional radiology: a systematic Monte Carlo study of eye lens and whole body doses

    International Nuclear Information System (INIS)

    Koukorava, C; Farah, J; Clairand, I; Donadille, L; Struelens, L; Vanhavere, F; Dimitriou, P

    2014-01-01

    Monte Carlo calculations were used to investigate the efficiency of radiation protection equipment in reducing eye and whole body doses during fluoroscopically guided interventional procedures. Eye lens doses were determined considering different models of eyewear with various shapes, sizes and lead thickness. The origin of scattered radiation reaching the eyes was also assessed to explain the variation in the protection efficiency of the different eyewear models with exposure conditions. The work also investigates the variation of eye and whole body doses with ceiling-suspended shields of various shapes and positioning. For all simulations, a broad spectrum of configurations typical for most interventional procedures was considered. Calculations showed that ‘wrap around’ glasses are the most efficient eyewear models reducing, on average, the dose by 74% and 21% for the left and right eyes respectively. The air gap between the glasses and the eyes was found to be the primary source of scattered radiation reaching the eyes. The ceiling-suspended screens were more efficient when positioned close to the patient’s skin and to the x-ray field. With the use of such shields, the H p (10) values recorded at the collar, chest and waist level and the H p (3) values for both eyes were reduced on average by 47%, 37%, 20% and 56% respectively. Finally, simulations proved that beam quality and lead thickness have little influence on eye dose while beam projection, the position and head orientation of the operator as well as the distance between the image detector and the patient are key parameters affecting eye and whole body doses. (paper)

  9. EURADOS intercomparisons in external radiation dosimetry: similarities and differences among exercises for whole-body photon, whole-body neutron, extremity, eye-lens and passive area dosemeters

    International Nuclear Information System (INIS)

    Romero, Ana M.; Grimbergen, Tom; McWhan, Andrew; Stadtmann, Hannes; Fantuzzi, Elena; Clairand, Isabelle; Neumaier, Stefan; Dombrowski, Harald; Figel, Markus

    2016-01-01

    The European Radiation Dosimetry Group (EURADOS) has been organising dosimetry intercomparisons for many years in response to an identified requirement from individual monitoring services (IMS) for independent performance tests for dosimetry systems. The participation in intercomparisons gives IMS the opportunity to show compliance with their own quality management system, compare results with other participants and develop plans for improving their dosimetry systems. In response to growing demand, EURADOS has increased the number of intercomparisons for external radiation dosimetry. Most of these fit into the programme of self-financing intercomparisons for dosemeters routinely used by IMS. This programme is being coordinated by EURADOS working group 2 (WG2). Up to now, this programme has included four intercomparisons for whole-body dosemeters in photon fields, one for extremity dosemeters in photon and beta fields, and one for whole-body dosemeters in neutron fields. Other EURADOS working groups have organised additional intercomparisons including events in 2014 for eye-lens dosemeters and passive area dosemeters for environmental monitoring. In this paper, the organisation and achievements of these intercomparisons are compared in detail focusing on the similarities and differences in their execution. (authors)

  10. Persistent hyperplastic primary vitreous: congenital malformation of the eye.

    Science.gov (United States)

    Shastry, Barkur S

    2009-12-01

    Persistent hyperplastic primary vitreous (PHPV), also known as persistent fetal vasculature, is a rare congenital developmental malformation of the eye, caused by the failure of regression of the primary vitreous. It is divided into anterior and posterior types and is characterized by the presence of a vascular membrane located behind the lens. The condition can be of an isolated type or can occur with other ocular disorders. Most cases of PHPV are sporadic, but it can be inherited as an autosomal dominant or recessive trait. Inherited PHPV also occurs in several breeds of dogs and cats. In a limited number of cases, Norrie disease and FZD4 genes are found to be mutated in unilateral and bilateral PHPV. These genes when mutated also cause Norrie disease pseudoglioma and familial exudative vitreoretinopathy that share some of the clinical features with PHPV. Mice lacking arf and p53 tumour suppressor genes as well as Norrie disease pseudoglioma and LRP5 genes suggest that these genes are needed for hyaloid vascular regression. These experiments also indicate that abnormalities in normal apoptosis and defects in Wnt signalling pathway may be responsible for the pathogenesis of PHPV. Identification of other candidate genes in the future may provide a better understanding of the pathogenesis of the condition that may lead to a better therapeutic approach and better management.

  11. Effect of neutron irradiation on vitreous carbon

    International Nuclear Information System (INIS)

    Kurolenkin, E.I.; Virgil'ev, Yu.S.; Chugunova, T.K.

    1989-01-01

    The change in mass (m), volume (V), specific electric resistance (ρ), coefficient of linear thermal expansion (α), dynamic elasticity modulus (E), and limit of bending strength (σ) of vitreous carbon are studied upon neutron irradiation. Samples for study were two forms of vitreous carbon obtained by hardening thermally reactive polymers at 900-1,000 degree K. Phenol-formaldehyde (bakelite lacquer A, Bakelite A) and furfural-phenol-formaldehyde (FM-2) resin were used. They were irradiated in the experimental water - water VVR-M reactor between 360-1,030 degree K. The maximal neutron flux was 1.65·10 21 neut/cm 2 . Neutron irradiation of vitreous carbon led to its shrinkage and accompanied weakening. Shrinkage and weakening of vitreous carbon was decreased with an increase of treatment and irradiation temperatures

  12. Thanatochemistry: Study of vitreous humor potassium

    African Journals Online (AJOL)

    Nilesh Keshav Tumram

    2014-02-18

    Feb 18, 2014 ... particularly vitreous potassium has received most attention. It is known that ... respect to different age and sex at different death intervals. The details regarding the ... Analyser by the Ion selective method. The reagents used ...

  13. Developmental abnormalities of the vitreous in mouse fetuses caused by simultaneous irradiation of x-rays and ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Shirai, S; Yuguchi, S; Majima, A [Nagoya City Univ. (Japan). Faculty of Medicine

    1980-10-01

    Eye abnormalities in mouse fetuses caused by irradiation of X-rays alone, or simultaneous irradiation of X-rays and ultrasound on day 7 of gestation were histologically studied on day 18 of gestation. Developmental abnormalities of the vitreous were examined in the present experiment, and the following results were obtained. 1. Developmental abnormalities of the vitreous were observed in 23 fetuses, and unilateral cases were 15 of 23 fetuses. In 31 eyes with these abnormalities, much more abundant mesenchymal tissue of components of primary vitreous was found in the retrolental vitreous cavity than in the normal eyes. 2. The above 31 eyes were also accompanied by a variety of ocular abnormalities such as microphthalmia, faulty closure of the fetal fissure, aplasia and hypoplasia of the optic nerve, goniodysgenesis, and corneolenticular adhesion. Complications observed to be associated with developmental abnormalities of the vitreous were lens abnormalities, retinal traction and fold, fibrovascular anastomosis between mesenchymal tissues of the chamber angle and vitreous cavity, retinal rosette, and anomalies of the optic nerve head. 3. The histological findings of 17 eyes corresponded to anterior persistent hyperplastic primary vitreous (PHPV) encountered clinically, those of 3 eyes to posterior PHPV, those of 6 eyes to mixed type of both anterior and posterior types, and those of 5 eyes to PHPV of the optic nerve head. In 3 bilateral cases, the type was different for either eye. 4. From these results, it was considered that the pathogenesis of PHPV of Reese and congenital retinal fold of Mann consists of the maldevelopment of the components of the primary vitreous, and that the type of defect depends on the portion involved and the degree depends on the time at which the maldevelopment occurs.

  14. Trace Elements Iron, Copper and Zinc in Vitreous of Patients with Various Vitreoretinal Diseases

    Directory of Open Access Journals (Sweden)

    Sulochana Konerirajapuram

    2004-01-01

    Full Text Available Purpose: To measure the concentrations of iron, copper and zinc in human vitreous and to interpret their levels with various vitreoretinal diseases like proliferative diabetic retinopathy, retinal detachment, intraocular foreign body, Eales′ disease and macular hole. Methods: Undiluted vitreous fluid collected during pars plana vitrectomy was used to measure trace elements using an atomic absorption spectrophotometer. Results: The level of vitreous iron increased threefold in Eales′ disease (1.85 ± 0.36 pg/ml, 2.5-fold in proliferative diabetic retinopathy (1.534 ± 0.17 pg/ml and 2.3-fold in eyes with intraocular foreign body (1.341 ± 0.25 pg/ml when compared with macular hole (0.588 ± 0.16 pg/ml. This was statistically significant (P < 0.05. Zinc was found to be low in Eales′ disease (0.57 ± 0.22 pg/ml when compared with other groups, though the difference was not statistically significant. Conclusion: The increased level of iron with decreased zinc content in Eales′ disease confirms the earlier reported oxidative stress mechanism for the disease. In proliferative diabetic retinopathy and intraocular foreign body the level of iron increases. This is undesirable as iron can augment glycoxidation, which can lead to increased susceptibility to oxidative damage, in turn causing vitreous liquefaction, posterior vitreous detachment and ultimately retinal detachment and vision loss

  15. Midline sclerotomy approach for intraocular foreign body removal in phakic eyes using endoilluminator: A novel technique

    Science.gov (United States)

    Ravani, Raghav; Chawla, Rohan; Azad, Shorya Vardhan; Gupta, Yogita; Kumar, Vinod; Kumar, Atul

    2018-01-01

    Purpose: The objective of this study is to describe the removal of retained intraocular foreign body (RIOFB) by bimanual pars plana vitrectomy through midline sclerotomy in phakic patients. Technique: Four eyes with RIOFB and clear lens underwent microincision vitrectomy surgery. A chandelier illumination was placed through one of the existing ports. The foreign body (FB) was localized by direct visualization (intravitreal) or indentation (pars plana), stabilized using an intraocular magnet/FB forceps introduced through a midline sclerotomy and freed of vitreous from all sides using a vitrectomy cutter through the other port bimanually, reoriented along their long axis and extracted through the midline sclerotomy. Results: All four FBs were removed successfully without slippage or damage to the clear lens. Conclusion: Chandelier illumination-assisted removal of FB through midline sclerotomy helps in easier localization, stabilization and removal, avoiding lens touch even in anteriorly located FBs such as at pars plana. PMID:29676316

  16. Test of ring, eye lens and whole body dosemeters for the dose quantity Hp(3) to be used in interventional radiology

    Science.gov (United States)

    Szumska, A.; Budzanowski, M.; Kopeć, R.

    2017-11-01

    In its statement on tissue reactions approved on 21st April 2011, the International Commission on Radiological Protection (ICRP, 2012) reviewed its recommendation concerning the equivalent dose limit for the eye lens and reduced the dose limits for occupationally exposed persons to 20 mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. This limit was approved and written down in the new EURATOM (European Atomic Energy Community) directive 2013/59 and in the IAEA (International Atomic Energy Agency) BSS (Basic Safety Standard) of July 2014. For that reason, the necessity to monitor the eye lens may become more important than it was before. However, specially dedicated dosemeters for the dose quantity Hp(3) are using very rarely. Commonly use are only whole body personal dosemeters for the personal dose equivalent quantities Hp(10) worn on the trunk and ring dosemeters worn on finger to measure the quantity Hp(0.07). Therefore, in this work it was investigated whether dosemeters from routine use calibrated in terms of Hp(10) and Hp(0.07) and worn on thyroid collar and protective apron could deliver similar results like dedicated eye lens dosemeter worn close to the eyes. The results show that the best method if dedicated eye lens dosimeters is not used is to measure doses in terms of Hp(0.07) on the thyroid collar (Pearson product, r=0.85). Obtained results shows also importance of proper localization of eye lens dosimeter (close to the eye, from side of the X-ray source).

  17. Retrospective Study of Vitreous Tap Technique Using Needle Aspiration for Management of Shallow Anterior Chamber during Phacoemulsification

    Directory of Open Access Journals (Sweden)

    Ashraf Ahmed Nossair

    2017-01-01

    Full Text Available Purpose. To evaluate the technique of vitreous tap using needle aspiration for management of anterior chamber shallowness during phacoemulsification. Methods. A retrospective study included 26 eyes of 17 patients who underwent phacoemulsification in which vitreous tap was performed using a 27-gauge needle attached to a 5 ml syringe, inserted 3.5 mm from the limbus to aspirate 0.2 ml of liquefied vitreous if a cohesive (OVD failed to sufficiently deepen the anterior chamber. Results. Preoperative anterior chamber depth was 2.31 ± 0.26 mm, axial length was 21.7 ± 0.67 mm, lens thickness was 4.5 ± .19 mm, and cataract grade was 3.77 ± 1.4. Preoperative CDVA in LogMAR units was 0.98 ± 0.75. Coexisting angle closure glaucoma was present in 7 patients (26.92% preoperatively. Vitreous needle tap was successful in vitreous removal on the first attempt in 26 eyes (100%. Postoperative follow-up period was 22.88 ± 10.24 (4–39 months. The final postoperative CDVA in LogMAR units was 0.07 ± 0.1, while the final postoperative IOP was 16.54 ± 1.45 mmHg. No complications related to vitreous tap were noted. Conclusion. Vitreous needle tap is a simple, cost-effective, and safe technique for management of shallow anterior chamber in phacoemulsification.

  18. Developmental abnormalities of the vitreous in mouse fetuses caused by simultaneous irradiation of x-rays and ultrasound

    International Nuclear Information System (INIS)

    Shirai, Shoichiro; Yuguchi, Shuji; Majima, Akio

    1980-01-01

    Eye abnormalities in mouse fetuses caused by irradiation of X-rays alone, or simultaneous irradiation of X-rays and ultrasound on day 7 of gestation were histologically studied on day 18 of gestation. Developmental abnormalities of the vitreous were examined in the present experiment, and the following results were obtained. 1. Developmental abnormalities of the vitreous were observed in 23 fetused, and unilateral cases were 15 of 23 fetuses. In 31 eyes with these abnormalities, much more abundant mesenchymal tissue of components of primary vitreous was found in the retrolental vitreous cavity than in the normal eyes. 2. The above 31 eyes were also accompanied by a variety of ocular abnormalities such as microphthalmia, faulty closure of the fetal fissure, aplasia and hypoplasia of the optic nerve, goniodysgenesis, and corneolenticular adhesion. Complications observed to be associated with developmental abnormalities of the vitreous were lens abnormalities, retinal traction and fold, fibrovascular anastomosis between mesenchymal tissues of the chamber angle and vitrious cavity, retinal rosette, and anomalies of the optic nerve head. 3. The histological findings of 17 eyes corresponded to anterior persistent hyperplastic primary vitreous (PHPV) encountered clinically, those of 3 eyes to posterior PHPV, those of 6 eyes to mixed type of both anterior and posterior types, and those of 5 eyes to PHPV of the optic nerve head. In 3 bilateral cases, the type was different for either eye. 4. From these results, it was considered that the pathogenesis of PHPV of Reese and congenital retinal fold of Mann consists of the maldevelopment of the components of the primary vitreous, and that the type of defect is depends on the portion involved and the degree depends on the time at which the maldevelopment occurs. (author)

  19. Early Vitrectomy for Vitreous Hemorrhage Associated With Retinal Tears

    NARCIS (Netherlands)

    Tan, H. Stevie; Mura, Marco; Bijl, Heico M.

    2010-01-01

    PURPOSE: To evaluate outcome of early surgery in vitreous hemorrhage, presumably associated with retinal tears. DESIGN: Retrospective, noncomparative interventional case series. METHODS: We included 40 consecutive cases in 39 patients treated with early vitrectomy for vitreous hemorrhage. Main

  20. Factors associated with pentosidine accumulation in the human vitreous

    NARCIS (Netherlands)

    Van Deemter, Marielle; Bank, Ruud A.; Vehof, Jelle; Hooymans, Johanna M. M.; Los, Leonoor I.

    Purpose: To explore factors associated with pentosidine accumulation in the human vitreous. Methods: Vitreous samples were obtained during trans pars plana vitrectomy for macular hole or rhegmatogenous retinal detachment. Patient characteristics included age, gender, and diabetes mellitus. Ocular

  1. Design of an Injectable in Situ Gelation Biomaterials for Vitreous Substitute

    DEFF Research Database (Denmark)

    Annaka, Masahiko; Mortensen, Kell; Vigild, Martin E.

    2011-01-01

    To adapt the physical properties of living materials to their biological function, nature developed various types of polymers with outstanding physical behavior. One example is the vitreous body, which is important intraocular elements not only because of its optical and mechanical performances, ...

  2. Anterior capsular support for posterior chamber intraocular lenses following vitreous loss in endocapsular surgery

    Directory of Open Access Journals (Sweden)

    Jacob Pushpa

    1993-01-01

    Full Text Available We used anterior capsular support for posterior chamber intraocular lenses (PC IOLs in fourteen eyes with large posterior capsular ruptures. An endocapsular technique preserved the anterior capsule and facilitated implantation. With a median follow up of 8.5 months, all patients had a visual acuity of 6/9 or better. One lens was lost in the vitreous and one patient had a clinically significant cystoid macular edema. In the event of a posterior capsular rupture we suggest this technique as an alternative to anterior chamber or scleral-fixated lenses

  3. Proteomic interactions in the mouse vitreous-retina complex.

    Directory of Open Access Journals (Sweden)

    Jessica M Skeie

    Full Text Available Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina.Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software.We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor.Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

  4. Proteomic interactions in the mouse vitreous-retina complex.

    Science.gov (United States)

    Skeie, Jessica M; Mahajan, Vinit B

    2013-01-01

    Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina. Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software. We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor. Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

  5. Continuous Curvilinear Capsulorhexis Training and Non-Rhexis Related Vitreous Loss: The Specificity of Virtual Reality Simulator Surgical Training (An American Ophthalmological Society Thesis).

    Science.gov (United States)

    McCannel, Colin A

    2017-08-01

    To assess the specificity of simulation-based virtual reality ophthalmic cataract surgery training on the Eyesi ophthalmic virtual reality surgical simulator, and test the hypothesis that microsurgical motor learning is highly specific. Retrospective educational interventional case series. The rates of vitreous loss and retained lens material, and vitreous loss and retained lens material associated with an errant continuous curvilinear capsulorhexis (CCC) were assessed among 1037 consecutive cataract surgeries performed during four consecutive academic years at a teaching hospital. The data were grouped by Eyesi use and capsulorhexis intensive training curriculum (CITC) completion. The main intervention was the completion of the CITC on the Eyesi. In the Eyesi simulator experience-based stratification, the vitreous loss rate was similar in each group (chi square p=0.95) and was not preceded by an errant CCC in 86.2% for "CITC done at least once", 57.1% for "CITC not done, but some Eyesi use", and 48.9% for "none" training groups (p=4×10-5). Retained lens material overall and occurring among the errant CCC cases was similar among training groups (p=0.82 and p=0.71, respectively). Eyesi capsulorhexis training was not associated with lower vitreous loss rates overall. However, non-errant CCC associated vitreous loss was higher among those who underwent Eyesi capsulorhexis training. Training focused on the CCC portion of cataract surgery may not reduce vitreous loss unassociated with an errant CCC. It is likely that surgical training is highly specific to the task being trained. Residents may need to be trained for all surgical steps with adequate intensity to minimize overall complication rates.

  6. ECTOPIC LENS EXTRACTION IN CHILDREN

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2002-12-01

    Full Text Available Background. Ectopia lentis continues to be a therapeutic challenge for ophthalmologists. It can occur as an isolated condition, after ocular trauma, in association with other ocular disorders, as part of a systemic mesodermal disease or a complication of general metabolic disorders. Minimal subluxation of the lens may cause no visual symptoms, but in more advanced cases serious optical disturbances arise. The most important is amblyopia. Surgical treatment options include iris manipulation, lens discission, aspiration, intracapsular or extracapsular extraction, and pars plana lensectomy. The choice of surgical technique remains controversial, in part because of the historically poor visual results and high rate of perioperative complications, including vitreous loss and retinal detachment.Methods. We describe a surgical technique based on the use of the Cionni endocapsular tension ring, dry irrigation aspiration of lens material, centration of the capsular bag and foldable intraocular lens implantation into the bag. With mentioned surgical technique 8 patients were operated; 4 boys and 4 girls, together 11 eyes.Results. The final BCVA after follow up period improved in 9 eyes and it remained the same as before operation in one eye. Statistical comparison of preoperative and postoperative visual acuities showed significant improvement. On the other hand there was no correlation between preoperative and postoperative visual acuity.Conclusions. This surgical procedure is an alternative approach in solving this challenging cases of ectopia lentis with good postoperative visual rehabilitation.

  7. Recent Advances and History of Vitreous Surgery

    Directory of Open Access Journals (Sweden)

    Tatsuya Mimura

    2011-01-01

    Full Text Available There have been tremendous advances in the small-gauge pars plana vitrectomy (PPV systems. This review provides an overview of the recent advances and state of the art of vitreous surgery. The two most innovative advancements that have been developed in this area are the small-gauge cutter and the new illuminating systems. Compared to the traditional 20-gauge PPV, transconjunctival sutureless small-gauge PPV is a safe and effective strategy to treat a variety of vitreoretinal diseases. Chandelier illumination allows better visualisation of vitreous for bimanual surgery. The small-gauge PPV provides benefits in terms of less inflammation, less patient discomfort, and faster recovery of the visual acuity.

  8. A case report of intraocular lens luxation with the capsular bag after vitrectomy.

    Science.gov (United States)

    Kawai, Kenji; Bando, Masayasu; Suzuki, Takahiro; Hayakawa, Kenji

    2004-04-01

    We experienced a case of intraocular lens (IOL) luxation with the capsular bag after vitrectomy. The case was a 66-year-old female in whom an IOL was implanted one year after surgery for giant tear retinal detachment using silicone oil. Four years after the implantation surgery, the patient suffered subluxation of the IOL with the capsular bag. Examinations of the luxated IOL with the capsular bag using a stereoscopic microscope confirmed the presence of silicone oil droplets between the capsule and the IOL. Adhesion of vitreous body residues was observed in the capsule. Luxation of the IOL was thought to be connected with chronic inflammation resulting from the use of silicone oil and repeated vitrectomy. In addition to examining pathological findings of luxated IOL, it would also be important in the future to identify the pathology of the capsular bag.

  9. Lens subluxation after plasmin and SF6 injections in rabbit eyes.

    Directory of Open Access Journals (Sweden)

    Wei-Chi Wu

    Full Text Available To investigate the rate of lens subluxation following plasmin and/or SF6 injections in eyes, and whether a subsequent elevated level of vascular endothelial growth factor (VEGF and vitreous tap would aggravate subluxation.Four groups of rabbits were used. Group 1 received an intravitreal injection (IVI of plasmin and SF6 in the right eye; group 2 received an IVI of plasmin in the right eye; group 3 received an IVI of SF6 in the right eye; and group 4 received an IVI of balanced salt solution in the right eye. After treatment, IVIs of VEGF were given and vitreous tap was performed three times, followed by clinical observation of lens subluxation and scanning electronic microscope evaluation of the zonular fibers.After IVIs of plasmin and SF6, and VEGF and vitreous tap had been performed one to three times, lens subluxation was noted in 0%, 43%, 71%, 71%, and 86% of the eyes in group 1. After IVIs of plasmin, VEGF, and vitreous tap had been performed one to three times, lens subluxation was noted in 11%, 22%, 44%, 44%, and 67% of the eyes in group 2. The eyes in group 3 and 4 did not show signs of lens subluxation after VEGF IVIs and vitreous tap. Histology confirmed zonular fiber damage in the eyes treated with plasmin.The incidence of lens subluxation increased following plasmin injections in the eyes, and this was aggravated by the subsequent high VEGF level in the eyes and vitreous tapping. Zonular fibers were disrupted following plasmin treatment. These effects should be kept in mind when using plasmin enzymes in patients with vitreoretinal abnormalities.

  10. Convective transport resistance in the vitreous humor

    Science.gov (United States)

    Penkova, Anita; Sadhal, Satwindar; Ratanakijsuntorn, Komsan; Moats, Rex; Tang, Yang; Hughes, Patrick; Robinson, Michael; Lee, Susan

    2012-11-01

    It has been established by MRI visualization experiments that the convection of nanoparticles and large molecules with high rate of water flow in the vitreous humor will experience resistance, depending on the respective permeabilities of the injected solute. A set of experiments conducted with Gd-DTPA (Magnevist, Bayer AG, Leverkusen, Germany) and 30 nm gadolinium-based particles (Gado CELLTrackTM, Biopal, Worcester, MA) as MRI contrast agents showed that the degree of convective transport in this Darcy-type porous medium varies between the two solutes. These experiments consisted of injecting a mixture of the two (a 30 μl solution of 2% Magnevist and 1% nanoparticles) at the middle of the vitreous of an ex vivo whole bovine eye and subjecting the vitreous to water flow rate of 100 μl/min. The water (0.9% saline solution) was injected at the top of the eye, and was allowed to drain through small slits cut at the bottom of the eyeball. After 50 minutes of pumping, MRI images showed that the water flow carried the Gd-DTPA farther than the nanoparticles, even though the two solutes, being mixed, were subjected to the same convective flow conditions. We find that the convected solute lags the water flow, depending on the solute permeability. The usual convection term needs to be adjusted to allow for the filtration effect on the larger particles in the form (1- σ) u . ∇ c with important implications for the modeling of such systems.

  11. Biochemical Analysis of Synovial Fluid, Cerebrospinal Fluid and Vitreous Humor at Early Postmortem Intervals in Donkeys

    Directory of Open Access Journals (Sweden)

    Doha Yahia

    2014-01-01

    Full Text Available Biochemical analysis of body fluids after death is a helpful tool in veterinary forensic medicine. Synovial fluid, cerebrospinal fluid (CSF and vitreous humor are easily accessible and well preserved from contamination. Five donkeys (Equus africanus asinus aged 1 - 2 years old were subjected to the study. Samples (Synovial fluid, CSF and vitreous humor were collected before death (antimortem and then at 2, 4, 6, 8, 10 and 12 hours postmortem. Samples were analyzed for glucose, chloride, sodium, magnesium, potassium, enzymes and total protein. Synovial fluid analysis showed that glucose concentration started to decrease at 6 hours postmortem, while magnesium level increased with time. Other parameters were more stable. CSF analysis showed several changes related to time after death as the decrease in glucose and sodium levels, and the increased levels of potassium, magnesium, calcium and total protein. Vitreous analysis revealed a reduction in glucose level and increased potassium and magnesium concentrations. The present study concluded that biochemical analysis of synovial fluid, vitreous humor and CSF can help in determination of time since death in donkeys. This study recommend using CSF for determination of early post-mortem intervals.

  12. Vitreous veils and radial lattice in Marshall syndrome.

    Science.gov (United States)

    Brubaker, Jacob W; Mohney, Brian G; Pulido, Jose S; Babovic-Vuksanovic, Dusica

    2008-12-01

    To report the findings of membranous vitreous veils and radial lattice in a child with Marshall syndrome. Observational case report. Retrospective review of medical records and fundus photograph of a 6-year-old boy with Marshall syndrome. Vitreoretinal findings were significant for bilateral membranous vitreous veils and radial lattice degeneration. This case demonstrates the occurrence of vitreous veils and radial lattice degeneration in patients with Marshall syndrome.

  13. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

  14. Acquired Nonpigmented Vitreous Cyst Associated With Lattice Degeneration.

    Science.gov (United States)

    Lu, Jing; Mai, Guiying; Liu, Ruyuan; Luo, Yan; Lu, Lin

    2017-10-01

    A 63-year-old male presented with a round-shaped floater and visual obscuration in the right eye. Clinical evaluation showed a nonpigmented vitreous cyst connected to a lattice degeneration by a stalk. Immunostaining of the vitreous cyst obtained from vitrectomy showed its origin of retinal neuroepithelium. The cyst was formed by continuous vitreous traction, which might tear up the disrupted retina at the area of lattice degeneration. This report added the lattice degeneration to the list of causes for the acquired vitreous cyst. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:856-858.]. Copyright 2017, SLACK Incorporated.

  15. Diabetes-induced oxidative stress in the vitreous humor

    Directory of Open Access Journals (Sweden)

    Zsuzsanna Géhl

    2016-10-01

    Conclusion: The study demonstrates that diabetes-associated redox alterations also reach the vitreous with the most prominent changes being increased protein carbonylation and increased antioxidant levels.

  16. Lens stem cells may reside outside the lens capsule: an hypothesis

    Directory of Open Access Journals (Sweden)

    Meyer Rita A

    2007-06-01

    Full Text Available Abstract In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors. Historically, the lens has been viewed as a closed system, in which cells at the periphery of the lens epithelium differentiate into fiber cells. Theoretical considerations led us to question whether the intracapsular lens is indeed self-contained. Since stem cells generate tumors and the lens does not naturally develop tumors, we reasoned that lens stem cells may not be present within the capsule. We hypothesize that lens stem cells reside outside the lens capsule, in the nearby ciliary body. Our ideas challenge the existing lens biology paradigm. We begin our discussion with lens background information, in order to describe our lens stem cell hypothesis in the context of published data. Then we present the ciliary body as a possible source for lens stem cells, and conclude by comparing the ocular lens with the corneal epithelium.

  17. Late onset retinoblastoma presenting with vitreous haemorrhage

    DEFF Research Database (Denmark)

    Bagger, Mette; Prause, Jan Ulrik; Heegard, Steffen

    2012-01-01

    in the retina. A vascularized gelatinous mass was revealed after vitrectomy. Later the patient developed white cysts in the anterior chamber and histological findings were indicative of a retinoblastoma. The patient was enucleated and the diagnosis of retinoblastoma was confirmed. Intraocular surgery in young...... people with unknown retinoblastoma enhances the risk of metastasis development, orbital recurrence and death. Unexplained vitreous haemorrhage can obscure the view of a tumour but ultrasonic findings of a retinal mass calls for further imaging e.g. through MRI. The case illustrates the importance...

  18. Mechanical Models of the Dynamics of Vitreous Substitutes

    Directory of Open Access Journals (Sweden)

    Krystyna Isakova

    2014-01-01

    Full Text Available We discuss some aspects of the fluid dynamics of vitreous substitutes in the vitreous chamber, focussing on the flow induced by rotations of the eye bulb. We use simple, yet not trivial, theoretical models to highlight mechanical concepts that are relevant to understand the dynamics of vitreous substitutes and also to identify ideal properties for vitreous replacement fluids. We first recall results by previous authors, showing that the maximum shear stress on the retina grows with increasing viscosity of the fluid up to a saturation value. We then investigate how the wall shear stress changes if a thin layer of aqueous humour is present in the vitreous chamber, separating the retina from the vitreous replacement fluid. The theoretical predictions show that the existence of a thin layer of aqueous is sufficient to substantially decrease the shear stress on the retina. We finally discuss a theoretical model that predicts the stability conditions of the interface between the aqueous and a vitreous substitute. We discuss the implications of this model to understand the mechanisms leading to the formation of emulsion in the vitreous chamber, showing that instability of the interface is possible in a range of parameters relevant for the human eye.

  19. Hugoniot curve of vitreous silica and crystallisation under shock

    International Nuclear Information System (INIS)

    Viard, Jean

    1959-01-01

    The Hugoniot curve of vitreous silica shows a discontinuity of slope towards 135 kb, a sign of the passage, from the vitreous state to a crystalline structure in the shock wave. Reprint of a paper published in Comptes rendus des seances de l'Academie des Sciences, t. 249, p. 820-822, sitting of 10 August 1959 [fr

  20. 21 CFR 886.4150 - Vitreous aspiration and cutting instrument.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vitreous aspiration and cutting instrument. 886.4150 Section 886.4150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cutting instrument. (a) Identification. A vitreous aspiration and cutting instrument is an electrically...

  1. Persistent hyperplastic primary vitreous: imaging evaluation

    International Nuclear Information System (INIS)

    Jacob, Beatriz Mahmud; Teixeira, Kim-Ir-Sen Santos; Figueiredo, Sizenildo da Silva; Nobrega, Bruno Barcelos da

    2003-01-01

    Persistent hyperplastic primary vitreous (PHPV) is a congenital developmental anomaly of the eye that primarily affects premature infants. PHPV results from failure of regression of the embryogenic primary vitreous and hyaloid vasculature, and proliferation of connective tissue. Three types of PHPV may be found: anterior, posterior and a combination of anterior and posterior. The clinical findings include leukocoria (white pupillary reflex) and microphthalmic eye. This anomaly is usually unilateral and unassociated with other systemic findings. The differential diagnosis between PHPV and other ocular diseases may be difficult due to similar features such as leukocoria, detached retina, retinal folds and cataract. Other diseases with similar features include retinoblastoma, isolated congenital cataract, retinopathy of prematurity and pseudo gliomas or leukocorias. Direct visualization of the remnants of the fetal hyaloid vascular system offers the best evidence of PHPV. However, diagnosis using the ophthalmoscope is sometimes impossible because of opaque tissues. In this circumstance an indirect visualization by ultrasound, computed tomography or magnetic resonance imaging may be useful. These imaging methods provide valuable information for the differentiation from other diseases, particularly retinoblastoma. The authors present a review of the literature and an iconographic study of the imaging findings in patients with PHPV. (author)

  2. Mechanisms of anomalous compressibility of vitreous silica

    Science.gov (United States)

    Clark, Alisha N.; Lesher, Charles E.; Jacobsen, Steven D.; Sen, Sabyasachi

    2014-11-01

    The anomalous compressibility of vitreous silica has been known for nearly a century, but the mechanisms responsible for it remain poorly understood. Using GHz-ultrasonic interferometry, we measured longitudinal and transverse acoustic wave travel times at pressures up to 5 GPa in vitreous silica with fictive temperatures (Tf) ranging between 985 °C and 1500 °C. The maximum in ultrasonic wave travel times-corresponding to a minimum in acoustic velocities-shifts to higher pressure with increasing Tf for both acoustic waves, with complete reversibility below 5 GPa. These relationships reflect polyamorphism in the supercooled liquid, which results in a glassy state possessing different proportions of domains of high- and low-density amorphous phases (HDA and LDA, respectively). The relative proportion of HDA and LDA is set at Tf and remains fixed on compression below the permanent densification pressure. The bulk material exhibits compression behavior systematically dependent on synthesis conditions that arise from the presence of floppy modes in a mixture of HDA and LDA domains.

  3. Toxic effects of extracellular histones and their neutralization by vitreous in retinal detachment.

    Science.gov (United States)

    Kawano, Hiroki; Ito, Takashi; Yamada, Shingo; Hashiguchi, Teruto; Maruyama, Ikuro; Hisatomi, Toshio; Nakamura, Makoto; Sakamoto, Taiji

    2014-05-01

    Histones are DNA-binding proteins and are involved in chromatin remodeling and regulation of gene expression. Histones can be released after tissue injuries, and the extracellular histones cause cellular damage and organ dysfunction. Regardless of their clinical significance, the role and relevance of histones in ocular diseases are unknown. We studied the role of histones in eyes with retinal detachment (RD). Vitreous samples were collected during vitrectomy, and the concentration of histone H3 was measured by enzyme-linked immunosorbent assay. The location of the histones and related molecules was examined in a rat RD model. The release of histones and their effects on rat retinal progenitor cells R28 and ARPE-19 were evaluated in vitro. In addition, the protective role of the vitreous body against histones was tested. The intravitreal concentration of histones was higher in eyes with RD (mean, 30.9 ± 9.8 ng/ml) than in control eyes (below the limit of detection, Phistone H3 was observed on the outer side of the detached retina and was associated with photoreceptor death. Histone H3 was released from cultured R28 by oxidative stress. Histones at a concentration 10 μg/ml induced the production of interleukin-8 in ARPE-19 cells (2.5-fold increase, PHistones were toxic to cells at concentrations of ≥ 20 μg/ml. Vitreous body or hyaluronan decreased toxicity of histones by inhibiting diffusion of histones. These results indicate that histones are released from retinas with RD and may modulate the subretinal microenvironment by functioning as damage-associated molecular pattern molecules, thereby inducing proinflammatory cytokines or cell toxicity. In addition, the important role of the vitreous body and hyaluronan in protecting the retina from these toxic effects is suggested.

  4. Interpretation of postmortem vitreous concentrations of sodium and chloride.

    Science.gov (United States)

    Zilg, B; Alkass, K; Berg, S; Druid, H

    2016-06-01

    Vitreous fluid can be used to analyze sodium and chloride levels in deceased persons, but it remains unclear to what extent such results can be used to diagnose antemortem sodium or chloride imbalances. In this study we present vitreous sodium and chloride levels from more than 3000 cases. We show that vitreous sodium and chloride levels both decrease with approximately 2.2mmol/L per day after death. Since potassium is a well-established marker for postmortem interval (PMI) and easily can be analyzed along with sodium and chloride, we have correlated sodium and chloride levels with the potassium levels and present postmortem reference ranges relative the potassium levels. We found that virtually all cases outside the reference range show signs of antemortem hypo- or hypernatremia. Vitreous sodium or chloride levels can be the only means to diagnose cases of water or salt intoxication, beer potomania or dehydration. We further show that postmortem vitreous sodium and chloride strongly correlate and in practice can be used interchangeably if analysis of one of the ions fails. It has been suggested that vitreous sodium and chloride levels can be used to diagnose drowning or to distinguish saltwater from freshwater drowning. Our results show that in cases of freshwater drowning, vitreous sodium levels are decreased, but that this mainly is an effect of postmortem diffusion between the eye and surrounding water rather than due to the drowning process, since the decrease in sodium levels correlates with immersion time. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Systemic Treatments for Noninfectious Vitreous Inflammation

    Directory of Open Access Journals (Sweden)

    Angela Jiang

    2013-01-01

    Full Text Available Vitreous inflammation, or vitritis, may result from many causes, including both infectious and noninfectious, including rheumatologic and autoimmune processes. Vitritis is commonly vision threatening and has serious sequelae. Treatment is frequently challenging, but, today, there are multiple methods of systemic treatment for vitritis. These categories include corticosteroids, antimetabolites, alkylating agents, T-cell inhibitors/calcineurin inhibitors, and biologic agents. These treatment categories were reviewed last year, but, even over the course of just a year, many therapies have made progress, as we have learned more about their indications and efficacy. We discuss here discoveries made over the past year on both existing and new drugs, as well as reviewing mechanisms of action, clinical dosages, specific conditions that are treated, adverse effects, and usual course of treatment for each class of therapy.

  6. Vitreous membranes used in the biogas purification

    International Nuclear Information System (INIS)

    Ortega Viera, L.; Rodriguez Munoz, S.; Fernandez Santana, E.; Martines Ramirez, Y.; Crespo Artigas, A.; Viera Gallardo, Y.

    2016-01-01

    In the present work 10 vitreous membranes with different masses of zinc oxide (ZnO(s)) and particle diameters charcoal (DPC) are used in the purification of biogas. The porosity and tortuosity of the membranes is obtained, showing the variation with respect to the composition thereof. From these structural features specific flow of H 2 S(g) is obtained which is transferred using the Fick's diffusion equation in the membranes and its value increases with increasing mass of ZnO(s). By X-ray diffraction membrane made with 3.16 g of ZnO(s) forming zinc sulfide it is shown, so we can say that the removal of H 2 S(g) occurs by a process of absorption with chemical reaction in the membranes. (Author)

  7. Positron annihilation in vitreous silica glasses

    International Nuclear Information System (INIS)

    Uedono, Akira; Tanigawa, Shoichiro

    1993-01-01

    The annihilation characteristics of positrons in vitreous silica glasses (v-SiO 2 ) were studied by measurements of two-dimensional angular correlation of positron annihilation radiations and positron lifetime spectra. From the measurements, it was found that positrons and positronium (Ps) atoms mainly annihilate from trapped states by vacancy-type defects in v-SiO 2 . For v-SiO 2 specimens with cylindrical porous structures, annihilations of Ps with anisotropic momentum distributions were observed. This fact was attributed to the momentum uncertainty due to localization of Ps in a finite dimension of pores. This investigation showed possibilities for the detection of microstructures in v-SiO 2 by the positron annihilation technique. (author)

  8. "Vitreous loss: Incidence and complications in extracapsular Cataract extractions "

    Directory of Open Access Journals (Sweden)

    Nikeghbali A

    2000-09-01

    Full Text Available One of the dangerous complications of cataract extractions is vitreous loss. The purpose of this stuy is to evaluate the incidence of vitreous loss and its sepuale while teaching residents at Rasoul Akram Hospital in Iran. This study has been conducted on existing records of 730 eyes which were subjectd to extracapsular cataract extractions by 3rd and 4th year, right handed resident of Rasoul Akram hospital. The information was taken from the records of patients who had vitreous loss during cataract surgery and the following data was extracted. The presence of any systemic diseases, phase of operation where vitreous loss occurred, vision on the next day, one month and 3 months later, the cause of low vision and any post operative sequale of the eye were evaluated. Extracted data collected and the prevalence of vitreous loss and its sequale were indentified and presented. Forty-nine eyes (6.7% had vitreous loss, thirty-one of them were in the left eye (63.3% and eighteen of them were in the right eye (36.7%. Regarding the stage of operation in which vitrous loss had occurred: twenty –eight eyes while nucleous delivery (57.7% eighteen eyes during aspiration of cortical material (36.7% and in three cases during IOL implantation. Five eyes had pseudoexfoliaton syndrome, four patients were diabetic and three had high myopia. Post operational sequale of these 49 eyes were: thirty-five with transient corneal edema (71.4%. Nine with misshaped pupils (18.9%, four with high astigmatism (8.1%, tow with cystoid macular edema (4%, two with retinal detachment (4% and seven with cloudy vitreous. (14.3%. The incidence of vitreous loss is more than expected. More extensive research to evaluated the prognositc factors according to the eye (OD/OS and the stage of the operation the leads to vitreous loss and to decrease its incidence is still needed.

  9. Posterior vitreous detachment induced by nattokinase (subtilisin NAT): a novel enzyme for pharmacologic vitreolysis.

    Science.gov (United States)

    Takano, Akiomi; Hirata, Akira; Ogasawara, Kazuya; Sagara, Nina; Inomata, Yasuya; Kawaji, Takahiro; Tanihara, Hidenobu

    2006-05-01

    To investigate the effects of intravitreal injection of nattokinase (subtilisin NAT), a serine protease that is produced by Bacillus subtilis (natto), for induction of posterior vitreous detachment (PVD). Different doses of nattokinase (1, 0.1, or 0.01 fibrin-degradation units [FU]) or physiologic saline as a control were injected into the vitreous cavity of rabbit eyes. Scanning electron microscopy was used to observe the retinal surfaces of four rabbit eyes per concentration. Histologic alterations were assessed by light microscopy, using four eyes from each group. Electroretinography (ERG) was performed to observe retinal function, ranging from 1 hour to 1 week after the nattokinase (1 or 0.1 FU) or saline solution administration, using four eyes from each group at each time point. Also, findings in all rabbits were monitored by slit lamp examination and by indirect ophthalmoscopy with a 20-D lens. Scanning electron microscopy showed smooth retinal surfaces, indicating the occurrence of PVD at 30 minutes after intervention in all the experimental eyes injected with 0.1 or 1.0 FU nattokinase, but none of the control eyes. Light microscopy and ERG analysis showed no critical change even after the use of 0.1 FU nattokinase, an amount sufficient to induce PVD. However, toxicity in the forms of preretinal hemorrhage and ERG changes was noted with the higher dose (1 FU) of nattokinase. The results suggested that nattokinase is a useful enzyme for pharmacologic vitreolysis because of its efficacy in inducing PVD.

  10. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory of probabil...

  11. Time course of development of posterior vitreous detachments after phacoemulsification surgery.

    Science.gov (United States)

    Hikichi, Taiichi

    2012-10-01

    To determine when posterior vitreous detachments (PVDs) develop after phacoemulsification and aspiration combined with foldable intraocular lens implantation. Prospective, consecutive case series. A total of 575 eyes without a PVD preoperatively were studied prospectively and followed for 3 years after uneventful phacoemulsification surgery. All patients underwent a comprehensive ocular examination, including a dynamic vitreous examination using biomicroscopy with and without a preset lens and a preoperative retinal examination on the day of surgery; the day postoperatively; 1 week and 1, 3, 6, and 12 months postoperatively; and every 6 months for 3 years postoperatively. The patients were divided into groups and analyzed on the basis of age and refractive error or axial length. The cumulative incidence rates of eyes that developed PVD for 3 years postoperatively at each postoperative time point. The cumulative numbers and percentages of eyes that developed a PVD were 6 (1.0%), 18 (3.1%), 31 (5.4%), 45 (7.8%), 63 (11.0%), 88 (15.3%), 106 (18.4%), 133 (23.1%), and 172 (30.0%) within 1 week and 1, 3, 6, 12, 18, 24, 30, and 36 months, respectively. Eleven (6.4%) of the 172 eyes in which a PVD developed during the follow-up period had new retinal breaks with or without a retinal detachment. Eight (15.4%) of 52 eyes with lattice degeneration and 3 (2.5%) of 120 eyes without lattice degeneration had retinal breaks associated with a PVD; these percentages were significant (P = 0.003). Development of PVDs seems to accelerate after phacoemulsification and linearly accumulated for 3 years postoperatively. Approximately 6% of eyes with a PVD had retinal breaks and eyes with lattice degeneration had a 6.2-fold higher risk of developing retinal breaks associated with a PVD. Long-term follow-up is needed after phacoemulsification is performed. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  12. Reticulated Vitreous Carbon Electrodes for Gas Phase Pulsed Corona Reactors

    National Research Council Canada - National Science Library

    Locke, B

    1998-01-01

    A new design for gas phase pulsed corona reactors incorporating reticulated vitreous carbon electrodes is demonstrated to be effective for the removal of nitrogen oxides from synthetic air mixtures...

  13. Reticulated Vitreous Carbon Electrodes for Gas Phase Pulsed Corona Reactors

    National Research Council Canada - National Science Library

    LOCKE, B

    1999-01-01

    A new design for gas phase pulsed corona reactors incorporating reticulated vitreous carbon electrodes is demonstrated to be effective for the removal of nitrogen oxides from synthetic air mixtures...

  14. Scleral Buckling Versus Primary Vitrectomy in the Management of Retinal Detachment Associated with Mild Vitreous Hemorrhage

    Directory of Open Access Journals (Sweden)

    Tansu Erakgün

    2014-03-01

    Full Text Available Objectives: The aim of this study was to compare the surgical impact of scleral buckling (SB and pars plana vitrectomy (PPV on the anatomic results and visual recovery in cases of rhegmatogenous retinal detachment with mild vitreous hemorrhage. Materials and Methods: In this study, we included 78 eyes of 78 phakic patients who underwent primary surgery for rhegmatogenous retinal detachment complicated by mild vitreous hemorrhage (38 eyes by SB,40 eyes by PPV;all patients had been followed for longer than 6 months after surgery. The surgical outcome and the rate of complications were retrospectively compared. Mann-Whitney U-test and chi-square test were used for the statistical analysis. Results: The reattachment rate after the first surgery was 78.9% (30/38 in the SB group and 95% (38/40 in the PPV group. The difference between the groups was statistically significant (p=0.035. Unseen retinal breaks in 4 eyes, malpositioned buckle in 2 eyes and insufficient closure of the break in 2 eyes of SB cases, as well as reopening of the original break in 2 eyes of PPV cases were the causes of failure. Visual improvement in the PPV group was significantly better than in the SB group in the third and sixth postoperative months (p<0.001 and p=0.026, respectively. Peroperative and postoperative complications were as follows: in the SB group-subretinal hemorrhage (5.2%, PVR of grade B or worse (10.5%, macular pucker (7.8%, and postoperative cataract (13%; in the PPV groupiatrogenic breaks (10%, lens damage (5%, PVR of grade B or worse (5%,macular pucker (5%, and postoperative cataract (35%. Conclusion: Even though the high incidence of peroperative complications such as iatrogenic breaks or postoperative complications such as cataract formation was the major drawback, the results indicate that PPV performed to alleviate peripheral vitreoretinal tractions and clear vitreous hemorrhage offers better anatomic and functional results than SB in the management of

  15. Structural refinement of vitreous silica bilayers

    Science.gov (United States)

    Sadjadi, Mahdi; Wilson, Mark; Thorpe, M. F.

    The importance of glasses resides not only in their applications but in fundamental questions that they put forth. The continuous random network model can successfully describe the glass structure, but determining details, like ring statistics, has always been difficult using only diffraction data. But recent atomic images of 2D vitreous silica bilayers can offer valuable new insights which are hard to be observed directly in 3D silica models/experiments (for references see). However, the experimental results are prone to uncertainty in atomic positions, systematic errors, and being finite. We employ special boundary conditions developed for such networks to refine the experimental structures. We show the best structure can be found by using various potentials to maximize information gained from the experimental samples. We find a range of densities, the so-called flexibility window, in which tetrahedra are perfect. We compare results from simulations using harmonic potentials, MD with atomic polarizabilities included and DFT. We should thank David Drabold and Bishal Bhattarai for useful discussions. Support through NSF Grant # DMS 1564468 is gratefully acknowledged.

  16. Crystalline lens dislocation secondary to bacterial endogenous endophthalmitis.

    Science.gov (United States)

    Sangave, Amit; Komati, Rahul; Weinmann, Allison; Samuel, Linoj; Desai, Uday

    2017-09-01

    To present an unusual case of endogenous endophthalmitis secondary to Group A streptococcus (GAS) that resulted in dislocation of the crystalline lens. An immunocompetent 51-year-old man presented to the emergency room (ER) with upper respiratory infection (URI) symptoms and painful right eye. He was diagnosed with URI and viral conjunctivitis and discharged on oral azithromycin and polytrim eyedrops. He returned to the ER 30 h later with sepsis and findings consistent with endophthalmitis, including light perception only vision. Ophthalmology was consulted at this time and an emergent vitreous tap and injection was performed. Both blood and vitreous cultures grew an atypical non-hemolytic variant of GAS ( Streptococcus pyogenes ). The primary source of infection was presumed to be secondary to pharyngitis or cutaneous dissemination. Final vision in the affected eye was no light perception, likely from a combination of anterior segment scarring, posterior segment damage, and hypotony. Interestingly, head computed tomography (CT) at the initial ER presentation showed normal lens position, but repeat CT at re-presentation revealed posterior dislocation of the lens. Endophthalmitis secondary to GAS has been sparsely reported in the literature, and this case highlights a unique clinical presentation. We suspect that this atypical non-hemolytic strain may have evaded detection on initial pharyngeal cultures. Additionally, we hypothesize that GAS-mediated protease release resulted in breakdown of the zonular fibers and subsequent lens dislocation. Ophthalmologists should be aware of GAS and its devastating intraocular manifestations.

  17. Lens dislocation has a possible relationship with laser iridotomy

    Directory of Open Access Journals (Sweden)

    Mutoh T

    2012-12-01

    Full Text Available Tetsuya Mutoh,1,2 Kevin F Barrette,2 Yukihiro Matsumoto,1 Makoto Chikuda11Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya City, Saitama, Japan; 2Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USAAbstract: We report our recent experience of four eyes with spontaneous lens dislocation in four patients with no history of trauma or any systemic disease associated with zonular dialysis. Lens dislocation developed with 0.5 to 6 months following laser iridotomy. All patients were male and two eyes were complicated with acute primary angle closure glaucoma preoperatively. Case 1 showed bilateral lens dislocation, while cases 2 and 3 involved unilateral lens dislocation. Cases 2 and 3 showed lenses completely dislocated into the vitreous cavity. All cases needed lens removal and scleral fixation of intraocular lenses. Final visual acuity was 1.2 in all cases. We suspect that laser iridotomy may induce localized zonular dialysis that results in progressive zonular weakness, leading to lens dislocation.Keywords: lens dislocation, laser iridotomy, primary angle closure glaucoma

  18. Crystalline lens thickness determines the perceived chromatic difference in magnification.

    Science.gov (United States)

    Chen, Yun; Schaeffel, Frank

    2014-03-01

    Since the origin of the high interindividual variability of the chromatic difference in retinal image magnification (CDM) in the human eye is not well understood, optical parameters that might determine its magnitude were studied in 21 healthy subjects with ages ranging from 21 to 58 years. Two psychophysical procedures were used to quantify CDM. They produced highly correlated results. First, a red and a blue square, presented on a black screen, had to be matched in size by the subjects with their right eyes. Second, a filled red and blue square, flickering on top of each other at 2 Hz, had to be adjusted in perceived brightness and then in size to minimize the impression of flicker. CDM varied widely among subjects from 0.0% to 3.6%. Biometric ocular parameters were measured with low coherence interferometry and crystalline lens tilt and decentration with a custom-built Purkinjemeter. Correlations were studied between CDM and corneal power, anterior chamber depth, lens thickness, lens tilt and lens decentration, and vitreous chamber depths. Lens thickness was found significantly correlated with CDM and accounted for 64% of its variance. Vertical lens tilt and decentration were also significantly correlated. It was also found that CDM increased by 3.5% per year, and part of this change can be attributed to the age-related increase in lens thickness.

  19. Comparison of lens oxidative damage induced by vitrectomy and/or hyperoxia in rabbits

    Directory of Open Access Journals (Sweden)

    Hong Yan

    2017-02-01

    Full Text Available AIM: To compare of lens oxidative damage induced by vitrectomy and/or hyperoxia in rabbit. METHODS: Sixteen New Zealand rabbits (2.4-2.5 kg were randomly divided into two groups (Group A, n=12; Group B, n=4. In Group A, the right eyes were treated with vitrectomy and systemic hyperoxia (oxygen concentration: 80%-85%, 1 ATA, 4h/d (Group A-right, and the left eyes were treated with hyperoxia without vitrectomy surgery (Group A-left. Four rabbits in group B (eight eyes were untreated as the controls. Lens transparency was monitored with a slit lamp and recorded before and after vitrectomy. After hyperoxic treatment for 6mo, the eyeballs were removed and the lens cortices (containing the capsules and nuclei were separated for further morphological and biochemical evaluation. RESULTS: Six months after treatments, there were no significant morphological changes in the lenses in any experimental group when observed with a slit lamp. However, the levels of water-soluble proteins and ascorbate, and the activities of catalase and Na+-K+-ATPase were significantly reduced, whereas the levels of malondialdehyde and transforming growth factor β2 (TGF-β2 were significantly elevated, in both the cortices and nuclei of eyes treated with vitrectomy and hyperoxia. The increase in protein-glutathione mixed disulfides and the reduction in water-soluble proteins were more obvious in the lens nuclei. The levels of ascorbate in the vitreous fluid were also reduced after vitrectomy, whereas TGF-β2 increased after vitrectomy and hyperoxia. Systemic hyperoxia exposure increased these effects. CONCLUSION: Removal of the intact vitreous gel with vitrectomy and exposing the lens to increased oxygen from the retina induce lens oxidation and aggregation. Thus, an intact vitreous gel structure may protect the lens from oxidative insult and maintain lens transparency.

  20. Clinical research on the development of posterior vitreous detachments after coaxial microincision phacoemulsification

    Directory of Open Access Journals (Sweden)

    Rong Xu

    2013-09-01

    Full Text Available AIM: To explore the development process of when posterior vitreous detachments(PVDsafter coaxial micro-incision phacoemulsification and aspiration combined with foldable intraocular lens implantation.METHODS: Clinical data of 917 patients with cataract were collected after coaxial microincision phacoemulsification and aspiration combined with foldable intraocular lens implantation. The 917 operating eyes forms observation group and the 917 corresponding normal eyes serve as control group. All patients underwent a comprehensive ocular examination before surgery. The vitreous and retinal condition was tested by B-scan ultrasonography and biomicroscope with a 90-diopter(Dpreset lens after 1 week and 1, 3, 6, and 12 months postoperatively. RESULTS: The incident rate of eyes in the observation group that developed PVD after operation were 8(0.9%, 31(3.4%, 53(5.8%, 78(8.5%, 129(14.1%within 1 week and 1, 3, 6, 12 months, respectively. Ten(7.8%of the 129 eyes in which PVD developed during the one year follow-up period had new retinal breaks with or without a retinal detachment; One(0.1%of the 788 eyes in which a PVD did not developed during the follow-up period had new retinal tear with or without a retinal detachment; these percentages were statistically significant(P=0.009. Eight(14.8%of 54 eyes with lattice degeneration and 2(2.7%of 75 eyes without lattice degeneration had retinal tears associated with a PVD; the difference was statistically significant(P=0.004.CONCLUSION: Development of PVDs seems to accelerate after coaxial microincision phacoemulsification and linearly accumulated for 1 year postoperatively. Approximately 7.8% of eyes with a PVD had retinal tears. Compared with patients having no lattice degeneration, Patients' eyes with lattice degeneration had a 5.5-fold higher risk of developing retinal breaks associated with a PVD. This indicates long-term follow-up is necessary after phacoemulsification is performed.

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Intervention Retina/Vitreous Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy ...

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Ophthalmology/Strabismus Ocular Pathology/Oncology Oculoplastics/Orbit Refractive Management/Intervention Retina/Vitreous Uveitis Focus ... Eye Health A-Z Symptoms Glasses & Contacts Tips & ...

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Ophthalmology/Strabismus Ocular Pathology/Oncology Oculoplastics/Orbit Refractive Management/Intervention Retina/Vitreous Uveitis Focus ... Halloween Hazard: The Hidden Dangers of Buying Decorative Contact Lenses Without ...

  4. The vitreous state thermodynamics, structure, rheology, and crystallization

    CERN Document Server

    Gutzow, Ivan S

    2013-01-01

    This book summarizes the experimental evidence and modern classical and theoretical approaches in understanding the vitreous state, from structural problems, over equilibrium and non-equilibrium thermodynamics, to statistical physics. Glasses, and especially silicate glasses, are only the best known representatives of this particular physical state of matter. Other typical representatives include organic polymer glasses, and many other easily vitrifying organic and inorganic substances, technically important materials, amidst them vitreous water and vitrified aqueous solutions, and also many metallic alloy systems. Some of these systems only form glasses under particular conditions, e.g. through ultra-rapid cooling. This book describes the properties and the formation of both every-day technical glasses and especially of such more exotic forms of vitreous matter. It is a unique source of knowledge and new ideas for materials scientists, engineers and researchers working on condensed matter. The new edition e...

  5. Functional characteristics of vitreous membranes used in biogas purification

    International Nuclear Information System (INIS)

    Ortega Viera, Lianys; Ponce Abreu, Kizzy Diarelys; Fernández Santana, Elina; Muñoz, Susana Rodríguez; Bárcenas Pérez, Liuver

    2016-01-01

    The removal of hydrogen sulfide (H_2S(g)) present in the biogas using vitreous membranes, is a method that has satisfactory results at a laboratory scale. To this end 10 membranes with different masses of zinc oxide (ZnO(s)) and particle diameters coal (Dpc) are applied. Therefore, the objective of this work is to perform the functional characterization of vitreous membranes used in the purification of biogas. The results indicate that the permeability and effective diffusivity of H_2S(g) in the vitreous membranes vary with respect to its composition and structural features. In addition, by Pareto diagram it can be shown that the mass of ZnO(s) as well as the Dpc and the operation flow (Qop) significantly influence the removal of H_2S(g). (author)

  6. Vitreous humor and albumin augment the proliferation of cultured retinal precursor cells

    DEFF Research Database (Denmark)

    Yang, Jing; Klassen, Henry; Pries, Mette

    2008-01-01

    concentrations of vitreous fluid supplementation was quantified by using a (3)H-thymidine incorporation assay. Active components of vitreous fluid were partially characterized by gel filtration chromatography (GFC) and UV spectral analysis. The effect of each vitreous fraction on proliferation was determined...... Da, consistent with ascorbic acid. Ascorbic acid was confirmed in vitreous fluid by UV spectral analysis. Growth-augmenting activity was present in higher molecular mass vitreous fractions, consistent with protein components. Albumin, the major protein in vitreous fluid, was found to augment...... proliferation. Because vitreous-associated augmentation of retinal precursor proliferation remains an epidermal growth factor-dependent phenomenon, the proliferative status of transplanted cells in the vitreous cavity is likely determined by a combination of factors. (c) 2008 Wiley-Liss, Inc....

  7. Vitreous-enamel protective coatings for niobium and niobium alloys

    International Nuclear Information System (INIS)

    Kobyakov, V.P.; Sedmale, G.P.; Tsimdin', R.A.; Sedmalis, U.Ya.; Tsetskhladze, D.L.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Sukhumi. Fiziko-Tekhnicheskij Inst.)

    1988-01-01

    Vitreous-enanel coatings to protect niobium and niobium alloys, used in oxidizing media at temperatures up to 1000degC, from embrittlement are developed on the basis of Al 2 O 3 -SiO 2 -P 2 O 5 -Ba vetrificating system. By means of microhardness measurement and IR-spectroscopy it is found, that at coating formation the intermediate ∼20 mkm width zone which prevents oxygen penetration in niobium is formed. Test of niobium pieces with ERS-1000 vitreous-enamel coating have shown, that coating provides niobium reliable protection in the air at 800degC and atmospheric pressure

  8. Vitreous loss-causes, associations, and outcomes: Eight-year analysis in Melaka Hospital

    Directory of Open Access Journals (Sweden)

    Thanigasalam Thevi

    2018-01-01

    CONCLUSION: Vitreous loss occurred in almost all types of cataract surgeries, especially by junior surgeons, among those aged <40 years and significantly caused poor visual outcome compared to other complications. Pseudoexfoliation had higher occurrence of vitreous loss. Vitreous loss patients had impaired/poor visual outcome due to preexisting comorbidity and astigmatism. Patients at risk and junior surgeons should be closely monitored to improve outcomes. Further studies need to be done to see why and when the vitreous loss occurred.

  9. Survey: technique of performing intravitreal injection among members of the Brazilian Retina and Vitreous Society (SBRV

    Directory of Open Access Journals (Sweden)

    Helio F. Shiroma

    2015-02-01

    Full Text Available Purpose: To evaluate and describe the precautions involved in the technique of intravitreal injection of antiangiogenic drugs adopted by the ophthalmologists who are members of the Brazilian Society of Retina and Vitreous (SBRV. Methods: A questionnaire containing 22 questions related to precautions taken before, during, and after intravitreal injection was sent electronically to 920 members of SBRV between November 15, 2013 and April 31, 2014. Results: 352 responses (38% were obtained. There was a predominance of men (76% from the southwest region of Brazil (51%. The professional experience varied between 6 and 15 years after medical specialization (50%. Most professionals (76% performed an average of 1 to 10 intravitreal injections a week, and 88% of the procedures were performed in the operating room using povidone iodine (99%, sterile gloves, and blepharostat (94%. For inducing topical anesthesia, usage of anesthetic eye drops was the most used technique (65%. Ranibizumab (Lucentis® was the most common drug (55%, and age-related macular degeneration (AMD was the most treated disease (57%. Regarding the complications treated, 6% of the ophthalmologists had treated at least one case of retinal detachment, 20% had treated cases of endophthalmitis, 9% had treated cases of vitreous hemorrhage, and 12% had encountered cases of crystalline lens touch. Conclusion: Intravitreal injection is a procedure routinely performed by retina specialists and has a low incidence of complications. Performing the procedure in the operating room using an aseptic technique was preferred by most of the respondents. Ranibizumab was the most used drug, and AMD was the most treated disease.

  10. Role of avastin on the incidence of post-operative vitreous hemorrhage after vitrectomy in diabetic vitreous hemorrhage

    International Nuclear Information System (INIS)

    Ahmed, N.; Shaheer, M.; Tahir, M.Y.

    2014-01-01

    Diabetic retinopathy is one of the most common cause of legal blindness. Five to 10% of diabetic patients suffer from the proliferative diabetic retinopathy which includes the formation of new vessels on the retina and optic disc which can be complicated as vitreous hemorrhage and tractional retinal detachment. Pars plana vitrectomy along with laser photocoagulation is being used for the management of vitreous hemorrhage. In our study we used injection avastin one week before surgery to see its role on the incidence of rebleed after vitrectomy in diabetic vitreous hemorrhage. Materials and Methods; Fifty patients were divided into 2 equal groups on the basis of simple random sampling. 25 patients in Group I were operated with routine pars plana vitrectomy with endolaser photo- coagulation while in Group II all the 25 patients were given injection avastin intra-vitreally one week before surgery. Evaluation was done on the first post operative day, first follow up visit (one week) and after one month to see the incidence of re-bleed. Chi-square test was used for statistical analysis. Results: Fifty patients divided into two groups. In Group I, 3 patients had recurrent vitreous hemorrhage on first post-operative day, 3 patients had re-bleed on first follow up visit, and only 2 patients had re-bleed after one month. In Group II, none of the patients had recurrent vitreous hemorrhage on first post-operative day and on first follow-up visit (one week) while 2 patients had re-bleed after one month. Conclusion: Injection intravitreal Avastin (Bevaci- zumab) one week before surgery significantly reduces the risk of vitreous hemorrhage after vitrectomy in diabetic patients. (author)

  11. A metabolomic approach to animal vitreous humor topographical composition: a pilot study.

    Directory of Open Access Journals (Sweden)

    Emanuela Locci

    Full Text Available The purpose of this study was to evaluate the feasibility of a (1H-NMR-based metabolomic approach to explore the metabolomic signature of different topographical areas of vitreous humor (VH in an animal model. Five ocular globes were enucleated from five goats and immediately frozen at -80 °C. Once frozen, three of them were sectioned, and four samples corresponding to four different VH areas were collected: the cortical, core, and basal, which was further divided into a superior and an inferior fraction. An additional two samples were collected that were representative of the whole vitreous body. (1H-NMR spectra were acquired for twenty-three goat vitreous samples with the aim of characterizing the metabolomic signature of this biofluid and identifying whether any site-specific patterns were present. Multivariate statistical analysis (MVA of the spectral data were carried out, including Principal Component Analysis (PCA, Hierarchical Cluster Analysis (HCA, and Partial Least Squares Discriminant Analysis (PLS-DA. A unique metabolomic signature belonging to each area was observed. The cortical area was characterized by lactate, glutamine, choline, and its derivatives, N-acetyl groups, creatine, and glycerol; the core area was characterized by glucose, acetate, and scyllo-inositol; and the basal area was characterized by branched-chain amino acids (BCAA, betaine, alanine, ascorbate, lysine, and myo-inositol. We propose a speculative approach on the topographic role of these molecules that are mainly responsible for metabolic differences among the as-identified areas. (1H-NMR-based metabolomic analysis has shown to be an important tool for investigating the VH. In particular, this approach was able to assess in the samples here analyzed the presence of different functional areas on the basis of a different metabolite distribution.

  12. Converging or Diverging Lens?

    Science.gov (United States)

    Branca, Mario

    2013-01-01

    Why does a lens magnify? Why does it shrink objects? Why does this happen? The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A converging lens can also act as a diverging lens. (Contains 4 figures.)

  13. Optical constants of quartz, vitreous silica and neutron-irradiated vitreous silica. II. Analysis of the infrared spectrum of vitreous silica

    Energy Technology Data Exchange (ETDEWEB)

    Gaskell, P H [Cambridge Univ. (UK). Cavendish Lab.; Johnson, D W [Pilkington Research and Development Laboratories, Lathom, nr. Ormskirk, Lancashire, UK

    1976-03-01

    Optical constant data for vitreous silica and neutron-irradiated vitreous silica, given in part I are examined in an attempt to gain further knowledge of the structure of the glass. Strong features of the spectrum can be described by band broadening parameters, which are calculated using an extension of the Wilson GF matrix method, and are shown to be quantitatively related to the distribution of Si-O distances and oxygen bond angles obtained from X-ray scattering data. The approximation commonly used to generate the optically active vibrational spectra of glasses, namely to form the product of the vibrational density of states function and a weakly frequency-dependent intensity factor gives a relatively poor representation of the experimental spectrum. The magnitude of 'disorder-induced' absorption in regions well away from the major bands is semi-quantitatively estimated by subtracting the contributions of the major bands. Interpretation of some of the features of this difference spectrum is possible in terms of vibrations of nonbridging oxygen atoms, but if this interpretation is correct, it is necessary to postulate clustering of 'dangling' oxygen atoms, which would not be consistent with a random network model for the structure. An alternative explanation, that the vibrations are framework modes, leads to the conclusion that the preferred configuration in vitreous silica resembles the arrangement of silicon-oxygen tetrahedra in cristobalite.

  14. Persistent hyperplastic primary vitreous – The martini glass sign

    African Journals Online (AJOL)

    2014-06-20

    /radiographics.14.5.7991814. 2. Küker W, Ramaekers V. Persistent hyperplastic primary vitreous: MRI. Neuroradiology. 1999;41(7):520–522. PMID: 10450848. http:// · dx.doi.org/10.1007/s002340050796. 3. Sun MH, Kao LY, ...

  15. Recurrent Vitreous Hemorrhage from an Optic Nerve Retinal Arterial Macroaneurysm

    Directory of Open Access Journals (Sweden)

    Jessica F. Yang

    2017-10-01

    Full Text Available Objective: To report a case of recurrent vitreous hemorrhage from an optic nerve retinal arterial macroaneurysm (ONRAM successfully treated with intraoperative endolaser. Patient and Methods: A 92-year-old woman on oral aspirin and warfarin anticoagulation for atrial fibrillation developed three episodes of dense vitreous hemorrhage from an ONRAM. Due to failure of the vitreous hemorrhage to clear spontaneously, a total of three pars plana vitrectomy (PPV procedures were performed along with a 1.25-mg intravitreal bevacizumab injection after the third episode of hemorrhage. During the third PPV procedure, a 25-gauge 532-nm green diode laser endoprobe was used to deliver low-power (100 mW and long-duration (500 ms laser spots directly on the ONRAM to induce intraoperative shrinkage of the ONRAM. Results: After the endolaser treatment, the macroaneurysm showed involution due to fibrosis without any adverse effects on retinal circulation or visual field defect. No recurrence of vitreous hemorrhage was noted after 2 years of follow-up. Conclusion: Oral anticoagulant use may have been responsible for the atypical clinical course in our patient. Laser photocoagulation, including intraoperative endolaser photocoagulation, may be considered in selected cases of symptomatic ONRAMs.

  16. NOVEL PRERETINAL HAIR PIN-LIKE VESSEL IN RETINAL ASTROCYTIC HAMARTOMA WITH VITREOUS HEMORRHAGE.

    Science.gov (United States)

    Soeta, Megumi; Arai, Yusuke; Takahashi, Hidenori; Fujino, Yujiro; Tanabe, Tatsuro; Inoue, Yuji; Kawashima, Hidetoshi

    2018-01-01

    To report a case of retinal astrocytic hamartoma with vitreous hemorrhage and a hair pin-like vessel adhering to a posterior vitreous membrane. A 33-year-old man with a retinal astrocytic hamartoma presented with vitreous hemorrhage 5 times. Multimodal imaging, including fundus photography, fluorescein angiography, optical coherence tomography, and B-mode ultrasonography. Multimodal imaging demonstrated a novel hair pin-like vessel that adhered to the posterior vitreous membrane. Some cases of retinal astrocytic hamartoma with vitreous hemorrhage may be related to structure abnormalities of tumor vessels.

  17. Treatment of a dislocated lens by transcorneal vitrectomy and bimanual phacoemulsification

    Directory of Open Access Journals (Sweden)

    Watanabe A

    2014-08-01

    Full Text Available Akira Watanabe, Tamaki Gekka, Hiroshi Tsuneoka Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan Background: As a method of treatment for a dropped lens nucleus, which occurred during cataract surgery, the dropped lens nucleus was removed through the corneal wound without using pars plana vitrectomy (PPV. After vitrectomy, the dropped lens nucleus was floated on the perfluorocarbon liquid (PFCL. The floating lens nucleus was then phacoemulsified and aspirated. During surgery, irrigation from the anterior chamber was performed. This method was very effective for treatment of a dropped hard nucleus.Case report: During cataract surgery on the left eye of an 80-year-old woman, a posterior capsule rupture occurred. As a result, the lens nucleus dropped into the vitreous cavity. Irrigation to the anterior chamber was performed, with an anterior chamber maintainer inserted through a newly created side port at the corneal limbus. A vitreous cutter and a light guide were inserted in order to perform vitrectomy through the corneal incisions that were created for the cataract surgery. After vitrectomy, the dropped lens nucleus was floated using PFCL. The floating lens nucleus was removed by a bimanual phacoemulsification technique, with the anterior chamber irrigation continuing. The separation of the irrigation port and the aspiration port allowed for effective treatment of the dropped nucleus that was floating on the PFCL, even using a ­phacoemulsification machine with a peristaltic pump system. Safe and effective vitrectomy, similar to a PPV, could be performed with this method using three corneal ports.Conclusion: This technique may allow safer and more effective treatment for a dropped lens nucleus compared with conventional PPV. With this technique, corneal distortion due to surgical manipulation can lead to reduced visibility of the posterior eye. Keywords: dislocated lens, transcorneal vitrectomy, bimanual

  18. Microstructural characterization and influence of manufacturing parameters on technological properties of vitreous ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Njoya, D. [Laboratoire de Physico-chimie des Materiaux Mineraux, Departement de Chimie Inorganique, Faculte des Sciences, Universite de Yaounde I, B.P. 812, Yaounde (Cameroon); Laboratoire de Physico-chimie des Materiaux et Environnement, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Hajjaji, M., E-mail: Hajjaji@ucam.ac.ma [Laboratoire de Physico-chimie des Materiaux et Environnement, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Bacaoui, A. [Laboratoire de Chimie Organique Appliquee, Departement de Chimie, Faculte des Sciences Semlalia, Universite Cadi Ayyad, B.P. 2390, Marrakech (Morocco); Njopwouo, D. [Laboratoire de Physico-chimie des Materiaux Mineraux, Departement de Chimie Inorganique, Faculte des Sciences, Universite de Yaounde I, B.P. 812, Yaounde (Cameroon)

    2010-03-15

    Microstructure of vitreous ceramic samples manufactured from kaolinitic-clay and feldspars raw materials from Cameroon was investigated in the range 1150-1250 deg. C by X-ray diffraction and scanning electron microscopy and by measuring some technological properties. Moreover, the simultaneous influence of feldspars content, heating temperature and soaking time on water absorption and firing shrinkage was evaluated by adopting the response surface methodology (Doehlert matrix), using the New Efficient Methodology for Research using Optimal Design (NEMROD) software. The results show that a spinel phase, mullite, glassy phase and some amount of hematite were formed. However, the spinel phase and potassic feldspar, as compared to the sodic one, disappeared at moderate firing temperature and soaking time. Apparently, mullite developed from spinel phase, which is formed from the demixion of metakaolin. On the other hand, it is found that the effects of fluxing content and firing temperature on the measured properties were almost similar and more influent than soaking time. Antagonistic and synergetic interactions existed between the considered parameters, and their importance differed for the considered properties. By using this mathematical tool, suitable operating conditions for manufacturing vitreous bodies were determined.

  19. Microstructural characterization and influence of manufacturing parameters on technological properties of vitreous ceramic materials

    International Nuclear Information System (INIS)

    Njoya, D.; Hajjaji, M.; Bacaoui, A.; Njopwouo, D.

    2010-01-01

    Microstructure of vitreous ceramic samples manufactured from kaolinitic-clay and feldspars raw materials from Cameroon was investigated in the range 1150-1250 deg. C by X-ray diffraction and scanning electron microscopy and by measuring some technological properties. Moreover, the simultaneous influence of feldspars content, heating temperature and soaking time on water absorption and firing shrinkage was evaluated by adopting the response surface methodology (Doehlert matrix), using the New Efficient Methodology for Research using Optimal Design (NEMROD) software. The results show that a spinel phase, mullite, glassy phase and some amount of hematite were formed. However, the spinel phase and potassic feldspar, as compared to the sodic one, disappeared at moderate firing temperature and soaking time. Apparently, mullite developed from spinel phase, which is formed from the demixion of metakaolin. On the other hand, it is found that the effects of fluxing content and firing temperature on the measured properties were almost similar and more influent than soaking time. Antagonistic and synergetic interactions existed between the considered parameters, and their importance differed for the considered properties. By using this mathematical tool, suitable operating conditions for manufacturing vitreous bodies were determined.

  20. Distribution of fluorescein sodium and triamcinolone acetonide in the simulated liquefied and vitrectomized Vitreous Model with simulated eye movements.

    Science.gov (United States)

    Stein, Sandra; Bogdahn, Malte; Rosenbaum, Christoph; Weitschies, Werner; Seidlitz, Anne

    2017-11-15

    Intravitreal administration is the method of choice for drug delivery to the posterior segment of the eye with special emphasis on the vitreous body and its surrounding retinal vasculature. In order to gain a better understanding of the underlying distribution processes, an in vitro model simulating the vitreous body (Vitreous Model, VM) and a system simulating the impact of movement on the VM (Eye Movement System, EyeMoS) was previously developed. In the study reported here, these systems were modified in regard to a standardized injection procedure, the diversity of simulated eye movements, extended periods of investigation, the opportunity to simulate the state after vitrectomy and in considering the physiological temperature. Fluorescein sodium (FS) and triamcinolone acetonide (TA) were used as (model) drugs to examine the drug distribution within the VM. Vitrectomy was simulated by replacing half the volume of the polyacrylamide gel that was used as vitreous substitute with the clinically used Siluron® 5000 whereas for a simulated liquefaction half the volume of the gel was replaced by buffer. A simulated liquefaction caused a 12-fold faster distribution of FS compared to the simulated juvenile VM, which was most likely caused by convective forces and mass transfer. Also, the injection technique (injection into the gel or into the buffer compartment) influenced the resulting distribution pattern. Without any liquefaction, the previously described initial injection channel occurred with both (model) drugs and, in the case of TA, remained almost unchanged during the investigation period of 72h. Simulating vitrectomized eyes, TA did not spread uniformly, but either remained in the depot or strongly sedimented within the VM suggesting that a homogenous distribution of a TA suspension is highly unlikely in vitrectomized eyes. High variabilities were observed with ex vivo animal eyes, demonstrating the limited benefit of explanted tissues for such distribution

  1. Single lens to lens duplication: The missing link

    OpenAIRE

    Bhatt, Rupal; Jethani, Jitendra; Saluja, Praveen; Bharti, Vinay

    2008-01-01

    Congenital anomalies of the lens include a wide range from lens coloboma to primary aphakia and doubling of lens. There have been few case reports of double lens; the etiology suggested is metaplastic changes in the surface ectoderm that leads to formation of two lens vesicles and hence resulting in double lens. We report a case with bilobed lens, which raises the possibility of explaining the etiology of double lens.

  2. Development of a Fresnel lens for cold neutrons based on neutron refractive optics

    International Nuclear Information System (INIS)

    Oku, T.; Morita, S.; Moriyasu, S.; Yamagata, Y.; Ohmori, H.; Takizawa, Y.; Shimizu, H.M.; Hirota, T.; Kiyanagi, Y.; Ino, T.; Furusaka, M.; Suzuki, J.

    2001-01-01

    We have developed compound refractive lenses (CRLs) for cold neutrons, which are made of vitreous silica and have an effective potential of (90.1-2.7x10 -4 i) neV. In the case of compound refractive optics, neutron absorption by the material deteriorates lens performance. Thus, to prevent an increase in neutron absorption with increasing beam size, we have developed Fresnel lenses using the electrolytic in-process dressing grinding technique. The lens characteristics were carefully investigated with experimental and numerical simulation studies. The lenses functioned as a neutron focusing lens, and the focal length of 14 m was obtained with a 44-element series of the Fresnel lenses for 10 A neutrons. Moreover, good neutron transmission of 0.65 for 15 A neutrons was obtained due to the shape effect. According to comprehensive analysis of the obtained results, it is possible to realize a CRL for practical use by choosing a suitable lens shape and material

  3. Effects of mechanical stress and vitreous samples in retinal pigment epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Eri, E-mail: eritakahashi@fc.kuh.kumamoto-u.ac.jp; Fukushima, Ayako; Haga, Akira; Inomata, Yasuya; Ito, Yasuhiro; Fukushima, Mikiko; Tanihara, Hidenobu

    2016-02-12

    In rhegmatogenous retinal detachment (RRD), scattered RPE cells from the basement membrane into the vitreous cavity undergo an epithelial mesenchymal transition (EMT) and form the intraocular fibrous membrane in response to vitreous fluid. We investigated whether exposure to vitreous samples was associated with EMT-associated signals and mesenchymal characters. Human vitreous samples were collected from patients with RRD, epiretinal membrane (ERM), or macular hole (MH). We evaluated the effects of vitreous on ARPE-19 cells in suspension cultures using poly 2-hydroxyethyl methacrylate-coated dishes and three-dimensional (3D) Matrigel cultures. We found that exposure to vitreous samples did not induce morphological changes or accelerate wound closure in monolayers. Several samples showed increased phosphorylation of Smad2 and nuclear translocation of nuclear factor-κB. Mechanical stress triggered an elevation of phosphorylation levels in Smad2. In addition, exposure to vitreous fluid increased the phosphorylation of p38 mitogen-activated protein kinase in cell suspension cultures after mechanical stress. Moreover, ARPE-19 cells showed a stellate invasive phenotype in 3D Matrigel cultures with vitreous samples. In this study, we demonstrated that mechanical stress and vitreous were associated with EMT-associated signals and invasive phenotypes in 3D cultures but not in monolayers. These results have important implications for the role of vitreous humor in the induction of EMT and intraocular fibrosis.

  4. Vitreous carbon mask substrate for X-ray lithography

    Science.gov (United States)

    Aigeldinger, Georg [Livermore, CA; Skala, Dawn M [Fremont, CA; Griffiths, Stewart K [Livermore, CA; Talin, Albert Alec [Livermore, CA; Losey, Matthew W [Livermore, CA; Yang, Chu-Yeu Peter [Dublin, CA

    2009-10-27

    The present invention is directed to the use of vitreous carbon as a substrate material for providing masks for X-ray lithography. The new substrate also enables a small thickness of the mask absorber used to pattern the resist, and this enables improved mask accuracy. An alternative embodiment comprised the use of vitreous carbon as a LIGA substrate wherein the VC wafer blank is etched in a reactive ion plasma after which an X-ray resist is bonded. This surface treatment provides a surface enabling good adhesion of the X-ray photoresist and subsequent nucleation and adhesion of the electrodeposited metal for LIGA mold-making while the VC substrate practically eliminates secondary radiation effects that lead to delamination of the X-ray resist form the substrate, the loss of isolated resist features, and the formation of a resist layer adjacent to the substrate that is insoluble in the developer.

  5. Application of ultrasound in the diagnosis of posterior vitreous detachment

    Directory of Open Access Journals (Sweden)

    Hui-Wei Wang

    2013-12-01

    Full Text Available AIM: To investigate the utility of ultrasound in the diagnosis of posterior vitreous detachment(PVD. METHODS: From September 2011 to September 2012, 506 eyes of 305 cases(male 191, female 114of PVD patients in our hospital were checked and analyzed with ultrasound.RESULTS: Totally, 179 eyes were diagnosed as partial PVD, the proportion was 35.4%. And 327 eyes were diagnosed as complete PVD, the proportion was 64.6%. Among the 61 eyes(12.1%with a small amount of hemorrhage of vitreous humor,retinal breaks of 26 eyes(5.1%were founded. Given the photocoagulation nicely heal to the breaks and then recovered. CONCLUSION:Ultrasonography can accurately diagnose PVD. It has non-invasive,convenience, and other characteristics, and it is worthy of clinical popularization.

  6. Contact Lens Care

    Science.gov (United States)

    ... Consumers Consumer Information by Audience For Women Contact Lens Care Share Tweet Linkedin Pin it More sharing ... www.fda.gov/medwatch Learn More about Contact Lens Care Other Tips on Contact Lenses Decorative Contact ...

  7. [Magnetic resonance imaging study of effects of accommodation on human lens morphological characters].

    Science.gov (United States)

    Zheng, Sui-lian; Zhang, Ai; Shi, Jian-jing; Zhou, Yun-xin

    2013-11-05

    To evaluate the effects of accommodation on lens morphological characters. From January 2011 to June 2011, magnetic resonance images of eyes were acquired from 30 subjects aged 20 to 24 years during accommodation and at rest. The optimal images were analyzed by Autocad 2010 to obtain the total lens cross-sectional area (CSA) and CSA of anterior and posterior portions of lens, anterior chamber depth, lens thickness, lens diameter, vitreous chamber depth and axial length during accommodation and at rest. Paired-t test was performed. The anterior curvature radius (mm), posterior curvature radius (mm), CSA of anterior portion (mm(2)), CSA of posterior portion (mm(2)), total lens CSA (mm(2)) was (8.7 ± 0.8), (6.2 ± 0.5), (7.5 ± 2.1), (12.0 ± 2.6), (20 ± 4) during relaxed accommodation; anterior curvature radius (mm), posterior curvature radius (mm), CSA of anterior portion (mm(2)), CSA of posterior portion (mm(2)), total lens CSA (mm(2)) was (7.1 ± 1.3), (5.6 ± 0.5), (14.7 ± 2.9), (12.2 ± 2.1) and (27 ± 4) during accommodation. The total lens CSA (t = -11.556, P 0.05) under a statistically independent accommodative state. There was significant difference in the anterior chamber depth (t = 4.366, P 0.05) and axial length (t = 0.418, P > 0.05) under accommodative states. During accommodation, the anterior chamber depth decreases, lens thickness increases and diameter of lens decreases while anterior portions and total lens CSA increase. There are insignificant changes in posterior portions of lens CSA, vitreous chamber depth and axial length. The accommodative changes in CSA indicate that the anterior portion of lens may be related with the properties of anterior capsule and lens material, the position of zonular attachments and the location of fetal nucleus. Helmholtz theory is supported.

  8. Radiation effects in vitreous and devitrified simulated waste glass

    International Nuclear Information System (INIS)

    Weber, W.J.; Turcotte, R.P.; Bunnell, L.R.; Roberts, F.P.; Westsik, J.H. Jr.

    1979-01-01

    The long-term radiation stability of vitreous and partially devitrified forms of high-level waste glass was investigated in accelerated experiments by 266 Cm doping. The effects of radiation on microstructure, phase behavior, density, impact strength, stored energy, and leachability are reported to a cumulative radiation dose of 5 x 10 18 α decays/cm 3 . This dose produces saturation of radiation effects in most properties. 4 figures

  9. An Unusual Case of Bilateral Vitreous Haemorrhage following Snake Bite

    Directory of Open Access Journals (Sweden)

    Vipul Bhandari

    2013-01-01

    Full Text Available A-45-year-old man presented to us with diminution of vision in both eye following snake bite. On examination vision in the right eye (RE was 6/36 and vision in left eye (LE was hand movement positive and fundus examination revealed a subhyloid haemorrhage, left eye showed vitreous haemorrhage. Patient was advised bed rest, vitamin C tablets and oral steroids.

  10. Usefulness of Discarded Vitreous Samples from Routine Vitrectomy

    Directory of Open Access Journals (Sweden)

    Natàlia Vilà

    2016-01-01

    Full Text Available Purpose. To describe the histopathological features of vitreous samples obtained after vitrectomy surgery from diabetic and nondiabetic patients. Methods. Vitreous specimens from 137 patients who underwent vitrectomy for different clinical conditions were analysed. All samples were centrifuged and each resulting pellet was fixed and processed as part of routine paraffin section histopathology. The histopathological features were categorized in a semiquantitative fashion. The samples from diabetic and nondiabetic patients were compared. Results. The 125 included patients (58 diabetic, 60% males were aged 64.2±13.9 years. The presence of hemorrhage, inflammatory cells, and histiocytes was significantly higher in the diabetic group (P<0.001, P=0.028, and P=0.016, resp., showing more vessels (P<0.001 and ghost vessels (P=0.049. The presence of inflammatory cells was the feature with the highest sensitivity for detecting diabetes mellitus (98% and also the highest negative predictive value (89%. In the multivariate analysis, three variables emerged as independent significant predictors of diabetes in vitrectomy samples: hemorrhage, endothelial-lined vessels, and age (P<0.001, P<0.001, and P=0.019, resp.. Conclusions. Different histopathological features can be found in vitreous samples from diabetic patients. Analysis of vitrectomy samples may serve as a tool for diabetes management.

  11. Clinical observation of two treatments for vitreous hemorrhage

    Directory of Open Access Journals (Sweden)

    He-Yi Li

    2014-08-01

    Full Text Available AIM: To investigate the indications and therapeutic effect of the conservative treatment and surgical treatment for vitreous hemorrhage.METHODS: Hemorrhage reasons, degree of illness, and treatment and final results of vitreous hemorrhage were recorded from 2008 to 2013, and curative effect of different treatments was analyzed.RESULTS: Selected 22 cases(24 eyesof conservative treatment, vision degree of 6 eyes(25%had raised, 5 eyes(21%occurred secondary retinal detachment without treatment, 3 eyes(12.5%suffered neovascular glaucoma were underwent operation, but the vision had lost completely. In 26 cases(31 eyesof control(operationgroup, vision of 17 eyes(55%had improved, 2 eyes(6.5%suffered the second operation, 2 eyes(6.5%suffered the third surgery, 3 eyes(10%suffered eyeball atrophy. The number of ultimate vision improved with conservative treatment were significantly lower than the number of cases with surgical treatment(PCONCLUSION: The surgical treatment is still visible vitreous hemorrhage treatment means of positive, but there will be eyeball atrophy and other serious complications, so we should choose a different methods in according to the different treatment objects and treatment time.

  12. Intravitreal Devices for the Treatment of Vitreous Inflammation

    Directory of Open Access Journals (Sweden)

    John B. Christoforidis

    2012-01-01

    Full Text Available The eye is a well-suited organ for local delivery of therapeutics to treat vitreous inflammation as well as other pathologic conditions that induce visual loss. Several conditions are particularly challenging to treat and often require chronic courses of therapy. The use of implantable intravitreal devices for drug delivery is an emerging field in the treatment of vitreous inflammation as well as other ophthalmologic diseases. There are unique challenges in the design of these devices which include implants, polymers, and micro- and nanoparticles. This paper reviews current and investigational drug delivery systems for treating vitreous inflammation as well as other pathologic conditions that induce visual loss. The use of nonbiodegradable devices such as polyvinyl alcohol-ethylene vinyl acetate polymers and polysulfone capillary fibers, and biodegradable devices such as polylactic acid, polyglycolic acid, and polylactic-co-glycolic acid, polycaprolactones, and polyanhydrides are reviewed. Clinically used implantable devices for therapeutic agents including ganciclovir, fluocinolone acetonide, triamcinolone acetonide, and dexamethasone are described. Finally, recently developed investigational particulate drug delivery systems in the form of liposomes, microspheres, and nanoparticles are examined.

  13. Aberration design of zoom lens systems using thick lens modules.

    Science.gov (United States)

    Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

    2014-12-20

    A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

  14. Investigating the micro-rheology of the vitreous humor using an optically trapped local probe

    Science.gov (United States)

    Watts, Fiona; Ean Tan, Lay; Wilson, Clive G.; Girkin, John M.; Tassieri, Manlio; Wright, Amanda J.

    2014-01-01

    We demonstrate that an optically trapped silica bead can be used as a local probe to measure the micro-rheology of the vitreous humor. The Brownian motion of the bead was observed using a fast camera and the micro-rheology determined by analysis of the time-dependent mean-square displacement of the bead. We observed regions of the vitreous that showed different degrees of viscoelasticity, along with the homogeneous and inhomogeneous nature of different regions. The motivation behind this study is to understand the vitreous structure, in particular changes due to aging, allowing more confident prediction of pharmaceutical drug behavior and delivery within the vitreous humor.

  15. Investigating the micro-rheology of the vitreous humor using an optically trapped local probe

    International Nuclear Information System (INIS)

    Watts, Fiona; Wright, Amanda J; Tan, Lay Ean; Wilson, Clive G; Girkin, John M; Tassieri, Manlio

    2014-01-01

    We demonstrate that an optically trapped silica bead can be used as a local probe to measure the micro-rheology of the vitreous humor. The Brownian motion of the bead was observed using a fast camera and the micro-rheology determined by analysis of the time-dependent mean-square displacement of the bead. We observed regions of the vitreous that showed different degrees of viscoelasticity, along with the homogeneous and inhomogeneous nature of different regions. The motivation behind this study is to understand the vitreous structure, in particular changes due to aging, allowing more confident prediction of pharmaceutical drug behavior and delivery within the vitreous humor. (paper)

  16. Forensic Analysis of a Contact Lens in a Murder Case.

    Science.gov (United States)

    Zwerling, Charles S

    2016-03-01

    Contact lenses have had rare relevance in trials and/or investigations. After 5 years of burial, orbital remnants were retrieved from an exhumed body and subsequently identified as a key piece of material evidence in a murder trial. The exhumed case materials were evaluated under laboratory conditions and were determined to be contact lens remnants. Contact lens fracture and burial simulation studies were performed to provide additional corroboration of the physical findings of the exhumed contact lens remnants. This material evidence was instrumental in providing factual proof refuting the defendant's testimony in the murder trial. A brief history of contact lens composition and use is provided for understanding the methods and observational results. This forensic case study represents the first published documentation of a contact lens from an exhumed body being used in a murder investigation and establishes an operational procedure for future forensic contact lens examinations. © 2016 American Academy of Forensic Sciences.

  17. [Detection of leptospira by culture of vitreous humor and detection of antibodies against leptospira in vitreous humor and serum of 225 horses with equine recurrent uveitis].

    Science.gov (United States)

    Dorrego-Keiter, Elisa; Tóth, József; Dikker, Lieke; Sielhorst, Jutta; Schusser, Gerald Fritz

    2016-01-01

    In the ongoing discussion regarding the aetiopathogenesis of equine recurrent uveitis (ERU) it was the aim of the present study to elucidate the relationship of leptospira infection and ERU. In a population of 225 horses leptospira were examined in vitreous humor by culture and leptospira antibody were detected in vitreous humor and serum samples. Preoperative serum samples were collected from 221/225 ERU patients of different age, gender and breed. Undiluted vitreous humor was aseptically taken from 198/225 patients that underwent pars plana vitrectomy at the beginning of surgery and from 27/225 patients' eyeball after enucleation: Serum and vitreous humor were tested for specific leptospiral antibodies by microscopic agglutination test (MAT). Furthermore, vitreous humor was examined by culture. 20 patients which were euthanized due to a live-threatening disease other than ERU served as a control group. A total of 127/221 (57.5%) horses had serum antibodies (≥ 1:100). Most frequently antibodies against L. interrogans serovar Grippotyphosa were detected (79/127), followed by L. interrogans serovar lcterohaemorrhagiae (34/127) and L. interrogans serovar Bratislava (29/127). Only 79/225 horses (35.1%) had leptospiral antibodies in vitreous humor, in which L. interrogans serovar Grippotyphosa (67/79) was identified most frequently followed by L. interrogans serovar Pomona (18/79) and L. interrogans serovar lcterohaemorrhagiae (8/79) which was identified as single or multiple reaction. Isolation of leptospira from vitreous humor was positive in 34/212 horses (16%). 10/20 control horses had a positive antibody titer against leptospira in serum and 2/20 horses in vitreous humor, whereas there was no leptospira detected in culture. The result of 84% negative cultures from vitreous humor of 212 ERU patients is decisive for the diagnosis and therapy of ERU.

  18. Synthetic vitreous fibers: a review toxicology, epidemiology and regulations.

    Science.gov (United States)

    Bernstein, David M

    2007-01-01

    This review addresses the characteristics which differentiate synthetic vitreous fibers (SVFs, e.g., fiber glass, stonewool, slagwool, refractory ceramic fibers, etc.), how these influence the potential biopersistence and toxicity, the most recent epidemiological results and the integration of these findings into the health and safety regulations in Europe and the United States. Also presented is the historical basis for the European classification directive. The use and equivalence of the chronic inhalation toxicology and chronic intraperitoneal injection studies in laboratory rodents for evaluation of fiber toxicology is assessed as well as the impact of dose selection and design on the validity of the study. While synthetic vitreous fibers can span a wide range of chemistries, recognition and understanding of the importance of biopersistence (ability to persist in the lung) in fiber toxicity has led to the development of more and more biosoluble fibers (that break down rapidly in the lung). Still, the epidemiological data available which are largely based upon the use of fibers in past decades, indicate that the SVF do not present a human health risk at current exposure levels. The animal toxicology and biopersistence data provide a coherent basis for understanding and evaluating the parameters which affect SVF toxicity. The current regulations are based upon an extensive knowledge base of chronic studies in laboratory rodents which confirm the relationship between chronic adverse effects and the biopersistence of the longer fibers that can not be fully phagocytised and efficiently cleared from the lung. The amorphous structure of synthetic vitreous fibers facilitates designing fibers in use today with low biopersistence. Both the epidemiological data and the animal studies database provide strong assurance that there is little if any health risk associated with the use of SVFs of low biopersistence. IARC (2001) reclassified these fibers from Category 2b to

  19. Minimum additive waste stabilization using vitreous ceramics. Progress report, October 1994--September 1995

    International Nuclear Information System (INIS)

    Feng, X.; Hahn, W.K.; Gong, M.; Gong, W.; Wang, L.; Ewing, R.C.

    1995-01-01

    Vitreous ceramic waste forms are being developed at Pacific Northwest Laboratory to complement glass waste forms in implementing the Minimum Additive Waste Stabilization (MAWS) Program to support the US Department of Energy's environmental restoration efforts. These vitreous ceramics are composed of various metal-oxide crystalline phases embedded in a silicate-glass phase. This work extends the success of vitreous ceramic waste forms to treat wastes with both high metal and high alkali contents. Two successful approaches are discussed: developing high-durability alkali-binding crystals in a durable glassy matrix, and developing water-soluble crystals in a durable and continuous glassy matrix. Nepheline-vitreous ceramics were demonstrated for the immobilization of high-alkali wastes with alkali contents up to 21 wt%. The chemical durability of the nepheline-vitreous ceramics is better than the corresponding glasses, especially in over longer times. Vitreous ceramics with Cs 2 O loading up to 35.4 wt% have been developed. Vitreous ceramic waste forms were developed from 90 and 100% Oak Ridge National Laboratory K-25 pond sludge. Heat treatment resulted in targeted crystal formation of spinels, potassium feldspar, and Ca-P phases. The K-25 pond sludge vitreous ceramics were up to 42 times more durable than high-level environmental assessments (EA) glass. The toxicity characteristics leach procedure (TCLP) concentration of LVC-6 is at least 2,000 times lower than US Environmental Protection Agency limits. Idaho Chemical Process Plant (ICPP) calcined wastes were immobilized into vitreous ceramics with calcine loading up to 88%. These ICPP-vitreous ceramics were more durable than the EA glass by factors of 5 to 30. Vitreous ceramic waste forms are being developed to complement, not to replace, glass waste forms

  20. Analysis of causes of intraocular lens explantations in the material of Department of Ophthalmology, Medical University of Lodz.

    Science.gov (United States)

    Wilczyński, Michał; Wilczyńska, Olena; Omulecki, Wojciech

    2009-01-01

    Implantation of intraocular lenses (IOLS) has become a standard practice in cataract surgery, however, similar to any other type of surgery, using IOLs is not complication-free and sometimes explantation of intraocular lenses may be necessary. This study was to gather data and analyze causes of intraocular lens explantations, performed in the Department of Ophthalmology, Medical University of Łódź. The data were gathered from medical documentation of all patients who underwent intraocular lens removal from January 2003 to July 2006. The examined group consisted of 16 patients (16 eyes): 9 women (fraction 0.56), and 7 men (fraction 0.44), at the age from 21 to 82 years (mean age 62.4 years, SD +/- 15.5). In all patients IOL explantation was performed under local, peribulbar anaesthesia. Two groups of patients were distinguished: patients who had an anterior chamber lens explanted (3 patients, fraction 0.19) and patients who underwent posterior chamber lens explantation (13 patients, fraction 0.81). Causes of AC IOL explantations were: vaulting of the IOL (1 eye, fraction 0.06), luxation of the IOL to the vitreous cavity (1 eye, fraction 0.06), and painful eyeball after anterior chamber lens implantation (1 eye, fraction 0.06). Causes of PC IOL explantations were: subluxation of the IOL (6 eyes, fraction 0.38), luxation of the lens to the vitreous cavity (3 eyes, fraction 0.19), luxation of the lens to the anterior chamber (1 eye, fraction 0.06), endophthalmitis (2 eyes, fraction 0.13) and incorrect lens power (1 eye, fraction 0.06). In the majority of eyes (n = 13, fraction 0.81) the removed implant was replaced by another intraocular lens, but 3 eyes (fraction 0.19) were left aphakic. We did not observe serious intra- or early postoperative complications which might influence the final result of the operation.

  1. Refractive neutron lens

    International Nuclear Information System (INIS)

    Petrov, P.V.; Kolchevsky, N.N.

    2013-01-01

    Model of the refractive neutron lens is proposed. System of N lenses acts as one thin lens with a complex refraction index n*. The maximum number N max of individual lenses for 'thick' neutron lens is calculated. Refractive neutron lens properties (resolution, focal depth) as function of resolution factor F 0 =ρbc/μ and depth of field factor dF 0 =λF 0 =λρbc/μ are calculated. It is shown that micro resolution of the refractive neutron optics is far from the wavelength in size and its open possibilities for progress in refractive neutron optics. (authors)

  2. Vitreous hemorrhage as a clue to late presenting Pulmonary Arterio Venous Malformation

    Directory of Open Access Journals (Sweden)

    Brijesh Takkar

    2017-10-01

    Full Text Available Retinal vasculature is frequently altered in systemic vascular disorders such as Diabetes and Hypertension. We present a rare case in which vitreous hemorrhage was the presenting sign of an underlying congenital cyanotic heart disease. Keywords: Vitreous hemorrhage, Cyanotic heart disease, Conjunctival telangiectasia

  3. Electrochemical behaviour of uranium (IV) in DMF at vitreous carbon

    International Nuclear Information System (INIS)

    Afonso, M.L.; Gomes, A.; Carvalho, A.; Alves, L.C.; Wastin, F.; Goncalves, A.P.

    2009-01-01

    The electrochemical behaviour of UCl 4 (0.01 mol L -1 up to 0.05 mol L -1 ) in 0.1 mol L -1 TBAPF 6 /DMF solution at vitreous carbon was studied, at room temperature, by cyclic voltammetry and potentiostatic techniques. The electrolytic solutions were analyzed by UV spectroscopy (UV), and the electrodeposited films were characterized by Rutherford Backscattering Spectroscopy (RBS) and X-ray diffraction (XRD). The cyclic voltammetric results, at low UCl 4 concentrations (0.01 mol L -1 ), point that the reduction of U(IV) to U(0) occurs in two steps involving mainly U(IV) and U(III) species. The first electron transfer reaction is quasi-reversible and the second irreversible. The diffusion coefficient of U(IV) in DMF and the charge rate constant were determined to be 4.78 x 10 -7 cm 2 s -1 and 1.93 x 10 -3 cm s -1 (at 0.02 V s -1 ), respectively. RBS data obtained from samples prepared at constant potential (-3.10 V) during 3 h at room temperature, indicated the presence of uranium particles deposited all over the vitreous carbon surface with aggregates in some places, confirming that the second reduction step corresponds to uranium electrodeposition. No crystallographic ordering could be seen by XRD, pointing to an amorphous character of the uranium films.

  4. CONTACT LENS RELATED CORNEAL ULCER

    Directory of Open Access Journals (Sweden)

    AGARWAL P

    2010-01-01

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

  5. Capsular 'pits' in the human lens.

    OpenAIRE

    Harris, M. L.; Brown, N. A.; Shun-Shin, G. A.; Smith, G. T.

    1992-01-01

    The lens capsule is an atypical basement membrane surrounding the lens epithelial cells and lens fibres which make up the remainder of the human lens. A seemingly unreported morphological change visible in the lens capsule with the biomicroscope is described.

  6. Negative effects of transthyretin in high myopic vitreous on diabetic retinopathy

    Directory of Open Access Journals (Sweden)

    Jun Shao

    2017-12-01

    Full Text Available AIM: To analyze the relationship between vitreous transthyretin (TTR levels, high myopia and diabetic retinopathy (DR. METHODS: We selected 6722 individuals from the southern Jiangsu Province for diabetes and ophthalmic examinations. The TTR concentration in the vitreous of 50 patients with high myopia and diabetes, 50 patients with only DR, and 20 healthy controls were determined by ELISA. Key factors in Tie2 pathway in DR development including vascular endothecial growth factor (VEGF, Tie2, Angpt1, Angpt2, vascular endothelial growth factor receptor (VEGFR 1 and VEGFR2 were also detected by ELISA. RESULTS: The prevalence of DR in patients with diabetes and myopia [6.00 D, and diabetes without myopia were 11.1%, 2.5%, and 60.0%, respectively. The vitreous TTR concentration of patients with diabetes and high myopia was approximately 6.5- and 4.2-times higher than those of patients with DR and healthy controls, respectively (P<0.05. Following the vitreous TTR concentration, the levels of VEGF, Tie2, Angpt1, Angpt2, VEGFR1 and VEGFR2 in vitreous of diabetes and high myopia patients, DR patients and healthy controls were detected as dramatically fluctuated. CONCLUSION: The results suggest that TTR can affect the vitreous contents of key factors in Tie2 pathway for neovascularization, and there should be a protective association between abundant TTR levels in the vitreous of highly myopic patients and a decreased risk of DR.

  7. Synchrotron radiation analysis on ancient Egyptian vitreous materials

    International Nuclear Information System (INIS)

    Yamahana, Kyoko

    2000-01-01

    Ancient Egyptian vitreous materials, namely faience and glass, share the same elemental composition. But they appear to have originated separately. Faience objects appear as early as the Predynastic period, and glass was introduced from Mesopotamia during the New Kingdom. These faience and glass objects were not of daily use, rather they were regarded as religious symbols or luxury status goods. Most of the products were coloured blue, but we see an increased use of other colours during the New Kingdom (c.1550-1069BC). This tendency corresponds to the period of both territorial and political expansion of Egypt. A non-destructive SR-XRF experiment at SPring-8 was conducted last winter, aiming to determine the regional trait of elemental composition by examining the pattern and ratio of rare earth elements. As a result, we could observe some distinctive rare earth elements that may indicate regional variation. (author)

  8. Borides and vitreous compounds sintered as high-energy fuels

    International Nuclear Information System (INIS)

    Mota, J.M.; Abenojar, J.; Martinez, M.A.; Velasco, F.; Criado, A.J.

    2004-01-01

    Boron was chosen as fuel in view of its excellent thermodynamic values for combustion, as compared to traditional fuels. The problem of the boron in combustion is the formation of a surface layer of oxide, which delays the ignition process, reducing the performance of the rocket engine. This paper presents a high-energy fuel for rocket engines. It is composed of sintered boron (borides and carbides and vitreous compounds) with a reducing chemical agent. Borides and boron carbide were prepared since the combustion heat of the latter is similar to that of the amorphous boron (in: K.K. Kuo (Ed.), Boron-Based Solid Propellant and Solid Fuel, Vol. 427, CRC Press, Boca Raton, FL, 1993). Several chemical reducing elements were used, such as aluminum, magnesium, and coke. As the raw material for boron, different compounds were used: amorphous boron, boric acid and boron oxide

  9. Synchrotron radiation analysis on ancient Egyptian vitreous materials

    Energy Technology Data Exchange (ETDEWEB)

    Yamahana, Kyoko [Tokai Univ., Hiratsuka, Kanagawa (Japan). Lecture of Egyptian Archaeology

    2000-07-01

    Ancient Egyptian vitreous materials, namely faience and glass, share the same elemental composition. But they appear to have originated separately. Faience objects appear as early as the Predynastic period, and glass was introduced from Mesopotamia during the New Kingdom. These faience and glass objects were not of daily use, rather they were regarded as religious symbols or luxury status goods. Most of the products were coloured blue, but we see an increased use of other colours during the New Kingdom (c.1550-1069BC). This tendency corresponds to the period of both territorial and political expansion of Egypt. A non-destructive SR-XRF experiment at SPring-8 was conducted last winter, aiming to determine the regional trait of elemental composition by examining the pattern and ratio of rare earth elements. As a result, we could observe some distinctive rare earth elements that may indicate regional variation. (author)

  10. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Mike A. (Albuquerque, NM); Foreman, Larry R. (Los Alamos, NM)

    1997-01-01

    This invention describes a method for fabricating an intraocular lens made rom clear Teflon.TM., Mylar.TM., or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube.

  11. Intraocular lens fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, M.A.; Foreman, L.R.

    1997-07-08

    This invention describes a method for fabricating an intraocular lens made from clear Teflon{trademark}, Mylar{trademark}, or other thermoplastic material having a thickness of about 0.025 millimeters. These plastic materials are thermoformable and biocompatable with the human eye. The two shaped lenses are bonded together with a variety of procedures which may include thermosetting and solvent based adhesives, laser and impulse welding, and ultrasonic bonding. The fill tube, which is used to inject a refractive filling material is formed with the lens so as not to damage the lens shape. A hypodermic tube may be included inside the fill tube. 13 figs.

  12. Ligands and modifiers in vitreous materials the spectroscopy of condensed systems

    CERN Document Server

    Margaryan, Alfred

    1999-01-01

    The study of the effect of ligand and modifier ions on the spectroscopic properties of dn or fn elements in vitreous materials is important for the development of controllable lasers and amplifiers. The spectroscopic characteristics of inorganic compounds of transition elements and their solutions are well understood theoretically in the spectrochemistry of complexes, but developments for vitreous materials in these conditions have not been well documented. This book fills the gap by applying the ligand field theory of solid materials to the vitreous state, and presenting the data obtained fro

  13. Thermal Transformations of Iron Cations in the System Metal-Vitreous Enamel Coat. Moessbauer Spectroscopic Study

    International Nuclear Information System (INIS)

    Barcova, K.; Mashlan, M.; Zboril, R.; Hrabovska, K.

    2005-01-01

    Vitreous enameling on steel is carried out to provide a protective layer against chemical corrosion from the surrounding environment. The glass bonds with the steel to form a composite material. The Moessbauer spectroscopy was firstly applied to study the vitreous enameling in which the complex of processes, as diffusion of species, adhesion between the glass and the steel, galvanic reactions, plays an important role. The Moessbauer spectroscopy provides unique information about the Fe-phase structure of the vitreous enamel layer and that of the steel-enamel interface. Diffusion of iron from steel surface towards enamel layer and formation of a new Fe2+ phase was proved

  14. RESEARCH OF LINEAR AND NONLINEAR PROCESSES AT FEMTOSECOND LASER RADIATION PROPAGATION IN THE MEDIUM SIMULATING THE HUMAN EYE VITREOUS

    Directory of Open Access Journals (Sweden)

    P. Y. Rogov

    2015-09-01

    Full Text Available The paper deals with mathematical model of linear and nonlinear processes occurring at the propagation of femtosecond laser pulses in the vitreous of the human eye. Methods of computing modeling are applied for the nonlinear spectral equation solution describing the dynamics of a two-dimensional TE-polarized radiation in a homogeneous isotropic medium with cubic fast-response nonlinearity without the usage of slowly varying envelope approximation. Environments close to the optical media parameters of the eye were used for the simulation. The model of femtosecond radiation propagation takes into account the process dynamics for dispersion broadening of pulses in time and the occurence of the self-focusing near the retina when passing through the vitreous body of the eye. Dependence between the pulse duration on the retina has been revealed and the duration of the input pulse and the values of power density at which there is self-focusing have been found. It is shown that the main mechanism of radiation damage with the use of titanium-sapphire laser is photoionization. The results coincide with those obtained by the other scientists, and are usable for creation Russian laser safety standards for femtosecond laser systems.

  15. Vitreous haemorrhage in massive hemorrhagic polypoidal choroidal vasculopathy: clinical characteristics and surgical outcomes: Vitreous hemorrhage in PCV.

    Science.gov (United States)

    Narayanan, Raja; Mithal, Kopal; Jalali, Subhadra; Chhablani, Jay Kumar; Mathai, Annie; Ali, Md Hasnat

    2015-01-01

    To report the outcomes of vitreous hemorrhage (VH) associated with hemorrhagic polypoidal choroidal vasculopathy (PCV). A retrospective study of 28 eyes of 27 consecutive patients of hemorrhagic PCV with VH, which were managed surgically between January 2003 and December 2011, was performed. All patients underwent pars plana vitrectomy for VH associated with PCV. The main outcome measure was best-corrected visual acuity (BCVA) at baseline, at 1, 3 and 6 months post operatively and at last follow up. The visual acuity measured on early treatment diabetic retinopathy study (ETDRS) chart improved in 16 eyes (57.1 %) by two or more lines, remained unchanged in nine eyes (32.1 %) and decreased in three (10.7 %) after surgery when compared to baseline VA. The mean baseline VA was 2.69 ± 0.57 logMAR units (hemorrhagic PCV have sustained improvement in visual acuity following surgery.

  16. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... Costume Contact Lenses Can Ruin Vision Eye Makeup Safety In fact, it is illegal to sell colored ...

  17. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... new application of artificial intelligence shows whether a patient’s eyes point to high blood pressure or risk ...

  18. The lens and cataracts.

    Science.gov (United States)

    Matthews, Andrew G

    2004-08-01

    It is conservatively estimated that some form of lens opacity is present in 5% to 7% of horses with otherwise clinically normal eyes.These opacities can range from small epicapsular remnants of the fetal vasculature to dense and extensive cataract. A cataract is defined technically as any opacity or alteration in the optical homogeneity of the lens involving one or more of the following: anterior epithelium, capsule, cortex, or nucleus. In the horse, cataracts rarely involve the entire lens structure (ie, complete cataracts) and are more usually localized to one anatomic landmark or sector of the lens. Complete cataracts are invariably associated with overt and significant visual disability. Focal or incomplete cataracts alone seldom cause any apparent visual dysfunction in affected horses,however.

  19. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... One Use Facts About Colored Contacts and Halloween Safety Colored Contact Lens Facts Over-the-Counter Costume ... use of colored contact lenses , from the U.S. Food and Drug Administration (FDA). Are the colored lenses ...

  20. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her ...

  1. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... contacto de color Sep. 26, 2013 It started as an impulsive buy from a souvenir shop, but ... require the same level of care or consideration as a standard contact lens because they can be ...

  2. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... With Proper Contact Lens Care Apr 23, 2018 Solar Eclipse Inflicts Damage in the Shape of the ... edging closer, thanks to a wave of new technologies aiming to fix failing eye parts with human- ...

  3. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... glow-in-the-dark lizard lenses, costume contacts can certainly add a spooky, eye-popping touch. But ... consideration as a standard contact lens because they can be purchased over-the-counter or on the ...

  4. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... valid prescription that includes the brand name, lens measurements, and expiration date. Purchase the colored contact lenses ... with human-made versions. U.S. News Highlights the Value of Ophthalmologists APR 20, 2018 By Dan T. ...

  5. Vortex gas lens

    Science.gov (United States)

    Bogdanoff, David W.; Berschauer, Andrew; Parker, Timothy W.; Vickers, Jesse E.

    1989-01-01

    A vortex gas lens concept is presented. Such a lens has a potential power density capability of 10 to the 9th - 10 to the 10th w/sq cm. An experimental prototype was constructed, and the divergence half angle of the exiting beam was measured as a function of the lens operating parameters. Reasonably good agreement is found between the experimental results and theoretical calculations. The expanded beam was observed to be steady, and no strong, potentially beam-degrading jets were found to issue from the ends of the lens. Estimates of random beam deflection angles to be expected due to boundary layer noise are presented; these angles are very small.

  6. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... had not been properly fitted by an eye care professional, the lenses stuck to my eye like ... lenses do not require the same level of care or consideration as a standard contact lens because ...

  7. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... sell contacts without a prescription are breaking the law, and may be fined $11,000 per violation. " ...

  8. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... not require the same level of care or consideration as a standard contact lens because they can ... Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms ...

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. ...

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. Follow the contact lens care directions for cleaning, disinfecting, and wearing the lenses. Never share contact ... with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology Job Center © American ...

  11. Pars-plana fluid aspiration for positive vitreous cavity pressure in anterior segment surgeries

    Directory of Open Access Journals (Sweden)

    Thomas Kuriakose

    2018-01-01

    Full Text Available Positive vitreous pressure due to misdirection of aqueous or choroidal effusion leads to shallowing of the anterior chamber (AC before or during anterior segment surgeries. This shallow AC if not addressed makes surgery difficult and increases the risk of surgical complications. Methods to prevent and manage this condition described in literature are not without problems. We describe a minimally invasive technique of passing a 30G needle through the pars-plana to aspirate misdirected fluid from vitreous cavity either as a prophylaxis just before surgery or during it, thereby decreasing positive vitreous pressure. This technique, used in 12 eyes, seems to be effective in patients with angle-closure glaucoma, malignant glaucoma, and per-operative sudden increase in vitreous pressure during surgery. Small-incision surgeries are ideally suited for this procedure. This minimally invasive technique is simple to perform and complications are unlikely to be more than what is seen with intravitreal injections.

  12. Evidence for vitreous type orientational ordering in solid hydrogen and deuterium

    International Nuclear Information System (INIS)

    Devoret, M.

    1982-09-01

    This shown a new region in the concentration-temperature phase diagram for solid mixtures of ortho and para-hydrogen. This region is characterized by a vitreous type orientational, ordering, with the quadrupoles of the ortho molecules frozen in a random fashion. This new vitreous state is called a quadrupolar glass, with the degrees of freedom of quadrupolar moments frozen in solid hydrogen [fr

  13. Vitreous occlusion of tube implant in a phakic patient with traumatic glaucoma

    Directory of Open Access Journals (Sweden)

    Suneeta Dubey

    2014-01-01

    Full Text Available Tube implants or glaucoma drainage devices have become an important method of intraocular pressure reduction when treating complex cases of traumatic glaucoma. However, it is not uncommon to have complications associated with tube implants. The optimal treatment of patients who have undergone glaucoma implant surgery complicated by vitreous incarceration is uncertain. If vitreous is present or is able to prolapse into anterior chamber, as in aphakic or pseudophakic patient without an intact posterior capsule, a concurrent anterior vitrectomy is usually performed. In such cases, pars plana vitrectomy has been found to be more effective in several studies. However, there are no set guidelines for management of such a case in a phakic eye and the management can be more challenging especially when there is no obvious deficiency in posterior capsule, zonular dialysis, or loose vitreous gel in the anterior chamber prior to or during tube implantation. We describe a case of 14-year-old phakic patient with traumatic glaucoma without vitreous gel in anterior chamber whose tube implant became occluded by vitreous resulting in increased intra ocular pressure. This is the first documented report of vitreous incarceration in a phakic patient and its successful management.

  14. Tangential vitreous traction: a possible mechanism of development of cystoid macular edema in retinitis pigmentosa

    Directory of Open Access Journals (Sweden)

    Mikiko Takezawa

    2011-02-01

    Full Text Available Mikiko Takezawa, Soichi Tetsuka, Akihiro KakehashiDepartment of Ophthalmology, Jichi Medical University, Saitama Medical Center, Saitama, Saitama, JapanAbstract: We report the possible mechanism of development of cystoid macular edema (CME in retinitis pigmentosa (RP in the case of a 68-year-old woman with RP and CME in the right eye and resolving CME in the left eye. Spectral domain optical coherence tomography showed CME and posterior vitreoschisis in the nasal quadrant of the fundus without a posterior vitreous detachment (PVD. This vitreous pathology suggested bilateral thickening and shrinkage of the posterior vitreous cortex. In the right eye, CME was evident with no vitreofoveal separation. However, in the left eye, minimal change was seen in the CME associated with a focal shallow PVD over the fovea. The best-corrected visual acuity (BCVA in the left eye increased to 0.3 from 0.15 7 years after the first visit. Tangential vitreous traction on the macula may have caused the CME in the right eye. The shallow PVD over the fovea might have released the tangential vitreous traction from the fovea, induced spontaneous resolution of the CME, and improved the BCVA in the left eye.Keywords: retinitis pigmentosa, cystoid macular edema, posterior vitreous detachment, posterior vitreoschisis, optical coherence tomography

  15. An Assessment of Vitreous Degeneration in Eyes with Vitreomacular Traction and Macular Holes

    Directory of Open Access Journals (Sweden)

    Quraish Ghadiali

    2017-01-01

    Full Text Available Purpose. To compare the stages of vitreous degeneration in patients with vitreomacular traction (VMT and macular holes (MH. Methods. A retrospective study was performed analyzing stages of vitreous degeneration of eyes with VMT or MH using swept-source optical coherence tomography (SS-OCT and spectral-domain optical coherence tomography (SD-OCT. An analogous review was performed on a control group of eyes with contralateral posterior vitreous detachments. Thirty-four eyes with VMT/MH and 39 control eyes were reviewed. Results. Twenty-seven VMT/MH eyes and 31 control eyes were included. Eyes with VMT/MH demonstrated significantly earlier stages of vitreous degeneration when compared to the control group (p=0.048 despite significantly greater age (p=0.032. Conclusions. Vitreoretinal interface disease is more often associated with a formed vitreous and an intact premacular bursa. This is contrary to previous assumptions implicating degeneration of vitreous as a precipitating factor of interface disease when in conjunction with abnormal vitreomacular separation.

  16. Vitreous flow rates through dual pneumatic cutters: effects of duty cycle and cut rate

    Directory of Open Access Journals (Sweden)

    Abulon DJK

    2015-02-01

    Full Text Available Dina Joy K Abulon Medical Affairs, Alcon Research, Ltd, Lake Forest, CA, USA Purpose: We aimed to investigate effects of instrument settings on porcine vitreous flow rates through dual pneumatic high-speed vitrectomy probes. Methods: The CONSTELLATION® Vision System was tested with 250, 450, and 650 mmHg of vacuum using six ULTRAVIT® vitrectomy probes of each diameter (25+®, 25, 23, and 20 gauge operated from 500 cuts per minute (cpm up to 5,000 cpm. Duty cycle modes tested included biased open, 50/50, and biased closed. Flow rates were calculated by assessing the change in weight of porcine eyes during vitreous aspiration. Volumetric flow rate was measured with a computer-connected electronic scale. Results: At lower cut rates, the biased open mode produced higher flow than did the 50/50 mode, which produced higher flow than did the biased closed mode. In the biased closed and 50/50 modes, vitreous flow rates tended to increase with increasing cut rate. Vitreous flow rates in the biased open duty cycle mode remained relatively constant across cut rates. Conclusion: Vitreous flow rates through dual pneumatic vitrectomy probes could be manipulated by changing the duty cycle modes on the vitrectomy system. Differences in duty cycle behavior suggest that high-speed cut rates of 5,000 cpm may optimize vitreous aspiration. Keywords: enhanced 25-gauge vitrectomy, 25-gauge vitrectomy, 20-gauge vitrectomy, 23-gauge vitrectomy, aspiration, Constellation Vision System

  17. Bromatological characteristics and ruminal digestibility of grain corn hybrids with different vitreousness in silage maturity

    Directory of Open Access Journals (Sweden)

    Evandrei Santos Rossi

    2016-06-01

    Full Text Available The aim of this research was to evaluate vitreousness in commercial corn hybrids with flint and dent grains and to study the effect of this characteristic on agronomic behavior, nutritional value, and ruminal degradability of grains harvested in silage maturity. Twelve commercial corn hybrids were evaluated. They were divided in two groups (six with flint grains and six with dent grains. The experiments were conducted in two municipalities represented by Guarapuava and Laranjeiras do Sul, both in Paraná State. The harvest for the grain quality analysis was performed at ¾ of the milk line stage in the grain. The following characteristics were evaluated: grain yield, grain yield in silage maturity, vitreousness, ruminal digestibility of grain, neutral detergent fiber, acid detergent fiber and crude protein. The grains in the group of dent hybrids exhibited better degradability associated with lower vitreousness than the group of flint hybrids. The group of dent hybrids exhibited better ruminal digestibility of the grains associated with lower vitreousness versus the group of flint hybrids. There is a negative correlation between vitreousness and the digestibility of the grain; thus, vitreousness can be a criterion for selecting genotypes for forage production.

  18. Symmetric lens with extended depth of focus

    OpenAIRE

    Cho, Sung Nae

    2008-01-01

    The lens surface profile is derived based on the instantaneous focal length versus the lens radius data. The lens design based on instantaneous focal length versus the lens radius data has many useful applications in software assisted image focusing technology.

  19. A catoptric lens

    International Nuclear Information System (INIS)

    Rambauske, W.R.

    1973-01-01

    The invention relates to a catoptric lens for combining energies transmitted by several sources such as lasers; said lens comprising mirrors, the reflective surfaces of which have their focuses spaced from a common axis of symmetry. By means of these reflecting surfaces, which are generated by the nutation of portions of quadratic conics about the axis of symmetry, it is possible to focus the energy emmited by several lasers at the focus of the exit-mirror reflecting surface. This can be applied to thermonuclear fusion [fr

  20. A Case of Syphilitic Uveitis in Which Vitreous Surgery Was Useful for the Diagnosis and Treatment

    Directory of Open Access Journals (Sweden)

    Takatoshi Kobayashi

    2017-01-01

    Full Text Available Purpose: To report a case of atypical syphilitic uveitis complicated with retinal vasculitis, proliferative retinopathy, and vitreous hemorrhage in which vitreous surgery was useful for the diagnosis and treatment. Case Report: A 38-year-old female was referred to our hospital after noticing visual disturbance in her right eye. Fundoscopy examination of that eye revealed retinal phlebitis accompanied by retinal hemorrhage and soft exudate, and remarkable exudative changes in the retinal vessels from the upper arcade to the macula region. After a blood examination, a serological test showed positive for syphilis; however, systemic findings were scarce. Syphilitic uveitis was suspected, so we administered treatment for syphilis, anticoagulant treatment for retinal vasculitis, steroids for intraocular inflammation, and photocoagulation for the retinal nonperfusion area. However, her visual acuity (VA decreased to 30 cm/counting fingers due to vitreous hemorrhage resulting from fibrovascular membrane at the optic disc. Since the vitreous hemorrhage was insufficiently absorbed, vitreous surgery was performed to remove the hemorrhage and fibrovascular tissue. Following surgery, the uveitis and retinal vasculitis subsided, and her corrected VA improved to 0.3. Postoperative examination of a fixed quantity of collected vitreous fluid for syphilis showed a Treponema pallidum hemagglutination value of 5,120 times the normal amount, thus confirming the syphilitic uveitis diagnosis. Conclusions: Our findings show that when observing patients with obstructive retinal vasculitis of unknown causes, syphilitic uveitis should be considered as a differential diagnosis, and that vitreous surgery is useful for the diagnosis and treatment of atypical syphilitic uveitis which has progressed to proliferative retinopathy.

  1. A Tribute to Len Barton

    Science.gov (United States)

    Tomlinson, Sally

    2010-01-01

    This article constitutes a short personal tribute to Len Barton in honour of his work and our collegial relationship going back over 30 years. It covers how Len saw his intellectual project of providing critical sociological and political perspectives on special education, disability and inclusion, and his own radical political perspectives. Len's…

  2. Luneburg lens in silicon photonics.

    Science.gov (United States)

    Di Falco, Andrea; Kehr, Susanne C; Leonhardt, Ulf

    2011-03-14

    The Luneburg lens is an aberration-free lens that focuses light from all directions equally well. We fabricated and tested a Luneburg lens in silicon photonics. Such fully-integrated lenses may become the building blocks of compact Fourier optics on chips. Furthermore, our fabrication technique is sufficiently versatile for making perfect imaging devices on silicon platforms.

  3. Intraocular foreign-body hazard during vitrectomy.

    Science.gov (United States)

    Bovino, J A; Marcus, D F

    1982-03-01

    We noted two instances of forceps-induced fragmentation of the bar used for scleral plug storage during vitreous surgery. The silicone bar material was adherent to the plug in both cases. Because this represents a significant intraocular foreign body hazard, the scleral plug should be carefully inspected before insertion.

  4. Respiratory health effects of man-made vitreous (mineral) fibres.

    Science.gov (United States)

    De Vuyst, P; Dumortier, P; Swaen, G M; Pairon, J C; Brochard, P

    1995-12-01

    The group of man-made mineral or vitreous fibres (MMMFs or MMVFs) includes glass wool, rock wool, slag wool, glass filaments and microfibres, and refractory ceramic fibres (RCFs). Experimental observations have provided evidence that some types of MMVF are bioactive under certain conditions. The critical role of size parameters has been demonstrated in cellular and animal experiments, when intact fibres are in direct contact with the target cells. It is, however, difficult to extrapolate the results from these studies to humans since they bypass inhalation, deposition, clearance and translocation mechanisms. Inhalation studies are more realistic, but show differences between animal species regarding their sensibility to tumour induction by fibres. Fibre biopersistence is an important factor, as suggested by recent inhalation studies, which demonstrate positive results with RCF for fibrosis, lung tumours and mesothelioma. There is no firm evidence that exposure to glass-, rock- and slag wool is associated with lung fibrosis, pleural lesions, or nonspecific respiratory disease in humans. Exposure to RCF could enhance the effects of smoking in causing airways obstruction. An elevated standard mortality ratio for lung cancer has been demonstrated in cohorts of workers exposed to MMVF, especially in the early technological phase of mineral (rock slag) wool production. During that period, several carcinogenic agents (arsenic, asbestos, polycyclic aromatic hydrocarbons (PAH)) were also present at the workplace and quantitative data about smoking and fibre levels are lacking. It is not possible from these data to determine whether the risk of lung cancer is due to the MMVFs themselves. No increased risk of mesothelioma has been demonstrated in the cohorts of workers exposed to glass-, slag- or rock wool. There are in fact insufficient epidemiological data available concerning neoplastic diseases in RCF production workers because of the small size of the workforce and the

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into the cornea. Even if you have perfect vision, you need to get an eye exam and a prescription ...

  6. Contact Lens Risks

    Science.gov (United States)

    ... There is a risk of eye infection from bacteria in swimming pool water, hot tubs, lakes and the ocean Replace your contact lens storage case every 3 months or as directed by your eye care professional. Other Risks of Contact Lenses Other risks of contact lenses include pink eye ( ...

  7. MISSING: BUBBLE CHAMBER LENS

    CERN Multimedia

    2001-01-01

    Would the person who borrowed the large bubble chamber lens from the Microcosm workshops on the ISR please return it. This is a much used piece from our object archives. If anybody has any information about the whereabouts of this object, please contact Emma.Sanders@cern.ch Thank you

  8. The Lens of Chemistry

    Science.gov (United States)

    Thalos, Mariam

    2013-01-01

    Chemistry possesses a distinctive theoretical lens--a distinctive set of theoretical concerns regarding the dynamics and transformations of a perplexing variety of organic and nonorganic substances--to which it must be faithful. Even if it is true that chemical facts bear a special (reductive) relationship to physical facts, nonetheless it will…

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... wear any kind of contact lens. In Butler's case, the lenses caused an infection and left her with a corneal ... A recent article from U.S. News and World Report explains what ophthalmologists are and how they can ...

  10. Quadrupole magnetic lens

    International Nuclear Information System (INIS)

    Piskunov, V.A.

    1981-01-01

    The following connection of windings of electromagnet is suggested for simplification of the design of qUadrupole magnetic lens intended for use in radiotechnical and electron-optical devices. The mentioned windings are connected with each other by a bridge scheme and the variable resistors are switched in its diagonals in the lens containing four electromagnet with windings connected with two variable resistors the mobile contacts of which are connected with a direct current source. Current redistribution between left windings and right windings takes place at shift of mobile contact of variable resistor, and current redistribution between upper and low coils of electromagnets takes place at shifting mobile contact of the other variable resistor. In this case smooth and independent electron-optical misalignment of lens by two mutually perpendicular directions proceeds. Use of the given design of the lens in the oscillograph permits to use printing assembly for alignment plate and to reduce the number of connections at the expense of decreasing the number of resistors

  11. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... can be purchased over-the-counter or on the Internet," says Thomas Steinemann, MD, professor of ophthalmology at ... ask for a prescription. There is no such thing as a "one size fits all" contact lens. Lenses that are not properly fitted may scratch the eye or cause blood vessels to grow into ...

  12. Vitreous changes after intravitreal bevacizumab monotherapy for retinopathy of prematurity: a case series.

    Science.gov (United States)

    Shoeibi, Nasser; Hosseini, Seyedeh Maryam; Banaee, Touka; Ansari-Astaneh, Mohammad-Reza; Abrishami, Majid; Ahmadieh, Hamid

    2018-01-01

    Reporting a special clinical finding after intravitreal bevacizumab monotherapy for retinopathy of prematurity. In a retrospective case series, the clinical courses of five premature infants with similar vitreous changes after a single dose of intravitreal bevacizumab (IVB) injection without additional laser therapy were reported. The mean post-conceptional age at IVB injection was 39.8 ± 2.2 (range 37-43) weeks. Localized vitreous syneresis and linear fibrotic vitreous condensation occurred 8.2 ± 2.3 weeks after IVB monotherapy in our patients (15.5% of injections). The mean last post injection visit was 61.6 ± 5.3 weeks (post-conceptional age). Further regression and complete retinal vascularization occurred in all patients. Thread-like vitreous condensation with localized vitreous liquefaction may be related to involutional ROP disease itself, combined to anti VEGF therapy and may be a predictor factor for further regression and retinal vascularization. The case series describes a successful response to anti-VEGF monotherapy with no further complications.

  13. [Research Progress of Vitreous Humor Detection Technique on Estimation of Postmortem Interval].

    Science.gov (United States)

    Duan, W C; Lan, L M; Guo, Y D; Zha, L; Yan, J; Ding, Y J; Cai, J F

    2018-02-01

    Estimation of postmortem interval (PMI) plays a crucial role in forensic study and identification work. Because of the unique anatomy location, vitreous humor is considered to be used for estima- ting PMI, which has aroused interest among scholars, and some researches have been carried out. The detection techniques of vitreous humor are constantly developed and improved which have been gradually applied in forensic science, meanwhile, the study of PMI estimation using vitreous humor is updated rapidly. This paper reviews various techniques and instruments applied to vitreous humor detection, such as ion selective electrode, capillary ion analysis, spectroscopy, chromatography, nano-sensing technology, automatic biochemical analyser, flow cytometer, etc., as well as the related research progress on PMI estimation in recent years. In order to provide a research direction for scholars and promote a more accurate and efficient application in PMI estimation by vitreous humor analysis, some inner problems are also analysed in this paper. Copyright© by the Editorial Department of Journal of Forensic Medicine.

  14. Occurrence and structural characterization of versican-like proteoglycan in human vitreous.

    Science.gov (United States)

    Theocharis, Achilleas D; Papageorgakopoulou, Nickoletta; Feretis, Elias; Theocharis, Dimitrios A

    2002-12-01

    Human vitreous gel is a special type of extracellular matrix, in which interpenetrating networks of collagen fibrils and hyaluronan are found. In this study, we report that apart from significant amounts of collagen, hyaluronan and sialylated glycoproteins, it was found that the human vitreous gel also contained low amounts of versican-like proteoglycan. The concentration of versican-like proteoglycan in the whole vitreous is 0.06 mg protein/ml of vitreous gel and represents a small percentage (about 5%) of the total protein content. The versican-like proteoglycan has a molecular mass of 380 kDa, as estimated by gel chromatography. Its core protein is substituted by chondroitin sulphate side chains (average molecular weight 37 kDa), in which 6-sulphated disaccharides predominated. According to the physicochemical data, the number of chondroitin sulphate chains is likely to be 5-7 per molecule. These proteoglycan monomers form large aggregates with endogenous hyaluronan. Versican, which is able to bind lectins via its C-terminal region, may bridge or interconnect various constituents of the extracellular matrix via its terminal domains in order to stabilize large supramolecular complexes at the vitreous, contributing towards the integrity and specific properties of the tissue.

  15. Pathological findings in the lens capsules and intraocular lens in chronic pseudophakic endophthalmitis: an electron microscopy study.

    Science.gov (United States)

    Adán, A; Casaroli-Marano, R P; Gris, O; Navarro, R; Bitrian, E; Pelegrin, L; Sanchez-Dalmau, B

    2008-01-01

    The aim of this study was to describe the pathological findings in lens capsules and intraocular lens (IOL) studied by scanning and/or transmission electron microscopy (SEM and TEM, respectively) in a series of four eyes with chronic pseudophakic endophthalmitis (CPE). We performed a retrospective study of four patients presenting CPE in whom surgical treatment with pars plana vitrectomy, capsulectomy with extraction of the IOL, and intravitreous antibiotic therapy was thereafter performed. The extracted IOL and the capsular remains were studied by SEM and/or TEM and microbiologic analysis of aqueous humour and vitreous aspirate was also carried out in all the cases. The presence of microorganisms was observed in the material analysed in all the cases studied. The use of TEM identified bacterial contamination by Staphylococcus spp and mixed contamination with microorganisms presenting a bacillar morphology suggestive of infection by Propionibacterium acnes in addition to the presence of cocci in the capsular remains. In another two cases, SEM localized colonies of Staphylococcus spp on the surface of the IOL in one case and mixed bacterial colonization with cocci plus filamentous bacteria in the other. The presence of macrophages associated with bacteria was observed in the capsular remains. Microorganisms were found in the IOL or the capsular material in the four cases studied, thereby explaining the refractoriness and severity of infection. The possible presence of polymicrobial infections, especially in the cases with filamentous bacteria, also explains the recurrence of infection.

  16. Detection of Glutamate and γ-aminobutyric Acid in Vitreous of Patients with Proliferative Diabetic Retinopathy

    Institute of Scientific and Technical Information of China (English)

    Juan Deng; De-Zheng Wu; Rulong Gao

    2000-01-01

    Purpose: To study the levels of glutamate and γ-aminobutyric acid (GABA) in vitreous of patients with proliferative diabetic retinopathy(PDR) and to investigate their roles in retinal ischemia.Method: Vitreous samples were collected from 25 patients (27 eyes) with PDR and 14patients ( 14 eyes) with idiopathic macular hole. Glutamate and GABA detection were performed by high-performance liquid chromatography (HPLC).Results: Patients with PDR had significantly higher concentrations of glutamate and GABA than the control group. The glutamate level has a significantly positive correlation with GABA level.Conclusion: Detection of glutamate and GABA in vitreous provides biochemical support for the mechanism and treatment of ischemic retinal damage in patients with PDR.

  17. Proteomic analysis of the vitreous following experimental retinal detachment in rabbits

    DEFF Research Database (Denmark)

    Mandal, Nakul; Lewis, Geoffrey P.; Fisher, Steven K.

    2015-01-01

    of the vitreous following experimental retinal detachment using a comparative proteomic based approach. Materials and Methods. Retinal detachment was created in the right eyes of six New Zealand red pigmented rabbits. Sham surgery was undertaken in five other rabbits that were used as controls. After seven days......Purpose. The pathogenesis of rhegmatogenous retinal detachment (RRD) remains incompletely understood, with no clinically effective treatment for potentially severe complications such as photoreceptor cell death and proliferative vitreoretinopathy. Here we investigate the protein profile...... the eyes were enucleated and the vitreous was removed. The vitreous samples were evaluated with two-dimensional polyacrylamide gel electrophoresis and the differentially expressed proteins were identified with tandem mass spectrometry. Results. Ten protein spots were found to be at least twofold...

  18. Genetic analysis of vitreous endosperms derived from homozygotic plants for opaque-2 gene in maize (Zea mays L.)

    International Nuclear Information System (INIS)

    Prioli, A.J.; Barbosa, H.M.; Sant'Anna, R.

    1980-01-01

    From experiments in which opaque-2 maize seeds were treated with gamma rays and ethil methanesulfonate, and their respective untreated controls, seeds with hard, vitreous endosperms were obtained. Some of these were completely vitreous, with no evidence of opaque endosperm tissue. Others had very small and few (one to three) areas of opaque tissue. Plants derived from completely vitreous endosperm seeds were self pollinated and crossed to an opaque-2 inbred. The segregation of vitreous to opaque seeds indicated that the normal allele at the opaque-2 locus was responsible for the vitreousity of the endosperm. Lysine content of the vitreous endosperm was comparable to that of normal endosperms. Plants derived from vitreous seeds with few and tiny spots of opaque tissue produced, upon selfing or crossing to the opaque-2 inbred, only opaque-2 seeds. It is concluded that: (a) induced mutation may not be an effective tool to obtain vitreous opaque-2 endosperm with high lysine content; and, (b) there are unknown genetic systems which severely modify the expression of the opaque-2 gene. (Author) [pt

  19. Posterior vitreous detachment - prevalence of and risk factors for retinal tears

    Directory of Open Access Journals (Sweden)

    Bond-Taylor M

    2017-09-01

    Full Text Available Martin Bond-Taylor,1 Gunnar Jakobsson,1,2 Madeleine Zetterberg1,2 1Department of Ophthalmology, Sahlgrenska University Hospital, Mölndal, 2Department of Clinical Neuroscience/Ophthalmology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden Purpose: The present study aimed to describe clinical characteristics of patients with posterior vitreous detachment (PVD, to determine the prevalence of retinal tears in PVD patients, and to find predictors for retinal tears in this patient group. Methods: Retrospective analysis of medical records on patients diagnosed with PVD, retinal tears, or vitreous hemorrhage at the Department of Ophthalmology at Sahlgrenska University Hospital, a tertiary eye center. Results: Between February and July 2009, 365 patients consulted the Department of Ophthalmology for PVD-related symptoms. The incidence of retinal tears was 14.5% (n=53 and that of vitreous and/or retinal hemorrhage was 22.7% (n=83. For analysis of possible predictors for complications to PVD, patients diagnosed with retinal tears or vitreous hemorrhage between May and July 2009 were also included in the study, resulting in a total of 426 patients. Predictors of a retinal tear were symptoms of visual impairment (P=0.024, the presence of vitreous or retinal hemorrhage at examination (P<0.001, and a duration of symptoms for <24 hours (P=0.004. Symptoms of flashes did not constitute an extra risk of retinal tears (P=0.135. Subsequent retinal pathology (follow-up time 4.5 years, including vitreous detachment/hemorrhage or retinal tears/detachment, occurred more often in patients presenting with a retinal tear. For patients with a retinal tear, the relative risk of having a retinal detachment in the same eye during the follow-up time was 17.7 when compared to patients without a retinal tear (risk ratio 17.7, 95% confidence interval 2.2–145. Conclusion: Patients seeking care on the first day have a

  20. Application and development of non contact angle-wide viewing system in vitreous retinal surgery

    Directory of Open Access Journals (Sweden)

    Rong-Hua He

    2016-07-01

    Full Text Available Wide-angle viewing system as an important auxiliary device can clearly observe the whole fundus field of vision in vitreous surgery, which enable vitreoretinal surgery more efficient, safer and more effective. So it has very high application value in ophthalmologic operation. In this paper, we studied the development and application of wide-angle viewing system in vitreoretinal surgery in recent years, from which we summed up the advantage of non-contact wide-angle viewing system in clinical field, and pointed out the shortcomings. The ultimate goal is to make the non-contact wide-angle viewing system better applied in vitreous surgery.

  1. Integrating Micro- or Nanoscale Encapsulation Technology with Vitreous Cryopreservation: A New Strategy to Improve Biopreservation.

    Science.gov (United States)

    Zheng, Y Y; Zhao, G

      BACKGROUND: None-uniform distributions of temperatures, limited freezing and thawing rates, and thermal stresses are three main hindering factors for successful vitreous cryopreservation of mass volume of biosamples. Micro- and nanoscale encapsulation, owning the intrinsic features to avoid those limitations introduced by the traditional approaches, has been opened up a new way for effective and high-efficiency biopreservation. This short review article summarizes recent advances in cell encapsulation technology for biopreservation by manipulating cells and biological agents in micro- or nanoscale volume droplets and microgels, and discusses its promising applications for future vitreous cryopreservation.

  2. Vitreous-induced cytoskeletal rearrangements via the Rac1 GTPase-dependent signaling pathway in human retinal pigment epithelial cells

    International Nuclear Information System (INIS)

    Huang, Xionggao; Wei, Yantao; Ma, Haizhi; Zhang, Shaochong

    2012-01-01

    Highlights: ► Vitreous induces morphological changes and cytoskeletal rearrangements in RPE cells. ► Rac1 is activated in vitreous-transformed RPE cells. ► Rac inhibition prevents morphological changes in vitreous-transformed RPE cells. ► Rac inhibition suppresses cytoskeletal rearrangements in vitreous-transformed RPE cells. ► The vitreous-induced effects are mediated by a Rac1 GTPase/LIMK1/cofilin pathway. -- Abstract: Proliferative vitreoretinopathy (PVR) is mainly caused by retinal pigment epithelial (RPE) cell migration, invasion, proliferation and transformation into fibroblast-like cells that produce the extracellular matrix (ECM). The vitreous humor is known to play an important role in PVR. An epithelial-to-mesenchymal transdifferentiation (EMT) of human RPE cells induced by 25% vitreous treatment has been linked to stimulation of the mesenchymal phenotype, migration and invasion. Here, we characterized the effects of the vitreous on the cell morphology and cytoskeleton in human RPE cells. The signaling pathway that mediates these effects was investigated. Serum-starved RPE cells were incubated with 25% vitreous, and the morphological changes were examined by phase-contrast microscopy. Filamentous actin (F-actin) was examined by immunofluorescence and confocal microscopy. Protein phosphorylation of AKT, ERK1/2, Smad2/3, LIM kinase (LIMK) 1 and cofilin was analyzed by Western blot analysis. Vitreous treatment induced cytoskeletal rearrangements, activated Rac1 and enhanced the phosphorylation of AKT, ERK1/2 and Smad2/3. When the cells were treated with a Rac activation-specific inhibitor, the cytoskeletal rearrangements were prevented, and the phosphorylation of Smad2/3 was blocked. Vitreous treatment also enhanced the phosphorylation of LIMK1 and cofilin and the Rac inhibitor blocked this effect. We propose that vitreous-transformed human RPE cells undergo cytoskeletal rearrangements via Rac1 GTPase-dependent pathways that modulate LIMK1 and

  3. Vitreous-induced cytoskeletal rearrangements via the Rac1 GTPase-dependent signaling pathway in human retinal pigment epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xionggao [State Key Ophthalmic Laboratory, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou (China); Department of Ophthalmology, Hainan Medical College, Haikou (China); Wei, Yantao; Ma, Haizhi [State Key Ophthalmic Laboratory, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou (China); Zhang, Shaochong, E-mail: zhshaochong@163.com [State Key Ophthalmic Laboratory, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou (China)

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer Vitreous induces morphological changes and cytoskeletal rearrangements in RPE cells. Black-Right-Pointing-Pointer Rac1 is activated in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition prevents morphological changes in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer Rac inhibition suppresses cytoskeletal rearrangements in vitreous-transformed RPE cells. Black-Right-Pointing-Pointer The vitreous-induced effects are mediated by a Rac1 GTPase/LIMK1/cofilin pathway. -- Abstract: Proliferative vitreoretinopathy (PVR) is mainly caused by retinal pigment epithelial (RPE) cell migration, invasion, proliferation and transformation into fibroblast-like cells that produce the extracellular matrix (ECM). The vitreous humor is known to play an important role in PVR. An epithelial-to-mesenchymal transdifferentiation (EMT) of human RPE cells induced by 25% vitreous treatment has been linked to stimulation of the mesenchymal phenotype, migration and invasion. Here, we characterized the effects of the vitreous on the cell morphology and cytoskeleton in human RPE cells. The signaling pathway that mediates these effects was investigated. Serum-starved RPE cells were incubated with 25% vitreous, and the morphological changes were examined by phase-contrast microscopy. Filamentous actin (F-actin) was examined by immunofluorescence and confocal microscopy. Protein phosphorylation of AKT, ERK1/2, Smad2/3, LIM kinase (LIMK) 1 and cofilin was analyzed by Western blot analysis. Vitreous treatment induced cytoskeletal rearrangements, activated Rac1 and enhanced the phosphorylation of AKT, ERK1/2 and Smad2/3. When the cells were treated with a Rac activation-specific inhibitor, the cytoskeletal rearrangements were prevented, and the phosphorylation of Smad2/3 was blocked. Vitreous treatment also enhanced the phosphorylation of LIMK1 and cofilin and the Rac inhibitor blocked this effect. We propose that vitreous

  4. Development of a Fresnel lens for cold neutrons based on neutron refractive optics

    CERN Document Server

    Oku, T; Moriyasu, S; Yamagata, Y; Ohmori, H; Takizawa, Y; Shimizu, H M; Hirota, T; Kiyanagi, Y; Ino, T; Furusaka, M; Suzuki, J

    2001-01-01

    We have developed compound refractive lenses (CRLs) for cold neutrons, which are made of vitreous silica and have an effective potential of (90.1-2.7x10 sup - sup 4 i) neV. In the case of compound refractive optics, neutron absorption by the material deteriorates lens performance. Thus, to prevent an increase in neutron absorption with increasing beam size, we have developed Fresnel lenses using the electrolytic in-process dressing grinding technique. The lens characteristics were carefully investigated with experimental and numerical simulation studies. The lenses functioned as a neutron focusing lens, and the focal length of 14 m was obtained with a 44-element series of the Fresnel lenses for 10 A neutrons. Moreover, good neutron transmission of 0.65 for 15 A neutrons was obtained due to the shape effect. According to comprehensive analysis of the obtained results, it is possible to realize a CRL for practical use by choosing a suitable lens shape and material.

  5. A Correlation of Thin Lens Approximation to Thick Lens Design by Using Coddington Factors in Lens Design and Manufacturing

    OpenAIRE

    FARSAKOĞLU, Ö. Faruk

    2014-01-01

    The effect of Coddington factors on aberration functions has been analysed using thin lens approximation. Minimizing spherical aberrations of singlet lenses using Coddington factors in lens design depending on lens manufacturing is discussed. Notation of lens test plate pairs used in lens manufacturing is also presented in terms of Coddington shape factors.

  6. Dose limits to the eye lens

    International Nuclear Information System (INIS)

    Sion, N.

    2016-01-01

    Protecting the human body from the effects of ionizing radiation is essential to forestall stochastic effects and require placing limits on the effective dose. Dose limits on specific organs are also necessary to reduce the deterministic effects and tissue reactions. The standard for radiation protection was ISO 15382 (2002) which mainly dealt with beta radiation for nuclear power plant workers. Clearly an update is required to allow for new technology and the proliferative use of radiation in medical practices. There is a need for more explicit radiation monitoring to operators and staff. ICRP118 (International Commission on Radiological Protection), Ref. 1, evolved their recommendations to include eye lens doses as a follow on to their publication 103 and to focus on radiation exposures. It provides updated estimates of 'practical' threshold doses for tissue injury at the level of 1% incidence. This paper discusses the current status and the recommendation for a drastic reduction of the dose limit to the eye lens. (author)

  7. Lens subluxation grading system: predictive value for ectopia lentis surgical outcomes

    Directory of Open Access Journals (Sweden)

    Mauro Waiswol

    2009-03-01

    Full Text Available Objective: To present a classification system to grade ectopia lentis and to assess its usefulness as a predictor for surgical outcomes. Methods: Fifty-one eyes of 28 patients with either simple (19 patients or Marfan syndrome-associated ectopia lentis (nine patients with variable degrees of subluxation were operated on. Lens subluxation intensity was graded according to the lens subluxation grading system (LSGS from grade 1 (lens on the whole pupillary area up to grade 4 (lens absent from the pupillary area. Thirty eyes underwent cataract extraction (“dry” aspiration with endocapsular ring and in-the-bag intraocular lens (IOL implantation. Twenty-one eyes underwent cataract extraction (“dry” aspiration with scleral fixation of the IOL. The predictive value of the LSGS was assessed by analyzing the post-operative outcomes, including visual acuity (VA, endothelial cell loss, and complications for each grade on the grading system. Rresults: Patients were classified into grade 1 (19.6%, grade 2 (51% and grade 3 (29.4%. Post-operative VA was lower for eyes with larger degrees of subluxation. The higher the subluxation grade, the higher the endothelial cell loss, as well as, the frequency of vitreous loss and surgical time. Higher subluxation grades prevented optimal surgical outcomes with endocapsular ring and in-the-bag IOL implantation. Cconclusions: The LSGS provides an estimate of the surgical success of ectopia lentis. Adequate standardization of lens subluxation is crucial for understanding studies dealing with the surgical correction of this disorder.

  8. Pars plana vitrectomy for disturbing primary vitreous floaters: clinical outcome and patient satisfaction

    NARCIS (Netherlands)

    Nie, K.F. de; Crama, N.; Tilanus, M.A.D.; Klevering, B.J.; Boon, C.J.F.

    2013-01-01

    BACKGROUND: Primary vitreous floaters can be highly bothersome in some patients. In the case of persistently bothersome floaters, pars plana vitrectomy may be the most effective treatment. The aim of this study is to evaluate the incidence of complications, and patient satisfaction, after pars plana

  9. Characterization of a Stabilized Form of Microplasmin for the Induction of Posterior Vitreous Detachment

    NARCIS (Netherlands)

    Gad Elkareem, Ashraf M.; Willekens, Ben; Vanhove, Marc; Noppen, Bernard; Stassen, Jean Marie; de Smet, Marc D.

    2010-01-01

    Purpose: To investigate the stability and safety of a diluted acidified form of microplasmin and its ability to induce a posterior vitreous detachment (PVD) following intravitreal injection in postmortem porcine eyes. Methods: Microplasmin diluted in normal saline (NS) and balanced salt solution

  10. Coordination defects in vitreous As2S3 induced by γ-irradiation

    International Nuclear Information System (INIS)

    Shpotyuk, O.; Balitska, V.

    1997-01-01

    Destruction-polymerization transformations in vitreous As 2 S 3 , associated with coordination defects formation process induced by γ-irradiation, were studied by the IR Fourier Spectroscopy method in the region of 400-100 cm -1 . All topological variants of these processes, statistically possible in the investigated samples, were taken into account for physical consideration of the real structural changes. (author)

  11. iTRAQ Quantitative Proteomic Analysis of Vitreous from Patients with Retinal Detachment

    Directory of Open Access Journals (Sweden)

    Fátima Milhano Santos

    2018-04-01

    Full Text Available Rhegmatogenous retinal detachment (RRD is a potentially blinding condition characterized by a physical separation between neurosensory retina and retinal pigment epithelium. Quantitative proteomics can help to understand the changes that occur at the cellular level during RRD, providing additional information about the molecular mechanisms underlying its pathogenesis. In the present study, iTRAQ labeling was combined with two-dimensional LC-ESI-MS/MS to find expression changes in the proteome of vitreous from patients with RRD when compared to control samples. A total of 150 proteins were found differentially expressed in the vitreous of patients with RRD, including 96 overexpressed and 54 underexpressed. Several overexpressed proteins, several such as glycolytic enzymes (fructose-bisphosphate aldolase A, gamma-enolase, and phosphoglycerate kinase 1, glucose transporters (GLUT-1, growth factors (metalloproteinase inhibitor 1, and serine protease inhibitors (plasminogen activator inhibitor 1 are regulated by HIF-1, which suggests that HIF-1 signaling pathway can be triggered in response to RRD. Also, the accumulation of photoreceptor proteins, including phosducin, rhodopsin, and s-arrestin, and vimentin in vitreous may indicate that photoreceptor degeneration occurs in RRD. Also, the accumulation of photoreceptor proteins, including phosducin, rhodopsin, and s-arrestin, and vimentin in vitreous may indicate that photoreceptor degeneration occurs in RRD. Nevertheless, the differentially expressed proteins found in this study suggest that different mechanisms are activated after RRD to promote the survival of retinal cells through complex cellular responses.

  12. The rabbit as an animal model for post-natal vitreous matrix differentiation and degeneration

    NARCIS (Netherlands)

    Los, L. I.

    2008-01-01

    Purpose This study evaluates whether rabbits are a suitable animal model to study post-natal vitreous differentiation and degeneration. Methods Human and rabbit eyes of various ages were studied by complementary anatomical techniques, light microscopy, and transmission electron microscopy. Results

  13. Blood culture bottles are superior to conventional media for vitreous culture.

    Science.gov (United States)

    Thariya, Patsuda; Yospaiboon, Yosanan; Sinawat, Suthasinee; Sanguansak, Thuss; Bhoomibunchoo, Chavakij; Laovirojjanakul, Wipada

    2016-08-01

    To compare blood culture bottles and conventional media for the vitreous culture in patients with clinically suspected infectious endophthalmitis. Retrospective comparative study at KKU Eye Center, Khon Kaen University. There were 342 patients with clinically suspected infectious endophthalmitis participated in the study. The vitreous specimens were inoculated in both blood culture bottles and on conventional culture media (blood agar, MacConkey agar, chocolate agar, Sabouraud dextrose agar and thioglycolate broth). The number of positive culture yields in both blood culture bottles and conventional media. Positive culture yields in both methods were found in 151 eyes (49.5%). There were 136 of 151 eyes (90.1%) with positive culture in blood culture bottles, whereas 99 of 151 eyes (65.6%) yielded positive cultures in conventional media. These findings were different with a statistical significance (P culture bottles and conventional media improved the yield. Blood culture bottles are superior to conventional media for vitreous culture in clinically suspected infectious endophthalmitis. Vitreous culture using blood culture bottles should be recommended as the primary method for microbiological diagnosis. A combination of both methods further improves the positive culture yield. © 2016 Royal Australian and New Zealand College of Ophthalmologists.

  14. Proliferative and inflammatory factors in the vitreous of patients with proliferative diabetic retinopathy

    Directory of Open Access Journals (Sweden)

    V V Chernykh

    2015-01-01

    Full Text Available Purpose: The purpose was to measure the concentrations of various cytokines and growth factors (including vascular endothelial growth factor [VEGF] and pigment epithelium-derived factor [PEDF] in the vitreous of patients with proliferative diabetic retinopathy (PDR and to investigate interaction between inflammatory and proliferative factors in the genesis of PDR. Materials and Methods : Vitreous samples from 32 eyes with PDR and 25 eyes without diabetes mellitus and signs of DR (control were collected. Vitreous concentrations of VEGF, PEDF, monocyte chemotactic protein-1 (MCP-1, interleukin-4 (IL-4, IL-6, IL-8, IL-10, IL-17A, and secretory immunoglobulin A (sIgA were simultaneously measured using enzyme-linked immunoassay. Results : Vitreous levels of VEGF, PEDF, IL-17A, IL-6, IL-8, IL-4, and sIgA were significantly (Π < 0.05 higher in eyes with PDR compared to control. The concentration of VEGF was more than 17-times higher than in control, and the concentration of PEDF was not changed oppositely and was also higher (1.45-times compared to control, that may indicate disturbances of compensatory mechanisms in angiogenesis regulation in PDR. Significant (Π < 0.05 positive correlations were observed between vitreous concentrations of VEGF and IL-17ΐ (r = 0.45, VEGF and IL-8 (r = 0.48, VEGF and IL-4 (r = 0.51, PEDF and IL-17ΐ (r = 0.48, PEDF and IL-8 (r = 0.59, MCP-1 and PEDF (r = 0.72, MCP-1 and IL-8 (r0 = 0.45, IL-4 and IL-17ΐ (r = 0.65, IL-4 and IL-8 (r = 0.71, IL-8 and IL-17ΐ (r = 0.59. Conclusions: Significantly raised levels of inflammatory and proliferative factors and numerous positive correlations between them may demonstrate a significant role of activation of vascular proliferation and local inflammation in the pathogenesis of PDR.

  15. Partial characterization of a putative new growth factor present in pathological human vitreous.

    Science.gov (United States)

    Pombo, C; Bokser, L; Casabiell, X; Zugaza, J; Capeans, M; Salorio, M; Casanueva, F

    1996-03-01

    Several growth factors have been implicated in the development of proliferative eye diseases, and some of those are present in human vitreous (HV). The effects of HV on cellular responses which modulate proliferative cell processes were studied. This study describes the partial characterization of a vitreous factor activity which does not correspond to any of the previously reported growth factors in pathological HV. Vitreous humour was obtained from medical vitrectomies, from patients with PDR and PVR. The biological activity of the vitreous factor was determined by its ability to increase cytosolic calcium concentration ([Ca2+]i), increase production of inositol phosphates, and induce cell proliferation in the cell line EGFR T17. In some experiments other cell lines, such as NIH 3T3, 3T3-L1, FRTL5, A431, PC12, Y79, and GH3, were also employed. Measurement of [Ca2+]i in cell suspensions was performed using the fluorescent Ca2+ indicator fura-2. The activity of the factor present in HV was compared with other growth factors by means of: (a) [Ca2+]i mobilization pattern, (b) sequential homologous and heterologous desensitization of receptors, (c) effects of phorbol esters on their action, and (d) inactivation after treatment with different proteolytic enzymes. The HV-induced cell proliferation and increases in [Ca2+]i concentration were characterized by a peculiar time pattern. The different approaches used ruled out its identity with PDGF, bFGF, EGF, TGF-beta, IGFs, TNF-alpha, NGF, and other compounds such as ATP, angiotensin I, and bradykinin. Vitreous factor actions are mediated by specific receptors apparently regulated by PKC. This factor is able to induce [Ca2+]i mobilization in most of the cell lines studied, indicating that its effects are not tissue specific. These results suggest the presence of a growth factor activity in pathological HV which may be due to the presence of an undescribed growth factor in the eye.

  16. CD18 expression in granulocytes infiltrating the vitreous fluid in patients with diabetic retinopathy

    Institute of Scientific and Technical Information of China (English)

    Qi; Zhu; Hu-Ping; Song

    2015-01-01

    AIM: To assess the levels of CD18 on the surface of granulocytes infiltrating the vitreous fluid in patients with diabetic retinopathy(DR).METHODS: Vitreous samples from twelve patients with non-proliferative DR with significant macula edema(group A), 33 patients with proliferative DR(grade 3 as group B, n =14, and, grade 4 as group C, n =19) were obtained during pars plana vitrectomy. Vitreous samples from 12 patients with macular hole as controls(group D)were analyzed together. The infiltrating of granulocytes and its surface level of CD18 were measured by flow cytometry. The level of CD18 was presented as the mean channel fluorescence(MCF) on a logarithmic scale. RESULTS: Granulocytes were detected in 6 of 12 vitreous samples from group A, 9 of 14 from group B, 15 of 19 from group C, and none of 12 from group D. MCF of CD18 on granulocytes from groups A, B, and C were2.978 ±1.446, 3.201 ±0.692, and 4.072 ±0.837, respectively.The difference was significant(F =4.354, P =0.021).Subjects with more severe DR were more likely to have a higher level of CD18 MCF(trend test, 掊2=7.351, P =0.007).CD18 MCF was significantly associated with the development of DR(r =0.46, P =0.005 and β =0.147, P =0.035).CONCLUSION: Our results confirm the presence of granulocytes and the elevated levels of CD18 on the surface of them in the vitreous fluid from DR patients.These results may provide indirect evidence shown that granulocytes activation also has occurred in the retinal local compared to non-DR control.

  17. Characteristics of the thick, compound refractive lens

    International Nuclear Information System (INIS)

    Pantell, Richard H.; Feinstein, Joseph; Beguiristain, H. Raul; Piestrup, Melvin A.; Gary, Charles K.; Cremer, Jay T.

    2003-01-01

    A compound refractive lens (CRL), consisting of a series of N closely spaced lens elements each of which contributes a small fraction of the total focusing, can be used to focus x rays or neutrons. The thickness of a CRL can be comparable to its focal length, whereupon a thick-lens analysis must be performed. In contrast with the conventional optical lens, where the ray inside the lens follows a straight line, the ray inside the CRL is continually changing direction because of the multiple refracting surfaces. Thus the matrix representation for the thick CRL is quite different from that for the thick optical lens. Principal planes can be defined such that the thick-lens matrix can be converted to that of a thin lens. For a thick lens the focal length is greater than for a thin lens with the same lens curvature, but this lengthening effect is less for the CRL than for the conventional optical lens

  18. Elevated Levels of Cytokines Associated with Th2 and Th17 Cells in Vitreous Fluid of Proliferative Diabetic Retinopathy Patients.

    Directory of Open Access Journals (Sweden)

    Masaru Takeuchi

    Full Text Available Macrophages are involved in low-grade inflammation in diabetes, and play pathogenic roles in proliferative diabetic retinopathy (PDR by producing proinflammatory cytokines. T cells as well as other cells are also activated by proinflammatory cytokines, and infiltration into the vitreous of patients with PDR has been shown. In this study, we measured helper T (Th cell-related cytokines in the vitreous of PDR patients to define the characteristics of Th-mediated immune responses associated with PDR. The study group consisted of 25 type 2 diabetic patients (25 eyes with PDR. The control group consisted of 27 patients with epiretinal membrane (ERM, 26 patients with idiopathic macular hole (MH, and 26 patients with uveitis associated with sarcoidosis. Vitreous fluid was obtained at the beginning of vitrectomy, and centrifuging for cellular removals was not performed. Serum was also collected from PDR patients. IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, soluble sCD40L, and TNFα in the vitreous and serum samples were measured. Both percent detectable and levels of IL-4, IL-6, IL-17A, IL-21, IL-22, and TNFα in the vitreous were significantly higher than those in the serum in PDR patients. Vitreous levels of these cytokines and IL-31 were significantly higher in PDR than in ERM or MH patients. Vitreous levels of IL-4, IL-17A, IL-22, IL-31, and TNFα in PDR patients were also significantly higher than those of sarcoidosis patients. In PDR patients, vitreous IL-17A level correlated significantly with vitreous levels of IL-22 and IL-31, and especially with IL-4 and TNFα. Although it is unclear whether these cytokines play facilitative roles or inhibitory roles for the progression of PDR, the present study indicated that Th2- and Th17-related immune responses are involved in the pathogenesis of PDR.

  19. Eye lens radiation exposure in Greek interventional cardiology personnel

    International Nuclear Information System (INIS)

    Thrapsanioti, Zoi; Askounis, Panagiotis; Carinou, Eleftheria; Datseris, Ioannis; Diamanti, Ramza Anastasia; Papathanasiou, Miltiadis

    2017-01-01

    The lens of the eye is one of the radiosensitive tissues of the human body; if exposed to ionizing radiation can develop radiation-induced cataract at early ages. This study was held in Greece and included 44 Interventional Cardiologists (ICs) and an unexposed to radiation control group of 22 persons. Of the note, 26 ICs and the unexposed individuals underwent special eye examinations. The detected lens opacities were classified according to LOCS III protocol. Additionally, the lens doses of the ICs were measured using eye lens dosemeters. The mean dose to the lenses of the ICs per month was 0.83 ± 0.59 mSv for the left and 0.35 ± 0.38 mSv for the right eye, while the annual doses ranged between 0.7 and 11 mSv. Regarding the lens opacities, the two groups did not differ significantly in the prevalence of either nuclear or cortical lens opacities, whereas four ICs were detected with early stage subcapsular sclerosis. Though no statistically difference was observed in the cohort, the measured doses indicate that the eye doses received from the ICs can be significant. To minimize the radiation-induced risk at the eye lenses, the use of protective equipment and appropriate training on this issue is highly recommended. (authors)

  20. Assessment of eye lens doses for workers during interventional radiology procedures

    International Nuclear Information System (INIS)

    Urboniene, A.; Sadzeviciene, E.; Ziliukas, J.

    2015-01-01

    The assessment of eye lens doses for workers during interventional radiology (IR) procedures was performed using a new eye lens dosemeter. In parallel, the results of routine individual monitoring were analysed and compared with the results obtained from measurements with a new eye lens dosemeter. The eye lens doses were assessed using H p (3) measured at the level of the eyes and were compared with H p (10) measured with the whole-body dosemeter above the lead collar. The information about use of protective measures, the number of performed interventional procedures per month and their fluoroscopy time was also collected. The assessment of doses to the lens of the eye was done for 50 IR workers at 9 Lithuanian hospitals for the period of 2012-2013. If the use of lead glasses is not taken into account, the estimated maximum annual dose equivalent to the lens of the eye was 82 mSv. (authors)

  1. Multiple methods of surgical treatment combined with primary IOL implantation on traumatic lens subluxation/dislocation in patients with secondary glaucoma.

    Science.gov (United States)

    Wang, Rui; Bi, Chun-Chao; Lei, Chun-Ling; Sun, Wen-Tao; Wang, Shan-Shan; Dong, Xiao-Juan

    2014-01-01

    To describe clinical findings and complications from cases of traumatic lens subluxation/dislocation in patients with secondary glaucoma, and discuss the multiple treating methods of operation combined with primary intraocular lens (IOL) implantation. Non-comparative retrospective observational case series. 30 cases (30 eyes) of lens subluxation/dislocation in patients with secondary glaucoma were investigated which accepted the surgical treatment by author in the Ophthalmology of Xi'an No.4 Hospital from 2007 to 2011. According to the different situations of lens subluxation/dislocation, various surgical procedures were performed such as crystalline lens phacoemulsification, crystalline lens phacoemulsification combined anterior vitrectomy, intracapsular cataract extraction combined anterior vitrectomy, lensectomy combined anterior vitrectomy though peripheral transparent cornea incision, pars plana lensectomy combined pars plana vitrectomy, and intravitreal cavity crystalline lens phacofragmentation combined pars plana vitrectomy. And whether to implement trabeculectomy depended on the different situations of secondary glaucoma. The posterior chamber intraocular lenses (PC-IOLs) were implanted in the capsular-bag or trassclerally sutured in the sulus decided by whether the capsular were present. visual acuity, intraocular pressure, the situation of intraocular lens and complications after the operations. The follow-up time was 11-36mo (21.4±7.13). Postoperative visual acuity of all eyes were improved; 28 cases maintained IOP below 21 mm Hg; 2 cases had slightly IOL subluxation, 4 cases had slightly tilted lens optical area; 1 case had postoperative choroidal detachment; 4 cases had postoperative corneal edema more than 1wk, but eventually recovered transparent; 2 cases had mild postoperative vitreous hemorrhage, and absorbed 4wk later. There was no postoperative retinal detachment, IOL dislocation, and endophthalmitis. To take early treatment of traumatic lens

  2. [Application of Mixed-effect Model in PMI Estimation by Vitreous Humor].

    Science.gov (United States)

    Yang, M Z; Li, H J; Zhang, T Y; Ding, Z J; Wu, S F; Qiu, X G; Liu, Q

    2018-02-01

    To test the changes of the potassium (K⁺) and magnesium (Mg²⁺) concentrations in vitreous humor of rabbits along with postmortem interval (PMI) under different temperatures, and explore the feasibility of PMI estimation using mixed-effect model. After sacrifice, rabbit carcasses were preserved at 5 ℃, 15 ℃, 25 ℃ and 35 ℃, and 80-100 μL of vitreous humor was collected by the double-eye alternating micro-sampling method at every 12 h. The concentrations of K⁺ and Mg²⁺ in vitreous humor were measured by a biochemical-immune analyser. The mixed-effect model was used to perform analysis and fitting, and established the equations for PMI estimation. The data detected from the samples that were stoned at 10 ℃, 20 ℃ and 30 ℃ with 20, 40 and 65 h were used to validate the equations of PMI estimation. The concentrations of K⁺ and Mg²⁺ [f( x , y )] in vitreous humor of rabbits under different temperature increased along with PMI ( x ). The relative equations of K⁺ and Mg²⁺ concentration with PMI and temperature under 5 ℃~35 ℃ were f K⁺ ( x , y )=3.413 0+0.309 2 x +0.337 6 y +0.010 83 xy -0.002 47 x ² ( P PMI estimation by K⁺ and Mg²⁺ was in 10 h when PMI was between 0 to 40 h, and the time of deviation was in 21 h when PMI was between 40 to 65 h. the ambient temperature range of 5 ℃-35 ℃, the mixed-effect model based on temperature and vitreous humor substance concentrations can provide a new method for the practical application of vitreous humor chemicals for PMI estimation. Copyright© by the Editorial Department of Journal of Forensic Medicine.

  3. Ultrasound monitoring of vitreous in pre and postLasik patients

    Directory of Open Access Journals (Sweden)

    Amanda Alvarado, MD

    2003-12-01

    Full Text Available Title: Echografic Vitreoretinal Findings afterLaser In Situ Keratomileusis.Objective: To report the echographic changesobserved in the vitreous of patients followingLasik. Design: Prospective, observational,descriptive study. Method: We performed anultrasound of the vitreous of patients elegiblefor refractive surgery. Vitreous Changes weremeasured by video B scan ultrasonographybefore and at the first and third month after Lasikat Fundación Oftalmológica Nacional betweenJune 2002 and March 2003. Results: A total of16 patients, 67% women, 33% men, mean ageof 31.6 years (range between 22 and 40 years.A total of 29 eyes were studied, 16 right and 13left for a total of 87 echographies. The refractiveerrors in a range of -10.50 and +3.50 of sphericalequivalent. There were 24 myopic and 5hypermetropic eyes. The vitreous changes correspondedto a posterior vitreous detachment(PVD and the presence of opacities in thevitreous. At the beginning of the study 18 eyes(62% had evidenced PVD and all of the 29 eyes(100% had opacities; At the end of the controls changes were evidenced in 22 eyes (81%, thevitreous opacities increased in 14 eyes (48.27%,while they remained without changes in 15 eyes(51.7%. The presence of newly developed PVDwas documented in 10 eyes (30 %, there was anincrease of PVD in 8 eyes (27.5%, and in onecase we observed the presence of a traction areaat the vitreoretinal interfase that correspondedto 3.4% of the eyes studied; it was an hypermetropicpatient in whom ophthalmoscopically,after the echographic findings, we evidenced twooperculated like retinal holes that requiredtreatment with laser. Conclusions: We demostratedthat true changes are evidenced at thevitreous post Lasik. Posterior vitreous detachmentis the most significant discovery and itcould be implied in the genesis of tears anddetachment of the retina, but its incidence is evensmaller than in the general population and thisallows refractive surgery to remain as a

  4. Crystalline lens radioprotectors

    International Nuclear Information System (INIS)

    Belkacemi, Y.; Pasquier, D.; Castelain, B.; Lartigau, E.; Warnet, J.M.

    2003-01-01

    During more than a half of century, numerous compounds have been tested in different models against radiation-induced cataract. In this report, we will review the radioprotectors that have been already tested for non-human crystalline lens protection. We will focus on the most important published studies in this topic and the mechanisms of cyto-protection reported in. vitro and in. vivo from animals. The most frequent mechanisms incriminated in the cyto-protective effect are: free radical scavenging, limitation of lipid peroxidation, modulation of cycle progression increase of intracellular reduced glutathione pool, reduction of DNA strand breaks and limitation of apoptotic cell death. Arnifostine (or Ethyol) and anethole dithiolethione (or Sulfarlem), already used clinically as chemo- and radio-protectants, could be further test?r for ocular radioprotection particularly for radiation-induced cataract. (author)

  5. Wedged multilayer Laue lens

    International Nuclear Information System (INIS)

    Conley, Ray; Liu Chian; Qian Jun; Kewish, Cameron M.; Macrander, Albert T.; Yan Hanfei; Maser, Joerg; Kang, Hyon Chol; Stephenson, G. Brian

    2008-01-01

    A multilayer Laue lens (MLL) is an x-ray focusing optic fabricated from a multilayer structure consisting of thousands of layers of two different materials produced by thin-film deposition. The sequence of layer thicknesses is controlled to satisfy the Fresnel zone plate law and the multilayer is sectioned to form the optic. An improved MLL geometry can be created by growing each layer with an in-plane thickness gradient to form a wedge, so that every interface makes the correct angle with the incident beam for symmetric Bragg diffraction. The ultimate hard x-ray focusing performance of a wedged MLL has been predicted to be significantly better than that of a nonwedged MLL, giving subnanometer resolution with high efficiency. Here, we describe a method to deposit the multilayer structure needed for an ideal wedged MLL and report our initial deposition results to produce these structures

  6. NMR Spectroscopy of the Hydrated Layer of Composite Particles Based on Nanosized Al2O3 and Vitreous Humor

    Science.gov (United States)

    Turov, V. V.; Gerashchenko, I. I.; Markina, A. I.

    2013-11-01

    The hydrated layer of composite particles prepared using Al2O3 and cattle vitreous humor was investigated using NMR spectroscopy. It was found that water bound to Al2O3 nanoparticles was present in the form of clusters with different degrees of association and energies of interaction with the surface. Water bound to the surface of the Al2O3/vitreous humor composite became more uniform upon immobilization of vitreous humor components on the surface of the Al2O3. With this, the clusters of adsorbed water had characteristics that were close to those found in air and weakly polar CHCl3 media. Addition of polar CH3CN led to the formation of very small water clusters. PMR spectra of the surface of the Al2O3/vitreous humor composite in the presence of trifluoroacetic acid differentiated four types of hydrated structures that differed in the degree of water association.

  7. A direct, single-step plasma arc-vitreous ceramic process for stabilizing spent nuclear fuels, sludges, and associated wastes

    International Nuclear Information System (INIS)

    Feng, X.; Einziger, R.E.; Eschenbach, R.C.

    1997-01-01

    A single-step plasma arc-vitreous ceramic (PAVC) process is described for converting spent nuclear fuel (SNF), SNF sludges, and associated wastes into a vitreous ceramic waste form. This proposed technology is built on extensive experience of nuclear waste form development and nuclear waste treatment using the commercially available plasma arc centrifugal (PAC) system. SNF elements will be loaded directly into a PAC furnace with minimum additives and converted into vitreous ceramics with up to 90 wt% waste loading. The vitreous ceramic waste form should meet the functional requirements for borosilicate glasses for permanent disposal in a geologic repository and for interim storage. Criticality safety would be ensured through the use of batch modes, and controlling the amount of fuel processed in one batch. The minimum requirements on SNF characterization and pretreatment, the one-step process, and minimum secondary waste generation may reduce treatment duration, radiation exposure, and treatment cost

  8. [Iris hooks and modified capsular tension ring for subluxation lens in patients with Marfan's syndrome].

    Science.gov (United States)

    Wu, Wen-Jie; Zheng, Dan-ying; Zheng, Ying-feng; Cai, Xiao-yu

    2007-02-01

    To evaluate clinical efficiency and safety of the iris hooks and modified capsular tension ring (MCTR) for the treatment of subluxation lens in patients with Marfan's syndrome. This study comprised 5 patients (7 eyes) with Marfan's syndrome and subluxation lens. After 3.2 mm clear cornea incision and continuous curvilinear capsulorhexis (CCC), 2 - 4 disposable nylon iris hooks were inserted through the stab incisions and placed in the capsulorhexis to support the capsule and enlarged the CCC. Following irrigation/aspiration, a MCTR with suture in its eyelet was placed in the capsule bag. After tightening and tying the suture of MCTR, the capsular bag was centered and fixed. A foldable AcrySof one-piece intraocular lens (IOL) was then placed in the capsule bag. Twelve months after the operation, the best corrected visual acuity was >/= 0.8 in six eyes and 0.7 in one eye. The scheimpflug images obtained from the Pentacam demonstrated that the IOL were well centered. UBM showed that all the MCTR and the haptics of the IOL were in the capsule bag, the eyelet of the MCTR was rested stably between the capsulorhexis margin and the iris. The retroillumination photograph indicated that only one eye had obvious posterior capsular opacification. No intraoperative and postoperative complications such as prolapse of vitreous and retina detachment was occurred. The iris hooks can provide excellent intraoperative capsule-lens stability and facilitate the manipulation during operation. MCTR allows additional suture fixation to the eye wall without damaging the capsular bag and maintains the long-term stability of the intraocular lens. Furthermore, MCTR is helpful for avoiding dislocation of the IOL due to progressive weakening of the zonular fibers in some patients and provides long-term safety.

  9. Flanged Intrascleral Intraocular Lens Fixation with Double-Needle Technique.

    Science.gov (United States)

    Yamane, Shin; Sato, Shimpei; Maruyama-Inoue, Maiko; Kadonosono, Kazuaki

    2017-08-01

    To report the clinical outcomes of a new technique for transconjunctival intrascleral fixation of an intraocular lens (IOL). Prospective, noncomparative, interventional case series. One hundred eyes of 97 consecutive patients with aphakia, dislocated IOL, or subluxated crystalline lens who underwent posterior chamber sutureless implantation of an IOL were studied. Two angled incisions parallel to the limbus were made by 30-gauge thin-wall needles. Haptics of an IOL were externalized with the needles and cauterized to make a flange of the haptics. The flange of the haptics were pushed back and fixed into the scleral tunnels. Best-corrected visual acuity (VA), corneal endothelial cell density, IOL tilt, and complications were determined. The IOLs were fixed with exact centration and axial stability. The mean preoperative best-corrected VA was 0.25 logarithm of the minimum angle of resolution (logMAR) units; after surgery, it improved significantly to 0.11 logMAR, 0.09 logMAR, 0.12 logMAR, and 0.04 logMAR at 6, 12, 24, and 36 months, respectively (P IOL tilt was 3.4°±2.5°. The postoperative complications included iris capture by the IOL in 8 eyes (8%), vitreous hemorrhage in 5 eyes (5%), and cystoid macular edema in 1 eye (1%). There were no incidents of postoperative retinal detachment, endophthalmitis, or IOL dislocation. We have developed a new technique for intrascleral IOL fixation. The flanged IOL fixation technique is a simple and minimally invasive method for achieving good IOL fixation with firm haptic fixation. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  10. Comparative kinetics of serum and vitreous humor digoxin concentrations in a guinea pig model. Part I: Intravenous administration of digoxin

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, B.; Balkon, J.; Bidanset, J.H.; Belmonte, A.; Barletta, M.; Manning, T. (Department of Pharmaceutical Sciences, College of Pharmacy and Allied Health Professions, St. John' s University, Jamaica, NY (USA))

    1991-03-01

    The pharmacokinetics of a single intravenous dose of digoxin in the guinea pig was investigated with emphasis on the penetration of digoxin into the vitreous humor. A controlled study was undertaken and data was collected which indicated that digoxin follows an open, two-compartment pharmacokinetic model with a terminal half-life of 318 minutes. The data indicated that the ratio of vitreous concentrations to serum concentrations were determined to be equal following an initial tissue distribution phase.

  11. Comparative kinetics of serum and vitreous humor digoxin concentrations in a guinea pig model. Part I: Intravenous administration of digoxin

    International Nuclear Information System (INIS)

    Donnelly, B.; Balkon, J.; Bidanset, J.H.; Belmonte, A.; Barletta, M.; Manning, T.

    1991-01-01

    The pharmacokinetics of a single intravenous dose of digoxin in the guinea pig was investigated with emphasis on the penetration of digoxin into the vitreous humor. A controlled study was undertaken and data was collected which indicated that digoxin follows an open, two-compartment pharmacokinetic model with a terminal half-life of 318 minutes. The data indicated that the ratio of vitreous concentrations to serum concentrations were determined to be equal following an initial tissue distribution phase

  12. Prenatal Diagnosis of Persistent Hyperplastic Primary Vitreous: Report of 2 Cases and Review of the Literature.

    Science.gov (United States)

    Esmer, Aytul Corbacioglu; Sivrikoz, Tugba Sarac; Gulec, Elif Yilmaz; Sezer, Salim; Kalelioglu, Ibrahim; Has, Recep; Yuksel, Atil

    2016-10-01

    Persistent hyperplastic primary vitreous is a spectrum of congenital ocular abnormalities characterized by leukocoria, microphthalmia, cataracts, extensive intravitreal hemorrhage, persistence of the hyaloid artery, glaucoma, and retinal detachment. It might be isolated or associated with congenital syndromes such as trisomy 13, Walker-Warburg syndrome, and Norrie disease. We present 2 cases of persistent hyperplastic primary vitreous diagnosed by prenatal sonography in the early third trimester. Bilateral hyperechoic lenses and retinal nonattachment were detected in the sonographic examination of the first case, whereas irregular echogenic bands between the lenses and posterior walls of the eyes were prominent in the second case. In both of the cases, ocular findings were accompanied by intracranial findings, including severe hydrocephalus, an abnormal gyral pattern, and cerebellar hypoplasia, suggesting the diagnosis of Walker-Warburg syndrome. We also present a review of the literature regarding the prenatal diagnosis of this malformation.

  13. Detection of Elevated Signaling Amino Acids in Human Diabetic Vitreous by Rapid Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Miao-Jen Lu

    2007-01-01

    Full Text Available Elevated glutamate is implicated in the pathology of PDR. The ability to rapidly assess the glutamate and amino acid content of vitreous provides a more complete picture of the chemical changes occurring at the diabetic retina and may lead to a better understanding of the pathology of PDR. Vitreous humor was collected following vitrectomies of patients with PDR and control conditions of macular hole or epiretinal membrane. A capillary electrophoresis method was developed to quantify glutamate and arginine. The analysis is relatively fast (<6 minutes and utilizes a poly(ethyleneoxide and sodium dodecylsulfate run buffer. Both amino acid levels show significant increases in PDR patients versus controls and are comparable to other reports. The levels of vitreal glutamate vary inversely with the degree of observed hemorrhage. The results demonstrate a rapid method for assessment of a number of amino acids to characterize the chemical changes at the diabetic retina to better understand tissue changes and potentially identify new treatments.

  14. Compliance among soft contact lens wearers.

    Science.gov (United States)

    Kuzman, Tomislav; Kutija, Marija Barisić; Masnec, Sanja; Jandroković, Sonja; Mrazovac, Danijela; Jurisić, Darija; Skegro, Ivan; Kalauz, Miro; Kordić, Rajko

    2014-12-01

    Contact lens compliance is proven to be crucial for preventing lens wear-related complications because of the interdependence of the steps in lens care regime and their influence on lens system microbial contamination. Awareness of the patients' lens handling compliance as well as correct recognition of non-compliant behaviours is the basis for creating more targeted strategies for patient education. The aim of this study was to investigate compliance among soft contact lens (SCL) wearers in different aspects of lens care handling and wearing habits. In our research 50 asymptomatic lens wearers filled out a questionnaire containing demographic data, lens type, hygiene and wearing habits, lenses and lens care system replacement schedule and self-evaluation of contact lens handling hygiene. We established criteria of compliance according to available manufacturer's recommendations, prior literature and our clinical experience. Only 2 (4%) of patients were fully compliant SCL wearers. The most common non-compliant behaviours were insufficient lens solution soaking time (62%), followed by failure to daily exchange lens case solution and showering while wearing lenses. 44% of patients reported storing lenses in saline solution. Mean lens storage case replacement was 3.6 months, with up to 78% patients replacing lens case at least once in 3 months. Average grade in self evaluating level of compliance was very good (4 +/- 0.78) (from 1-poor level of hygiene to 5-great level of hygiene). Lens wearers who reported excessive daily lens wear and more than 10 years of lens wearing experience were also found to be less compliant with other lens system care procedures. (t = -2.99, df=47, p rate, self grading was relatively high. Therefore, these results indicate the need for patient education and encouragement of better lens wearing habits and all of the lens maintenance steps at each patient visit.

  15. Universal viscosity growth in metallic melts at megabar pressures: the vitreous state of the Earth's inner core

    International Nuclear Information System (INIS)

    Brazhkin, Vadim V; Lyapin, A G

    2000-01-01

    Experimental data on and theoretical models for the viscosity of various types of liquids and melts under pressure are reviewed. Experimentally, the least studied melts are those of metals, whose viscosity is considered to be virtually constant along the melting curve. The authors' new approach to the viscosity of melts involves the measurement of the grain size in solidified samples. Measurements on liquid metals at pressures up to 10 GPa using this method show, contrary to the empirical approach, that the melt viscosity grows considerably along the melting curves. Based on the experimental data and on the critical analysis of current theories, a hypothesis of a universal viscosity behavior is introduced for liquids under pressure. Extrapolating the liquid iron results to the pressures and temperatures at the Earth's core reveals that the Earth's outer core is a very viscous melt with viscosity values ranging from 10 2 Pa s to 10 11 Pa s depending on the depth. The Earth's inner core is presumably an ultraviscous (>10 11 Pa s) glass-like liquid - in disagreement with the current idea of a crystalline inner core. The notion of the highly viscous interior of celestial bodies sheds light on many mysteries of planetary geophysics and astronomy. From the analysis of the pressure variation of the melting and glass-transition temperatures, an entirely new concept of a stable metallic vitreous state arises, calling for further experimental and theoretical study. (reviews of topical problems)

  16. Contact Lens-Related Eye Infections

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Contact Lens-Related Eye Infections Sections Contact Lens-Related Eye ... Six Steps to Avoid Contact Lens Infections Contact Lens-Related Eye Infections Leer en Español: Infecciones relacionadas ...

  17. 21 CFR 886.1375 - Bagolini lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bagolini lens. 886.1375 Section 886.1375 Food and... OPHTHALMIC DEVICES Diagnostic Devices § 886.1375 Bagolini lens. (a) Identification. A Bagolini lens is a device that consists of a plane lens containing almost imperceptible striations that do not obscure...

  18. Straylight Measurements in Contact Lens Wear

    NARCIS (Netherlands)

    van der Meulen, Ivanka J. E.; Engelbrecht, Leonore A.; van Vliet, Johannes M. J.; Lapid-Gortzak, Ruth; Nieuwendaal, Carla P.; Mourits, Maarten P.; Schlingemann, Reinier O.; van den Berg, Thomas J. T. P.

    2010-01-01

    Purpose: (1) To quantify the effect of contact lens wear on straylight in rigid and soft contact lens wearers and (2) to relate findings to morphological changes and subjective complaints. Methods: Straylight was measured using the Oculus C-Quant during contact lens wear and after contact lens

  19. Motorized injector-assisted intrascleral intraocular lens fixation.

    Science.gov (United States)

    Hung, Jia-Horung; Wang, Shih-Hao; Teng, Yu-Ti; Hsu, Sheng-Min

    2017-03-01

    For eyes with deficient capsular support, intraocular lens (IOL) implantation has long been a technical challenge. Recently, intrascleral fixation of the haptics of a three-piece posterior chamber IOL has become a popular option. In this procedure, externalization of the leading haptic during IOL injection is a stressful step. We present a modified technique to improve the ease and safety of this step. Our modified technique involves IOL injection with a motorized injector with several important modifications described here. With these modifications, a surgeon can easily maintain the correct orientation of the IOL in a well-controlled manner during IOL injection. The records of 13 patients who underwent this technique were retrospectively evaluated. Corrected-distance visual acuity improved significantly after surgery (pIOL decentration, or vitreous hemorrhage was noted during the follow-up period. In conclusion, the motorized injector-assisted intrascleral IOL fixation technique is a safe and effective alternative to the conventional procedure. This technique makes the process of leading haptic externalization easier and more controllable. Copyright © 2017. Published by Elsevier Taiwan.

  20. Motorized injector-assisted intrascleral intraocular lens fixation

    Directory of Open Access Journals (Sweden)

    Jia-Horung Hung

    2017-03-01

    Full Text Available For eyes with deficient capsular support, intraocular lens (IOL implantation has long been a technical challenge. Recently, intrascleral fixation of the haptics of a three-piece posterior chamber IOL has become a popular option. In this procedure, externalization of the leading haptic during IOL injection is a stressful step. We present a modified technique to improve the ease and safety of this step. Our modified technique involves IOL injection with a motorized injector with several important modifications described here. With these modifications, a surgeon can easily maintain the correct orientation of the IOL in a well-controlled manner during IOL injection. The records of 13 patients who underwent this technique were retrospectively evaluated. Corrected-distance visual acuity improved significantly after surgery (p<0.05. No postoperative retinal detachment, endophthalmitis, IOL decentration, or vitreous hemorrhage was noted during the follow-up period. In conclusion, the motorized injector-assisted intrascleral IOL fixation technique is a safe and effective alternative to the conventional procedure. This technique makes the process of leading haptic externalization easier and more controllable.

  1. [Evaluation of the modified capsular tension ring in cases of traumatic lens subluxation].

    Science.gov (United States)

    Marques, Daniela Meira Villano; Marques, Frederico França; Cionni, Robert J; Osher, Robert Henry; Freitas, Lincoln Lemes

    2007-01-01

    To evaluate the behavior of the modified capsular tension ring (MCTR) in traumatic subluxated cataracts analyzing the visual acuity, centration of the capsular bag, pseudophacodonesis, postoperative follow-up and intra- and postoperative complications. Cincinnati Eye Institute, Cincinnati, Ohio, USA. Twenty-two eyes of 22 patients with traumatic loss of zonular support had phacoemulsification using PCIOL and MCTR implantation. The preoperative examination included best correct visual acuity (BCVA) and the presence or absence of phacodonesis, lens decentration and vitreous prolapse. The postoperative evaluation included BCVA, the presence of pseudophacodonesis, PCIOL centration, necessity of vitrectomy and other complications. 21 eyes (95.45%) had an improvement in BCVA. The preoperative examination disclosed phacodonesis in 11 eyes (50%) and no eye presented pseudophacodonesis in the postoperative period. Preoperatively, symptomatic decentration was presented by 10 eyes (45.45%) and 22 eyes (100%) had no decentration after surgery. The preoperative examination revealed vitreous prolapse in the anterior chamber in 9 eyes (40.90%). Vitrectomy was required in 11 eyes (50%). The use of the MCTR resulted in a good centration of the capsular bag and the PC IOL in 22 eyes with traumatic cataract and loss of zonular support.

  2. Sulfur Hexafluoride 20% versus Lactated Ringer′s solution for Prevention of Early Postoperative Vitreous Hemorrhage after Diabetic Vitrectomy

    Directory of Open Access Journals (Sweden)

    Fereydoun Farrahi

    2010-01-01

    Full Text Available Purpose: To compare the hemostatic effect of sulfur hexafluoride 20% (SF6 20% with lactated Ringer′s solution for prevention of early postoperative vitreous hemorrhage following diabetic vitrectomy. Methods: In a prospective randomized clinical trial, 50 eyes undergoing diabetic vitrectomy were divided into two groups. At the conclusion of surgery, in one group the vitreous cavity was filled with SF6 20% while in the other group lactated Ringer′s solution was retained in the vitreous cavity. The two groups were compared for the rate of early postoperative vitreous hemorrhage. Results: The incidence of vitreous hemorrhage was lower in the SF6 group than the Ringer′s group 4 days (20% vs 68%, P=0.001, 7 days (24% vs 60%, P=0.01 and 4 weeks (16% vs 40%, P=0.059 after vitrectomy. Conclusion: In comparison with lactated Ringer′s solution, SF6 20% had a significant hemostatic effect especially in the early postoperative period after diabetic vitrectomy and reduced the incidence of vitreous hemorrhage.

  3. A new and standardized method to sample and analyse vitreous samples by the Cellient automated cell block system.

    Science.gov (United States)

    Van Ginderdeuren, Rita; Van Calster, Joachim; Stalmans, Peter; Van den Oord, Joost

    2014-08-01

    In this prospective study, a universal protocol for sampling and analysing vitreous material was investigated. Vitreous biopsies are difficult to handle because of the paucity of cells and the gelatinous structure of the vitreous. Histopathological analysis of the vitreous is useful in difficult uveitis cases to differentiate uveitis from lymphoma or infection and to define the type of cellular reaction. Hundred consecutive vitreous samples were analysed with the Cellient tissue processor (Hologic). This machine is a fully automated processor starting from a specified container with PreservCyt (fixative fluid) with cells to paraffin. Cytology was compared with fixatives Cytolyt (contains a mucolyticum) and PreservCyt. Routine histochemical and immunostainings were evaluated. In 92% of the cases, sufficient material was found for diagnosis. In 14%, a Cytolyt wash was necessary to prevent clotting of the tubes in the Cellient due to the viscosity of the sample. In 23%, the diagnosis was an acute inflammation (presence of granulocytes); in 33%, chronic active inflammation (presence of T lymphocytes); in 33%, low-grade inflammation (presence of CD68 cells, without T lymphocytes); and in 3%, a malignant process. A standardized protocol for sampling and handling vitreous biopsies, fixing in PreservCyt and processing by the Cellient gives a satisfactory result in morphology, number of cells and possibility of immuno-histochemical stainings. The diagnosis can be established or confirmed in more than 90% of cases. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  4. Assessment and Comparison of Vitreous Humor as an Alternative Matrix for Forensic Toxicology Screening by GC-MS.

    Science.gov (United States)

    Metushi, Imir G; Fitzgerald, Robert L; McIntyre, Iain M

    2016-05-01

    Alternative specimens have been occasionally considered as substitutes for whole blood for postmortem toxicology testing. We studied the applicability of vitreous humor, and evaluated whether it would be suitable to replace (or augment) whole blood for routine drug screening. Results showed that from 51 autopsy cases, we were able to identify an aggregate of 209 findings in whole blood compared with 169 in vitreous. The total number of compounds identified was 71 for whole blood and 60 for vitreous humor. Quantitative analysis showed that whole-blood concentrations of trazodone were several fold higher than vitreous humor concentrations (1.42 ± 0.57 vs. 0.15 ± 0.05 mg/L, respectively) and similar results were also obtained for diazepam (0.37 ± 0.06 vs. 0.13 ± 0.01, respectively). For other drugs such as oxycodone, hydrocodone and doxylamine, a trend suggesting higher concentrations in vitreous humor vs. whole blood was observed; however, this was not significant. Our results are consistent with the limited work of other investigators, and suggest that vitreous humor could be an appropriate matrix for drug screening in postmortem toxicology. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Immunohistochemical studies of lens crystallins in the dysgenetic lens (dyl) mutant mice

    NARCIS (Netherlands)

    Brahma, S.K.; Sanyal, S.

    1984-01-01

    The lens in the dyl mutant mice shows a persistent lens-ectodermal connection as well as degeneration and extrusion of lens materials after the initial differentiation of the fibres. Immunohistochemical investigation of the ontogeny of the lens crystallins in this developing mutant lens has been

  6. Electroplated reticulated vitreous carbon current collectors for lead-acid batteries: opportunities and challenges

    Science.gov (United States)

    Gyenge, Elod; Jung, Joey; Mahato, Basanta

    Reticulated, open-cell structures based on vitreous carbon substrates electroplated with a Pb-Sn (1 wt.%) alloy were investigated as current collectors for lead-acid batteries. Scanning and backscattered electron microscopy, cyclic voltammetry, anodic polarization and flooded 2 V single-cell battery testing was employed to characterize the performance of the proposed collectors. A battery equipped with pasted electroplated reticulated vitreous carbon (RVC) electrodes of 137 cm 2 geometric area, at the time of manuscript submission, completed 500 cycles and over 1500 h of continuous operation. The cycling involved discharges at 63 A kg PAM-1 corresponding to a nominal 0.75 h rate and a positive active mass (PAM) utilization efficiency of 21%. The charging protocol was composed of two voltage limited (i.e. 2.6 V/cell), constant current steps of 35 and 9.5 A kg PAM-1, respectively, with a total duration of about 2 h. The charge factor was 1.05-1.15. The observed cycling behavior in conjunction with the versatility of electrodeposition to produce application-dependent optimized lead alloy coating thickness and composition shows promise for the development of lead-acid batteries using electroplated reticulated vitreous carbon collectors.

  7. Inherited retinal dysplasia and persistent hyperplastic primary vitreous in Miniature Schnauzer dogs.

    Science.gov (United States)

    Grahn, Bruce H; Storey, Eric S; McMillan, Catherine

    2004-01-01

    The objectives of this study were to define the clinical syndrome of retinal dysplasia and persistent primary vitreous in Miniature Schnauzer dogs and determine the etiology. We examined 106 Miniature Schnauzers using a biomicroscope and indirect ophthalmoscope. The anterior and posterior segments of affected dogs were photographed. Four enucleated eyes were examined using routine light microscopy and scanning electron microscopy. A pedigree was constructed and related dogs were test-bred to define the mode of inheritance of this syndrome. Congenital retinal dysplasia was confirmed in 24 of 106 related Miniature Schnauzer dogs. Physical and postmortem examinations revealed that congenital abnormalities were limited to the eyes. Biomicroscopic, indirect ophthalmoscopic, and neuro-ophthalmic examinations confirmed that some of these dogs were blind secondary to bilateral retinal dysplasia and detachment (nonattachment) (n = 13), and the remainder had generalized retinal dysplasia (n = 11). Fifteen of these dogs were also diagnosed with unilateral (n = 9) or bilateral (n = 6) persistent hyperplastic primary vitreous. Nutritional, infectious, or toxic etiologies were not evident on physical, postmortem, light microscopic, or transmitting and scanning electron microscopic examination of four affected Miniature Schnauzers. We examined the pedigree and determined that an autosomal recessive mode of inheritance was most likely. Three test-bred litters including those from affected parents, carrier and affected parents, and carrier parents confirmed this mode of inheritance. This study confirms that retinal dysplasia and persistent hyperplastic primary vitreous is a congenital abnormality that is inherited as an autosomal recessive condition in Miniature Schnauzers.

  8. Disposable pipette extraction for gas chromatographic determination of codeine, morphine, and 6-monoacetylmorphine in vitreous humor.

    Science.gov (United States)

    Kovatsi, Leda; Rentifis, Konstantinos; Giannakis, Dimitrios; Njau, Samuel; Samanidou, Victoria

    2011-07-01

    The availability of a sensitive and rapid analytical method for the determination of opiates, and other substances of forensic interest, in a variety of biological specimens is of utmost importance to forensic laboratories. Solid-phase extraction is very popular in the pre-treatment of forensic samples. Nevertheless, a new approach, disposable pipette extraction (DPX), is gaining increasing interest in sample preparation. DPX has already been applied to the analysis of drugs of abuse in common biological matrices, such as urine and blood, but has not yet been evaluated on alternative biological samples, such as vitreous humor. The objective of this study was to evaluate the applicability of DPX on the analysis of opiates in vitreous humor. The currently developed method is fast, reliable, and easy to perform. The sensitivity, precision, and accuracy are satisfactory. Recoveries obtained are within the range of 72-91%, whereas the sample volume of vitreous humor required is only 100 μL. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Scleral depressed vitreous shaving, 360 laser, and perfluoropropane (C 3 F 8 for retinal detachment

    Directory of Open Access Journals (Sweden)

    Vivek Chaturvedi

    2014-01-01

    Full Text Available Purpose : To review the characteristics and outcomes of patients who underwent pars plana vitrectomy (PPV with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% C3F8 gas for rhegmatogenous retinal detachment (RRD. Materials and Methods : A retrospective review of a consecutive series of patients who underwent primary repair of RRD by PPV with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% perfluoropropane (C 3 F 8 was conducted. Patients with less than 3 months follow-up, previous retinal surgery, and higher than grade B proliferative vitreoretinopathy were excluded. Results : Ninety-one eyes were included in the study. The mean age was 60.1 years. The mean follow-up was 13.7 months. The macula was detached in 63% (58/91 of the eyes. The reattachment rate after one surgical procedure was 95% (86/91 while overall reattachment rate was 100%. There was no statistically significant difference between reattachment rates of superior, nasal/temporal, or inferior RRDs. The mean final best corrected visual acuity (BCVA was 20/40. Of all the patients, 66% of patients with macula-off RRDs had a final BCVA of 20/40 or better. Conclusions: PPV with scleral depressed vitreous shaving, 360 degree peripheral endolaser, and 14% C 3 F 8 leads to successful anatomical reattachment with visual improvement in patients with primary RRD.

  10. Prevalence and Associations of Incomplete Posterior Vitreous Detachment in Adult Chinese: The Beijing Eye Study

    Science.gov (United States)

    Shao, Lei; Xu, Liang; You, Qi Sheng; Wang, Ya Xing; Chen, Chang Xi; Yang, Hua; Zhou, Jin Qiong; Jonas, Jost B.; Wei, Wen Bin

    2013-01-01

    Purpose To determine prevalence and associations of incomplete posterior vitreous detachment (PVD). Methods The population-based cross-sectional Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range: 50–93 years). A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD-OCT). Incomplete PVD was differentiated into type 1 (shallow PVD with circular perifoveal vitreous attachment), type 2 (PVD reaching fovea but not foveola), type 3 (shallow PVD with pinpoint vitreous attachment at the foveola), and type 4 (PVD completely detached from the macula, attached to the optic disc). Results An incomplete PVD was detected in 3948 eyes (prevalence: 60.5±0.6%; 95% Confidence Interval (CI): 59.3%,61.7%) of 2198 subjects (67.1±0.8%;95%CI: 65.6%,68.7%). Type 1 PVD was seen in 3090 (78.3%) eyes, type 2 PVD in 504 (12.8%) eyes, type 3 PVD in 70 (1.8%) eyes, and type 4 PVD in 284 (7.2%) eyes. Prevalence of incomplete PVD was associated with younger age (PPVD was associated with higher age (PPVD (detected in 67.1% subjects) was associated with younger age, male gender, rural region of habitation, larger corneal diameter, better best corrected visual acuity and hyperopic refractive error. PMID:23544043

  11. Crystal diffraction lens for medical imaging

    International Nuclear Information System (INIS)

    Smither, R. K.; Roa, D. E.

    2000-01-01

    A crystal diffraction lens for focusing energetic gamma rays has been developed at Argonne National Laboratory for use in medical imaging of radioactivity in the human body. A common method for locating possible cancerous growths in the body is to inject radioactivity into the blood stream of the patient and then look for any concentration of radioactivity that could be associated with the fast growing cancer cells. Often there are borderline indications of possible cancers that could be due to statistical functions in the measured counting rates. In order to determine if these indications are false or real, one must resort to surgical means and take tissue samples in the suspect area. They are developing a system of crystal diffraction lenses that will be incorporated into a 3-D imaging system with better sensitivity (factors of 10 to 100) and better spatial resolution (a few mm in both vertical and horizontal directions) than most systems presently in use. The use of this new imaging system will allow one to eliminate 90% of the false indications and both locate and determine the size of the cancer with mm precision. The lens consists of 900 single crystals of copper, 4 mm x 4 mm on a side and 2--4 mm thick, mounted in 13 concentric rings

  12. Application of the ELDO approach to assess cumulative eye lens doses for interventional cardiologists

    International Nuclear Information System (INIS)

    Farah, J.; Jacob, S.; Clairand, I.; Struelens, L.; Vanhavere, F.; Auvinen, A.; Koukorava, C.; Schnelzer, M.

    2015-01-01

    In preparation of a large European epidemiological study on the relation between eye lens dose and the occurrence of lens opacities, the European ELDO project focused on the development of practical methods to estimate retrospectively cumulative eye lens dose for interventional medical professionals exposed to radiation. The present paper applies one of the ELDO approaches, correlating eye lens dose to whole-body doses, to assess cumulative eye lens dose for 14 different Finnish interventional cardiologists for whom annual whole-body dose records were available for their entire working period. The estimated cumulative left and right eye lens dose ranged from 8 to 264 mSv and 6 to 225 mSv, respectively. In addition, calculations showed annual eye lens doses sometimes exceeding the new ICRP annual limit of 20 mSv. The work also highlights the large uncertainties associated with the application of such an approach proving the need for dedicated dosimetry systems in the routine monitoring of the eye lens dose. (authors)

  13. Contact Lens Related Corneal Ulcer

    OpenAIRE

    Loh, KY; Agarwal, P

    2010-01-01

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

  14. Crystalline lens and refractive development.

    Science.gov (United States)

    Iribarren, Rafael

    2015-07-01

    Individual refractive errors usually change along lifespan. Most children are hyperopic in early life. This hyperopia is usually lost during growth years, leading to emmetropia in adults, but myopia also develops in children during school years or during early adult life. Those subjects who remain emmetropic are prone to have hyperopic shifts in middle life. And even later, at older ages, myopic shifts are developed with nuclear cataract. The eye grows from 15 mm in premature newborns to approximately 24 mm in early adult years, but, in most cases, refractions are maintained stable in a clustered distribution. This growth in axial length would represent a refractive change of more than 40 diopters, which is compensated by changes in corneal and lens powers. The process which maintains the balance between the ocular components of refraction during growth is still under study. As the lens power cannot be measured in vivo, but can only be calculated based on the other ocular components, there have not been many studies of lens power in humans. Yet, recent studies have confirmed that the lens loses power during growth in children, and that hyperopic and myopic shifts in adulthood may be also produced by changes in the lens. These studies in children and adults give a picture of the changing power of the lens along lifespan. Other recent studies about the growth of the lens and the complexity of its internal structure give clues about how these changes in lens power are produced along life. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Single lens laser beam shaper

    Science.gov (United States)

    Liu, Chuyu [Newport News, VA; Zhang, Shukui [Yorktown, VA

    2011-10-04

    A single lens bullet-shaped laser beam shaper capable of redistributing an arbitrary beam profile into any desired output profile comprising a unitary lens comprising: a convex front input surface defining a focal point and a flat output portion at the focal point; and b) a cylindrical core portion having a flat input surface coincident with the flat output portion of the first input portion at the focal point and a convex rear output surface remote from the convex front input surface.

  16. No turnover in lens lipids for the entire human lifespan.

    Science.gov (United States)

    Hughes, Jessica R; Levchenko, Vladimir A; Blanksby, Stephen J; Mitchell, Todd W; Williams, Alan; Truscott, Roger J W

    2015-03-11

    Lipids are critical to cellular function and it is generally accepted that lipid turnover is rapid and dysregulation in turnover results in disease (Dawidowicz 1987; Phillips et al., 2009; Liu et al., 2013). In this study, we present an intriguing counter-example by demonstrating that in the center of the human ocular lens, there is no lipid turnover in fiber cells during the entire human lifespan. This discovery, combined with prior demonstration of pronounced changes in the lens lipid composition over a lifetime (Hughes et al., 2012), suggests that some lipid classes break down in the body over several decades, whereas others are stable. Such substantial changes in lens cell membranes may play a role in the genesis of age-related eye disorders. Whether long-lived lipids are present in other tissues is not yet known, but this may prove to be important in understanding the development of age-related diseases.

  17. Monitoring of eye lens doses in radiation protection

    International Nuclear Information System (INIS)

    Bordy, J.M.

    2015-01-01

    Mainly due to the ICRP recommendation to decrease the exposure limit for eye lenses, the eye lens dosimetry has to be reconsidered. This paper gives an overview of the issues raised after this recommendation; that is to say, the choice and definition of the operational quantity to be monitored, the type testing and calibration of dosimeters aimed at measuring eyes lens 'doses', the design of existing eye lens dosimeters and their wearing conditions. Finally, a criterion to choose between a direct measurement of the personal dose equivalent at three millimeters depth, H p (3), with a dedicated dosimeter, and an indirect evaluation of H p (3) through whole-body monitoring is presented. (authors)

  18. A course in lens design

    CERN Document Server

    Velzel, Chris

    2014-01-01

    A Course in Lens Design is an instruction in the design of image-forming optical systems. It teaches how a satisfactory design can be obtained in a straightforward way. Theory is limited to a minimum, and used to support the practical design work. The book introduces geometrical optics, optical instruments and aberrations. It gives a description of the process of lens design and of the strategies used in this process. Half of its content is devoted to the design of sixteen types of lenses, described in detail from beginning to end. This book is different from most other books on lens design because it stresses the importance of the initial phases of the design process: (paraxial) lay-out and (thin-lens) pre-design. The argument for this change of accent is that in these phases much information can be obtained about the properties of the lens to be designed. This information can be used in later phases of the design. This makes A Course in Lens Design a useful self-study book, and a suitable basis for an intro...

  19. Establishment of a recessive mutant small-eye rat with lens involution and retinal detachment associated with partial deletion and rearrangement of the Cryba1 gene.

    Science.gov (United States)

    Yamada, Toshiyuki; Nanashima, Naoki; Shimizu, Takeshi; Nakazawa, Yosuke; Nakazawa, Mitsuru; Tsuchida, Shigeki

    2015-10-15

    From our stock of SDRs (Sprague-Dawley rats), we established a mutant strain having small opaque eyes and named it HiSER (Hirosaki small-eye rat). The HiSER phenotype is progressive and autosomal recessive. In HiSER eyes, disruption and involution of the lens, thickening of the inner nuclear layer, detachment and aggregation of the retina, rudimentary muscle in the ciliary body and cell infiltration in the vitreous humour were observed. Genetic linkage analysis using crossing with Brown Norway rat suggested that the causative gene(s) is located on chromosome 10. Microarray analysis showed that the expression level of the Cryba1 gene encoding βA3/A1-crystallin on chromosome 10 was markedly decreased in HiSER eyes. Genomic PCR revealed deletion of a 3.6-kb DNA region encompassing exons 4-6 of the gene in HiSERs. In HiSER eyes, a chimaeric transcript of the gene containing exons 1-3 and an approximately 250-bp sequence originating from the 3'-UTR of the Nufip2 gene, located downstream of the breakpoint in the opposite direction, was present. Whereas the chimaeric transcript was expressed in HiSER eyes, neither normal nor chimaeric βA3/A1-crystallin proteins were detected by Western blot analysis. Real-time RT (reverse transcription)-PCR analysis revealed that expression level of the Nufip2 gene in the HiSER eye was 40% of that in the SDR eye. These results suggest that the disappearance of the βA3/A1-crystallin protein and, in addition, down-regulation of the Nufip2 gene as a consequence of gene rearrangement causes the HiSER phenotype. © 2015 Authors; published by Portland Press Limited.

  20. Complication rate of posterior capsule rupture with vitreous loss during phacoemulsification at a Hawaiian cataract surgical center: a clinical audit

    Directory of Open Access Journals (Sweden)

    Chen M

    2014-02-01

    Full Text Available Ming Chen,1 Kara C LaMattina,2 Thomas Patrianakos,2 Surendar Dwarakanathan2 1Department of Surgery, Division of Ophthalmology, University of Hawaii, Honolulu, HI, USA; 2Division of Ophthalmology, John H Stroger, Jr Hospital of Cook County, Chicago, IL, USA Purpose: To compare the complication rate of posterior capsule rupture (PCR with vitreous loss during phacoemulsification at an ambulatory surgical center with published results as a clinical audit for quality control. Methods: A retrospective chart review of 3,339 consecutive patients who underwent routine phacoemulsification by four experienced private practice surgeons from January 1, 2011 to June 30, 2012 at The Surgical Suites, Honolulu, HI, USA. All cases with PCR and vitreous loss were identified and selected for the study. Risk factors of this complication were further examined. Data were sent to John H Stroger Jr Hospital of Cook County, Division of Ophthalmology, for literature review, analysis, and write-up. Results: Twenty-three of the 3,339 cases incurred PCR and vitreous loss during phacoemulsification, for an incidence rate of 0.68%. Miosis, shallow chamber, restlessness, pseudoexfoliation syndrome, floppy iris syndrome, and zonulopathy were the main causes. In addition, surgeon volume (number of cases was inversely correlated with PCR. Conclusion: The rate of PCR with vitreous loss during phacoemulsification in this study may be lower than other published results done at academic centers. However, there was no compatible study available for comparison, as existing studies performed at academic centers included resident cases. This study identified risk factors for PCR/vitreous loss both preoperatively and postoperatively that may assist in application of preventive measures to decrease rates of PCR/vitreous loss. Keywords: phacoemulsification complications, posterior capsule rupture, vitreous loss, vitrectomy, miosis, pseudoexfoliation, floppy iris syndrome, zonulopathy

  1. Association between aqueous humor and vitreous fluid levels of Th17 cell-related cytokines in patients with proliferative diabetic retinopathy.

    Science.gov (United States)

    Takeuchi, Masaru; Sato, Tomohito; Sakurai, Yutaka; Taguchi, Manzo; Harimoto, Kozo; Karasawa, Yoko; Ito, Masataka

    2017-01-01

    Inflammation is known to be involved in the progression of diabetic retinopathy. We have recently reported that vitreous levels of IL-4, IL-17A, IL-22, IL-31, and TNFα are higher than the respective serum levels in proliferative diabetic retinopathy (PDR) patients, and that vitreous levels of these cytokines are higher in PDR than in other non-inflammatory vitreoretinal diseases or uveitis associated with sarcoidosis. In the present study, we investigated inflammatory cytokines including Th17 cell-related cytokines in aqueous humor samples obtained from eyes with PDR, and analyzed the association between the aqueous humor and vitreous fluid levels of individual cytokines. The study group consisted of 31 consecutive type 2 diabetic patients with PDR who underwent cataract surgery and vitrectomy for vitreous hemorrhage and/or tractional retinal detachment. Undiluted aqueous humor was collected during cataract surgery, and then vitreous fluid was obtained using a 25G vitreous cutter inserted into the mid-vitreous cavity at the beginning of vitrectomy. IL-1β, IL-4, IL-6, IL-10, IL-17A, IL-17F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, IFN-γ, soluble CD40 ligand (sCD40L), and TNFα levels in the aqueous humor and vitreous fluid were measured using a beads-array system. Although IL-17A was detected in the aqueous humor of eyes with PDR and the level correlated with IL-17A level in the vitreous fluid, both percent detectable and level of IL-17A in the aqueous humor were significantly lower than those in the vitreous fluid. Vitreous IL-17A level was related significantly to IL-10, IL-22, and TNFα levels in aqueous humor as well as in vitreous fluid, On the other hand, aqueous IL-17A level was not related significantly to aqueous or vitreous levels of IL-10, IL-22 or TNFα level. The present study demonstrated that IL-17A level and detectable rate in the aqueous humor of patients with PDR are markedly lower than those in the vitreous fluid and aqueous IL-17A does not

  2. Eye lens monitoring for interventional radiology personnel: dosemeters, calibration and practical aspects of Hp(3) monitoring. A 2015 review

    International Nuclear Information System (INIS)

    Carinou, Eleftheria; Ferrari, Paolo; Bjelac, Olivera Ciraj; Gingaume, Merce; Merce, Marta Sans; O’Connor, Una

    2015-01-01

    A thorough literature review about the current situation on the implementation of eye lens monitoring has been performed in order to provide recommendations regarding dosemeter types, calibration procedures and practical aspects of eye lens monitoring for interventional radiology personnel. Most relevant data and recommendations from about 100 papers have been analysed and classified in the following topics: challenges of today in eye lens monitoring; conversion coefficients, phantoms and calibration procedures for eye lens dose evaluation; correction factors and dosemeters for eye lens dose measurements; dosemeter position and influence of protective devices. The major findings of the review can be summarised as follows: the recommended operational quantity for the eye lens monitoring is H p (3). At present, several dosemeters are available for eye lens monitoring and calibration procedures are being developed. However, in practice, very often, alternative methods are used to assess the dose to the eye lens. A summary of correction factors found in the literature for the assessment of the eye lens dose is provided. These factors can give an estimation of the eye lens dose when alternative methods, such as the use of a whole body dosemeter, are used. A wide range of values is found, thus indicating the large uncertainty associated with these simplified methods. Reduction factors from most common protective devices obtained experimentally and using Monte Carlo calculations are presented. The paper concludes that the use of a dosemeter placed at collar level outside the lead apron can provide a useful first estimate of the eye lens exposure. However, for workplaces with estimated annual equivalent dose to the eye lens close to the dose limit, specific eye lens monitoring should be performed. Finally, training of the involved medical staff on the risks of ionising radiation for the eye lens and on the correct use of protective systems is strongly recommended. (review)

  3. Intravitreal Ranibizumab Injection as an Adjuvant in the Treatment of Neovascular Glaucoma Accompanied by Vitreous Hemorrhage after Diabetic Vitrectomy

    Directory of Open Access Journals (Sweden)

    Xi Shen

    2016-01-01

    Full Text Available Purpose. To determine the efficacy of intravitreal ranibizumab injection as adjuvant therapy in the treatment of neovascular glaucoma (NVG accompanied by postvitrectomy diabetic vitreous hemorrhage (PDVH. Methods. Eighteen NVG patients (18 eyes accompanied by PDVH were enrolled in this prospective, monocenter, 12-month, interventional case series. The consecutive 18 patients with an IOP ≥ 25 mmHg despite being treated with the maximum medical therapy were treated with intravitreal ranibizumab injections. Vitreous surgery or/with Ahmed valve implantation were indicated if no clinical improvement in vitreous haemorrhage and uncontrolled IOP was shown. Results. Ten patients got clear vitreous and controlled IOP only with 2.7±1.8 injections of ranibizumab without additional surgery. Vitrectomy or/with Ahmed valve implantation was administered in the other 8 eyes due to uncontrolled VH and IOP. At follow-up month 12, all the 18 eyes gained clear vitreous. At month 12 BCVA improved significantly compared to baseline. The baseline and follow-up at month 12 IOP/medication usage were 36.7±8.1 mmHg on 3.4±0.7 medications and 16.2±4.9 mmHg on 0.67±0.77 medications, respectively. Conclusions. The findings suggest that intravitreal ranibizumab injection as adjuvant therapy for treatment of NVG accompanied by PDVH may be safe and potentially effective. This clinical trial is registered with NCT02647515.

  4. Curiosity's Mars Hand Lens Imager (MAHLI) Investigation

    Science.gov (United States)

    Edgett, Kenneth S.; Yingst, R. Aileen; Ravine, Michael A.; Caplinger, Michael A.; Maki, Justin N.; Ghaemi, F. Tony; Schaffner, Jacob A.; Bell, James F.; Edwards, Laurence J.; Herkenhoff, Kenneth E.; Heydari, Ezat; Kah, Linda C.; Lemmon, Mark T.; Minitti, Michelle E.; Olson, Timothy S.; Parker, Timothy J.; Rowland, Scott K.; Schieber, Juergen; Sullivan, Robert J.; Sumner, Dawn Y.; Thomas, Peter C.; Jensen, Elsa H.; Simmonds, John J.; Sengstacken, Aaron J.; Wilson, Reg G.; Goetz, Walter

    2012-01-01

    The Mars Science Laboratory (MSL) Mars Hand Lens Imager (MAHLI) investigation will use a 2-megapixel color camera with a focusable macro lens aboard the rover, Curiosity, to investigate the stratigraphy and grain-scale texture, structure, mineralogy, and morphology of geologic materials in northwestern Gale crater. Of particular interest is the stratigraphic record of a ?5 km thick layered rock sequence exposed on the slopes of Aeolis Mons (also known as Mount Sharp). The instrument consists of three parts, a camera head mounted on the turret at the end of a robotic arm, an electronics and data storage assembly located inside the rover body, and a calibration target mounted on the robotic arm shoulder azimuth actuator housing. MAHLI can acquire in-focus images at working distances from ?2.1 cm to infinity. At the minimum working distance, image pixel scale is ?14 μm per pixel and very coarse silt grains can be resolved. At the working distance of the Mars Exploration Rover Microscopic Imager cameras aboard Spirit and Opportunity, MAHLI?s resolution is comparable at ?30 μm per pixel. Onboard capabilities include autofocus, auto-exposure, sub-framing, video imaging, Bayer pattern color interpolation, lossy and lossless compression, focus merging of up to 8 focus stack images, white light and longwave ultraviolet (365 nm) illumination of nearby subjects, and 8 gigabytes of non-volatile memory data storage.

  5. Dose limits to the eye lens

    Energy Technology Data Exchange (ETDEWEB)

    Sion, N.

    2016-09-15

    Protecting the human body from the effects of ionizing radiation is essential to forestall stochastic effects and require placing limits on the effective dose. Dose limits on specific organs are also necessary to reduce the deterministic effects and tissue reactions. The standard for radiation protection was ISO 15382 (2002) which mainly dealt with beta radiation for nuclear power plant workers. Clearly an update is required to allow for new technology and the proliferative use of radiation in medical practices. There is a need for more explicit radiation monitoring to operators and staff. ICRP118 (International Commission on Radiological Protection), Ref. 1, evolved their recommendations to include eye lens doses as a follow on to their publication 103 and to focus on radiation exposures. It provides updated estimates of 'practical' threshold doses for tissue injury at the level of 1% incidence. This paper discusses the current status and the recommendation for a drastic reduction of the dose limit to the eye lens. (author)

  6. Tinting of intraocular lens implants

    Energy Technology Data Exchange (ETDEWEB)

    Zigman, S.

    1982-06-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users.

  7. Tinting of intraocular lens implants

    International Nuclear Information System (INIS)

    Zigman, S.

    1982-01-01

    Intraocular lens (IOL) implants of polymethyl methacrylate (PMMA) lack an important yellow pigment useful as a filter in the visual process and in the protection of the retina from short-wavelength radiant energy. The ability to produce a yellow pigment in the PMMA used in IOL implants by exposure to near-ultraviolet (UV) light was tested. It was found that the highly cross-linked material in Copeland lens blanks was tinted slightly because of this exposure. The absorptive properties of lens blanks treated with near-UV light in this way approached that of the absorptive properties of human lenses. This finding shows that it is possible to alter IOL implants simply so as to induce a pale-yellow pigment in them to improve the visual process and to protect the retinas of IOL users

  8. Automated Fresnel lens tester system

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.S.

    1981-07-01

    An automated data collection system controlled by a desktop computer has been developed for testing Fresnel concentrators (lenses) intended for solar energy applications. The system maps the two-dimensional irradiance pattern (image) formed in a plane parallel to the lens, whereas the lens and detector assembly track the sun. A point detector silicon diode (0.5-mm-dia active area) measures the irradiance at each point of an operator-defined rectilinear grid of data positions. Comparison with a second detector measuring solar insolation levels results in solar concentration ratios over the image plane. Summation of image plane energies allows calculation of lens efficiencies for various solar cell sizes. Various graphical plots of concentration ratio data help to visualize energy distribution patterns.

  9. Early Vitreous Surgery in the Treatment of Aggressive Posterior Retinopathy of Prematurity

    Directory of Open Access Journals (Sweden)

    A. V. Tereshhenko

    2017-01-01

    Full Text Available The goal is to identify objective indications for early primary vitreous surgery in infants with aggressive posterior ROP and to develop a methodology. Patients and methods. The study included 20 preterm infants (40 eyes with aggressive posterior ROP at the stage of formation exudative-tractional retinal detachment, which were divided into two groups. The main group consisted of 10 infants (20 eyes with severe manifestations of aggressive posterior ROP. The control group included 10 premature infants (20 eyes with aggressive posterior ROP, who underwent transpupillary laser coagulation of the retina (LC. In all cases (20 eyes 5-8 days after LC was recorded the progression of the disease. Based on data from a complex ophthalmic examination, given the progression of the disease after LC in the control group and baseline severe aggressive posterior ROP in the main group with the control with identical clinical picture, patients in both groups was made early vitreous surgery: in the main group — after ophthalmological examination and control after 8-16 days after LC. Results. In the main group after 6 months in 15 eyes (75% formed the correct vitreomacular interface, in 5 cases (25% were diagnosed with the smoothness of the foveolar pits by sealing the internal limiting membrane with no signs of retinal edema. In the control group after 6 months in 6 eyes (30% formed the right macular interface in 11 (55% — was defined by flatness or lack foveolar pit with no signs of retinal edema. On 3 eyes (15% in the 2nd zone remained a local retinal detachment. Conclusion. Primary vitrectomy performed according to the developed indications, allows to optimize the treatment of patients with aggressive posterior ROP in cases of inefficiency of the LC. It is an alternative and pathogenetically substantiated technology, which efficiency is not inferior to the traditional approach, including LС followed by vitreous surgery.

  10. Mass diffusion coefficient measurement for vitreous humor using FEM and MRI

    Science.gov (United States)

    Rattanakijsuntorn, Komsan; Penkova, Anita; Sadha, Satwindar S.

    2018-01-01

    In early studies, the ‘contour method’ for determining the diffusion coefficient of the vitreous humor was developed. This technique relied on careful injection of an MRI contrast agent (surrogate drug) into the vitreous humor of fresh bovine eyes, and tracking the contours of the contrast agent in time. In addition, an analytical solution was developed for the theoretical contours built on point source model for the injected surrogate drug. The match between theoretical and experimental contours as a least square fit, while floating the diffusion coefficient, led to the value of the diffusion coefficient. This method had its limitation that the initial injection of the surrogate had to be spherical or ellipsoidal because of the analytical result based on the point-source model. With a new finite element model for the analysis in this study, the technique is much less restrictive and handles irregular shapes of the initial bolus. The fresh bovine eyes were used for drug diffusion study in the vitreous and three contrast agents of different molecular masses: gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA, 938 Da), non-ionic gadoteridol (Prohance, 559 Da), and bovine albumin conjugated with gadolinium (Galbumin, 74 kDa) were used as drug surrogates to visualize the diffusion process by MRI. The 3D finite element model was developed to determine the diffusion coefficients of these surrogates with the images from MRI. This method can be used for other types of bioporous media provided the concentration profile can be visualized (by methods such as MRI or fluorescence).

  11. New insight into the mechanism of cathodic electrodeposition of zinc oxide thin films onto vitreous carbon

    OpenAIRE

    Ait Ahmed , N.; Eyraud , M.; Hammache , H.; Vacandio , F.; Sam , S.; Gabouze , N.; Knauth , P.; Pelzer , K.; Djenizian , T.

    2014-01-01

    International audience; In this study, the mechanism of zinc oxide (ZnO) electrodeposition from aqueous zinc nitrate solution at 70°C was investigated on vitreous carbon and bulk zinc electrodes using cyclic voltammetry experiments. Mechanisms are presented for the ZnO formation: the first widely accepted route corresponds to ZnO precipitation from Zn 2+ and OH-produced by NO3-reduction; the second route, which is discussed in this article, is due to Zn 2+ reduction into metallic Zn followed ...

  12. Charged defects in chalcogenide vitreous semiconductors studied with combined Raman scattering and PALS methods

    International Nuclear Information System (INIS)

    Kavetskyy, T.; Vakiv, M.; Shpotyuk, O.

    2007-01-01

    A combination of Raman scattering and positron annihilation lifetime spectroscopy (PALS) techniques to study charged defects in chalcogenide vitreous semiconductors (ChVSs) was applied for the first time in this study. In the case of Ge 15.8 As 21 S 63.2 glass, it is found that the main radiation-induced switching of heteropolar Ge-S bonds into heteropolar As-S ones, previously detected by IR fast Fourier transform spectroscopy, can also be identified by Raman spectroscopy in the depolarized configuration. Results obtained by Raman scattering are in good agreement with PALS data for the investigated glass composition

  13. Charged defects in chalcogenide vitreous semiconductors studied with combined Raman scattering and PALS methods

    Energy Technology Data Exchange (ETDEWEB)

    Kavetskyy, T.; Vakiv, M. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); Shpotyuk, O. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine)], E-mail: shpotyuk@novas.lviv.ua

    2007-04-15

    A combination of Raman scattering and positron annihilation lifetime spectroscopy (PALS) techniques to study charged defects in chalcogenide vitreous semiconductors (ChVSs) was applied for the first time in this study. In the case of Ge{sub 15.8}As{sub 21}S{sub 63.2} glass, it is found that the main radiation-induced switching of heteropolar Ge-S bonds into heteropolar As-S ones, previously detected by IR fast Fourier transform spectroscopy, can also be identified by Raman spectroscopy in the depolarized configuration. Results obtained by Raman scattering are in good agreement with PALS data for the investigated glass composition.

  14. Application of positron annihilation lifetime technique for {gamma}-irradiation stresses study in chalcogenide vitreous semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O.; Golovchak, R.; Kovalskiy, A. [Scientific Research Company ' ' Carat' ' , Stryjska str. 20279031 Lviv (Ukraine); Filipecki, J.; Hyla, M. [Physics Institute, Pedagogical University, Al. Armii Krajowej 13/1542201 Czestochowa (Poland)

    2002-08-01

    The influence of {gamma}-irradiation on the positron annihilation lifetime spectra in chalcogenide vitreous semiconductors of As-Ge-S system has been analysed. The correlations between lifetime data, structural features and chemical compositions of glasses have been discussed. The observed lifetime components are connected with bulk positron annihilation and positron annihilation on various native and {gamma}-induced open volume defects. It is concluded that after {gamma}-irradiation of investigated materials the {gamma}-induced microvoids based on S{sub 1}{sup -}, As{sub 2}{sup -}, and Ge{sub 3}{sup -} coordination defects play the major role in positron annihilation processes. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  15. Posterior Vitreous Detachment as Observed by Wide-Angle OCT Imaging.

    Science.gov (United States)

    Tsukahara, Mayuka; Mori, Keiko; Gehlbach, Peter L; Mori, Keisuke

    2018-04-06

    Posterior vitreous detachment (PVD) plays an important role in vitreoretinal interface disorders. Historically, observations of PVD using OCT have been limited to the macular region. The purpose of this study is to image the wide-angle vitreoretinal interface after PVD in normal subjects using montaged OCT images. An observational cross-sectional study. A total of 144 healthy eyes of 98 normal subjects aged 21 to 95 years (51.4±22.0 [mean ± standard deviation]). Montaged images of horizontal and vertical OCT scans through the fovea were obtained in each subject. Montaged OCT images. By using wide-angle OCT, we imaged the vitreoretinal interface from the macula to the periphery. PVD was classified into 5 stages: stage 0, no PVD (2 eyes, both aged 21 years); stage 1, peripheral PVD limited to paramacular to peripheral zones (88 eyes, mean age 38.9±16.2 years, mean ± standard deviation); stage 2, perifoveal PVD extending to the periphery (12 eyes, mean age 67.9±8.4 years); stage 3, peripapillary PVD with persistent vitreopapillary adhesion alone (7 eyes, mean age 70.9±11.9 years); stage 4, complete PVD (35 eyes, mean age 75.1±10.1 years). All stage 1 PVDs (100%) were observed in the paramacular to peripheral region where the vitreous gel adheres directly to the cortical vitreous and retinal surface. After progression to stage 2 PVD, the area of PVD extends posteriorly to the perifovea and anteriorly to the periphery. Vitreoschisis was observed in 41.2% at PVD initiation (stage 1a). Whereas prior work suggests that PVD originates in the perifoveal region and after the sixth decade, our observations demonstrate that (1) PVD first appears even in the third decade of life and gradually appears more extensively throughout life; (2) more than 40% of eyes without fundus diseases at their PVD initiation are associated with vitreoschisis; and (3) PVD is first noted primarily in the paramacular-peripheral region where vitreous gel adheres to the retinal surface and is

  16. Lens system for SIMS analysis

    International Nuclear Information System (INIS)

    Martinez, G.; Sancho, M.; Garcia-Galan, J.C.

    1987-01-01

    A powerful version of the charge-density method is applied to the study of a combined objective and emission lens, suitable for highly localized analysis of a flat sample surface. This lens can extract secondary ions of equal or opposite polarity to that of the primary particles. A computer simulation of the ion trajectories for both modes is made. The behaviour for different values of the geometric parameters and polarizations is analyzed and useful data for design such as primary beam demagnification and secondary image position are given. (author) 4 refs

  17. An extended magnetic quadrupole lens for a high-resolution nuclear microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Breese, M.B.H. E-mail: m.breese@surrey.ac.uk; Grime, G.W.; Linford, W.; Harold, M

    1999-09-02

    This paper describes the design requirements and initial performance of a new style of magnetic quadrupole lens for use in a high-resolution nuclear microprobe, which is presently being constructed in Oxford. Such a microprobe necessitates the use of a small image distance from the exit face of the final quadrupole lens to the image plane in order to produce a large demagnification. This means that the final lens should be as close to the sample chamber as possible. However, with conventional magnetic quadrupoles the current-carrying coils protrude by a typical distance of 10-20 mm beyond the pole face, thereby significantly limiting the minimum image distance. The approach taken here is to recess the coils into the body of the lens, so that they are almost flush with the pole pieces and lens yoke, enabling an image distance of 55 mm. Three-dimensional magnetic field calculations within this lens structure predict that the field in the extended pole piece 'nose' region is only slightly less than that in the main lens body. Experimental field profiles, measured using a Hall probe, are used to confirm these calculations.

  18. An extended magnetic quadrupole lens for a high-resolution nuclear microprobe

    International Nuclear Information System (INIS)

    Breese, M.B.H.; Grime, G.W.; Linford, W.; Harold, M.

    1999-01-01

    This paper describes the design requirements and initial performance of a new style of magnetic quadrupole lens for use in a high-resolution nuclear microprobe, which is presently being constructed in Oxford. Such a microprobe necessitates the use of a small image distance from the exit face of the final quadrupole lens to the image plane in order to produce a large demagnification. This means that the final lens should be as close to the sample chamber as possible. However, with conventional magnetic quadrupoles the current-carrying coils protrude by a typical distance of 10-20 mm beyond the pole face, thereby significantly limiting the minimum image distance. The approach taken here is to recess the coils into the body of the lens, so that they are almost flush with the pole pieces and lens yoke, enabling an image distance of 55 mm. Three-dimensional magnetic field calculations within this lens structure predict that the field in the extended pole piece 'nose' region is only slightly less than that in the main lens body. Experimental field profiles, measured using a Hall probe, are used to confirm these calculations

  19. Molecular dynamics simulation of local structure and vibrational spectrum of uranyl (UO2)2+ in vitreous B2O3

    International Nuclear Information System (INIS)

    Zhuang, Z.-H.; Liu, G. K.; Beitz, J. V.

    2000-01-01

    Laser spectroscopic and extended X-ray absorption fine structure (EXAFS) spectra have shown that uranium in B 2 O 3 glass matrix forms uranyl in the electronic configuration of (UO 2 ) 2+ ,but its surrounding structure is not well known. Understanding of uranyl local structure, ion-ligand interaction, and chemical stability on the nanometer scale in glasses is essential in management of long-term performance of high-level nuclear wastes after disposal in a geologic repository. In the present work, the structure, phonon density of states, and vibrational spectrum of vitreous B 2 O 3 and the surrounding environment that contains a uranyl ion have been studied using a molecular dynamics (MD) simulation method that utilizes the Born-Mayer-Huggins and Coulomb pair potentials and the Stillinger-Weber three-body potential. A system of 406 ions was considered in our calculation. Simulation of a thermal quenching from 3000 K to 300 K was performed to generate a uniform and equilibrium model glass matrix before structure configuration and vibrational frequencies were obtained from the system. The structure of the simulated glass is in agreement with that reported by Krogh-Moe and Mozzi et al. The characteristic network of planar boroxol (B 3 O 6 ) rings is evident in the simulated system. A configuration of a U 6+ cation in the vitreous B 2 O 3 matrix is shown in Fig. 1. It is shown that a nearly linear (UO 2 ) 2+ uranyl ion is coordinated by four equatorial oxygen anions in an approximately planar arrangement. The U-O bond length is approximately 0.178 nm for the axial oxygen and 0.254 nm for the equatorial oxygen, which is in good agreement with the U-O distances obtained from fitting EXAFS spectra. Based on the simulated model structure, the uranyl vibrational spectrum is simulated and compared with experimental results obtained using site-selective fluorescence line narrowing (FLN) techniques

  20. Fraction of boroxol rings in vitreous boron oxide from a first-principles analysis of Raman and NMR spectra.

    Science.gov (United States)

    Umari, P; Pasquarello, Alfredo

    2005-09-23

    We determine the fraction f of B atoms belonging to boroxol rings in vitreous boron oxide through a first-principles analysis. After generating a model structure of vitreous B2O3 by first-principles molecular dynamics, we address a large set of properties, including the neutron structure factor, the neutron density of vibrational states, the infrared spectra, the Raman spectra, and the 11B NMR spectra, and find overall good agreement with corresponding experimental data. From the analysis of Raman and 11B NMR spectra, we yield consistently for both probes a fraction f of approximately 0.75. This result indicates that the structure of vitreous boron oxide is largely dominated by boroxol rings.

  1. Refractive lens exchange with a multifocal diffractive aspheric intraocular lens

    Directory of Open Access Journals (Sweden)

    Teresa Ferrer-Blasco

    2012-06-01

    Full Text Available PURPOSE: To evaluate the safety, efficacy and predictability after refractive lens exchange with multifocal diffractive aspheric intraocular lens implantation. METHODS: Sixty eyes of 30 patients underwent bilateral implantation with AcrySof® ReSTOR® SN6AD3 intraocular lens with +4.00 D near addition. Patients were divided into myopic and hyperopic groups. Monocular best corrected visual acuity at distance and near and monocular uncorrected visual acuity at distance and near were measured before and 6 months postoperatively. RESULTS: After surgery, uncorrected visual acuity was 0.08 ± 0.15 and 0.11 ± 0.14 logMAR for the myopic and hyperopic groups, respectively (50% and 46.67% of patients had an uncorrected visual acuity of 20/20 or better in the myopic and hyperopic groups, respectively. The safety and efficacy indexes were 1.05 and 0.88 for the myopic and 1.01 and 0.86 for the hyperopic groups at distance vision. Within the myopic group, 20 eyes remained unchanged after the surgery, and 3 gained >2 lines of best corrected visual acuity. For the hyperopic group, 2 eyes lost 2 lines of best corrected visual acuity, 21 did not change, and 3 eyes gained 2 lines. At near vision, the safety and efficacy indexes were 1.23 and 1.17 for the myopic and 1.16 and 1.13 for the hyperopic groups. Best corrected near visual acuity improved after surgery in both groups (from 0.10 logMAR to 0.01 logMAR in the myopic group, and from 0.10 logMAR to 0.04 logMAR in the hyperopic group. CONCLUSIONS: The ReSTOR® SN6AD3 intraocular lens in refractive lens exchange demonstrated good safety, efficacy, and predictability in correcting high ametropia and presbyopia.

  2. Morphometry and Lens of Eyes Bilih Fish (mystacoleucus padangensis, Bleeker) from Lake Toba, North Sumatra and Lake Singkarak, West Sumatra

    Science.gov (United States)

    Razak, A.

    2018-04-01

    This research has been carried out 2015. Bilih fish today need conservation and attention for sustainability. Habitat this fish is treated by human activities in Lake Singkarak, West Sumatera and Lake Toba in North Sumatera. The objectives of the research are describes morphometry of the body and relation with lens of eyes. The methods of the reasearch for measure all parts of surface body fish according www.fishbase.org. For measure and chemical composition of lens of eyes Bilih Fish (M. padangensis) are according Razak (2005). T he result of the research are indicated the size of morphology body Bilih Fish from Lake Toba and from Lake Singkarak is diffrent. Furthermore, diameter of lens is trend linier follow the growth of the body Bilih Fish from Lake Singkarak and Lake Toba. The chemical composition of lens of eyes Bilih Fish from Lake Singkarak contains Sulfur until 73.77% per 100 ppm, another substances like Calcium, Silicone, Magnesium, Phosporus 4.09%-4.83% per 100 ppm. The chemical composition of lens of eyes Bilih Fish from Lake Toba contains Sulfur only 50.08% per 100 ppm, another substances like Kalium, Calcium, Silicone, Magnesium, Phosporus 1.09%-10.43% per 100 ppm. Kalium substance only found in lens of eyes Bilih Fish from Lake Toba. As conclusion, morphometry body Bilih Fish from Lake Toba is bigger better than Bilih Fish from Lake Singkarak and chemical composition lens of eyes Bilih Fish from Lake Toba is influenced by environmental waters factors.

  3. Stretchable Binary Fresnel Lens for Focus Tuning

    NARCIS (Netherlands)

    Li, X.; Wei, L.; Poelma, R.H.; Vollebregt, S.; Wei, J.; Urbach, Paul; Sarro, P.M.; Zhang, G.Q.

    2016-01-01

    This paper presents a tuneable binary amplitude Fresnel lens produced by wafer-level microfabrication. The Fresnel lens is fabricated by encapsulating lithographically defined vertically aligned carbon nanotube (CNT) bundles inside a polydimethyl-siloxane (PDMS) layer. The composite lens material

  4. 21 CFR 886.1400 - Maddox lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Maddox lens. 886.1400 Section 886.1400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1400 Maddox lens. (a) Identification. A Maddox lens is a device...

  5. Crystalline lens power and refractive error.

    Science.gov (United States)

    Iribarren, Rafael; Morgan, Ian G; Nangia, Vinay; Jonas, Jost B

    2012-02-01

    To study the relationships between the refractive power of the crystalline lens, overall refractive error of the eye, and degree of nuclear cataract. All phakic participants of the population-based Central India Eye and Medical Study with an age of 50+ years were included. Calculation of the refractive lens power was based on distance noncycloplegic refractive error, corneal refractive power, anterior chamber depth, lens thickness, and axial length according to Bennett's formula. The study included 1885 subjects. Mean refractive lens power was 25.5 ± 3.0 D (range, 13.9-36.6). After adjustment for age and sex, the standardized correlation coefficients (β) of the association with the ocular refractive error were highest for crystalline lens power (β = -0.41; P lens opacity grade (β = -0.42; P lens power (β = -0.95), lower corneal refractive power (β = -0.76), higher lens thickness (β = 0.30), deeper anterior chamber (β = 0.28), and less marked nuclear lens opacity (β = -0.05). Lens thickness was significantly lower in eyes with greater nuclear opacity. Variations in refractive error in adults aged 50+ years were mostly influenced by variations in axial length and in crystalline lens refractive power, followed by variations in corneal refractive power, and, to a minor degree, by variations in lens thickness and anterior chamber depth.

  6. 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...

  7. A model for the linear stability of the interface between aqueous humor and vitreous substitutes after vitreoretinal surgery

    Science.gov (United States)

    Isakova, Krystyna; Pralits, Jan O.; Repetto, Rodolfo; Romano, Mario R.

    2014-12-01

    We consider the motion of two immiscible viscous fluids induced by periodic oscillations of a flat solid surface along its plane. The interface between the two fluids is parallel to the solid wall; one fluid occupies the region between the wall and the interface and the other extends from the interface to infinity. We study numerically the linear stability of the interface with respect to two-dimensional perturbations using the normal mode analysis and assuming quasi-steady flow conditions. The analysis is motivated by the need of understanding the behavior of vitreous substitutes inserted in the vitreous chamber of the eye after vitrectomy. This is a common surgical procedure adopted to treat retinal detachments, whereby the vitreous humor is removed from the eye and replaced by fluids immiscible with water. Owing to their hydrophobic nature, vitreous substitutes coexist in the vitreous chamber with a certain amount of aqueous humor (the fluid produced in the anterior part of the eye) and, typically, a thin layer of aqueous separates the tamponade fluid from the retina. A common problem with this treatment is that, in some cases, the interface between the two fluids breaks down and this might eventually lead to the generation of an emulsion. It is believed that mechanics plays an important role in this process but the problem remains very poorly understood. We find that instability of the interface is possible in a range of parameters that is relevant for the problem that motivated the present analysis. This suggests that shear instability is likely a possible mechanism triggering the onset of vitreous substitutes-aqueous interface instability.

  8. Investigation of the motion of a viscous fluid in the vitreous cavity induced by eye rotations and implications for drug delivery

    International Nuclear Information System (INIS)

    Bonfiglio, Andrea; Repetto, Rodolfo; Stocchino, Alessandro; Siggers, Jennifer H

    2013-01-01

    Intravitreal drug delivery is a commonly used treatment for several retinal diseases. The objective of this research is to characterize and quantify the role of the vitreous humor motion, induced by saccadic movements, on drug transport processes in the vitreous chamber. A Perspex model of the human vitreous chamber was created, and filled with a purely viscous fluid, representing eyes with a liquefied vitreous humor or those containing viscous tamponade fluids. Periodic movements were applied to the model and the resulting three-dimensional (3D) flow fields were measured. Drug delivery within the vitreous chamber was investigated by calculating particle trajectories using integration over time of the experimental velocity fields. The motion of the vitreous humor generated by saccadic eye movements is intrinsically 3D. Advective mass transport largely overcomes molecular diffusive transport and is significantly anisotropic, leading to a much faster drug dispersion than in the case of stationary vitreous humor. Disregarding the effects of vitreous humor motion due to eye movements when predicting the efficiency of drug delivery treatments leads to significant underestimation of the drug transport coefficients, and this, in turn, will lead to significantly erroneous predictions of the concentration levels on the retina. (paper)

  9. The diffusion dynamics of PEGylated liposomes in the intact vitreous of the ex vivo porcine eye: A fluorescence correlation spectroscopy and biodistribution study

    DEFF Research Database (Denmark)

    Eriksen, Anne Zebitz; Brewer, Jonathan; Andresen, Thomas Lars

    2017-01-01

    correlation spectroscopy (FCS) to determine liposome diffusion coefficients in the intact vitreous (DVit) of ex vivo porcine eyes using a modified Miyake-Apple technique to minimize the disruption of the vitreous fine structure. We chose to investigate whether the zeta potential of polyethylene glycol...

  10. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  11. Concentration of small ring structures in vitreous silica from a first-principles analysis of the Raman spectrum.

    Science.gov (United States)

    Umari, P; Gonze, Xavier; Pasquarello, Alfredo

    2003-01-17

    Using a first-principles approach, we calculate Raman spectra for a model structure of vitreous silica. We develop a perturbational method for calculating the dielectric tensor in an ultrasoft pseudopotential scheme and obtain Raman coupling tensors by finite differences with respect to atomic displacements. For frequencies below 1000 cm(-1), the parallel-polarized Raman spectrum of vitreous silica is dominated by oxygen bending motions, showing a strong sensitivity to the intermediate range structure. By modeling the Raman coupling, we derive estimates for the concentrations of three- and four-membered rings from the experimental intensities of the Raman defect lines.

  12. Predictors of postoperative bleeding after vitrectomy for vitreous hemorrhage in patients with diabetic retinopathy.

    Science.gov (United States)

    Motoda, Saori; Shiraki, Nobuhiko; Ishihara, Takuma; Sakaguchi, Hirokazu; Kabata, Daijiro; Takahara, Mitsuyoshi; Kimura, Takekazu; Kozawa, Junji; Imagawa, Akihisa; Nishida, Kohji; Shintani, Ayumi; Iwahashi, Hiromi; Shimomura, Iichiro

    2017-12-19

    To clarify the association between perioperative variables and postoperative bleeding in pars plana vitrectomy for vitreous hemorrhage in diabetic retinopathy. The present retrospective study enrolled 72 eyes of 64 patients who were admitted to Osaka University Hospital between April 2010 and March 2014, and underwent vitrectomy for vitreous hemorrhage as a result of diabetic retinopathy. Postoperative bleeding developed in 12 eyes. Using binomial logistic regression analysis, we found that the duration of operation was the only significant variable associated with postoperative bleeding within 12 weeks after vitrectomy. Furthermore, Poisson regression analysis identified fasting blood glucose just before vitrectomy, no treatment with antiplatelet drugs and treatment with antihypertensive drugs, as well as duration of operation, to be significantly associated with the frequency of bleeding within 52 weeks after vitrectomy. Long duration of operation can be used to predict bleeding within both 12 and 52 weeks after vitrectomy. In addition, fasting blood glucose just before vitrectomy, no treatment with antiplatelet drugs and treatment with antihypertensive drugs might be risk factors for postoperative bleeding up to 1 year after vitrectomy. © 2017 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

  13. Quantitative analysis of benzodiazepines in vitreous humor by high-performance liquid chromatography

    Science.gov (United States)

    Bazmi, Elham; Behnoush, Behnam; Akhgari, Maryam; Bahmanabadi, Leila

    2016-01-01

    Objective: Benzodiazepines are frequently screened drugs in emergency toxicology, drugs of abuse testing, and in forensic cases. As the variations of benzodiazepines concentrations in biological samples during bleeding, postmortem changes, and redistribution could be biasing forensic medicine examinations, hence selecting a suitable sample and a validated accurate method is essential for the quantitative analysis of these main drug categories. The aim of this study was to develop a valid method for the determination of four benzodiazepines (flurazepam, lorazepam, alprazolam, and diazepam) in vitreous humor using liquid–liquid extraction and high-performance liquid chromatography. Methods: Sample preparation was carried out using liquid–liquid extraction with n-hexane: ethyl acetate and subsequent detection by high-performance liquid chromatography method coupled to diode array detector. This method was applied to quantify benzodiazepines in 21 authentic vitreous humor samples. Linear curve for each drug was obtained within the range of 30–3000 ng/mL with coefficient of correlation higher than 0.99. Results: The limit of detection and quantitation were 30 and 100 ng/mL respectively for four drugs. The method showed an appropriate intra- and inter-day precision (coefficient of variation forensic toxicology laboratory. PMID:27635251

  14. Persistent hyperplastic primary vitreous: imaging evaluation; Persistencia hiperplastica do vitreo primitivo: avaliacao por metodos de imagem

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, Beatriz Mahmud; Teixeira, Kim-Ir-Sen Santos; Figueiredo, Sizenildo da Silva; Nobrega, Bruno Barcelos da [Universidade Federal de Goias, Goiania (Brazil). Hospital das Clinicas. Dept. de Diagnostico por Imagem]. E-mail: biamjacob@hotmail.com

    2003-06-01

    Persistent hyperplastic primary vitreous (PHPV) is a congenital developmental anomaly of the eye that primarily affects premature infants. PHPV results from failure of regression of the embryogenic primary vitreous and hyaloid vasculature, and proliferation of connective tissue. Three types of PHPV may be found: anterior, posterior and a combination of anterior and posterior. The clinical findings include leukocoria (white pupillary reflex) and microphthalmic eye. This anomaly is usually unilateral and unassociated with other systemic findings. The differential diagnosis between PHPV and other ocular diseases may be difficult due to similar features such as leukocoria, detached retina, retinal folds and cataract. Other diseases with similar features include retinoblastoma, isolated congenital cataract, retinopathy of prematurity and pseudo gliomas or leukocorias. Direct visualization of the remnants of the fetal hyaloid vascular system offers the best evidence of PHPV. However, diagnosis using the ophthalmoscope is sometimes impossible because of opaque tissues. In this circumstance an indirect visualization by ultrasound, computed tomography or magnetic resonance imaging may be useful. These imaging methods provide valuable information for the differentiation from other diseases, particularly retinoblastoma. The authors present a review of the literature and an iconographic study of the imaging findings in patients with PHPV. (author)

  15. Crystallization and segregation in vitreous rutile films annealed at high temperature

    International Nuclear Information System (INIS)

    Omari, M.A.; Sorbello, R.S.; Aita, C.R.

    2005-01-01

    Vitreous titania films with rutile short-range order were sputter deposited on unheated fused silica substrates, sequentially annealed at 973 and 1273 K, and examined by Raman microscopy, scanning electron microscopy, and x-ray diffraction. A segregated microstructure developed after the 1273 K anneal. This microstructure consists of supermicron-size craters dispersed in a matrix of submicron rutile crystals. Ti-O short-range order in the craters is characteristic of a mixture of two high pressure phases, m-TiO 2 (monoclinic P2 1 /c space group) and α-TiO 2 (tetragonal Pbcn space group). We calculated that a high average compressive stress parallel to the substrate must be accommodated in the films at 1273 K, caused by the difference in the thermal expansion coefficients of titania and fused silica. The formation of the segregated microstructure is modeled by considering two processes at work at 1273 K to lower a film's internal energy: crystallization and nonuniform stress relief. The Gibbs-Thomson relation shows that small m-TiO 2 crystallites are able to form directly from vitreous TiO 2 at 1273 K. However, the preferred mechanism for forming α-TiO 2 is likely to be by epitaxial growth at crystalline rutile twin boundaries (secondary crystallization). Both phases are denser than crystalline rutile and reduce the average thermal stress in the films

  16. Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers.

    Science.gov (United States)

    Wei, Yong; Su, Yudong; Liu, Chunlan; Nie, Xiangfei; Liu, Zhihai; Zhang, Yu; Zhang, Yonghui

    2017-12-09

    By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR) sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU.

  17. Progressive Outer Retinal Necrosis Combined with Vitreous Hemorrhage in a Patient with Acquired Immunodeficiency Syndrome

    Science.gov (United States)

    You, Yong Sung; Lee, Sung Jin; Lee, Sung Ho; Park, Chang Hyun

    2007-01-01

    Purpose To describe an unusual case of rapidly progressive outer retinal necrosis (PORN) with vitreous hemorrhage in a 41-year-old woman with acquired immunodeficiency syndrome (AIDS), who had retinitis developed from what was probably varicellar-zoster virus combined with cytomegalovirus (CMV) and herpes simplex type 1,2, as proven by the polymerase chain reaction restriction fragment length polymorphism method (PCR-RFLP). Methods This study is a case report detailing clinical follow-up and an aqueous humor test by PCR-RFLP. Results The deep, white retinal lesions coalesced and progressively expanded in a circumferential manner, with sparing of the perivascular retina. However, retinal and vitreous hemorrhages, unusual findings for PORN, could be noted around the optic nerve. Varicellar-zoster virus (VZV), cytomegalovirus (CMV), and herpes simplex types 1,2 (HSV-1,2) were detected in the aqueous humor by PCR. Conclusions PORN has been described as a variant of necrotizing herpetic retinopathy, occurring particularly in patients with AIDS. Although the etiologic agent has been reported to be VZV, concurrent or combined etiologic agents can include HSV-1, HSV-2, and CMV in AIDS patients. Therefore, combined antiviral therapy with acyclovir and ganciclovir could be more reasonable as an initial therapy. PMID:17460434

  18. Integrated Lens Antennas for Multi-Pixel Receivers

    Science.gov (United States)

    Lee, Choonsup; Chattopadhyay, Goutam

    2011-01-01

    Future astrophysics and planetary experiments are expected to require large focal plane arrays with thousands of detectors. Feedhorns have excellent performance, but their mass, size, fabrication challenges, and expense become prohibitive for very large focal plane arrays. Most planar antenna designs produce broad beam patterns, and therefore require additional elements for efficient coupling to the telescope optics, such as substrate lenses or micromachined horns. An antenna array with integrated silicon microlenses that can be fabricated photolithographically effectively addresses these issues. This approach eliminates manual assembly of arrays of lenses and reduces assembly errors and tolerances. Moreover, an antenna array without metallic horns will reduce mass of any planetary instrument significantly. The design has a monolithic array of lens-coupled, leaky-wave antennas operating in the millimeter- and submillimeter-wave frequencies. Electromagnetic simulations show that the electromagnetic fields in such lens-coupled antennas are mostly confined in approximately 12 15 . This means that one needs to design a small-angle sector lens that is much easier to fabricate using standard lithographic techniques, instead of a full hyper-hemispherical lens. Moreover, this small-angle sector lens can be easily integrated with the antennas in an array for multi-pixel imager and receiver implementation. The leaky antenna is designed using double-slot irises and fed with TE10 waveguide mode. The lens implementation starts with a silicon substrate. Photoresist with appropriate thickness (optimized for the lens size) is spun on the substrate and then reflowed to get the desired lens structure. An antenna array integrated with individual lenses for higher directivity and excellent beam profile will go a long way in realizing multi-pixel arrays and imagers. This technology will enable a new generation of compact, low-mass, and highly efficient antenna arrays for use in multi

  19. Two-step technique for posterior optic buttonholing of intraocular lens.

    Science.gov (United States)

    Agarwal, Tushar; Jhanji, Vishal; Singh, Digvijay; Khokhar, Sudarshan

    2014-04-01

    This study aims to describe a two-step surgical technique for placement of a posterior chamber intraocular lens (IOL) in cases with crystalline lens subluxation resulting from non-progressive zonular dialysis. The first stage entails a phacoemulsification with creation of a 4-mm posterior capsular opening using an automated vitrector. The second stage performed 6 weeks later includes an anterior vitrectomy and injection of a foldable three-piece IOL in the sulcus. The haptics of IOL are positioned in the sulcus while the optic is pushed behind the posterior capsular opening therefore "buttonholing" the IOL. Seven eyes of seven patients with posttraumatic zonular dialysis were operated using this technique. Follow-up of all cases revealed a well-centered IOL with good postoperative visual acuity (20/20 to 20/80). Our two-stage surgical technique precludes the insertion of capsular tension ring in cases with non-progressive zonular dialysis. The technique is recommended in the presence of less than or equal to 6 clock hours of zonular dialysis with preexisting posterior capsular tear or herniation of vitreous in the anterior chamber.

  20. Vitreous Detachment

    Science.gov (United States)

    ... NEI Intranet (Employees Only) *PDF files require the free Adobe® Reader® software for viewing. This website is maintained by the NEI Office of Science Communications, Public Liaison, and Education. Technical questions about this website can be addressed ...

  1. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  2. Refractive error, ocular biometry, and lens opalescence in an adult population: the Los Angeles Latino Eye Study.

    Science.gov (United States)

    Shufelt, Chrisandra; Fraser-Bell, Samantha; Ying-Lai, Mei; Torres, Mina; Varma, Rohit

    2005-12-01

    To characterize age- and gender-related differences in refractive error, ocular biometry, and lens opalescence (NOP) in a population-based sample of adult Latinos. Also assessed were the determinants of age-related refractive differences. Participants in the Los Angeles Latino Eye Study (LALES), a population-based study of Latinos aged 40 years and more, underwent an ophthalmic examination, including ultrasonic measurements of axial length (AL), vitreous chamber depth (VCD), anterior chamber depth (ACD), lens thickness (LT), and noncycloplegic automated and subjective refraction. Corneal curvature/power (CP) was measured using an autorefractor. NOP was graded at the slit lamp by an ophthalmologist using the Lens Opacity Classification System II. Age- and gender-related differences were calculated. Multiple regression models were used to identify the determinants of age-related refractive differences. Of the 6357 LALES participants, 5588 phakic individuals with biometric data were included in this analysis. Older individuals had shallower ACDs, thicker lenses, more NOP, and more hyperopia compared to younger individuals (P or = 0.05). Women had significantly shorter AL, shallower ACD and VCD, than did men (P < or = 0.01). The strongest determinants of refractive error were AL (primarily VCD) and CP. NOP was a small but significant determinant of refractive error in older individuals. Age- and gender-related differences in ocular biometric, refractive error, and NOP measurements are present in adult Latinos. While the relative contribution of NOP in determining refractive error is small, it is greater in older persons compared to younger individuals.

  3. Contact lens surface by electron beam

    International Nuclear Information System (INIS)

    Shin, Jung Hyuck; Lee, Suk Ju; Hwang, Kwang Ha; Jeon Jin

    2011-01-01

    Contact lens materials needs good biocompatibility, high refractive index, high optical transparency, high water content etc. Surface treat method by using plasma and radiation can modify the physical and/or chemical properties of the contact lens surface. Radiation technology such as electron beam irradiation can apply to polymerization reaction and enhance the functionality of the polymer.The purpose of this study is to modify of contact lens surface by using Eb irradiation technology. Electron beam was irradiated to the contact lens surface which was synthesized thermal polymerization method and commercial contact lens to modify physical and chemical properties. Ft-IR, XP, UV-vis spectrophotometer, water content, oxygen trans-metastability were used to characterize the surface state, physicochemical, and optical property of the contact lens treated with Eb. The water content and oxygen transmissibility of the contact lens treated with Eb were increased due to increase in the hydrophilic group such as O-C=O and OH group on the contact lens surface which could be produced by possible reaction between carbon and oxygen during the Eb irradiation. All of the lenses showed the high optical transmittance above 90%. In this case of B/Es, TES, Ti contact lens, the optical transmittance decreased about 5% with increasing Eb dose in the wavelength of UV-B region. The contact lens modified by Eb irradiation could improve the physical properties of the contact lens such as water content and oxygen transmissibility

  4. Lens decenter and tilt measurement by interferogram

    Science.gov (United States)

    Hung, Min-Wei; Wu, Wen-Hong; Huang, Kuo-Cheng

    2009-11-01

    For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.

  5. Plasma Lens for Muon and Neutrino Beams

    Science.gov (United States)

    Kahn, Stephen; Korenev, Sergey; Bishai, Mary; Diwan, Milind; Gallardo, Juan; Hershcovitch, Ady; Johnson, Brant

    2008-04-01

    The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-current lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. A plasma lens has additional advantage: larger axial current than horns, minimal neutrino contamination during antineutrino running, and negligible pion absorption or scattering. Results from particle simulations using a plasma lens will be presented.

  6. Lens Coupled Quantum Cascade Laser

    Science.gov (United States)

    Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor)

    2013-01-01

    Terahertz quantum cascade (QC) devices are disclosed that can operate, e.g., in a range of about 1 THz to about 10 THz. In some embodiments, QC lasers are disclosed in which an optical element (e.g., a lens) is coupled to an output facet of the laser's active region to enhance coupling of the lasing radiation from the active region to an external environment. In other embodiments, terahertz amplifier and tunable terahertz QC lasers are disclosed.

  7. Looking beyond the perfect lens

    International Nuclear Information System (INIS)

    Wee, W H; Pendry, J B

    2010-01-01

    The holy grail of imaging is the ability to see through anything. From the conservation of energy, we can easily see that to see through a lossy material would require lenses with gain. The aim of this paper therefore is to propose a simple scheme by which we can construct a general perfect lens, with gain-one that can restore both the phases and amplitudes of near and far fields.

  8. Verification of eye lens dose in IMRT by MOSFET measurement.

    Science.gov (United States)

    Wang, Xuetao; Li, Guangjun; Zhao, Jianling; Song, Ying; Xiao, Jianghong; Bai, Sen

    2018-04-17

    The eye lens is recognized as one of the most radiosensitive structures in the human body. The widespread use of intensity-modulated radiotherapy (IMRT) complicates dose verification and necessitates high standards of dose computation. The purpose of this work was to assess the computed dose accuracy of eye lens through measurements using a metal-oxide-semiconductor field-effect transistor (MOSFET) dosimetry system. Sixteen clinical IMRT plans of head and neck patients were copied to an anthropomorphic head phantom. Measurements were performed using the MOSFET dosimetry system based on the head phantom. Two MOSFET detectors were imbedded in the eyes of the head phantom as the left and the right lens, covered by approximately 5-mm-thick paraffin wax. The measurement results were compared with the calculated values with a dose grid size of 1 mm. Sixteen IMRT plans were delivered, and 32 measured lens doses were obtained for analysis. The MOSFET dosimetry system can be used to verify the lens dose, and our measurements showed that the treatment planning system used in our clinic can provide adequate dose assessment in eye lenses. The average discrepancy between measurement and calculation was 6.7 ± 3.4%, and the largest discrepancy was 14.3%, which met the acceptability criterion set by the American Association of Physicists in Medicine Task Group 53 for external beam calculation for multileaf collimator-shaped fields in buildup regions. Copyright © 2018 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  9. Glycation precedes lens crystallin aggregation

    International Nuclear Information System (INIS)

    Swamy, M.S.; Perry, R.E.; Abraham, E.C.

    1987-01-01

    Non-enzymatic glycosylation (glycation) seems to have the potential to alter the structure of crystallins and make them susceptible to thiol oxidation leading to disulfide-linked high molecular weight (HMW) aggregate formation. They used streptozotocin diabetic rats during precataract and cataract stages and long-term cell-free glycation of bovine lens crystallins to study the relationship between glycation and lens crystallin aggregation. HMW aggregates and other protein components of the water-soluble (WS) and urea-soluble (US) fractions were separated by molecular sieve high performance liquid chromatography. Glycation was estimated by both [ 3 H]NaBH 4 reduction and phenylboronate agarose affinity chromatography. Levels of total glycated protein (GP) in the US fractions were about 2-fold higher than in the WS fractions and there was a linear increase in GP in both WS and US fractions. This increase was parallelled by a corresponding increase in HMW aggregates. Total GP extracted by the affinity method from the US fraction showed a predominance of HMW aggregates and vice versa. Cell-free glycation studies with bovine crystallins confirmed the results of the animals studies. Increasing glycation caused a corresponding increase in protein insolubilization and the insoluble fraction thus formed also contained more glycated protein. It appears that lens protein glycation, HMW aggregate formation, and protein insolubilization are interrelated

  10. Electron exchange between neutral and ionized impurity iron centers in vitreous arsenic selenide

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, A. V. [Herzen State Pedagogical University of Russia (Russian Federation); Terukov, E. I. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Egorova, A. Yu. [St.-Petersburg Mining University (Russian Federation); Kiselev, V. S.; Seregin, P. P., E-mail: ppseregin@mail.ru [Herzen State Pedagogical University of Russia (Russian Federation)

    2017-04-15

    Impurity iron atoms in vitreous arsenic-selenide As{sub 2}Se{sub 3} films modified by iron form one-electron donor centers with an ionization energy of 0.24 (3) eV (the energy is counted from the conduction-band bottom). The Fermi level is shifted with an increase in the iron concentration from the mid-gap to the donorlevel position of iron due to the filling of one-electron states of the acceptor type lying below the Fermi level. At an iron concentration of ≥3 at %, the electron-exchange process is observed between neutral and ionized iron centers resulting in a change both in the electron density and in the tensor of the electric-field gradient at iron-atom nuclei with increasing temperature above 350 K.

  11. Valence band structure of binary chalcogenide vitreous semiconductors by high-resolution XPS

    International Nuclear Information System (INIS)

    Kozyukhin, S.; Golovchak, R.; Kovalskiy, A.; Shpotyuk, O.; Jain, H.

    2011-01-01

    High-resolution X-ray photoelectron spectroscopy (XPS) is used to study regularities in the formation of valence band electronic structure in binary As x Se 100−x , As x S 100−x , Ge x Se 100−x and Ge x S 100−x chalcogenide vitreous semiconductors. It is shown that the highest occupied energetic states in the valence band of these materials are formed by lone pair electrons of chalcogen atoms, which play dominant role in the formation of valence band electronic structure of chalcogen-rich glasses. A well-expressed contribution from chalcogen bonding p electrons and more deep s orbitals are also recorded in the experimental valence band XPS spectra. Compositional dependences of the observed bands are qualitatively analyzed from structural and compositional points of view.

  12. Valence band structure of binary chalcogenide vitreous semiconductors by high-resolution XPS

    Energy Technology Data Exchange (ETDEWEB)

    Kozyukhin, S., E-mail: sergkoz@igic.ras.ru [Russian Academy of Science, Institute of General and Inorganic Chemistry (Russian Federation); Golovchak, R. [Lviv Scientific Research Institute of Materials of SRC ' Carat' (Ukraine); Kovalskiy, A. [Lehigh University, Department of Materials Science and Engineering (United States); Shpotyuk, O. [Lviv Scientific Research Institute of Materials of SRC ' Carat' (Ukraine); Jain, H. [Lehigh University, Department of Materials Science and Engineering (United States)

    2011-04-15

    High-resolution X-ray photoelectron spectroscopy (XPS) is used to study regularities in the formation of valence band electronic structure in binary As{sub x}Se{sub 100-x}, As{sub x}S{sub 100-x}, Ge{sub x}Se{sub 100-x} and Ge{sub x}S{sub 100-x} chalcogenide vitreous semiconductors. It is shown that the highest occupied energetic states in the valence band of these materials are formed by lone pair electrons of chalcogen atoms, which play dominant role in the formation of valence band electronic structure of chalcogen-rich glasses. A well-expressed contribution from chalcogen bonding p electrons and more deep s orbitals are also recorded in the experimental valence band XPS spectra. Compositional dependences of the observed bands are qualitatively analyzed from structural and compositional points of view.

  13. Evaluation of hyaluronan from different sources: Streptococcus zooepidemicus, rooster comb, bovine vitreous, and human umbilical cord.

    Science.gov (United States)

    Shiedlin, Aviva; Bigelow, Russell; Christopher, William; Arbabi, Saman; Yang, Laura; Maier, Ronald V; Wainwright, Norman; Childs, Alice; Miller, Robert J

    2004-01-01

    Sodium hyaluronate (HA) is widely distributed in extracellular matrixes and can play a role in orchestrating cell function. Consequently, many investigators have looked at the effect of exogenous HA on cell behavior in vitro. HA can be isolated from several sources (e.g., bacterial, rooster comb, umbilical cord) and therefore can possess diverse impurities. This current study compares the measured impurities and the differences in biological activity between HA preparations from these sources. It was demonstrated that nucleic acid and protein content was highest in human umbilical cord and bovine vitreous HA and was low in bacterial and rooster comb HA. Macrophages exposed to human umbilical cord HA produced significantly higher amounts of TNF-alpha relative to control or bacterial-derived HA. These results indicate that the source of HA should be considered due to differences in the amounts and types of contaminants that could lead to widely different behaviors in vitro and in vivo.

  14. Preparation, electrochemical characterization and charge-discharge of reticulated vitreous carbon/polyaniline composite electrodes

    International Nuclear Information System (INIS)

    Dalmolin, Carla; Biaggio, Sonia R.; Rocha-Filho, Romeu C.; Bocchi, Nerilso

    2009-01-01

    Polyaniline was electrodeposited onto reticulated vitreous carbon - RVC - in order to obtain a tridimensional composite electrode. Three variations of these electrodes were analysed: a small-anion-doped polyaniline (RVC/Pani), a polyanion-doped polyaniline (RVC/PaniPSS) and a bi-layer type formed by an inner layer of the first electrode and an outer layer of the second one (RVC/Pani/PaniPSS). These composites were characterized by cyclic voltammetry, scanning electronic microscopy and electrochemical impedance spectroscopy. Photomicrographies, voltammetric profiles and impedance data pointed to different morphological and electrochemical characteristics for polyaniline doped with small or large anions, and a mixed behavior for the bi-layer electrodes. Charge-discharge tests for these tridimensional (3D) electrodes, employed as the cathode in lithium batteries, indicated better performance for the RVC/Pani electrode. These RVC composites presented higher specific capacities when compared with those obtained for Pani deposited onto bidimensional substrates.

  15. Changes in the thermoelectric response of vitreous carbon due to the irradiation by γ-rays

    Science.gov (United States)

    Culebras, M.; Madroñero, A.; Mota, C.; Gómez, C. M.; Amo, Jose M.; Cantarero, A.

    2014-07-01

    In order to study variations in the thermoelectric properties, some commercial glassy carbon samples were subjected to a sequence of steps consisting of a combination of irradiation with γ-rays produced by radioisotopes 60Co, and hydrogen adsorption when the samples were put in an over pressured atmosphere of this gas. With this procedure it was possible to observe that the irradiation decreases the electrical conductivity of glassy carbon samples and the hydrogenation changes the sign of Seebeck coefficient. The material initially is an n-type semiconductor, but with hydrogenation changes to p-type semiconductor. X-ray diffraction analysis showed that the hydrogenated vitreous carbon is more amorphous than the pristine material and the γ-rays irradiation produces changes in the crystallite size and shape.

  16. Electrochemical reversibility of reticulated vitreous carbon electrodes heat treated at different carbonization temperatures

    Directory of Open Access Journals (Sweden)

    Emerson Sarmento Gonçalves

    2006-06-01

    Full Text Available Electrochemical response of ferri/ferrocyanide redox couple is discussed for a system that uses reticulated vitreous carbon (RVC three dimensional electrodes prepared at five different Heat Treatment Temperatures (HTT in the range of 700 °C to 1100 °C. Electrical resistivity, scanning electron microscopy and X ray Diffraction analyses were performed for all prepared samples. It was observed that the HTT increasing promotes an electrical conductivity increasing while the Bragg distance d002 decreases. The correlation between reversibility behavior of ferri/ferrocyanide redox couple and both surface morphology and chemical properties of the RVC electrodes demonstrated a strong dependence on the HTT used to prepare the RVC.

  17. Defects in electron irradiated vitreous SiO2 probed by positron annihiliation

    International Nuclear Information System (INIS)

    Uedono, Akira; Tanigawa, Shoichiro; Kawano, Takao; Itoh, Hisayoshi

    1994-01-01

    Defects in 3 MeV electron irradiated vitreous SiO 2 (v-SiO 2 ) were probed by the positron annihilation technique. For unirradiated v-SiO 2 specimens, almost all positrons were found to annihilate from positronium (Ps) states. This high formation probability of Ps was attributed to the trapping of positrons by open-space defects. The formation probability of Ps was decreased by the electron irradiation. The observed inhibition of the Ps formation was attributed to the trapping of positrons by point defects introduced and/or activated by the irradiation. From measurements of the lifetime distribution of Ps, it was found that, by the electron irradiation, the mean size of open-space defects was decreased and the size distribution of such defects was broadened. (Author)

  18. Defects in electron irradiated vitreous SiO[sub 2] probed by positron annihiliation

    Energy Technology Data Exchange (ETDEWEB)

    Uedono, Akira; Tanigawa, Shoichiro (Tsukuba Univ., Ibaraki (Japan). Inst. of Materials Science); Kawano, Takao (Tsukuba Univ., Ibaraki (Japan). Radioisotope Centre); Itoh, Hisayoshi (Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment)

    1994-10-10

    Defects in 3 MeV electron irradiated vitreous SiO[sub 2] (v-SiO[sub 2]) were probed by the positron annihilation technique. For unirradiated v-SiO[sub 2] specimens, almost all positrons were found to annihilate from positronium (Ps) states. This high formation probability of Ps was attributed to the trapping of positrons by open-space defects. The formation probability of Ps was decreased by the electron irradiation. The observed inhibition of the Ps formation was attributed to the trapping of positrons by point defects introduced and/or activated by the irradiation. From measurements of the lifetime distribution of Ps, it was found that, by the electron irradiation, the mean size of open-space defects was decreased and the size distribution of such defects was broadened. (Author).

  19. Vitreous membranes used in the biogas purification; Membranas vitreas empleadas en la purificacion de biogas

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Viera, L.; Rodriguez Munoz, S.; Fernandez Santana, E.; Martines Ramirez, Y.; Crespo Artigas, A.; Viera Gallardo, Y.

    2016-05-01

    In the present work 10 vitreous membranes with different masses of zinc oxide (ZnO(s)) and particle diameters charcoal (DPC) are used in the purification of biogas. The porosity and tortuosity of the membranes is obtained, showing the variation with respect to the composition thereof. From these structural features specific flow of H{sub 2}S(g) is obtained which is transferred using the Fick's diffusion equation in the membranes and its value increases with increasing mass of ZnO(s). By X-ray diffraction membrane made with 3.16 g of ZnO(s) forming zinc sulfide it is shown, so we can say that the removal of H{sub 2}S(g) occurs by a process of absorption with chemical reaction in the membranes. (Author)

  20. Preservation of high resolution protein structure by cryo-electron microscopy of vitreous sections

    International Nuclear Information System (INIS)

    Sader, Kasim; Studer, Daniel; Zuber, Benoit; Gnaegi, Helmut; Trinick, John

    2009-01-01

    We have quantitated the degree of structural preservation in cryo-sections of a vitrified biological specimen. Previous studies have used sections of periodic specimens to assess the resolution present, but preservation before sectioning was not assessed and so the damage due particularly to cutting was not clear. In this study large single crystals of lysozyme were vitrified and from these X-ray diffraction patterns extending to better than 2.1 A were obtained. The crystals were high pressure frozen in 30% dextran, and cryo-sectioned using a diamond knife. In the best case, preservation to a resolution of 7.9 A was shown by electron diffraction, the first observation of sub-nanometre structural preservation in a vitreous section.

  1. Proposal of the system for the biogas purification using vitreous and natural zeolite membranes

    International Nuclear Information System (INIS)

    Ortega Viera, Lianys; Fernández SantanI, Elina; Alfonso Martínez, Félix Enrique; Aguiar RoqueI, Yania; Rodríguez Muñoz, Susana

    2017-01-01

    One way to reduce the effects of climate change is to replace fossil fuels with renewable energy such as biogas, but the amount of hydrogen sulphide in it represents an impediment to its use, because of its negative impacts on human health, materials of construction and the environment, being essential its reduction or elimination. For this reason, it was defined as aim to propose an effective method for the purification of biogas using membranes constructed from vitreous waste materials and natural cuban zeolite. This treatment requires four membranes with their supports and eight valves and could be used by small farmers for the purification of 1.4 m 3 of biogas per day, an amount necessary for the cooking of three meals of a family of five people, being the cost of the biogas purification process equal to 0.06%/m 3 . (author)

  2. Leber congenital amaurosis associated with optic disk neovascularization and vitreous hemorrhage.

    Science.gov (United States)

    Kurz, Daryl; Ciulla, Thomas A

    2003-05-01

    To report an unusual case of optic disk neovascularization and vitreous hemorrhage associated with Leber congenital amaurosis (LCA). Interventional case report. A 16-year-old Caucasian girl with a history of LCA presented with decreased vision in her left eye, diffuse retinal pigmentary abnormalities characteristic of LCA, and hemorrhage over the left optic disk and macula. Six months of follow-up revealed optic disk neovascularization. A small amount of neovascularization was noted in the right eye at 6 months. An extensive systemic evaluation indicated no other cause for the neovascularization. Panretinal photocoagulation was performed in both eyes, and subsequently the neovascularization regressed. Leber congenital amaurosis like retinitis pigmentosa, can rarely be associated with neovascularization of the disk, which is amenable to treatment with peripheral photocoagulation if it does not spontaneously regress.

  3. Development of highly open polyhedral networks from vitreous carbon for orthopaedic applications

    Science.gov (United States)

    Güiza-Argüello, V.; Bayona-Becerra, M.; Cruz-Orellana, S.; Córdoba-Tuta, E.

    2017-01-01

    Highly open polyhedral networks were fabricated using an economical and environmentally friendly template route. Recycled cellulose foams were impregnated with a sucrose resin and then pyrolyzed in order to produce reticulated vitreous carbon foams with morphological features that closely resemble trabecular bone. Also, cell sizes ~1mm were achieved, a trait that will allow the mechanical reinforcement of such scaffolds using a biomaterial coating without compromising the pore size that favors osteoblast cell infiltration and growth (200-500µm). Moreover, initial studies showed that carbonization conditions have an effect on the mechanical properties of the synthesized foams and, therefore, such process parameters could be further evaluated towards the enhancement of the mechanical resistance of the scaffolds. The materials developed here are visualized as the porous component of a synthetic bone graft with features that could help overcome the current limitations associated with the medical treatments used for bone defect repair.

  4. The Effect of the Crystalline Lens on Central Vault After Implantable Collamer Lens Implantation.

    Science.gov (United States)

    Qi, Meng-Ying; Chen, Qian; Zeng, Qing-Yan

    2017-08-01

    To identify associations between crystalline lens-related factors and central vault after Implantable Collamer Lens (ICL) (Staar Surgical, Monrovia, CA) implantation. This retrospective clinical study included 320 eyes from 186 patients who underwent ICL implantation surgery. At 1 year after surgery, the central vault was measured using anterior segment optical coherence tomography. Preoperative anterior chamber depth, lens thickness, lens position (lens position = anterior chamber depth + 1/2 lens thickness), and vault were analyzed to investigate the effects of lens-related factors on postoperative vault. The mean vault was 513 ± 215 µm at 1 year after surgery. Vault was positively correlated with preoperative anterior chamber depth (r = 0.495, P lens position (r = 0.371, P lens thickness (r = -0.262, P lens position than eyes in the other two vault groups (which had vaults ≥ 250 µm) (P lens position less than 5.1 mm had greatly reduced vaults (P lens could have an important influence on postoperative vault. Eyes with a shallower anterior chamber and a forward lens position will have lower vaults. [J Refract Surg. 2017;33(8):519-523.]. Copyright 2017, SLACK Incorporated.

  5. Two-Channel SPR Sensor Combined Application of Polymer- and Vitreous-Clad Optic Fibers

    Directory of Open Access Journals (Sweden)

    Yong Wei

    2017-12-01

    Full Text Available By combining a polymer-clad optic fiber and a vitreous-clad optic fiber, we proposed and fabricated a novel optic fiber surface plasmon resonance (SPR sensor to conduct two-channel sensing at the same detection area. The traditional optic fiber SPR sensor has many disadvantages; for example, removing the cladding requires corrosion, operating it is dangerous, adjusting the dynamic response range is hard, and producing different resonance wavelengths in the sensing area to realize a multi-channel measurement is difficult. Therefore, in this paper, we skillfully used bare fiber grinding technology and reverse symmetry welding technology to remove the cladding in a multi-mode fiber and expose the evanescent field. On the basis of investigating the effect of the grinding angle on the dynamic range change of the SPR resonance valley wavelength and sensitivity, we combined polymer-clad fiber and vitreous-clad fiber by a smart design structure to realize at a single point a two-channel measurement fiber SPR sensor. In this paper, we obtained a beautiful spectral curve from a multi-mode fiber two-channel SPR sensor. In the detection range of the refractive rate between 1.333 RIU and 1.385 RIU, the resonance valley wavelength of channel Ⅰ shifted from 622 nm to 724 nm with a mean average sensitivity of 1961 nm/RIU and the resonance valley wavelength of channel Ⅱ shifted from 741 nm to 976 nm with a mean average sensitivity of 4519 nm/RIU.

  6. Risk factors for posterior vitreous detachment: a case-control study.

    Science.gov (United States)

    Chuo, Jean Y; Lee, Tracy Y Y; Hollands, Hussein; Morris, Andrew H; Reyes, Romina C; Rossiter, Jonathan D; Meredith, Sarah P; Maberley, David A L

    2006-12-01

    To identify possible risk factors for the development of posterior vitreous detachment (PVD). Retrospective case-control study. A total of 138 cases with PVD and 114 age-matched controls were accrued from two different sites. Demographic, medical, ocular, and lifestyle data were obtained through chart review, questionnaires, and clinical examination. A 108-item semiquantitative food frequency questionnaire was also used to estimate macro- and micronutrient intake. Univariate and multivariate regression analyses were employed to identify variables significantly associated with the main outcome measure of PVD. Subgroup analysis of gender-specific variables was performed. Among all patients, multivariate regression analysis demonstrated female gender (odds ratio [OR] = 2.01, P = .016), myopic refraction (OR = 4.32, P < .0005), and higher intake of vitamin B6 (OR = 2.61, P = .001) to be associated with PVD after controlling for age. In the subgroup analysis of women, menopause (OR = 18.2, P < .0005), myopic refraction (OR = 3.42, P = .01), and higher intake of vitamin B6 (OR = 3.92, P = .005) were associated with PVD. Specifically, there was a significant association between vitamin B6 and PVD amongst premenopausal women but not amongst postmenopausal women. An association between PVD and menopause has not been documented previously. We suspect that high estrogen levels seen in premenopausal women may be protective against PVD and that hormonal changes associated with menopause may lead to changes in the vitreous, predisposing to PVD. Higher levels of intake of vitamin B6 were also associated with the development of PVD in premenopausal women possibly through an anti-estrogen effect. These findings should be investigated further with prospective studies.

  7. The current status of eye lens dose measurement in interventional cardiology personnel in Thailand.

    Science.gov (United States)

    Krisanachinda, Anchali; Srimahachota, Suphot; Matsubara, Kosuke

    2017-06-01

    Workers involved in interventional cardiology procedures receive high eye lens doses if radiation protection tools are not properly utilized. Currently, there is no suitable method for routine measurement of eye dose. In Thailand, the eye lens equivalent doses in terms of Hp(3) of the interventional cardiologists, nurses, and radiographers participating in interventional cardiology procedures have been measured at 12 centers since 2015 in the pilot study. The optically stimulated luminescence (OSL) dosimeter was used for measurement of the occupational exposure and the eye lens dose of 42 interventional cardiology personnel at King Chulalongkorn Memorial Hospital as one of the pilot centers. For all personnel, it is recommended that a first In Light OSL badge is placed at waist level and under the lead apron for determination of Hp(10); a second badge is placed at the collar for determination of Hp(0.07) and estimation of Hp(3). Nano Dots OSL dosimeter has been used as an eye lens dosimeter for 16 interventional cardiology personnel, both with and without lead-glass eyewear. The mean effective dose at the body, equivalent dose at the collar, and estimated eye lens dose were 0.801, 5.88, and 5.70 mSv per year, respectively. The mean eye lens dose measured by the Nano Dots dosimeter was 8.059 mSv per year on the left eye and 3.552 mSv per year on the right eye. Two of 16 interventional cardiologists received annual eye lens doses on the left side without lead glass that were higher than 20 mSv per year, the new eye lens dose limit as recommended by ICRP with the risk of eye lens opacity and cataract.

  8. Primary intraocular lens implantation for penetrating lens trauma in Africa.

    Science.gov (United States)

    Bowman, R J; Yorston, D; Wood, M; Gilbert, C; Foster, A

    1998-09-01

    This study aimed to audit the surgical strategy of primary posterior chamber intraocular lens implantation for cases of recent penetrating trauma involving the lens in an African population. Retrospective, noncomparative case series. Seventy-two cases are reported, including all patients who underwent primary intraocular lens implantation for traumatic cataract extraction performed within 1 month of injury between 1988 and 1996. Demographic characteristics and follow-up attendance rates are analyzed. Surgical technique and the occurrence of intraoperative and postoperative complications are reported. Visual outcomes are reported with detailed analysis for cases of poor visual outcome. Mean age was 14.3 years (standard deviation = 11.1), 57 (79%) were male and 15 (21%) were female (chi-square = 23.66, P capsule had been breached by the trauma in 27 (38%) cases, and 15 of these required anterior vitrectomy. Capsular fixation of the implant was achieved in 49% of patients, the remainder having sulcus fixation. Intraoperative rupture of the posterior capsule occurred in four cases. The only common postoperative complication was acute fibrinous anterior uveitis, which occurred in 29 (40%) patients, and 32% of patients followed up for at least 6 months required secondary posterior capsulotomy. This was more common in younger patients (chi-square = 4.2, P < 0.05). Corrected postoperative visual acuities were available for 51 patients, of which 71% achieved 20/60 or better visual acuity. Patients 6 years of age or younger were less likely to achieve 20/60 (chi-square = 6.61, P = 0.01). This surgical strategy has proved successful, producing good visual results and causing no sight-threatening complications. Primary posterior capsulotomy may be appropriate for younger patients.

  9. DISSECTING THE GRAVITATIONAL LENS B1608+656. I. LENS POTENTIAL RECONSTRUCTION

    NARCIS (Netherlands)

    Suyu, S. H.; Marshall, P. J.; Blandford, R. D.; Fassnacht, C. D.; Koopmans, L. V. E.; McKean, J. P.; Treu, T.

    2009-01-01

    Strong gravitational lensing is a powerful technique for probing galaxy mass distributions and for measuring cosmological parameters. Lens systems with extended source-intensity distributions are particularly useful for this purpose since they provide additional constraints on the lens potential (

  10. Multiple methods of surgical treatment combined with primary IOL implantation on traumatic lens subluxation/dislocation in patients with secondary glaucoma

    Directory of Open Access Journals (Sweden)

    Rui Wang

    2014-04-01

    Full Text Available AIM:To describe clinical findings and complications from cases of traumatic lens subluxation/dislocation in patients with secondary glaucoma, and discuss the multiple treating methods of operation combined with primary intraocular lens (IOL implantation.METHODS:Non-comparative retrospective observational case series. Participants:30 cases (30 eyes of lens subluxation/dislocation in patients with secondary glaucoma were investigated which accepted the surgical treatment by author in the Ophthalmology of Xi''an No.4 Hospital from 2007 to 2011. According to the different situations of lens subluxation/dislocation, various surgical procedures were performed such as crystalline lens phacoemulsification, crystalline lens phacoemulsification combined anterior vitrectomy, intracapsular cataract extraction combined anterior vitrectomy, lensectomy combined anterior vitrectomy though peripheral transparent cornea incision, pars plana lensectomy combined pars plana vitrectomy, and intravitreal cavity crystalline lens phacofragmentation combined pars plana vitrectomy. And whether to implement trabeculectomy depended on the different situations of secondary glaucoma. The posterior chamber intraocular lenses (PC-IOLs were implanted in the capsular-bag or trassclerally sutured in the sulus decided by whether the capsular were present. Main outcome measures:visual acuity, intraocular pressure, the situation of intraocular lens and complications after the operations.RESULTS: The follow-up time was 11-36mo (21.4±7.13. Postoperative visual acuity of all eyes were improved; 28 cases maintained IOP below 21 mm Hg; 2 cases had slightly IOL subluxation, 4 cases had slightly tilted lens optical area; 1 case had postoperative choroidal detachment; 4 cases had postoperative corneal edema more than 1wk, but eventually recovered transparent; 2 cases had mild postoperative vitreous hemorrhage, and absorbed 4wk later. There was no postoperative retinal detachment, IOL

  11. Role of Aquaporin 0 in lens biomechanics

    International Nuclear Information System (INIS)

    Sindhu Kumari, S.; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G.; Menon, Anil G.; Mathias, Richard T.; Varadaraj, Kulandaiappan

    2015-01-01

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5 −/− ), AQP0 KO (heterozygous KO: AQP0 +/− ; homozygous KO: AQP0 −/− ; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0 +/− lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to

  12. Algorithm design of liquid lens inspection system

    Science.gov (United States)

    Hsieh, Lu-Lin; Wang, Chun-Chieh

    2008-08-01

    In mobile lens domain, the glass lens is often to be applied in high-resolution requirement situation; but the glass zoom lens needs to be collocated with movable machinery and voice-coil motor, which usually arises some space limits in minimum design. In high level molding component technology development, the appearance of liquid lens has become the focus of mobile phone and digital camera companies. The liquid lens sets with solid optical lens and driving circuit has replaced the original components. As a result, the volume requirement is decreased to merely 50% of the original design. Besides, with the high focus adjusting speed, low energy requirement, high durability, and low-cost manufacturing process, the liquid lens shows advantages in the competitive market. In the past, authors only need to inspect the scrape defect made by external force for the glass lens. As to the liquid lens, authors need to inspect the state of four different structural layers due to the different design and structure. In this paper, authors apply machine vision and digital image processing technology to administer inspections in the particular layer according to the needs of users. According to our experiment results, the algorithm proposed can automatically delete non-focus background, extract the region of interest, find out and analyze the defects efficiently in the particular layer. In the future, authors will combine the algorithm of the system with automatic-focus technology to implement the inside inspection based on the product inspective demands.

  13. Freeform lens design for LED collimating illumination.

    Science.gov (United States)

    Chen, Jin-Jia; Wang, Te-Yuan; Huang, Kuang-Lung; Liu, Te-Shu; Tsai, Ming-Da; Lin, Chin-Tang

    2012-05-07

    We present a simple freeform lens design method for an application to LED collimating illumination. The method is derived from a basic geometric-optics analysis and construction approach. By using this method, a highly collimating lens with LED chip size of 1.0 mm × 1.0 mm and optical simulation efficiency of 86.5% under a view angle of ± 5 deg is constructed. To verify the practical performance of the lens, a prototype of the collimator lens is also made, and an optical efficiency of 90.3% with a beam angle of 4.75 deg is measured.

  14. Principles for the design and calibration of radiation protection dosemeters for operational and protection quantities for eye lens dosimetry

    International Nuclear Information System (INIS)

    Bordy, J. M.; Gualdrini, G.; Daures, J.; Mariotti, F.

    2011-01-01

    The work package two of the ORAMED project-Collaborative Project (2008-2011) supported by the European Commission within its seventh Framework Programme-is devoted to the study of the eye lens dosimetry. A first approach is to implement the use of H p (3) by providing new sets of conversion coefficients and well suited calibration and type test procedures. This approach is presented in other papers in the proceedings of this conference. Taking into account that the eye lens is an organ close to the surface of the body, another approach would be to directly estimate the absorbed dose to the eye lens, D lens,est through a special calibration procedure although this quantity is not directly measurable. This paper is a methodological paper that tries to identify the critical aspects of a dosimetry in terms of D lens . (authors)

  15. Changes in lens stiffness due to capsular opacification in accommodative lens refilling

    NARCIS (Netherlands)

    Nibourg, Lisanne M.; Sharma, Prashant K.; van Kooten, Theo G.; Koopmans, Steven A.

    Accommodation may be restored to presbyopic lenses by refilling the lens capsular bag with a soft polymer. After this accommodative lens refilling prevention of capsular opacification is a requirement, since capsular opacification leads to a decreased clarity of the refilled lens. It has been

  16. Exchange of tears under a contact lens is driven by distortions of the contact lens.

    Science.gov (United States)

    Maki, Kara L; Ross, David S

    2014-12-01

    We studied the flow of the post-lens tear film under a soft contact lens to understand how the design parameters of contact lenses can affect ocular health. When a soft contact lens is inserted, the blinking eyelid causes the lens to stretch in order to conform to the shape of the eye. The deformed contact lens acts to assume its un-deformed shape and thus generates a suction pressure in the post-lens tear film. In consequence, the post-lens tear fluid moves; it responds to the suction pressure. The suction pressure may draw in fresh fluid from the edge of the lens, or it may eject fluid there, as the lens reassumes its un-deformed shape. In this article, we develop a mathematical model of the flow of the post-lens tear fluid in response to the mechanical suction pressure of a deformed contact lens. We predict the amount of exchange of fluid exchange under a contact lens and we explore the influence of the eye's shape on the rate of exchange of fluid. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  17. A new model for the estimation of time of death from vitreous potassium levels corrected for age and temperature.

    Science.gov (United States)

    Zilg, B; Bernard, S; Alkass, K; Berg, S; Druid, H

    2015-09-01

    Analysis of potassium concentration in the vitreous fluid of the eye is frequently used by forensic pathologists to estimate the postmortem interval (PMI), particularly when other methods commonly used in the early phase of an investigation can no longer be applied. The postmortem rise in vitreous potassium has been recognized for several decades and is readily explained by a diffusion of potassium from surrounding cells into the vitreous fluid. However, there is no consensus regarding the mathematical equation that best describes this increase. The existing models assume a linear increase, but different slopes and starting points have been proposed. In this study, vitreous potassium levels, and a number of factors that may influence these levels, were examined in 462 cases with known postmortem intervals that ranged from 2h to 17 days. We found that the postmortem rise in potassium followed a non-linear curve and that decedent age and ambient temperature influenced the variability by 16% and 5%, respectively. A long duration of agony and a high alcohol level at the time of death contributed less than 1% variability, and evaluation of additional possible factors revealed no detectable impact on the rise of vitreous potassium. Two equations were subsequently generated, one that represents the best fit of the potassium concentrations alone, and a second that represents potassium concentrations with correction for decedent age and/or ambient temperature. The former was associated with narrow confidence intervals in the early postmortem phase, but the intervals gradually increased with longer PMIs. For the latter equation, the confidence intervals were reduced at all PMIs. Therefore, the model that best describes the observed postmortem rise in vitreous potassium levels includes potassium concentration, decedent age, and ambient temperature. Furthermore, the precision of these equations, particularly for long PMIs, is expected to gradually improve by adjusting the

  18. Upregulation of Mir-21 Levels in the Vitreous Humor Is Associated with Development of Proliferative Vitreoretinal Disease.

    Directory of Open Access Journals (Sweden)

    Ayumi Usui-Ouchi

    Full Text Available MicroRNAs (miRNAs are small noncoding RNAs that regulate gene expression by post-transcriptional inhibition of mRNA translation. Dysregulation of miRNAs, including circulating miRNAs, has been reported to play an important role in the development of various diseases, including fibrotic diseases. Aberrant expression of miRNAs in the vitreous humor of vitreoretinal diseased eyes has been reported. However, the expression pattern of miRNAs present in the vitreous humor of proliferative vitreoretinal disease (PVD patients, including proliferative diabetic retinopathy (PDR, and proliferative vitreoretinopathy (PVR, remains unknown. To investigate the factors important for the development of PVD, we characterized the miRNAs present in the vitreous humor of PVD patients and analyzed the expression profiles of 377 miRNAs using quantitative polymerase chain reaction-based miRNA arrays. The expression of a specific subset of miRNAs, previously reported to be associated with the development of angiogenesis and fibrosis, was significantly altered in the vitreous of PVD patients. Among these miRNAs, we identified miR-21 as a candidate fibrotic miRNA with an important role in the pathogenesis of PVD. Increased miR-21 levels in the vitreous were associated with retinal fibrosis, including PVR and PDR. Because epithelial-mesenchymal transition (EMT of retinal pigment epithelial cells (RPECs plays a critical role in retinal fibrosis, the expression of miR-21 in human RPECs was determined. Its expression in RPECs was induced by transforming growth factor-β, a key growth factor involved in fibrogenesis, and was enhanced by high glucose culture conditions, suggesting that miR-21 expression positively correlates with disease progression. Gain- and loss-of-function studies revealed that miR-21 promoted cell proliferation and migration of ARPE-19 cells without affecting EMT-related gene expression. Together, our studies have identified miR-21 as a potential disease

  19. Lens design and local minima

    International Nuclear Information System (INIS)

    Brixner, B.

    1981-01-01

    The widespread belief that local minima exist in the least squares lens-design error function is not confirmed by the Los Alamos Scientific Laboratory (LASL) optimization program. LASL finds the optimum-mimimum region, which is characterized by small parameter gradients of similar size, small performance improvement per iteration, and many designs that give similar performance. Local minima and unique prescriptions have not been found in many-parameter problems. The reason for these absences is that image errors caused by a change in one parameter can be compensated by changes in the remaining parameters. False local minima have been found, and four cases are discussed

  20. Laser device and method

    International Nuclear Information System (INIS)

    Myers, J.D.

    1986-01-01

    A method is described of treatment of opacity of the lens of an eye resulting from foreign matter at the back surface of the eye lens within the vitreous fluid body of the eye with a passively Q-switched laser device. The method consists of: (a) generating a single lasing pulse emitted from the laser device focused within the eye vitreous fluid body, spaced from the lens back surface, creating a microplasma dot in the vitreous fluid body (b) then increasing the frequency of the lasing pulses emitted from the lasing device having a frequency greater than the life of the microplasma to generate an elongated lasing plasma within the eye vitreous fluid moving toward the lens back surface, until the elongated lasing plasma contacts and destroys the foreign matter

  1. Primary anterior chamber intraocular lens for the treatment of severe crystalline lens subluxation.

    Science.gov (United States)

    Hoffman, Richard S; Fine, I Howard; Packer, Mark

    2009-10-01

    Subluxated cataractous and clear lenses are commonly treated by limbal or pars plana lensectomy followed by primary or secondary intraocular lens (IOL) implantation. Adjunctive capsular prosthetic devices have facilitated lens removal and IOL centration in these challenging cases but have also added complexity and potential complications to the procedure. Although crystalline lens extraction may be required to clear the visual axis in mild to moderate lens subluxations, we propose insertion of a primary anterior chamber IOL without lens extraction in severe subluxations when the eye is optically aphakic or can be made functionally aphakic following neodymium:YAG laser zonulysis. Two cases demonstrating this approach are presented.

  2. Fabricating customized hydrogel contact lens

    Science.gov (United States)

    Childs, Andre; Li, Hao; Lewittes, Daniella M.; Dong, Biqin; Liu, Wenzhong; Shu, Xiao; Sun, Cheng; Zhang, Hao F.

    2016-10-01

    Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.

  3. Protection of the eye lens

    International Nuclear Information System (INIS)

    2015-01-01

    The limit of radiation exposure for eye lens is going to decrease dramatically from 150 to 20 mSv as a transposition into the French law of a CIPR (International Commission for Radiation Protection) directive. Sanitary studies have shown that radiologists are more likely by a factor of 3.8 to get eye lens opacities than the rest of the population. The wearing of protective glasses is recommended and in order to get a better monitoring of the radiation dose new dosimeters have been designed, they can be worn on the glass frame of directly stuck on the skin near the eyes. A study has shown that veterinary surgeons that are accustomed to stay near animals to keep them quiet during radiological exams are prone to receive high doses as well as physicians that use hypnosis to decrease the level of anxiety of their patients during radiological exams. Radiation exposure of radiologists can be mitigated through: the use of protective shields and equipment and the optimization of the dose delivered to the patient. (A.C.)

  4. Color corrected Fresnel lens for solar concentration

    International Nuclear Information System (INIS)

    Kritchman, E.M.

    1979-01-01

    A new linear convex Fresnel lens with its groove side down is described. The design philosophy is similar to the highly concentrating two focal Fresnel lens but including a correction for chromatic aberration. A solar concentration ratio as high as 80 is achieved. For wide acceptance angles the concentration nears the theoretical maximum. (author)

  5. Analysis of a Thin Optical Lens Model

    Science.gov (United States)

    Ivchenko, Vladimir V.

    2011-01-01

    In this article a thin optical lens model is considered. It is shown that the limits of its applicability are determined not only by the ratio between the thickness of the lens and the modules of the radii of curvature, but above all its geometric type. We have derived the analytical criteria for the applicability of the model for different types…

  6. Mathematical Lens: How Much Can You Bench?

    Science.gov (United States)

    Bolognese, Chris A.

    2013-01-01

    "How Much Can You Bench?" appears in the "Mathematical Lens" section of "Mathematics Teacher." "Mathematical Lens" uses photographs as a springboard for mathematical inquiry and appears in every issue of "Mathematics Teacher." This month the mathematics behind the photograph includes finding areas…

  7. Plasma Lens for Muon and Neutrino Beams

    International Nuclear Information System (INIS)

    Kahn, S.A.; Korenev, S.; Bishai, M.; Diwan, M.; Gallardo, J.C.; Hershcovitch, A.; Johnson, B.M.

    2008-01-01

    The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high-energy lens/target configuration. The current is fed at electrodes located upstream and downstream from the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma for optimum focusing. The plasma lens is immersed in an additional solenoid magnetic field to facilitate the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. Plasma lenses have the additional advantage of negligible pion absorption and scattering by the lens material and reduced neutrino contamination during anti-neutrino running. Results of particle simulations using plasma lens will be presented

  8. IR and Raman spectroscopy of sodium aluminophosphate vitreous materials for immobilization of high level wastes from nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Stefanovskij, S.V.; Myasoedov, B.F.; Remizov, M.B.; Belanova, E.A.

    2014-01-01

    The structure of sodium aluminophosphate vitreous materials containing constituents of high level wastes (cesium, magnesium, copper and molybdenum oxides) from uranium-graphite reactor has been studied by IR and Raman spectroscopy techniques coupled with X-ray diffraction. The structural network has been shown to be composed of short phosphorus-oxygen chains with embedded aluminum-oxygen tetrahedra. In the magnesium-bearing samples the cross-linking with Mg 2+ ions is possible. The effect of other oxides (Cs 2 O, MoO 3 , CuO) on the glass structure is negligible for the occuring amounts. The glasses have been devitrified partly at the quenching and much stronger at the annealing. It is reflected in splitting of the vibration bands of the bonds in structural units of the anionic motif of the vitreous materials. (authors)

  9. Si-O-Si bond-angle distribution in vitreous silica from first-principles 29Si NMR analysis

    International Nuclear Information System (INIS)

    Mauri, Francesco; Pasquarello, Alfredo; Pfrommer, Bernd G.; Yoon, Young-Gui; Louie, Steven G.

    2000-01-01

    The correlation between 29 Si chemical shifts and Si-O-Si bond angles in SiO 2 is determined within density-functional theory for the full range of angles present in vitreous silica. This relation closely reproduces measured shifts of crystalline polymorphs. The knowledge of the correlation allows us to reliably extract from the experimental NMR spectrum the mean (151 degree sign ) and the standard deviation (11 degree sign ) of the Si-O-Si angular distribution of vitreous silica. In particular, we show that the Mozzi-Warren Si-O-Si angular distribution is not consistent with the NMR data. This analysis illustrates the potential of our approach for structural determinations of silicate glasses. (c) 2000 The American Physical Society

  10. Fabrication of Glass Microchannel via Glass Imprinting using a Vitreous Carbon Stamp for Flow Focusing Droplet Generator

    Science.gov (United States)

    Refatul Haq, Muhammad; Kim, Youngkyu; Kim, Jun; Oh, Pyoung-hwa; Ju, Jonghyun; Kim, Seok-Min; Lim, Jiseok

    2017-01-01

    This study reports a cost-effective method of replicating glass microfluidic chips using a vitreous carbon (VC) stamp. A glass replica with the required microfluidic microstructures was synthesized without etching. The replication method uses a VC stamp fabricated by combining thermal replication using a furan-based, thermally-curable polymer with carbonization. To test the feasibility of this method, a flow focusing droplet generator with flow-focusing and channel widths of 50 µm and 100 µm, respectively, was successfully fabricated in a soda-lime glass substrate. Deviation between the geometries of the initial shape and the vitreous carbon mold occurred because of shrinkage during the carbonization process, however this effect could be predicted and compensated for. Finally, the monodispersity of the droplets generated by the fabricated microfluidic device was evaluated. PMID:29286341

  11. Fabrication of Glass Microchannel via Glass Imprinting using a Vitreous Carbon Stamp for Flow Focusing Droplet Generator

    Directory of Open Access Journals (Sweden)

    Hyungjun Jang

    2017-12-01

    Full Text Available This study reports a cost-effective method of replicating glass microfluidic chips using a vitreous carbon (VC stamp. A glass replica with the required microfluidic microstructures was synthesized without etching. The replication method uses a VC stamp fabricated by combining thermal replication using a furan-based, thermally-curable polymer with carbonization. To test the feasibility of this method, a flow focusing droplet generator with flow-focusing and channel widths of 50 µm and 100 µm, respectively, was successfully fabricated in a soda-lime glass substrate. Deviation between the geometries of the initial shape and the vitreous carbon mold occurred because of shrinkage during the carbonization process, however this effect could be predicted and compensated for. Finally, the monodispersity of the droplets generated by the fabricated microfluidic device was evaluated.

  12. THEORETICAL GAS CONCENTRATIONS ACHIEVING 100% FILL OF THE VITREOUS CAVITY IN THE POSTOPERATIVE PERIOD: A Gas Eye Model Study.

    Science.gov (United States)

    Williamson, Tom H; Guillemaut, Jean-Yves; Hall, Sheldon K; Hutter, Joseph C; Goddard, Tony

    2017-12-11

    To determine the concentrations of different gas tamponades in air to achieve 100% fill of the vitreous cavity postoperatively and to examine the influence of eye volume on these concentrations. A mathematical model of the mass transfer dynamics of tamponade and blood gases (O2, N2, and CO2) when injected into the eye was used. Mass transfer surface areas were calculated from published anatomical data. The model has been calibrated from published volumetric decay and composition results for three gases sulphahexafluoride (SF6), hexafluoroethane (C2F6), or perfluoropropane (C3F8). The concentrations of these gases (in air) required to achieve 100% fill of the vitreous cavity postoperatively without an intraocular pressure rise were determined. The concentrations were calculated for three volumes of the vitreous cavity to test whether ocular size influenced the results. A table of gas concentrations was produced. In a simulation of pars plana vitrectomy operations in which an 80% to 85% fill of the vitreous cavity with gas was achieved at surgery, the concentrations of the 3 gases in air to achieve 100% fill postoperatively were 10% to 13% for C3F8, 12% to 15% for C2F6, and 19% to 25% for SF6. These were similar to the so-called "nonexpansive" concentrations used in the clinical setting. The calculations were repeated for three different sizes of eye. Aiming for an 80% fill at surgery and 100% postoperatively, an eye with a 4-mL vitreous cavity required 24% SF6, 15% C2F6, or 13% C3F8; 7.2 mL required 25% SF6, 15% C2F6, or 13% C3F8; and 10 mL required 25% SF6, 16% C2F6, or 13% C3F8. When using 100% gas (e.g., used in pneumatic retinopexy), to achieve 100% fill postoperatively, the minimum vitreous cavity fill at surgery was 43% for SF6, 29% for C2F6, and 25% for C3F8 and was only minimally changed by variation in the size of the eye. A table has been produced, which could be used for surgical innovation in gas usage in the vitreous cavity. It provides concentrations

  13. Study by electron paramagnetic resonance of the radiolysis of pyridine N-oxide in a vitreous methanol matrix

    International Nuclear Information System (INIS)

    Quaegebeur, J.P.; Perly, B.

    1977-01-01

    The analysis of esr spectra derived from γ irradiated pyridine N-oxide in a methanolic vitreous matrix at 77 K shows the presence of a mixture of 2- and 4-azacyclohexadienyl N-oxide radicals formed by the addition of the hydroxymethyl primary species to the pyridine ring. The structure of the different radicals was determined by comparison with spectra derived from several substituted pyridine N-oxides

  14. Application of PIXE to the characterization of vitreous dacites from archaeolgical sites in the Atacama region in northern Chile

    Energy Technology Data Exchange (ETDEWEB)

    Morales, J.R.; Cancino, S. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Nunoa, Santiago 1 (Chile); Miranda, P. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Nunoa, Santiago 1 (Chile)], E-mail: pjmirand@gmail.com; Dinator, M.I. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Nunoa, Santiago 1 (Chile); Seelenfreund, A. [Universidad Academia de Humanismo Cristiano, Condell 343, Providencia, Santiago (Chile)

    2007-11-15

    Geochemical characterization studies using PIXE were carried out on 21 vitreous dacite artifacts from early formative archaeological sites in the Atacama region, in northern Chile, and on 13 samples taken from two potential volcanic sources located within the region. Performing statistical analyses it was possible to obtain elemental concentration patterns for the archaeological samples of this material and match some of these artifacts with the geological source samples.

  15. Definition and manufacture of vitreous matrices using innovative processes for the confinement of nuclear wastes or industrial toxic wastes

    International Nuclear Information System (INIS)

    Boen, R.; Ladirat, C.; Lacombe, J.

    1997-01-01

    Vitrification appears as a solution to toxic mineral waste confinement; this solution has been demonstrated at an industrial level for radioactive wastes. The utilization of cold crucible direct induction melting furnaces, associated to various waste pre-treatments and well-adapted gas processing, leads to the confinement of numerous toxic mineral wastes in a borosilicate vitreous matrix which quality and long term behaviour may be precisely defined

  16. LensEnt2: Maximum-entropy weak lens reconstruction

    Science.gov (United States)

    Marshall, P. J.; Hobson, M. P.; Gull, S. F.; Bridle, S. L.

    2013-08-01

    LensEnt2 is a maximum entropy reconstructor of weak lensing mass maps. The method takes each galaxy shape as an independent estimator of the reduced shear field and incorporates an intrinsic smoothness, determined by Bayesian methods, into the reconstruction. The uncertainties from both the intrinsic distribution of galaxy shapes and galaxy shape estimation are carried through to the final mass reconstruction, and the mass within arbitrarily shaped apertures are calculated with corresponding uncertainties. The input is a galaxy ellipticity catalog with each measured galaxy shape treated as a noisy tracer of the reduced shear field, which is inferred on a fine pixel grid assuming positivity, and smoothness on scales of w arcsec where w is an input parameter. The ICF width w can be chosen by computing the evidence for it.

  17. Phototoxicity and cytotoxicity of fullerol in human lens epithelial cells

    International Nuclear Information System (INIS)

    Roberts, Joan E.; Wielgus, Albert R.; Boyes, William K.; Andley, Usha; Chignell, Colin F.

    2008-01-01

    The water-soluble, hydroxylated fullerene [fullerol, nano-C 60 (OH) 22-26 ] has several clinical applications including use as a drug carrier to bypass the blood ocular barriers. We have assessed fullerol's potential ocular toxicity by measuring its cytotoxicity and phototoxicity induced by UVA and visible light in vitro with human lens epithelial cells (HLE B-3). Accumulation of nano-C 60 (OH) 22-26 in the cells was confirmed spectrophotometrically at 405 nm and cell viability estimated using MTS and LDH assays. Fullerol was cytotoxic to HLE B-3 cells maintained in the dark at concentrations higher than 20 μM. Exposure to either UVA or visible light in the presence of > 5 μM fullerol-induced phototoxic damage. When cells were pretreated with non-toxic antioxidants: 20 μM lutein, 1 mM N-acetyl cysteine, or 1 mM L-ascorbic acid prior to irradiation, only the singlet oxygen quencher-lutein significantly protected against fullerol photodamage. Apoptosis was observed in lens cells treated with fullerol whether or not the cells were irradiated, in the order UVA > visible light > dark. Dynamic light scattering (DLS) showed that in the presence of the endogenous lens protein α-crystallin, large aggregates of fullerol were reduced. In conclusion, fullerol is both cytotoxic and phototoxic to human lens epithelial cells. Although the acute toxicity of water-soluble nano-C 60 (OH) 22-26 is low, these compounds are retained in the body for long periods, raising concern for their chronic toxic effect. Before fullerols are used to deliver drugs to the eye, they should be tested for photo- and cytotoxicity in vivo

  18. Measurement of amino acid levels in the vitreous humor of rats after chronic intraocular pressure elevation or optic nerve transection.

    Science.gov (United States)

    Levkovitch-Verbin, Hana; Martin, Keith R G; Quigley, Harry A; Baumrind, Lisa A; Pease, Mary Ellen; Valenta, Danielle

    2002-10-01

    To investigate whether the levels of free amino acids and protein in the vitreous of rat eyes are altered with chronic intraocular pressure (IOP) elevation or after optic nerve transection. The concentrations of 20 amino acids in the vitreous humor were measured by high-performance liquid chromatography in both eyes of 41 rats with unilateral IOP elevation induced by translimbal photocoagulation. Eyes were studied 1 day and 1, 2, 4, and 9 weeks after initial IOP elevation. The same amino acids were measured in 41 rats 1 day and 2, 4, and 9 weeks after unilateral transection of the orbital optic nerve. The intravitreal protein level was assayed in additional 22 rats with IOP elevation and 12 rats after nerve transection. Two masked observers evaluated the amount of optic nerve damage with a semiquantitative, light-microscopic technique. In rats with experimental glaucoma, amino acid concentrations were unchanged 1 day after treatment. At 1 week, 4 of 20 amino acids (aspartate, proline, alanine, and lysine) were higher than in control eyes ( 0.05). Vitreous protein level was significantly higher in glaucomatous eyes than their paired controls at 1 day ( 0.01).

  19. Non-vitrectomizing vitreous surgery and adjuvant intravitreal tissue plasminogen activator for non-recent massive premacular hemorrhage

    Directory of Open Access Journals (Sweden)

    Tsung-Tien Wu

    2011-12-01

    Full Text Available Massive premacular hemorrhage can cause sudden visual loss. We sought to evaluate the efficacy, safety and visual outcome of nonvitrectomizing vitreous surgery with intravitreal tissue plasminogen activator (t-pa for long-lasting thick premacular hemorrhage. This retrospective, interventional study examined three consecutive eyes of three patients who received nonvitrectomizing vitreous surgery with intravitreal t-pa for the treatment of non-recent massive premacular hemorrhage. Detailed ophthalmoscopic examinations were performed pre- and postoperatively to evaluate the visual outcome, the resolution of premacular hemorrhage and the changes in lenticular opacity.In all three eyes, the premacular hemorrhage cleared after the procedure. Final best-corrected visual acuities improved from 6/30 to 6/10 in patient 1, 2/60 to 6/4 in patient 2, and 3/60 to 6/6 in patient 3. Operated and fellow eyes did not differ in terms of nuclear sclerosis. No complications from the procedure were noted.In these selected cases, nonvitrectomizing vitreous surgery with intravitreal t-pa was an effective and safe alternative treatment for non-recent massive premacular hemorrhage.

  20. Correlative Microscopy of Vitreous Sections Provides Insights into BAR-Domain Organization In Situ.

    Science.gov (United States)

    Bharat, Tanmay A M; Hoffmann, Patrick C; Kukulski, Wanda

    2018-04-10

    Electron microscopy imaging of macromolecular complexes in their native cellular context is limited by the inherent difficulty to acquire high-resolution tomographic data from thick cells and to specifically identify elusive structures within crowded cellular environments. Here, we combined cryo-fluorescence microscopy with electron cryo-tomography of vitreous sections into a coherent correlative microscopy workflow, ideal for detection and structural analysis of elusive protein assemblies in situ. We used this workflow to address an open question on BAR-domain coating of yeast plasma membrane compartments known as eisosomes. BAR domains can sense or induce membrane curvature, and form scaffold-like membrane coats in vitro. Our results demonstrate that in cells, the BAR protein Pil1 localizes to eisosomes of varying membrane curvature. Sub-tomogram analysis revealed a dense protein coat on curved eisosomes, which was not present on shallow eisosomes, indicating that while BAR domains can assemble at shallow membranes in vivo, scaffold formation is tightly coupled to curvature generation. Copyright © 2018 MRC Laboratory of Molecular Biology. Published by Elsevier Ltd.. All rights reserved.

  1. Smart platform for the time since death determination from vitreous humor cystine.

    Science.gov (United States)

    Ansari, Niha; Lodha, Anand; Menon, Shobhana K

    2016-12-15

    In this work, we report the smart application of AgNPs based sensors for determination of time since death (TSD) via recognition and quantification of vitreous humor (VH) cystine as well as provide the portability for on spot determination of TSD. The lower detection limit was found to be 7.0ng/ml with prominent selectivity. It was found that there is a linear correlation between the VH cystine concentration and TSD as the concentration of cystine increases up to 96h±3.9h. Further for the first time TSD determination is given a smart approach and it proves to have a great utility up to 24h±2.6h. The linear regression equation between TSD (the dependent variable), RGB intensity of cystine concentration till 24h (the independent variable) was found to be TSD=26.69+-0.05*x. The proposed method gives the smart detection, portability, rapidity, sensitivity, selectivity as well as cost effectiveness for determination of time since death. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Evaluation of the vitreous matrices to include high-level radioactive wastes

    International Nuclear Information System (INIS)

    Varani, J.L.; Petraitis, E.J.; Pasquali, R.C.

    1987-01-01

    The Argentine Nuclear Programme considers a fuel cycle with Pu recycle. This will generate high-level liquid wastes, that should be safely eliminated. With this purpose, primary glasses utilizing three prototipe compositions were prepared. Simulated wastes oxides in the rate of about 10% were added to the vitreous matrices. The mixture was melted in ceramic melting pots in a muffle furnace at 1 100 deg C during 8 hours. Resistance leaching tests were made following an adaptation of the DIN 12 111 standard. Quantitative analysis of the leaching solutions were made to evaluate the solubility of the different elements. Glasses were observed with optical microscopy scanning before and after leaching. In the first, glasses, bubbles and crystalline-phase appear; in the second ones, puncture and embrittlement were detected. By means of differential thermoanalysis, endo and exothermal peaks were identified in glasses supporting gradual heating. X ray diffraction analysis were made in samples with and without wastes. The degree of crystallization of samples was evaluated by photographic and diffractometric techniques. Leaching studies showed the existance of a direct relation between leaching and glass alkaline content. (M.E.L.) [es

  3. Removal of Cd 2+ ion from diluted aqueous solutions by electrodeposition on reticulated vitreous carbon electrodes

    Directory of Open Access Journals (Sweden)

    Tramontina Jucelânia

    2002-01-01

    Full Text Available The electrodeposition of Cd2+ ion was investigated in pH 4.8 sulfuric-sulfate solutions in the presence of dissolved O2. In potentiostatic conditions, using reticulated vitreous carbon (RVC electrodes of 30, 60 and 100 pores per inch (ppi, high removal efficiency values were achieved in the potential range from --0.90 to --1.10 V for solutions containing 5 and 10 mg L-1 of Cd2+ ion. In this potential range, Cd electrodeposition is a mass transport controlled reaction and the concentration of the metallic ion decays exponentially with time following a pseudo-first order kinetics. For the 30 ppi RVC, the current efficiency and removal efficiency values found were, respectively, 45 % and 96 % for a solution containing 10 mg L-1 of Cd2+ ion after 30 minutes electrolysis at --0.90 V while 33 % and 99% were found for the 60 ppi RVC. The concentration decay of Cd2+ ion in the solution was monitored after each experiment by anodic stripping voltammetry at a hanging mercury drop electrode.

  4. Removal of Cd+2 from aqueous solutions onto polypyrrole coated reticulated vitreous carbon eletrodes

    Directory of Open Access Journals (Sweden)

    Tramontina Jucelânia

    2001-01-01

    Full Text Available The development of simple methods for removal of heavy metals from aqueous samples is a relevant field of research. In this connection, the electrodeposition of the Cd+2 ion, one of the most toxic species for animals and human beings, was investigated in aerated pH 4.8 sulfuric-sulfate solutions. In potentiostatic conditions, the maximum rate of cadmium deposition at a neutral polypyrrole (PPy0 coated reticulated vitreous carbon (RVC working electrode occurs at -3.0 V vs. the saturated calomel reference electrode (SCE. Moreover, the conversion rate depends both on the applied potential and on the mass transport regime, and, for solutions containing 10 mg L-1 of Cd2+, the highest removal efficiency achieved is 84% after 90 min of electrolysis. The concentration decay of the Cd+2 ion in the solution was monitored by anodic stripping voltammetry (ASV at a hanging mercury drop electrode. Besides, metallic cadmium deposited onto the polypyrrole modified RVC electrode was evidenced by Scanning Electron Microscopy (SEM analysis using the backscattered electron image (BEI technique and by Energy Dispersive Spectrometry (EDS.

  5. Simultaneous quantification of cocaine, amphetamines, opiates and cannabinoids in vitreous humor.

    Science.gov (United States)

    Peres, Mariana Dadalto; Pelição, Fabrício Souza; Caleffi, Bruno; De Martinis, Bruno Spinosa

    2014-01-01

    A GC-MS method for simultaneous analysis of cocaine (COC), amphetamines (AMPs), opiates, cannabinoids and their metabolites in vitreous humor (VH) was developed and fully validated. VH samples were extracted using solid phase extraction and injected into the GC-MS, using a selected ion monitoring mode. Linearity ranged from 10 to 1000 ng/mL; the exception was anhydroecgonine methyl ester (AEME), for which linearity ranged from 10 to 750 ng/mL. Inter-assay imprecision lay from 1.2 to 10.0%, intra-assay imprecision was samples taken from individuals whose blood had screened positive for drugs of abuse. All the individuals screened positive for COC in the blood (seven samples) also had positive results in VH; COC concentration ranged from 30.81 to 283.97 ng/mL (mean 186.98 ng/mL) and benzoylecgonine concentration ranged from 11.47 to 460.98 ng/mL (mean 133.91 ng/mL). It was also noticed that, in five cases, cocaethylene was detected. AEME was also quantified in one case. The use of AMP detected by blood analysis was confirmed in the VH of one individual (24.31 ng/mL). However, samples taken from three individuals whose blood tested positive for carboxy-tetrahydrocannabinol presented negative results. The results demonstrated that VH is a suitable alternative biological sample to determine COC, AMPs, opiates and their metabolites.

  6. Effect of neutron irradiation on the density of low-energy excitations in vitreous silica

    International Nuclear Information System (INIS)

    Smith, T.L.

    1979-01-01

    Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity were made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found that the irradiation produced changes of the same relative magnitude in the low-temperature excess specific heat C/sub ex/, the thermal conductivity kappa, and the anomalous temperature dependence of the ultrasound velocity Δv/v. A corresponding change in the temperature dependent dielectric constant was not observed. It is therefore likely that kappa and Δv/v are determined by the same localized excitations responsible for C/sub ex/, but the temperature dependence of the dielectric constant may have a different, though possibly related, origin. A consistent account for the measured C/sub ex/, kappa, and Δv/v of unirradiated silica is given by the tunneling-state model with a single, energy-dependent density of states. Changes in these three properties due to irradiation can be explained by altering only the density of tunneling states incorporated in the model

  7. Development of a thin film vitreous bond based composite ceramic coating for corrosion and abrasion services

    International Nuclear Information System (INIS)

    Franke, B.

    2003-01-01

    IPC has been involved with the Alberta Research Council in developing a vitreous bond (VB) - based composite ceramic fluoropolymer coating technology. Compared to the present state of the art which is based on a hard discontinuous phase (ceramic particles) suspended in a soft continuous matrix (fluoropolymer mix) the novelty of our approach consists of designing a composite system in which both the ceramic and the fluoropolymer phases are continuous. The ceramic matrix will provide the strength and the erosion resistance for the fluoropolymer matrix even at high temperatures. The ceramic formulation employed is not affected by temperatures up to 500 o F while the fluoropolymer matrix provides a corrosion protection seal for the ceramic matrix. The inherent flexibility of the polymer matrix will protect against brittle fractures that may develop by handling or impact. Therefore the composite coating is able to withstand the deformation of the substrate without chipping or disbanding. The fluoropolymer matrix also provides dry lubrication properties further enhancing the erosion resistance of the ceramic phase. The thickness of the coating is very thin, in the 25 to 100 micron range. In summary, the coating technology is able to provide the following features: Corrosion protection levels similar to those of fluoropolymer coatings; Erosion resistance similar to that of ceramic coatings; Price comparable to that of polymer coatings; Exceptional wear resistance properties; and Capability for coating complicated shapes internally or externally or both. This paper will discuss the theory and development of this new technology and the resultant coating and potential properties. (author)

  8. Evaluation of porous vitreous carbon or silicon implants by radiology in rat's skull

    International Nuclear Information System (INIS)

    Vaccari-Mazzetti, Marcelo Paulo; Kobata, Celio Toshiro; Fabiani, Paulo; Martins, Dulce Maria Fonseca Soares; Gomes, Paulo de Oliveira; Martins, Jose Luiz

    2008-01-01

    Purpose: Evaluate by CT the use of porous vitreous carbon (PVC) and silicon (S) implants as the replacement bone in the craniofacial skeleton of rats. Methods: 40 rats divided in: Group A (n=20) PVC submitted to the implant of a fragment in skull. After the euthanasia, the animals were divided into two subgroups: A I: 10 animals, studied in the 7th postoperative day (P.O) and AII: 10 animals, studied in the 28th P.O. In group B, S, 20 rats were submitted to S implant in the skull. All other steps were identical to group A, with designation of subgroups BI and BII. CT with beams in axial cuts of 1 mm thickness to obtain 3-D information It was used Hounsfield scale for evaluate the radio density of the implant. They were used non parametric tests to analyze the results. Results: The 7th PO boss remained in the two groups, but for 28th PO, observed reduction in the volume of the implant in Group A, not observed in group B. CT studies noticed different radio densities around all of S prostheses (pseudo capsule), that do not appeared in CPV implants. The S has remained unchanged in the CT, but the CPV has had a modification in its radio density (p≤0,05), in all implants. Conclusion: In CT evaluation the implants of CPV have greater deformation that the S, which makes them not suitable for replacement of membranous bone in the rat skull. (author)

  9. Managing the consequences of aggressive conservative treatment for refractory retinoblastoma with vitreous seeding

    Directory of Open Access Journals (Sweden)

    Aubrey Brink

    2014-08-01

    Full Text Available A 4 year-old girl with bilateral, non-familial retinoblastoma (RB was referred to our care after primary enucleation OS and active tumor OD refractory to multiple therapies (intravenous chemotherapy, laser/cryotherapy, and I-125 plaque radiotherapy. Vitreous seeding OD, initially controlled by several sessions of Ophthalmic Artery Infusion Chemotherapy (OAIC and periocular chemotherapy, recurred shortly thereafter. The patient underwent intravitreal (IVit Melphalan injections achieving tumor control despite the concurrent development of keratopathy, pupillary synechiae, cataract, and necrosis of the inferior fornix and the adjacent orbital fat, all secondary to the treatments administered. Repeated amniotic membrane implants and tarsorrhaphy were performed to alleviate the symptoms. Despite being tumor free for 6 months, a poor fundus view and treatment-related complications prompted us to consider enucleation, but parents declined. Following recent negative magnetic resonance imaging (MRI, her cataract was removed. She was then found to have tumor recurrence. Her eye was enucleated 12 months ago and she recovered well from the surgery. As ocular oncology embarks in eye-preserving treatments for retinoblastoma, it is important to address the cumulative effects and associated impact of such treatments and the possibility of failure.

  10. Er:YAB nanoparticles and vitreous thin films by the polymeric precursor method

    Energy Technology Data Exchange (ETDEWEB)

    Maia, Lauro J. Q., E-mail: lauro@if.sc.usp.b [Universidade de Sao Paulo, Grupo Crescimento de Cristais e Materiais Ceramicos, Departamento de Fisica e Ciencia dos Materiais, Instituto de Fisica de Sao Carlos (Brazil); Ibanez, Alain; Ortega, Luc [Laboratoire de Cristallographie CNRS associe a l' Universite Joseph Fourier et a l' INPG (France); Mastelaro, Valmor R.; Hernandes, Antonio C. [Universidade de Sao Paulo, Grupo Crescimento de Cristais e Materiais Ceramicos, Departamento de Fisica e Ciencia dos Materiais, Instituto de Fisica de Sao Carlos (Brazil)

    2008-12-15

    The synthesis of Y{sub 0.9}Er{sub 0.1}Al{sub 3}(BO{sub 3}){sub 4} crystalline powders and vitreous thin films were studied. Precursor solutions were obtained using a modified polymeric precursor method using d-sorbitol as complexant agent. The chemical reactions were described. Y{sub 0.9}Er{sub 0.1}Al{sub 3}(BO{sub 3}){sub 4} composition presents good thermal stability with regard to crystallization. The Y{sub 0.9}Er{sub 0.1}Al{sub 3}(BO{sub 3}){sub 4} crystallized phase can be obtained at 1,150 {sup o}C, in agreement with other authors. Crack- and porosity-free films were obtained with very small grain size and low RMS roughness. The films thickness revealed to be linearly dependent on precursor solution viscosity, being the value of 25 mPa s useful to prepare high-quality amorphous multi-layers (up to {approx} 800 nm) at 740 {sup o}C during 2 h onto silica substrates by spin coating with a gyrset technology.

  11. Characterization of reticulated vitreous carbon foam using a frisch-grid parallel-plate ionization chamber

    Science.gov (United States)

    Edwards, Nathaniel S.; Conley, Jerrod C.; Reichenberger, Michael A.; Nelson, Kyle A.; Tiner, Christopher N.; Hinson, Niklas J.; Ugorowski, Philip B.; Fronk, Ryan G.; McGregor, Douglas S.

    2018-06-01

    The propagation of electrons through several linear pore densities of reticulated vitreous carbon (RVC) foam was studied using a Frisch-grid parallel-plate ionization chamber pressurized to 1 psig of P-10 proportional gas. The operating voltages of the electrodes contained within the Frisch-grid parallel-plate ionization chamber were defined by measuring counting curves using a collimated 241Am alpha-particle source with and without a Frisch grid. RVC foam samples with linear pore densities of 5, 10, 20, 30, 45, 80, and 100 pores per linear inch were separately positioned between the cathode and anode. Pulse-height spectra and count rates from a collimated 241Am alpha-particle source positioned between the cathode and each RVC foam sample were measured and compared to a measurement without an RVC foam sample. The Frisch grid was positioned in between the RVC foam sample and the anode. The measured pulse-height spectra were indiscernible from background and resulted in negligible net count rates for all RVC foam samples. The Frisch grid parallel-plate ionization chamber measurement results indicate that electrons do not traverse the bulk of RVC foam and consequently do not produce a pulse.

  12. Vitreous humor analysis for the detection of xenobiotics in forensic toxicology: a review.

    Science.gov (United States)

    Bévalot, Fabien; Cartiser, Nathalie; Bottinelli, Charline; Fanton, Laurent; Guitton, Jérôme

    2016-01-01

    Vitreous humor (VH) is a gelatinous substance contained in the posterior chamber of the eye, playing a mechanical role in the eyeball. It has been the subject of numerous studies in various forensic applications, primarily for the assessment of postmortem interval and for postmortem chemical analysis. Since most of the xenobiotics present in the bloodstream are detected in VH after crossing the selective blood-retinal barrier, VH is an alternative matrix useful for forensic toxicology. VH analysis offers particular advantages over other biological matrices: it is less prone to postmortem redistribution, is easy to collect, has relatively few interfering compounds for the analytical process, and shows sample stability over time after death. The present study is an overview of VH physiology, drug transport and elimination. Collection, storage, analytical techniques and interpretation of results from qualitative and quantitative points of view are dealt with. The distribution of xenobiotics in VH samples is thus discussed and illustrated by a table reporting the concentrations of 106 drugs from more than 300 case reports. For this purpose, a survey was conducted of publications found in the MEDLINE database from 1969 through April 30, 2015.

  13. A new perspective in the estimation of postmortem interval (PMI) based on vitreous.

    Science.gov (United States)

    Muñoz, J I; Suárez-Peñaranda, J M; Otero, X L; Rodríguez-Calvo, M S; Costas, E; Miguéns, X; Concheiro, L

    2001-03-01

    The relation between the potassium concentration in the vitreous humor, [K+], and the postmortem interval has been studied by several authors. Many formulae are available and they are based on a correlation test and linear regression using the PMI as the independent variable and [K+] as the dependent variable. The estimation of the confidence interval is based on this formulation. However, in forensic work, it is necessary to use [K+] as the independent variable to estimate the PMI. Although all authors have obtained the PMI by direct use of these formulae, it is, nevertheless, an inexact approach, which leads to false estimations. What is required is to change the variables, obtaining a new equation in which [K+] is considered as the independent variable and the PMI as the dependent. The regression line obtained from our data is [K+] = 5.35 + 0.22 PMI, by changing the variables we get PMI = 2.58[K+] - 9.30. When only nonhospital deaths are considered, the results are considerably improved. In this case, we get [K+] = 5.60 + 0.17 PMI and, consequently, PMI = 3.92[K+] - 19.04.

  14. On the Possibility of Calculating Entropy, Free Energy, and Enthalpy of Vitreous Substances

    Directory of Open Access Journals (Sweden)

    Sergei V. Nemilov

    2018-03-01

    Full Text Available A critical analysis for the arguments in support of, and against, the traditional approach to thermodynamics of vitreous state is provided. In this approach one presumes that there is a continuous variation of the entropy in the glass-liquid transition temperature range, or a “continuous entropy approach” towards 0 K which produces a positive value of the entropy at T → 0 K. I find that arguments given against this traditional approach use a different understanding of the thermodynamics of glass transition on cooling a liquid, because it suggests a discontinuity or “entropy loss approach” in the variation of entropy in the glass-liquid transition range. That is based on: (1 an unjustifiable use of the classical Boltzmann statistics for interpreting the value of entropy at absolute zero; (2 the rejection of thermodynamic analysis of systems with broken ergodicity, even though the possibility of analogous analysis was proposed already by Gibbs; (3 the possibility of a finite change in entropy of a system without absorption or release of heat; and, (4 describing the thermodynamic properties of glasses in the framework of functions, instead of functionals. The last one is necessary because for glasses the entropy and enthalpy are not functions of the state, but functionals, as defined by Gibbs’ in his classification.

  15. Reticulated vitreous carbon doped with nano silver metallic particles for antimicrobial inhibitory application

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Ana Paula Silva; Oishi, Silvia; Marcuzzo, Jossano Saldanha; Baldan, Mauricio Ribeiro, E-mail: silvadeoliveira.ana@gmail.com [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil); Ito, Cristiane Yoga; Goncalves, Emerson Sarmento [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sao Paulo, SP (Brazil)

    2016-07-01

    Full text: The development of composites for biocides application has attracted considerable attention in several research fields. Silver nanoparticles is a very know antimicrobial material.Manufacturing composite materials with high surface area and biocides characteristics is challenge. In this work was studied the morphological and structural characterization of silver nanoparticles dispersed in a structure of carbon Reticulated Vitreous (CVR), treated at different temperatures, resulting in a nanocomposite.The silver impregnation technique in carbon materials is not a simple work due to its chemical stability. The objective in this study was to evaluate the deposition of silver nanoparticles on the CVR as a composite material for microorganisms inhibition or eliminate. The characterization of the material will be carried out using the Raman spectroscopy, spectroscopy Photoelectron Excited by X-rays, diffraction X-ray-EDS.Through the results it was concluded that the CRV treated at 1300 ° C showed the highest concentration of silver on its structure. These results potentiate the deposition of silver nanoparticles on CRV structures and disorganized with large concentration of active sites to anchor silver particles. In addition, the average size of the deposited particles decreases due to heat treatment. (author)

  16. Reticulated vitreous carbon doped with nano silver metallic particles for antimicrobial inhibitory application

    International Nuclear Information System (INIS)

    Oliveira, Ana Paula Silva; Oishi, Silvia; Marcuzzo, Jossano Saldanha; Baldan, Mauricio Ribeiro; Ito, Cristiane Yoga; Goncalves, Emerson Sarmento

    2016-01-01

    Full text: The development of composites for biocides application has attracted considerable attention in several research fields. Silver nanoparticles is a very know antimicrobial material.Manufacturing composite materials with high surface area and biocides characteristics is challenge. In this work was studied the morphological and structural characterization of silver nanoparticles dispersed in a structure of carbon Reticulated Vitreous (CVR), treated at different temperatures, resulting in a nanocomposite.The silver impregnation technique in carbon materials is not a simple work due to its chemical stability. The objective in this study was to evaluate the deposition of silver nanoparticles on the CVR as a composite material for microorganisms inhibition or eliminate. The characterization of the material will be carried out using the Raman spectroscopy, spectroscopy Photoelectron Excited by X-rays, diffraction X-ray-EDS.Through the results it was concluded that the CRV treated at 1300 ° C showed the highest concentration of silver on its structure. These results potentiate the deposition of silver nanoparticles on CRV structures and disorganized with large concentration of active sites to anchor silver particles. In addition, the average size of the deposited particles decreases due to heat treatment. (author)

  17. Results of intraocular lens implantation with capsular tension ring in subluxated crystalline or cataractous lenses in children.

    Science.gov (United States)

    Das, Pranab; Ram, Jagat; Brar, Gagandeep Singh; Dogra, Mangat R

    2009-01-01

    To evaluate the outcome of intraocular lens (IOL) implantation using capsular tension ring (CTR) in subluxated crystalline or cataractous lenses in children. Tertiary care setting. We prospectively studied 18 eyes of 15 children with subluxation of crystalline or cataractous lenses between 90 degrees up to 210 degrees after phacoemulsification, CTR and IOL implantation. Each child was examined for IOL centration, zonular dehiscence and posterior capsular opacification (PCO). Age of the patient ranged between five to 15 years. Out of 18 eyes, seven had traumatic and 11 had spontaneous subluxation of crystalline or cataractous lens. Phacoemulsification was successfully performed with CTR implantation in the capsular bag. Intraoperative zonular dialysis occurred in two eyes. Anterior vitrectomy was performed in six eyes to manage vitreous prolapse. IOL implanted was polymethyl methacrylate (PMMA) in eight eyes, hydrophobic acrylic in seven and hydrophilic acrylic in three. Follow-up ranged from 24 months to 72 months. Sixteen eyes had a best corrected visual acuity of 20/40 or better. Nine eyes developed significant PCO and were managed with Neodymium Yttrium Aluminum Garnet (Nd:YAG) laser posterior capsulotomy. One eye with acrylic IOL in the capsular bag had IOL dislocation after two years which was managed with vitrectomy and secondary trans-scleral fixation of IOL. Phacoaspiration with CTR implantation makes capsular bag IOL fixation possible in most of the eyes with subluxated crystalline or cataractous lenses. PCO still remains a challenge in children with successful phacoaspiration with CTR implantation.

  18. Results of intraocular lens implantation with capsular tension ring in subluxated crystalline or cataractous lenses in children

    Directory of Open Access Journals (Sweden)

    Das Pranab

    2009-01-01

    Full Text Available Purpose : To evaluate the outcome of intraocular lens (IOL implantation using capsular tension ring (CTR in subluxated crystalline or cataractous lenses in children. Setting : Tertiary care setting Materials and Methods : We prospectively studied 18 eyes of 15 children with subluxation of crystalline or cataractous lenses between 90° up to 210° after phacoemulsification, CTR and IOL implantation. Each child was examined for IOL centration, zonular dehiscence and posterior capsular opacification (PCO. Results : Age of the patient ranged between five to 15 years. Out of 18 eyes, seven had traumatic and 11 had spontaneous subluxation of crystalline or cataractous lens. Phacoemulsification was successfully performed with CTR implantation in the capsular bag. Intraoperative zonular dialysis occurred in two eyes. Anterior vitrectomy was performed in six eyes to manage vitreous prolapse. IOL implanted was polymethyl methacrylate (PMMA in eight eyes, hydrophobic acrylic in seven and hydrophilic acrylic in three. Follow-up ranged from 24 months to 72 months. Sixteen eyes had a best corrected visual acuity of 20/40 or better. Nine eyes developed significant PCO and were managed with Neodymium Yttrium Aluminum Garnet (Nd:YAG laser posterior capsulotomy. One eye with acrylic IOL in the capsular bag had IOL dislocation after two years which was managed with vitrectomy and secondary trans-scleral fixation of IOL. Conclusions : Phacoaspiration with CTR implantation makes capsular bag IOL fixation possible in most of the eyes with subluxated crystalline or cataractous lenses. PCO still remains a challenge in children with successful phacoaspiration with CTR implantation

  19. Lessons learned: wrong intraocular lens.

    Science.gov (United States)

    Schein, Oliver D; Banta, James T; Chen, Teresa C; Pritzker, Scott; Schachat, Andrew P

    2012-10-01

    To report cases involving the placement of the wrong intraocular lens (IOL) at the time of cataract surgery where human error occurred. Retrospective small case series, convenience sample. Seven surgical cases. Institutional review of errors committed and subsequent improvements to clinical protocols. Lessons learned and changes in procedures adapted. The pathways to a wrong IOL are many but largely reflect some combination of poor surgical team communication, transcription error, lack of preoperative clarity in surgical planning or failure to match the patient, and IOL calculation sheet with 2 unique identifiers. Safety in surgery involving IOLs is enhanced both by strict procedures, such as an IOL-specific "time-out," and the fostering of a surgical team culture in which all members are encouraged to voice questions and concerns. Copyright © 2012 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  20. Radiation studies in Lens culinaris

    International Nuclear Information System (INIS)

    Sinha, S.S.N.

    1977-01-01

    Estimation of chromosomal aberrations in flowers of Lens culinaris according to their sequence of development in the plants at 4, 8 and 12 Kr in the M 1 generation, showed that the later formed flowers had smaller percentages of cells with aberrations than those developed earlier. It is suggested that this may be the result of competition between more damaged and less damaged cells during the development of the shoot. There is consequently a decrease of sterility in successive flowers. The numbers of karyotypes taking part in the formation of lower and uppermost flowers were estimated cytologically at 4, 8 and 12 Kr. It was found that more karyotypes were involved in the formation of the lower flowers than in the upper ones. It appeared that at lower doses larger numbers of karyotypes were taking part in the formation of the chimaera than at higher doses. (auth.)

  1. Precision lens assembly with alignment turning system

    Science.gov (United States)

    Ho, Cheng-Fang; Huang, Chien-Yao; Lin, Yi-Hao; Kuo, Hui-Jean; Kuo, Ching-Hsiang; Hsu, Wei-Yao; Chen, Fong-Zhi

    2017-10-01

    The poker chip assembly with high precision lens barrels is widely applied to ultra-high performance optical system. ITRC applies the poker chip assembly technology to the high numerical aperture objective lenses and lithography projection lenses because of its high efficiency assembly process. In order to achieve high precision lens cell for poker chip assembly, an alignment turning system (ATS) is developed. The ATS includes measurement, alignment and turning modules. The measurement module is equipped with a non-contact displacement sensor (NCDS) and an autocollimator (ACM). The NCDS and ACM are used to measure centration errors of the top and the bottom surface of a lens respectively; then the amount of adjustment of displacement and tilt with respect to the rotational axis of the turning machine for the alignment module can be determined. After measurement, alignment and turning processes on the ATS, the centration error of a lens cell with 200 mm in diameter can be controlled within 10 arcsec. Furthermore, a poker chip assembly lens cell with three sub-cells is demonstrated, each sub-cells are measured and accomplished with alignment and turning processes. The lens assembly test for five times by each three technicians; the average transmission centration error of assembly lens is 12.45 arcsec. The results show that ATS can achieve high assembly efficiency for precision optical systems.

  2. Bioinspired adaptive gradient refractive index distribution lens

    Science.gov (United States)

    Yin, Kezhen; Lai, Chuan-Yar; Wang, Jia; Ji, Shanzuo; Aldridge, James; Feng, Jingxing; Olah, Andrew; Baer, Eric; Ponting, Michael

    2018-02-01

    Inspired by the soft, deformable human eye lens, a synthetic polymer gradient refractive index distribution (GRIN) lens with an adaptive geometry and focal power has been demonstrated via multilayer coextrusion and thermoforming of nanolayered elastomeric polymer films. A set of 30 polymer nanolayered films comprised of two thermoplastic polyurethanes having a refractive index difference of 0.05 were coextruded via forced-assembly technique. The set of 30 nanolayered polymer films exhibited transmission near 90% with each film varying in refractive index by 0.0017. An adaptive GRIN lens was fabricated from a laminated stack of the variable refractive index films with a 0.05 spherical GRIN. This lens was subsequently deformed by mechanical ring compression of the lens. Variation in the optical properties of the deformable GRIN lens was determined, including 20% variation in focal length and reduced spherical aberration. These properties were measured and compared to simulated results by placido-cone topography and ANSYS methods. The demonstration of a solid-state, dynamic focal length, GRIN lens with improved aberration correction was discussed relative to the potential future use in implantable devices.

  3. Pax6- and Six3-mediated induction of lens cell fate in mouse and human ES cells.

    Directory of Open Access Journals (Sweden)

    Raymond M Anchan

    Full Text Available Embryonic stem (ES cells provide a potentially useful in vitro model for the study of in vivo tissue differentiation. We used mouse and human ES cells to investigate whether the lens regulatory genes Pax6 and Six3 could induce lens cell fate in vitro. To help assess the onset of lens differentiation, we derived a new mES cell line (Pax6-GFP mES that expresses a GFP reporter under the control of the Pax6 P0 promoter and lens ectoderm enhancer. Pax6 or Six3 expression vectors were introduced into mES or hES cells by transfection or lentiviral infection and the differentiating ES cells analyzed for lens marker expression. Transfection of mES cells with Pax6 or Six3 but not with other genes induced the expression of lens cell markers and up-regulated GFP reporter expression in Pax6-GFP mES cells by 3 days post-transfection. By 7 days post-transfection, mES cell cultures exhibited a>10-fold increase over controls in the number of colonies expressing γA-crystallin, a lens fiber cell differentiation marker. RT-PCR and immunostaining revealed induction of additional lens epithelial or fiber cell differentiation markers including Foxe3, Prox1, α- and β-crystallins, and Tdrd7. Moreover, γA-crystallin- or Prox1-expressing lentoid bodies formed by 30 days in culture. In hES cells, Pax6 or Six3 lentiviral vectors also induced lens marker expression. mES cells that express lens markers reside close to but are distinct from the Pax6 or Six3 transduced cells, suggesting that the latter induce nearby undifferentiated ES cells to adopt a lens fate by non-cell autonomous mechanisms. In sum, we describe a novel mES cell GFP reporter line that is useful for monitoring induction of lens fate, and demonstrate that Pax6 or Six3 is sufficient to induce ES cells to adopt a lens fate, potentially via non-cell autonomous mechanisms. These findings should facilitate investigations of lens development.

  4. Design of a hyperbolic microwave metallic lens

    International Nuclear Information System (INIS)

    Uckan, T.

    1979-12-01

    Due to problems caused by multiple reflections in the cavity walls of the EBT fusion research device, the use of a horn becomes important for the directivity of waves in the millimetric range. An ordinary dielectric lens cannot be used because of plasma-wall interactions. Microwave metallic lenses, designed to focus the energy into a plane wave, can improve the directivity considerably. By implementing a 70-GHz standard-gain horn with a delay-type hyperbolic lens, which consists of a solid metallic disk with a number of equal size small holes has indicated a gain of 15 dB over the no lens case

  5. Accelerating convergence in automatic lens design

    International Nuclear Information System (INIS)

    Brixner, B.

    1981-01-01

    Among the various factors that slow lens optimization-insufficient performance targets, the absence of a unique solution, false local minima, a poorly scaled change vector, failure to find the optimum damping number, and failure to equalize the parameter gradients-the importance of parameter gradient equalization has been insufficiently recognized. Gradients can be approximately equalized by scaling the lens to a suitable size while it is being optimized. For best results, the size of the damping number should also be optimized during each iteration. If these two procedures are followed, scaling the change vector is usually not crucial. To illustrate the importance of parameter equalization, a lens optimization is analyzed

  6. Single-lens 3D digital image correlation system based on a bilateral telecentric lens and a bi-prism: validation and application.

    Science.gov (United States)

    Wu, Lifu; Zhu, Jianguo; Xie, Huimin

    2015-09-10

    By using the principle of stereovision, 3D digital image correlation (3D-DIC) can determine the 3D morphology and deformation of a target and has been widely used in experimental mechanics as a noncontact 3D measurement technique. To eliminate the limitations of the conventional 3D-DIC system, this study proposes a calibration-free single-lens 3D-DIC system based on a bilateral telecentric lens and a bi-prism. The performance of the proposed system is verified by tests of rigid-body translation along the out-of-plane direction. As a comparison, the same rigid-body translations are measured using a single-entocentric-lens 3D-DIC system. The results show that the measurement accuracy of the proposed system is higher than that of the entocentric-lens-based one. As an application, the proposed system is used to measure the thermal linear expansion of a ceramic plate at elevated temperatures. The reasonable measurement results verify its applicability in deformation measurements, even in high-temperature environments.

  7. 21 CFR 886.1395 - Diagnostic Hruby fundus lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic Hruby fundus lens. 886.1395 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1395 Diagnostic Hruby fundus lens. (a) Identification. A diagnostic Hruby fundus lens is a device that is a 55 diopter lens intended for use in the...

  8. 21 CFR 886.5844 - Prescription spectacle lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Prescription spectacle lens. 886.5844 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5844 Prescription spectacle lens. (a) Identification. A prescription spectacle lens is a glass or plastic device that is a lens intended to be worn by...

  9. 21 CFR 886.1390 - Flexible diagnostic Fresnel lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Flexible diagnostic Fresnel lens. 886.1390 Section... (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1390 Flexible diagnostic Fresnel lens. (a) Identification. A flexible diagnostic Fresnel lens is a device that is a very thin lens which has...

  10. Sutureless intrascleral intraocular lens fixation with lamellar dissection of scleral tunnel

    Directory of Open Access Journals (Sweden)

    Kawaji T

    2016-01-01

    Full Text Available Takahiro Kawaji,1,2 Tomoki Sato,2 Hidenobu Tanihara11Department of Ophthalmology, Faculty of Life Sciences, Kumamoto University, Chuo-ku, 2Sato Eye & Internal Medicine Clinic, Kumamoto, JapanPurpose: To report the results of sutureless scleral fixation of a posterior chamber intraocular lens (IOL by using our developed simple technique.Methods: We retrospectively reviewed the medical records of 48 eyes of 47 patients who underwent sutureless intrascleral IOL fixation by using our modified technique. A 25-gauge microvitreoretinal knife was used to perform sclerotomies and create limbus-parallel scleral tunnels with lamellar dissection in which the haptics were fixed.Results: The IOLs were fixed and centered well. The mean follow-up period was 26.7 months. Postoperative complications included smooth vitreous hemorrhage in four eyes (8.3%, cystoid macular edema in two eyes (4.2%, and iris capture of the IOL in two eyes (4.2%. No other complications, such as breakage of the IOL, spontaneous IOL dislocation, or retinal detachment, were detected during the follow-up period.Conclusion: The lamellar dissection of the limbus-parallel scleral tunnel can simplify the forceps-assisted introduction of the haptics into the scleral tunnel, and this technique seemed to be safe.Keywords: intraocular lenses, ophthalmologic surgical procedures, intrascleral fixation, sutureless fixation

  11. Case of bilateral complete posterior dislocation of lens caused by elder abuse

    Directory of Open Access Journals (Sweden)

    Matsumoto Y

    2012-02-01

    Full Text Available Tetsuya Mutoh1,2, Thomas Tien2, Megumi Horie1, Yukihiro Matsumoto1, Makoto Chikuda11Department of Ophthalmology, Dokkyo Medical University Koshigaya Hospital, Koshigaya, Saitama, Japan; 2Department of Ophthalmology, Boston University School of Medicine, Boston, MA, USAAbstract: We report a case of bilateral complete dislocation of lenses into the vitreous cavities due to elder abuse in a patient with senile dementia. According to the patient’s son, bilateral complete lens dislocation occurred after he hit his father in the head with socks in order to control his violent behavior. Although the patient was taken to our ophthalmological ward for a planned vitrectomy, restlessness and inability to remain in his room during the night led to his leaving the hospital. The patient has not returned but did receive a vitrectomy at another clinic. While the number of patients with senile dementia has dramatically increased, no specific remedy is currently available. When treating medical concerns of seniors with unknown backgrounds, elder abuse needs to be considered as a potential cause of such injuries.Keywords: bilateral dislocation of lenses, elder abuse, senile dementia, vitrectomy

  12. Posterior chamber lens implantation with scleral fixation in children with traumatic cataract.

    Science.gov (United States)

    Caca, Ihsan; Sahin, Alparslan; Ari, Seyhmus; Alakus, Fuat

    2011-01-01

    To evaluate the outcomes of posterior chamber lens implantation with scleral fixation (SF-PCIOL) in children with traumatic cataract. Twenty-four eyes of 24 cases were included. All patients had corneal or corneoscleral lacerations that were primarily repaired. Traumatic cataract subsequently developed and SF-PCIOL was performed due to insufficient posterior capsule support. The average age of the patients was 5.8 years (range: 4 to 10 years). All cases had SF-PCIOL implanted via internal route using triangular double scleral flaps made of 9-0 polypropylene after a complete anterior vitrectomy. Average follow-up was 14.6 ± 4.3 months (range: 11 to 18 months). Visual acuity was increased at the last visit in 23 (96%) patients. Common postoperative complications were fibrinous reaction in 6 (25%) patients, transient intraocular pressure increase in 4 (17%) patients, membrane formation requiring removal in 1 (4%) patient, transient intraocular hemorrhage as vitreous hemorrhage in 1 (4%) patient, and retinal detachment in 1 (4%) patient after the postoperative second month. SF-PCIOL is an effective and reliable method in patients with pediatric traumatic cataract who had insufficient posterior capsule support. Copyright 2011, SLACK Incorporated.

  13. A dimensionless ordered pull-through model of the mammalian lens epithelium evidences scaling across species and explains the age-dependent changes in cell density in the human lens

    Science.gov (United States)

    Wu, Jun Jie; Wu, Weiju; Tholozan, Frederique M.; Saunter, Christopher D.; Girkin, John M.; Quinlan, Roy A.

    2015-01-01

    We present a mathematical (ordered pull-through; OPT) model of the cell-density profile for the mammalian lens epithelium together with new experimental data. The model is based upon dimensionless parameters, an important criterion for inter-species comparisons where lens sizes can vary greatly (e.g. bovine (approx. 18 mm); mouse (approx. 2 mm)) and confirms that mammalian lenses scale with size. The validated model includes two parameters: β/α, which is the ratio of the proliferation rate in the peripheral and in the central region of the lens; and γGZ, a dimensionless pull-through parameter that accounts for the cell transition and exit from the epithelium into the lens body. Best-fit values were determined for mouse, rat, rabbit, bovine and human lens epithelia. The OPT model accounts for the peak in cell density at the periphery of the lens epithelium, a region where cell proliferation is concentrated and reaches a maximum coincident with the germinative zone. The β/α ratio correlates with the measured FGF-2 gradient, a morphogen critical to lens cell survival, proliferation and differentiation. As proliferation declines with age, the OPT model predicted age-dependent changes in cell-density profiles, which we observed in mouse and human lenses. PMID:26236824

  14. Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher.

    Science.gov (United States)

    Marussich, Lauren; Manns, Fabrice; Nankivil, Derek; Maceo Heilman, Bianca; Yao, Yue; Arrieta-Quintero, Esdras; Ho, Arthur; Augusteyn, Robert; Parel, Jean-Marie

    2015-07-01

    To determine if the lens volume changes during accommodation. The study used data acquired on 36 cynomolgus monkey lenses that were stretched in a stepwise fashion to simulate disaccommodation. At each step, stretching force and dioptric power were measured and a cross-sectional image of the lens was acquired using an optical coherence tomography system. Images were corrected for refractive distortions and lens volume was calculated assuming rotational symmetry. The average change in lens volume was calculated and the relation between volume change and power change, and between volume change and stretching force, were quantified. Linear regressions of volume-power and volume-force plots were calculated. The mean (± SD) volume in the unstretched (accommodated) state was 97 ± 8 mm3. On average, there was a small but statistically significant (P = 0.002) increase in measured lens volume with stretching. The mean change in lens volume was +0.8 ± 1.3 mm3. The mean volume-power and volume-load slopes were -0.018 ± 0.058 mm3/D and +0.16 ± 0.40 mm3/g. Lens volume remains effectively constant during accommodation, with changes that are less than 1% on average. This result supports a hypothesis that the change in lens shape with accommodation is accompanied by a redistribution of tissue within the capsular bag without significant compression of the lens contents or fluid exchange through the capsule.

  15. AutoLens: Automated Modeling of a Strong Lens's Light, Mass and Source

    Science.gov (United States)

    Nightingale, J. W.; Dye, S.; Massey, Richard J.

    2018-05-01

    This work presents AutoLens, the first entirely automated modeling suite for the analysis of galaxy-scale strong gravitational lenses. AutoLens simultaneously models the lens galaxy's light and mass whilst reconstructing the extended source galaxy on an adaptive pixel-grid. The method's approach to source-plane discretization is amorphous, adapting its clustering and regularization to the intrinsic properties of the lensed source. The lens's light is fitted using a superposition of Sersic functions, allowing AutoLens to cleanly deblend its light from the source. Single component mass models representing the lens's total mass density profile are demonstrated, which in conjunction with light modeling can detect central images using a centrally cored profile. Decomposed mass modeling is also shown, which can fully decouple a lens's light and dark matter and determine whether the two component are geometrically aligned. The complexity of the light and mass models are automatically chosen via Bayesian model comparison. These steps form AutoLens's automated analysis pipeline, such that all results in this work are generated without any user-intervention. This is rigorously tested on a large suite of simulated images, assessing its performance on a broad range of lens profiles, source morphologies and lensing geometries. The method's performance is excellent, with accurate light, mass and source profiles inferred for data sets representative of both existing Hubble imaging and future Euclid wide-field observations.

  16. Placement of a crystalline lens and intraocular lens: Retinal image quality.

    Science.gov (United States)

    Siedlecki, Damian; Nowak, Jerzy; Zajac, Marek

    2006-01-01

    The influence of changes of both crystalline lens and intraocular lens (IOL) misalignment on the retinal image quality was investigated. The optical model of the eye used in investigations was the Liou-Brennan model, which is commonly considered as one of the most anatomically accurate. The original crystalline lens from this model was replaced with an IOL, made of rigid polymethylmethacrylate, in a way that recommend obligatory procedures. The modifications that were made both for crystalline lens and IOL were the longitudinal, the transversal, and the angular displacement.

  17. Development of Fresnel lens for improvement of rear visibility; Shikai kojo Fresnel lens no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, K; Sanada, C; Tsukino, M [Nissan Motor Co. Ltd., Tokyo (Japan)

    1997-10-01

    Fresnel lenses have been widely used to increase the visual field around vehicles for drivers. However, internal reflection in these lenses has been an obstacle in producing dear images. This internal glow is generated by incident light from an unexpected direction reflecting on the non-lens surface or radiating from the non-lens surface of the Fresnel lens. The cause of internal glow has been made dear combining louver film with the lens. The newly developed technology removes obstacles in producing dear images by reducing internal glow. 7 figs.

  18. Disinfection capacity of PuriLens contact lens cleaning unit against Acanthamoeba.

    Science.gov (United States)

    Hwang, Thomas S; Hyon, Joon Young; Song, Jae Kyung; Reviglio, Victor E; Spahr, Harry T; O'Brien, Terrence P

    2004-01-01

    The PuriLens contact lens system is indicated for cleaning and disinfection of soft (hydrophilic) contact lenses by means of subsonic agitation to remove lens deposits and microorganisms, and ultraviolet irradiation of the storage solution for disinfection. The capacity of the PuriLens system to disinfect storage solutions contaminated with known concentrations of Staphylococcus aureus, Pseudomonas aeruginosa, and Acanthamoeba species was evaluated. An in vitro assessment of the antibacterial and antiparasitic efficacy of the PuriLens system was performed. Separated batches of the storage solution for the cleansing system were contaminated with stock strains of S. aureus and P. aeruginosa. A comparison of the microbiologic content was made between the solution before and after the cycle. The PuriLens system effectively eradicated S. aureus and P. aeruginosa organisms after a 15-minute cycle. However, viable cysts of acanthamoeba were recovered in the solution after the 15-minute cycle. The PuriLens system is highly efficient in protecting against contamination with common bacterial ocular pathogens. Acanthamoeba cysts, however, can survive in the solution or contact lens bath undergoing integrated subsonic debridement and indirect ultraviolet light disinfection. Use of chemical disinfecting solutions that contain agents such as chlorhexidine or other cationic antiseptics may be advisable in conjunction with use of the PuriLens device, especially in high-risk settings.

  19. Night Vision Goggles Objectives Lens Focusing Methodology

    National Research Council Canada - National Science Library

    Pinkus, Alan; Task, H. L

    2000-01-01

    ...: interpupillary distance, tilt, eye relief, height, eyepiece and objective lens focus. Currently, aircrew use a Hoffman 20/20 test unit to pre-focus their NVG objective lenses at optical infinity before boarding their aircraft...

  20. Characteristics of soft X-ray lens

    International Nuclear Information System (INIS)

    Qin Yi

    2007-12-01

    A soft X-lens was devised with waveguide X-ray optics of total external reflection (TER). The lens consists of a stack of 1 387 TER waveguides with inner diameter of 0.45 mm and outer diameter of 0.60 mm. With the help of plasma sources of soft X-ray radiation, high density of pure soft X-ray radiation (without plasma expansion fragments) with broad-band spectral range can be obtained at the focus of the lens. As laser-plasma is considered, the radiation density of 1.3 x 10 5 W/cm 2 is obtained, the transmission coefficient is 18.6%, the ratio of the density at the focus with and without the lens is 1000 and the radiation capture is 28.9 degree. The density of 0.5 TW/cm 2 can be obtained as far as Qiang-Guang I facility is considered. (authors)

  1. Gravitational lens effect and pregalactic halo objects

    International Nuclear Information System (INIS)

    Bontz, R.J.

    1979-01-01

    The changes in flux, position, and size of a distant extended (galaxy, etc.) source that result from the gravitational lens action of a massive opaque object are discussed. The flux increase is described by a single function of two parameters. One of these parameters characterizes the strength of the gravitational lens, the other describes the alignment of source and lens object. This function also describes the relative intensity of the images formed by lens. ( A similar formalism is discussed by Bourassa et al. for a point source). The formalism is applied to the problem of the galactic halo. It appears that a massive (10 1 2 M/sub sun/) spherical halo surrounding the visible part of the galaxy is consistent with the observable properties of extragalactic sources

  2. Discovery of two new gravitation lens systems

    International Nuclear Information System (INIS)

    Guertler, J.

    1988-01-01

    The discovery of new quasar and radio galaxy double images produced by the gravitation lens effect is reported. The light deflecting galaxies acting as gravitational lenses could be made visible by means of image processing procedures

  3. A Plasma Lens for Magnetron Sputtering

    International Nuclear Information System (INIS)

    Anders, Andre; Brown, Jeff

    2010-01-01

    A plasma lens, consisting of a solenoid and potential-defining ring electrodes, has been placed between a magnetron and substrates to be coated. Photography reveals qualitative information on excitation, ionization, and the transport of plasma to the substrate.

  4. The discovery of a gravitational lens

    International Nuclear Information System (INIS)

    Chaffee, F.H. Jr.

    1981-01-01

    A recently discovered pair of quasars turns out to be not a pair at all but two images of a single quasar formed by a gravitational lens: an elliptical galaxy halfway between the quasar and our own galaxy. (orig.) [de

  5. EDEL: ENEA dosemeter for eye lens

    International Nuclear Information System (INIS)

    Ferrari, Paolo; Mariotti, Francesca; Campani, Lorenzo

    2016-01-01

    Since the publication of International Commission on Radiological Protection statement in 2011 on tissue reaction, eye lens radiation protection played an important role in exposed personnel dosimetry. For this reason, the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) Individual Monitoring Service decided to study a prototype to fulfil specific requests (e.g. for survey in interventional department and intercomparisons). On the basis of such preliminary investigation, a new eye lens dosemeter was developed. The new dosemeter, named EDEL (ENEA Dosemeter for Eye Lens), was characterised in terms of H p (3), the operational quantity related to eye lens monitoring. The investigation was performed experimentally and optimised using the Monte Carlo MCNP6 code. The new prototype was thought to fulfil two main requests: the reliability of the dosimetric data and the portability of the dosemeter itself. The new dosemeter will soon be supplied to the collaborating hospitals for workplace test measurements. (authors)

  6. Role of Aquaporin 0 in lens biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  7. Role of Aquaporin 0 in lens biomechanics.

    Science.gov (United States)

    Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0(+/-) lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to confer

  8. Raman spectroscopy of femtosecond multipulse irradiation of vitreous silica: Experiment and simulation

    Science.gov (United States)

    Shcheblanov, N. S.; Povarnitsyn, M. E.; Mishchik, K. N.; Tanguy, A.

    2018-02-01

    We report an experimental and numerical study of femtosecond multipulse laser-induced densification in vitreous silica (v -SiO2 ) and its signature in Raman spectra. We compare the experimental findings to the recently developed molecular dynamics (MD) approach accounting for bond breaking due to laser irradiation, together with a dynamical matrix approach and bond polarizability model based on first-principles calculations for the estimation of Raman spectra. We observe two stages of the laser-induced densification and Raman spectrum evolution: growth during several hundreds of pulses followed by further saturation. At the medium range, the network connectivity change in v -SiO2 is expressed in reduction of the major ring fractions leading to more compacted structure. With the help of the Sen and Thorpe model, we also study the short-range order transformation and derive the interbonding Si-O-Si angle change from the Raman measurements. Experimental findings are in excellent agreement with our MD simulations and hence support a bond-breaking mechanism of laser-induced densification. Thus, our modeling explains well the laser-induced changes both in the short-range order caused by the appearance of Si coordination defects and medium-range order connected to evolution of the ring distribution. Finally, our findings disclose similarities between sheared, permanently densified, and laser-induced glass and suggest interesting future experiments in order to clarify the impact of the thermomechanical history on glasses under shear, cold and hot compression, and laser-induced densification.

  9. Vibrational relaxation of a triatomic molecular impurity: D2O in vitreous As2S3

    International Nuclear Information System (INIS)

    Rella, C.W.; Schwettman, H.A.; Engholm, J.R.

    1995-01-01

    Measurements of the relaxation of the D 2 O stretch mode in vitreous As 2 S 3 are presented. Because the bending mode of the molecule offers an intra-molecular decay channel for the stretch mode, the decay scheme of the D 2 O molecule is more complex than that of diatomic molecules. The asymmetric stretch mode of D 2 O has a frequency of 2680 cm -1 . To study the relaxation of this mode we applied a pump-probe technique, using intense psec; pulses of the Stanford Free Electron Laser. Due to the small cross-section of the vibrational mode, successful efforts were made to improve the signal to noise ratio by using a laser stabilization system and a tightly focused beam to increase the intensity, by averaging the signal with a kHz repetition rate and by using samples with an optimized D 2 O concentration. A rapid relaxation rate on the order of 5 x 10 9 sec -1 at low temperature is found that increases with temperature. Recalling that the bending mode of the D 2 O molecule has a frequency of 1170 cm -1 , one would expect a decay in a third order process, involving two quanta of the bending mode plus a vibrational host quanta with a frequency of 340 cm -1 , which coincides with a fundamental frequency of the pyramidal building blocks of the glassy As 2 S 3 host. Instead, we find from the temperature dependence of the relaxation rate that the D 2 O stretching mode relaxes in a higher order process. This indicates that the relaxation dynamics of small molecules is more complex than generally assumed

  10. Microbial profile of the vitreous aspirates in culture proven exogenous endophthalmitis: A 10-year retrospective study

    Directory of Open Access Journals (Sweden)

    H Bhattacharjee

    2016-01-01

    Full Text Available Purpose: To describe the microbiological profile and clinical outcome in the eyes with culture-proven exogenous endophthalmitis. Methods: A retrospective analysis of 495 eyes diagnosed as exogenous endophthalmitis was performed over a period of 10 years. In all, aseptically collected aqueous and vitreous aspirates were cultured for bacteria and fungus using standard microbiological techniques. Gram-stain and KOH preparation of the specimens were also performed. The antibiotic susceptibility testing for bacterial isolates was performed by Kirby-Bauer disk diffusion method. The treatment was modified according to the antibiotic sensitivity profile. The final clinical ocular condition was divided into improved, stable or deteriorated. Results: Of 148 culture-proven endophthalmitis eyes, 137 (92.57% were referred from elsewhere, and 11 (7.43% belonged to our institute. Aetiologically, 76 (51.35% eyes were post-cataract surgery, 61 (41.22% were post-traumatic, 5 (3.38% eyes post-intravitreal anti-vascular endothelial growth factor injection, 5 associated with corneal diseases and 1 bleb-related endophthalmitis. In 31 (20.95% eyes, primary intravitreal antibiotics were given outside. The cultures revealed monomicrobial growth in 92.57% (n = 137 and polymicrobial growth in 7.43% (n = 11. Among the bacteria (n = 121, 81.76%, Pseudomonas species dominated overall (n = 32, 27.11% and post-operative (n = 26, 38.23% endophthalmitis group. Staphylococcus epidermidis (n = 14, 28% was prominent in post-traumatic endophthalmitis group. Ninety-two percent (n = 108 isolates of bacteria were sensitive to vancomycin. In 78 (52.7% eyes, the clinical ocular condition improved or remained stable while deteriorated in 51 (34.46%. Conclusion: A bacterial predominance was observed among causative organisms of exogenous endophthalmitis with Pseudomonas species being the most common. The appropriate surgical intervention improved or stabilised the visual acuity in nearly

  11. Cost-Utility of Evaluation for Posterior Vitreous Detachment and Prophylaxis of Retinal Detachment.

    Science.gov (United States)

    Yannuzzi, Nicolas A; Chang, Jonathan S; Brown, Gary C; Smiddy, William E

    2018-01-01

    To evaluate the costs and cost-utility of examination for posterior vitreous detachment (PVD) and treatment of associated pathology, and of managing various other peripheral retinal disorders to prevent retinal detachment (RD). A decision analysis model of cost-utility. There were no participants. Published retrospective data on the natural course of PVD, retinal tears, and lattice degeneration were used to quantitate the visual benefits of examination and treatment. Center for Medicare and Medicaid Services data were used to calculate associated modeled costs in a hospital/facility-based and nonfacility/ambulatory surgical center (ASC)-based setting. Published standards of utility for a given level of visual acuity were used to derive costs and quality-adjusted life years (QALYs). Cost of evaluation and treatment, utility of defined health states, QALY, and cost per QALY. The modeled cost of evaluation of a patient with PVD and treatment of associated pathology in the facility/hospital (nonfacility/ASC)-based setting was $65 to $190 ($25-$71) depending on whether a single or 2-examination protocol was used. The cost per QALY saved was $255 to $638/QALY ($100-$239/QALY). Treatment of a symptomatic horseshoe tear resulted in a net cost savings of $1749 ($1314) and improved utility, whereas treatment of an asymptomatic horseshoe tear resulted in $2981/QALY ($1436/QALY). Treatment of asymptomatic lattice degeneration in an eye in which the fellow eye had a history of RD resulted in $4414/QALY ($2187/QALY). Evaluation and management of incident acute PVD (and symptomatic horseshoe tears) offer a low cost and a favorable cost-utility (low $/QALY) as a result of the minimization of the cost and morbidity associated with the development of RD, thus justifying current practice standards. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  12. [The incidence of retinal tears in patients with posterior vitreous detachment].

    Science.gov (United States)

    Karaman, Ksenija; Gverović-Antunica, Antonela; Bućan, Kajo; Znaor, Ljubo; Bulović, Dijana; Skelin, Sinia

    2006-01-01

    Posterior vitreous detachment (PVD) is a common finding in older patients, characterized by detachment of the posterior hyaloid membrane (PHM) from the retinal surface. The detachment of PHM normally occurs without complications, however, one has to be aware that retinal tear is its most common complication. The aim of the study was to determine the incidence of retinal tears in eyes with PVD. A series of 40 patients (70 eyes) with PVD were included in this retrospective study. Eyes with a history of ocular trauma, surgery or intraocular inflammation were excluded. Patient charts were reviewed to collect the following information: age, sex, profession, type and duration of symptoms, best corrected visual acuity, refractive status, prior ocular disease, coincidental retinal pathology-lattice degeneration, number, type and location of retinal tears and treatment. Statistical analysis was done with the SPSS 11.0.3 software (SPSS Inc., USA). Besides descriptive statistics, Student's t-test and chi2-test were used. Among all study eyes with PVD, 34 (48.6%) were myopic, 24 (34.3%) hypermetropic and 12 (17.1%) emetropic; statistical analysis showed a significant difference (chi2 = 10.40, df=2, p lattice malignant degeneration of peripheral retinal was diagnosed. Thorough examination of the fundus periphery revealed 16 (22.8%) eyes with PVD were found to have retinal tears, 11 (15.7%) had only one retinal tear and 5 (7.1%) two retinal tears. All retinal tears were treated with argon laser photocoagulation. Superotemporal eye quadrant was the most common localization of retinal tears (56.25%). These results indicate that thorough fundus periphery examination should be done in all patients with PVD because it can cause rather rarely though retinal tears that represent a potentially sight threatening condition.

  13. Positron and positronium studies of irradiation-induced defects and microvoids in vitreous metamict silica

    International Nuclear Information System (INIS)

    Hasegawa, M.; Saneyasu, M.; Tabata, M.; Tang, Z.; Nagai, Y.; Chiba, T.; Ito, Y.

    2000-01-01

    To study irradiation-induced defects and structural microvoids in vitreous silica (v-SiO 2 ), positron lifetime, angular correlation of positron annihilation radiation (ACAR), and electron spin resonance (ESR) were measured on v-SiO 2 and quartz (c-SiO 2 ) samples irradiated with fast neutrons up to a dose of 4.1x10 20 n/cm 2 . Two kinds of positron-trapping defects have been found to form in v-SiO 2 by fast neutron irradiation: type-I and type-II defects. Similar defects also appear in the irradiated c-SiO 2 , indicating that both the defects are common in v-SiO 2 and c-SiO 2 . The detailed annealing and photo-illumination studies of positron annihilation and ESR for these two defects suggest that the type-I defects are non-bridging oxygen hole centers (NBOHC), while the type-II defects are oxygen molecules which cannot be detected by ESR. Higher dose irradiation than 1.0x10 20 n/cm 2 causes c-SiO 2 to change to metamict (amorphous) phase (m-SiO 2 ). Positronium (Ps) atoms are found to form in microvoids with an average radius of about 0.3 nm in the v-SiO 2 and m-SiO 2 . This suggests that microvoids proved by Ps are structurally intrinsic open spaces and reflect the topologically disordered structure of these phases in the subnanometer scale

  14. Evolution and the Calcite Eye Lens

    OpenAIRE

    Williams, Vernon L.

    2013-01-01

    Calcite is a uniaxial, birefringent crystal, which in its optically transparent form, has been used for animal eye lenses, the trilobite being one such animal. Because of the calcite birefringence there is a difficulty in using calcite as a lens. When the propagation direction of incoming light is not exactly on the c-axis, the mages blur. In this paper, calcite blurring is evaluated, and the non-blurring by a crystallin eye lens is compared to a calcite one.

  15. Lens Design Using Group Indices of Refraction

    Science.gov (United States)

    Vaughan, A. H.

    1995-01-01

    An approach to lens design is described in which the ratio of the group velocity to the speed of light (the group index) in glass is used, in conjunction with the more familiar phase index of refraction, to control certain chromatic properties of a system of thin lenses in contact. The first-order design of thin-lens systems is illustrated by examples incorporating the methods described.

  16. Orbiting objective lens telescope system and method

    International Nuclear Information System (INIS)

    Crooks, J.W. Jr.

    1984-01-01

    A large objective lens is placed in a highly eccentric orbit about the earth. The orbit and orientation of the lens are carefully chosen so that it focuses light or other radiation from a preselected astronomical object into an image which slowly moves across the surface of the earth. A row of optical sensing units is located on the surface of the earth so that the image focused by the orbiting objective lens will travel substantially perpendicularly across the row during an observation. Output data generated from the sensing units may be multiplexed and fed to a real time processor which produces display signals. Each of the sensing units provides one scan line of the image being observed. The display signals are fed to a suitable display device which produces a picture of the preselected astronomical object. The objective lens may comprise a large flexible Fresnel zone plate or a flexible convex lens carried by a bicycle wheel-type supporting structure. The lens and supporting structure may be unfolded from compact cargo configurations and rotated after being placed into orbit

  17. Photon nanojet lens: design, fabrication and characterization

    International Nuclear Information System (INIS)

    Xu, Chen; Zhang, Sichao; Shao, Jinhai; Lu, Bing-Rui; Chen, Yifang; Mehfuz, Reyad; Drakeley, Stacey; Huang, Fumin

    2016-01-01

    In this paper, a novel nanolens with super resolution, based on the photon nanojet effect through dielectric nanostructures in visible wavelengths, is proposed. The nanolens is made from plastic SU-8, consisting of parallel semi-cylinders in an array. This paper focuses on the lens designed by numerical simulation with the finite-difference time domain method and nanofabrication of the lens by grayscale electron beam lithography combined with a casting/bonding/lift-off transfer process. Monte Carlo simulation for injected charge distribution and development modeling was applied to define the resultant 3D profile in PMMA as the template for the lens shape. After the casting/bonding/lift-off process, the fabricated nanolens in SU-8 has the desired lens shape, very close to that of PMMA, indicating that the pattern transfer process developed in this work can be reliably applied not only for the fabrication of the lens but also for other 3D nanopatterns in general. The light distribution through the lens near its surface was initially characterized by a scanning near-field optical microscope, showing a well defined focusing image of designed grating lines. Such focusing function supports the great prospects of developing a novel nanolithography based on the photon nanojet effect. (paper)

  18. Contact lens rehabilitation following repaired corneal perforations

    Science.gov (United States)

    Titiyal, Jeewan S; Sinha, Rajesh; Sharma, Namrata; Sreenivas, V; Vajpayee, Rasik B

    2006-01-01

    Background Visual outcome following repair of post-traumatic corneal perforation may not be optimal due to presence of irregular keratometric astigmatism. We performed a study to evaluate and compare rigid gas permeable contact lens and spectacles in visual rehabilitation following perforating corneal injuries. Method Eyes that had undergone repair for corneal perforating injuries with or without lens aspiration were fitted rigid gas permeable contact lenses. The fitting pattern and the improvement in visual acuity by contact lens over spectacle correction were noted. Results Forty eyes of 40 patients that had undergone surgical repair of posttraumatic corneal perforations were fitted rigid gas permeable contact lenses for visual rehabilitation. Twenty-four eyes (60%) required aphakic contact lenses. The best corrected visual acuity (BCVA) of ≥ 6/18 in the snellen's acuity chart was seen in 10 (25%) eyes with spectacle correction and 37 (92.5%) eyes with the use of contact lens (p < 0.001). The best-corrected visual acuity with spectacles was 0.20 ± 0.13 while the same with contact lens was 0.58 ± 0.26. All the patients showed an improvement of ≥ 2 lines over spectacles in the snellen's acuity chart with contact lens. Conclusion Rigid gas permeable contact lenses are better means of rehabilitation in eyes that have an irregular cornea due to scars caused by perforating corneal injuries. PMID:16536877

  19. New trends in intraocular lens imaging

    Science.gov (United States)

    Millán, María S.; Alba-Bueno, Francisco; Vega, Fidel

    2011-08-01

    As a result of modern technological advances, cataract surgery can be seen as not only a rehabilitative operation, but a customized procedure to compensate for important sources of image degradation in the visual system of a patient, such as defocus and some aberrations. With the development of new materials, instruments and surgical techniques in ophthalmology, great progress has been achieved in the imaging capability of a pseudophakic eye implanted with an intraocular lens (IOL). From the very beginning, optical design has played an essential role in this progress. New IOL designs need, on the one hand, theoretical eye models able to predict optical imaging performance and on the other hand, testing methods, verification through in vitro and in vivo measurements, and clinical validation. The implant of an IOL requires a precise biometry of the eye, a prior calculation from physiological data, and an accurate position inside the eye. Otherwise, the effects of IOL calculation errors or misplacements degrade the image very quickly. The incorporation of wavefront aberrometry into clinical ophthalmology practice has motivated new designs of IOLs to compensate for high order aberrations in some extent. Thus, for instance, IOLs with an aspheric design have the potential to improve optical performance and contrast sensitivity by reducing the positive spherical aberration of human cornea. Monofocal IOLs cause a complete loss of accommodation that requires further correction for either distance or near vision. Multifocal IOLs address this limitation using the principle of simultaneous vision. Some multifocal IOLs include a diffractive zone that covers the aperture in part or totally. Reduced image contrast and undesired visual phenomena, such as halos and glare, have been associated to the performance of multifocal IOLs. Based on a different principle, accommodating IOLs rely on the effort of the ciliary body to increase the effective power of the optical system of the

  20. Conservation through the economics lens.

    Science.gov (United States)

    Farley, Joshua

    2010-01-01

    Although conservation is an inherently transdisciplinary issue, there is much to be gained from examining the problem through an economics lens. Three benefits of such an approach are laid out in this paper. First, many of the drivers of environmental degradation are economic in origin, and the better we understand them, the better we can conserve ecosystems by reducing degradation. Second, economics offers us a when-to-stop rule, which is equivalent to a when-to-conserve rule. All economic production is based on the transformation of raw materials provided by nature. As the economic system grows in physical size, it necessarily displaces and degrades ecosystems. The marginal benefits of economic growth are diminishing, and the marginal costs of ecological degradation are increasing. Conceptually, we should stop economic growth and focus on conservation when the two are equal. Third, economics can help us understand how to efficiently and justly allocate resources toward conservation, and this paper lays out some basic principles for doing so. Unfortunately, the field of economics is dominated by neoclassical economics, which builds an analytical framework based on questionable assumptions and takes an excessively disciplinary and formalistic approach. Conservation is a complex problem, and analysis from individual disciplinary lenses can make important contributions to conservation only when the resulting insights are synthesized into a coherent vision of the whole. Fortunately, there are a number of emerging transdisciplines, such as ecological economics and environmental management, that are dedicated to this task.

  1. [Study on the relationship between PMI and the concentration of magnesium and iron in the vitreous humor of rabbit after death].

    Science.gov (United States)

    Xu, Xiao-ming; Gong, Zhi-qiang; Sun, Yue-gang

    2002-05-01

    To seek a exact method of estimating postmortem interval (PMI). This study detected the concentration of magnesium (Mg) and iron (Fe) in vitreous humor of rabbit at 96 h after death and explored the relationship between their concentration and PMI using a method ICP-MS. The concentra-tion of Mg in vitreous humor of rabbit at 48 h after death and Fe in vitreous humor of rabbit at 6-48 h after death were related to PMI significantly. The formulae of the relationship between PMI and Mg concentrations is y = 0.0738x2 + 0.6997x + 11.45 (within 48 h, R2 = 0.9119). The formulae of the relationship between PMI and Fe concentrations is y = 0.0411x2 - 0.3148x + 1.4113 (within 6-48 h, R2 = 0.9594). The concentration of Mg in vitreous humor of rabbit at 48 h after death and Fe in vitreous humor of rabbit at 6-48 h after death may be as reference indicator to estimate PMI.

  2. A classification system of intraocular lens dislocation sites under operating microscopy, and the surgical techniques and outcomes of exchange surgery.

    Science.gov (United States)

    Hayashi, Ken; Ogawa, Soichiro; Manabe, Shin-Ichi; Hirata, Akira; Yoshimura, Koichi

    2016-03-01

    The aim of this study was to examine the recent status of intraocular lens (IOL) dislocation according to a classification system based on vertical dislocation position, as well as the surgical techniques and outcomes of IOL exchange surgery. The medical records of 230 eyes from 214 consecutive patients who experienced IOL dislocation and underwent exchange surgery between 2006 and 2014 were reviewed. Vertical dislocation sites observed preoperatively under operating microscopy were examined, along with the surgical techniques and outcomes of IOL exchange. Dislocation sites included (1) the anterior chamber (12.2 %), (2) pseudophakodonesis (19.1 %), (3) the anterior vitreous cavity (47.4 %), (4) trap door-like dislocation (dangling in the peripheral vitreous cavity; 16.1 %), and (5) the retinal surface (5.2 %). The IOL retained in the anterior segment was moved onto the iris by pulling it up through the limbal side ports with an anterior vitrectomy (67.8 %), or by pushing it up from the pars plana with an anterior vitrectomy (26.5 %), while the IOL dropped on the retina was lifting it up from the retina after pars plana vitrectomy (5.7 %). Mean uncorrected and distance-corrected visual acuity significantly improved postoperatively (p system, approximately 95 % of dislocated IOLs were retained in the anterior segment, and these IOLs were exchanged using an anterior approach through limbal incisions with an anterior vitrectomy. Visual acuity improved significantly, and serious complications were uncommon, probably because the IOL exchange techniques were standardized and simplified without pars plana vitrectomy.

  3. Comparison of the Results of Secondary Anterior Chamber and Secondary Scleral-Fixated Intraocular Lens Implantation in Complicated Phacoemulsification Cases

    Directory of Open Access Journals (Sweden)

    Nimet Yeşim Erçalık

    2014-03-01

    Full Text Available Objectives: To compare the visual prognosis and postoperative complication rates of secondary anterior chamber (AC IOL and scleralfixated (SF intraocular lenses (IOL after complicated phacoemulsification surgery. Materials and Methods: Thirty eyes of thirty patients were reviewed for this retrospective study. The patients with secondary AC IOL implantation formed group 1 (n=15, and the patients with secondary SF IOL implantation formed group 2 (n=15. Best-corrected visual acuity (BCVA with Snellen chart, biomicroscopic examination, intraocular pressure (IOP measurement with applanation tonometer, gonioscopy performed by Goldmann’s 3-mirror contact lens, and fundus examination were performed preoperatively in all patients. Results: There was no statistically significant difference in postoperative BCVA (p=0.492 and postoperative success (BCVA not changed or better postoperatively between the 2 groups (p=0.598. Postoperative success rate was 80% in group 1 and 93.7% in Group 2. The postoperative cylindrical power of the eyes did not differ significantly between the groups (p=0.220. The postoperative complications in group 1 were as follows: transient corneal edema in 5 eyes, transient IOP elevation in 2 eyes, postoperative fibrinous reaction in the anterior chamber in one eye, late-onset secondary glaucoma in one eye, hyphema in one eye, cystoid macular edema in one eye, vitreous prolapse into the anterior chamber in one eye, and IOL malposition in one eye. The postoperative complications in group 2 were as follows: transient corneal edema in 3 eyes, vitreous prolapse into the anterior chamber in 2 eyes, IOL malposition in 2 eyes, transient IOP elevation in one eye, and retinal detachment in one eye. Conclusion: In this study, both IOL types were observed to be preferable in cases without adequate capsular support following complicated cataract surgery. However, further studies with large numbers of patients are needed to define the best choice

  4. Peripheral Defocus of the Monkey Crystalline Lens With Accommodation in a Lens Stretcher

    Science.gov (United States)

    Maceo Heilman, Bianca; Manns, Fabrice; Ruggeri, Marco; Ho, Arthur; Gonzalez, Alex; Rowaan, Cor; Bernal, Andres; Arrieta, Esdras; Parel, Jean-Marie

    2018-01-01

    Purpose To characterize the peripheral defocus of the monkey crystalline lens and its changes with accommodation. Methods Experiments were performed on 15 lenses from 11 cynomolgus monkey eyes (age: 3.8–12.4 years, postmortem time: 33.5 ± 15.3 hours). The tissue was mounted in a motorized lens stretcher to allow for measurements of the lens in the accommodated (unstretched) and unaccommodated (stretched) states. A custom-built combined laser ray tracing and optical coherence tomography system was used to measure the paraxial on-axis and off-axis lens power for delivery angles ranging from −20° to +20° (in air). For each delivery angle, peripheral defocus was quantified as the difference between paraxial off-axis and on-axis power. The peripheral defocus of the lens was compared in the unstretched and stretched states. Results On average, the paraxial on-axis lens power was 52.0 ± 3.4 D in the unstretched state and 32.5 ± 5.1 D in the stretched state. In both states, the lens power increased with increasing delivery angle. From 0° to +20°, the relative peripheral lens power increased by 10.7 ± 1.4 D in the unstretched state and 7.5 ± 1.6 D in the stretched state. The change in field curvature with accommodation was statistically significant (P lens has greater curvature or relative peripheral power. Conclusions The cynomolgus monkey lens has significant accommodation-dependent curvature of field, which suggests that the lens asserts a significant contribution to the peripheral optical performance of the eye that also varies with the state of accommodation.

  5. Determination of the dose in eyes lens by TLD, in PET/CT by technicians in PET/CT service

    International Nuclear Information System (INIS)

    Marino, Emiliano A.

    2013-01-01

    This work was supported, on the one hand, in a part of the project ORAMED which consisted of a design of a TLD dosimeter for measurements of Hp (3) in areas close to the lens, for interventional radiology physicians. On the other hand, Berhens work proposes using calibrated TLDs Hp (0.07) and Hp (10) to estimate Hp (3) crystal. This resulted in dosimeters calibrated using Hp (10) slab, and mount them on glasses, to estimate the dose to the lens of the technical staff of the Service PET / CT. The value obtained 29mSv/year of Lens Dose Equivalent exceeds the recommended limit. We also demonstrate that, under the current working conditions, the values of Hp (3) reported from whole body dosimeter does not represent faithfully the lens dose

  6. Dose conversion coefficients for photon exposure of the human eye lens

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G

    2011-01-01

    In recent years, several papers dealing with the eye lens dose have been published, because epidemiological studies implied that the induction of cataracts occurs even at eye lens doses of less than 500 mGy. Different questions were addressed: Which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens? Is a new definition of the dose quantity H p (3) based on a cylinder phantom to represent the human head necessary? Are current conversion coefficients from fluence to equivalent dose to the lens sufficiently accurate? To investigate the latter question, a realistic model of the eye including the inner structure of the lens was developed. Using this eye model, conversion coefficients for electrons have already been presented. In this paper, the same eye model-with the addition of the whole body-was used to calculate conversion coefficients from fluence (and air kerma) to equivalent dose to the lens for photon radiation from 5 keV to 10 MeV. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are similar between 40 keV and 1 MeV and lower by up to a factor of 5 and 7 for photon energies at about 10 keV and 10 MeV, respectively. Above 1 MeV, the new values (calculated without kerma approximation) should be applied in pure photon radiation fields, while the values adopted by the ICRP in 1996 (calculated with kerma approximation) should be applied in case a significant contribution from secondary electrons originating outside the body is present.

  7. Regulating exposure of the lens of the eye to ionising radiations

    International Nuclear Information System (INIS)

    Thorne, M C

    2012-01-01

    The International Commission on Radiological Protection (ICRP) has reviewed recent epidemiological evidence suggesting that, for the lens of the eye, the threshold in absorbed dose for the induction of deleterious health effects is about 0.5 Gy. On this basis, the Commission recommends that for occupational exposure in planned exposure situations, the equivalent dose limit for the lens of the eye should be 20 mSv in a year, averaged over defined periods of 5 yr, with exposure not exceeding 50 mSv in any single year. This paper summarises the data that have been taken into account by the ICRP and critically examines whether the proposed downward revision of the dose limit is justified. Overall, it is concluded that the accumulating radiobiological and epidemiological evidence makes it more appropriate to treat cataract induction as a stochastic rather than a deterministic effect. Within this framework, it is illogical to have the same dose limit for the lens of the eye as for the whole body irradiated uniformly. This could be addressed either by removing the special dose limit for the lens of the eye, assigning it an appropriate tissue weighting factor and including it in the computation of the effective dose, or through a composite approach involving the use of a tissue weighting factor for effective dose computations together with a special limit on the equivalent dose to the lens of the eye to ensure that no individual was subject to an unacceptably high risk of induction of clinically significant cataracts.

  8. Sharing of secondary electrons by in-lens and out-lens detector in low-voltage scanning electron microscope equipped with immersion lens.

    Science.gov (United States)

    Kumagai, Kazuhiro; Sekiguchi, Takashi

    2009-03-01

    To understand secondary electron (SE) image formation with in-lens and out-lens detector in low-voltage scanning electron microscopy (LV-SEM), we have evaluated SE signals of an in-lens and an out-lens detector in LV-SEM. From the energy distribution spectra of SEs with various boosting voltages of the immersion lens system, we revealed that the electrostatic field of the immersion lens mainly collects electrons with energy lower than 40eV, acting as a low-pass filter. This effect is also observed as a contrast change in LV-SEM images taken by in-lens and out-lens detectors.

  9. Effects of scaffold surface morphology on cell adhesion and survival rate in vitreous cryopreservation of tenocyte-scaffold constructs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhi [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China); Department of Bone and Joint Surgery, The affiliated hospital of Luzhou Medical College, Luzhou 646000 (China); Qing, Quan [Sichuan College of Traditional Chinese Medicine, Mianyang 621000 (China); Regenerative Medicine Research Center, West China Hospital of Sichuan University, Chengdu 610041 (China); Chen, Xi; Liu, Cheng-Jun; Luo, Jing-Cong [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China); Hu, Jin-Lian [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China); Qin, Ting-Wu, E-mail: tingwuqin@hotmail.com [State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610041 (China)

    2016-12-01

    Highlights: • The shapes of tenocytes varied when seeded on different surface of scaffolds. • Tenocytes were flat on smooth surface and spindle on micro-grooved surface. • Tenocytes were ellipse or spindle on porous surface. • Tenocytes got varying adhesion shape and elongation index on varying surfaces. • The tenocyte survival on porous surface was superior to the other two groups. - Abstract: The purpose of this study was to investigate the effects of scaffold surface morphology on cell adhesion and survival rate in vitreous cryopreservation of tenocyte-scaffold constructs. Tenocytes were obtained from tail tendons of rats. Polydimethylsiloxane (PDMS) was used to fabricate three types of scaffolds with varying surface morphological characteristics, i.e., smooth, micro-grooved, and porous surfaces, respectively. The tenocytes were seeded on the surfaces of the scaffolds to form tenocyte-scaffold constructs. The constructs were cryopreserved in a vitreous cryoprotectant (CPA) with a multi-step protocol. The cell adhesion to scaffolds was observed with electronic scanning microscopy (SEM). The elongation index of the living tenocytes and ratio of live/dead cell number were examined based on a live/dead dual fluorescent staining technique, and the survival rate of tenocytes was studied with flow cytometry (FC). The results showed the shapes of tenocytes varied between the different groups: flat or polygonal (on smooth surface), spindle (on micro-grooved surface), and spindle or ellipse (on porous surface). After thawing, the porous surface got the most living tenocytes and a higher survival rate, suggesting its potential application for vitreous cryopreservation of engineered tendon constructs.

  10. MINERALIZATION OF RADIOACTIVE WASTES BY FLUIDIZED BED STEAM REFORMING (FBSR): COMPARISONS TO VITREOUS WASTE FORMS, AND PERTINENT DURABILITY TESTING

    International Nuclear Information System (INIS)

    Jantzen, C.

    2008-01-01

    The Savannah River National Laboratory (SRNL) was requested to generate a document for the Washington State Department of Ecology and the U.S. Environmental Protection Agency that would cover the following topics: (1) A description of the mineral structures produced by Fluidized Bed Steam Reforming (FBSR) of Hanford type Low Activity Waste (LAW including LAWR which is LAW melter recycle waste) waste, especially the cage structured minerals and how they are formed. (2) How the cage structured minerals contain some contaminants, while others become part of the mineral structure (Note that all contaminants become part of the mineral structure and this will be described in the subsequent sections of this report). (3) Possible contaminant release mechanisms from the mineral structures. (4) Appropriate analyses to evaluate these release mechanisms. (5) Why the appropriate analyses are comparable to the existing Hanford glass dataset. In order to discuss the mineral structures and how they bond contaminants a brief description of the structures of both mineral (ceramic) and vitreous waste forms will be given to show their similarities. By demonstrating the similarities of mineral and vitreous waste forms on atomic level, the contaminant release mechanisms of the crystalline (mineral) and amorphous (glass) waste forms can be compared. This will then logically lead to the discussion of why many of the analyses used to evaluate vitreous waste forms and glass-ceramics (also known as glass composite materials) are appropriate for determining the release mechanisms of LAW/LAWR mineral waste forms and how the durability data on LAW/LAWR mineral waste forms relate to the durability data for LAW/LAWR glasses. The text will discuss the LAW mineral waste form made by FBSR. The nanoscale mechanism by which the minerals form will be also be described in the text. The appropriate analyses to evaluate contaminant release mechanisms will be discussed, as will the FBSR test results to

  11. Nonlinear X-ray production of defect spins in vitreous SiO2: the roles of creation and activation

    International Nuclear Information System (INIS)

    Galeener, F.L.; Kerwin, D.B.; Miller, A.J.

    1992-01-01

    The dependence of spin concentration on X-ray dose is shown to be nonlinear in distinctive ways for the three most common defect structures in vitreous SiO 2 . We fit the data with a model invoking two concurrent simple processes: creation of new defects and activation of preexisting ones. The resultant fit parameters show dependencies on hydroxyl concentration and fictive temperature that shed new light on the processes, the defects, their origins and the radiation hardness of v-SiO 2 . (author)

  12. First-principles analysis of the Raman spectrum of vitreous silica: comparison with the vibrational density of states

    International Nuclear Information System (INIS)

    Umari, P; Pasquarello, Alfredo

    2003-01-01

    The HH and HV Raman spectra of vitreous silica are calculated from first principles for a model structure consisting of a disordered network of corner-sharing tetrahedra, for which the vibrational properties were obtained previously. We analyse the contribution of specific atomic motions to the Raman spectra and perform a detailed comparison with respect to the vibrational density of states. We find that the HV spectrum closely resembles the vibrational density of states. By comparison, the HH spectrum shows significant differences and arises almost exclusively from oxygen vibrations

  13. First-principles analysis of the Raman spectrum of vitreous silica: comparison with the vibrational density of states

    Energy Technology Data Exchange (ETDEWEB)

    Umari, P; Pasquarello, Alfredo [Institut de Theorie des Phenomenes Physiques (ITP), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Institut Romand de Recherche Numerique en Physique des Materiaux (IRRMA), CH-1015 Lausanne (Switzerland)

    2003-04-30

    The HH and HV Raman spectra of vitreous silica are calculated from first principles for a model structure consisting of a disordered network of corner-sharing tetrahedra, for which the vibrational properties were obtained previously. We analyse the contribution of specific atomic motions to the Raman spectra and perform a detailed comparison with respect to the vibrational density of states. We find that the HV spectrum closely resembles the vibrational density of states. By comparison, the HH spectrum shows significant differences and arises almost exclusively from oxygen vibrations.

  14. Medium-range structural properties of vitreous germania obtained through first-principles analysis of vibrational spectra.

    Science.gov (United States)

    Giacomazzi, Luigi; Umari, P; Pasquarello, Alfredo

    2005-08-12

    We analyze the principal vibrational spectra of vitreous GeO(2) and derive therefrom structural properties referring to length scales beyond the basic tetrahedral unit. We generate a model structure that yields a neutron structure factor in accord with experiment. The inelastic-neutron, the infrared, and the Raman spectra, calculated within a density-functional approach, also agree with respective experimental spectra. The accord for the Raman spectrum supports a Ge-O-Ge angle distribution centered at 135 degrees. The Raman feature X(2) is found to result from vibrations in three-membered rings, and therefore constitutes a distinctive characteristic of the medium-range structure.

  15. Post-lens tear turbidity and visual quality after scleral lens wear.

    Science.gov (United States)

    Carracedo, Gonzalo; Serramito-Blanco, Maria; Martin-Gil, Alba; Wang, Zicheng; Rodriguez-Pomar, Candela; Pintor, Jesús

    2017-11-01

    The aim was to evaluate the turbidity and thickness of the post-lens tear layer and its effect on visual quality in patients with keratoconus after the beginning of lens wear and before lens removal at the end of eight hours. Twenty-six patients with keratoconus (aged 36.95 ± 8.95 years) participated voluntarily in the study. The sample was divided into two groups: patients with intrastromal corneal ring (ICRS group) and patients without ICRS (KC group). Distance visual acuity (VA), contrast sensitivity, pachymetry, post-lens tear layer height and post-lens tear layer turbidity (percentage area occupied and number of particles per mm 2 ) were evaluated with optical coherence tomography before and after wearing a scleral lens. A significant increase of turbidity was found in all groups assessed (p turbidity parameters with distance VA but no correlation between turbidity and post-lens tear layer thickness at the beginning was found (p > 0.05). A strong correlation in all groups between the post-lens tear layer at the beginning and differences of tear layer thickness between two measures was also found (p turbidity. © 2017 Optometry Australia.

  16. Effect of infusion bottle height on lens power after lens refilling with and without a plug

    NARCIS (Netherlands)

    Koopmans, SA; Terwee, T; Haitjema, HJ; Kooijman, AC; Barkhof, J

    2003-01-01

    Purpose: To evaluate the influence of intraoperative infusion bottle height on the power of refilled pig lenses. Setting: Research Laboratory, Pharmacia Intraocular Lens Manufacturing Plant, Groningen, The Netherlands. Methods: This study comprised 2 groups of pig eyes. In 1 group, the lens was

  17. Disassembly of the lens fiber cell nucleus to create a clear lens: the p27 descent

    Science.gov (United States)

    The eye lens is unique among tissues: it is transparent, does not form tumors, and the majority of its cells degrade their organelles, including their cell nuclei. A mystery for over a century, there has been considerable recent progress in elucidating mechanisms of lens fiber cell denucleation (LFC...

  18. Nuclear magnetic resonance studies of lens transparency

    International Nuclear Information System (INIS)

    Beaulieu, C.F.

    1989-01-01

    Transparency of normal lens cytoplasm and loss of transparency in cataract were studied by nuclear magnetic resonance (NMR) methods. Phosphorus ( 31 P) NMR spectroscopy was used to measure the 31 P constituents and pH of calf lens cortical and nuclear homogenates and intact lenses as a function of time after lens enucleation and in opacification produced by calcium. Transparency was measured with laser spectroscopy. Despite complete loss of adenosine triphosphate (ATP) within 18 hrs of enucleation, the homogenates and lenses remained 100% transparent. Additions of calcium to ATP-depleted cortical homogenates produced opacification as well as concentration-dependent changes in inorganic phosphate, sugar phosphates, glycerol phosphorylcholine and pH. 1 H relaxation measurements of lens water at 200 MHz proton Larmor frequency studied temperature-dependent phase separation of lens nuclear homogenates. Preliminary measurements of T 1 and T 2 with non-equilibrium temperature changes showed a change in the slope of the temperature dependence of T 1 and T 2 at the phase separation temperature. Subsequent studies with equilibrium temperature changes showed no effect of phase separation on T 1 or T 2 , consistent with the phase separation being a low-energy process. 1 H nuclear magnetic relaxation dispersion (NMRD) studies (measurements of the magnetic field dependence of the water proton 1/T 1 relaxation rates) were performed on (1) calf lens nuclear and cortical homogenates (2) chicken lens homogenates, (3) native and heat-denatured egg white and (4) pure proteins including bovine γ-II crystallin bovine serum albumin (BSA) and myoglobin. The NMRD profiles of all samples exhibited decreases in 1/T 1 with increasing magnetic field

  19. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    International Nuclear Information System (INIS)

    Konvalina, I.; Muellerova, I.

    2011-01-01

    The cathode lens is an electron optical element in an emission electron microscope accelerating electrons from the sample, which serves as a source for a beam of electrons. Special application consists in using the cathode lens first for retardation of an illuminating electron beam and then for acceleration of reflected as well as secondary electrons, made in the directly imaging low energy electron microscope or in its scanning version discussed here. In order to form a real image, the cathode lens has to be combined with a focusing magnetic lens or a focusing immersion-magnetic lens, as used for objective lenses of some commercial scanning electron microscopes. These two alternatives are compared with regards to their optical properties, in particular with respect to predicted aberration coefficients and the spot size, as well as the optimum angular aperture of the primary beam. The important role of the final aperture size on the image resolution is also presented.

  20. Photosensitized oxidation in the ocular lens: evidence for photosensitizers endogenous to the human lens

    International Nuclear Information System (INIS)

    Zigler, J.S. Jr.; Goosey, J.D.

    1981-01-01

    Numerous investigators have attempted to associate near UV light exposure with various changes which occur to lens crystallins during aging and cataractogenesis. Recently it was shown that in vitro singlet oxygen mediated oxidation of lens crystallins produces effects very similar to those documented for crystallins from old or cataractous lenses and it was suggested that near UV photodynamic effects may play a major role in vivo in aging in the human lens. It has now been shown that certain oxidation products of tryptophan which have been identified in human lens can act as near UV photosensitizers, producing singlet oxygen. The insoluble protein fraction from human cataracts was shown to have the capacity to act as a photosensitizer. An age-related increase in photosensitizing capacity was also demonstrated in the soluble crystallins from human lens. These findings are discussed with respect to development of pigmented nuclear cataracts. (author)

  1. Optical integration of Pancharatnam-Berry phase lens and dynamical phase lens

    International Nuclear Information System (INIS)

    Ke, Yougang; Liu, Yachao; Zhou, Junxiao; Liu, Yuanyuan; Luo, Hailu; Wen, Shuangchun

    2016-01-01

    In the optical system, most elements such as lens, prism, and optical fiber are made of silica glass. Therefore, integrating Pancharatnam-Berry phase elements into silica glass has potential applications in the optical system. In this paper, we take a lens, for example, which integrates a Pancharatnam-Berry phase lens into a conventional plano-convex lens. The spin states and positions of focal points can be modulated by controlling the polarization states of the incident beam. The proposed lens has a high transmission efficiency, and thereby acts as a simple and powerful tool to manipulate spin photons. Furthermore, the method can be conveniently extended to the optical fiber and laser cavity, and may provide a route to the design of the spin-photonic devices.

  2. Anatomical and functional outcomes following vitrectomy for dense vitreous hemorrhage related to Terson syndrome in children.

    Science.gov (United States)

    Sayman Muslubas, Isil; Karacorlu, Murat; Hocaoglu, Mumin; Ersoz, Mehmet Giray; Arf, Serra

    2018-03-01

    Our purpose was to assess anatomical and functional outcomes of vitrectomy in pediatric cases of Terson syndrome. A total of 11 eyes of seven children diagnosed with Terson syndrome secondary to traumatic brain injury and 17 eyes of 12 children diagnosed with Terson syndrome secondary to nontraumatic brain hemorrhage who had 20-gauge or 23-gauge pars plana or pars plicata vitrectomy were included in this retrospective study. The primary outcome was the change in visual acuity from the preoperative examination to postoperative final follow-up. Secondary outcomes were anatomic surgical success and postoperative complications. The mean time between diagnosis and surgery was 62 ± 35 days (range, 30-150), and the average age at the time of the surgery was 4.5 ± 6.4 years (range, 3 months to 17 years). The mean preoperative logarithm of the minimum angle of resolution (logMAR) (Snellen) best corrected visual acuity (BCVA) was 2.6 ± 0.7 (20/7260) (n = 9) and in the remaining 19 eyes it was recorded as noncentral, unsteady, nonmaintained fixation. The mean follow-up period was 50 ± 54 months (range, 12-192 months). At the last follow-up visit, the mean logMAR BCVA was 0.46 ± 0.6 (20/60) (n = 19) and in eight eyes it was recorded as fix-and-follow. One eye developed a retinal detachment 14 months after the first operation, and one eye developed an epiretinal membrane after 2 years. Anatomical success was recorded in all patients at the final visit. In children with massive vitreous hemorrhage secondary to Terson syndrome, vitrectomy is an effective procedure and offers a rapid visual improvement. Earlier surgical treatment prevents amblyopia and blood-related potential complications.

  3. Transthyretin Ala36Pro mutation in a Chinese pedigree of familial transthyretin amyloidosis with elevated vitreous and serum vascular endothelial growth factor.

    Science.gov (United States)

    Zou, Xuan; Dong, Fangtian; Zhang, Shuying; Tian, Rong; Sui, Ruifang

    2013-05-01

    The familial transthyretin (TTR) amyloidosis (FTA) demonstrates variable penetrance of clinical features associated with mutations in the plasma thyroid hormone-binding protein TTR gene. The purpose of this study was to assess the ocular features, to analyze vitreous and serum vascular endothelial growth factor (VEGF) levels, and to identify the genetic defect in a Chinese family with TTR FTA. The pedigree of interest was a three-generation family with eleven members. The primary ocular signs were vitreous opacities, beginning from the third or fourth decade, accompanied by retinal vasculitis, hemorrhages, and widespread pinpoint deposits in the peripheral retina. Two patients underwent vitrectomy with marked improvement of visual acuity postoperatively. Vitreous and serum samples for VEGF were analyzed with an enzyme-linked immunosorbent assay (ELISA). Forty-eight healthy adult volunteers were enrolled as a control group for the analysis of serum VEGF. Eight subjects who underwent vitrectomy for a macular epiretinal membrane or macular hole were enrolled as control for the analysis of vitreous VEGF. Both serum and vitreous VEGF levels of patients were raised compared to that of controls. Venous blood was collected from family members and the genomic DNA was extracted. All exons and exon-intron boundaries of the TTR gene were sequenced. A previously-described pathogenic transversion in exon 2 (c.G106C, p.Ala36Pro) was identified. Within this family eight individuals were confirmed as affected. In conclusion, a Chinese family with TTR Ala36Pro associated FTA is characterized by early ocular involvement. Widespread pinpoint lesions indicate RPE lesions caused by TTR deposition. FTA is associated with increased VEGF levels, both in serum and vitreous. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Provision of dosimeters by official monitoring services for eye lens dose estimation

    International Nuclear Information System (INIS)

    Engelhardt, J.; Martini, E.

    2013-01-01

    Recent epidemiological studies are implying that the radio sensitivity of the eye lens is much higher than supposed in the past. International recommendations and standards demand to lower down the annual limit of the eye lens organ dose to 20 mSv. Since about 10 years German monitoring services offer partial-body dosimeters fixed on the head or on glasses for monitoring the eye lens dose. These dosimeters are optimized to measure the (surface) personal dose equivalent H p (0,07) from 0,5 mSv up to 10 Sv, which clearly overestimate the organ dose of the eye lens. With special features like different calibrations partial-body dosimeters should be applicable for legal dosimetry to avoid the development of special H p (3) dosimeters. Accepting the right way for wearing these dosimeters it is important to get the right results. Practical experiences are shown with measuring results and the difficulties of rounding the exact measuring values to discrete dose steps. Closing this article we point to still missing legal basis and open questions regarding to type testing procedures. (orig.)

  5. [Representation and mathematical analysis of human crystalline lens].

    Science.gov (United States)

    Tălu, Stefan; Giovanzana, Stefano; Tălu, Mihai

    2011-01-01

    The surface of human crystalline lens can be described and analyzed using mathematical models based on parametric representations, used in biomechanical studies and 3D solid modeling of the lens. The mathematical models used in lens biomechanics allow the study and the behavior of crystalline lens on variables and complex dynamic loads. Also, the lens biomechanics has the potential to improve the results in the development of intraocular lenses and cataract surgery. The paper presents the most representative mathematical models currently used for the modeling of human crystalline lens, both optically and biomechanically.

  6. Development of Powerhouse Using Fresnel lens

    Directory of Open Access Journals (Sweden)

    Al-Dohani Nawar Saif

    2018-01-01

    Full Text Available Solar energy is an alternative source of renewable energy. Sultanate of Oman government showed initiation on utilization of solar energy for domestic and industrial applications. Fresnel lens is one of the methods to collect maximum energy by gathering heat of the sun in the concentrated form (using solar collectors. Earlier research work discloses that Fresnel lens gave better result in terms of power output and produces lower heat loss as compared to linear –parabolic solar collectors. In this work, development of a proto Fresnel lens power house was made to generate electricity. The focused heat from Fresnel lens was used to heat the molten salt in a heat exchanger to produce the steam. The generated steam was used to rotate the steam engine coupled to a generator. In the current work, a maximum power of 30 W was produced. In addition, comparative study was carried out regarding solar salts and heat exchanger materials to understand the Fresnel powerhouse performance. Overall the present study gave valuable information regarding usage of Fresnel lens for electricity generation in Oman.

  7. A lazy way to design infrared lens

    Science.gov (United States)

    Qiu, RongSheng; Wu, JianDong; Chen, LongJiang; Yu, Kun; Pang, HaoJun; Hu, BaiZhen

    2017-08-01

    We designed a compact middle-wave infrared (MWIR) lens with a large focal length ratio (about 1.5:1), used in the 3.7 to 4.8 μm range. The lens is consisted of a compact front group and a re-imaging group. Thanks to the compact front group configuration, it is possible to install a filter wheel mechanism in such a tight space. The total track length of the lens is about 50mm, which includes a 2mm thick protective window and a cold shield of 12mm. The full field of view of the lens is about 3.6°, and F number is less than 1.6, the image circle is about 4.6mm in diameter. The design performance of the lens reaches diffraction limitation, and doesn't change a lot during a temperature range of -40°C +60°C. This essay proposed a stepwise design method of infrared optical system guided by the qualitative approach. The method fully utilize the powerful global optimization ability, with a little effort to write code snippet in optical design software, frees optical engineer from tedious calculation of the original structure.

  8. TESS Lens-Bezel Assembly Modal Testing

    Science.gov (United States)

    Dilworth, Brandon J.; Karlicek, Alexandra

    2017-01-01

    The Transiting Exoplanet Survey Satellite (TESS) program, led by the Kavli Institute for Astrophysics and Space Research at the Massachusetts Institute of Technology (MIT) will be the first-ever spaceborne all-sky transit survey. MIT Lincoln Laboratory is responsible for the cameras, including the lens assemblies, detector assemblies, lens hoods, and camera mounts. TESS is scheduled to be launched in August of 2017 with the primary goal to detect small planets with bright host starts in the solar neighborhood, so that detailed characterizations of the planets and their atmospheres can be performed. The TESS payload consists of four identical cameras and a data handling unit. Each camera consists of a lens assembly with seven optical elements and a detector assembly with four charge-coupled devices (CCDs) including their associated electronics. The optical prescription requires that several of the lenses are in close proximity to a neighboring element. A finite element model (FEM) was developed to estimate the relative deflections between each lens-bezel assembly under launch loads to predict that there are adequate clearances preventing the lenses from making contact. Modal tests using non-contact response measurements were conducted to experimentally estimate the modal parameters of the lens-bezel assembly, and used to validate the initial FEM assumptions. Key Words Non-contact measurements, modal analysis, model validation

  9. Assessment of the effect of intravitreal triamcinolone acetonide on the chorioretinal and vitreous inflammatory reaction to cryotherapy in rabbits

    Directory of Open Access Journals (Sweden)

    Eugênio Santana de Figueirêdo

    2012-10-01

    Full Text Available PURPOSE: To evaluate the inflammatory response in the choroid, retina and vitreous in rabbit eyes underwent cryotherapy followed by intravitreal triamcinolone acetonide and to compare with those underwent cryotherapy followed by intravitreal injection of saline solution. METHODS: This is a prospective case-control study. Surgical procedures were performed in eleven rabbits. Two animals were excluded because they did not complete the postoperative period or had intraoperative or postoperative complications. All rabbits underwent superior temporal peritomy and transscleralcryotherapy in both eyes. After cryotherapy, animals received intravitreal injection of triamcinolone acetonide in one eye and saline solution in the fellow eye. Animals were sacrificed seven days after the procedure and their eyes were enucleated. Histological sections of eyeballs were prepared and the vitreous humor was aspirated. The count of inflammatory cells was performed by light microscopy. RESULTS: Histological sections of both eyes of nine rabbits were analyzed. Inflammatory cells were found only in the choroid. There was no statistically significant difference in the number of inflammatory cells between the two groups, regardless of cell type analyzed. CONCLUSION: This study showed no statistically significant difference between the use or absence of intravitreal triamcinolone acetonide in the inflammatory response to cryotherapy in rabbit eyes. Studies with larger samples are needed to confirm the trend of this paper.

  10. Comparison of two Nd:YAG laser posterior capsulotomy: cruciate pattern vs circular pattern with vitreous strand cutting.

    Science.gov (United States)

    Kim, Jin-Soo; Choi, Jung Yeol; Kwon, Ji-Won; Wee, Won Ryang; Han, Young Keun

    2018-01-01

    To investigate the effects and safety of neodymium: yttrium-aluminium-garnet (Nd:YAG) laser posterior capsulotomy with vitreous strand cutting. A total of 40 eyes of 37 patients with symptomatic posterior capsular opacity (PCO) were included in this prospective randomized study and were randomly subjected to either cruciate pattern or round pattern Nd:YAG posterior capsulotomy with vitreous strand cutting (modified round pattern). The best corrected visual acuity (BCVA), intraocular pressure (IOP), refractive error, endothelial cell count (ECC), anterior segment parameters, including anterior chamber depth (ACD) and anterior chamber angle (ACA) were measured before and 1mo after the laser posterior capsulotomy. In both groups, the BCVA improved significantly ( P <0.001 for the modified round pattern group, P =0.001 for the cruciate pattern group); the IOP and ECC did not significantly change. The ACD significantly decreased ( P <0.001 for both) and the ACA significantly increased ( P =0.001 for the modified round pattern group and P =0.034 for the cruciate group). The extent of changes in these parameters was not significantly different between the groups. Modified round pattern Nd:YAG laser posterior capsulotomy is an effective and safe method for the treatment of PCO. This method significantly changes the ACD and ACA, but the change in refraction is not significant. Modified round pattern Nd:YAG laser posterior capsulotomy can be considered a good alternative procedure in patients with symptomatic PCO.

  11. Comparison of two Nd:YAG laser posterior capsulotomy: cruciate pattern vs circular pattern with vitreous strand cutting

    Directory of Open Access Journals (Sweden)

    Jin-Soo Kim

    2018-02-01

    Full Text Available AIM: To investigate the effects and safety of neodymium: yttrium-aluminium-garnet (Nd:YAG laser posterior capsulotomy with vitreous strand cutting METHODS: A total of 40 eyes of 37 patients with symptomatic posterior capsular opacity (PCO were included in this prospective randomized study and were randomly subjected to either cruciate pattern or round pattern Nd:YAG posterior capsulotomy with vitreous strand cutting (modified round pattern. The best corrected visual acuity (BCVA, intraocular pressure (IOP, refractive error, endothelial cell count (ECC, anterior segment parameters, including anterior chamber depth (ACD and anterior chamber angle (ACA were measured before and 1mo after the laser posterior capsulotomy. RESULTS: In both groups, the BCVA improved significantly (P<0.001 for the modified round pattern group, P=0.001 for the cruciate pattern group; the IOP and ECC did not significantly change. The ACD significantly decreased (P<0.001 for both and the ACA significantly increased (P=0.001 for the modified round pattern group and P=0.034 for the cruciate group. The extent of changes in these parameters was not significantly different between the groups. CONCLUSION: Modified round pattern Nd:YAG laser posterior capsulotomy is an effective and safe method for the treatment of PCO. This method significantly changes the ACD and ACA, but the change in refraction is not significant. Modified round pattern Nd:YAG laser posterior capsulotomy can be considered a good alternative procedure in patients with symptomatic PCO.

  12. Vitrectomía pars plana y reimplante de lente intraocular en surco Pars plana vitrectomy and intraocular lens repositioning in the sulcus

    Directory of Open Access Journals (Sweden)

    Alejandro Guerra García

    2010-01-01

    Full Text Available Se presentó un caso de lente intraocular luxado a vítreo en paciente con conteo bajo de células endoteliales e intolerancia a lentes de contacto. Se practicó vitrectomía pars plana con reimplante de lente en surco ciliar con el objetivo de demostrar la fiabilidad de la técnica para casos que presenten condiciones adecuadas y situaciones especiales. Se revisó la bibliografía para conocer las tendencias actuales con respecto al manejo de esta patología. El paciente alcanzó una agudeza visual de 20/30. El lente permaneció estable en el surco 3 meses después de practicada la vitrectomía. El manejo de esta entidad debe ser personalizado. La técnica utilizada debe ser siempre la primera opción de tratamiento y parece ser segura en casos cuidadosamente escogidos.A case of dislocated intraocular lens moved to the vitreous cavity in a patient with low endothelial cell count and contact lens intolerance was reported. A pars plana vitrectomy with lens repositioning was performed to demonstrate the safety of this technique for some special cases under adequate conditions. The literature was reviewed to learn about the current management of this pathology. Finally, patient's best visual acuity was 20/30. The stability of the lens was confirmed three month l after the vitrectomy. Management of this disorder should be customized. This technique should be considered as the first option of treatment and seems to be safe in selected cases.

  13. Terahertz lens made out of natural stone.

    Science.gov (United States)

    Han, Daehoon; Lee, Kanghee; Lim, Jongseok; Hong, Sei Sun; Kim, Young Kie; Ahn, Jaewook

    2013-12-20

    Terahertz (THz) time-domain spectroscopy probes the optical properties of naturally occurring solid aggregates of minerals, or stones, in the THz frequency range. Refractive index and extinction coefficient measurement reveals that most natural stones, including mudstone, sandstone, granite, tuff, gneiss, diorite, slate, marble, and dolomite, are fairly transparent for THz frequency waves. Dolomite in particular exhibits a nearly uniform refractive index of 2.7 over the broad frequency range from 0.1 to 1 THz. The high index of refraction allows flexibility in lens designing with a shorter accessible focal length or a thinner lens with a given focal length. Good agreement between the experiment and calculation for the THz beam profile confirms that dolomite has high homogeneity as a lens material, suggesting the possibility of using natural stones for THz optical elements.

  14. Catadioptric aberration correction in cathode lens microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tromp, R.M. [IBM T.J. Watson Research Center, PO Box 218, Yorktown Heights, NY 10598 (United States); Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Niels Bohrweg 2, 2333 CA Leiden (Netherlands)

    2015-04-15

    In this paper I briefly review the use of electrostatic electron mirrors to correct the aberrations of the cathode lens objective lens in low energy electron microscope (LEEM) and photo electron emission microscope (PEEM) instruments. These catadioptric systems, combining electrostatic lens elements with a reflecting mirror, offer a compact solution, allowing simultaneous and independent correction of both spherical and chromatic aberrations. A comparison with catadioptric systems in light optics informs our understanding of the working principles behind aberration correction with electron mirrors, and may point the way to further improvements in the latter. With additional developments in detector technology, 1 nm spatial resolution in LEEM appears to be within reach. - Highlights: • The use of electron mirrors for aberration correction in LEEM/PEEM is reviewed. • A comparison is made with similar systems in light optics. • Conditions for 1 nm spatial resolution are discussed.

  15. Freeform micromachining of an infrared Alvarez lens

    Science.gov (United States)

    Smilie, Paul J.; Dutterer, Brian S.; Lineberger, Jennifer L.; Davies, Matthew A.; Suleski, Thomas J.

    2011-02-01

    In 1967, Luis Alvarez introduced a novel concept for a focusing lens whereby two transmitting elements with cubic polynomial surfaces yield a composite lens of variable focal length with small lateral shifts. Computer simulations have demonstrated the behavior of these devices, but fabricating the refractive cubic surfaces of the types needed with adequate precision and depth modulation has proven to be challenging using standard methods, and, to the authors' knowledge, Alvarez lens elements have not been previously machined in infrared materials. Recent developments in freeform diamond machining capability have enabled the fabrication of such devices. In this paper, we discuss the fabrication of freeform refractive Alvarez elements in germanium using diamond micro-milling on a five-axis Moore Nanotech® 350FG Freeform Generator. Machining approaches are discussed, and measurements of surface figure and finish are presented. Initial experimental tests of optical performance are also discussed.

  16. Invited review article: the electrostatic plasma lens.

    Science.gov (United States)

    Goncharov, Alexey

    2013-02-01

    The fundamental principles, experimental results, and potential applications of the electrostatic plasma lens for focusing and manipulating high-current, energetic, heavy ion beams are reviewed. First described almost 50 years ago, this optical beam device provides space charge neutralization of the ion beam within the lens volume, and thus provides an effective and unique tool for focusing high current beams where a high degree of neutralization is essential to prevent beam blow-up. Short and long lenses have been explored, and a lens in which the magnetic field is provided by rare-earth permanent magnets has been demonstrated. Applications include the use of this kind of optical tool for laboratory ion beam manipulation, high dose ion implantation, heavy ion accelerator injection, in heavy ion fusion, and other high technology.

  17. Characterization of lens based photoacoustic imaging system

    Directory of Open Access Journals (Sweden)

    Kalloor Joseph Francis

    2017-12-01

    Full Text Available Some of the challenges in translating photoacoustic (PA imaging to clinical applications includes limited view of the target tissue, low signal to noise ratio and the high cost of developing real-time systems. Acoustic lens based PA imaging systems, also known as PA cameras are a potential alternative to conventional imaging systems in these scenarios. The 3D focusing action of lens enables real-time C-scan imaging with a 2D transducer array. In this paper, we model the underlying physics in a PA camera in the mathematical framework of an imaging system and derive a closed form expression for the point spread function (PSF. Experimental verification follows including the details on how to design and fabricate the lens inexpensively. The system PSF is evaluated over a 3D volume that can be imaged by this PA camera. Its utility is demonstrated by imaging phantom and an ex vivo human prostate tissue sample.

  18. Characterization of lens based photoacoustic imaging system.

    Science.gov (United States)

    Francis, Kalloor Joseph; Chinni, Bhargava; Channappayya, Sumohana S; Pachamuthu, Rajalakshmi; Dogra, Vikram S; Rao, Navalgund

    2017-12-01

    Some of the challenges in translating photoacoustic (PA) imaging to clinical applications includes limited view of the target tissue, low signal to noise ratio and the high cost of developing real-time systems. Acoustic lens based PA imaging systems, also known as PA cameras are a potential alternative to conventional imaging systems in these scenarios. The 3D focusing action of lens enables real-time C-scan imaging with a 2D transducer array. In this paper, we model the underlying physics in a PA camera in the mathematical framework of an imaging system and derive a closed form expression for the point spread function (PSF). Experimental verification follows including the details on how to design and fabricate the lens inexpensively. The system PSF is evaluated over a 3D volume that can be imaged by this PA camera. Its utility is demonstrated by imaging phantom and an ex vivo human prostate tissue sample.

  19. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2016-12-19

    The gain of an antenna can be enhanced through the integration of a lens, however this technique has traditionally been restricted to planar antennas due to fabrication limitations of standard manufacturing processes. Here, with a unique combination of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a Fresnel lens enhances the gain of a 2-turn helix by around 4.6 dB giving a peak gain of about 12.9 dBi at 8.8 GHz.

  20. Analytic models of plausible gravitational lens potentials

    International Nuclear Information System (INIS)

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune

    2009-01-01

    Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sérsic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sérsic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses

  1. Photonic crystal based polarization insensitive flat lens

    International Nuclear Information System (INIS)

    Turduev, M; Bor, E; Kurt, H

    2017-01-01

    The paper proposes a new design of an inhomogeneous artificially created photonic crystal lens structure consisting of annular dielectric rods to efficiently focus both transverse electric and transverse magnetic polarizations of light into the same focal point. The locations of each individual cell that contains the annular dielectric rods are determined according to a nonlinear distribution function. The inner and outer radii of the annular photonic dielectric rods are optimized with respect to the polarization insensitive frequency response of the transmission spectrum of the lens structure. The physical background of the polarization insensitive focusing mechanism is investigated in both spatial and frequency domains. Moreover, polarization independent wavefront transformation/focusing has been explored in detail by investigating the dispersion relation of the structure. Corresponding phase index distribution of the lens is attained for polarization insensitive normalized frequency range of a / λ   =  0.280 and a / λ   =  0.300, where a denotes the lattice constant of the designed structure and λ denotes the wavelength of the incident light. We show the wave transformation performance and focal point movement dynamics for both polarizations of the lens structure by specially adjusting the length of the structure. The 3D finite-difference time domain numerical analysis is also performed to verifiy that the proposed design is able to focus the wave regardless of polarization into approximately the same focal point (difference between focal distances of both polarizations stays below 0.25 λ ) with an operating bandwidth of 4.30% between 1476 nm and 1541 nm at telecom wavelengths. The main superiorities of the proposed lens structure are being all dielectric and compact, and having flat front and back surfaces, rendering the proposed lens design more practical in the photonic integration process in various applications such as optical switch

  2. Effect of infrared radiation on the lens

    Directory of Open Access Journals (Sweden)

    Aly Eman

    2011-01-01

    Full Text Available Background: Infrared (IR radiation is becoming more popular in industrial manufacturing processes and in many instruments used for diagnostic and therapeutic application to the human eye. Aim : The present study was designed to investigate the effect of IR radiation on rabbit′s crystalline lens and lens membrane. Materials and Methods: Fifteen New Zealand rabbits were used in the present work. The rabbits were classified into three groups; one of them served as control. The other two groups were exposed to IR radiation for 5 or 10 minutes. Animals from these two irradiated groups were subdivided into two subgroups; one of them was decapitated directly after IR exposure, while the other subgroup was decapitated 1 hour post exposure. IR was delivered from a General Electric Lamp model 250R 50/10, placed 20 cm from the rabbit and aimed at each eye. The activity of Na + -K + ATPase was measured in the lens membrane. Soluble lens proteins were extracted and the following measurements were carried out: estimation of total soluble protein, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE and Fourier transform infrared (FTIR spectroscopy. For comparison between multiple groups, analysis of variance was used with significance level set at P < 0.001. Results: The results indicated a change in the molecular weight of different lens crystalline accompanied with changes in protein backbone structure. These changes increased for the groups exposed to IR for 10 minutes. Moreover, the activity of Na + -K + ATPase significantly decreased for all groups. Conclusions: The protein of eye lens is very sensitive to IR radiation which is hazardous and may lead to cataract.

  3. ANALYTICAL SOLUTIONS OF SINGULAR ISOTHERMAL QUADRUPOLE LENS

    International Nuclear Information System (INIS)

    Chu Zhe; Lin, W. P.; Yang Xiaofeng

    2013-01-01

    Using an analytical method, we study the singular isothermal quadrupole (SIQ) lens system, which is the simplest lens model that can produce four images. In this case, the radial mass distribution is in accord with the profile of the singular isothermal sphere lens, and the tangential distribution is given by adding a quadrupole on the monopole component. The basic properties of the SIQ lens have been studied in this Letter, including the deflection potential, deflection angle, magnification, critical curve, caustic, pseudo-caustic, and transition locus. Analytical solutions of the image positions and magnifications for the source on axes are derived. We find that naked cusps will appear when the relative intensity k of quadrupole to monopole is larger than 0.6. According to the magnification invariant theory of the SIQ lens, the sum of the signed magnifications of the four images should be equal to unity, as found by Dalal. However, if a source lies in the naked cusp, the summed magnification of the left three images is smaller than the invariant 1. With this simple lens system, we study the situations where a point source infinitely approaches a cusp or a fold. The sum of the magnifications of the cusp image triplet is usually not equal to 0, and it is usually positive for major cusps while negative for minor cusps. Similarly, the sum of magnifications of the fold image pair is usually not equal to 0 either. Nevertheless, the cusp and fold relations are still equal to 0 in that the sum values are divided by infinite absolute magnifications by definition.

  4. Intraocular Lens Calcification; a Clinicopathologic Report

    Directory of Open Access Journals (Sweden)

    Mozhgan Rezaei-Kanavi

    2009-04-01

    Full Text Available

    PURPOSE: To describe the clinical and pathological features of a case of hydrogel intraocular lens (IOL calcification. CASE REPORT: A 48-year-old man underwent explantation of a single-piece hydrophilic acrylic intraocular lens in his left eye because of decreased visual acuity and milky white opalescence of the IOL. The opacified lens was exchanged uneventfully with a hydrophobic acrylic IOL. Gross examination of the explanted IOL disclosed opacification of the optic and haptics. Full-thickness sections of the lens optic were stained with hematoxylin and eosin (H&E, von Kossa and Gram Tworts'. Microscopic examination of the sections revealed fine and diffuse basophilic granular deposits of variable size within the lens optic parallel to the lens curvature but separated from the surface by a moderately clear zone. The deposits were of high calcium content as evident by dark brown staining with von Kossa. Gram Tworts' staining disclosed no microorganisms. CONCLUSION: This report further contributes to the existing literature on hydrogel IOL calcification.

  5. Comparison of clear lens extraction and collamer lens implantation in high myopia

    Directory of Open Access Journals (Sweden)

    Ahmed M Emarah

    2010-05-01

    Full Text Available Ahmed M Emarah, Mostafa A El-Helw, Hazem M YassinCairo University, Cairo, EgyptAim: To compare the outcomes of clear lens extraction and collamer lens implantation in high myopia.Patients and methods: Myopic patients younger than 40 years old with more than 12 diopters of myopia or who were not fit for laser-assisted in situ keratomileusis were included. Group 1 comprised patients undergoing clear lens extraction and Group 2 patients received the Visian implantable collamer lens. Outcome and complications were evaluated.Results: Postoperative best corrected visual acuity was -0.61 ± 0.18 in Group 1 and 0.79 ± 0.16 in Group 2. In Group 1, 71.4% achieved a postoperative uncorrected visual acuity better than the preoperative best corrected visual acuity, while only 51.8% patients achieved this in Group 2. Intraocular pressure decreased by 12.55% in Group 1, and increased by 15.11% in Group 2. Corneal endothelial cell density decreased by 4.47% in Group 1 and decreased by 5.67% in Group 2. Posterior capsule opacification occurred in Group 1. In Group 2, lens opacification occurred in 11.11%, significant pigment dispersion in 3.7%, and pupillary block glaucoma in 3.7%.Conclusion: Clear lens extraction presents less of a financial load up front, and less likelihood of the need for a secondary intervention in the future. Clear lens extraction is a more viable solution in developing countries with limited financial resources.Keywords: clear lens extraction, implantable collamer lens, myopia

  6. Liquid lens: advances in adaptive optics

    Science.gov (United States)

    Casey, Shawn Patrick

    2010-12-01

    'Liquid lens' technologies promise significant advancements in machine vision and optical communications systems. Adaptations for machine vision, human vision correction, and optical communications are used to exemplify the versatile nature of this technology. Utilization of liquid lens elements allows the cost effective implementation of optical velocity measurement. The project consists of a custom image processor, camera, and interface. The images are passed into customized pattern recognition and optical character recognition algorithms. A single camera would be used for both speed detection and object recognition.

  7. Pulse transformer for the AA lithium lens

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The antiprotons emanating from the target were initially focused by a magnetic horn. Later on, a Li-lens was used during operation for the SPS collider, until 1992. A Li-rod (130 mm long, 34 mm in diameter) constituted the secondary of a 1:23 pulse-transformer. The half-sine pulse rose to 1000 kA in 900 microsec. The angular acceptance was 95 mrad. In operation after 1992, for LEAR only, a more modest Li-lens was used (155 mm long, diameter 20 mm, 480 kA, risetime 240 microsec, angular acceptance 75 mrad).

  8. Herniation of the anterior lens capsule

    Directory of Open Access Journals (Sweden)

    Pereira Nolette

    2007-01-01

    Full Text Available Herniation of the anterior lens capsule is a rare abnormality in which the capsule bulges forward in the pupillary area. This herniation can be mistaken for an anterior lenticonus where both the capsule and the cortex bulge forward. The exact pathology behind this finding is still unclear. We report the clinical, ultrasound biomicroscopy (UBM and histopathological findings of a case of herniation of the anterior lens capsule. UBM helped to differentiate this entity from anterior lenticonus. Light microscopy revealed capsular splitting suggestive of capsular delamination and collection of fluid (aqueous in the area of herniation giving it a characteristic appearance.

  9. Dose conversion coefficients for photon exposure of the human eye lens

    Science.gov (United States)

    Behrens, R.; Dietze, G.

    2011-01-01

    In recent years, several papers dealing with the eye lens dose have been published, because epidemiological studies implied that the induction of cataracts occurs even at eye lens doses of less than 500 mGy. Different questions were addressed: Which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens? Is a new definition of the dose quantity Hp(3) based on a cylinder phantom to represent the human head necessary? Are current conversion coefficients from fluence to equivalent dose to the lens sufficiently accurate? To investigate the latter question, a realistic model of the eye including the inner structure of the lens was developed. Using this eye model, conversion coefficients for electrons have already been presented. In this paper, the same eye model—with the addition of the whole body—was used to calculate conversion coefficients from fluence (and air kerma) to equivalent dose to the lens for photon radiation from 5 keV to 10 MeV. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are similar between 40 keV and 1 MeV and lower by up to a factor of 5 and 7 for photon energies at about 10 keV and 10 MeV, respectively. Above 1 MeV, the new values (calculated without kerma approximation) should be applied in pure photon radiation fields, while the values adopted by the ICRP in 1996 (calculated with kerma approximation) should be applied in case a significant contribution from secondary electrons originating outside the body is present.

  10. Immunochemical analyses of soluble lens proteins in some marine fishes

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    Soluble eye lens proteins of 10 fishes, belonging to the families Clupeidae, Hemirhamphidae, Lactaridae, Scombridae, Stromatidae, Psettodidae, Bothidae and Soleidae were studied by immunoelectrophoresis using the lens antiserum of Sardinella...

  11. Chapter 03: Correct use of a hand lens

    Science.gov (United States)

    Alex Wiedenhoeft

    2011-01-01

    A hand lens is a powerful tool for the identification of wood, but like all tools it must be used correctly to take full advantage of its powers. The hand lens has two main parts, a lens that magnifies the object of interest (generally we use 10X or 14X lenses in wood identification; a 14X lens is recommended for use with this manual) and a housing to hold and protect...

  12. 21 CFR 886.1405 - Ophthalmic trial lens set.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens set. 886.1405 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1405 Ophthalmic trial lens set. (a) Identification. An ophthalmic trial lens set is a device that is a set of lenses of various dioptric powers...

  13. 21 CFR 886.1420 - Ophthalmic lens gauge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic lens gauge. 886.1420 Section 886.1420...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1420 Ophthalmic lens gauge. (a) Identification. An ophthalmic lens gauge is a calibrated device intended to manually measure the curvature of a...

  14. 21 CFR 886.1410 - Ophthalmic trial lens clip.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens clip. 886.1410 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1410 Ophthalmic trial lens clip. (a) Identification. An ophthalmic trial lens clip is a device intended to hold prisms, spheres, cylinders, or...

  15. 21 CFR 886.1380 - Diagnostic condensing lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic condensing lens. 886.1380 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1380 Diagnostic condensing lens. (a) Identification. A diagnostic condensing lens is a device used in binocular indirect ophthalmoscopy (a procedure...

  16. 21 CFR 886.1415 - Ophthalmic trial lens frame.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic trial lens frame. 886.1415 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1415 Ophthalmic trial lens frame. (a) Identification. An opthalmic trial lens frame is a mechanical device intended to hold trial lenses for vision...

  17. In vivo study of lens regeneration in Rana cyanophlyctis under ...

    African Journals Online (AJOL)

    SAM

    2014-03-12

    Mar 12, 2014 ... enhanced the percentage lens regeneration not only in young tadpoles but also in froglets. Lens regeneration ability ... Influence of vitamin A and ascorbic acid on lens regeneration in young, mature tadpoles and froglets of the frog Rana cyanophlyctis. Group .... ingested by macrophages. Dorsal iris cells ...

  18. Potential pre-cataractous markers induced by low-dose radiation effects in cultured human lens cells

    Science.gov (United States)

    Blakely, E.; McNamara, M.; Bjornstad, K.; Chang, P.

    The human lens is one of the most radiosensitive organs of the body. Cataract, the opacification of the lens, is a late-appearing response to radiation damage. Recent evidence indicates that exposure to relatively low doses of space radiation are associated with an increased incidence and early appearance of human cataracts (Cucinotta et al., Radiat. Res. 156:460-466, 2001). Basic research in this area is needed to integrate the early responses of various late-responding tissues into our understanding and estimation of radiation risk for space travel. In addition, these studies may contribute to the development of countermeasures for the early lenticular changes, in order to prevent the late sequelae. Radiation damage to the lens is not life threatening but, if severe, can affect vision unless surgically corrected with synthetic lens replacement. The lens, however, may be a sensitive detector of radiation effects for other cells of ectodermal origin in the body for which there are not currently clear endpoints of low-dose radiation effects. We have investigated the dose-dependent expression of several radiation-responsive endpoints using our in vitro model of differentiating human lens epithelial cells (Blakely et al., Investigative Ophthalmology &Visual Sciences, 41(12):3898-3907, 2000). We have investigated radiation effects on several gene families that include, or relate to, DNA damage, cytokines, cell-cycle regulators, cell adhesion molecules, cell cytoskeletal function and apoptotic cell death. In this paper we will summarize some of our dose-dependent data from several radiation types, and describe the model of molecular and cellular events that we believe may be associated with precataractous events in the human lens after radiation exposure. This work was supported by NASA Grant #T-965W.

  19. Vitreous advanced glycation endproducts and alpha-dicarbonyls in retinal detachment patients with type 2 diabetes mellitus and non-diabetic controls

    NARCIS (Netherlands)

    Fokkens, Bernardina T.; Mulder, Douwe J.; Schalkwijk, Casper G.; Scheijen, Jean L.; Smit, Andries J.; Los, Leonoor I.

    2017-01-01

    Purpose Advanced glycation endproducts (AGEs) and their precursors alpha-dicarbonyls are implicated in the progression of diabetic retinopathy. The purpose of this study was to assess AGEs and a-dicarbonyls in the vitreous of patients with type 2 diabetes mellitus (T2DM) with early stages or absence

  20. PREPARATION AND CHARACTERIZATION OF IRON THIN FILM ELECTRODEPOSED ON A VITREOUS CARBON ELECTRODE IN AQUEOUS AND ORGANIC MEDIA: A COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    A LOUNAS

    2010-06-01

    studied on a vitreous carbon electrode in various aqueous and organic media. The deposit of iron was studied by cyclic voltammetry; the quantity of iron deposited was determined by integration of the cathodic and anodic peaks of Fe (0 and Fe (II of the various media.

  1. Prostaglandin E2 Levels of Aqueous and Vitreous Humor in Ketorolac 0.4% and Nepafenac 0.1% Administered Healthy Rabbits.

    Science.gov (United States)

    Acar, Ugur; Acar, Damla Erginturk; Tanriverdi, Cafer; Acar, Mutlu; Ozdemir, Ozdemir; Erikci, Acelya; Ornek, Firdevs

    2017-06-01

    To compare the lowering effects of ketorolac 0.4% and nepafenac 0.1% on aqueous and vitreous humor prostaglandin E 2 (PGE 2 ) levels in rabbits. Ketorolac and nepafenac ophthalmic solutions were administered to the right eyes of 24 healthy rabbits after randomized division into two groups. The left eyes of these rabbits were considered as controls for the two groups. On the 4th day of the experiment, the samples were taken from the aqueous and vitreous humors of the rabbits bilaterally, and PGE 2 levels were measured by an enzyme immune assay kit. Ketorolac and nepafenac achieved a statistically significant decrease (phumor (6.58 ± 4.62 and 9.83 ± 4.55 pg/mL, respectively). Both ketorolac and nepafenac inhibited PGE 2 levels in both the aqueous and vitreous humors of rabbits. Although PGE 2 -lowering effects were similar in the aqueous humor, nepafenac seemed to be more potent than ketorolac in the vitreous humor.

  2. Safety results of two phase III trials of an intravitreous injection of highly purified ovine hyaluronidase (Vitrase) for the management of vitreous hemorrhage

    NARCIS (Netherlands)

    Kuppermann, Baruch D.; Thomas, Edgar L.; de Smet, Marc D.; Grillone, Lisa R.

    2005-01-01

    PURPOSE: To evaluate the safety of intravitreous ovine hyaluronidase for the management of vitreous hemorrhage. DESIGN: Two prospective, randomized, placebo-controlled, double-masked studies. Pooled efficacy data are presented in a companion article in this issue of The Journal. METHODS: Subjects

  3. Vitrectorhexis and lens aspiration with posterior chamber intraocular lens implantation in spherophakia.

    Science.gov (United States)

    Al-Haddad, Christiane; Khatib, Lama

    2012-07-01

    We describe a technique that uses the vitrector to perform successful lens aspiration and posterior chamber intraocular lens (IOL) implantation in children with spherophakia and anterior lens subluxation. After an anterior chamber maintainer is placed, the ocutome is introduced through a limbal incision to perform a circular vitrectorhexis to avoid excessive manipulation of the unstable lens followed by gentle cortex aspiration. A foldable IOL is injected into the sulcus (3-piece IOL) or bag (1-piece IOL) if the capsule is sufficiently stable. Through a pars plana incision, the ocutome is then used to perform a posterior capsulotomy to prevent late posterior capsule opacification. In our patient, sulcus IOL placement was more stable than in-the-bag placement. Neither author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  4. 3D printed helical antenna with lens

    KAUST Repository

    Farooqui, Muhammad Fahad; Shamim, Atif

    2016-01-01

    of 3D and 2D inkjet printing of dielectric and metallic inks respectively, we demonstrate a Fresnel lens that has been monolithically integrated to a non-planar antenna (helix) for the first time. Antenna measurements show that the integration of a

  5. Corneal ring infiltration in contact lens wearers

    Directory of Open Access Journals (Sweden)

    Seyed Ali Tabatabaei

    2017-01-01

    Full Text Available To report a case of atypical sterile ring infiltrates during wearing soft silicone hydrogel contact lens due to poor lens care. A 29-year-old woman presented with complaints of pain, redness, and morning discharge. She was wearing soft silicone hydrogel contact lens previously; her current symptoms began 1 week before presentation. On examination, best-corrected visual acuity was 20/40 in that eye. Slit-lamp examination revealed dense, ring-shaped infiltrate involving both the superficial and deep stromal layers with lucid interval to the limbus, edema of the epithelium, epithelial defect, and vascularization of the superior limbus. Cornea-specific in vivo laser confocal microscopy (Heidelberg Retina Tomograph 2 Rostock Cornea Module, HRT 2-RCM, Heidelberg Engineering GmbH, Dossenheim, Germany revealed Langerhans cells and no sign of Acanthamoeba or fungal features, using lid scraping and anti-inflammatory drops; her vision completely recovered. We reported an atypical case of a sterile corneal ring infiltrate associated with soft contact lens wearing; smear, culture, and confocal microscopy confirmed a sterile inflammatory reaction.

  6. Surgical treatment of hereditary lens subluxations.

    Science.gov (United States)

    Ozdek, Sengul; Sari, Ayca; Bilgihan, Kamil; Akata, Fikret; Hasanreisoglu, Berati

    2002-01-01

    To evaluate the effectiveness and results of pars plana vitreolensectomy approach with transscleral fixation of intraocular lens in hereditary lens subluxations. Fifteen eyes of 9 consecutive patients with a mean age of 12.8+/-6.2 years (6-26 years) with hereditary lens subluxation were operated on and the results were evaluated in a prospective study. Surgery was considered if best spectacle corrected visual acuity (BSCVA) was less than 20/70. All eyes underwent a 2-port pars plana vitreolensectomy and transscleral fixation of an intraocular lens (IOL). The mean follow-up period was 12.6+/-7.5 months (6-22 months). There was no major intraoperative complication. Preoperatively, 8 eyes (53.3%) had a BSCVA of counting fingers (CF) and 7 eyes (46.6%) had a BSCVA of 20/200 to 20/70. Postoperatively, 14 eyes (93.3%) had a BSCVA of 20/50 or better. None of the patients had IOL decentration or intraocular pressure (IOP) increase during the follow-up period. There was a macular hole formation in 1 eye postoperatively. The early results of pars plana vitreolensectomy with IOL implantation using scleral fixation technique had shown that it not only promises a rapid visual rehabilitation but it is also a relatively safe method. More serious complications, however, may occur in the long term.

  7. Lens Ray Diagrams with a Spreadsheet

    Science.gov (United States)

    González, Manuel I.

    2018-01-01

    Physicists create spreadsheets customarily to carry out numerical calculations and to display their results in a meaningful, nice-looking way. Spreadsheets can also be used to display a vivid geometrical model of a physical system. This statement is illustrated with an example taken from geometrical optics: images formed by a thin lens. A careful…

  8. Electronic states in a quantum lens

    International Nuclear Information System (INIS)

    Rodriguez, Arezky H.; Trallero-Giner, C.; Ulloa, S. E.; Marin-Antuna, J.

    2001-01-01

    We present a model to find analytically the electronic states in self-assembled quantum dots with a truncated spherical cap (''lens'') geometry. A conformal analytical image is designed to map the quantum dot boundary into a dot with semispherical shape. The Hamiltonian for a carrier confined in the quantum lens is correspondingly mapped into an equivalent operator and its eigenvalues and eigenfunctions for the corresponding Dirichlet problem are analyzed. A modified Rayleigh-Schro''dinger perturbation theory is presented to obtain analytical expressions for the energy levels and wave functions as a function of the spherical cap height b and radius a of the circular cross section. Calculations for a hard wall confinement potential are presented, and the effect of decreasing symmetry on the energy values and eigenfunctions of the lens-shape quantum dot is studied. As the degeneracies of a semicircular geometry are broken for b≠a, our perturbation approach allows tracking of the split states. Energy states and electronic wave functions with m=0 present the most pronounced influence on the reduction of the lens height. The method and expressions presented here can be straightforwardly extended to deal with more general Hamiltonians, including strains and valence-band coupling effects in Group III--V and Group II--VI self-assembled quantum dots

  9. Changes in monkey crystalline lens spherical aberration during simulated accommodation in a lens stretcher.

    Science.gov (United States)

    Maceo Heilman, Bianca; Manns, Fabrice; de Castro, Alberto; Durkee, Heather; Arrieta, Esdras; Marcos, Susana; Parel, Jean-Marie

    2015-02-10

    The purpose of this study was to quantify accommodation-induced changes in the spherical aberration of cynomolgus monkey lenses. Twenty-four lenses from 20 cynomolgus monkeys (Macaca fascicularis; 4.4-16.0 years of age; postmortem time 13.5 ± 13.0 hours) were mounted in a lens stretcher. Lens spherical aberration was measured in the unstretched (accommodated) and stretched (relaxed) states with a laser ray tracing system that delivered 51 equally spaced parallel rays along 1 meridian of the lens over the central 6-mm optical zone. A camera mounted below the lens was used to measure the ray height at multiple positions along the optical axis. For each entrance ray, the change in ray height with axial position was fitted with a third-order polynomial. The effective paraxial focal length and Zernike spherical aberration coefficients corresponding to a 6-mm pupil diameter were extracted from the fitted values. The unstretched lens power decreased with age from 59.3 ± 4.0 diopters (D) for young lenses to 45.7 ± 3.1 D for older lenses. The unstretched lens shifted toward less negative spherical aberration with age, from -6.3 ± 0.7 μm for young lenses to -5.0 ± 0.5 μm for older lenses. The power and spherical aberration of lenses in the stretched state were independent of age, with values of 33.5 ± 3.4 D and -2.6 ± 0.5 μm, respectively. Spherical aberration is negative in cynomolgus monkey lenses and becomes more negative with accommodation. These results are in good agreement with the predicted values using computational ray tracing in a lens model with a reconstructed gradient refractive index. The spherical aberration of the unstretched lens becomes less negative with age. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

  10. Method for producing an isoplanatic aspheric monofocal intraocular lens, and resul ting lens

    OpenAIRE

    Barbero, Sergio; Marcos, Susana; Dorronsoro, Carlos; Montejo, Javier; Salazar Salegui, Pedro

    2010-01-01

    [EN] The invention can be used to obtain isoplanatic aspheric mono focal intraocular lenses in a viewing range of up to 25° (preferably up to 10°). The method comprises the following steps: l. mathematical defmition of an aphakic eye model; 2. mathematical definition of an intraocular lens model; 3. mathematical defmition of the implantation of the lens; 4. mathematical defmition of the merit function; 5. definition of the contour conditions; 6. defmition of a measurement for charact...

  11. Properties of the cathode lens combined with a focusing magnetic/immersion-magnetic lens

    Czech Academy of Sciences Publication Activity Database

    Konvalina, Ivo; Müllerová, Ilona

    2011-01-01

    Roč. 645, č. 1 (2011), s. 55-59 ISSN 0168-9002 R&D Projects: GA ČR GAP102/10/1410; GA AV ČR IAA100650902; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : cathode lens * compound objective lens * aberration coefficients * spot size * field calculations Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.207, year: 2011

  12. FEA Analysis of AP-0 Target Hall Collection Lens (Current Design)

    International Nuclear Information System (INIS)

    Hurh, P.G.; Tang, Z.

    2001-01-01

    Collection Lens, this material is lithium (Li). The central conductor cylinder is a lithium cylinder 1 cm in radius and about 14 cm long. Figure 1 shows this cylinder in a cross-section view of the Collection Lens. Surrounding the central cylinder is a jacket of titanium alloy (6Al-4V ELI) called the septum. The septum's purpose is to contain the lithium against various thermal and magnetic forces while allowing cooling (melting point of Li is 180.5 C) by an annular water passage. The ends of the Li cylinder are bound by end windows made of beryllium (Be) and a thin titanium (ti) foil. The foil protects the Be from the corrosive effects of Li and the Be window provides the structural support. The two end windows sit in pockets in the ends of two larger steel cylinders or body halves. The body halves are separated from each other by ceramic spacers. The body halves, septum and end windows are connected to each other by nickel (Ni) seals which preserve the boundary of the lithium conductor. Force required to make these seals is provided by eight Ti 6Al-4V ELI tie rods which traverse the entire assembly. These tie rods also resist magnetic forces that attempt to separate the body halves during the current pulse. There are several insulating components that are used to isolate one side of the lens from the other and force the current through the central Li conductor. The volumes of Li at each end of the central conductor cylinder outside the septum but inside the body halves are called buffer volumes. These buffer volumes serve two roles. One, they provide a low resistance current path to the end of the central conductor cylinder. Two, they provide a volume for Li to expand into during the current pulse. For the latter it is assumed that magnetic forces and thermal strains will force lithium from the central cylinder and into the buffer volumes during the current pulse. There are several loads on the Lens that are developed during a current pulse. High magnetic loads act

  13. Pilot study of the dose in crystalline lens in the interventional radiology practice

    International Nuclear Information System (INIS)

    Castro, A.; Martinez, A.; Fernandez, A.; Molina, D.; Sanchez, L.; Diaz, A.

    2014-08-01

    The interventional radiology involves considerable exposure levels for the occupationally exposed personnel (OEP). The doses can encompass a wide range of values in dependence of the function that develops the personnel and the complexity of each procedure. In organs like the crystalline lens and skin values can be reached that imply the appearance of deterministic effects if is not fulfilled the appropriate measures of radiological protection. This has been demonstrated through multiple studies, among those that the retrospective study of damages in the crystalline lens and dose has been one of those most commented, known as RELID. The objective of that study was to examine the opacity prevalence in the crystalline lens in workers linked to the interventional cardiology and to correlate it with the occupational exposition. The obtained results contributed to that the ICRP recommend a new limit value of equivalent dose for crystalline lens of 20 mSv in one year. With the objective of analyzing the operational implications, in the radiological surveillance programs that they could originate with the new recommendations was developed a pilot study to evaluate the dose in crystalline lens in the OEP linked to the interventional radiology in a Cuban hospital. For this, an anthropomorphic mannequin RANDO-ALDERSON was used on which thermoluminescent dosimeters were placed below and above of the leaded apron and in different positions at level of the crystalline lens: above, below and to the sides of the leaded lenses that the personnel uses routinely. The mannequin was located on the same positions that occupy the main specialist that execute the procedure, as well as of the nurse to assist him. The measurements were made simulating the more representative procedures about complexity, duration time and exposure rate. The used dosimeters were RADOS model for whole body composed of two thermoluminescent detectors Gr-200 (LiF: Mg, Cu, P) to evaluate personal equivalent dose

  14. Preliminary Investigation of an Active PLZT Lens

    Science.gov (United States)

    Lightsey, W. D.; Peters, B. R.; Reardon, P. J.; Wong, J. K.

    2001-01-01

    The design, analysis and preliminary testing of a prototype Adjustable Focus Optical Correction Lens (AFOCL) is described. The AFOCL is an active optical component composed of solid state lead lanthanum-modified zirconate titanate (PLZT) ferroelectric ceramic with patterned indium tin oxide (ITO) transparent surface electrodes that modulate the refractive index of the PLZT to function as an electro-optic lens. The AFOCL was developed to perform optical re-alignment and wavefront correction to enhance the performance of Ultra-Lightweight Structures and Space Observatories (ULSSO). The AFOCL has potential application as an active optical component within a larger optical system. As such, information from a wavefront sensor would be processed to provide input to the AFOCL to drive the sensed wavefront to the desired shape and location. While offering variable and rapid focussing capability (controlled wavefront manipulation) similar to liquid crystal based spatial light modulators (SLM), the AFOCL offers some potential advantages because it is a solid-state, stationary, low-mass, rugged, and thin optical element that can produce wavefront quality comparable to the solid refractive lens it replaces. The AFOCL acts as a positive or negative lens by producing a parabolic phase-shift in the PLZT material through the application of a controlled voltage potential across the ITO electrodes. To demonstrate the technology, a 4 mm diameter lens was fabricated to produce 5-waves of optical power operating at 2.051 micrometer wavelength. Optical metrology was performed on the device to measure focal length, optical quality, and efficiency for a variety of test configurations. The data was analyzed and compared to theoretical data available from computer-based models of the AFOCL.

  15. Embodied female experience through the lens of imagination.

    Science.gov (United States)

    Green, Sharon R

    2010-06-01

    In 1971, I made a film entitled Self Portrait of a Nude Model Turned Cinematographer in which I explore the objectifying 'male' gaze on my body in contrast to the subjective lived experience of my body. The film was a radical challenge to the gaze that objectifies woman - and thus imprisons her - which had hitherto dominated narrative cinema. Since the objectification of women has largely excluded us from the privileged phallogocentric discourses, in this paper I hope to bring into the psychoanalytic dialogue a woman's lived experience. I will approach this by exploring how remembering this film has become a personally transformative experience as I look back on it through the lens of postmodern and feminist discourses that have emerged since it was made. In addition, I will explore how this process of imaginatively looking back on an artistic creation to generate new discourses in the present is similar to the transformative process of analysis. Lastly, I will present a clinical example, where my embodied countertransference response to a patient's subjection to the objectifying male gaze opens space for a new discourse about her body to emerge.

  16. PHYSICAL CHARACTERIZATION OF VITREOUS STATE LABORATORY AY102/C106 AND AZ102 HIGH LEVEL WASTE MELTER FEED SIMULANTS (U)

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E

    2005-03-31

    The objective of this task is to characterize and report specified physical properties and pH of simulant high level waste (HLW) melter feeds (MF) processed through the scaled melters at Vitreous State Laboratories (VSL). The HLW MF simulants characterized are VSL AZ102 straight hydroxide melter feed, VSL AZ102 straight hydroxide rheology adjusted melter feed, VSL AY102/C106 straight hydroxide melter feed, VSL AY102/C106 straight hydroxide rheology adjusted melter feed, and Savannah River National Laboratory (SRNL) AY102/C106 precipitated hydroxide processed sludge blended with glass former chemicals at VSL to make melter feed. The physical properties and pH were characterized using the methods stated in the Waste Treatment Plant (WTP) characterization procedure (Ref. 7).

  17. Elaboration of vitreous and vitrocrystalline basalt materials containing simulated radioactive ash wastes. Study of some physical properties and leaching behaviour

    International Nuclear Information System (INIS)

    Lebeau, M.J.

    1988-01-01

    This work is a preliminary study of a matrix for containment of incinerator ashes. Basalt presents a good capacity for ash incorporation (up to 50%), glasses obtained are homogeneous and the low viscosity at 1300 0 C allows an industrial preparation. Vitrocrystalline products have a dendritic texture which can be controlled by cooling rate and are composed of magnesioferrite, pyroxene, plagioclase and vitreous fraction depending on the filling material ratio. Uranium and thorium, for actinide simulation in ashes, are localized in the glass. Glass leaching decrease with ash content and the alteration film presents a better retention of some elements, such as uranium and thorium. Vitrocrystalline materials are less leachable than glasses. Interesting possibilities are shown for use of basalt as filling material in underground storage, since basalt decrease glass deterioration [fr

  18. Man-made vitreous fiber produced from incinerator ash using the thermal plasma technique and application as reinforcement in concrete.

    Science.gov (United States)

    Yang, Sheng-Fu; Wang, To-Mai; Lee, Wen-Cheng; Sun, Kin-Seng; Tzeng, Chin-Ching

    2010-10-15

    This study proposes using thermal plasma technology to treat municipal solid waste incinerator ashes. A feasible fiberization method was developed and applied to produce man-made vitreous fiber (MMVF) from plasma vitrified slag. MMVF were obtained through directly blending the oxide melt stream with high velocity compressed air. The basic technological characteristics of MMVF, including morphology, diameter, shot content, length and chemical resistance, are described in this work. Laboratory experiments were conducted on the fiber-reinforced concrete. The effects of fibrous content on compressive strength and flexural strength are presented. The experimental results showed the proper additive of MMVF in concrete can enhance its mechanical properties. MMVF products produced from incinerator ashes treated with the thermal plasma technique have great potential for reinforcement in concrete. 2010 Elsevier B.V. All rights reserved.

  19. Vitreous System Ag2O –ZnO–B2O3 Action Against Gram Negative Bacteria

    Directory of Open Access Journals (Sweden)

    Razvan Stefan

    2010-05-01

    Full Text Available In this work the ability of the system xAg2O  (100-x [45ZnO55B2O3] oxide glasses to inhibit the growth of bacteria Eschierchia coli, Pseudomonas and Salmonella was investigated. Using the diffusimetric method there were measured the diameters of inhibition, in order to classify the sensitivity of gram negative bacteria to oxide compounds containing silver, for their use as filters. Vitreous samples were processed as powders with grain between 45 and 75 m and less than 45 m for a large of contact area with the microorgansms and to make possible the study of biological effect of grain addiction. Action of the investigated oxide system against the gram negative bacteria is strictly related to the presence of silver oxide in glass composition.

  20. Gram negative bacteria and contact lens induced acute red eye

    Directory of Open Access Journals (Sweden)

    Sankaridurg Padmaja

    1996-01-01

    Full Text Available Two patients using hydrogel contact lenses on a daily wear schedule slept overnight with the lenses and woke up with a Contact Lens Induced Acute Red Eye (CLARE. The contact lenses recovered aseptically at the time of the event grew significant colonies of Pseudomonas aeruginosa and Aeromonas hydrophila in patient A and Pseudomonas aeruginosa and Serratia liquefaciens from patient B. Similar organisams from the contact lenses were recovered from the lens case and lens care solutions of patient B. In both the patients the condition resolved on discontinuation of lens wear. Patient compliance as a requirement for successful contact lens wear is highlighted with the illustration of these cases.