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Sample records for human eye lens

  1. Gamma crystallins of the human eye lens.

    Science.gov (United States)

    Vendra, Venkata Pulla Rao; Khan, Ismail; Chandani, Sushil; Muniyandi, Anbukkarasi; Balasubramanian, Dorairajan

    2016-01-01

    Protein crystallins co me in three types (α, β and γ) and are found predominantly in the eye, and particularly in the lens, where they are packed into a compact, plastic, elastic, and transparent globule of proper refractive power range that aids in focusing incoming light on to the retina. Of these, the γ-crystallins are found largely in the nuclear region of the lens at very high concentrations (>400 mg/ml). The connection between their structure and inter-molecular interactions and lens transparency is an issue of particular interest. We review the origin and phylogeny of the gamma crystallins, their special structure involving the use of Greek key supersecondary structural motif, and how they aid in offering the appropriate refractive index gradient, intermolecular short range attractive interactions (aiding in packing them into a transparent ball), the role that several of the constituent amino acid residues play in this process, the thermodynamic and kinetic stability and how even single point mutations can upset this delicate balance and lead to intermolecular aggregation, forming light-scattering particles which compromise transparency. We cite several examples of this, and illustrate this by cloning, expressing, isolating and comparing the properties of the mutant protein S39C of human γS-crystallin (associated with congenital cataract-microcornea), with those of the wild type molecule. In addition, we note that human γ-crystallins are also present in other parts of the eye (e.g., retina), where their functions are yet to be understood. There are several 'crucial' residues in and around the Greek key motifs which are essential to maintain the compact architecture of the crystallin molecules. We find that a mutation that replaces even one of these residues can lead to reduction in solubility, formation of light-scattering particles and loss of transparency in the molecular assembly. Such a molecular understanding of the process helps us construct the

  2. Composite modified Luneburg model of human eye lens.

    Science.gov (United States)

    Gómez-Correa, J E; Balderas-Mata, S E; Pierscionek, B K; Chávez-Cerda, S

    2015-09-01

    A new lens model based on the gradient-index Luneburg lens and composed of two oblate half spheroids of different curvatures is presented. The spherically symmetric Luneburg lens is modified to create continuous isoindicial contours and to incorporate curvatures that are similar to those found in a human lens. The imaging capabilities of the model and the changes in the gradient index profile are tested for five object distances, for a fixed geometry and for a fixed image distance. The central refractive index decreases with decreasing object distance. This indicates that in order to focus at the same image distance as is required in the eye, a decrease in refractive power is needed for rays from closer objects that meet the lens surface at steeper angles compared to rays from more distant objects. This ensures a highly focused image with no spherical aberration.

  3. Dating the time of birth: A radiocarbon calibration curve for human eye-lens crystallines

    DEFF Research Database (Denmark)

    Kjeldsen, Henrik; Heinemeier, Jan; Heegaard, Steffen

    2010-01-01

    Radiocarbon bomb-pulse dating has been used to measure the formation age of human eye-lens crystallines. Lens crystallines are special proteins in the eye-lens that consist of virtually inert tissue. The experimental data show that the radiocarbon ages to a large extent reflect the time of birth...

  4. Dating the time of birth: A radiocarbon calibration curve for human eye-lens crystallines

    Energy Technology Data Exchange (ETDEWEB)

    Kjeldsen, Henrik, E-mail: kjeldsen@phys.au.d [AMS 14C Dating Centre, Department of Physics and Astronomy, University of Aarhus, Aarhus (Denmark); Heinemeier, Jan [AMS 14C Dating Centre, Department of Physics and Astronomy, University of Aarhus, Aarhus (Denmark); Heegaard, Steffen [Eye Pathology Section, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen (Denmark); Jacobsen, Christina; Lynnerup, Niels [Department of Forensic Medicine, University of Copenhagen, Copenhagen (Denmark)

    2010-04-15

    Radiocarbon bomb-pulse dating has been used to measure the formation age of human eye-lens crystallines. Lens crystallines are special proteins in the eye-lens that consist of virtually inert tissue. The experimental data show that the radiocarbon ages to a large extent reflect the time of birth, in accordance with expectations. Moreover, it has been possible to develop an age model for the formation of the eye-lens crystallines. From this model a radiocarbon calibration curve for lens crystallines has been calculated. As a consequence, the time of birth of humans can be determined with an accuracy of a few years by radiocarbon dating.

  5. Dating the time of birth: A radiocarbon calibration curve for human eye-lens crystallines

    International Nuclear Information System (INIS)

    Kjeldsen, Henrik; Heinemeier, Jan; Heegaard, Steffen; Jacobsen, Christina; Lynnerup, Niels

    2010-01-01

    Radiocarbon bomb-pulse dating has been used to measure the formation age of human eye-lens crystallines. Lens crystallines are special proteins in the eye-lens that consist of virtually inert tissue. The experimental data show that the radiocarbon ages to a large extent reflect the time of birth, in accordance with expectations. Moreover, it has been possible to develop an age model for the formation of the eye-lens crystallines. From this model a radiocarbon calibration curve for lens crystallines has been calculated. As a consequence, the time of birth of humans can be determined with an accuracy of a few years by radiocarbon dating.

  6. Retinal images in the human eye with implanted intraocular lens

    Science.gov (United States)

    Zając, Marek; Siedlecki, Damian; Nowak, Jerzy

    2007-04-01

    A typical proceeding in cataract is based on the removal of opaque crystalline lens and inserting in its place the artificial intraocular lens (IOL). The quality of retinal image after such procedure depends, among others, on the parameters of the IOL, so the design of the implanted lens is of great importance. An appropriate choice of the IOL material, especially in relation to its biocompatibility, is often considered. However the parameter, which is often omitted during the IOL design is its chromatic aberration. In particular lack of its adequacy to the chromatic aberration of a crystalline lens may cause problems. In order to fit better chromatic aberration of the eye with implanted IOL to that of the healthy eye we propose a hybrid - refractive-diffractive IOL. It can be designed in such way that the total longitudinal chromatic aberration of an eye with implanted IOL equals the total longitudinal chromatic aberration of a healthy eye. In this study we compare the retinal image quality calculated numerically on the basis of the well known Liou-Brennan eye model with typical IOL implanted with that obtained if the IOL is done as hybrid (refractive-diffractive) design.

  7. Dose conversion coefficients for neutron exposure to the lens of the human eye

    International Nuclear Information System (INIS)

    Manger, Ryan P.; Bellamy, Michael B.; Eckerman, Keith F.

    2011-01-01

    Dose conversion coefficients for the lens of the human eye have been calculated for neutron exposure at energies from 1 x 10 -9 to 20 MeV and several standard orientations: anterior-to-posterior, rotational and right lateral. MCNPX version 2.6.0, a Monte Carlo-based particle transport package, was used to determine the energy deposited in the lens of the eye. The human eyeball model was updated by partitioning the lens into sensitive and insensitive volumes as the anterior portion (sensitive volume) of the lens being more radiosensitive and prone to cataract formation. The updated eye model was used with the adult UF-ORNL mathematical phantom in the MCNPX transport calculations.

  8. Dose conversion coefficients for neutron exposure to the lens of the human eye

    International Nuclear Information System (INIS)

    Manger, R. P.; Bellamy, M. B.; Eckerman, K. F.

    2012-01-01

    Dose conversion coefficients for the lens of the human eye have been calculated for neutron exposure at energies from 1 x 10 -9 to 20 MeV and several standard orientations: anterior-to-posterior, rotational and right lateral. MCNPX version 2.6.0, a Monte Carlo-based particle transport package, was used to determine the energy deposited in the lens of the eye. The human eyeball model was updated by partitioning the lens into sensitive and insensitive volumes as the anterior portion (sensitive volume) of the lens being more radiosensitive and prone to cataract formation. The updated eye model was used with the adult UF-ORNL mathematical phantom in the MCNPX transport calculations. (authors)

  9. A Simple Model of the Accommodating Lens of the Human Eye

    Science.gov (United States)

    Oommen, Vinay; Kanthakumar, Praghalathan

    2014-01-01

    The human eye is often discussed as optically equivalent to a photographic camera. The iris is compared with the shutter, the pupil to the aperture, and the retina to the film, and both have lens systems to focus rays of light. Although many similarities exist, a major difference between the two systems is the mechanism involved in focusing an…

  10. 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.

  11. 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.

  12. Radiocarbon Dating of the Human Eye Lens Crystallines Reveal Proteins without Carbon Turnover throughout Life

    Science.gov (United States)

    Lynnerup, Niels; Kjeldsen, Henrik; Heegaard, Steffen; Jacobsen, Christina; Heinemeier, Jan

    2008-01-01

    Background Lens crystallines are special proteins in the eye lens. Because the epithelial basement membrane (lens capsule) completely encloses the lens, desquamation of aging cells is impossible, and due to the complete absence of blood vessels or transport of metabolites in this area, there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its 14C content from the atmospheric carbon dioxide. The 14C content of the lens proteins thus reflects the atmospheric content of 14C when the lens crystallines were formed. Precise radiocarbon dating is made possible by comparing the 14C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric 14C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even on a yearly basis this allows very accurate dating. Methodology/Principal Findings Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close relationship may be further expressed as a mathematical model, which takes into account the timing of the crystalline formation. Conclusions/Significance Such a life-long permanence of human tissue has hitherto only been described for dental enamel. In confront to dental enamel it must be held in mind that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the 14C content of various tissues may be used to assess turnover rates and degree of substitution (for example for brain cell DNA). Potential targets may be nervous tissues in terms of senile or pre-senile degradation, as well as other highly

  13. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life.

    Directory of Open Access Journals (Sweden)

    Niels Lynnerup

    Full Text Available BACKGROUND: Lens crystallines are special proteins in the eye lens. Because the epithelial basement membrane (lens capsule completely encloses the lens, desquamation of aging cells is impossible, and due to the complete absence of blood vessels or transport of metabolites in this area, there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its (14C content from the atmospheric carbon dioxide. The (14C content of the lens proteins thus reflects the atmospheric content of (14C when the lens crystallines were formed. Precise radiocarbon dating is made possible by comparing the (14C content of the lens crystallines to the so-called bomb pulse, i.e. a plot of the atmospheric (14C content since the Second World War, when there was a significant increase due to nuclear-bomb testing. Since the change in concentration is significant even on a yearly basis this allows very accurate dating. METHODOLOGY/PRINCIPAL FINDINGS: Our results allow us to conclude that the crystalline formation in the lens nucleus almost entirely takes place around the time of birth, with a very small, and decreasing, continuous formation throughout life. The close relationship may be further expressed as a mathematical model, which takes into account the timing of the crystalline formation. CONCLUSIONS/SIGNIFICANCE: Such a life-long permanence of human tissue has hitherto only been described for dental enamel. In confront to dental enamel it must be held in mind that the eye lens is a soft structure, subjected to almost continuous deformation, due to lens accommodation, yet its most important constituent, the lens crystalline, is never subject to turnover or remodelling once formed. The determination of the (14C content of various tissues may be used to assess turnover rates and degree of substitution (for example for brain cell DNA. Potential targets may be nervous tissues in terms of senile or pre

  14. Femtosecond laser-induced cavitations in the lens of the human eye

    DEFF Research Database (Denmark)

    Kessel, Line; Nymand, Jose; Harbst, Michael

    2007-01-01

    attempted to define the cavitation threshold in the human lens in vitro using multiphoton effects base d on radiation from a femtosecond 800 nm Ti:Sapphire laser. Cavitations were observed from pulse energy densities exceeding 16 mJ/cm2, but only after several minutes of exposure and not as a result...... laser effects in the len s that have a potential for therapeutic application and treatment of eye dis ease though further studies are needed to shed light on the nature of the formation of delayed cavitations....

  15. Lens artifacts in human fetal eyes - the challenge of interpreting the histomorphology of human fetal lenses.

    Science.gov (United States)

    Herwig, Martina C; Müller, Annette M; Klarmann-Schulz, Ute; Holz, Frank G; Loeffler, Karin U

    2014-01-01

    Evaluation of the lens, including cataractous changes, is often of paramount importance in the classification of fetal syndromes or forensic questions. On histology, the crystalline lens is - especially in fetal and infant eyes - an organ susceptible to numerous artifacts. Thus, the aim of our study was to study various factors (including fixatives) that might have an impact on lens histomorphology. Twenty eyes from ten fetuses (formalin fixation: n = 10, glutaraldehyde fixation: n = 10), matched for gestational age and abortion (spontaneous vs. induced), were investigated macroscopically and by light microscopy. Sections were stained with routine hematoxylin & eosin (H&E), and periodic acid schiff (PAS). The age of the fetal eyes ranged from 15 to 36 weeks of gestation. Lens artifacts were analyzed and compared to fetal and adult lenses with definitive cataractous changes. In addition, 34 eyes from 27 fetuses with trisomy 21 were investigated for lens changes. All lenses showed artifacts of varying extent, in particular globules, vacuoles, clefts, anterior/posterior capsular separation, subcapsular proteinaceous material, fragmentation of the lens capsule/epithelium, and a posterior umbilication. Glutaraldehyde-fixed lenses displayed less artifacts compared to those fixed in formalin. Slight differences in the appearance of artifacts were found dependent on the fixative (formaldehyde vs glutaraldehyde) and the kind of abortion (iatrogenous vs spontaneous). The gestational age did not have a significant influence on the type and extent of lens artifacts. The lenses from fetuses with trisomy 21 displayed similar lens artifacts with no specific findings. Alterations in fetal lens morphology are extremely frequent and variable. These artifacts have to be carefully taken into account when interpreting post-mortem findings. Thus, the postmortem diagnosis of a fetal cataract should be made with great caution, and should include, in adherence to our proposed

  16. Goat′s eye integrated with a human cataractous lens: A training model for phacoemulsification

    Directory of Open Access Journals (Sweden)

    Sabyasachi Sengupta

    2015-01-01

    Full Text Available A relatively simple and inexpensive technique to train surgeons in phacoemulsification using a goat′s eye integrated with a human cataractous nucleus is described. The goat′s eye is placed on a bed of cotton within the lumen of a cylindrical container. This is then mounted on a rectangular thermocol so that the limbus is presented at the surgical field. After making a clear corneal entry with a keratome, the trainer makes a 5-5.5 mm continuous curvilinear capsulorhexis in the anterior lens capsule, creates a crater of adequate depth in the cortex and inserts the human nucleus within this crater in the goat′s capsular bag. The surgical wound is sutured, and the goat′s eye is ready for training. Creating the capsulorhexis with precision and making the crater of adequate depth to snugly accommodate the human nucleus are the most important steps to prevent excessive wobbling of the nucleus while training.

  17. Goat's eye integrated with a human cataractous lens: A training model for phacoemulsification.

    Science.gov (United States)

    Sengupta, Sabyasachi; Dhanapal, Praveen; Nath, Manas; Haripriya, Aravind; Venkatesh, Rengaraj

    2015-03-01

    A relatively simple and inexpensive technique to train surgeons in phacoemulsification using a goat's eye integrated with a human cataractous nucleus is described. The goat's eye is placed on a bed of cotton within the lumen of a cylindrical container. This is then mounted on a rectangular thermocol so that the limbus is presented at the surgical field. After making a clear corneal entry with a keratome, the trainer makes a 5-5.5 mm continuous curvilinear capsulorhexis in the anterior lens capsule, creates a crater of adequate depth in the cortex and inserts the human nucleus within this crater in the goat's capsular bag. The surgical wound is sutured, and the goat's eye is ready for training. Creating the capsulorhexis with precision and making the crater of adequate depth to snugly accommodate the human nucleus are the most important steps to prevent excessive wobbling of the nucleus while training.

  18. Ultrastructural effects of silicone oil on the clear crystalline lens of the human eye.

    Science.gov (United States)

    Soliman, Wael; Sharaf, Mohamed; Abdelazeem, Khaled; El-Gamal, Dalia; Nafady, Allam

    2018-03-01

    To evaluate light and electron microscopic changes of the anterior capsule and its epithelium after clear lens extraction of vitrectomized myopic eyes with silicone oil tamponade. This prospective, controlled, non-randomized, interventional study included 20 anterior lens capsular specimens that were excised during combined clear lens extraction and silicone oil removal from previously vitrectomized highly myopic patients with silicone oil tamponade for previous retinal detachment surgeries. The specimens were examined via light microscopy and electron microscopy and compared with 20 anterior capsule specimens removed during clear lens extraction of non-vitrectomized highly myopic eyes. Light microscopic examination of clear lens anterior capsule specimens of vitrectomized myopic eyes filled with silicone oil showed relatively more flat cells with irregular outline of lens' epithelial cells with wide intercellular spaces, deeply stained nuclei, and multiple intracytoplasmic vacuoles. Scanning electron microscopy revealed collagenous surfaces filled with multiple pits, depressions, and abnormal deposits. Transmission electron microscopy revealed lens epithelial cells with apoptotic changes, many cytoplasmic vacuoles, and filopodia-like protrusions between lens epithelial cells and the capsule. Epithelial proliferation and multilayering were also observed. silicone oil may play a role in the development of apoptotic and histopathological changes in clear lens epithelial cells. Clarity of the lens at the time of silicone oil removal does not indicate an absence of cataractous changes. We found justification of combined clear lens extraction and silicone oil removal or combined phacovitrectomy when silicone oil injection is planned, but further long-term studies with larger patient groups are required.

  19. Lipid-protein interactions in plasma membranes of fiber cells isolated from the human eye lens.

    Science.gov (United States)

    Raguz, Marija; Mainali, Laxman; O'Brien, William J; Subczynski, Witold K

    2014-03-01

    The protein content in human lens membranes is extremely high, increases with age, and is higher in the nucleus as compared with the cortex, which should strongly affect the organization and properties of the lipid bilayer portion of intact membranes. To assess these effects, the intact cortical and nuclear fiber cell plasma membranes isolated from human lenses from 41- to 60-year-old donors were studied using electron paramagnetic resonance spin-labeling methods. Results were compared with those obtained for lens lipid membranes prepared from total lipid extracts from human eyes of the same age group [Mainali, L., Raguz, M., O'Brien, W. J., and Subczynski, W. K. (2013) Biochim. Biophys. Acta]. Differences were considered to be mainly due to the effect of membrane proteins. The lipid-bilayer portions of intact membranes were significantly less fluid than lipid bilayers of lens lipid membranes, prepared without proteins. The intact membranes were found to contain three distinct lipid environments termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain. However, the cholesterol bilayer domain, which was detected in cortical and nuclear lens lipid membranes, was not detected in intact membranes. The relative amounts of bulk and trapped lipids were evaluated. The amount of lipids in domains uniquely formed due to the presence of membrane proteins was greater in nuclear membranes than in cortical membranes. Thus, it is evident that the rigidity of nuclear membranes is greater than that of cortical membranes. Also the permeability coefficients for oxygen measured in domains of nuclear membranes were significantly lower than appropriate coefficients measured in cortical membranes. Relationships between the organization of lipids into lipid domains in fiber cells plasma membranes and the organization of membrane proteins are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Radiocarbon dating of the human eye lens crystallines reveal proteins without carbon turnover throughout life

    DEFF Research Database (Denmark)

    Lynnerup, Niels; Kjeldsen, Henrik; Heegaard, Steffen

    2008-01-01

    , there is no subsequent remodelling of these fibers, nor removal of degraded lens fibers. Human tissue ultimately derives its (14)C content from the atmospheric carbon dioxide. The (14)C content of the lens proteins thus reflects the atmospheric content of (14)C when the lens crystallines were formed. Precise radiocarbon...

  1. 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 ...

  2. Three-dimensional ray tracing in spherical and elliptical generalized Luneburg lenses for application in the human eye lens.

    Science.gov (United States)

    Gómez-Correa, J E; Coello, V; Garza-Rivera, A; Puente, N P; Chávez-Cerda, S

    2016-03-10

    Ray tracing in spherical Luneburg lenses has always been represented in 2D. All propagation planes in a 3D spherical Luneburg lens generate the same ray tracing, due to its radial symmetry. A geometry without radial symmetry generates a different ray tracing. For this reason, a new ray tracing method in 3D through spherical and elliptical Luneburg lenses using 2D methods is proposed. The physics of the propagation is shown here, which allows us to make a ray tracing associated with a vortex beam. A 3D ray tracing in a composite modified Luneburg lens that represents the human eye lens is also presented.

  3. Dose conversion coefficients for electron exposure of the human eye lens

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G; Zankl, M

    2009-01-01

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. Two questions arise from this situation: first, which dose quantity is related to the risk of developing a cataract, and second, which personal dose equivalent quantity is appropriate for monitoring this dose quantity. While the dose equivalent quantity H p (0.07) has often been seen as being sufficiently accurate for monitoring the dose to the lens of the eye, this would be questionable in the case when the dose limits were reduced and, thus, it may be necessary to generally use the dose equivalent quantity H p (3) for this purpose. The basis for a decision, however, must be the knowledge of accurate conversion coefficients from fluence to equivalent dose to the lens. This is especially important for low-penetrating radiation, for example, electrons. Formerly published values of conversion coefficients are based on quite simple models of the eye. In this paper, quite a sophisticated model of the eye including the inner structure of the lens was used for the calculations and precise conversion coefficients for electrons with energies between 0.2 MeV and 12 MeV, and for angles of radiation incidence between 0 deg. and 45 deg. are presented. Compared to the values adopted in 1996 by the International Commission on Radiological Protection (ICRP), the new values are up to 1000 times smaller for electron energies below 1 MeV, nearly equal at 1 MeV and above 4 MeV, and by a factor of 1.5 larger at about 1.5 MeV electron energy.

  4. Lens oscillations in the human eye. Implications for post-saccadic suppression of vision.

    Directory of Open Access Journals (Sweden)

    Juan Tabernero

    Full Text Available The eye changes gaze continuously from one visual stimulus to another. Using a high speed camera to record eye and lens movements we demonstrate how the crystalline lens sustains an inertial oscillatory decay movement immediately after every change of gaze. This behavior fit precisely with the movement of a classical damped harmonic oscillator. The time course of the oscillations range from 50 to 60 msec with an oscillation frequency of around 20 Hz. That has dramatic implications on the image quality at the retina on the very short times (∼50 msec that follow the movement. However, it is well known that our vision is nearly suppressed on those periods (post-saccadic suppression. Both phenomenon follow similar time courses and therefore might be synchronized to avoid the visual impairment.

  5. 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.)

  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. Relationship of cumulative low-level dose of ionizing radiation on human eye lens and occurrence of cataract

    International Nuclear Information System (INIS)

    Deolalikar, Raghavendra

    2015-01-01

    International Commission on Radiological Protection (ICRP), issued a statement on Tissue Reaction, lowering the equivalent dose limit for eye lens for occupational exposure to 20 mSv per year. With a view to determine presence of any relationship between the cumulative low-level occupational radiation dose to the eye lens and occurrence of cataract, departmental records of the annual medical examination of employees of Narora Atomic Power Plant were examined along with the NAPS eye camps and surgical records of the employees. Analysis of the data showed no demonstrable definite relationship between the two. The analysis of the data and the observations are discussed in this paper. (author)

  8. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations.

    Science.gov (United States)

    Nogueira, P; Zankl, M; Schlattl, H; Vaz, P

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  9. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    International Nuclear Information System (INIS)

    Nogueira, P; Vaz, P; Zankl, M; Schlattl, H

    2011-01-01

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  10. 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)

  11. 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.

  12. 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)

  13. 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)

  14. Scleral lens use in dry eye syndrome.

    Science.gov (United States)

    Bavinger, J Clay; DeLoss, Karen; Mian, Shahzad I

    2015-07-01

    Dry eye syndrome can be difficult to manage in severe or refractory cases. In patients in whom traditional treatments have limited efficacy, alternative treatments may be considered for dry eye syndrome, including scleral lenses. The present review summarizes the evidence regarding scleral lens use in dry eye syndrome. Scleral lenses have become a viable option for severe dry eye syndrome, and have been shown to be efficacious and well tolerated, with most reports citing improved visual acuity and relief of symptoms. Currently, there are 18 manufacturers of scleral lenses, although published reports on scleral lenses primarily focus on the BostonSight PROSE and the Jupiter Lens. Scleral lenses are efficacious and well tolerated for use in severe dry eye syndrome. Further research is needed to compare different sizes and types of lenses, and to standardize outcome measures.

  15. The Correlation between Daily Lens Wear Duration and Dry Eye Syndrome.

    Science.gov (United States)

    Lubis, Rodiah Rahmawaty; Gultom, Monica Tumiar Hanna

    2018-05-20

    To analyze the correlation between the daily lens wear duration and dry eye syndrome. This study was an analytic cross sectional study using consecutive sampling conducted among the students in Economy and Bussiness Faculty and Faculty of Humanities in University of Sumatera Utara aged between 17 to 23 that wore contact lens continously for at least a year and 5 days a week. The symptoms were assessed using Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8) and interview about their contact lens comfort; eye drops usage, contact lens washing habit, daily circumstances, places to buy contact lens and personal experince in wearing contact lens. The questionnaire was completed by 53 students. All of them were female and wore softlens wearers. The mean duration of daily wear was 8.19 ± 2.20 hours. The most common symptom experienced was dry eye and the least symptom experienced was removing lens. The most frequent symptom experienced was closing eyes and the least frequent symptom experienced was removing lenses. This study used Exact Test as analysis statistic method. The result was p > 0.05 which means there is no correlation between daily lens wear duration and dry eye syndrome. This study showed that dry eye syndrome was not correlated with daily lens wear duration, but affected by many factors such as contact lens, lens care solution, eye drops usage and environment.

  16. Radiation dose to the eye lens

    DEFF Research Database (Denmark)

    Baun, Christina; Falch Braas, Kirsten; D. Nielsen, Kamilla

    2015-01-01

    Radiation Dose to the Eye Lens: Does Positioning Really Matter? C. Baun1, K. Falch1, K.D. Nielsen2, S. Shanmuganathan1, O. Gerke1, P.F. Høilund-Carlsen1 1Department of Nuclear Medicine, Odense University Hospital, Odense C, Denmark. 2University College Lillebaelt, Odense, Denmark. Aim: The scan...... field in oncology patients undergoing eyes-to-thighs PET/CT must always include the base of the scull according to department guidelines. The eye lens is sensitive to radiation exposure and if possible it should be avoided to scan the eye. If the patient’s head is kipped backwards during the scan one...... might avoid including the eye in the CT scan without losing sufficient visualization of the scull base. The aim of this study was to evaluate the possibility of decreasing the radiation dose to the eye lens, simply by changing the head position, when doing the PET/CT scan from the base of the scull...

  17. Intraocular lens calculations in atypical eyes

    Directory of Open Access Journals (Sweden)

    Aazim A Siddiqui

    2017-01-01

    Full Text Available Cataract surgery is the most performed surgical procedure in the field of ophthalmology. The process of intraocular lens (IOL calculations is a critical step to achieving successful outcomes. Many IOL formulae exist to guide surgeons through the difficult process of picking the most appropriate lens to achieve a certain target refraction. However, these formulae reach within 0.50 diopters of the target refraction only 75% of the time, leaving 25% of the eyes with a significant refractive surprise. A literature review was performed to investigate all the relevant published material on the history, progress, and recent advancements of IOL calculations. Based on this review, the appropriate history, evolution, progress, limitations, and recent advancements are analyzed and explained. Although the modern IOL formulae and biometric devices perform well for average eyes, they are suboptimal for eyes with atypical biometric parameters and also those that are postrefractive and keratoconic. There has not been a single, perfect formula that can resolve the complexities of this process. Various methods of formula optimization and newer generation of IOL formulae and devices may hold the key to improving outcomes in both typical and atypical eyes. These solutions minimize refractive error by introducing new input parameters and complex mathematical techniques to better estimate postoperative lens position.

  18. 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.

  19. 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.

  20. Status of eye lens radiation dose monitoring in European hospitals

    International Nuclear Information System (INIS)

    Carinou, Eleftheria; Ginjaume, Merce; O’Connor, Una; Kopec, Renata; Sans Merce, Marta

    2014-01-01

    A questionnaire was developed by the members of WG12 of EURADOS in order to establish an overview of the current status of eye lens radiation dose monitoring in hospitals. The questionnaire was sent to medical physicists and radiation protection officers in hospitals across Europe. Specific topics were addressed in the questionnaire such as: knowledge of the proposed eye lens dose limit; monitoring and dosimetry issues; training and radiation protection measures. The results of the survey highlighted that the new eye lens dose limit can be exceeded in interventional radiology procedures and that eye lens protection is crucial. Personnel should be properly trained in how to use protective equipment in order to keep eye lens doses as low as reasonably achievable. Finally, the results also highlighted the need to improve the design of eye dosemeters in order to ensure satisfactory use by workers. (paper)

  1. A Model of the Human Eye

    Science.gov (United States)

    Colicchia, G.; Wiesner, H.; Waltner, C.; Zollman, D.

    2008-01-01

    We describe a model of the human eye that incorporates a variable converging lens. The model can be easily constructed by students with low-cost materials. It shows in a comprehensible way the functionality of the eye's optical system. Images of near and far objects can be focused. Also, the defects of near and farsighted eyes can be demonstrated.

  2. Treatment of contact lens related dry eye with antibacterial honey.

    Science.gov (United States)

    Wong, Daniel; Albietz, Julie M; Tran, Huan; Du Toit, Cimonette; Li, Anita Hui; Yun, Tina; Han, Jee; Schmid, Katrina L

    2017-12-01

    Contact lens induced dry eye affects approximately 50% of contact lens wearers. The aim was to assess the effects of Manuka (Leptospermum sp.) honey eye drops (Optimel, Melcare, Australia) on dry eye in contact lens wearers. The safety of the honey eye drops in contact lens wear and contact lens wearers' compliance were also evaluated. Prospective, randomised, cross over study, examiner masked, pilot treatment trial. Twenty-four participants aged 20 to 55 years with contact lens related dry eye were recruited and randomised to two treatment groups; 20 completed the study. One group used Optimel eye drops twice a day for two weeks followed by conventional lubricant (Systane Ultra, Alcon) therapy for two weeks; the other group completed the treatments in the reverse order. Before and after each treatment dry eye symptomology, ocular surface inflammation, and tear quantity and quality were assessed. Participants completed a daily log detailing their usage of treatments and any issues. Dry eye symptoms improved significantly after Optimel treatment. Patients with more severe symptoms at baseline showed a greater improvement in symptoms. No significant differences were observed in the objective signs of dry eye; presumably because of the short treatment duration. Seventy-five% of contact lens wearers reported good adherence to Optimel treatment and 95% reported no issues using this product. Optimel Eye Drops reduce the symptoms of dry eye in contact lens wearers and are safe to use. A longer treatment period to assess the effect on clinical signs of dry eye is required. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  3. 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.

  4. Cholesterol Bilayer Domains in the Eye Lens Health: A Review.

    Science.gov (United States)

    Widomska, Justyna; Subczynski, Witold K; Mainali, Laxman; Raguz, Marija

    2017-12-01

    The most unique biochemical characteristic of the eye lens fiber cell plasma membrane is its extremely high cholesterol content, the need for which is still unclear. It is evident, however, that the disturbance of Chol homeostasis may result in damages associated with cataracts. Electron paramagnetic resonance methods allow discrimination of two types of lipid domains in model membranes overloaded with Chol, namely, phospholipid-cholesterol domains and pure Chol bilayer domains. These domains are also detected in human lens lipid membranes prepared from the total lipids extracted from lens cortices and nuclei of donors from different age groups. Independent of the age-related changes in phospholipid composition, the physical properties of phospholipid-Chol domains remain the same for all age groups and are practically identical for cortical and nuclear membranes. The presence of Chol bilayer domains in these membranes provides a buffering capacity for cholesterol concentration in the surrounding phospholipid-Chol domains, keeping it at a constant saturating level and thus keeping the physical properties of the membrane consistent with and independent of changes in phospholipid composition. It seems that the presence of Chol bilayer domains plays an integral role in the regulation of cholesterol-dependent processes in fiber cell plasm membranes and in the maintenance of fiber cell membrane homeostasis.

  5. On the operational quantity Hp(3) for eye lens dosimetry

    International Nuclear Information System (INIS)

    Behrens, R

    2012-01-01

    In the past the operational quantity H p (3) has been defined for calibration purposes in a slab phantom. Recently, an additional phantom in the form of a cylinder was suggested for eye lens dosimetry as a cylinder much better approximates the shape of a head than a slab. Therefore, this work investigates whether the quantity H p (3), when defined in the respective calibration phantom, adequately estimates the eye lens dose (or is at least conservative) depending on the phantom: it turns out that in most cases both calibration phantoms are similarly well suited. Finally, the definition of the eye lens dose is discussed together with possible consequences on the definition of H p (3): the consideration of only the radiation sensitive volume of the lens causes H p (3) not to be conservative in beta radiation fields. (paper)

  6. Monitoring the eye lens: which dose quantity is adequate?

    International Nuclear Information System (INIS)

    Behrens, R; Dietze, G

    2010-01-01

    Recent epidemiological studies suggest a rather low dose threshold (below 0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimized and current dose limits for the eye lens may be reduced in the future. The question of which personal dose equivalent quantity is appropriate for monitoring the dose to the eye lens arises from this situation. While in many countries dosemeters calibrated in terms of the dose equivalent quantity H p (0.07) have been seen as being adequate for monitoring the dose to the eye lens, this might be questionable in the case of reduced dose limits and, thus, it may become necessary to use the dose equivalent quantity H p (3) for this purpose. To discuss this question, the dose conversion coefficients for the equivalent dose of the eye lens (in the following eye lens dose) were determined for realistic photon and beta radiation fields and compared with the values of the corresponding conversion coefficients for the different operational quantities. The values obtained lead to the following conclusions: in radiation fields where most of the dose comes from photons, especially x-rays, it is appropriate to use dosemeters calibrated in terms of H p (0.07) on a slab phantom, while in other radiation fields (dominated by beta radiation or unknown contributions of photon and beta radiation) dosemeters calibrated in terms of H p (3) on a slab phantom should be used. As an alternative, dosemeters calibrated in terms of H p (0.07) on a slab phantom could also be used; however, in radiation fields containing beta radiation with the end point energy near 1 MeV, an overestimation of the eye lens dose by up to a factor of 550 is possible.

  7. 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)

  8. Shielding effect of lead glasses on radiologists' eye lens exposure in interventional procedures

    International Nuclear Information System (INIS)

    Hu, Panpan; Kong, Yan; Chen, Bo; Liu, Qianqian; Zhuo, Weihai; Liu, Haikuan

    2017-01-01

    To study the shielding effect of radiologists' eye lens with lead glasses of different equivalent thicknesses and sizes in interventional radiology procedures. Using the human voxel phantom with a more accurate model of the eye and MCNPX software, eye lens doses of the radiologists who wearing different kinds of lead glasses were simulated, different beam projections were taken into consideration during the simulation. Measurements were also performed with the physical model to verify simulation results. Simulation results showed that the eye lens doses were reduced by a factor from 3 to 9 when wearing a 20 cm"2-sized lead glasses with the equivalent thickness ranging from 0.1 to 1.0 mm Pb. The increase of dose reduction factor (DRF) was not significant whenever increase the lead equivalent of glasses of which larger than 0.35 mm. Furthermore, the DRF was proportional to the size of glass lens from 6 to 30 cm"2 with the same lead equivalent. The simulation results were in well agreements with the measured ones. For more reasonable and effective protection of the eye lens of interventional radiologists, a pair of glasses with a lead equivalent of 0.5 mm Pb and large-sized (at least 27 cm"2 per glass) lens are recommended (authors)

  9. Shielding Effect of Lead Glasses on Radiologists' Eye Lens Exposure in Interventional Procedures.

    Science.gov (United States)

    Hu, Panpan; Kong, Yan; Chen, Bo; Liu, Qianqian; Zhuo, Weihai; Liu, Haikuan

    2017-04-20

    To study the shielding effect of radiologists' eye lens with lead glasses of different equivalent thicknesses and sizes in interventional radiology procedures. Using the human voxel phantom with a more accurate model of the eye and MCNPX software, eye lens doses of the radiologists who wearing different kinds of lead glasses were simulated, different beam projections were taken into consideration during the simulation. Measurements were also performed with the physical model to verify simulation results. Simulation results showed that the eye lens doses were reduced by a factor from 3 to 9 when wearing a 20 cm2-sized lead glasses with the equivalent thickness ranging from 0.1 to 1.0 mm Pb. The increase of dose reduction factor (DRF) was not significant whenever increase the lead equivalent of glasses of which larger than 0.35 mm. Furthermore, the DRF was proportional to the size of glass lens from 6 to 30 cm2 with the same lead equivalent. The simulation results were in well agreements with the measured ones. For more reasonable and effective protection of the eye lens of interventional radiologists, a pair of glasses with a lead equivalent of 0.5 mm Pb and large-sized (at least 27 cm2 per glass) lens are recommended. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Equivalent refractive index of the human lens upon accommodative response

    NARCIS (Netherlands)

    Hermans, E.A.; Dubbelman, M.; van der Heijde, R.G.L.; Heethaar, R.M.

    2008-01-01

    PURPOSE.: To experimentally verify the suggestion of Gullstrand (1909), i.e., that the equivalent refractive index of the human lens increases with accommodation. METHODS.: The left eye of five subjects was focused on different accommodation stimuli, while the right eye was imaged with Scheimpflug

  11. Radiation dose to physicians’ eye lens during interventional radiology

    International Nuclear Information System (INIS)

    Bahruddin, N A; Hashim, S; Karim, M K A; Ang, W C; Salehhon, N; Sabarudin, A; Bakar, K A

    2016-01-01

    The demand of interventional radiology has increased, leading to significant risk of radiation where eye lens dose assessment becomes a major concern. In this study, we investigate physicians' eye lens doses during interventional procedures. Measurement were made using TLD-100 (LiF: Mg, Ti) dosimeters and was recorded in equivalent dose at a depth of 0.07 mm, Hp(0.07). Annual Hp(0.07) and annual effective dose were estimated using workload estimation for a year and Von Boetticher algorithm. Our results showed the mean Hp(0.07) dose of 0.33 mSv and 0.20 mSv for left and right eye lens respectively. The highest estimated annual eye lens dose was 29.33 mSv per year, recorded on left eye lens during fistulogram procedure. Five physicians had exceeded 20 mSv dose limit as recommended by international commission of radiological protection (ICRP). It is suggested that frequent training and education on occupational radiation exposure are necessary to increase knowledge and awareness of the physicians’ thus reducing dose during the interventional procedure. (paper)

  12. Contact lens wear and dry eyes: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Markoulli M

    2017-02-01

    Full Text Available Maria Markoulli, Sailesh Kolanu School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia Abstract: The number of contact lens wearers worldwide has remained relatively stable over the past decade, despite the investment that has gone into contact lens technology. This is largely because 10%–50% of wearers dropout of contact lens wear within 3 years of commencement; the most common reason cited being contact lens discomfort (CLD. Of the symptoms reported, sensation of dry eye is the most common. Given the outcome of reduced wearing time, increased chair time, and ultimate contact lens discontinuation, the challenge is to identify the warning signs of CLD early on. Clinically detectable changes such as conjunctival staining, conjunctival indentation, conjunctival epithelial flap formation, lid wiper epitheliopathy, Demodex blepharitis, and meibomian gland dysfunction have been linked to CLD, highlighting the need to perform regular aftercare visits to identify these changes. At a cellular level, conjunctival metaplasia and reduced goblet cell density have been linked to CLD, leading to a downstream effect on the tear film breakup time of contact lens wearers. These factors suggest a strong link between CLD and friction, raising the need to target this as a means of minimizing CLD. The purpose of this review is to identify the clinical signs that relate to CLD as a means of earlier detection and management in order to combat contact lens dropout. Keywords: contact lens discomfort, dry eye disease, lid wiper epitheliopathy, tear film biomarkers, meibomian gland dysfunction

  13. Determination of absorbed dose to the lens of eye from external sources

    International Nuclear Information System (INIS)

    Chen Lishu

    1993-01-01

    The methods of determining absorbed dose distributions in human eyeball by means of the experiments and available theories have been reported. A water phantom was built up. The distributions of beta dose were measured by an extrapolation ionization chamber at some depths corresponding to components of human eyeball such as cornea, sclera, anterior chamber and the lens of eye. The ratios among superficial absorbed dose (at 0.07 mm) and average absorbed doses at the depths 1,2,3 mm are obtained. They can be used for confining the deterministic effects of superficial tissues and organs such as the lens of eye for weakly penetrating radiations

  14. New device for the radiation protection of the eye lens

    International Nuclear Information System (INIS)

    Csobaly, S.; Zarand, P.

    1980-01-01

    Lenses of 50 mm diameter and 2 mm width were ground from lead glass, equivalent to 2 mm of lead. In the case of X-radiations of different intensity and different filtering the finished glasses are equivalent to 0.73-0.78 mm of lead and they decrease the radiation exposition of the eye lens 15-fold. (L.E.)

  15. Dose estimation for the eye lens dealing with radioactive wastes

    International Nuclear Information System (INIS)

    Krause, A.; Lorenz, B.; Wuertemberger, M.

    2013-01-01

    A significant reduction of the dose limit for the lens of the eye is currently discussed in international committees. The ICRP had recommended a reduction from 150 mSv to 20 mSv, the IAEA-BSS have already adopted this value and the Euratom-BSS propose this too. In the practice of radiation protection the compliance with the limit for the lens of the eye has played a minor role so far. This was in practice assured by the compliance with the limit for the effective dose. With a possible stipulation of a much lower value in the Radiation Protection Ordinance (StrlSchV), the question of compliance arises again. When handling radioactive waste where often gamma radiation is dominant it may happen that the (unshielded) eye region is much more exposed as the location of the (shielded) personal dosimeter. A theoretical study of typical GNS-workplaces in radioactive waste management has shown that up to a factor of 4 higher exposures may occur. A generic assessment under very conservative assumptions that was done first did not allow for the conclusion that the compliance of the new dose limit for the lens of the eye is given by complying with the limit for the effective dose. To get a more reliable basis the exposure situation will now be investigated by measurements that are carried out with specific TLDs provided by the MPA Dortmund. (orig.)

  16. 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.

  17. Estimation of eye lens doses received by pediatric interventional cardiologists.

    Science.gov (United States)

    Alejo, L; Koren, C; Ferrer, C; Corredoira, E; Serrada, A

    2015-09-01

    Maximum Hp(0.07) dose to the eye lens received in a year by the pediatric interventional cardiologists has been estimated. Optically stimulated luminescence dosimeters were placed on the eyes of an anthropomorphic phantom, whose position in the room simulates the most common irradiation conditions. Maximum workload was considered with data collected from procedures performed in the Hospital. None of the maximum values obtained exceed the dose limit of 20 mSv recommended by ICRP. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Eye-lens bismuth shielding in paediatric head CT: artefact evaluation and reduction

    International Nuclear Information System (INIS)

    Raissaki, Maria; Perisinakis, Kostas; Damilakis, John; Gourtsoyiannis, Nicholas

    2010-01-01

    CT scans of the brain, sinuses and petrous bones performed as the initial imaging test for a variety of indications have the potential to expose the eye-lens, considered among the most radiosensitive human tissues, to a radiation dose. There are several studies in adults discussing the reduction of orbital dose resulting from the use of commercially available bismuth-impregnated latex shields during CT examinations of the head. To evaluate bismuth shielding-induced artefacts and to provide suggestions for optimal eye-lens shielding in paediatric head CT. A bismuth shield was placed over the eyelids of 60 consecutive children undergoing head CT. Images were assessed for the presence and severity of artefacts with regard to eye-shield distance and shield wrinkling. An anthropomorphic paediatric phantom and thermoluminescence dosimeters (TLDs) were used to study the effect of eye lens-to-shield distance on shielding efficiency. Shields were tolerated by 56/60 children. Artefacts were absent in 45% of scans. Artefacts on orbits, not affecting and affecting orbit evaluation were noted in 39% and 14% of scans, respectively. Diagnostically insignificant artefacts on intracranial structures were noted in 1 case (2%) with shield misplacement. Mean eye-lens-to-shield distance was 8.8 mm in scans without artefacts, and 4.3 mm and 2.2 mm in scans with unimportant and diagnostically important artefacts, respectively. Artefacts occurred in 8 out of 9 cases with shield wrinkling. Dose reduction remained unchanged for different shield-to-eye distances. Bismuth shielding-related artefacts occurring in paediatric head CT are frequent, superficial and diagnostically insignificant when brain pathology is assessed. Shields should be placed 1 cm above the eyes when orbital pathology is addressed. Shield wrinkling should be avoided. (orig.)

  19. 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)

  20. TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionists

    Energy Technology Data Exchange (ETDEWEB)

    Rehani, M. [Massachusetts General Hospital (United States)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  1. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. [Seoul National University Hospital (Korea, Republic of)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  2. TU-E-201-01: Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionists

    International Nuclear Information System (INIS)

    Rehani, M.

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  3. TU-E-201-03: Eye Lens Dosimetry in Radiotherapy Using Contact Lens-Shaped Applicator

    International Nuclear Information System (INIS)

    Park, J.

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  4. Aquaporins 6-12 in the human eye

    DEFF Research Database (Denmark)

    Tran, Thuy Linh; Bek, Toke; Holm, Lars

    2012-01-01

    Purpose: Aquaporins (AQPs) are widely expressed and have diverse distribution patterns in the eye. AQPs 0-5 have been localized at the cellular level in human eyes. We investigated the presence of the more recently discovered AQPs 6-12 in the human eye. Methods: RT-PCR was performed on fresh tissue...... from two human eyes divided into the cornea, corneal limbus, ciliary body and iris, lens, choroid, optic nerve, retina and sclera. Each structure was examined to detect the mRNA of AQPs 6-12. Twenty-one human eyes were examined using immunohistochemical and immunofluorescence techniques to determine...... was detected in the corneal epithelium, corneal endothelium, trabecular meshwork endothelium, ciliary epithelia, lens epithelium, the inner and outer limiting membrane of the retina, the retinal pigment epithelium and the capillary endothelium of all parts of the eye. AQP9 immunolabelling was detected...

  5. Design of a new two element OSLD Badge for eye lens monitoring

    International Nuclear Information System (INIS)

    Kulkarni, M.S.; Munish Kumar; Ratna, P.; Babu, D.A.R.; Muthe, K.P.; Biju, K.; Sunil, C.; Sharma, D.N.

    2014-01-01

    Normally the dose to the vicinity of the eye is received by the occupational radiation workers who handle radioisotopes or doctors who perform interventional radiographic procedures. The Eye dosimeters provide an estimate of the radiation dose to the lens of the eye. In the recent ICRP-2011 recommendations, the equivalent dose limit for the lens of the eye has been reduced from 150 mSv in a year to 20 mSv in a year for all the occupational workers. To ensure that the dose limit for the eye lens does not exceed the prescribed dose limits, various eye lens dosimeters have been designed and are being used internationally. All these eye dosimeters consist of one natural LiF based thermoluminescence dosimeter (TLD) element sealed in a plastic holder. The design of the eye dosimeter and place of wear (near the eye) plays an important role in correct estimation of the dose to the lens of the eye. It is generally seen that the eye dosimeter when worn with the head strap on the forehead near the eye, the dose the element receives can be easily correlated to the eye dose. This paper presents the design of a new Eye lens dosimeter based on optically stimulated luminescence (OSL) detectors for its possible use by the occupational workers covering the medical, industrial and nuclear facilities for assessing the Hp(3)

  6. Temporal properties of the lens eyes of the box jellyfish Tripedalia cystophora

    DEFF Research Database (Denmark)

    O'Connor, Megan; Nilsson, Dan-E; Garm, Anders Lydik

    2010-01-01

    Box jellyWsh (Cubomedusae) are visually orientating animals which posses a total of 24 eyes of 4 morphological types; 2 pigment cup eyes (pit eye and slit eye) and 2 lens eyes [upper lens-eye (ule) and lower lens-eye (lle)]. In this study, we use electroretinograms (ERGs) to explore temporal...... properties of the two lens eyes. We Wnd that the ERG of both lens eyes are complex and using sinusoidal Xicker stimuli we Wnd that both lens eyes have slow temporal resolution. The average Xicker fusion frequency (FFF) was found to be approximately 10 Hz for the ule and 8 Hz for the lle. Di......Verences in the FFF and response patterns between the two lens eyes suggest that the ule and lle Wlter information diVerently in the temporal domain and thus are tuned to perform diVerent visual tasks. The data collected in this study support the idea that the visual system of box jellyWsh is a collection of special...

  7. Control development of radiation protection and safety on personnel eye lens of interventional radiology

    International Nuclear Information System (INIS)

    Titik Kartika; Ishak

    2013-01-01

    The review on radiation protection and safety to the lens of personnel especially in interventional radiology activities has been carried out. The use of radiation in interventional radiology installations provide significant exposure to the lens of the eye, especially personnel. The results of the latest various surveys and researches on the effects of low dose radiation to the eye lens indicates that the eye lens dose threshold is less than the preconceived values. Based on these facts, recently, ICRP and IAEA provides recommendations regarding the reduction of the value of the eye lens dose limit for personnel. BAPETEN have adopted the value of the eye lens dose limit in the development of new regulations on radiation protection and safety. However, the application of this provision has various challenges that BAPETEN provide 3 (three) years transitional period. These challenges include the problem of monitoring the eye lens dose, the eye lens protective equipment which is not adequate, the lack of understanding of personnel related to the risk of low radiation to the eye lens, as well as the proper procedures to mitigate those risks. BAPETEN as a regulatory agency is expected to provide solutions to the problems faced by the stake holders. Therefore, to answer the challenge, it is necessary to develop better monitoring of radiation protection and safety. (author)

  8. Occupational eye lens doses in interventional cardiology. A multicentric study

    International Nuclear Information System (INIS)

    Sánchez, R M; Vano, E; Fernández, J M; Pifarré, X; Ordiales, J M; Rovira, J J; Carrera, F; Goicolea, J; Fernández-Ortiz, A

    2016-01-01

    New European regulation regarding radiological protection of workers and more specifically the new occupational dose limit for the eye lens recently reduced to 20 mSv yr −1 may affect interventional cardiologists. This paper presents a set of measurements of occupational doses performed in five interventional cardiology centres and then compared with the new dose limit. The measurement of occupational doses was performed over the apron at chest level using electronic dosemeters recording H p (10). In one of the centres, scatter dose at goggles was also measured with optically stimulated luminescence dosemeters calibrated in terms of H p (0.07). An average H p (10) over the apron of 46 μSv/procedure was measured for cardiologists. Lower doses were noted in other professionals like second cardiologists, nurses or anaesthetists. Procedures for valvular and other structural heart diseases involved the highest occupational doses, averaging over 100 μSv/procedure. Important differences in occupational doses among centres may be indicative of different radiation protection habits. The new occupational dose limit for the eye lens is likely to be exceeded by those among the interventionalists who do not use protection tools (ceiling suspended screen and/or goggles) even with standard workloads. (paper)

  9. 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.

  10. An acoustic Maxwell’s fish-eye lens based on gradient-index metamaterials

    International Nuclear Information System (INIS)

    Yuan Bao-guo; Tian Ye; Cheng Ying; Liu Xiao-jun

    2016-01-01

    We have proposed a two-dimensional acoustic Maxwell’s fish-eye lens by using the gradient-index metamaterials with space-coiling units. By adjusting the structural parameters of the units, the refractive index can be gradually varied, which is key role to design the acoustic fish-eye lens. As predicted by ray trajectories on a virtual sphere, the proposed lens has the capability to focus the acoustic wave irradiated from a point source at the surface of the lens on the diametrically opposite side of the lens. The broadband and low loss performance is further demonstrated for the lens. The proposed acoustic fish-eye lens is expected to have the potential applications in directional acoustic coupler or coherent ultrasonic imaging. (paper)

  11. Nanoceria have no genotoxic effect on human lens epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Pierscionek, Barbara K; Yasseen, Akeel A [School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA (United Kingdom); Li, Yuebin; Schachar, Ronald A; Chen, Wei [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Colhoun, Liza M, E-mail: b.pierscionek@ulster.ac.uk, E-mail: weichen@uta.edu [Centre for Vision and Vascular Sciences, School of Medicine, Dentistry and Biomedical Sciences, Queen' s University Belfast, Grosvenor Road, Belfast, BT12 6BA (United Kingdom)

    2010-01-22

    There are no treatments for reversing or halting cataract, a disease of the structural proteins in the eye lens, that has associations with other age-related degenerative conditions such as Alzheimer's disease. The incidence of cataract and associated conditions is increasing as the average age of the population rises. Protein folding diseases are difficult to assess in vivo as proteins and their age-related changes are assessed after extraction. Nanotechnology can be used to investigate protein changes in the intact lens as well as for a potential means of drug delivery. Nanoparticles, such as cerium oxide (CeO{sub 2}) which have antioxidant properties, may even be used as a means of treating cataract directly. Prior to use in treatments, nanoparticle genotoxicity must be tested to assess the extent of any DNA or chromosomal damage. Sister chromatid exchanges were measured and DNA damage investigated using the alkaline COMET assay on cultured human lens epithelial cells, exposed to 5 and 10 {mu}g ml{sup -1} of CeO{sub 2} nanoparticles (nanoceria). Nanoceria at these dosages did not cause any DNA damage or significant increases in the number of sister chromatid exchanges. The absence of genotoxic effects on lens cells suggests that nanoceria, in the doses and exposures tested in this study, are not deleterious to the eye lens and have the potential for use in studying structural alterations, in developing non-surgical cataract treatments and in investigating other protein folding diseases.

  12. Monitoring the eye lens: how do the international organisations react?

    International Nuclear Information System (INIS)

    Behrens, R.

    2015-01-01

    The International Commission on Radiological Protection (ICRP) has recommended to lower the limit of the dose to the eye lens for occupationally exposed persons to a mean value of 20 mSv y -1 (averaged over 5 y, with a maximum of 50 mSv y -1 ); already in the autumn of 2011, both the European Commission and the International Atomic Energy Agency (IAEA) took over this reduction in their respective draft basic safety standards. Even prior to this (and since then, increasingly so), several international activities were started (among other things, the following ones): (1) the ICRP adopted a stylised model of the eye to calculate dose conversion coefficients for its report ICRP 116; (2) the European Commission has funded the ORAMED project dealing with radiation protection in medicine; (3) in its standard IEC 62387 on passive dosimetry systems, the International Electrotechnical Commission (IEC) has laid down requirements for Hp(3) eye dosemeters; (4) the International Organization for Standardization (ISO) and the IAEA provide a range of practical advice in the standard ISO 15382 (still a draft) and in a technical document IAEA TecDoc on both radiation protection and on dosimetry; (5) for most cases, the International Commission on Radiation Units and Measurements (ICRU) recommends both phantoms (the slab and the cylinder). In short: most national procedures can orientate themselves on international ones; some questions, however, remain open. (authors)

  13. 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.

  14. Studies on α-Al2O3: C based optically stimulated luminescence badge for eye lens monitoring applications

    International Nuclear Information System (INIS)

    Kumar, Munish; Kulkarni, M.S.; Ratna, P.; Gaikwad, N.; Tripathi, S.M.; Sharma, S.D.; Babu, D.A.R.; Bhatnagar, Amit; Muthe, K.P.; Sharma, D.N.

    2014-01-01

    The prototype two element eye-lens dosimeter badge based on indigenously developed α-Al 2 O 3 : C optically stimulated luminescence dosimeter was investigated comprehensively for its suitability for eye-lens monitoring applications. The badge is calibrated to measure the eye-lens dose in terms of H p (3). The minimum measurable dose using the eye-lens dosimeter badge is observed to be ∼ 35 μSv. This prototype eye-lens dosimeter badge was found to be suitable for measuring doses from X-rays, beta and gamma radiations to the eye-lens. The satisfactory performance of the prototype two element eye-lens dosimeter badge along with its attractive features such as multiple readout, less processing time, very good beta response uniquely position it for monitoring the eye-lens dose are presented. (author)

  15. 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)

  16. Addendum report of the JHPS expert committee on radiation protection of the lens of the eye (1). Eye lens dosimetry R and D, and radiation management and estimated eye-lens exposure for workers in Japanese nuclear power plants

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Katoh, Masahiro; Kurosawa, Tadahiro; Kawaura, Chiyo; Tsujimura, Norio; Hayashida, Toshiyuki; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2015-01-01

    The Expert Committee on Radiation Protection of the Lens of the Eye was established under the Japan Health Physics Society in April, 2013 (completed, March, 2015). The Committee looked at new/revised documents and standards related to the eye lens published by international organizations such as the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU). The Committee also examined recent and previous studies related to eye-lens radiation exposure and dosimetry in Japan. These findings were published in this journal as the Interim Report of the Committee. Since then, the Committee expanded its activity to give an overview the current progress of eye-lens dosimetry R and D at the National Institute of Advanced Industrial Science and Technology, along with research related to radiation management and estimated eye-lens exposure of Japanese nuclear-power-plant workers (including those at Fukushima Daiichi Nuclear Power Plant) for publishing an addendum Committee report. These additional findings are reported here. (author)

  17. Clinical study of foldable intraocular lens secondary implantation after lens-vitrectomy in residual capsular with traumatic eyes

    Directory of Open Access Journals (Sweden)

    Ru-Fa Meng

    2015-07-01

    Full Text Available AIM: To investigate the operation methods and clinical effects of foldable intraocular lens secondary implantation after lens-vitrectomy in residual capsular with traumatic eyes.METHODS: During January 2012 to January 2014, foldable intraocular lens was implanted on 47 cases following lens-vitrectomy in residual capsular with traumatic eyes 3~6mo. Follow-up period was 6~12mo, averaged(8.21±2.63mo. RESULTS:All of 47 eyes had successful operation at one time, and position deviation was not appeared. The naked vision of the last postoperative follow-up was(0.44±0.19. Compared with best corrected visual acuity(0.41±0.23, and There was no significant difference between visual acuity of preoperative and last follow-up period(t=0.879, P=0.342. No severe complication was found. CONCLUSION: Secondary implantation of foldable intraocular lens is a safe and reliable method for correcting ametropia after lens-vitrectomy in residual capsular with traumatic eyes.

  18. TU-E-201-02: Eye Lens Dosimetry From CT Perfusion Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, D. [Toshiba America Medical Systems (United States)

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  19. TU-E-201-00: Eye Lens Dosimetry for Patients and Staff

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  20. TU-E-201-02: Eye Lens Dosimetry From CT Perfusion Studies

    International Nuclear Information System (INIS)

    Zhang, D.

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  1. TU-E-201-00: Eye Lens Dosimetry for Patients and Staff

    International Nuclear Information System (INIS)

    2015-01-01

    Madan M. Rehani, Massachusetts General Hospital and Harvard Medical School, Boston Methods for Eye Lens Dosimetry and Studies On Lens Opacities with Interventionalists Radiation induced cataract is a major threat among staff working in interventional suites. Nearly 16 million interventional procedures are performed annually in USA. Recent studies by the principal investigator’s group, primarily among interventional cardiologists, on behalf of the International Atomic Energy Agency, show posterior subcapsular (PSC) changes in the eye lens in 38–53% of main operators and 21–45% of support staff. These changes have potential to lead to cataract in future years, as per information from A-Bomb survivors. The International Commission on Radiological Protection has reduced dose limit for staff by a factor of 7.5 (from 150 mSv/y to 20 mSv/y). With increasing emphasis on radiation induced cataracts and reduction in threshold dose for eye lens, there is a need to implement strategies for estimating eye lens dose. Unfortunately eye lens dosimetry is at infancy when it comes to routine application. Various approaches are being tried namely direct measurement using active or passive dosimeters kept close to eyes, retrospective estimations and lastly correlating patient dose in interventional procedures with staff eye dose. The talk will review all approaches available and ongoing active research in this area, as well as data from surveys done in Europe on status of eye dose monitoring in interventional radiology and nuclear medicine. The talk will provide update on how good is Hp(10) against Hp(3), estimations from CTDI values, Monte Carlo based simulations and current status of eye lens dosimetry in USA and Europe. The cataract risk among patients is in CT examinations of the head. Since radiation induced cataract predominantly occurs in posterior sub-capsular (PSC) region and is thus distinguishable from age or drug related cataracts and is also preventable, actions on

  2. The spectral sensitivity of the lens eyes of a box jellyfish, Tripedalia cystophora (Conant)

    DEFF Research Database (Denmark)

    Coates, Melissa M; Garm, Anders; Theobald, Jamie C

    2006-01-01

    Box jellyfish, or cubomedusae (class Cubozoa), are unique among the Cnidaria in possessing lens eyes similar in morphology to those of vertebrates and cephalopods. Although these eyes were described over 100 years ago, there has been no work done on their electrophysiological responses to light. ...... result from the presence of a single receptor type containing a single opsin. The peak sensitivity is to blue-green light. Visual pigment template fits indicate a vitamin A-1 based opsin with peak sensitivity near 500 nm for both eye types.......Box jellyfish, or cubomedusae (class Cubozoa), are unique among the Cnidaria in possessing lens eyes similar in morphology to those of vertebrates and cephalopods. Although these eyes were described over 100 years ago, there has been no work done on their electrophysiological responses to light. We...... used an electroretinogram (ERG) technique to measure spectral sensitivity of the lens eyes of the Caribbean species Tripedalia cystophora. The cubomedusae have two kinds of lens eyes, the lower and upper lens eyes. We found that both lens eye types have similar spectral sensitivities, which likely...

  3. Optical models of the human eye.

    Science.gov (United States)

    Atchison, David A; Thibos, Larry N

    2016-03-01

    Optical models of the human eye have been used in visual science for purposes such as providing a framework for explaining optical phenomena in vision, for predicting how refraction and aberrations are affected by change in ocular biometry and as computational tools for exploring the limitations imposed on vision by the optical system of the eye. We address the issue of what is understood by optical model eyes, discussing the 'encyclopaedia' and 'toy train' approaches to modelling. An extensive list of purposes of models is provided. We discuss many of the theoretical types of optical models (also schematic eyes) of varying anatomical accuracy, including single, three and four refracting surface variants. We cover the models with lens structure in the form of nested shells and gradient index. Many optical eye models give accurate predictions only for small angles and small fields of view. If aberrations and image quality are important to consider, such 'paraxial' model eyes must be replaced by 'finite model' eyes incorporating features such as aspheric surfaces, tilts and decentrations, wavelength-dependent media and curved retinas. Many optical model eyes are population averages and must become adaptable to account for age, gender, ethnicity, refractive error and accommodation. They can also be customised for the individual when extensive ocular biometry and optical performance data are available. We consider which optical model should be used for a particular purpose, adhering to the principle that the best model is the simplest fit for the task. We provide a glimpse into the future of optical models of the human eye. This review is interwoven with historical developments, highlighting the important people who have contributed so richly to our understanding of visual optics. © 2016 The Authors. Clinical and Experimental Optometry © 2016 Optometry Australia.

  4. Risk of eye lens radiation exposure for members of the public

    International Nuclear Information System (INIS)

    Chevallier, M.-A.; Rannou, A.; Villagrasa, C.; Clairand, I.

    2016-01-01

    In 2011, the International Commission on Radiological Protection (ICRP) reviewed its recommendation concerning the equivalent dose limit for the eye lens, lowering it to 20 mSv in a year, for occupational exposure in planned exposure situations. The ICRP's statement does not contain any explicit recommendations regarding the organ dose limit for the eye lens for public exposure. For the moment, no change is proposed. But, to be coherent in the overall approach, the current equivalent limit for the public might be lowered. A similar yardstick than in the former recommendation may be used, that is to say a reduction of 10 times lower than that for occupational exposure. In this context, additional data on potential scenarios for public exposure of the eye lens are necessary. This paper, mainly based on a literature study, aims to provide, as far as possible, an exhaustive list of the situations in which members of the public can be exposed at the level of the eye lens. Once these situations have been defined, some calculations, made to assess the associated doses to the eye lens, are presented. This literature study did not reveal any current situations where members of the public would receive significant radiation doses to the eye lens. Indeed, the situations in which the dose to the eye lens might reach around 1 mSv per year for the public are extremely rare. (authors)

  5. Measurements of eye lens doses in interventional radiology and cardiology: Final results of the ORAMED project

    International Nuclear Information System (INIS)

    Vanhavere, F.; Carinou, E.; Domienik, J.; Donadille, L.; Ginjaume, M.; Gualdrini, G.; Koukorava, C.; Krim, S.; Nikodemova, D.; Ruiz-Lopez, N.; Sans-Merce, M.; Struelens, L.

    2011-01-01

    Within the ORAMED project (Optimization of Radiation Protection of Medical Staff) a coordinated measurement program for occupationally exposed medical staff was performed in different hospitals in Europe ( (www.oramed-fp7.eu)). The main objective was to obtain a set of standardized data on extremity and eye lens doses for staff involved in interventional radiology and cardiology and to optimize radiation protection. Special attention was given to the measurement of the doses to the eye lenses. In this paper an overview will be given of the measured eye lens doses and the main influence factors for these doses. The measured eye lens doses are extrapolated to annual doses. The extrapolations showed that monitoring of the eye lens should be performed on routine basis.

  6. Staff exposure in pediatric interventional neuroradiology: focus on the operator's eye lens

    International Nuclear Information System (INIS)

    Bolomey, C.; Fasel, G.; Le Coultre, R.; Ryckx, N.

    2016-01-01

    Previously at 150 mSv year -1 , the ICRP now recommends limiting the equivalent dose to the eye lens to 20 mSv year -1 . For pediatric interventional neuroradiology, the exposure of the operator's eye lens may be increased by the use of a biplane fluoroscopy system and by the proximity of the physician to the patient. In practice, the efficiency of leaded glasses depends on many factors. This study addresses both aspects. First, the eye lens dose of a neuro-radiologist was measured during 12 procedures using 36 TLDs placed on his surgical cap. Secondly, in order to determine the efficiency of leaded glasses, measurements were carried out by reproducing the clinical conditions. A detector was placed on the left eye of a phantom representing the operator. Four pairs of leaded glasses were selected to test various parameters. During the 12 procedures, an individual dose equivalent Hp(0.07) of 45μSv was obtained for the eye lens closest to the tube. This study shows an eye lens dose to DAP ratio 5 times higher than for procedures performed on adult patients. The eye lens dose might be reduced by a factor of approximately 3 with the use of appropriate leaded glasses. The eye wear model with the most coverage reduces the dose by up to 50% more than the model with the least coverage. The addition of lateral protection increases the attenuation by up to 13% compared with the same model without side protection. (authors)

  7. Measurement of radiation dose to the eye-lens with bilateral whole brain irradiation

    International Nuclear Information System (INIS)

    Kim, Ki Hwan; Park, Charn Il; Kang, Wee Saing; Choo, Dong Woon

    1985-01-01

    In 40 patients with metastatic brain tumor and acute lymphoblastic leukemia received whole brain irradiation, the dose delivered to the eye lens was measured using T.L.D. chips applied on the eyes as usual shield. The dose to the eye lens was expressed the relative dose to the mid brain dose. Radiotherapy was administrated using Co-60 teletherapy with bilateral whole brain irradiation. The results are as follows: 1. The dose to the right eye from its incipient field is 16.6% of tumor dose while the dose to the same eye from the opposite field is 41.2%. On left eye, 19.2% from incipient field while 39.2% from the opposite field. 2. Total received dose to right and left eyes is 28.9%, 29.8% of tumor dose respectively. 3. Comparing lens shield group with orbit shield group dose is 22.5%, 15.8% of tumor dose, respectively. 4. The dose delivered to the eye lens in ipsilateral side depends upon internal scattering, location of lead shield and penetrating dose of lead in itself. The dose in contralateral side depends upon divergency of radiation beam and patient's malposition. 5. The dose to the eye lens should be less than 10% of tumor dose with adequate shield, also not missing the chance of leptomeningeal recurrence because of overshielding.

  8. Eye lens dosimetry for interventional procedures – Relation between the absorbed dose to the lens and dose at measurement positions

    International Nuclear Information System (INIS)

    Geber, Therese; Gunnarsson, Mikael; Mattsson, Sören

    2011-01-01

    This study investigated the relationship between the absorbed dose to the lens of the eye and the absorbed dose at different measurement positions near the eye of interventional radiologists. It also visualised the dose distribution inside the head, both when protective eyewear were used and without such protection. The best position for an eye lens dosimeter was found to be at the side of the head nearest to the radiation source, close to the eye. Positioning the dosimeter at the eyebrow could lead to an underestimation of the lens dose of as much as 45%. The measured dose distribution showed that the absorbed dose to the eye lenses was high compared to the other parts of the head, which stresses the importance of wearing protective eyewear. However, many models of eyewear were found to be deficient as the radiation could slip through at several places, e.g. at the cheek. The relationship between the absorbed dose to the lens and the kerma-area-product (P KA ) delivered to the patient was also studied.

  9. 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)

  10. Inter-specific and intraspecific eye lens protein differences in some sciaenid fishes from Goa coast

    Digital Repository Service at National Institute of Oceanography (India)

    Menezes, M.R.

    Soluble eye lens nuclei proteins of sciaenid fishes were studied by cellogel electrophoresis. Four distinct patterns characterized by the number of bands, mobility and staining intensity were observed. Morphological studies of these fishes showed...

  11. Opaque iris claw lens in a phakic eye to correct acquired diplopia

    NARCIS (Netherlands)

    Landesz, M; Worst, JGF; Rij, GV; Houtman, WA

    1997-01-01

    A 25-year-old man had diplopia caused by abducens nerve paresis on both sides after cranial injury. Because of the patient's reports of persistent diplopia after surgical correction, a specially manufactured, tinted iris claw lens was implanted in the left eye, with the crystalline lens in situ.

  12. Oral omega-6 essential fatty acid treatment in contact lens associated dry eye.

    OpenAIRE

    Kokke, K. H.; Morris, J. A.; Lawrenson, J.

    2008-01-01

    Symptoms of dry eye are commonly reported in contact lens wearers and are a frequent cause of non-tolerance. The purpose of the present study is to evaluate the effects of oral treatment with particular omega-6 fatty acids in the form of evening primrose oil (EPO) on subjective symptoms, ocular surface signs and tear film characteristic in patients with contact lens associated dry eye.

  13. 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.

  14. Treatment, material, care, and patient-related factors in contact lens-related dry eye.

    Science.gov (United States)

    Ramamoorthy, Padmapriya; Sinnott, Loraine T; Nichols, Jason J

    2008-08-01

    To examine the effect of general contact lens and material characteristics, care solutions, treatment, and patient-related factors on contact lens-related dry eye. The data were derived from the Contact Lens and Dry Eye Study, designed as a cross-sectional and nested case-control study including 360 subjects. In separate statistical models, logistic regression was used to examine general contact lens characteristics, specific hydrogel lens materials, care solutions, and patient-related factors associated with dry eye status (controlled for age, gender, and current treatments). Several factors were significantly associated with dry eye, including treatment factors such as a recent contact lens refitting (odds ratios [OR] = 5.75, 95% confidence intervals [CI] = 2.14 to 15.46) and use of artificial tears/rewetting drops (OR = 1.09, 95% CI = 1.02 to 1.16), in addition, currently worn materials including Food and Drug Administration (FDA) group II (OR = 2.98, 95% CI = 1.14 to 6.19) and IV (OR = 1.87, 95% CI = 1.08 to 3.24). Significant patient-related factors included decreased overall satisfaction (OR = 3.57, 95% CI = 2.08 to 5.88,), dry eye in the absence of contact lens wear (OR = 6.54, 95% CI = 2.57 to 16.62), reduced daily lens wear duration (OR = 1.16, 95% CI = 1.06 to 1.26), and reduced ability to wear lenses as long as desired (OR = 2.44, 95% CI = 1.30 to 4.54). Care solutions were not associated with contact lens-related dry eye. The strong association of common treatment factors with dry eye status in contact lens wearers suggests that these treatments are not entirely effective. The use of high water content materials was strongly related to dry eye in lens wearers, whereas care solutions were not. Contact lens-related dry eye was also associated with several patient-related factors such as greater ocular discomfort (without lenses), dissatisfaction, and inability to wear lenses for desired durations.

  15. Imaging properties of the light sword optical element used as a contact lens in a presbyopic eye model.

    Science.gov (United States)

    Petelczyc, K; Bará, S; Lopez, A Ciro; Jaroszewicz, Z; Kakarenko, K; Kolodziejczyk, A; Sypek, M

    2011-12-05

    The paper analyzes the imaging properties of the light sword optical element (LSOE) applied as a contact lens to the presbyopic human eye. We performed our studies with a human eye model based on the Gullstrand parameterization. In order to quantify the discussion concerning imaging with extended depth of focus, we introduced quantitative parameters characterizing output images of optotypes obtained in numerical simulations. The quality of the images formed by the LSOE were compared with those created by a presbyopic human eye, reading glasses and a quartic inverse axicon. Then we complemented the numerical results by an experiment where a 3D scene was imaged by means of the refractive LSOE correcting an artificial eye based on the Gullstrand model. According to performed simulations and experiments the LSOE exhibits abilities for presbyopia correction in a wide range of functional vision distances.

  16. Clinical assessment of diclofenac sodium eye drops in toric intraocular lens implantation

    Directory of Open Access Journals (Sweden)

    Yan Luo

    2013-05-01

    Full Text Available AIM:To evaluate the application of diclofenac sodium eye drops in toric intraocular lens implantation. METHODS: From January 2011 to February 2012, 38 eyes of 37 patients, who underwent toric intraocular lens implantation in this hospital, were randomly divided into diclofenac sodium eye drops group(trial groupand control group. Patient's degree of cooperation during surgery and inflammation postoperation after 1 day, 3,7, days, 1 month and 3 months were evaluated. RESULTS: Patient's degree of cooperation during surgery in the trial group(1.53±0.62was significantly better than in the control group(2.40±0.88, P<0.05. Inflammation reaction was gentle in the trial group 1 day postoperatively. CONCLUSION: Diclofenac sodium eye drops used during toric intraocular lens implantation can obviously alleviate eye irritation, and increase the cooperation of patients.

  17. Impact of radiation protection means on the dose to the lens of the eye while handling radionuclides in nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Bruchmann, Iris; Szermerski, Bastian; Geworski, Lilli [Medical School Hannover (Germany). Dept. for Radiation Protection and Medical Physics; Behrens, Rolf [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany)

    2016-07-01

    The human eye lens appears to be more radiosensitive than previously assumed. The reduction of the limit for the dose to the lens of the eye to 20 mSv per year has been passed in the current Euratom Directives (2013). Therefore, in this work the impact of laboratory glasses and X-ray protective goggles was investigated and reciprocal attenuation factors (i.e. transmission factors) for different nuclides (Tc-99m, I-131, Y-90, F-18 and Ga-68) were determined. The radionuclides in typical geometry (syringe, applicator) were positioned at a distance of 50 cm to the eyes of four Alderson-Head-Phantoms. Different dosemeters measuring H{sub p}(3) respective H{sub p}(0.07) were fixed to the eyes of the phantoms, either behind the glasses or without any protection means, respectively. The mean reciprocal attenuation factors were determined to be between unity for F-18 and I-131 using laboratory glasses (no attenuation effect) and < 0.01 for Y-90 using X-ray protective goggles. All other results were between these extremes. It has been shown, that prospective doses to the lens of the eye can be reduced significantly by using appropriate radiation protection means, especially for those dose-relevant beta radiation emitting nuclides such as Y-90.

  18. Telomere Attrition in Human Lens Epithelial Cells Associated with Oxidative Stress Provide a New Therapeutic Target for the Treatment, Dissolving and Prevention of Cataract with N-Acetylcarnosine Lubricant Eye Drops. Kinetic, Pharmacological and Activity-Dependent Separation of Therapeutic Targeting: Transcorneal Penetration and Delivery of L-Carnosine in the Aqueous Humor and Hormone-Like Hypothalamic Antiaging Effects of the Instilled Ophthalmic Drug Through a Safe Eye Medication Technique.

    Science.gov (United States)

    Babizhayev, Mark A; Yegorov, Yegor E

    2016-01-01

    Visual impairment broadly impacts the ability of affected people to maintain their function and to remain independent during their daily occupations as they grow older. Visual impairment affects survival of older patients, quality of life, can affect a person's self-ranking of health, may be associated with social and functional decline, use of community support services, depression, falls, nursing home placement, and increased mortality. It has been hypothesized that senile cataract may serve as a marker for generalised tissue aging, since structural changes occurring in the proteins of the lens during cataract formation are similar to those which occur elsewhere as part of the aging process. The published analysis revealed a strong age-dependent relationship between undergoing cataract surgery and subsequent mortality. Nuclear opacity, particularly severe nuclear opacity, and mixed opacities with nuclear were significant predictors of mortality independent of body mass index, comorbid conditions, smoking, age, race, and sex. The lens opacity status is considered as an independent predictor of 2-year mortality, an association that could not be explained by potential confounders. Telomeres have become important biomarkers for aging as well as for oxidative stress-related disease. The lens epithelium is especially vulnerable to oxidative stress. Oxidative damage to the cuboidal epithelial cells on the anterior surface of the lens mediated by reactive oxygen species and phospholipid hydroperoxides can precede and contribute to human lens cataract formation. The erosion and shortening of telomeres in human lens epithelial cells in the lack of telomerase activity has been recognized as a primary cause of premature lens senescence phenotype that trigger human cataractogenesis. In this study we aimed to be focused on research defining the mechanisms that underlie linkages among telomere attrition in human lens epithelial cells associated with oxidative stress, biology of

  19. 'Yellow lens' eyes of a stomiatoid deep-sea fish, Malacosteus niger.

    Science.gov (United States)

    Somiya, H

    1982-07-22

    Bright yellow lenses were found in the eyes of the stomiatoid deep-sea fish, Malacosteus niger Ayres. The optical properties of the yellow lens and the retinal specializations in the eyes were examined. Absorption spectra of the yellow lens revealed two peaks at wavelengths 425 and 460 nm. The photoreceptors were all rods and were arranged in two superimposed layers. An astaxanthin-type retinal tapetum was observed in the pigment epithelium. Some chemical evidence is presented showing that the tapetal material is an astaxanthin ester. The ecological significance of the yellow lens is discussed in connection with that of Malacosteus' orbital light organ which has a reddish filter.

  20. Ray tracing for inhomogeneous media applied to the human eye

    Science.gov (United States)

    Diaz-Gonzalez, G.; Iturbe-Castillo, M. D.; Juarez-Salazar, R.

    2017-08-01

    Inhomogeneous or gradient index media exhibit a refractive index varying with the position. This kind of media are very interesting because they can be found in both synthetic as well as real life optical devices such as the human lens. In this work we present the development of a computational tool for ray tracing in refractive optical systems. Particularly, the human eye is used as the optical system under study. An inhomogeneous medium with similar characteristics to the human lens is introduced and modeled by the so-called slices method. The useful of our proposal is illustrated by several graphical results.

  1. Oral omega-6 essential fatty acid treatment in contact lens associated dry eye.

    Science.gov (United States)

    Kokke, Karolien H; Morris, Judith A; Lawrenson, John G

    2008-06-01

    Symptoms of dry eye are commonly reported in contact lens wearers and are a frequent cause of non-tolerance. The purpose of the present study is to evaluate the effects of oral treatment with particular omega-6 fatty acids in the form of evening primrose oil (EPO) on subjective symptoms, ocular surface signs and tear film characteristic in patients with contact lens associated dry eye. The study design was randomised, double-masked and placebo controlled. 76 female soft contact lens wearers were treated for 6 months with either EPO or placebo (olive oil). Subjects underwent three examinations (baseline, 3 and 6 months). At each examination subjects were given a questionnaire relating to lens comfort and dry eye symptoms and underwent a series of tests of tear film characteristics (tear meniscus height, break-up time), meibomian gland function (lipid layer thickness and quality) and ocular surface parameters (hyperaemia and staining). The EPO group showed a significant improvement in the specific symptom of 'dryness' at 3 and 6 months (porally administered omega-6 fatty acids in alleviating dry eye symptoms and improving overall lens comfort in patients suffering from contact lens associated dry eye.

  2. Wide-field schematic eye models with gradient-index lens.

    Science.gov (United States)

    Goncharov, Alexander V; Dainty, Chris

    2007-08-01

    We propose a wide-field schematic eye model, which provides a more realistic description of the optical system of the eye in relation to its anatomical structure. The wide-field model incorporates a gradient-index (GRIN) lens, which enables it to fulfill properties of two well-known schematic eye models, namely, Navarro's model for off-axis aberrations and Thibos's chromatic on-axis model (the Indiana eye). These two models are based on extensive experimental data, which makes the derived wide-field eye model also consistent with that data. A mathematical method to construct a GRIN lens with its iso-indicial contours following the optical surfaces of given asphericity is presented. The efficiency of the method is demonstrated with three variants related to different age groups. The role of the GRIN structure in relation to the lens paradox is analyzed. The wide-field model with a GRIN lens can be used as a starting design for the eye inverse problem, i.e., reconstructing the optical structure of the eye from off-axis wavefront measurements. Anatomically more accurate age-dependent optical models of the eye could ultimately help an optical designer to improve wide-field retinal imaging.

  3. Radiation exposure of the radiologist's eye lens during CT-guided interventions.

    Science.gov (United States)

    Heusch, Philipp; Kröpil, Patric; Buchbender, Christian; Aissa, Joel; Lanzman, Rotem S; Heusner, Till A; Ewen, Klaus; Antoch, Gerald; Fürst, Günther

    2014-02-01

    In the past decade the number of computed tomography (CT)-guided procedures performed by interventional radiologists have increased, leading to a significantly higher radiation exposure of the interventionalist's eye lens. Because of growing concern that there is a stochastic effect for the development of lens opacification, eye lens dose reduction for operators and patients should be of maximal interest. To determine the interventionalist's equivalent eye lens dose during CT-guided interventions and to relate the results to the maximum of the recommended equivalent dose limit. During 89 CT-guided interventions (e.g. biopsies, drainage procedures, etc.) measurements of eye lens' radiation doses were obtained from a dedicated dosimeter system for scattered radiation. The sensor of the personal dosimeter system was clipped onto the side of the lead glasses which was located nearest to the CT gantry. After the procedure, radiation dose (µSv), dose rate (µSv/min) and the total exposure time (s) were recorded. For all 89 interventions, the median total exposure lens dose was 3.3 µSv (range, 0.03-218.9 µSv) for a median exposure time of 26.2 s (range, 1.1-94.0 s). The median dose rate was 13.9 µSv/min (range, 1.1-335.5 µSv/min). Estimating 50-200 CT-guided interventions per year performed by one interventionalist, the median dose of the eye lens of the interventional radiologist does not exceed the maximum of the ICRP-recommended equivalent eye lens dose limit of 20 mSv per year.

  4. Transglutaminase involvement in UV-A damage to the eye lens

    International Nuclear Information System (INIS)

    Weinreb, Orly; Dovrat, A.

    1996-01-01

    Solar radiation is believed to be one of the major environmental factors involved in lens cataractogenesis. The purpose of the study was to investigate the mechanisms by which UV-A at 365 nm causes damage to the eye lens. Bovine lenses were placed in special culture cells for pre-incubation of 24 hr. The lenses were positioned so that the anterior surface faced the incident UV-A radiation source and were maintained in the cells during irradiation. After irradiation, lens optical quality was monitored throughout the culture period and lens epithelium, cortex and nuclear samples were taken for biochemical analysis. Transglutaminase activity in the lens was affected by the radiation. The activity of transglutaminase in lens epithelium cortex and nucleus increased as a result of the irradiation and then declined towards control levels during the culture period, as the lens recovered from the UV-A damage. Specific lens proteins αB and βB1 crystallins (the enzyme substrates) were analyzed by SDS polyacrylamid gel electrophoreses and immunoblotting with specific antibodies. Seventy-two hours after irradiation of 44.8 J cm -2 UV-A, αB crystallins were affected as was shown by the appearance of aggregation and degradation products. Some protein changes seem to be reversible. It appears that transglutaminase may be involved in the mechanism by which UV-A causes damage to the eye lens. (Author)

  5. The Management of Refractory Dry Eye With Semi-Scleral Contact Lens.

    Science.gov (United States)

    Yuksel, Erdem; Bilgihan, Kamil; Novruzlu, Şahin; Yuksel, Nilay; Koksal, Murat

    2016-05-19

    We presented a case of refractory dry eye management with semi-scleral contact lens. Dry eye was associated with facial nerve (cranial nerve VII) palsy as a result of cerebellopontine angle tumor surgery. She was treated with several topical treatments and punctal plug. Despite the treatments, her symptoms still persisted. Her ophthalmic examination revealed scleral exposure because of lagophthalmos, conjunctival hyperemia, corneal debris, scar, and diffuse punctate epitheliopathy on her right eye. Lissamine green staining showed diffuse conjunctival and corneal staining. Therapeutic semi-scleral lenses were fitted. The corneal findings were resolved and the quality of patient life was improved with the aid of semi-scleral lens after 3 months.

  6. Conjunctival impression cytology versus routine tear function tests for dry eye evaluation in contact lens wearers.

    Science.gov (United States)

    Kumar, Prachi; Bhargava, Rahul; Arora, Yogesh C; Kaushal, Sidharth; Kumar, Manjushri

    2015-01-01

    Prolonged contact lens wear is often accompanied by dryness of the eyes. The aim of this study was to compare conjunctival impression cytology (CIC) and tear film tests such as tear film break up time (TBUT) and Schirmer test for dry eye evaluation in contact lens wearers and measure their correlation with dry eye symptoms. A case control study was done at three referral eye centers. The eyes of 230 contact lens users were compared to 250 eyes of age- and sex-matched controls. Participants were recruited based on their response to a questionnaire of dry eye symptoms, (Dry Eye Scoring System, DESS(©)) and measurements of TBUT, Schirmer test, and CIC was done. A correlation analysis between symptom severity and tear film tests was performed. Pearson's coefficient, R(2) > 0.5 was considered significant. As compared to controls (r (2) = 0.010), Nelson grade correlated significantly with dry eye symptoms (r (2) = 0.765), among cases. However, there was moderate correlation between dry eye symptoms, Schirmer test, and TBUT (r (2) = 0.557 and 0.530, respectively) among cases and a weak correlation among controls (r (2) = 0.130 and 0.054, respectively). The sensitivity of TBUT was 86.4%, specificity was 82.4%, positive likelihood ratio (LR) was 4.50 [95% confidence interval (CI) 3.46-5.85)], and negative LR was 0.09. The sensitivity of the Schirmer test was 48.2%, specificity 88%, LR 2.12 (95% CI 1.48-2.96), and negative LR 0.83. CIC correlates better than Schirmer and TBUT with dry eye symptoms. It may be the most appropriate test for dry-eye evaluation in contact lens wearers.

  7. Oral omega-3 fatty acid treatment for dry eye in contact lens wearers.

    Science.gov (United States)

    Bhargava, Rahul; Kumar, Prachi

    2015-04-01

    The aim of this study was to evaluate the effect of dietary omega-3 fatty acid (O3FA) supplementation on dry eye symptoms, tear film tests, and conjunctival impression cytology in patients with contact lens wear-associated dry eye. In this randomized, double-blind, multicentric trial, contact lens wearers (n = 496) were randomized to receive either O3FAs or placebo capsules (corn oil) twice daily for 6 months. Subjects underwent examinations at baseline, 3 months, and 6 months. At each visit, a questionnaire of dry eye symptoms and lens wear comfort was administered. Subjects further underwent measurement of tear film break-up time (TBUT) and a Schirmer test. Conjunctival impression cytology was performed by the transfer method. Improvement in symptoms and lens wear comfort were primary outcome measures. Changes from baseline in TBUT, Schirmer, and Nelson grade at 6 months were secondary outcome measures. The mean improvement in symptom score in the O3FA group was 4.7 ± 2 (2.0) as compared with 0.5 ± 2 (0.9) in the placebo group (P dry eye symptoms, improving lens wear comfort, and cytological changes in contact lens wearers.

  8. 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.

  9. Radiation exposure to the eye lens of orthopaedic surgeons during various orthopaedic procedures

    International Nuclear Information System (INIS)

    Romanova, K.; Alyakov, M.; Vassileva, J.

    2015-01-01

    The aim of the present study was to assess the radiation dose to the eye lens of orthopaedic surgeons during various orthopaedic procedures and to make efforts to ensure that radiation protection is optimised. The study was performed for Fractura femoris and Fractura cruris procedures performed in orthopaedic operating theatres, as well as for fractures of wrist, ankle and hand/ shoulder performed in the emergency trauma room. The highest mean value of the eye lens dose of 47.2 μSv and higher mean fluoroscopy time of 3 min, as well as the corresponding highest maximum values of 77.1 μSv and 5.0 min were observed for the Fractura femoris procedure performed with the Biplanar 500e fluoroscopy systems. At a normal workload, the estimated mean annual dose values do not exceed the annual occupational dose limit for the lens of eye, but at a heavy workload in the department, this dose limit could be achieved or exceeded. The use of protective lead glasses is recommended as they could reduce the radiation exposure of the lens of the eye. The phantom measurements demonstrated that the use of half-dose mode could additionally reduce dose to the operator's eye lens. (authors)

  10. Growth of the human lens in the Indian adult population: Preliminary observations

    Directory of Open Access Journals (Sweden)

    Ashik Mohamed

    2012-01-01

    Full Text Available Context: The eye lens grows throughout life by the addition of new cells inside the surrounding capsule. How this growth affects the properties of the lens is essential for understanding disorders such as cataract and presbyopia. Aims: To examine growth of the human lens in the Indian population and compare this with the growth in Western populations by measuring in vitro dimensions together with wet and dry weights. Settings and Design: The study was conducted at the research wing of a tertiary eye care center in South India and the study design was prospective. Materials and Methods: Lenses were removed from eye bank eyes and their dimensions measured with a digital caliper. They were then carefully blotted dry and weighed before being placed in 5% buffered formalin. After 1 week fixation, the lenses were dried at 80 °C until constant weight was achieved. The constant weight was noted as the dry weight of the lens. Statistical Analysis Used: Lens parameters were analyzed as a function of age using linear and logarithmic regression methods. Results: Data were obtained for 251 lenses, aged 16-93 years, within a median postmortem time of 22 h. Both wet and dry weights increased linearly at 1.24 and 0.44 mg/year, respectively, throughout adult life. The dimensions also increased continuously throughout this time. Conclusions: Over the age range examined, lens growth in the Indian population is very similar to that in Western populations.

  11. [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.

  12. Study of the structure of buffalo's eye lens and scleroretinal rim in Tabriz by ultrasonography

    Directory of Open Access Journals (Sweden)

    GH Assadnassab

    2011-05-01

    Full Text Available In this study, ultrasonographic condition of lens and posterior wall of buffalo's eye in Tabriz area were investigated due to their important role in vision and also measurements were made in anterior-posterior axial B-mode display methods. The ultrasonographic images were similar to the images obtained from other particularly the cow. Total thickness of the lens was 1.133 ± 0.052 cm with the thickness being 1.135 ± 0.052 cm in the right eye and 1.132 ± 0.053 cm in the left eye. Thickness of the posterior wall of the right and left eyes were 1.677 ± 0.042 mm and 1.672 ± 0.041 mm respectively with the total thickness of the posterior wall measuring 1.674 ± 0.040 mm. There was no significant difference between the left and right eyes regarding these parameters.

  13. Influence of different types of phantoms on the calibration of dosemeters for eye lens dosimetry

    International Nuclear Information System (INIS)

    Yoshitomi, H.; Kowatari, M.

    2016-01-01

    Both a cylinder and a slab phantom have been recommended to be used as calibration phantoms for eye lens dosimetry in the International Atomic Energy Agency TECDOC. This study describes investigations on the influence of the type of phantom on the calibration of dosemeters. In order to fulfil the purpose, backscatter radiation from practically used water-filled phantoms was evaluated by calculations and experiments. For photons, the calculations showed that the cylinder phantom had 10 % lower backscattered effect at maximum than a slab phantom, and simulated well the backscattered effect of the human head or neck to within ±10 %. The irradiation results of non-filtered optically stimulated luminescence and radio-photoluminescence glass dosemeters indicated that the differences of the calibration factors between the two types of phantoms were up to 20 and 10 %, respectively, reflecting the response to backscattered photons. For electrons, no difference was found between the two types of phantoms. (authors)

  14. Dosimetry studies with 32P source and correlation of skin and eye lens doses

    International Nuclear Information System (INIS)

    Kumar, Munish; Gaonkar, U.P.; Koul, D.K.; Datta, D.; Saxena, S.K.; Kumar, Yogendra; Dash, A.

    2018-01-01

    Beta particles are one of the major contributors toward skin and eye lens doses at facilities handling beta sources. These sources find applications in industry, pharmaceuticals as well as in brachytherapy applications. The beta particles having maximum (E max ) energy > 0.07 MeV are capable of delivering skin dose whereas beta particles having maximum (E max ) energy > 0.7 MeV may also contribute towards dose to eye lens. Studies are performed using 32 P beta source as its maximum beta energy (E max ) is such that for sources having (E max ) of 1.71 MeV or beyond, there can be substantial contribution towards dose to eye lens even the dose limit recommended for skin is followed

  15. Radiation exposure to the lens of the eye in temporal bone radiography

    International Nuclear Information System (INIS)

    Paix, D.

    1980-01-01

    Both the sensitivity of the eye to radiation cataract and the doses delivered to it in petrous bone examination are ill-defined. However, the following guidelines are suggested: (1) radiation cataract is unlikely to be a contraindication in patients over 50; (2) lens exposure per film when using an AP projection should be about 5m Gy; this may be reduced tenfold when tomographic movements permit the use of eye shields containing 1mm of lead; (3) projections which do not include the eyes in the direct beam should entail lens doses of 0.2m Gy or less; (4) steps should be taken to prevent the accumulated dose to the patient's lens from reaching 300m Gy per year or 15 Gy in all

  16. Acanthamoeba keratitis in a non-contact lens wearer with human immunodeficiency virus

    DEFF Research Database (Denmark)

    Hansen, Birgitte Rønde; Kronborg, Gitte

    2003-01-01

    , and was treated with various topical antibiotics and steroids. 13 months after symptom onset the eye was removed owing to serious scarring of cornea and unbearable pain. Microbiological and histopathological examination of the cornea showed Acanthamoeba. In non-contact lens wearers suffering from Acanthamoeba......Acanthamoeba keratitis is potentially blinding and often associated with contact lens wearing. A human immunodeficiency virus (HIV)-positive patient, a non-contact lens wearer, presented with keratitis. She experienced a protracted course of disease, characterized by exacerbations and remissions...

  17. Radiation-induced eye lens changes and risk for cataract in interventional cardiology.

    Science.gov (United States)

    Ciraj-Bjelac, O; Rehani, M; Minamoto, A; Sim, K H; Liew, H B; Vano, E

    2012-01-01

    Recent studies have reported a significant increase in eye lens opacities among staff in the cardiac catheterization laboratory but indicated further studies are needed to confirm the findings. To evaluate the prevalence of opacities in eyes of cardiologists, radiographers and nurses working in interventional cardiology. The eyes of 52 staff in interventional cardiology facilities and 34 age- and sex-matched unexposed controls were screened in a cardiology conference held in Kuala Lumpur by dilated slit-lamp examination, and posterior lens changes were graded. Individual cumulative lens X-ray exposures were calculated from responses to a questionnaire in terms of workload and working practice. The prevalence of posterior lens opacities among interventional cardiologists was 53%, while in nurses and radiographers it was 45%. Corresponding relative risks were 2.6 (95% CI: 1.2-5.4) and 2.2 (95% CI: 0.98-4.9), for interventional cardiologists and support staff, respectively. This study confirms a statistically significant increase in radiation-associated posterior lens changes in the eyes of interventional cardiology staff. Copyright © 2012 S. Karger AG, Basel.

  18. Metamaterial-based half Maxwell fish-eye lens for broadband directive emissions

    Science.gov (United States)

    Dhouibi, Abdallah; Nawaz Burokur, Shah; de Lustrac, André; Priou, Alain

    2013-01-01

    The broadband directive emission from a metamaterial surface is numerically and experimentally reported. The metasurface, composed of non-resonant complementary closed ring structures, is designed to obey the refractive index of a half Maxwell fish-eye lens. A planar microstrip Vivaldi antenna is used as transverse magnetic polarized wave launcher for the lens. A prototype of the lens associated with its feed structure has been fabricated using standard lithography techniques. To experimentally demonstrate the broadband focusing properties and directive emissions, both the far-field radiation patterns and the near-field distributions have been measured. Measurements agree quantitatively and qualitatively with theoretical simulations.

  19. Arthropods affecting the human eye.

    Science.gov (United States)

    Panadero-Fontán, Rosario; Otranto, Domenico

    2015-02-28

    Ocular infestations by arthropods consist in the parasitization of the human eye, either directly (e.g., some insect larvae causing ophthalmomyiasis) or via arthropods feeding on lachrymal/conjunctival secretions (e.g., some eye-seeking insects, which also act as vectors of eye pathogens). In addition, demodicosis and phthiriasis may also cause eye discomfort in humans. Ophthalmomyiasis by larvae of the families Oestridae, Calliphoridae and Sarcophagidae, are frequent causative agents of human ocular infestations. Over the last decades, the extensive use of macrocyclic lactones in cattle has reduced the frequency of infestations by Hypoderma bovis and Hypoderma lineatum (family Oestridae), and consequently, human infestations by these species. A prompt diagnosis of ocular myiasis (e.g., by serological tests) is pivotal for positive prognoses, particularly when the larvae are not detectable during the ophthalmologic examination. Molecular diagnoses may also assist physicians and parasitologists in achieving time-efficient diagnoses of infestations by Oestridae causing myiasis. Finally, due to widespread international travel to exotic destinations, cases of myiasis are increasing in non-endemic areas, therefore requiring physicians to acquire a profound knowledge of the clinical symptoms linked to these infestations to prevent costly, inappropriate treatments or severe complications. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Human lens colouration, age and cataract

    International Nuclear Information System (INIS)

    Truscott, R.J.W.; Garner, B.; Hood, B.

    1999-01-01

    Full text: The human lens biosynthesises UV filter compounds which effectively remove light in the 300-400nm band. These chemicals are present either as an aid to visual acuity, or to filter out damaging UV radiation. The primate UV filters are 3-hydroxykynurenine analogues derived from the metabolism of tryptophan. We have recently demonstrated that these endogenous UV filters are not innocuous, but are in fact capable of binding to proteins, including the crystalline proteins which make up the bulk of the lens. Thus, over time, the levels of protein - bound UV filters increase and this results in the human lens becoming progressively more yellow as we age. This colouration affects our colour vision and it may also be responsible for the brown colour of lenses which is the hallmark of age-related nuclear cataract. An understanding of the intrinsic instability of the endogenous UV filters, combined with changes in the internal transport of these and other small molecular weight compounds including antioxidants, such as glutathione, is allowing us to gain an insight into the processes responsible for the development of age-related cataract: the major cause of world blindness

  1. Pseudophakic hyperopia in nanophthalmic eyes managed by a posterior chamber implantable collamer lens

    Directory of Open Access Journals (Sweden)

    Kothari Kulin

    2011-01-01

    Full Text Available We report a case of a bilateral posterior chamber implantable collamer lens (ICL implantation post-clear lens extraction, to reduce the residual hyperopia, in a patient with nanophthalmic eyes. A 30-year-old female patient, keen to reduce her dependency on glasses and contact lenses, came to our refractive surgery department. Her refractive error was +12.0 and +12.5 diopters in the right and left eye, respectively, with steep corneas on keratometry and a shallow anterior chamber depth. She underwent clear lens extraction with implantation of +35.0 D and +40.0 D IOL in the right eye and left eye, respectively. Her post-operative best-corrected visual acuity was 20/30 with +8.5 D in the right eye and +6 D in the left. She underwent bilateral ICL implantation. Postoperatively after 6 months, her unaided visual acuity was 20/30 in both eyes. In conclusion, ICL implantation can be considered to correct residual hypermetropic ametropia in pseudophakic eyes when other options have limitations.

  2. 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

  3. The influence of crystalline lens accommodation on post-saccadic oscillations in pupil-based eye trackers

    NARCIS (Netherlands)

    Nyström, Marcus; Andersson, Richard; Magnusson, Måns; Pansell, Tony; Hooge, Ignace; Hooge, Ignace

    2015-01-01

    It is well known that the crystalline lens (henceforth lens) can oscillate (or 'wobble') relative to the eyeball at the end of saccades. Recent research has proposed that such wobbling of the lens is a source of post-saccadic oscillations (PSOs) seen in data recorded by eye trackers that estimate

  4. A medieval fallacy: the crystalline lens in the center of the eye.

    Science.gov (United States)

    Leffler, Christopher T; Hadi, Tamer M; Udupa, Akrithi; Schwartz, Stephen G; Schwartz, Daniel

    2016-01-01

    To determine whether, as most modern historians have written, ancient Greco-Roman authors believed the crystalline lens is positioned in the center of the eye. Historians have written that statements about cataract couching by Celsus, or perhaps Galen of Pergamon, suggested a centrally located lens. Celsus specifically wrote that a couching needle placed intermediate between the corneal limbus and the lateral canthus enters an empty space, presumed to represent the posterior chamber. Ancient ophthalmic literature was analyzed to understand where these authors believed the crystalline lens was positioned. In order to estimate where Celsus proposed entering the eye during couching, we prospectively measured the distance from the temporal corneal limbus to the lateral canthus in 30 healthy adults. Rufus of Ephesus and Galen wrote that the lens is anterior enough to contact the iris. Galen wrote that the lens equator joins other ocular structures at the corneoscleral junction. In 30 subjects, half the distance from the temporal corneal limbus to the lateral canthus was a mean of 4.5 mm (range: 3.3-5.3 mm). Descriptions of couching by Celsus and others are consistent with pars plana entry of the couching needle. Anterior angulation of the needle would permit contact of the needle with the lens. Ancient descriptions of anatomy and couching do not establish the microanatomic relationships of the ciliary region with any modern degree of accuracy. Nonetheless, ancient authors, such as Galen and Rufus, clearly understood that the lens is located anteriorly. There is little reason to believe that Celsus or other ancient authors held a variant understanding of the anatomy of a healthy eye. The notion of the central location of the lens seems to have arisen with Arabic authors in 9th century Mesopotamia, and lasted for over 7 centuries.

  5. Complications and visual outcomes after glued foldable intraocular lens implantation in eyes with inadequate capsules.

    Science.gov (United States)

    Kumar, Dhivya Ashok; Agarwal, Amar; Packiyalakshmi, Sathiya; Jacob, Soosan; Agarwal, Athiya

    2013-08-01

    To evaluate the complications and visual outcomes of glued intrascleral-fixated foldable intraocular lens (IOL) in eyes with deficient capsules. Dr Agarwal's Eye Hospital and Eye Research Centre, Chennai, India. Case series. Data were evaluated from the records of patients with a primary glued foldable IOL for intraoperative capsular loss or subluxated lens or secondary glued foldable IOL for aphakia. Exclusion criteria included preoperative glaucoma, aniridia, macular scar, traumatic subluxation, combined surgeries, incomplete operative medical records, and postoperative follow-up less than 6 months. The intraoperative and postoperative complication rates, reoperation rate, and visual outcomes were analyzed. The study comprised 208 eyes (185 patients). The mean follow-up was 16.7 months ± 10.2 (SD). The intraoperative complications were hyphema (0.4%), haptic breakage (0.4%), and deformed haptics (0.9%). Early complications occurred in 29 eyes (13.9%) and included corneal edema (5.7%), epithelial defect (1.9%), and grade 2 anterior chamber reaction (2.4%). Late complications occurred in 39 eyes (18.7%) and included optic capture (4.3%), IOL decentration (3.3%), haptic extrusion (1.9%), subconjunctival haptic (1.4%), macular edema (1.9%), and pigment dispersion (1.9%). Reoperation was required in 16 eyes (7.7%). Haptic position was altered in eyes with IOL decentration. Corrected distance visual acuity (CDVA) improved or remained unchanged in 84.6% of eyes. The postoperative CDVA was 20/40 or better and 20/60 or better in 38.9% and 48.5% of eyes, respectively. The foldable glued-IOL procedure showed satisfactory visual outcomes without serious complications. Intraocular lens decentration was due to haptic-related problems. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Xiao-Guang Dong

    2013-04-01

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

  7. 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.)

  8. Photodamaging mechanisms of the eye structure: the aggregates appearance at UV-illumination of lens proteins

    International Nuclear Information System (INIS)

    El'chaninov, V.V.; Fedorovich, I.B.

    1989-01-01

    UV-light injury of individual crystallines (water soluble proteins of the cattle eye crystalline lens) were studied by SDS PSSG technique. Photodamage resulted in olygomer formation. The appearance of high molecular aggregates with the molecular mass as large as 10 5 D were seen in all fractions of the crystalline

  9. Dose to the lens of the eye when scanning internal auditory meati

    International Nuclear Information System (INIS)

    English, P.T.

    1988-01-01

    With particular reference to the lens of the eye when CT scanning the internal auditory meati (IAMs), the practice of angling the scanner gantry to avoid the orbits completely justifies itself, reducing dosage to 5% of that given by a pre-orbital scan. (author)

  10. Eye evolution: lens and cornea as an upgrade of animal visual system

    Czech Academy of Sciences Publication Activity Database

    Jonášová, Kristýna; Kozmik, Zbyněk

    2008-01-01

    Roč. 19, č. 2 (2008), s. 71-81 ISSN 1084-9521 R&D Projects: GA AV ČR IAA500520604; GA MŠk(CZ) 1M0520 Institutional research plan: CEZ:AV0Z50520514 Keywords : eye * lens * cornea Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.528, year: 2008

  11. The effect of melatonin on eye lens of rats exposed to ultraviolet radiation.

    Science.gov (United States)

    Anwar, M M; Moustafa, M A

    2001-05-01

    We investigated the influence of exogenously administered melatonin on adult rats eye lenses exposed to ultraviolet radiation (UV) A and B ranging from 356-254 nm irradiation at 8 microW/cm(2). Rats exposed to this range of UV for 15 min for one week showed a significant (PUV-radiation significantly (PUV irradiation, may be the main cause of lens opacification. Melatonin injection with radiation significantly reduced (Pradiation, SOD and GSH-Px enzyme activities increased significantly (PUV radiation was as effective as melatonin treatment concurrent with UV irradiation. We conclude that melatonin may protect the eye lens from the damaging effects of UV exposure, and its actions protect lens from oxidative stress, elevating Ca(2+) levels, which are considered as an important causes of cataractogenesis.

  12. 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)

  13. Eye lens membrane junctional microdomains: a comparison between healthy and pathological cases

    Energy Technology Data Exchange (ETDEWEB)

    Buzhynskyy, Nikolay; Scheuring, Simon [Institut Curie, Equipe Inserm Avenir, UMR168-CNRS, 26 Rue d' Ulm, 75248 Paris Cedex 05 (France); Sens, Pierre [ESPCI, CNRS-UMR 7083, 75231 Paris (France); Behar-Cohen, Francine, E-mail: simon.scheuring@curie.fr [UMRS Inserm 872, Universite Paris Descartes, Centre de Recherches des Cordeliers, 15 rue de l' Ecole de Medecine, 75270 Paris Cedex 06 (France)

    2011-08-15

    The eye lens is a transparent tissue constituted of tightly packed fiber cells. To maintain homeostasis and transparency of the lens, the circulation of water, ions and metabolites is required. Junctional microdomains connect the lens cells and ensure both tight cell-to-cell adhesion and intercellular flow of fluids through a microcirculation system. Here, we overview membrane morphology and tissue functional requirements of the mammalian lens. Atomic force microscopy (AFM) has opened up the possibility of visualizing the junctional microdomains at unprecedented submolecular resolution, revealing the supramolecular assembly of lens-specific aquaporin-0 (AQP0) and connexins (Cx). We compare the membrane protein assembly in healthy lenses with senile and diabetes-II cataract cases and novel data of the lens membranes from a congenital cataract. In the healthy case, AQP0s form characteristic square arrays confined by connexons. In the cases of senile and diabetes-II cataract patients, connexons were degraded, leading to malformation of AQP0 arrays and breakdown of the microcirculation system. In the congenital cataract, connexons are present, indicating probable non-membranous grounds for lens opacification. Further, we discuss the energetic aspects of the membrane organization in junctional microdomains. The AFM hence becomes a biomedical nano-imaging tool for the analysis of single-membrane protein supramolecular association in healthy and pathological membranes.

  14. Eye lens membrane junctional microdomains: a comparison between healthy and pathological cases

    Science.gov (United States)

    Buzhynskyy, Nikolay; Sens, Pierre; Behar-Cohen, Francine; Scheuring, Simon

    2011-08-01

    The eye lens is a transparent tissue constituted of tightly packed fiber cells. To maintain homeostasis and transparency of the lens, the circulation of water, ions and metabolites is required. Junctional microdomains connect the lens cells and ensure both tight cell-to-cell adhesion and intercellular flow of fluids through a microcirculation system. Here, we overview membrane morphology and tissue functional requirements of the mammalian lens. Atomic force microscopy (AFM) has opened up the possibility of visualizing the junctional microdomains at unprecedented submolecular resolution, revealing the supramolecular assembly of lens-specific aquaporin-0 (AQP0) and connexins (Cx). We compare the membrane protein assembly in healthy lenses with senile and diabetes-II cataract cases and novel data of the lens membranes from a congenital cataract. In the healthy case, AQP0s form characteristic square arrays confined by connexons. In the cases of senile and diabetes-II cataract patients, connexons were degraded, leading to malformation of AQP0 arrays and breakdown of the microcirculation system. In the congenital cataract, connexons are present, indicating probable non-membranous grounds for lens opacification. Further, we discuss the energetic aspects of the membrane organization in junctional microdomains. The AFM hence becomes a biomedical nano-imaging tool for the analysis of single-membrane protein supramolecular association in healthy and pathological membranes.

  15. Reliability of eye lens dosimetry in workers of a positron emission tomography radiopharmaceutical production facility

    International Nuclear Information System (INIS)

    Silva, Teógenes A. da; Guimarães, Margarete C.; Meireles, Leonardo S.; Teles, Luciana L.D.; Lacerda, Marco Aurélio S.

    2016-01-01

    A new regulatory statement was issued concerning the eye lens radiation protection of persons in planned exposures. A debate was raised on the adequacy of the dosimetric quantity and on its method of measurement. The aim of this work was to establish the individual monitoring procedure with the EYE-D™ holder and a MCP-N LiF:Mg,Cu,P thermoluminescent chip detector for measuring the personal dose equivalent H_p(3) in workers of a Positron Emission Tomography Radiopharmaceutical Production Facility. - Highlights: • New regulatory statement was issued concerning eye lens radiation protection. • The calibration procedure of dosimeters for measuring H_p(3) was studied on a slab and cylindrical phantoms. • H_p(3) measurements in workers in a radiopharmaceutical production facility were done.

  16. Measurements of eye lens doses in interventional cardiology using OSL and electronic dosemeters

    International Nuclear Information System (INIS)

    Sanchez, R.M.; Vano, E.; Fernandez, J.M.; Ginjaume, M.; Duch, M.A.

    2014-01-01

    The purpose of this paper is to test the appropriateness of OSL and electronic dosemeters to estimate eye lens doses at interventional cardiology environment. Using TLD as reference detectors, personal dose equivalent was measured in phantoms and during clinical procedures. For phantom measurements, OSL dose values resulted in an average difference of 215 % vs. TLD. Tests carried out with other electronic dosemeters revealed differences up to ±20 % versus TLD. With dosemeters positioned outside the goggles and when TLD doses were >20 μSv, the average difference OSL vs. TLD was 29 %. Eye lens doses of almost 700 μSv per procedure were measured in two cases out of a sample of 33 measurements in individual clinical procedures, thus showing the risk of high exposure to the lenses of the eye when protection rules are not followed. The differences found between OSL and TLD are acceptable for the purpose and range of doses measured in the survey (authors)

  17. A medieval fallacy: the crystalline lens in the center of the eye

    Directory of Open Access Journals (Sweden)

    Leffler CT

    2016-04-01

    Full Text Available Christopher T Leffler,1 Tamer M Hadi,2 Akrithi Udupa,1 Stephen G Schwartz,3 Daniel Schwartz1 1Department of Ophthalmology, Virginia Commonwealth University, Richmond, VA, 2Graduate School of Medicine, University of Tennessee Medical Center, Knoxville, TN, 3Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA Objective: To determine whether, as most modern historians have written, ancient Greco-Roman authors believed the crystalline lens is positioned in the center of the eye. Background: Historians have written that statements about cataract couching by Celsus, or perhaps Galen of Pergamon, suggested a centrally located lens. Celsus specifically wrote that a couching needle placed intermediate between the corneal limbus and the lateral canthus enters an empty space, presumed to represent the posterior chamber. Methods: Ancient ophthalmic literature was analyzed to understand where these authors believed the crystalline lens was positioned. In order to estimate where Celsus proposed entering the eye during couching, we prospectively measured the distance from the temporal corneal limbus to the lateral canthus in 30 healthy adults. Results: Rufus of Ephesus and Galen wrote that the lens is anterior enough to contact the iris. Galen wrote that the lens equator joins other ocular structures at the corneoscleral junction. In 30 subjects, half the distance from the temporal corneal limbus to the lateral canthus was a mean of 4.5 mm (range: 3.3–5.3 mm. Descriptions of couching by Celsus and others are consistent with pars plana entry of the couching needle. Anterior angulation of the needle would permit contact of the needle with the lens. Conclusion: Ancient descriptions of anatomy and couching do not establish the microanatomic relationships of the ciliary region with any modern degree of accuracy. Nonetheless, ancient authors, such as Galen and Rufus, clearly understood that the lens is located anteriorly

  18. Dosimetric studies of the eye lens using a new dosemeter – Surveys in interventional radiology departments

    International Nuclear Information System (INIS)

    Pirchio, R.; Sánchez, H.; Domazet, W.

    2014-01-01

    During interventional radiology (IR) and cardiology (IC) procedures, medical staff can receive high doses to their eye lenses. The Retrospective Evaluation of Lens Injuries and Dose study organized in Argentina in 2010 found incipient opacity in 50% of IC physicians and 41% of IC technicians/nurses. These results, added to the recommendations of the International Commission on Radiological Protection, which lowered their former occupational equivalent dose limit for the lens, led us to assess the eye lens dose, Hp(3), during interventional procedures. To this end, a new dosemeter was designed and calibrated at the National Atomic Energy Commission of Argentina to evaluate Hp(3). Personal dose equivalent (Hp(10)), and Hp(3) were assessed for 3 months in two IC and IR departments. An Alderson phantom was used to simulate monthly exposures of five occupational staff members. Hp(3) and Hp(10) were obtained monthly for 14 occupational staff members exposed to 121 IR and IC procedures. We concluded that the annual effective dose and Hp(3) were lower than 0.3 and 10 mSv, respectively and the average cumulative Hp(3) for working life was lower than 400 and 200 mSv for physicians and technicians/scrub nurse, respectively. An occupational annual dose constraint of 0.3 mSv was calculated. - Highlights: • An eye lens dosimeters was designed at the Personal Dosimetry Laboratory of CNEA. • A successful dosimetric survey in two interventional departments was done. • The annual effective dose and the annual eye lens dose are lower than the ICRP dose thresholds. • In order to reduce doses actions should be promoted to maximize radiation protection

  19. Combination of confocal principle and aperture stop separation improves suppression of crystalline lens fluorescence in an eye model.

    Science.gov (United States)

    Klemm, Matthias; Blum, Johannes; Link, Dietmar; Hammer, Martin; Haueisen, Jens; Schweitzer, Dietrich

    2016-09-01

    Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique to detect changes in the human retina. The autofluorescence decay over time, generated by endogenous fluorophores, is measured in vivo. The strong autofluorescence of the crystalline lens, however, superimposes the intensity decay of the retina fluorescence, as the confocal principle is not able to suppress it sufficiently. Thus, the crystalline lens autofluorescence causes artifacts in the retinal fluorescence lifetimes determined from the intensity decays. Here, we present a new technique to suppress the autofluorescence of the crystalline lens by introducing an annular stop into the detection light path, which we call Schweitzer's principle. The efficacy of annular stops with an outer diameter of 7 mm and inner diameters of 1 to 5 mm are analyzed in an experimental setup using a model eye based on fluorescent dyes. Compared to the confocal principle, Schweitzer's principle with an inner diameter of 3 mm is able to reduce the simulated crystalline lens fluorescence to 4%, while 42% of the simulated retina fluorescence is preserved. Thus, we recommend the implementation of Schweitzer's principle in scanning laser ophthalmoscopes used for fundus autofluorescence measurements, especially the FLIO device, for improved image quality.

  20. Interim report of the JHPS expert committee on radiation protection of the lens of the eye (1). Overview of the lens, radiogenic cataract, and equivalent dose limit for the lens newly recommended by the ICRP

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Fujimichi, Yuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Yamauchi, Chiyo; Tsujimura, Norio; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2014-01-01

    In April 2011, the International Commission on Radiological Protection (ICRP) issued the statement on tissue reactions. This stimulated interest in many countries. The Expert Committee on Radiation Protection of the Lens of the Eye was established in the Japanese Health Physics Society, and in April 2013, started discussion about the international developments and recent studies related to the dosimetry of the lens of the eye. This committee now publishes the interim report consisting of parts I-VI. Of these, this Part I overviews the structure of the eye and lens, cataract types and the scientific evidence of its new dose threshold and equivalent dose limit newly recommended by the ICRP. (author)

  1. Effect of interface reflection in pseudophakic eyes with an additional refractive intraocular lens.

    Science.gov (United States)

    Schrecker, Jens; Zoric, Katja; Meßner, Arthur; Eppig, Timo

    2012-09-01

    To compare the surface reflections in a pseudophakic model eye with and without a monofocal additional refractive intraocular lens (add-on IOL). Department of Ophthalmology, Rudolf-Virchow-Klinikum Glauchau, Glauchau, and Experimental Ophthalmology, Saarland University, Homburg, Germany. Experimental study. The Liou and Brennan model eye was used to determine the retinal surface reflections in a pseudophakic model eye with and without an add-on IOL. The crystalline lens of the model eye was replaced by (1) a standard posterior chamber IOL (PC IOL) with a refractive power of 22.0 diopters (D) and (2) a PC IOL and an add-on IOL with refractive powers of 19.0 D and 2.5 D, respectively. To theoretically estimate the impact of the reflected images to visual impression, the signal-to-noise ratio (SNR) was calculated under 2 conditions: without and with straylight and double reflection effects. Compared with the pseudophakic model eye without an add-on IOL, the pseudophakic model eye with an add-on IOL showed no relevant differences in the SNR under both conditions. Findings indicate that implantation of monofocal add-on IOLs will not induce relevant additional disturbing glare compared with conventional pseudophakia. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  2. Real-time eye lens dose monitoring during cerebral angiography procedures

    International Nuclear Information System (INIS)

    Safari, M.J.; Wong, J.H.D.; Kadir, K.A.A.; Ng, K.H.; Thorpe, N.K.; Cutajar, D.L.; Petasecca, M.; Lerch, M.L.F.; Rosenfeld, A.B.

    2016-01-01

    To develop a real-time dose-monitoring system to measure the patient's eye lens dose during neuro-interventional procedures. Radiation dose received at left outer canthus (LOC) and left eyelid (LE) were measured using Metal-Oxide-Semiconductor Field-Effect Transistor dosimeters on 35 patients who underwent diagnostic or cerebral embolization procedures. The radiation dose received at the LOC region was significantly higher than the dose received by the LE. The maximum eye lens dose of 1492 mGy was measured at LOC region for an AVM case, followed by 907 mGy for an aneurysm case and 665 mGy for a diagnostic angiography procedure. Strong correlations (shown as R 2 ) were observed between kerma-area-product and measured eye doses (LOC: 0.78, LE: 0.68). Lateral and frontal air-kerma showed strong correlations with measured dose at LOC (AK L : 0.93, AK F : 0.78) and a weak correlation with measured dose at LE. A moderate correlation was observed between fluoroscopic time and dose measured at LE and LOC regions. The MOSkin dose-monitoring system represents a new tool enabling real-time monitoring of eye lens dose during neuro-interventional procedures. This system can provide interventionalists with information needed to adjust the clinical procedure to control the patient's dose. (orig.)

  3. Real-time eye lens dose monitoring during cerebral angiography procedures

    Energy Technology Data Exchange (ETDEWEB)

    Safari, M.J.; Wong, J.H.D.; Kadir, K.A.A.; Ng, K.H. [University of Malaya, Department of Biomedical Imaging, Faculty of Medicine, Kuala Lumpur (Malaysia); University of Malaya, University of Malaya Research Imaging Centre (UMRIC), Faculty of Medicine, Kuala Lumpur (Malaysia); Thorpe, N.K.; Cutajar, D.L.; Petasecca, M.; Lerch, M.L.F.; Rosenfeld, A.B. [University of Wollongong, Centre for Medical Radiation Physics (CMRP), Wollongong, NSW (Australia)

    2016-01-15

    To develop a real-time dose-monitoring system to measure the patient's eye lens dose during neuro-interventional procedures. Radiation dose received at left outer canthus (LOC) and left eyelid (LE) were measured using Metal-Oxide-Semiconductor Field-Effect Transistor dosimeters on 35 patients who underwent diagnostic or cerebral embolization procedures. The radiation dose received at the LOC region was significantly higher than the dose received by the LE. The maximum eye lens dose of 1492 mGy was measured at LOC region for an AVM case, followed by 907 mGy for an aneurysm case and 665 mGy for a diagnostic angiography procedure. Strong correlations (shown as R{sup 2}) were observed between kerma-area-product and measured eye doses (LOC: 0.78, LE: 0.68). Lateral and frontal air-kerma showed strong correlations with measured dose at LOC (AK{sub L}: 0.93, AK{sub F}: 0.78) and a weak correlation with measured dose at LE. A moderate correlation was observed between fluoroscopic time and dose measured at LE and LOC regions. The MOSkin dose-monitoring system represents a new tool enabling real-time monitoring of eye lens dose during neuro-interventional procedures. This system can provide interventionalists with information needed to adjust the clinical procedure to control the patient's dose. (orig.)

  4. Corneal confocal microscopy and dry eye findings in contact lens discomfort patients.

    Science.gov (United States)

    Dogan, Aysun Sanal; Gurdal, Canan; Arslan, Nese

    2018-02-01

    To evaluate the corneal confocal microscopy and dry eye findings in patients with contact lens discomfort. The study included 3 groups of participants: Contact lens wearers using silicone hydrogel soft contact lenses who are symptomatic (CLD, n=15) or asymptomatic (ACL, n=11) and non-wearers as controls (n=14). Duration of contact lens wear, Ocular Surface Disease Index (OSDI) questionnaire responses, fluorescein tear break-uptime (FBUT), and corneal confocal microscopy findings were recorded. Mean age was 25.7±8.2 years and male/female ratio was 7/33. Demographic findings were similar regarding the groups. CLD patients had a longer lens use history than ACL (median 5 vs 2 years, pCLD group than ACL or controls (pCLD group, compared to controls and ACL (pCLD group compared to controls but similar to ACL (pCLD group than the ACL (p=0.014). Patients with CLD had been wearing contact lenses for longer than those without symptoms. OSDI and FBUT scores were worse in CLD patients. In contact lens discomfort patients, there were increased dendritiform cells, indicating intensified inflammatory status of the cornea. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  5. A method to reduce patient's eye lens dose in neuro-interventional radiology procedures

    International Nuclear Information System (INIS)

    Safari, M.J.; Wong, J.H.D.; Kadir, K.A.A.; Sani, F.M.; Ng, K.H.

    2016-01-01

    Complex and prolonged neuro-interventional radiology procedures using the biplane angiography system increase the patient's risk of radiation-induced cataract. Physical collimation is the most effective way of reducing the radiation dose to the patient's eye lens, but in instances where collimation is not possible, an attenuator may be useful in protecting the eyes. In this study, an eye lens protector was designed and fabricated to reduce the radiation dose to the patients’ eye lens during neuro-interventional procedures. The eye protector was characterised before being tested on its effectiveness in a simulated aneurysm procedure on an anthropomorphic phantom. Effects on the automatic dose rate control (ADRC) and image quality are also evaluated. The eye protector reduced the radiation dose by up to 62.1% at the eye lens. The eye protector is faintly visible in the fluoroscopy images and increased the tube current by a maximum of 3.7%. It is completely invisible in the acquisition mode and does not interfere with the clinical procedure. The eye protector placed within the radiation field of view was able to reduce the radiation dose to the eye lens by direct radiation beam of the lateral x-ray tube with minimal effect on the ADRC system. - Highlights: • The eye protector can considerably reduce the patient's eye lens dose during neuro-interventional procedures. • This protector does not significantly perturb the fluoroscopy image and was completely invisible on the acquisition image due to image subtraction. • The eye protector does not significantly change the exposure parameters (kV and mAs).

  6. 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)

  7. Radiation Dose to the Lens of the Eye from Computed Tomography Scans of the Head

    Science.gov (United States)

    Januzis, Natalie Ann

    While it is well known that exposure to radiation can result in cataract formation, questions still remain about the presence of a dose threshold in radiation cataractogenesis. Since the exposure history from diagnostic CT exams is well documented in a patient's medical record, the population of patients chronically exposed to radiation from head CT exams may be an interesting area to explore for further research in this area. However, there are some challenges in estimating lens dose from head CT exams. An accurate lens dosimetry model would have to account for differences in imaging protocols, differences in head size, and the use of any dose reduction methods. The overall objective of this dissertation was to develop a comprehensive method to estimate radiation dose to the lens of the eye for patients receiving CT scans of the head. This research is comprised of a physics component, in which a lens dosimetry model was derived for head CT, and a clinical component, which involved the application of that dosimetry model to patient data. The physics component includes experiments related to the physical measurement of the radiation dose to the lens by various types of dosimeters placed within anthropomorphic phantoms. These dosimeters include high-sensitivity MOSFETs, TLDs, and radiochromic film. The six anthropomorphic phantoms used in these experiments range in age from newborn to adult. First, the lens dose from five clinically relevant head CT protocols was measured in the anthropomorphic phantoms with MOSFET dosimeters on two state-of-the-art CT scanners. The volume CT dose index (CTDIvol), which is a standard CT output index, was compared to the measured lens doses. Phantom age-specific CTDIvol-to-lens dose conversion factors were derived using linear regression analysis. Since head size can vary among individuals of the same age, a method was derived to estimate the CTDIvol-to-lens dose conversion factor using the effective head diameter. These conversion

  8. Exposition of the operator's eye lens and efficacy of radiation shielding in fluoroscopically guided interventions

    International Nuclear Information System (INIS)

    Galster, M.; Adamus, R.; Guhl, C.; Uder, M.

    2013-01-01

    Purpose: Efficacy of radiation protection tools for the eye lens dose of the radiologist in fluoroscopic interventions. Materials and Methods: A patient phantom was exposed using a fluoroscopic system. Dose measurements were made at the eye location of the radiologist using an ionization chamber. The setting followed typical fluoroscopic interventions. The reduction of scattered radiation by the equipment-mounted shielding (undercouch drapes and overcouch top) was evaluated. The ceiling-suspended lead acrylic glass screen was tested in scattered radiation generated by a slab phantom. The protective properties of different lead glass goggles and lead acrylic visors were evaluated by thermoluminescence measurements on a head phantom in the primary beam. Results: The exposition of the lens of about 110 to 550 μSv during radiologic interventions is only slightly reduced by the undercouch drapes. Applying the top in addition to the drapes reduces the lens dose by a factor of 2 for PA projections. In 25 LAO the dose is reduced by a factor between 1.2 and 5. The highest doses were measured for AP angulations furthermore the efficacy of the equipment-mounted shielding is minimal. The ceiling-suspended lead screen reduced scatter by a factor of about 30. The lead glass goggles and visors reduced the lens dose up to a factor of 8 to 10. Depending on the specific design, the tested models are less effective especially for radiation from lateral with cranial angulation of the beam. Occasionally the visors even caused an increase of dose. Conclusion: The exposition of the eye lens can be kept below the new occupational limit recommended by the ICRP if the radiation shielding equipment is used consistently. (orig.)

  9. [Exposition of the operator's eye lens and efficacy of radiation shielding in fluoroscopically guided interventions].

    Science.gov (United States)

    Galster, M; Guhl, C; Uder, M; Adamus, R

    2013-05-01

    Efficacy of radiation protection tools for the eye lens dose of the radiologist in fluoroscopic interventions. A patient phantom was exposed using a fluoroscopic system. Dose measurements were made at the eye location of the radiologist using an ionization chamber. The setting followed typical fluoroscopic interventions. The reduction of scattered radiation by the equipment-mounted shielding (undercouch drapes and overcouch top) was evaluated. The ceiling-suspended lead acrylic glass screen was tested in scattered radiation generated by a slab phantom. The protective properties of different lead glass goggles and lead acrylic visors were evaluated by thermoluminescence measurements on a head phantom in the primary beam. The exposition of the lens of about 110 to 550 μSv during radiologic interventions is only slightly reduced by the undercouch drapes. Applying the top in addition to the drapes reduces the lens dose by a factor of 2 for PA projections. In 25°LAO the dose is reduced by a factor between 1.2 and 5. The highest doses were measured for AP angulations furthermore the efficacy of the equipment-mounted shielding is minimal. The ceiling-suspended lead screen reduced scatter by a factor of about 30. The lead glass goggles and visors reduced the lens dose up to a factor of 8 to 10. Depending on the specific design, the tested models are less effective especially for radiation from lateral with cranial angulation of the beam. Occasionally the visors even caused an increase of dose. The exposition of the eye lens can be kept below the new occupational limit recommended by the ICRP if the radiation shielding equipment is used consistently. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Lens of the eye: regulatory limits, measurement, dosimetry and medical control. Technical sheets of the SFRP

    International Nuclear Information System (INIS)

    Bordy, J.M.

    2016-01-01

    As the lens of the eye are a radio-sensitive tissue which can be affected by ionizing radiations, and as epidemiological studies lead to the proposition of a revision of their exposure limit, this sheet first recalls regulatory limits and quantities to be measured. It proposes an overview of industrial and medical situations associated with an exposure risk for lens of the eye. It presents the conditions for bearing a specific individual dosimeter, and the design of dosimeters aimed at a direct measurement. It discusses the characteristics and performance of individual protection equipment, and the criterion for the choice between a direct measurement and an indirect assessment of a characteristic value of exposure for photons and for electrons. It addresses the issues of classification and monitoring for a professional medical follow-up: description of the pathological risk, elements for a medical follow-up (examinations), classification and dose monitoring

  11. First results of an eye lens dosimetry survey in an interventional cardiology department

    International Nuclear Information System (INIS)

    Ferrari, P; Mariotti, F; Campani, L; Castelluccio, D M; Pierotti, L; Pettinato, C; Golfieri, R; Marzocchi, A; De Palma, A

    2015-01-01

    The eye lens annual dose limit for exposed personnel to ionizing radiation has recently been revised by the ICRP—International Commission on Radiological Protection and the proposed new limit has been accepted by European legislation through the Council Directive 2013/59/EURATOM 2013.Among medical exposed personnel, the staff performing interventional cardiology are usually affected by relevant doses. For this reason a survey, employing dosemeters characterized in terms of H p (3), was performed in order to get the order of magnitude of the doses received by the eye lens, at least as a first guess.The survey showed that the annual dose limit can easily be reached if a proper radiation protection approach is not implemented. (practical matter)

  12. On- and off-eye spherical aberration of soft contact lenses and consequent changes of effective lens power.

    Science.gov (United States)

    Dietze, Holger H; Cox, Michael J

    2003-02-01

    Soft contact lenses produce a significant level of spherical aberration affecting their power on-eye. A simple model assuming that a thin soft contact lens aligns to the cornea predicts that these effects are similar on-eye and off-eye. The wavefront aberration for 17 eyes and 33 soft contact lenses on-eye was measured with a Shack-Hartmann wavefront sensor. The Zernike coefficients describing the on-eye spherical aberration of the soft contact lens were compared with off-eye ray-tracing results. Paraxial and effective lens power changes were determined. The model predicts the on-eye spherical aberration of soft contact lenses closely. The resulting power change for a +/- 7.00 D spherical soft contact lens is +/- 0.5 D for a 6-mm pupil diameter and +/- 0.1 D for a 3-mm pupil diameter. Power change is negligible for soft contact lenses corrected for off-eye spherical aberration. For thin soft contact lenses, the level of spherical aberration and the consequent power change is similar on-eye and off-eye. Soft contact lenses corrected for spherical aberration in air will be expected to be aberration-free on-eye and produce only negligibly small power changes. For soft contact lenses without aberration correction, for higher levels of ametropia and large pupils, the soft contact lens power should be determined with trial lenses with their power and p value similar to the prescribed lens. The benefit of soft contact lenses corrected for spherical aberration depends on the level of ocular spherical aberration.

  13. Assessment of eye lens doses in interventional radiology: a simulation in laboratory conditions

    International Nuclear Information System (INIS)

    Cemusova, Z.; Ekendahl, D.; Judas, L.

    2016-01-01

    As workers in interventional radiology belong to one of the most occupationally exposed groups, methods for sufficiently accurate quantification of their external exposure are sought. The objective of the authors' experiment was to investigate the relations between eye lens dose and H p (10), H p (3) or H p (0.07) values measured with a conventional whole-body personal thermoluminescence dosemeter (TLD). Conditions of occupational exposure during common interventional procedures were simulated in laboratory. An anthropomorphic phantom represented a physician. The TLDs were fixed to the phantom in different locations that are common for purposes of personal dosimetry. In order to monitor the dose at the eye lens level during the exposures, a special thermoluminescence eye dosemeter was fixed to the phantom's temple. Correlations between doses measured with the whole-body and the eye dosemeters were found. There are indications that personnel in interventional radiology do not need to be unconditionally equipped with additional eye dosemeters, especially if an appropriate whole-body dosimetry system has been already put into practice. (authors)

  14. Design of retinal-projection-based near-eye display with contact lens.

    Science.gov (United States)

    Wu, Yuhang; Chen, Chao Ping; Mi, Lantian; Zhang, Wenbo; Zhao, Jingxin; Lu, Yifan; Guo, Weiqian; Yu, Bing; Li, Yang; Maitlo, Nizamuddin

    2018-04-30

    We propose a design of a retinal-projection-based near-eye display for achieving ultra-large field of view, vision correction, and occlusion. Our solution is highlighted by a contact lens combo, a transparent organic light-emitting diode panel, and a twisted nematic liquid crystal panel. Its design rules are set forth in detail, followed by the results and discussion regarding the field of view, angular resolution, modulation transfer function, contrast ratio, distortion, and simulated imaging.

  15. Exposure of the lens of the eye in nuclear medicine; Strahlenexposition der Augenlinse in der Nuklearmedizin

    Energy Technology Data Exchange (ETDEWEB)

    Szermerski, B.; Bruchmann, I.; Geworski, L. [Medizinische Hochschule Hannover (Germany). Stabsstelle Strahlenschutz und Abt. Medizinische Physik

    2015-07-01

    The dose threshold for the lens of the eye for occupationally radiation-exposed personnel will be reduced from 150 mSv to 20 mSv per year. Publications addressing the expected eye lens doses of personnel in nuclear medicine are only barely known. In this work, dose rate constants for the quantity H{sub p}(3) were determined and corresponding dose estimations were calculated. Therefore dosimeters measuring H{sub p}(3) were exposed at the surface of an Alderson head phantom. The exposure of the dosimeters with frequently used radionuclides (F-18, Ga-68, Y-90, Tc-99m, In-111, I-123, I-131 and Ra-223+) was performed under varying source-dosimeter distances from 20 cm to 50 cm. The dose rate constants were determined to be 0.021 mSv.m{sup 2}/(GBq.h) for Tc-99m (10 ml syringe) and 2.161 mSv.m{sup 2}/(GBq.h) for Y-90-spheres (5 ml syringe). The other results take values between these ranges. Using the determined dose rate constants, prospective doses to the eye lens could be calculated.

  16. Recommendations to reduce extremity and eye lens doses in interventional radiology and cardiology

    International Nuclear Information System (INIS)

    Carinou, E.; Brodecki, M.; Domienik, J.; Donadille, L.; Koukorava, C.; Krim, S.; Nikodemová, D.; Ruiz-Lopez, N.; Sans-Merce, M.; Struelens, L.; Vanhavere, F.

    2011-01-01

    The main aim of the Work Package 1 (WP1) of the ORAMED project, Collaborative Project (2008–2011), supported by the European Commission within its 7th Framework Programme, was to obtain a set of standardized data on extremity and eye lens doses for staff in interventional radiology and cardiology (IR/IC) workplaces and to recommend a series of guidelines on radiation protection in order to both guarantee and optimize staff protection. Within the project, coordinated measurements were performed in 34 hospitals in 6 European countries. Furthermore, simulations of the most representative workplaces in IR and IC were performed to determine the main parameters that influence the extremity and eye lens doses. The work presented in this paper shows the recommendations that were formulated by the results obtained from both measurements and simulations. The presented guidelines are directed to operators, assistant personnel, radiation protection officers and medical physics experts. They concern radiation protection issues, such as the use of room protective equipment, as well as the positioning of the extremity and eye lens dosemeters for routine monitoring.

  17. Monte Carlo calculations on extremity and eye lens dosimetry for medical staff at interventional radiology procedures

    International Nuclear Information System (INIS)

    Carinou, E.; Ferrari, P.; Koukorava, C.; Krim, S.; Struelens, L.

    2011-01-01

    There are many factors that can influence the extremity and eye lens doses of the medical staff during interventional radiology and cardiology procedures. Numerical simulations can play an important role in evaluating extremity and eye lens doses in correlation with many different parameters. In the present study, the first results of the ORAMED (Optimisation of Radiation protection of Medical staff) simulation campaign are presented. The parameters investigated for their influence on eye lens, hand, wrist and leg doses are: tube voltage, filtration, beam projection, field size and irradiated part of the patient's body. The tube voltage ranged from 60 to 110 kVp, filtration from 3 to 6 mm Al and from 0 to 0.9 mm Cu. For all projections, the results showed that doses received by the operator decreased with increasing tube voltage and filtration. The magnitude of the influence of the tube voltage and the filtration on the doses depends on the beam projection and the irradiated part of the patient's body. Finally, the influence of the field size is significant in decreasing the doses. (authors)

  18. Effectiveness of Bismuth Shield to Reduce Eye Lens Radiation Dose Using the Photoluminescence Dosimetry in Computed Tomography

    International Nuclear Information System (INIS)

    Jung, Mi Young; Kweon, Dae Cheol; Kwon, Soo Il

    2009-01-01

    The purpose of our study was to determine the eye radiation dose when performing routine multi-detector computed tomography (MDCT). We also evaluated dose reduction and the effect on image quality of using a bismuth eye shield when performing head MDCT. Examinations were performed with a 64MDCT scanner. To compare the shielded/unshielded lens dose, the examination was performed with and without bismuth shielding in anthropomorphic phantom. To determine the average lens radiation dose, we imaged an anthropomorphic phantom into which calibrated photoluminescence glass dosimeter (PLD) were placed to measure the dose to lens. The phantom was imaged using the same protocol. Radiation doses to the lens with and without the lens shielding were measured and compared using the Student t test. In the qualitative evaluation of the MDCT scans, all were considered to be of diagnostic quality. We did not see any differences in quality between the shielded and unshielded brain. The mean radiation doses to the eye with the shield and to those without the shield were 21.54 versus 10.46 mGy, respectively. The lens shield enabled a 51.3% decrease in radiation dose to the lens. Bismuth in-plane shielding for routine eye and head MDCT decreased radiation dose to the lens without qualitative changes in image quality. The other radiosensitive superficial organs specifically must be protected with shielding.

  19. Dry Eye Treatment Based on Contact Lens Drug Delivery: A Review.

    Science.gov (United States)

    Guzman-Aranguez, Ana; Fonseca, Begoña; Carracedo, Gonzalo; Martin-Gil, Alba; Martinez-Aguila, Alejandro; Pintor, Jesús

    2016-09-01

    Dry eye disease affects a substantial segment of the word population with increasing frequency. It is a multifactorial disease of the ocular surface and tear film, which causes ocular discomfort, visual disturbances, and tear instability with potential damage to the cornea and conjunctiva. Because of its multifactorial etiology, the use of different pharmacological treatment for dry eye treatment has been proposed, which include anti-inflammatory molecules, lubricants or comfort agents, and secretagogues. However, in some cases these pharmacological approaches only relieve symptoms temporarily, and consequently, eye care professionals continue to have difficulties managing dry eye. To improve pharmacological therapy that allows a more efficient and long-term action, effective ocular drug delivery of the currently available drugs for dry eye treatment is required. Contact lenses are emerging as alternative ophthalmic drugs delivery systems that provide an increased residence time of the drug at the eye, thus leading to enhanced bioavailability and more convenient and efficacious therapy. In this article, we reviewed the different techniques used to prepare contact lens-based drug delivery systems and focused on articles that describe the delivery of compounds for dry eye treatment through contact lenses.

  20. Extremity and eye lens dosimetry for medical staff performing vertebroplasty and kyphoplasty procedures

    International Nuclear Information System (INIS)

    Struelens, L; Schoonjans, W; Vanhavere, F; Schils, F; De Smedt, K

    2013-01-01

    Measurements of doses to hands, legs and eyes are reported for operators in four different hospitals performing vertebroplasty or kyphoplasty. The results confirm that occupational doses can be high for interventional spine procedures. Extremity and eye lens doses were measured with thermoluminescent dosimeters positioned on the ring fingers, wrists, legs and near the eyes of interventional radiologists and neurosurgeons, over a period of 15 months. Doses were generally larger on the left side for all positions monitored. The median dose to the left finger was 225 μSv per procedure, although a maximum of 7.3 mSv was found. The median dose to the right finger was 118 μSv, but with an even higher maximum of 7.7 mSv. A median left eye dose of 34 μSv (maximum 836 μSv) was found, while the legs received the lowest doses with a median of 13 μSv (maximum 332 μSv) to the left leg. Annual dose to the hand assessed by the cumulated doses almost reached the annual dose limit of 500 mSv, while annual dose to the eyes exceeded the eye lens dose limit of 20 mSv yr −1 . Different x-ray systems and radiation protection measures were tested, like the use of lead gloves and glasses, tweezers, cement delivery systems and a magnetic navigation system. These measurements showed that doses can be significantly reduced. The use of lead glasses is strongly recommended for protection of the eyes. (paper)

  1. On problems of the lens of the eye radiation dose monitoring

    Directory of Open Access Journals (Sweden)

    G. N. Kaydanovsky

    2016-01-01

    Full Text Available According to results of in-depth studies, the risk of the radiation-induced cataract is higher than it was considered earlier. In April 2011, ICRP released a statement on the tissue reactions. The statement recommends that for the case of for occupational exposure in planned exposure situations, an equivalent dose for the lens of the eye should be less than 20 mSv in a year, averaged over the defined periods of 5 years, with no single year exceeding the value of 50 mSv. In this regard, the new standard IAEA № GSR Part 3 provides the dose limit of 20 mSv in a year for occupational exposure for the lens of the eye. The dosimetric data on levels of exposure for personnel in the Russian Federation is practically absent. This paper performs a preliminary evaluation of equivalent dose for the lens of the eye for personnel working in X-ray operating rooms of medical facilities in Saint Petersburg and Kazan. This group of personnel was selected because of the fact that methodic of carrying out procedures forces medical staff to be not only in the zone of scattered radiation but also in the X-ray beam. This fact significantly increases exposure doses for the personnel. It is shown that actual annual dose can exceed the new dose limit (the highest recorded value Нр(3 in 3 months of work was 8,6 mSv. We made a conclusion on the necessity of the lens of the eye dose monitoring amongst interventional specialists on conditions that new limits will be established in the Russian Federation. The Russian and foreign dosimeters for measurement of individual dose equivalent for the lens of the eye Нр(3 which have been registered in the Russian State Register of Measuring Instruments, are descrivebed in the paper.

  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. The influence of crystalline lens accommodation on post-saccadic oscillations in pupil-based eye trackers.

    Science.gov (United States)

    Nyström, Marcus; Andersson, Richard; Magnusson, Måns; Pansell, Tony; Hooge, Ignace

    2015-02-01

    It is well known that the crystalline lens (henceforth lens) can oscillate (or 'wobble') relative to the eyeball at the end of saccades. Recent research has proposed that such wobbling of the lens is a source of post-saccadic oscillations (PSOs) seen in data recorded by eye trackers that estimate gaze direction from the location of the pupil. Since the size of the lens wobbles increases with accommodative effort, one would predict a similar increase of PSO-amplitude in data recorded with a pupil based eye tracker. In four experiments, we investigated the role of lens accommodation on PSOs in a video-based eye tracker. In Experiment 1, we replicated previous results showing that PSO-amplitudes increase at near viewing distances (large vergence angles), when the lens is highly accommodated. In Experiment 2a, we manipulated the accommodative state of the lens pharmacologically using eye drops at a fixed viewing distance and found, in contrast to Experiment 1, no significant difference in PSO-amplitude related to the accommodative state of the lens. Finally, in Experiment 2b, the effect of vergence angle was investigated by comparing PSO-amplitudes at near and far while maintaining a fixed lens accommodation. Despite the pharmacologically fixed degree of accommodation, PSO-amplitudes were systematically larger in the near condition. In summary, PSOs cannot exhaustively be explained by lens wobbles. Possible confounds related to pupil size and eye-camera angle are investigated in Experiments 3 and 4, and alternative mechanisms behind PSOs are probed in the discussion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Therapeutic efficiency of sodium hyaluronate eye drops on dry eye in juvenile with myopia wearing rigid gas permeable contact lens

    Directory of Open Access Journals (Sweden)

    Bin Zhang

    2016-03-01

    Full Text Available AIM:To investigate the therapeutic efficiency of preservative-free sodium hyaluronate eye drops on dry eye in juvenile myopia wearing rigid gas permeable contact lens(RGP.METHODS:Ninety cases with dry eye related to wearing RGP in juvenile with myopia from January to May 2015 were selected. The patients aged 12.75±4.15 years old,with diopter of -3.50±1.50D as spherical equivalent and received normalized RGP. They were divided into 3 groups randomly,each group of 30 cases(60 eyes:group A used rewetting drops,1 drop each time,4 times per day; group B used preservative-free sodium hyaluronate eye drops(1g/L,1 drop each time,4 times per day; group C used rewetting drops at first, then sodium hyaluronate eye drops was used 15 minutes later.All cases had been detected and evaluated by subjective symptoms of dry eye,Schirmer I test(SⅠt,break-up time(BUTand corneal fluorescent staining,at pre-therapy and 1, 2, 4wk of post-therapy.RESULTS:The subjective symptoms of dry eye,corneal fluorescent staining and BUT of three groups had been obviously improved at 1wk after therapies than those before therapies(PP>0.05.Every index of the three groups measured at 2 and 4wk after treatments had no significant differences compared to those measured at 1wk(P>0.05.There was no significant difference on subjective symptoms,SⅠt and BUT between group A and B(P>0.05,except on corneal fluorescent staining, on which group B was superior to group A and on which the difference was significant(PPPCONCLUSION:Preservative-free sodium hyaluronate eye drops(1g/Lcan stabilize the tear film and promote the repair of corneal epithelial defects and significantly improve dry eye symptoms and signs in juvenile myopia wearing RGP,so it has certain clinical application value.

  5. Maxwell's fish-eye lens and the mirage of perfect imaging

    International Nuclear Information System (INIS)

    Merlin, R

    2011-01-01

    Recent claims that Maxwell's fish-eye is a perfect lens, capable of providing images with deep subwavelength resolution, are examined. We show that the imaging properties of a dispersionless fish-eye are very similar to those of an ideal spherical cavity. Using this correspondence, we prove that the correct solution to Maxwell equations in the fish-eye gives image sizes that are consistent with the standard diffraction limit. Perfect focusing is an optical illusion that results from placing a time-reversed source at the position of the geometrical image which, when combined with the field due to the primary (object) source, mimics the behavior of a perfect drain. Issues of causality are briefly discussed. We also demonstrate that passive outlets are not a good alternative to time-reversed sources for broadband drain-like behavior and that, even if they were, they could not do a better job than conventional optical systems at providing high resolution

  6. A scalable and deformable stylized model of the adult human eye for radiation dose assessment.

    Science.gov (United States)

    El Basha, Daniel; Furuta, Takuya; Iyer, Siva S R; Bolch, Wesley E

    2018-03-23

    With recent changes in the recommended annual limit on eye lens exposures to ionizing radiation, there is considerable interest in predictive computational dosimetry models of the human eye and its various ocular structures including the crystalline lens, ciliary body, cornea, retina, optic nerve, and central retinal artery. Computational eye models to date have been constructed as stylized models, high-resolution voxel models, and polygon mesh models. Their common feature, however, is that they are typically constructed of nominal size and of a roughly spherical shape associated with the emmetropic eye. In this study, we present a geometric eye model that is both scalable (allowing for changes in eye size) and deformable (allowing for changes in eye shape), and that is suitable for use in radiation transport studies of ocular exposures and radiation treatments of eye disease. The model allows continuous and variable changes in eye size (axial lengths from 20 to 26 mm) and eye shape (diopters from -12 to +6). As an explanatory example of its use, five models (emmetropic eyes of small, average, and large size, as well as average size eyes of -12D and +6D) were constructed and subjected to normally incident beams of monoenergetic electrons and photons, with resultant energy-dependent dose coefficients presented for both anterior and posterior eye structures. Electron dose coefficients were found to vary with changes to both eye size and shape for the posterior eye structures, while their values for the eye crystalline lens were found to be sensitive to changes in only eye size. No dependence upon eye size or eye shape was found for photon dose coefficients at energies below 2 MeV. Future applications of the model can include more extensive tabulations of dose coefficients to all ocular structures (not only the lens) as a function of eye size and shape, as well as the assessment of x-ray therapies for ocular disease for patients with non-emmetropic eyes. © 2018

  7. Simulation of airbag impact on eyes with different axial lengths after transsclerally fixated posterior chamber intraocular lens by using finite element analysis

    Directory of Open Access Journals (Sweden)

    Huang J

    2015-02-01

    Full Text Available Jane Huang,1 Eiichi Uchio,1 Satoru Goto2 1Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, 2Nihon ESI KK Technical Division, Tokyo, Japan Purpose: To determine the biomechanical response of an impacting airbag on eyes with different axial lengths with transsclerally fixated posterior chamber intraocular lens (PC IOL.Materials and methods: Simulations in a model human eye were performed with a computer using a finite element analysis program created by Nihon, ESI Group. The airbag was set to be deployed at five different velocities and to impact on eyes with three different axial lengths. These eyes were set to have transsclerally fixated PC IOL by a 10-0 polypropylene possessing a tensile force limit of 0.16 N according to the United States Pharmacopeia XXII.Results: The corneoscleral opening was observed at a speed of 40 m/second or more in all model eyes. Eyes with the longest axial length of 25.85 mm had the greatest extent of deformity at any given impact velocity. The impact force exceeded the tensile force of 10-0 polypropylene at an impact velocity of 60 m/second in all eyes, causing breakage of the suture. Conclusion: Eyes with transsclerally fixated PC IOL could rupture from airbag impact at high velocities. Eyes with long axial lengths experienced a greater deformity upon airbag impact due to a thinner eye wall. Further basic research on the biomechanical response for assessing eye injuries could help in developing a better airbag and in the further understanding of ocular traumas. Keywords: airbag, ocular trauma, computer simulation, transsclerally fixated posterior chamber intraocular lens, finite element analysis

  8. Pigment dispersion glaucoma induced by the chafing effect of intraocular lens haptics in Asian eyes.

    Science.gov (United States)

    Hong, Ying; Sun, Yan-Xiu; Qi, Hong; Zhou, Ji-Chao; Hao, Yan-Sheng

    2013-03-01

    To study the possible mechanism and treatment for pigment dispersion glaucoma (PDG) caused by single-piece acrylic (SPA) intraocular lens (IOL) ciliary sulcus fixation in Asian eyes. Patients referred for PDG caused by SPA IOL ciliary sulcus fixation to our hospital from April 2005 to June 2011 were included. The patients' general information, IOL type, interval between initial surgery and PDG occurrence, examination findings, antiglaucoma medicine regimen and surgical interventions were recorded. In total, six eyes from five Chinese patients were included in this study. The intraocular pressure (IOP) increased 19-30 days after cataract surgery and was not satisfactorily controlled with antiglaucoma medication. Dense pigmentation was deposited on the IOLs and on the anterior chamber angle. IOL haptic chafing was noted on the rear iris surface. IOL repositioning in the capsular bag was performed in three eyes and was combined with trabeculectomy in two eyes with progressive glaucoma. An IOL exchange with three-piece IOL ciliary sulcus fixation was performed in the other three eyes. Scanning electron microscopy of the explanted IOLs demonstrated a rough edge on the IOL haptics. SPA IOLs were not suitable for ciliary sulcus fixation. The chafing effect of the IOL haptics on the posterior iris pigment epithelium could induce PDG in Asian eyes. IOLs should be positioned in the capsular bag or a three-piece IOL should be used instead.

  9. Eye lens radiation exposure and repeated head CT scans: A problem to keep in mind

    International Nuclear Information System (INIS)

    Michel, Morgane; Jacob, Sophie; Roger, Gilles; Pelosse, Béatrice; Laurier, Dominique; Le Pointe, Hubert Ducou; Bernier, Marie-Odile

    2012-01-01

    Objectives: The deterministic character of radiation-induced cataract is being called into question, raising the possibility of a risk in patients, especially children, exposed to ionizing radiation in case of repeated head CT-scans. This study aims to estimate the eye lens doses of a pediatric population exposed to repeated head CTs and to assess the feasibility of an epidemiological study. Methods: Children treated for a cholesteatoma, who had had at least one CT-scan of the middle ear before their tenth birthday, were included. Radiation exposure has been assessed from medical records and telephone interviews. Results: Out of the 39 subjects contacted, 32 accepted to participate. A total of 76 CT-scans were retrieved from medical records. At the time of the interview (mean age: 16 years), the mean number of CT per child was 3. Cumulative mean effective and eye lens doses were 1.7 mSv and 168 mGy, respectively. Conclusion: A relatively high lens radiation dose was observed in children exposed to repeated CT-scans. Due to that exposure and despite the difficulties met when trying to reach patients’ families, a large scale epidemiological study should be performed in order to assess the risk of radiation-induced cataracts associated with repeated head CT.

  10. Exposure of the thyroid and lens of the eye from scatter during mammography

    International Nuclear Information System (INIS)

    Ritenour, E.R.; Plott, C.M.; Ahrens, C.R.

    1987-01-01

    Exposure of the thyroid and lens of the eye of the patient during mammography was evaluated in a survey of mammographic units in the Denver area. Ion chambers calibrated for the mammographic energy range were used to measure exposure at standard distances superior and dorsal to Solid Water (R) phantoms placed in the compression device. Technique factors as used clinically for craniocaudal views were selected. A bimodal distribution of exposure values was found. Several units produced thyroid entrance surface exposures below 5 mR while the rest produced exposures exceeding 20 mR. Exposures to the lens of the eye were typically half the magnitude of the thyroid exposures. A table of results is presented in this paper along with evaluation of breast entrance exposure for each unit. The thyroid and lens exposures were found to be due to scatter from the patient's breast and the image receptor/compression device assembly of some of the units. The exposure in the high exposure group may be substantially reduced by the addition of a simple aluminum shield to the collimator or image receptor assembly

  11. A scalable and deformable stylized model of the adult human eye for radiation dose assessment

    Science.gov (United States)

    El Basha, Daniel; Furuta, Takuya; Iyer, Siva S. R.; Bolch, Wesley E.

    2018-05-01

    With recent changes in the recommended annual limit on eye lens exposures to ionizing radiation, there is considerable interest in predictive computational dosimetry models of the human eye and its various ocular structures including the crystalline lens, ciliary body, cornea, retina, optic nerve, and central retinal artery. Computational eye models to date have been constructed as stylized models, high-resolution voxel models, and polygon mesh models. Their common feature, however, is that they are typically constructed of nominal size and of a roughly spherical shape associated with the emmetropic eye. In this study, we present a geometric eye model that is both scalable (allowing for changes in eye size) and deformable (allowing for changes in eye shape), and that is suitable for use in radiation transport studies of ocular exposures and radiation treatments of eye disease. The model allows continuous and variable changes in eye size (axial lengths from 20 to 26 mm) and eye shape (diopters from  ‑12 to  +6). As an explanatory example of its use, five models (emmetropic eyes of small, average, and large size, as well as average size eyes of  ‑12D and  +6D) were constructed and subjected to normally incident beams of monoenergetic electrons and photons, with resultant energy-dependent dose coefficients presented for both anterior and posterior eye structures. Electron dose coefficients were found to vary with changes to both eye size and shape for the posterior eye structures, while their values for the crystalline lens were found to be sensitive to changes in only eye size. No dependence upon eye size or eye shape was found for photon dose coefficients at energies below 2 MeV. Future applications of the model can include more extensive tabulations of dose coefficients to all ocular structures (not only the lens) as a function of eye size and shape, as well as the assessment of x-ray therapies for ocular disease for patients with non

  12. Acanthamoeba keratitis in a non-contact lens wearer with human immunodeficiency virus

    DEFF Research Database (Denmark)

    Hansen, Birgitte Rønde; Kronborg, Gitte

    2003-01-01

    Acanthamoeba keratitis is potentially blinding and often associated with contact lens wearing. A human immunodeficiency virus (HIV)-positive patient, a non-contact lens wearer, presented with keratitis. She experienced a protracted course of disease, characterized by exacerbations and remissions......, and was treated with various topical antibiotics and steroids. 13 months after symptom onset the eye was removed owing to serious scarring of cornea and unbearable pain. Microbiological and histopathological examination of the cornea showed Acanthamoeba. In non-contact lens wearers suffering from Acanthamoeba...... keratitis the diagnosis is delayed, pathognomonic features are often not seen and visual outcome is usually poor. There is no known relation between HIV infection and Acanthamoeba keratitis....

  13. Optical transmission and laser ablation of pathologically changed eye lens capsule

    Energy Technology Data Exchange (ETDEWEB)

    Gamidov, A A; Bolshunov, A V [Research Institute of Eye Diseases, Russian Academy of Medical Sciences, Moscow (Russian Federation); Yuzhakov, A V; Shcherbakov, E M; Baum, O I; Sobol, E N [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation)

    2015-02-28

    Optical transmission and ablation mechanisms in the secondary cataract films under the impact of 1.06-mm laser radiation are studied. The comparison of incident and transmitted (paraxial) radiation power at different values of the power density is carried out for two types of the eye lens capsule tissue (hard and soft) possessing different optical and mechanical properties. It is found that the effective attenuation coefficient for soft films is almost five times as large as that for the hard ones. The obtained measurement data on the transparency variation in the process of laser action allow the temperature evaluation and the determination of dominant mechanism of laser ablation, as well as the development of recommendations, providing the prevention or reduction of possible side effects. The obtained results can be used to optimise the regimes of laser impact in the process of the opacified lens capsule removal.

  14. Diquafosol Ophthalmic Solution Increases Pre- and Postlens Tear Film During Contact Lens Wear in Rabbit Eyes.

    Science.gov (United States)

    Nagahara, Yukiko; Koh, Shizuka; Oshita, Yoshihiro; Nagano, Takashi; Mano, Hidetoshi; Nishida, Kohji; Watanabe, Hitoshi

    2017-11-01

    To investigate the behavior of prelens tear film (PLTF) and postlens tear film (PoLTF) after the instillation of diquafosol using an experimental rabbit model of eyes with contact lens. Cross-sectional, anterior segment optical coherence tomographic images of the inferior midperipheral cornea were obtained at baseline and at 5, 15, 30, 60, 90, and 120 min after the instillation of 3% diquafosol ophthalmic solution in 10 Japanese white rabbits wearing contact lenses. From the obtained images, the areas of the PLTF and PoLTF were calculated. Both artificial tear solution and 0.1% sodium hyaluronate ophthalmic solution were used for comparison. Significant fluid accumulation in both the PLTF and PoLTF was observed after diquafosol instillation, whereas no fluid accumulation was visible after the instillation of artificial tear or sodium hyaluronate. The increase in PLTF area after diquafosol instillation was significantly higher (Pophthalmic solution increases PLTF and PoLTF in rabbit eyes with contact lenses. Diquafosol has potential as a treatment option for contact lens-related dry eye.

  15. Temperature elevation in the eye of anatomically based human head models for plane-wave exposures

    International Nuclear Information System (INIS)

    Hirata, A; Watanabe, S; Fujiwara, O; Kojima, M; Sasaki, K; Shiozawa, T

    2007-01-01

    This study investigated the temperature elevation in the eye of anatomically based human head models for plane-wave exposures. The finite-difference time-domain method is used for analyzing electromagnetic absorption and temperature elevation. The eyes in the anatomic models have average dimensions and weight. Computational results show that the ratio of maximum temperature in the lens to the eye-average SAR (named 'heating factor for the lens') is almost uniform (0.112-0.147 deg. C kg W -1 ) in the frequency region below 3 GHz. Above 3 GHz, this ratio increases gradually with an increase of frequency, which is attributed to the penetration depth of an electromagnetic wave. Particular attention is paid to the difference in the heating factor for the lens between this study and earlier works. Considering causes clarified in this study, compensated heating factors in all these studies are found to be in good agreement

  16. EVALUATION OF EYE LENS DOSE TO WORKERS IN THE STEAM GENERATOR AT THE KOREAN OPTIMIZED POWER REACTOR 1000.

    Science.gov (United States)

    Maeng, Sung Jun; Kim, Jinhwan; Cho, Gyuseong

    2018-03-15

    ICRP (2011) revised the dose limit to the eye lens to 20 mSv/y based on a recent epidemiological study of radiation-induced cataracts. Maintenance of steam generators at nuclear power plants is one of the highest radiation-associated tasks within a non-uniform radiation field. This study aims to evaluate eye lens doses in the steam generators of the Korean OPR1000 design. The source term was characterized based on the CRUD-specific activity, and both the eye lens dose and organ dose were simulated using MCNP6 combined with an ICRP voxel phantom and a mesh phantom, respectively. The eye lens dose was determined to be 5.39E-02-9.43E-02 Sv/h, with a negligible effect by beta particles. As the effective dose was found to be 0.81-1.21 times the lens equivalent dose depending on the phantom angles, the former can be used to estimate the lens dose in the SG of the OPR1000 for radiation monitoring purposes.

  17. Does reproduction accelerate the growth of eye lens mass in female voles?

    Czech Academy of Sciences Publication Activity Database

    Jánová, Eva; Havelková, Dana; Tkadlec, Emil

    2007-01-01

    Roč. 137, č. 1 (2007), s. 85-88 ISSN 0777-6276 R&D Projects: GA ČR GA206/04/2003; GA ČR(CZ) GD524/05/H536 Institutional research plan: CEZ:AV0Z60930519 Keywords : age estimation * eye lens mass * reproduction Subject RIV: EH - Ecology, Behaviour Impact factor: 0.433, year: 2007 http://www.naturalsciences.be/institute/associations/rbzs_website/bjz/back/pdf/BJZ%20137(1)/Volume%20137(1),%20pp.%2085-88.pdf

  18. [Eye lens radiation exposure during ureteroscopy with and without a face protection shield: Investigations on a phantom model].

    Science.gov (United States)

    Zöller, G; Figel, M; Denk, J; Schulz, K; Sabo, A

    2016-03-01

    Eye lens radiation exposure during radiologically-guided endoscopic procedures may result in radiation-induced cataracts; therefore, we investigated the ocular radiation exposure during ureteroscopy on a phantom model. Using an Alderson phantom model and eye lens dosimeters, we measured the ocular radiation exposure depending on the number of X-ray images and on the duration of fluoroscopic imaging. The measurements were done with and without using a face protection shield. We could demonstrate that a significant ocular radiation exposure can occur, depending on the number of X-ray images and on the duration time of fluoroscopy. Eye lens doses up to 0.025 mSv were recorded even using modern digital X-ray systems. Using face protection shields this ocular radiation exposure can be reduced to a minimum. The International Commission on Radiological Protection (ICRP) recommendations of a mean eye lens dosage of 20 mSv/year may be exceeded during repeated ureteroscopy by a high volume surgeon. Using a face protection shield, the eye lens dose during ureteroscopy could be reduced to a minimum in a phantom model. Further investigations will show whether these results can be transferred to real life ureteroscopic procedures.

  19. Estimation of eye lens dose during brain scans using Gafchromic XR-QA2 film in various multidetector CT scanners

    International Nuclear Information System (INIS)

    Akhilesh, Philomina; Jamhale, Shramika H.; Sharma, S.D.; Kumar, Rajesh; Datta, D.; Kulkarni, Arti R.

    2017-01-01

    The purpose of this study was to estimate eye lens dose during brain scans in 16-, 64-, 128- and 256-slice multidetector computed tomography (CT) scanners in helical acquisition mode and to test the feasibility of using radiochromic film as eye lens dosemeter during CT scanning. Eye lens dose measurements were performed using Gafchromic XR-QA2 film on a polystyrene head phantom designed with outer dimensions equivalent to the head size of a reference Indian man. The response accuracy of XR-QA2 film was validated by using thermoluminescence dosemeters. The eye lens dose measured using XR-QA2 film on head phantom for plain brain scanning in helical mode ranged from 43.8 to 45.8 mGy. The XR-QA2 film measured dose values were in agreement with TLD measured dose values within a maximum variation of 8.9%. The good correlation between the two data sets confirms the viability of using XR-QA2 film for eye lens dosimetry. (authors)

  20. Changes induced to eye lens membrane characterization after treatments with beta radiation from Sr90

    International Nuclear Information System (INIS)

    El-Refaei, F.M.; Morris, M.; Gamal, M.M.; Fadel, M.A.

    1994-12-01

    The effect of β-particles on Na + and k + content, Na + -k + ATPase and histopathological changes of cell membrane were studied in the present work. One of the two eyes of New Zealand rabbits from both sexes were irradiated with β-particles from Sr 90 source to 10, 20, 40 and 60 Gy. The effect of β-particles on lens membrane after 3 months of exposure to 20 and 60 Gy was also studied. The results indicated that the treated and untreated eyes suffered pronounced injuries which deduced from the distribution of ATPase in comparison with the normal control which showed a decrease (reached 52%). As well as uncontrolled transport of the Na + and k + through the membrane and injuries appeared in the histopathological studies. (author). 12 refs, 15 figs, 4 tabs

  1. An overview of equivalent doses in eye lens of occupational radiation workers in medical, industrial and nuclear areas

    International Nuclear Information System (INIS)

    Lima, A.R.; Silva, F.C.A. da; Hunt, J.G.

    2013-01-01

    Some epidemiological evidences were recently reviewed by the ICRP and it was suggested that, for the eye lens, the absorbed dose threshold for induction of late detriments is about 0.5 Gy. On this basis, on 2011, the ICRP has recommended changes to the occupational dose limit in planned exposure situations, reducing the eye lens dose equivalent limit of 150 mSv to 20 mSv per year, on average, during the period of 5 years, with exposure not exceeding 50 mSv in a single year. Following the ICRP recommendation, the Brazilian Commission of Nuclear Energy (CNEN) adopted immediately the new limit to the eyes lens. This study aimed to show an overview about the doses in eye lens of occupational radiation workers in situations of planned exposures in the medical, industrial and nuclear areas, emphasizing the greatest radiological risks applications. It was observed that there are some limitations, such as example, to use individual monitor calibrated on Hp(3), to assess the equivalent dose in the eye lens. This limitation obstructs some experimental studies and monitoring of the levels of radiation received in the eye lens of radiation workers. Recent studies have showed that the lenses of eyes monitoring of workers, mainly in the planned exposure, must be follow-up. However, such researches were obtained only in medical exposures, mainly in interventional medicine procedures. Studies with planned exposure on nuclear and industrial areas are really needed and will be very important due to the new recommended by ICRP dose limits. (author)

  2. Analysis of eye lens-specific genes in congenital hereditary cataracts and microphthalmia of the miniature schnauzer dog.

    Science.gov (United States)

    Zhang, R L; Samuelson, D A; Zhang, Z G; Reddy, V N; Shastry, B S

    1991-08-01

    The congenital hereditary cataracts and microphthalmia in the miniature schnauzer dog are inherited by an autosomal recessive mode. To understand the genetic basis of these diseases, the authors purified and analyzed leukocyte deoxyribonucleic acid (DNA) from affected and normal animals using a candidate gene approach. Because the genes that encode the lens-specific proteins, specifically, alpha, beta, and gamma crystallins and the membrane protein (MP26), are known to maintain the structure and function of the lens, the authors used complimentary DNA (cDNA) fragments that corresponded to the above genes to search for the mutations at their loci in the affected animals. They found no evidence of the gene deletion and rearrangement in any of the five loci. In addition, the hybridizable sequences of the dog DNA to the specific probes for the human chromosome 4 and 18 loci, which are reported to be involved in the abnormality of the human eye, seem to be unaffected. These data support the notion that the hereditary cataracts and microphthalmia in the dog may be associated with genes other than those reported for several animal systems.

  3. SU-E-J-11: Measurement of Eye Lens Dose for Varian On-Board Imaging with Different CBCT Acquisition Techniques

    International Nuclear Information System (INIS)

    Deshpande, S; Dhote, D; Kumar, R; Thakur, K

    2015-01-01

    Purpose: To measure actual patient eye lens dose for different cone beam computed tomography (CBCT) acquisition protocol of Varian’s On Board Imagining (OBI) system using Optically Stimulated Luminescence (OSL) dosimeter and study the eye lens dose with patient geometry and distance of isocenter to the eye lens Methods: OSL dosimeter was used to measure eye lens dose of patient. OSL dosimeter was placed on patient forehead center during CBCT image acquisition to measure eye lens dose. For three different cone beam acquisition protocol (standard dose head, low dose head and high quality head) of Varian On-Board Imaging, eye lens doses were measured. Measured doses were correlated with patient geometry and distance between isocenter to eye lens. Results: Measured eye lens dose for standard dose head was in the range of 1.8 mGy to 3.2 mGy, for high quality head protocol dose was in range of 4.5mGy to 9.9 mGy whereas for low dose head was in the range of 0.3mGy to 0.7mGy. Dose to eye lens is depends upon position of isocenter. For posterioraly located tumor eye lens dose is less. Conclusion: From measured doses it can be concluded that by proper selection of imagining protocol and frequency of imaging, it is possible to restrict the eye lens dose below the new limit set by ICRP. However, undoubted advantages of imaging system should be counter balanced by careful consideration of imaging protocol especially for very intense imaging sequences for Adoptive Radiotherapy or IMRT

  4. Design of an in-vivo microscope to characterize cataracts in human eyes

    Science.gov (United States)

    Feng, Chen; Ahmad, Anees

    1996-11-01

    The design of a compact contact microscope, which can be used in-vivo to study the cataracts in human eyes is presented. This microscope has the capability to evaluate the changes in the optical density within the eye lens itself, and thus enabling an examiner to ascertain the progression of a cataractous change or at least the optical changes associated with cataractous development. The microscope has a variable focal length so it can be focused at any depth through the entire thickness of the eye lens. A separate small objective lens is spring loaded against the cornea (like a tonometer tip) so that the natural eye movements can occur safely during the examination. The distance between the objective lens and rest of the optics is variable to accommodate the movements of the eye due to pulse or breathing without affecting the image quality of the instrument. The layer by layer images can be captured on a CCD camera and stored in the computer. The reconstruction software can quantitatively display the characteristics of the cataracts, such as the location, size, and density. The optical design and performance results for the microscope are presented. The optomechanical design features of the microscope are also discussed.

  5. Droplets on posterior surface of intraocular lens in silicone oil filled eye.

    Directory of Open Access Journals (Sweden)

    Sharma Y

    2003-01-01

    Full Text Available Silicone oil adherence to silicone IOLs after silicone oil removal is a known complication in pseudophakic patients. Droplet removal is difficult and may require IOL exchange. We describe two cases in which silicone oil droplets were observed early in the postoperative period in PMMA pseudophakic eyes and disappeared during silicone oil-fluid exchange--a phenomenon that has not been reported earlier in human PMMA pseudophakic eyes.

  6. Eye lens dosimetry in interventional cardiology: Results of staff dose measurements and link to patient dose levels

    International Nuclear Information System (INIS)

    Antic, V.; Ciraj-Bjelac, O.; Rehani, M.; Aleksandric, S.; Arandjic, D.; Ostojic, M.

    2013-01-01

    Workers involved in interventional cardiology procedures receive high eye lens dose if protection is not used. Currently, there is no suitable method for routine use for the measurement of eye dose. Since most angiography machines are equipped with suitable patient dosemeters, deriving factors linking staff eye doses to the patient doses can be helpful. In this study the patient kerma-area product, cumulative dose at an interventional reference point and eye dose in terms of Hp(3) of the cardiologists, nurses and radiographers for interventional cardiology procedures have been measured. Correlations between the patient dose and the staff eye dose were obtained. The mean eye dose was 121 mSv for the first operator, 33 mSv for the second operator/nurse and 12 mSv for radiographer. Normalised eye lens doses per unit kerma-area product were 0.94 mSv Gy -1 cm -2 for the first operator, 0.33 mSv Gy -1 cm -2 for the second operator/nurse and 0.16 mSv Gy -1 cm -2 for radiographers. Statistical analysis indicated that there is a weak but significant (p < 0.01) correlation between the eye dose and the kerma-area product for all three staff categories. These values are based on a local practice and may provide useful reference for other studies for validation and for wider utilisation in assessing the eye dose using patient dose values. (authors)

  7. Comparing the Zeiss Callisto Eye and the Alcon Verion Image Guided System Toric Lens Alignment Technologies.

    Science.gov (United States)

    Hura, Arjan S; Osher, Robert H

    2017-07-01

    To compare the alignment meridian generated by the Zeiss Callisto Eye (Carl Zeiss AG, Dublin, CA) and the Alcon Verion Image Guided System (Alcon Laboratories, Inc., Fort Worth, TX). In this retrospective comparative evaluation of technology, intraoperative images were captured at different steps in the same surgery, allowing the comparison of the guidance lines generated by the Verion system to the parallel guidance lines generated by the Callisto Eye system. Measurements of each hemi-meridian were quantified using Adobe Photoshop 2015 CC software (Adobe Systems, San Jose, CA). The numbers of degrees separating these alignment meridians were calculated, entered into a database, and analyzed. The authors found that of 98 captured images of 16 eyes, the two technologies were identical in 0 eyes (θ 1 = θ 2 = 0), similar by 3° in 52 (53%) captured images (θ 1 ≠ θ 2 ≠ 0), and different by at least 3° in 46 (47%) captured images (θ 1 ≠ θ 2 ≠ 0). The target meridians were superimposed, the target lines were minimally separated, and the target lines were dissimilar. It was noted that some intraoperative variation occurred from measurement to measurement. Within the small group of 16 cases of routine toric lens implantation in this study, the absolute average number of degrees of misalignment between the Verion and Callisto Eye systems was 3.355 for θ 1 and 3.838 for θ 2 . On average, the intraoperative variation termed "drift" was noted to be 3.963° for θ 1 , and 4.557° for θ 2 . The authors found that small deviations were frequent when comparing two sophisticated technologies. Although deviations greater than 3° occurred in less than 47% of captured images from 16 eyes, smaller but significant variations of less than 3° occurred in 53% of captured images from 16 eyes. It was rare to identify a large deviation. However, the authors identified "drift" in the same eye when measurements were taken at different times. The results indicate that the two

  8. Evaluation of the True Wavefront Aberrations in Eyes Implanted With a Rotationally Asymmetric Multifocal Intraocular Lens.

    Science.gov (United States)

    Akondi, Vyas; Pérez-Merino, Pablo; Martinez-Enriquez, Eduardo; Dorronsoro, Carlos; Alejandre, Nicolás; Jiménez-Alfaro, Ignacio; Marcos, Susana

    2017-04-01

    Standard evaluation of aberrations from wavefront slope measurements in patients implanted with a rotationally asymmetric multifocal intraocular lens (IOL), the Lentis Mplus (Oculentis GmbH, Berlin, Germany), results in large magnitude primary vertical coma, which is attributed to the intrinsic IOL design. The new proposed method analyzes aberrometry data, allowing disentangling the IOL power pupillary distribution from the true higher order aberrations of the eye. The new method of wavefront reconstruction uses retinal spots obtained at both the near and far foci. The method was tested using ray tracing optical simulations in a computer eye model virtually implanted with the Lentis Mplus IOL, with a generic cornea or with anterior segment geometry obtained from custom quantitative spectral-domain optical coherence tomography in a real patient. The method was applied to laser ray tracing aberrometry data at near and far fixation obtained in a patient implanted with the Lentis Mplus IOL. Higher order aberrations evaluated from simulated and real retinal spot diagrams following the new reconstruction approach matched the nominal aberrations (approximately 98%). Previously reported primary vertical coma in patients implanted with this IOL lost significance with the application of the proposed reconstruction. Custom analysis of ray tracing-based retinal spot diagrams allowed decoupling of the true higher order aberrations of the patient's eye from the power pupillary distribution of a rotationally asymmetric multifocal IOL, therefore providing the appropriate phase map to accurately evaluate through-focus optical quality. [J Refract Surg. 2017;33(4):257-265.]. Copyright 2017, SLACK Incorporated.

  9. Multifocal Intraocular Lens Results in Correcting Presbyopia in Eyes After Radial Keratotomy.

    Science.gov (United States)

    Kim, Kyeong Hwan; Seok, Kyung-Won; Kim, Wan Soo

    2017-11-01

    To report results of multifocal intraocular lens (IOL) implantation in 2 patients with refractive error and presbyopia after previous radial keratotomy (RK). A refractive multifocal IOL with rotational asymmetry (LS313-MF30; Oculentis, Berlin, Germany) was implanted. The first patient was a 60-year-old man with myopia who underwent unilateral RK 20 years before. His uncorrected distance visual acuity (UDVA) was 20/400, and his distance corrected near vision was J9 in both eyes. Six months after bilateral surgery, his binocular UDVA and uncorrected near visual acuity (UNVA) improved to 20/20 and J1, respectively, although he experienced diurnal fluctuation. The second patient was a 55-year-old woman with hyperopia who underwent bilateral RK 18 years before. Uncorrected distance visual acuity was 20/25 in both eyes, but UNVA was between J9 and J10. Three months after unilateral surgery, UDVA and UNVA of the postsurgical eye improved to 20/20 and J1, respectively. Neither patient reported any significant photic phenomena, and both were satisfied with the results of treatment. The desirable clinical outcomes and levels of satisfaction expressed by these patients indicate that surgery using this particular multifocal IOL may benefit presbyopic patients with previous RK.

  10. Implantation of a double iris-claw intraocular lens in an aphakic nanophthalmic eye

    Directory of Open Access Journals (Sweden)

    Filiz Avsin Ozdemir Sarioglu

    2017-01-01

    Full Text Available A 55-year-old female with an aphakic nanophthalmic eye underwent a secondary intraocular lens implantation (IOL with double Artisan aphakia iris claw IOLs (ICIOLs and was evaluated in this research. The patient's preoperative best-corrected visual acuity (BCVA of the right eye was 0.4 (0.4 logMAR (with + 21.00 D, postoperative 1st and 3rd month, 1st year, and 3 years BCVAs were 0.4 (0.4 logMAR. The intraocular pressure was 15 mmHg preoperatively, and 14, 12, 12, and 15 mmHg postoperatively at 1st and 3rd month, 1st year, and 3 years, respectively. The preoperative endothelial cell density (ECD was 2372 cells/mm2, and postoperative ECDs were 2352, 2391, 2246, and 2240 cells/mm2 at 1st and 3rd months, at 1st year, and 3 years respectively. In aphakic nanophthalmic eyes with inadequate capsular support, which require high IOL dioptry, the implantation of double ICIOLs (one in front of the iris and the other behind the iris seems to be safe and provides good visual rehabilitation.

  11. Influence of aspheric intraocular lens on frequency doubling technology and contrast sensitivity: a fellow eye study

    Directory of Open Access Journals (Sweden)

    Rodrigo França de Espíndola

    2014-12-01

    Full Text Available Purpose: To evaluate whether implantation of an aspheric intraocular lens (IOL results in reduced ocular aberrations and improved contrast sensitivity after cataract surgery and, therefore, changes on frequency-doubling technology (FDT testing. Methods: The present prospective clinical study enrolled 25 patients with bilateral cataract (50 eyes, who randomly received either an aspheric (Akreos AO or a spherical (Akreos Fit IOL in one eye and the other IOL in the second eye. Assessment 12 months postoperatively included photopic and mesopic contrast sensitivity testing. Higher-order aberrations (HOAs were computed. FDT testing was divided into four areas to evaluate the variation of the values at different points. The median values of the local pattern thresholds (median area contrast sensitivity [MACS] obtained with that division were calculated. Results: The Akreos AO group obtained statistically significantly lower values of HOAs and spherical aberration compared with the Akreos Fit group. There was a statistically significant between-group difference in contrast sensitivity under mesopic conditions at all spatial frequencies. No statistically significant differences were observed in mean deviation and pattern standard deviation. The aspheric IOL exhibited higher MACS in all areas, although a statistically significant difference was reached only in the 20-degree field area (P=0.043. Conclusion: Aspheric IOLs significantly reduced spherical aberration and HOAs, improving mesopic contrast sensitivity. Although there was a trend toward slightly improved FDT in the aspheric IOL group, it was not statistically significant.

  12. Modelling human eye under blast loading.

    Science.gov (United States)

    Esposito, L; Clemente, C; Bonora, N; Rossi, T

    2015-01-01

    Primary blast injury (PBI) is the general term that refers to injuries resulting from the mere interaction of a blast wave with the body. Although few instances of primary ocular blast injury, without a concomitant secondary blast injury from debris, are documented, some experimental studies demonstrate its occurrence. In order to investigate PBI to the eye, a finite element model of the human eye using simple constitutive models was developed. The material parameters were calibrated by a multi-objective optimisation performed on available eye impact test data. The behaviour of the human eye and the dynamics of mechanisms occurring under PBI loading conditions were modelled. For the generation of the blast waves, different combinations of explosive (trinitrotoluene) mass charge and distance from the eye were analysed. An interpretation of the resulting pressure, based on the propagation and reflection of the waves inside the eye bulb and orbit, is proposed. The peculiar geometry of the bony orbit (similar to a frustum cone) can induce a resonance cavity effect and generate a pressure standing wave potentially hurtful for eye tissues.

  13. Interim report of the JHPS expert committee on radiation protection of the lens of the eye (2). The dosimetry method for the lens of the eye of workers in Japan

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Fujimichi, Yuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Yamauchi, Chiyo; Tsujimura, Norio; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2014-01-01

    A brief review is given of the history and methodology of external dosimetry for the lens of the eye. Under the 1989 revision to domestic radiological protection regulations, the concept on the effective dose equivalent and the dose limit to the lens of the eye (150 mSv/y) both introduced in the ICRP 1977 recommendations has changed nationwide the external monitoring methodology in non-uniform exposure situations to the trunk of a radiological worker. In such situations, which are often created by the presence of a protective apron, the worker is required to use at least two personal dosemeters, one worn on the trunk under the apron and the other, typically, at the collar over the apron. The latter dosemeter serves the dual purpose of providing the dose profile across the trunk for improved effective dose equivalent assessment and of estimating the dose to lens of the eye. The greater or appropriate value between H p (10) and H p (0.07), given by the dosemeter, is generally used as a surrogate of H p (3) for recording the dose to the lens of the eye. The above-mentioned methodology was continued in the latest 2001 revision to the relevant regulations. (author)

  14. A wide-angle gradient index optical model of the crystalline lens and eye of the octopus.

    Science.gov (United States)

    Jagger, W S; Sands, P J

    1999-08-01

    Cephalopods and fish have had no common ancestor since the Cambrian, and their eyes are a classic example of convergent evolution. The octopus has no cornea, and immerson renders the trout cornea optically ineffective. As a result, the nearly spherical lens is responsible for all refraction in these eyes. In spite of the fact that the octopus lens consists of two joined parts, while the trout lens consists of one part, we show here that their optical properties are very similar. An index gradient bends rays within these lenses, adding power and correcting spherical aberration. High spherical symmetry in both lenses strongly reduces other monochromatic aberrations and yields a wide field of vision, advantageous in attack and evasion. The octopus Mattheissen's ratio, 2.83, an inverse measure of light-gathering power, lies above the trout value of 2.38 but within the range of values reported for fish. Strong uncorrected longitudinal chromatic aberration is nearly identical in both animals as a result of similar lens protein optical properties, and will limit resolution. We discuss how animal lifestyle requirements and lens material properties influence the design of these eyes.

  15. Navigation system for a mobile robot with a visual sensor using a fish-eye lens

    Science.gov (United States)

    Kurata, Junichi; Grattan, Kenneth T. V.; Uchiyama, Hironobu

    1998-02-01

    Various position sensing and navigation systems have been proposed for the autonomous control of mobile robots. Some of these systems have been installed with an omnidirectional visual sensor system that proved very useful in obtaining information on the environment around the mobile robot for position reckoning. In this article, this type of navigation system is discussed. The sensor is composed of one TV camera with a fish-eye lens, using a reference target on a ceiling and hybrid image processing circuits. The position of the robot, with respect to the floor, is calculated by integrating the information obtained from a visual sensor and a gyroscope mounted in the mobile robot, and the use of a simple algorithm based on PTP control for guidance is discussed. An experimental trial showed that the proposed system was both valid and useful for the navigation of an indoor vehicle.

  16. Estimation of deep, eye lens and skin doses for high energy electron beams for dosimetry and protection purpose

    International Nuclear Information System (INIS)

    Reena Kumari; Rakesh, R.B.

    2018-01-01

    In the radiological protection especially for individual as well as area monitoring, it is generally considered that beta sources deposit skin and eye lens doses only as they do not have enough energy for depositing doses at 10 mm depth. Also, the skin and eye lens doses differ substantially due to attenuation of beta particles at 0.07 mm (skin) and 3 mm (eye lens) depths and the surface doses are always greater than eye lens doses even for the highest energy beta source used in brachytherapy applications. However, worldwide increase in the use of high energy electron accelerators, new challenges are being posed for radiological protection and the operational quantities defined previously by ICRU are being reviewed. In view of these developments, studies have been performed for different electron beams in the energy range from (4 - 20) MeV generated using a medical linear accelerator. The aim of the study is to measure doses deposited at various depths as defined by ICRU 39 for individual and area monitoring purposes

  17. Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus)

    DEFF Research Database (Denmark)

    Nielsen, Julius; Hedeholm, Rasmus B.; Heinemeier, Jan

    2016-01-01

    The Greenland shark (Somniosus microcephalus), an iconic species of the Arctic Seas, grows slowly and reaches >500 centimeters (cm) in total length, suggesting a life span well beyond those of other vertebrates. Radiocarbon dating of eye lens nuclei from 28 female Greenland sharks (81 to 502 cm i...

  18. Modulation transfer function of a fish-eye lens based on the sixth-order wave aberration theory.

    Science.gov (United States)

    Jia, Han; Lu, Lijun; Cao, Yiqing

    2018-01-10

    A calculation program of the modulation transfer function (MTF) of a fish-eye lens is developed with the autocorrelation method, in which the sixth-order wave aberration theory of ultra-wide-angle optical systems is used to simulate the wave aberration distribution at the exit pupil of the optical systems. The autocorrelation integral is processed with the Gauss-Legendre integral, and the magnification chromatic aberration is discussed to calculate polychromatic MTF. The MTF calculation results of a given example are then compared with those previously obtained based on the fourth-order wave aberration theory of plane-symmetrical optical systems and with those from the Zemax program. The study shows that MTF based on the sixth-order wave aberration theory has satisfactory calculation accuracy even for a fish-eye lens with a large acceptance aperture. And the impacts of different types of aberrations on the MTF of a fish-eye lens are analyzed. Finally, we apply the self-adaptive and normalized real-coded genetic algorithm and the MTF developed in the paper to optimize the Nikon F/2.8 fish-eye lens; consequently, the optimized system shows better MTF performances than those of the original design.

  19. Public Health England survey of eye lens doses in the UK medical sector

    International Nuclear Information System (INIS)

    Ainsbury, E A; Bouffler, S; Gilvin, P; Peters, S; Slack, K; Cocker, M; Holt, E; Williamson, A

    2014-01-01

    The ICRP has recently recommended that the occupational exposure limit for the lens of the eye be reduced to 20 mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv. There has been concern amongst some groups of individuals, particularly interventional cardiologists and radiologists as well as relevant professional bodies, that implementation of these recommendations into UK law will adversely affect working patterns. However, despite a number of informative European studies, there is currently little UK dosimetry data available upon which judgements can effectively be based. In order to address this knowledge gap, Public Health England has carried out a small, targeted survey of UK lens doses to medical staff undertaking procedures likely to involve the highest levels of radiation exposure. Two out of a total of 61 individuals surveyed had projected annual doses which could be close to 20 mSv, measured outside lead glasses. Use of protective equipment was generally good; however, lead glasses were only used by 9 participants. The results of this survey suggest that compliance with the ICRP recommendations is likely to be possible for most individuals in the UK medical sector. (paper)

  20. Multiconjugate adaptive optics applied to an anatomically accurate human eye model.

    Science.gov (United States)

    Bedggood, P A; Ashman, R; Smith, G; Metha, A B

    2006-09-04

    Aberrations of both astronomical telescopes and the human eye can be successfully corrected with conventional adaptive optics. This produces diffraction-limited imagery over a limited field of view called the isoplanatic patch. A new technique, known as multiconjugate adaptive optics, has been developed recently in astronomy to increase the size of this patch. The key is to model atmospheric turbulence as several flat, discrete layers. A human eye, however, has several curved, aspheric surfaces and a gradient index lens, complicating the task of correcting aberrations over a wide field of view. Here we utilize a computer model to determine the degree to which this technology may be applied to generate high resolution, wide-field retinal images, and discuss the considerations necessary for optimal use with the eye. The Liou and Brennan schematic eye simulates the aspheric surfaces and gradient index lens of real human eyes. We show that the size of the isoplanatic patch of the human eye is significantly increased through multiconjugate adaptive optics.

  1. Multiconjugate adaptive optics applied to an anatomically accurate human eye model

    Science.gov (United States)

    Bedggood, P. A.; Ashman, R.; Smith, G.; Metha, A. B.

    2006-09-01

    Aberrations of both astronomical telescopes and the human eye can be successfully corrected with conventional adaptive optics. This produces diffraction-limited imagery over a limited field of view called the isoplanatic patch. A new technique, known as multiconjugate adaptive optics, has been developed recently in astronomy to increase the size of this patch. The key is to model atmospheric turbulence as several flat, discrete layers. A human eye, however, has several curved, aspheric surfaces and a gradient index lens, complicating the task of correcting aberrations over a wide field of view. Here we utilize a computer model to determine the degree to which this technology may be applied to generate high resolution, wide-field retinal images, and discuss the considerations necessary for optimal use with the eye. The Liou and Brennan schematic eye simulates the aspheric surfaces and gradient index lens of real human eyes. We show that the size of the isoplanatic patch of the human eye is significantly increased through multiconjugate adaptive optics.

  2. Hard sphere-like glass transition in eye lens α-crystallin solutions.

    Science.gov (United States)

    Foffi, Giuseppe; Savin, Gabriela; Bucciarelli, Saskia; Dorsaz, Nicolas; Thurston, George M; Stradner, Anna; Schurtenberger, Peter

    2014-11-25

    We study the equilibrium liquid structure and dynamics of dilute and concentrated bovine eye lens α-crystallin solutions, using small-angle X-ray scattering, static and dynamic light scattering, viscometry, molecular dynamics simulations, and mode-coupling theory. We find that a polydisperse Percus-Yevick hard-sphere liquid-structure model accurately reproduces both static light scattering data and small-angle X-ray scattering liquid structure data from α-crystallin solutions over an extended range of protein concentrations up to 290 mg/mL or 49% vol fraction and up to ca. 330 mg/mL for static light scattering. The measured dynamic light scattering and viscosity properties are also consistent with those of hard-sphere colloids and show power laws characteristic of an approach toward a glass transition at α-crystallin volume fractions near 58%. Dynamic light scattering at a volume fraction beyond the glass transition indicates formation of an arrested state. We further perform event-driven molecular dynamics simulations of polydisperse hard-sphere systems and use mode-coupling theory to compare the measured dynamic power laws with those of hard-sphere models. The static and dynamic data, simulations, and analysis show that aqueous eye lens α-crystallin solutions exhibit a glass transition at high concentrations that is similar to those found in hard-sphere colloidal systems. The α-crystallin glass transition could have implications for the molecular basis of presbyopia and the kinetics of molecular change during cataractogenesis.

  3. KCC isoforms in a human lens epithelial cell line (B3) and lens tissue extracts.

    Science.gov (United States)

    Misri, Sandeep; Chimote, Ameet A; Adragna, Norma C; Warwar, Ronald; Brown, Thomas L; Lauf, Peter K

    2006-11-01

    We recently reported potassium-chloride cotransporter activity in human lens epithelial B3 (HLE-B3) cells. The purpose of the present study was to demonstrate in these cells as well as in human lens tissue the potassium-chloride cotransport (KCC) isoforms by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunofluorescence microscopy. Of the four KCC genes known to encode the respective proteins and their spliced variants, RT-PCR with both rat and human primers revealed the predicted cDNA fragments of KCC1, KCC3a, KCC3b, and KCC4 but not KCC2 in both HLE-B3 cells and in human lens tissue extracts from cataractous patients. Polyclonal rabbit (rb) anti-rat (rt) and anti-human (hm) antibodies against rtKCC1 and hmKCC3, respectively, and a commercially available rb-anti-mouse (ms) KCC4 antibody were used. Rb anti-rtKCC1-ECL3 [against epitopes within the large extracellular loop 3 (ECL3)] revealed a 150kDa band in HLE-B3 cells consistent with the known molecular weight of KCC1. Rb anti-hmKCC3-ECL3 yielded three bands of 150, 122 and 105kDa, evidence for the presence of KCC3a, KCC3b and possibly KCC3c isoforms. The 122 and 112kDa bands were also demonstrated by rb anti-hmKCC3-CTD [the C-terminal domain (CTD)]. Rb anti-msKCC4 antibody only showed a 100kDa band in HLE-B3 cells. In the human lens tissues, a 115kDa protein was detected with rb anti-rtKCC1-ECL3 and a 100kDa band with rb anti-msKCC4, however, no bands with rb anti-hmKCC3-ECL3 or rb anti-hmKCC3-CTD. Fluorescence microscopy revealed immunocytochemical cytoplasmic and membrane labeling of HLE-B3 cells with anti-KCC1, -KCC3 (laser confocal microscopy) and -KCC4 antibodies and a Cy3-tagged secondary antibody. Hence HLE-B3 cells expressed proteins of the KCC1, KCC3a, b, and KCC4 isoforms, whereas surgically removed cataractous lens tissue expressed only those of KCC1 and KCC4.

  4. The Use of the Esclera Scleral Contact Lens in the Treatment of Moderate to Severe Dry Eye Disease.

    Science.gov (United States)

    La Porta Weber, Sarah; Becco de Souza, Rodrigo; Gomes, José Álvaro Pereira; Hofling-Lima, Ana Luisa

    2016-03-01

    To evaluate the efficacy of the Esclera scleral contact lens (SCL) treatment and its impact on clinical testing for moderate to severe dry eye disease (DED). Prospective interventional case series. A total of 41 eyes from 25 patients with moderate to severe DED were evaluated for the Esclera SCL treatment. Best-corrected visual acuity (BCVA), tear osmolarity, the Schirmer I test, tear film breakup time (TBUT), corneal and conjunctival staining, meibomian grading, and Ocular Surface Disease Index and SF-36v2 questionnaires were assessed before and after the SCL treatment. These values were compared to assess the real benefit of using SCL as a treatment for DED. Forty-one eyes from 25 patients were fitted with SCL for management of DED. The underlying diseases were Stevens-Johnson syndrome (22 eyes), Sjogren syndrome (11 eyes), graft-vs-host disease (2 eyes), dry eye after keratomileusis in situ (2 eyes), and undifferentiated ocular surface disease (4 eyes). BCVA improved from 0.703 ± 0.55 logMAR with habitual correction to 0.406 ± 0.43 logMAR with SCL (P dry eye symptoms and quality of life as assessed by the OSDI and SF-36v2 questionnaires (both with P dry eye symptoms, and quality of life. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. How do hospital sterilisation procedures affect the response of personal extremity rings and of eye lens TL dosemeters?

    International Nuclear Information System (INIS)

    Kopec, Renata; Bubak, Anna; Budzanowski, Maciej; Sas-Bieniarz, Anna; Szumska, Agnieszka

    2016-01-01

    Stringent standards of hygiene must be applied in medical institutions, especially at operating blocks or during interventional radiology procedures. Medical equipment, including personal dosemeters that have to be worn by medical staff during such procedures, needs therefore to be sterilised. In this study, the effect of various sterilisation procedures has been tested on the dose response of extremity rings and of eye lens dosemeters in which thermoluminescent (TL) detectors (of types MTS-N and MCP-N, respectively) are used. The effects of medical sterilisation procedures were studied: by chemicals, by steam or by ultraviolet (UV), on the dose assessment by extremity rings and by eye lens dosemeters. Since it often happens that a dosemeter is accidentally machine-washed together with protective clothing, the effect of laundering on dose assessment by these dosemeters was also tested. The sterilisation by chemicals is mostly safe for TL detectors assuming that the dosemeters are waterproofed. Following sterilisation by water vapour, the response of these dosemeters diminished by some 30 %, irrespectively of the period of sterilisation; therefore, this method is not recommended. UV sterilisation can be applied to EYE-D TM eye lens dosemeters if their encapsulation is in black. The accidental dosemeter laundry in a washing machine has no impact on measured dose. (authors)

  6. Different alpha crystallin expression in human age-related and congenital cataract lens epithelium.

    Science.gov (United States)

    Yang, Jing; Zhou, Sheng; Guo, Minfei; Li, Yuting; Gu, Jianjun

    2016-05-28

    The purpose of this study was to investigate the different expressions of αA-crystallin and αB-crystallin in human lens epithelium of age-related and congenital cataracts. The central part of the human anterior lens capsule approximately 5 mm in diameter together with the adhering epithelial cells, were harvested and processed within 6 hours after cataract surgery from age-related and congenital cataract patients or from normal eyes of fresh cadavers. The mRNA and soluble protein levels of αA-crystallin and αB-crystallin in the human lens epithelium were detected by real-time PCR and western blots, respectively. The mRNA and soluble protein expressions of αA-crystallin and αB-crystallin in the lens epithelium were both reduced in age-related and congenital cataract groups when compared with the normal control group. However, the degree of α-crystallin loss in the lens epithelium was highly correlated with different cataract types. The α-crystallin expression of the lens epithelium was greatly reduced in the congenital cataract group but only moderately decreased in the age-related cataract group. The reduction of αA-crystallin soluble protein levels in the congenital cataract group was approximately 2.4 fold decrease compared with that of the age-related cataract group, while an mRNA fold change of 1.67 decrease was observed for the age-related cataract group. Similarly, the reduction of soluble protein levels of αB-crystallin in the congenital cataract group was approximately a 1.57 fold change compared with that of the age-related cataract group. A 1.75 fold change for mRNA levels compared with that of the age-related cataract group was observed. The results suggest that the differential loss of α-crystallin in the human lens epithelium could be associated with the different mechanisms of cataractogenesis in age-related versus congenital cataracts, subsequently resulting in different clinical presentations.

  7. Monte-Carlo simulation of proton radiotherapy for human eye

    International Nuclear Information System (INIS)

    Liu Yunpeng; Tang Xiaobin; Xie Qin; Chen Feida; Geng Changran; Chen Da

    2010-01-01

    The 62 MeV proton beam was selected to develop a MCNPX model of the human eye to approximate dose delivered from proton therapy by. In the course of proton therapy, two treatment simulations were considered. The first simulation was an ideal treatment scenario. In this case, the dose of tumor was 50.03 Gy, which was at the level of effective treatment, while other organizations were in the range of acceptable dose. The second case was a worst case scenario to simulate a patient gazing directly into the treatment beam during therapy. The bulk of dose deposited in the cornea, lens, and anterior chamber region. However, the dose of tumor area was zero. The calculated results show an agreement accordance with the relative reference, which confirmed that the MCNPX code can simulate proton radiotherapy perfectly, and is a capable platform for patient planning. The data from the worst case can be used for dose reconstruction of the clinical accident. (authors)

  8. Photoaggregation of crystallins (main proteins of eye lens) under the effect of XeCl laser radiation

    Science.gov (United States)

    Soustov, Lev V.; Chelnokov, Evgeny V.; Bityurin, Nikita M.; Kiselev, A. L.; Nemov, V. V.; Sergeev, Yu. V.; Ostrovsky, Michail A.

    2004-07-01

    UV light is one of primary factors associated with cataract formation in the eye lens. α-, β-, γ-Crystallins maintain lens transparency, and damage to these proteins plays a major role in cataract formation. The effect of XeCl laser radiation (308 nm) on βL-crystallin solution is studied. The strong dependence of protein aggregation kinetics on both laser fluence (w) and repetition rate (F) is investigated. The kinetics features are similar to those of carbonic anhydrase photoaggregation studied previously.

  9. Prediction of Human Eye Fixations using Symmetry

    OpenAIRE

    Kootstra, Gert; Schomaker, Lambert R. B.

    2009-01-01

    Humans are very sensitive to symmetry in visual patterns. Reaction time experiments show that symmetry is detected and recognized very rapidly. This suggests that symmetry is a highly salient feature. Existing computational models of saliency, however, have mainly focused on contrast as a measure of saliency. In this paper, we discuss local symmetry as a measure of saliency. We propose a number of symmetry models and perform an eye-tracking study with human participants viewing photographic i...

  10. Secondary Angle Closure due to Crystalline Lens Dislocation in a Patient with Atopic Dermatitis and Chronic Eye Rubbing

    Directory of Open Access Journals (Sweden)

    Justin Kuiper

    2018-03-01

    Full Text Available Purpose: To report an unusual case of ectopia lentis and angle closure in a patient with chronic eye rubbing. Methods: A 57-year-old male with a history of poorly controlled atopic dermatitis presented with right eye pain, decreased vision, and an intraocular pressure (IOP of 55 mm Hg. He had no past history of ocular disease and no reported history of trauma. He did report a history of chronic eye rubbing. Results: Best corrected visual acuity was hand motions. The examination revealed severe atopic keratoconjunctivitis in both eyes, microcystic corneal edema of the right eye, and 2+ nuclear sclerosis in both eyes. Gonioscopy showed no visible angle structures OD and an open angle OS. Topical and oral IOP-lowering medications and a laser iridotomy were unsuccessful at lowering IOP. He was taken to the operating room for a lensectomy and was found to have 9 clock hours of zonular dehiscence and a dislocated lens. After lensectomy, the IOP improved to 9 mm Hg on postoperative day 1. A follow-up examination at 2 weeks showed improved acuity to 20/150 with a pinhole and an IOP of 10 mm Hg. A dilated examination OS did not reveal significant phacodonesis, and the patient was referred for a possible sutured sulcus lens or anterior chamber intraocular lens. Conclusions: It is important for the provider to consider ectopia lentis in the differential for patients with pupillary block angle closure. For patients with atopic disease, one should be aware that eye rubbing may be a cause of zonular dehiscence, even in the absence of reported trauma or prior intraocular surgery.

  11. HOW DO HOSPITAL STERILISATION PROCEDURES AFFECT THE RESPONSE OF PERSONAL EXTREMITY RINGS AND OF EYE LENS TL DOSEMETERS?

    Science.gov (United States)

    Kopeć, Renata; Bubak, Anna; Budzanowski, Maciej; Sas-Bieniarz, Anna; Szumska, Agnieszka

    2016-09-01

    Stringent standards of hygiene must be applied in medical institutions, especially at operating blocks or during interventional radiology procedures. Medical equipment, including personal dosemeters that have to be worn by medical staff during such procedures, needs therefore to be sterilised. In this study, the effect of various sterilisation procedures has been tested on the dose response of extremity rings and of eye lens dosemeters in which thermoluminescent (TL) detectors (of types MTS-N and MCP-N, respectively) are used. The effects of medical sterilisation procedures were studied: by chemicals, by steam or by ultraviolet (UV), on the dose assessment by extremity rings and by eye lens dosemeters. Since it often happens that a dosemeter is accidentally machine-washed together with protective clothing, the effect of laundering on dose assessment by these dosemeters was also tested. The sterilisation by chemicals is mostly safe for TL detectors assuming that the dosemeters are waterproofed. Following sterilisation by water vapour, the response of these dosemeters diminished by some 30 %, irrespectively of the period of sterilisation; therefore, this method is not recommended. UV sterilisation can be applied to EYE-D™ eye lens dosemeters if their encapsulation is in black. The accidental dosemeter laundry in a washing machine has no impact on measured dose. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. A and B mode ultrasonography in preoperative evaluation of lens and posterior segment of dogs eyes with cataract

    Directory of Open Access Journals (Sweden)

    Bianca C. Martins

    2010-02-01

    Full Text Available Ultrasonography of the lens and posterior segment is an indispensable step in the preoperative evaluation of dogs with cataracts, since ophthalmoscopy is not feasible when there is opacification of the lens. This study evaluated the echographic conditions of cataractous lens and fundus of the eye in dogs affected by cataracts. The study was conducted in 30 dogs (56 eyes, 10 males and 20 females, with different types of cataracts at different stages of development. Echography in A and B modes, simultaneously, was carried out for the examination of the lens and posterior segment. The examinations revealed anterior cortical, posterior cortical and nuclear cataract in 12 eyes (21.4%, anterior cortical, posterior cortical, nuclear and posterior capsular in 23 eyes (41%, anterior cortical, posterior cortical and posterior capsular cataract in one eye (1.7%, anterior cortical and nuclear cataract in one eye (1.7%, anterior cortical, nuclear and posterior capsular cataract in five eyes (8.9%, and anterior cortical cataract in seven eyes (12.5%. Abnormal ultrasonographic alterations were observed in the posterior segment in 26 eyes evaluated (46.4%. Vitreal degeneration was detected in 12 eyes (21.4%, images of vitreal exudate or hemorrhage in seven eyes (12.5%, persistence of hyaloid artery in four eyes (7.1% and lens subluxation in three eyes (5.3%. The results obtained reiterate the importance of ultrasonography in canine patients presented for cataract surgery given that alterations of the posterior segment are difficult to identify in a clinical examination when the lens is opacified.A ultrassonografia do segmento posterior do bulbo do olho é etapa indispensável na avaliação de cães com catarata que serão submetidos à facectomia, uma vez que a oftalmoscopia não é factível quando há opacificação da lente, notadamente nas cataratas maduras. Este estudo avaliou as condições ecográficas da lente cataratogênica e do fundo de olho de c

  13. Communication Aid with Human Eyes Only

    Science.gov (United States)

    Arai, Kohei; Yajima, Kenro

    A communication aid with human eyes only is proposed. A set of candidate character is displayed onto computer screen of relatively small and light Head Mount Display: HMD that is mounted on glasses of which user wears on. When user looks at a candidate character with his/hers left eye while right eye picture is taken with small and light web camera that also is mounted on the glasses. The proposed system can selects 81 characters with two layers of 9 by 9 character candidate image. Other than these there is another selective image including control keys and frequently use of sentences. By using image matching between previously acquired template image for each candidate character and the currently acquired image, the proposed system realizes that which character in the candidates is selected. By using blinking and fix one's eye on combine together, the proposed system recognizes that user determines the selected key from the candidates. The blinking detection method employs a morphologic filter to avoid misunderstanding of dark eye detection due to eyebrows and shadows. Thus user can input sentences. User also may edit the sentences and then the sentences are read with Text to Speech: TTS software tool. Thus the system allows support conversations between handicapped and disabled persons without voice and the others peoples because only the function required for conversation is human eyes. Also the proposed system can be used as an input system for wearable computing systems. Test results by the 6 different able persons show that the proposed system does work with acceptable speed, around 1.5 second / character.

  14. DYNAMIC CHANGES OF THE POSTERIOR POLE OF THE EYE AFTER CATARACT PHACOEMULSIFICATION WITH INTRAOCULAR LENS IMPLANTATION

    Directory of Open Access Journals (Sweden)

    M. Р. Yugay

    2017-01-01

    Full Text Available Objective. To study the effect of uncomplicated phacoemulsification through the corneal incision with implantation of the intraocular lens (IOL for changes in the macular region of the retina. Methods: The study included 35 eyes of 35 patients who underwent uncomplicated phacoemulsification with IOL implantation. The average age of the patients was 67±2,3 years, among them were 19 women and 16 men. Exclusion criteria: retinal pathology (postthrombotic and diabetic retinopathy, wet form of age-related macular degeneration and other diseases of the retina, previous eye injuries, uveitis, intra-operative complications. Retinal thickness in the fovea, the macula, and macular volume were measured by optical coherence tomography on the first day, after 2 weeks, 1 and 3 months after surgery. Results. In the period between the first day and two weeks after surgery there were the statistically significant incensement in retinal thickness in the macula from 306,64±21,15 mkm to 321,46±27,83 mkm (p <0.05, in the fovea from 211,45±20,24 mkm to 218,69±17,84 mkm (p<0.05, macular volume from 8,08±0,35 cubic mm to 8,46±0,54 cubic mm were registered. By the end of the first month after surgery maximum retinal thickness was 327,23±27,16 mkm, thickness in the fovea 220,31±18,63 mkm, macular volume 8,61±0,55 cubic mm. After 3 months, the maximum thickness of the retina reached 325,11±26,13 mkm, in the fovea 220,31±18,63 mkm, macular volume 8,55±0,49 cubic mm. Conclusion. There was an incensement of macular volume and retinal thickness in the period between the first day and two weeks after uncomplicated cataract phacoemulsification with intraocular lens implantation. The growth of these indicators continued within the first month after surgery, three months after phacoemulsification there was a downward trend. This can be important in determining the duration of drug therapy in the postoperative period.

  15. Properties of Fiber Cell Plasma Membranes Isolated from the Cortex and Nucleus of the Porcine Eye Lens

    Science.gov (United States)

    Mainali, Laxman; Raguz, Marija; O’Brien, William J.; Subczynski, Witold K.

    2012-01-01

    The organization and physical properties of the lipid bilayer portion of intact cortical and nuclear fiber cell plasma membranes isolated from the eyes lenses of two-year-old pigs were studied using electron paramagnetic resonance (EPR) spin-labeling. Membrane fluidity, hydrophobicity, and the oxygen transport parameter (OTP) were assessed from the EPR spectra of precisely positioned spin labels. Intact cortical and nuclear membranes, which include membrane proteins, were found to contain three distinct lipid environments. These lipid environments were termed the bulk lipid domain, boundary lipid domain, and trapped lipid domain (lipids in protein aggregates). The amount of boundary and trapped lipids was greater in intact nuclear membranes than in cortical membranes. The properties of intact membranes were compared with the organization and properties of lens lipid membranes made of the total lipid extracts from the lens cortex or nucleus. In cortical lens lipid membranes, only one homogenous environment was detected, which was designated as a bulk lipid domain (phospholipid bilayer saturated with cholesterol). Lens lipid membranes prepared from the lens nucleus possessed two domains, assigned as a bulk lipid domain and a cholesterol bilayer domain (CBD). In intact nuclear membranes, it was difficult to discriminate the CBD, which was clearly detected in nuclear lens lipid membranes because the OTP measured in the CBD is the same as in the domain formed by trapped lipids. The two domains unique to intact membranes—namely, the domain formed by boundary lipids and the domain formed by trapped lipids—were most likely formed due to the presence of membrane proteins. It is concluded that formation of rigid and practically impermeable domains is enhanced in the lens nucleus, indicating changes in membrane composition that may help to maintain low oxygen concentration in this lens region. PMID:22326289

  16. FDTD analysis of temperature elevation in the lens of human and rabbit models due to near-field and far-field exposures at 2.45 GHz

    International Nuclear Information System (INIS)

    Oizumi, T.; Laakso, I.; Hirata, A.; Fujiwara, O.; Watanabe, S.; Taki, M.; Kojima, M.; Sasaki, H.; Sasaki, K.

    2013-01-01

    The eye is said to be one of the most sensitive organs to microwave heating. According to previous studies, the possibility of microwave-induced cataract formation has been experimentally investigated in rabbit and monkey eyes, but not for the human eye due to ethical reasons. In the present study, the temperature elevation in the lens, the skin around the eye and the core temperature of numerical human and rabbit models for far-field and near-field exposures at 2.45 GHz are investigated. The temperature elevations in the human and rabbit models were compared with the threshold temperatures for inducing cataracts, thermal pain in the skin and reversible health effects such as heat exhaustion or heat stroke. For plane-wave exposure, the core temperature elevation is shown to be essential both in the human and in the rabbit models as suggested in the international guidelines and standards. For localised exposure of the human eye, the temperature elevation of the skin was essential, and the lens temperature did not reach its threshold for thermal pain. On the other hand, the lens temperature elevation was found to be dominant for the rabbit eye. (authors)

  17. FDTD analysis of temperature elevation in the lens of human and rabbit models due to near-field and far-field exposures at 2.45 GHz.

    Science.gov (United States)

    Oizumi, Takuya; Laakso, Ilkka; Hirata, Akimasa; Fujiwara, Osamu; Watanabe, Soichi; Taki, Masao; Kojima, Masami; Sasaki, Hiroshi; Sasaki, Kazuyuki

    2013-07-01

    The eye is said to be one of the most sensitive organs to microwave heating. According to previous studies, the possibility of microwave-induced cataract formation has been experimentally investigated in rabbit and monkey eyes, but not for the human eye due to ethical reasons. In the present study, the temperature elevation in the lens, the skin around the eye and the core temperature of numerical human and rabbit models for far-field and near-field exposures at 2.45 GHz are investigated. The temperature elevations in the human and rabbit models were compared with the threshold temperatures for inducing cataracts, thermal pain in the skin and reversible health effects such as heat exhaustion or heat stroke. For plane-wave exposure, the core temperature elevation is shown to be essential both in the human and in the rabbit models as suggested in the international guidelines and standards. For localised exposure of the human eye, the temperature elevation of the skin was essential, and the lens temperature did not reach its threshold for thermal pain. On the other hand, the lens temperature elevation was found to be dominant for the rabbit eye.

  18. Interim report of the JHPS expert committee on radiation protection of the lens of the eye (4). Current activities of ICRP and ICU: External dosimetric concepts for the lens of the eye

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Fujimichi, Yuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Yamauchi-Kawaura, Chiyo; Tsujimura, Norio; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2015-01-01

    The International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) have been defined operational quantities and protection quantities. Dose limits have been also recommended by the ICRP using protection quantities. These quantities and some related values for main radiation such as photons, electrons, and neutrons, are summarized in this article with some historical considerations. The ICRP indicated conversion coefficients for the lens of the eye as absorbed dose per fluence as protection quantities. equivalent dose is not used because a protection quantity that uses radiation weighting factors is not intended to be calculated for tissue reactions. So far, the ICRP has not indicated a specific RBE value for cataract formation. Operational quantities are used for measurements. There have been three types of phantoms, namely a slab phantom, a reduced phantom, and a cylindrical phantom, but none of them has been definitely recommended for the lens of the eye by the ICRP or the ICRU. Although conversion coefficients to personal dose equivalent, H p (3), for electrons have been recommended, no other conversion coefficients to personal dose equivalent for the lens of the eye has been indicated by the ICRP or the ICRU. However, there have been several studies described personal dose equivalent. Ambient dose equivalent, H * (3), and directional dose equivalent, H(3, α), have been indicated in several limited conditions by the ICRP and the ICRU. These status are overviewed in this article. (author)

  19. Implications in dosimetry of the implementation of the revised dose limit to the lens of the eye

    International Nuclear Information System (INIS)

    Broughton, J.; Shah, B.; Cantone, M.C.; Ginjaume, M.; Czarwinski, R.

    2015-01-01

    In 2012, International Radiation Protection Association (IRPA) established a Task Group to provide an assessment of the impact of the implementation of the ICRP-revised dose limit for the lens of the eye for occupational exposure. Associated Societies (ASs) of IRPA were asked to provide views and comments on the basis of a questionnaire addressing three principal topics: (i) implications for dosimetry, (ii) implications for methods of protection and (iii) wider implications of implementing the revised limits. A summary of the collated responses regarding dosimetry is presented and discussed. There is large agreement on the most critical aspects and difficulties in setting up an appropriate monitoring programme for the lens of the eyes. The recent international standards and technical documents provide guidance for some of the concerns but other challenges remain in terms of awareness, acceptance and practicalities. (authors)

  20. Zoonotic helminths affecting the human eye

    Science.gov (United States)

    2011-01-01

    Nowaday, zoonoses are an important cause of human parasitic diseases worldwide and a major threat to the socio-economic development, mainly in developing countries. Importantly, zoonotic helminths that affect human eyes (HIE) may cause blindness with severe socio-economic consequences to human communities. These infections include nematodes, cestodes and trematodes, which may be transmitted by vectors (dirofilariasis, onchocerciasis, thelaziasis), food consumption (sparganosis, trichinellosis) and those acquired indirectly from the environment (ascariasis, echinococcosis, fascioliasis). Adult and/or larval stages of HIE may localize into human ocular tissues externally (i.e., lachrymal glands, eyelids, conjunctival sacs) or into the ocular globe (i.e., intravitreous retina, anterior and or posterior chamber) causing symptoms due to the parasitic localization in the eyes or to the immune reaction they elicit in the host. Unfortunately, data on HIE are scant and mostly limited to case reports from different countries. The biology and epidemiology of the most frequently reported HIE are discussed as well as clinical description of the diseases, diagnostic considerations and video clips on their presentation and surgical treatment. Homines amplius oculis, quam auribus credunt Seneca Ep 6,5 Men believe their eyes more than their ears PMID:21429191

  1. Zoonotic helminths affecting the human eye

    Directory of Open Access Journals (Sweden)

    Eberhard Mark L

    2011-03-01

    Full Text Available Abstract Nowaday, zoonoses are an important cause of human parasitic diseases worldwide and a major threat to the socio-economic development, mainly in developing countries. Importantly, zoonotic helminths that affect human eyes (HIE may cause blindness with severe socio-economic consequences to human communities. These infections include nematodes, cestodes and trematodes, which may be transmitted by vectors (dirofilariasis, onchocerciasis, thelaziasis, food consumption (sparganosis, trichinellosis and those acquired indirectly from the environment (ascariasis, echinococcosis, fascioliasis. Adult and/or larval stages of HIE may localize into human ocular tissues externally (i.e., lachrymal glands, eyelids, conjunctival sacs or into the ocular globe (i.e., intravitreous retina, anterior and or posterior chamber causing symptoms due to the parasitic localization in the eyes or to the immune reaction they elicit in the host. Unfortunately, data on HIE are scant and mostly limited to case reports from different countries. The biology and epidemiology of the most frequently reported HIE are discussed as well as clinical description of the diseases, diagnostic considerations and video clips on their presentation and surgical treatment. Homines amplius oculis, quam auribus credunt Seneca Ep 6,5 Men believe their eyes more than their ears

  2. SU-E-I-57: Estimating the Occupational Eye Lens Dose in Interventional Radiology Using Active Personal Dosimeters Worn On the Chest

    Energy Technology Data Exchange (ETDEWEB)

    Omar, A; Marteinsdottir, M; Kadesjo, N; Fransson, A [Dept. of Medical Physics, Karolinska University Hospital, Stockholm (Sweden)

    2015-06-15

    Purpose: To provide a general formalism for determination of occupational eye lens dose based on the response of an active personal dosimeter (APD) worn at chest level above the radiation protection apron. Methods: The formalism consists of three factors: (1) APD conversion factor converting the reading at chest level (APDchest) to the corresponding personal dose equivalent at eye level, (2) Dose conversion factor transferring the measured dose quantity, Hp(10), into a dose quantity relevant for the eye lens dose, (3) Correction factor accounting for differences in exposure of the eye(s) compared to the exposure at chest level (e.g., due to protective lead glasses).The different factors were investigated and evaluated based on phantom and clinical measurements performed in an x-ray angiography suite for interventional cardiology. Results: The eye lens dose can be conservatively estimated by assigning an appropriate numerical value to each factor entering the formalism that in most circumstances overestimates the dose. Doing so, the eye lens dose to the primary operator and assisting staff was estimated in this work as D-eye,primary = 2.0 APDchest and D-eye,assisting = 1.0 APDchest, respectively.The annual eye lens dose to three nurses and one cardiologist was estimated to be 2, 2, 2, and 13 mSv (Hp(0.07)), respectively, using a TLD dosimeter worn at eye level. In comparison, using the formalism and APDchest measurements, the respective doses were 2, 2, 2, and 16 mSv (Hp(3)). Conclusion: The formalism outlined in this work can be used to estimate the occupational eye lens dose from the response of an APD worn on the chest. The formalism is general and could be applied also to other types of dosimeters. However, the numerical value of the different factors may differ from those obtained with the APD’s used in this work due to differences in dosimeter properties.

  3. SU-E-I-57: Estimating the Occupational Eye Lens Dose in Interventional Radiology Using Active Personal Dosimeters Worn On the Chest

    International Nuclear Information System (INIS)

    Omar, A; Marteinsdottir, M; Kadesjo, N; Fransson, A

    2015-01-01

    Purpose: To provide a general formalism for determination of occupational eye lens dose based on the response of an active personal dosimeter (APD) worn at chest level above the radiation protection apron. Methods: The formalism consists of three factors: (1) APD conversion factor converting the reading at chest level (APDchest) to the corresponding personal dose equivalent at eye level, (2) Dose conversion factor transferring the measured dose quantity, Hp(10), into a dose quantity relevant for the eye lens dose, (3) Correction factor accounting for differences in exposure of the eye(s) compared to the exposure at chest level (e.g., due to protective lead glasses).The different factors were investigated and evaluated based on phantom and clinical measurements performed in an x-ray angiography suite for interventional cardiology. Results: The eye lens dose can be conservatively estimated by assigning an appropriate numerical value to each factor entering the formalism that in most circumstances overestimates the dose. Doing so, the eye lens dose to the primary operator and assisting staff was estimated in this work as D-eye,primary = 2.0 APDchest and D-eye,assisting = 1.0 APDchest, respectively.The annual eye lens dose to three nurses and one cardiologist was estimated to be 2, 2, 2, and 13 mSv (Hp(0.07)), respectively, using a TLD dosimeter worn at eye level. In comparison, using the formalism and APDchest measurements, the respective doses were 2, 2, 2, and 16 mSv (Hp(3)). Conclusion: The formalism outlined in this work can be used to estimate the occupational eye lens dose from the response of an APD worn on the chest. The formalism is general and could be applied also to other types of dosimeters. However, the numerical value of the different factors may differ from those obtained with the APD’s used in this work due to differences in dosimeter properties

  4. Theoretical investigation of aberrations upon ametropic human eyes

    Science.gov (United States)

    Tan, Bo; Chen, Ying-Ling; Lewis, J. W. L.; Baker, Kevin

    2003-11-01

    The human eye aberrations are important for visual acuity and ophthalmic diagnostics and surgical procedures. Reported monochromatic aberration data of the normal 20/20 human eyes are scarce. There exist even fewer reports of the relation between ametropic conditions and aberrations. We theoretically investigate the monochromatic and chromatic aberrations of human eyes for refractive errors of -10 to +10 diopters. Schematic human eye models are employed using optical design software for axial, index, and refractive types of ametropia.

  5. The effects of high-Dk rigid contact lens center thickness, material permeability, and blinking on the oxygen uptake of the human cornea.

    Science.gov (United States)

    Gardner, Hope Patterson; Fink, Barbara A; Mitchell, Lynn G; Hill, Richard M

    2005-06-01

    The human corneal oxygen uptake responses associated with the static (nonblinking) and dynamic (blinking) wear of five rigid gas-permeable materials with high oxygen permeabilities were determined for three different center thicknesses and compared with the responses for the normal open eye and severe hypoxic stress (static wear of polymethylmethacrylate). Corneal oxygen uptake rates were measured with a Clark-type polarographic electrode during two sessions with each of 10 human subjects. Measurements were made on the right eye for the normal open eye (air) and after 5 minutes of static and dynamic wear of polymethylmethacrylate and five rigid gas-permeable contact lens materials: Fluoroperm 92 (paflufocon A, Dk = 92), Fluoroperm 151 (paflufocon D, Dk = 151), 1992 Menicon SF-P (melafocon A, Dk = 102), 1995 Menicon SF-P (melafocon A, Dk = 159), and Menicon Z (tisilfocon A, Dk = 163-250). Lenses were manufactured in three different center thicknesses (0.12, 0.16, and 0.20 mm), with all other parameters remaining constant. Repeated-measures analysis of variance was used and included lens material (five levels), blinking condition (two levels), and lens thickness (three levels) as within-subject effects. Significant differences were found in corneal oxygen responses to lens material (p Dk rigid lens materials studied here, moderate changes in lens thickness or material permeability may result in modest differences in corneal hypoxic relief, whereas blinking results in no significant improvement to corneal oxygenation.

  6. Retropupillary Fixation of Iris-Claw Intraocular Lens for Aphakic Eyes in Children.

    Directory of Open Access Journals (Sweden)

    Martina Brandner

    Full Text Available To report outcome, complications and safety of retropupillary fixated iris-claw intraocular lenses in a pediatric population.Retrospective study.Ten consecutive pediatric patients (15 eyes underwent placement of retropupillary fixated iris-claw intraocular lenses between October 2007 and July 2013 at the Department of Ophthalmology, Medical University Graz and General Hospital Klagenfurt, Austria. Postoperative visual acuity and complications were analyzed.Median final best-corrected visual acuity improved by 0.12 logMAR from preoperative baseline. Mean postoperative spherical equivalent was -0.05 ± 1.76 D. No serious complications were observed intra- or postoperatively during the entire follow-up period of up to 40 months. One patient experienced a haptic disenclavation with IOL subluxation immediately after a car accident.Our study demonstrates that iris-claw intraocular lens implantation behind the iris is safe in children with lack of capsular support and yields excellent visual outcome with low complication rate.

  7. Spontaneous bilateral anterior partial in-the-bag intraocular lens dislocation following routine annual eye examination.

    Science.gov (United States)

    Ford, Joshua R; Werner, Liliana; Owen, Leah; Vasavada, Shail A; Crandall, Alan

    2014-09-01

    We present the case of an 81-year-old man with pseudoexfoliation syndrome (PXF) in whom spontaneous bilateral anterior partial in-the-bag intraocular lens (IOL) dislocation was diagnosed following a routine dilated examination that demonstrated only mild pseudophacodonesis with no evidence of subluxation. Uneventful cataract surgery with placement of single-piece hydrophobic acrylic posterior chamber IOLs had been performed in both eyes 7 years previously. Bilateral IOL repositioning with scleral fixation was performed to correct the dislocation. Postoperative examinations showed remarkable improvement in visual acuity and IOL stability. We hypothesize that zonular weakness secondary to PXF predisposed the patient to bilateral IOL partial dislocation. Pupil dilation in the setting of mild pseudophacodonesis at the time of routine examination may have been a precipitating factor. To our knowledge, bilateral IOL subluxation/dislocation has been described in a limited number of case reports. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  8. Retropupillary Fixation of Iris-Claw Intraocular Lens for Aphakic Eyes in Children

    Science.gov (United States)

    Brandner, Martina; Thaler-Saliba, Sarah; Plainer, Sophie; Vidic, Bertram; El-Shabrawi, Yosuf; Ardjomand, Navid

    2015-01-01

    Purpose To report outcome, complications and safety of retropupillary fixated iris-claw intraocular lenses in a pediatric population. Design Retrospective study. Patients and Methods Ten consecutive pediatric patients (15 eyes) underwent placement of retropupillary fixated iris-claw intraocular lenses between October 2007 and July 2013 at the Department of Ophthalmology, Medical University Graz and General Hospital Klagenfurt, Austria. Postoperative visual acuity and complications were analyzed. Results Median final best-corrected visual acuity improved by 0.12 logMAR from preoperative baseline. Mean postoperative spherical equivalent was -0.05 ± 1.76 D. No serious complications were observed intra- or postoperatively during the entire follow-up period of up to 40 months. One patient experienced a haptic disenclavation with IOL subluxation immediately after a car accident. Conclusion Our study demonstrates that iris-claw intraocular lens implantation behind the iris is safe in children with lack of capsular support and yields excellent visual outcome with low complication rate. PMID:26110864

  9. Dosimetric Comparison of Simulated Human Eye And Water Phantom in Investigation of Iodine Source Effects on Tumour And Healthy Tissues

    International Nuclear Information System (INIS)

    Sadi, A.S.; Masoudi, F.S. K.N.Toosi University of Technology

    2011-01-01

    For better clinical analysis in ophthalmic brachytherapy dosimetry, there is a need for the dose determination in different parts of the eye, so simulating the eye and defining the material of any parts of that, is helpful for better investigating dosimetry in human eye. However in brachytherapy dosimetry, it is common to consider the water phantom as human eye globe. In this work, a full human eye is simulated with MCNP-4C code by considering all parts of the eye like; lens, cornea, retina, choroid, sclera, anterior chamber, optic nerve, bulk of the eye comprising vitreous body and tumour. The average dose in different parts of this full model of human eye is determined and the results are compared with the dose calculated in water phantom. The central axes depth dose and the dose in whole of the tumour for these two simulated eye model are calculated too, and the results are compared. At long last, as the aim of this work is comparing the result of investigating dosimetry between two water phantom as human eye and simulated eye globe, the ratios of the absorbed dose by the healthy tissues to the absorbed dose by the tumour are calculated in these simulations and the comparison between results is done eventually.

  10. Crystalline lens - Eyes under high radiological protection. From regulation to acts. With neuro-radiologists of the Pitie-Salpetriere

    International Nuclear Information System (INIS)

    2014-01-01

    As the limit exposure of workers' crystalline lens to ionizing radiations is about to be lowered, this set of three articles proposes an overview of this specific issue. A recent study performed by the IRSN revealed that interventional cardiologists display four more crystalline lens opacification that the rest of the population, and also revealed that other incidents could affect the eyes of some operators of nuclear medicine. In interventional radiology, fingers, fists and eyes are the most exposed and have not been so well protected as the rest of the body. After dosimetry measurements, the use of protective glasses has been introduced. These protective measures could be applied in other nuclear activities. Studies are being performed on the eyes of children living in areas contaminated by the Chernobyl accident. A second article comments the various actions and initiatives aiming at limiting the dose received by the crystalline lens: preparation of a new regulation for the follow-up of exposed workers, definition of standards for dose measurement devices, risk assessments, recommendation to interventional radiologists to optimize their exposure (process, protective clothes, and so on). A last article briefly reports the implementation of a dose follow-up for interventional neuro-radiologists in a Parisian hospital

  11. Vitamin C degradation products and pathways in the human lens.

    Science.gov (United States)

    Nemet, Ina; Monnier, Vincent M

    2011-10-28

    Vitamin C and its degradation products participate in chemical modifications of proteins in vivo through non-enzymatic glycation (Maillard reaction) and formation of different products called advanced glycation end products. Vitamin C levels are particularly high in selected tissues, such as lens, brain and adrenal gland, and its degradation products can inflict substantial protein damage via formation of advanced glycation end products. However, the pathways of in vivo vitamin C degradation are poorly understood. Here we have determined the levels of vitamin C oxidation and degradation products dehydroascorbic acid, 2,3-diketogulonic acid, 3-deoxythreosone, xylosone, and threosone in the human lens using o-phenylenediamine to trap both free and protein-bound adducts. In the protein-free fraction and water-soluble proteins (WSP), all five listed degradation products were identified. Dehydroascorbic acid, 2,3-diketogulonic acid, and 3-deoxythreosone were the major products in the protein-free fraction, whereas in the WSP, 3-deoxythreosone was the most abundant measured dicarbonyl. In addition, 3-deoxythreosone in WSP showed positive linear correlation with age (p degradation product bound to human lens proteins provides in vivo evidence for the non-oxidative pathway of dehydroascorbate degradation into erythrulose as a major pathway for vitamin C degradation in vivo.

  12. Combination of confocal principle and aperture stop separation improves suppression of crystalline lens fluorescence in an eye model

    OpenAIRE

    Klemm, Matthias; Blum, Johannes; Link, Dietmar; Hammer, Martin; Haueisen, Jens; Schweitzer, Dietrich

    2016-01-01

    Fluorescence lifetime imaging ophthalmoscopy (FLIO) is a new technique to detect changes in the human retina. The autofluorescence decay over time, generated by endogenous fluorophores, is measured in vivo. The strong autofluorescence of the crystalline lens, however, superimposes the intensity decay of the retina fluorescence, as the confocal principle is not able to suppress it sufficiently. Thus, the crystalline lens autofluorescence causes artifacts in the retinal fluorescence lifetimes d...

  13. Ascorbic acid glycation of lens proteins produces UVA sensitizers similar to those in human lens

    International Nuclear Information System (INIS)

    Ortwerth, B.J.; Linetsky, Mikhail; Olesen, P.R.

    1995-01-01

    Soluble calf lens proteins were extensively glycated during a 4 week incubation with ascorbic acid in the presence of oxygen. Amino acids analysis of the dialyzed proteins removed at weekly intervals showed an increasing loss of lysine, arginine and histidine, consistent with the extensive protein cross-linking observed. Irradiation of the dialyzed samples with UVA light (1.0 kJ/cm 2 total illumination through a 338 nm cutoff filter) caused an increasing loss of tryptophan, an additional loss of histidine and the production of micromolar concentrations of hydrogen peroxide. No alteration in amino acid content and no photolytic effects were seen in proteins incubated without ascorbic acid in proteins incubated with glucose for 4 weeks. The rate of hydrogen peroxide formation was linear with each glycated sample with a maximum production of 25 nmol/mg protein illuminated. The possibility that the sensitizer activity was due to an ascorbate-induced oxidation of tryptophan was eliminated by the presence of a heavy metal ion chelator during the incubation and by showing equivalent effects with ascorbate-incubated ribonuclease A, which is devoid of tryptophan. The ascorbate-incubated samples displayed increasing absorbance at wavelengths above 300 nm and increasing fluorescence (340/430) as glycation proceeded. The spectra of the 4 week glycated proteins were identical to those obtained with a solubilized water-insoluble fraction from human lens, which is known to have UVA sensitizer activity. (Author)

  14. 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)

  15. Higher order monochromatic aberrations of the human infant eye

    OpenAIRE

    Wang, Jingyun; Candy, T. Rowan

    2005-01-01

    The monochromatic optical aberrations of the eye degrade retinal image quality. Any significant aberrations during postnatal development could contribute to infants’ immature visual performance and provide signals for the control of eye growth. Aberrations of human infant eyes from 5 to 7 weeks old were compared with those of adult subjects using a model of an adultlike infant eye that accounted for differences in both eye and pupil size. Data were collected using the COAS Shack-Hartmann wave...

  16. The Optical Design of the Human Eye: a Critical Review

    Directory of Open Access Journals (Sweden)

    Rafael Navarro

    2009-01-01

    Full Text Available Cornea, lens and eye models are analyzed and compared to experimental findings to assess properties and eventually unveil optical design principles involved in the structure and function of the optical system of the eye. Models and data often show good match but also some paradoxes. The optical design seems to correspond to a wide angle lens. Compared to conventional optical systems, the eye presents a poor optical quality on axis, but a relatively good quality off-axis, thus yielding higher homogeneity for a wide visual field. This seems the result of an intriguing combination of the symmetry design principle with a total lack of rotational symmetry, decentrations and misalignments of the optical surfaces.

  17. 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.

  18. 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.

  19. SU-F-T-86: Electron Dosimetric Effects of Bolus and Lens Shielding in Treating Superficial Eye Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Young, L [University of Washington Medical Center, Seattle, WA (United States); Wootton, L [University of Washington School of Medicine, Seattle, WA (United States); Gopan, O; Liao, J [University of Washington, Seattle, WA (United States)

    2016-06-15

    Purpose: Electron therapy for the treatment of ocular lymphomas requires the lens to be shielded to prevent secondary cataracts. This work evaluates the dosimetry under a suspended eyeshield with and without bolus for low energy electron fields. Methods: Film (GafChromic EBT3) dosimetry and relative output factors were measured for 6, 8, and 10 MeV electron energies. A customized 5 cm diameter circle electron orbital cutout was constructed for a 6×6 cm applicator with a lens shield, 1 cm diameter Cerrobend cylinder with 2.2 cm length, suspended from an XV film covering the open field. Relative output factors were measured using a Scanditronix electron diode in a solid water phantom. Depth dose profiles were collected for bolus thicknesses of 0, 3, and 5 mm in solid water at a source to surface distance (SSD) of 100 cm. These measurements were repeated in a Rando phantom. Results: At 5 mm, the approximate distance of the lens from the surface of the cornea, the estimated dose in solid water under the suspended lens shield was reduced to 16%, 14%, and 13% of the unblocked dose at the same depth, for electron energies of 6, 8, and 10 MeV, respectively. Applying bolus increased estimated doses under the block to 22% for 3-mm and 32% for 5-mm thicknesses for a 6 MeV incident electron beam. This effect is reduced for higher energies where the corresponding values were 15.5% and 18% for 3-mm and 5-mm for an 8 MeV electron beam. Conclusion: The application of bolus to treat superficial eye lesions of the conjunctiva increases lens dose at a depth of 5-mm under the shielding block with decreasing electron energy. Careful selection of electron energy is needed to account for electron scatter under the lens shield with the application of bolus in order to prevent cataracts.

  20. Interim report of the JHPS expert committee on radiation protection of the lens of the eye (5). Current occupational radiation exposure of the lens of the eye in Japan

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Fujimichi, Yuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Yamauchi-Kawaura, Chiyo; Tsujimura, Norio; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2015-01-01

    For many Japanese radiation workers in the medical, nuclear and other industrial fields, the equivalent dose of the lens of the eye will be sufficiently lower than the new ICRP dose limit. However, the dose of the eye for medical staff members who are engaged in interventional radiology and cardiology may exceed the new ICRP dose limit, especially when they are exposed closely to higher scatter radiation for a long time. In addition, the radiation dosimetry and radiation protection for emergency and recovery workers in the Fukushima Daiichi Nuclear Power Plant (FNPP1) are important issues. Thus gathering information related to the radiation dose and protection for Japanese radiation workers is important to a discussion regarding implementation of the new ICRP dose limit for the lens of the eye for Japanese regulations and planning radiation dose reduction measures. In this paper, recent studies and issues regarding radiation exposure and protection in the medical, nuclear and other industrial fields, as well as for emergency and recovery workers in the FNPP1 were summarized. (author)

  1. Cyclooxygenase-2 expression in the normal human eye and its expression pattern in selected eye tumours

    DEFF Research Database (Denmark)

    Wang, Jinmei; Wu, Yazhen; Heegaard, Steffen

    2011-01-01

    Purpose: Cyclooxygenase-2 (COX-2) is an enzyme involved in neoplastic processes. The purpose of the present study is to investigate COX-2 expression in the normal human eye and the expression pattern in selected eye tumours involving COX-2 expressing cells. Methods: Immunohistochemical staining...... using antibodies against COX-2 was performed on paraffin sections of normal human eyes and selected eye tumours arising from cells expressing COX-2. Results: Cyclooxygenase-2 expression was found in various structures of the normal eye. Abundant expression was seen in the cornea, iris, ciliary body...... and retina. The COX-2 expression was less in tumours deriving from the ciliary epithelium and also in retinoblastoma. Conclusion: Cyclooxygenase-2 is constitutively expressed in normal human eyes. The expression of COX-2 is much lower in selected eye tumours involving COX-2 expressing cells....

  2. Your Eyes

    Science.gov (United States)

    ... away? If you guessed the eye, you're right! Your eyes are at work from the moment you wake up to the ... the eye is seeing. A Muscle Makes It Work The lens is suspended in ... of the lens. That's right — the lens actually changes shape right inside your ...

  3. Photodamaging mechanism of the eye structure: UV effect on soluble proteins of the lens

    International Nuclear Information System (INIS)

    Korkhmazyan, M.M.; Fedorovich, I.B.; Ostrovskij, M.A.

    1983-01-01

    Damaging effect of UV-radiation on soluble proteins of bull lens has been studied. Irradiation results in lens proteins growing yellow, new absorption bands with the maxima 245 and 305 nm appear. It is shown that during photodamage oxidation of SH-groups takes place and protein aggregates are formed

  4. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

    2016-10-15

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

  5. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

    International Nuclear Information System (INIS)

    Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian

    2016-01-01

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

  6. Low-dose CT of the paranasal sinuses with eye lens protection: effect on image quality and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Hein, Eike; Rogalla, Patrik; Klingebiel, Randolph; Hamm, Bernd [Department of Diagnostic and Interventional Radiology, Charite Hospital, Humboldt-Universitaet zu Berlin (Germany)

    2002-07-01

    The purpose of the study was to assess the effect of lens protection on image quality and radiation dose to the eye lenses in CT of the paranasal sinuses. In 127 patients referred to rule out sinusitis, an axial spiral CT with a lens protection placed on the patients eyes was obtained (1.5/2/1, 50 mAs, 120 kV). Coronal views were reconstructed at 5-mm interval. To quantify a subjective impression of image quality, three regions of interest within the eyeball were plotted along a line perpendicular to the protection at 2, 5, and 9 mm beneath skin level on the axial images. Additionally, dose reduction of a bismuth-containing latex shield was measured using a film-dosimetry technique. The average eyeball density was 17.97 HU (SD 3.7 HU). The relative increase in CT density was 180.6 (17.7), 103.3 (11.7), and 53.6 HU (9.2), respectively. There was no diagnostic information loss on axial and coronal views observed. Artifacts were practically invisible on images viewed in a bone window/level setting. The use of the shield reduced skin radiation from 7.5 to 4.5 mGy. The utilization of a radioprotection to the eye lenses in paranasal CT is a suitable and effective means of reducing skin radiation by 40%. (orig.)

  7. Low-dose CT of the paranasal sinuses with eye lens protection: effect on image quality and radiation dose

    International Nuclear Information System (INIS)

    Hein, Eike; Rogalla, Patrik; Klingebiel, Randolph; Hamm, Bernd

    2002-01-01

    The purpose of the study was to assess the effect of lens protection on image quality and radiation dose to the eye lenses in CT of the paranasal sinuses. In 127 patients referred to rule out sinusitis, an axial spiral CT with a lens protection placed on the patients eyes was obtained (1.5/2/1, 50 mAs, 120 kV). Coronal views were reconstructed at 5-mm interval. To quantify a subjective impression of image quality, three regions of interest within the eyeball were plotted along a line perpendicular to the protection at 2, 5, and 9 mm beneath skin level on the axial images. Additionally, dose reduction of a bismuth-containing latex shield was measured using a film-dosimetry technique. The average eyeball density was 17.97 HU (SD 3.7 HU). The relative increase in CT density was 180.6 (17.7), 103.3 (11.7), and 53.6 HU (9.2), respectively. There was no diagnostic information loss on axial and coronal views observed. Artifacts were practically invisible on images viewed in a bone window/level setting. The use of the shield reduced skin radiation from 7.5 to 4.5 mGy. The utilization of a radioprotection to the eye lenses in paranasal CT is a suitable and effective means of reducing skin radiation by 40%. (orig.)

  8. Human eye analytical and mesh-geometry models for ophthalmic dosimetry using MCNP6

    International Nuclear Information System (INIS)

    Angelocci, Lucas V.; Fonseca, Gabriel P.; Yoriyaz, Helio

    2015-01-01

    Eye tumors can be treated with brachytherapy using Co-60 plaques, I-125 seeds, among others materials. The human eye has regions particularly vulnerable to ionizing radiation (e.g. crystalline) and dosimetry for this region must be taken carefully. A mathematical model was proposed in the past [1] for the eye anatomy to be used in Monte Carlo simulations to account for dose distribution in ophthalmic brachytherapy. The model includes the description for internal structures of the eye that were not treated in previous works. The aim of this present work was to develop a new eye model based on the Mesh geometries of the MCNP6 code. The methodology utilized the ABAQUS/CAE (Simulia 3DS) software to build the Mesh geometry. For this work, an ophthalmic applicator containing up to 24 model Amersham 6711 I-125 seeds (Oncoseed) was used, positioned in contact with a generic tumor defined analytically inside the eye. The absorbed dose in eye structures like cornea, sclera, choroid, retina, vitreous body, lens, optical nerve and optical nerve wall were calculated using both models: analytical and MESH. (author)

  9. Human eye analytical and mesh-geometry models for ophthalmic dosimetry using MCNP6

    Energy Technology Data Exchange (ETDEWEB)

    Angelocci, Lucas V.; Fonseca, Gabriel P.; Yoriyaz, Helio, E-mail: hyoriyaz@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Eye tumors can be treated with brachytherapy using Co-60 plaques, I-125 seeds, among others materials. The human eye has regions particularly vulnerable to ionizing radiation (e.g. crystalline) and dosimetry for this region must be taken carefully. A mathematical model was proposed in the past [1] for the eye anatomy to be used in Monte Carlo simulations to account for dose distribution in ophthalmic brachytherapy. The model includes the description for internal structures of the eye that were not treated in previous works. The aim of this present work was to develop a new eye model based on the Mesh geometries of the MCNP6 code. The methodology utilized the ABAQUS/CAE (Simulia 3DS) software to build the Mesh geometry. For this work, an ophthalmic applicator containing up to 24 model Amersham 6711 I-125 seeds (Oncoseed) was used, positioned in contact with a generic tumor defined analytically inside the eye. The absorbed dose in eye structures like cornea, sclera, choroid, retina, vitreous body, lens, optical nerve and optical nerve wall were calculated using both models: analytical and MESH. (author)

  10. Aspartic acid racemization rate in narwhal (Monodon monoceros) eye lens nuclei estimated by counting of growth layers in tusks

    DEFF Research Database (Denmark)

    Garde, Eva; Heide-Jørgensen, Mads Peter; Ditlevsen, Susanne

    2012-01-01

    Ages of marine mammals have traditionally been estimated by counting dentinal growth layers in teeth. However, this method is difficult to use on narwhals (Monodon monoceros) because of their special tooth structures. Alternative methods are therefore needed. The aspartic acid racemization (AAR......) technique has been used in age estimation studies of cetaceans, including narwhals. The purpose of this study was to estimate a species-specific racemization rate for narwhals by regressing aspartic acid D/L ratios in eye lens nuclei against growth layer groups in tusks (n=9). Two racemization rates were...

  11. Virtual pharmacokinetic model of human eye.

    Science.gov (United States)

    Kotha, Sreevani; Murtomäki, Lasse

    2014-07-01

    A virtual pharmacokinetic 3D model of the human eye is built using Comsol Multiphysics® software, which is based on the Finite Element Method (FEM). The model considers drug release from a polymer patch placed on sclera. The model concentrates on the posterior part of the eye, retina being the target tissue, and comprises the choroidal blood flow, partitioning of the drug between different tissues and active transport at the retina pigment epithelium (RPE)-choroid boundary. Although most straightforward, in order to check the mass balance, no protein binding or metabolism is yet included. It appeared that the most important issue in obtaining reliable simulation results is the finite element mesh, while time stepping has hardly any significance. Simulations were extended to 100,000 s. The concentration of a drug is shown as a function of time at various points of retina, as well as its average value, varying several parameters in the model. This work demonstrates how anybody with basic knowledge of calculus is able to build physically meaningful models of quite complex biological systems. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Occupational dose constraints for the lens of the eye for interventional radiologists and interventional cardiologists in the UK.

    Science.gov (United States)

    Mairs, William DA

    2016-06-01

    The International Commission on Radiological Protection (ICRP) has recommended a 20 mSv year(-1) dose limit for the lens of the eye, which has been adopted in the European Union Basic Safety Standards. Interventional radiologists (IRs) and interventional cardiologists (ICs) are likely to be affected by this. The effects of radiation in the lens are somewhat uncertain, and the ICRP explicitly recommend optimization. Occupational dose constraints are part of the optimization process and define a level of dose which ought to be achievable in a well-managed practice. This commentary calls on the professional bodies to review a need for national constraints to guide local decisions. Consideration is given to developing such constraints using maximum expected doses in high-workload facilities with good radiation protection practices and application of a factor allowing for attenuation by lead glasses (LG). Doses are based on a Public Health England survey of eye dose in the UK. Maximum expected doses for ICs are approximately 21 mSv year(-1), neglecting LG. However, the extent of IR exposure is not yet fully known, and further evidence is required before conclusions are drawn. A Health and Safety Laboratory review of LG established a conservative dose reduction factor of 3 for models available in 2012. Application of this factor provides a dose constraint of 7 mSv year(-1) to the eye for ICs. To achieve this constraint, those employers with the most exposed ICs will have to provide and ensure the correct use of a ceiling-suspended eye shield and LG.

  13. Acid phosphatase and lipid peroxidation in human cataractous lens epithelium

    Directory of Open Access Journals (Sweden)

    Vasavada Abhay

    1993-01-01

    Full Text Available The anterior lens epithelial cells undergo a variety of degenerative and proliferative changes during cataract formation. Acid phosphatase is primarily responsible for tissue regeneration and tissue repair. The lipid hydroperoxides that are obtained by lipid peroxidation of polysaturated or unsaturated fatty acids bring about deterioration of biological membranes at cellular and tissue levels. Acid phosphatase and lipid peroxidation activities were studied on the lens epithelial cells of nuclear cataract, posterior subcapsular cataract, mature cataract, and mixed cataract. Of these, mature cataractous lens epithelium showed maximum activity for acid phosphatase (516.83 moles of p-nitrophenol released/g lens epithelium and maximum levels of lipid peroxidation (86.29 O.D./min/g lens epithelium. In contrast, mixed cataractous lens epithelium showed minimum activity of acid phosphatase (222.61 moles of p-nitrophenol released/g lens epithelium and minimum levels of lipid peroxidation (54.23 O.D./min/g lens epithelium. From our study, we correlated the maximum activity of acid phosphatase in mature cataractous lens epithelium with the increased areas of superimposed cells associated with the formation of mature cataract. Likewise, the maximum levels of lipid peroxidation in mature cataractous lens epithelium was correlated with increased permeability of the plasma membrane. Conversely, the minimum levels of lipid peroxidation in mixed cataractous lens epithelium makes us presume that factors other than lipid peroxidation may also account for the formation of mixed type of cataract.

  14. Age-related changes in spectral transmittance of the human crystalline lens in situ.

    Science.gov (United States)

    Sakanishi, Yoshihito; Awano, Masakazu; Mizota, Atsushi; Tanaka, Minoru; Murakami, Akira; Ohnuma, Kazuhiko

    2012-01-01

    It was the aim of this study to measure spectral transmission of the human crystalline lens in situ. The crystalline lens was illuminated by one of four light-emitting diodes of different colors. The relative spectral transmittance of the human crystalline lens was measured with the Purkinje-Sanson mirror images over a wide range of ages. The study evaluated 36 crystalline lenses of 28 subjects aged 21-76 years. There was a significant correlation between the age and spectral transmittance for blue light. Spectral transmittance of the crystalline lens in situ could be measured with Purkinje-Sanson mirror images. Copyright © 2012 S. Karger AG, Basel.

  15. 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.

  16. Regulation of potassium transport in human lens epithelial cells.

    Science.gov (United States)

    Lauf, Peter K; Warwar, Ronald; Brown, Thomas L; Adragna, Norma C

    2006-01-01

    The major K influx pathways and their response to thiol modification by N-ethylmaleimide (NEM) and protein kinase and phosphatase inhibitors were characterized in human lens epithelial B3 (HLE-B3) cells with Rb as K congener. Ouabain (0.1 mM) and bumetanide (5 microM) discriminated between the Na/K pump ( approximately 35% of total Rb influx) and Na-K-2Cl cotransport (NKCC) ( approximately 50%). Cl-replacement with nitrate or sulfamate revealed 100 microM, activated the Na/K pump and abolished NKCC but did not affect KCC. The data suggest at least partial inverse regulation of KCC and NKCC in HLE-B3 cells by signaling cascades involving serine, threonine and tyrosine phosphorylation/dephosphorylation equilibria.

  17. Addendum report of the JHPS expert committee on radiation protection of the lens of the eye (3). Recent related overseas activities

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Kawaura, Chiyo; Tsujimura, Norio; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2015-01-01

    Following the Statement on Tissue Reaction issued by the International Commission on Radiological Protection (ICRP), revisions and discussions are underway in various international organizations about the standards, guidelines and methods for the eye dosimetry. We have previously discussed these issues in six interim reports, followed by two addendum reports on lens dosimetry. This addendum report reviews ongoing overseas discussion and work in relation to research on radiogenic cataracts and implementation of the new eye lens dose limit, such as those in the European Commission, Low Dose Research towards Multidisciplinary Integration (DoReMi), Open Project for European Radiation Research Area (OPERRA), and the Unite Sates National Council on Radiation Protection and Measurements (NCRP). This report serves as the last part of a series of reports by the Japan Health Physics Society Expert Committee on Radiation Protection of the Lens of the Eye. (author)

  18. Determination of positions of optical elements of the human eye

    International Nuclear Information System (INIS)

    Galetskii, S O; Cherezova, T Yu

    2009-01-01

    An original method for noninvasive determining the positions of elements of intraocular optics is proposed. The analytic dependence of the measurement error on the optical-scheme parameters and the restriction in distance from the element being measured are determined within the framework of the method proposed. It is shown that the method can be efficiently used for determining the position of elements in the classical Gullstrand eye model and personalised eye models. The positions of six optical surfaces of the Gullstrand eye model and four optical surfaces of the personalised eye model can be determined with an error of less than 0.25 mm. (human eye optics)

  19. 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).

  20. Computing the influences of different Intraocular Pressures on the human eye components using computational fluid-structure interaction model.

    Science.gov (United States)

    Karimi, Alireza; Razaghi, Reza; Navidbakhsh, Mahdi; Sera, Toshihiro; Kudo, Susumu

    2017-01-01

    Intraocular Pressure (IOP) is defined as the pressure of aqueous in the eye. It has been reported that the normal range of IOP should be within the 10-20 mmHg with an average of 15.50 mmHg among the ophthalmologists. Keratoconus is an anti-inflammatory eye disorder that debilitated cornea unable to reserve the normal structure contrary to the IOP in the eye. Consequently, the cornea would bulge outward and invoke a conical shape following by distorted vision. In addition, it is known that any alterations in the structure and composition of the lens and cornea would exceed a change of the eye ball as well as the mechanical and optical properties of the eye. Understanding the precise alteration of the eye components' stresses and deformations due to different IOPs could help elucidate etiology and pathogenesis to develop treatments not only for keratoconus but also for other diseases of the eye. In this study, at three different IOPs, including 10, 20, and 30 mmHg the stresses and deformations of the human eye components were quantified using a Three-Dimensional (3D) computational Fluid-Structure Interaction (FSI) model of the human eye. The results revealed the highest amount of von Mises stress in the bulged region of the cornea with 245 kPa at the IOP of 30 mmHg. The lens was also showed the von Mises stress of 19.38 kPa at the IOPs of 30 mmHg. In addition, by increasing the IOP from 10 to 30 mmHg, the radius of curvature in the cornea and lens was increased accordingly. In contrast, the sclera indicated its highest stress at the IOP of 10 mmHg due to over pressure phenomenon. The variation of IOP illustrated a little influence in the amount of stress as well as the resultant displacement of the optic nerve. These results can be used for understanding the amount of stresses and deformations in the human eye components due to different IOPs as well as for clarifying significant role of IOP on the radius of curvature of the cornea and the lens.

  1. Reactive Oxygen Species and the Aging Eye: Specific Role of Metabolically Active Mitochondria in Maintaining Lens Function and in the Initiation of the Oxidation-Induced Maturity Onset Cataract--A Novel Platform of Mitochondria-Targeted Antioxidants With Broad Therapeutic Potential for Redox Regulation and Detoxification of Oxidants in Eye Diseases.

    Science.gov (United States)

    Babizhayev, Mark A; Yegorov, Yegor E

    2016-01-01

    The aging eye appears to be at considerable risk from oxidative stress. A great deal of research indicates that dysfunctional mitochondria are the primary site of reactive oxygen species (ROS). More than 95% of O2 produced during normal metabolism is generated by the electron transport chain in the inner mitochondrial membrane. Mitochondria are also the major target of ROS. Cataract formation, the opacification of the eye lens, is one of the leading causes of human blindness worldwide, accounting for 47.8% of all causes of blindness. Cataracts result from the deposition of aggregated proteins in the eye lens and lens fiber cell plasma membrane damage, which causes clouding of the lens, light scattering, and obstruction of vision. ROS-induced damage in the lens cell may consist of oxidation of proteins, DNA damage, and/or lipid peroxidation, all of which have been implicated in cataractogenesis. This article is an attempt to integrate how mitochondrial ROS are altered in the aging eye along with those protective and repair therapeutic systems believed to regulate ROS levels in ocular tissues and how damage to these systems contributes to age-onset eye disease and cataract formation. Mitochondria-targeted antioxidants might be used to effectively prevent ROS-induced oxidation of lipids and proteins in the inner mitochondrial membrane in vivo. As a result of the combination of weak metal chelating, OH and lipid peroxyl radicals scavenging, reducing activities to liberated fatty acid, and phospholipid hydroperoxides, carnosine and carcinine appear to be physiological antioxidants able to efficiently protect the lipid phase of biologic membranes and aqueous environments and act as the antiapoptotic natural drug compounds The authors developed and patented the new ophthalmic compositions, including N-acetylcarnosine, acting as a prodrug of naturally targeted to mitochondria L-carnosine endowed with pluripotent antioxidant activities combined with mitochondria

  2. Eye lens dosimetry for fluoroscopically guided clinical procedures: practical approaches to protection and dose monitoring

    International Nuclear Information System (INIS)

    Martin, Colin J.

    2016-01-01

    Doses to the eye lenses of clinicians undertaking fluoroscopically guided procedures can exceed the dose annual limit of 20 mSv, so optimisation of radiation protection is essential. Ceiling-suspended shields and disposable radiation absorbing pads can reduce eye dose by factors of 2-7. Lead glasses that shield against exposures from the side can lower doses by 2.5-4.5 times. Training in effective use of protective devices is an essential element in achieving good protection and acceptable eye doses. Effective methods for dose monitoring are required to identify protection issues. Dosemeters worn adjacent to the eye provide the better option for interventional clinicians, but an unprotected dosemeter worn at the neck will give an indication of eye dose that is adequate for most interventional staff. Potential requirements for protective devices and dose monitoring can be determined from risk assessments using generic values for dose linked to examination workload. (author)

  3. Eye lens exposure to medical staff performing electrophysiology procedures: dose assessment and correlation to patient dose

    International Nuclear Information System (INIS)

    Ciraj-Bjelac, Olivera; Bozovic, Predrag; Arandjic, Danijela; Antic, Vojislav; Selakovic, Jovana; Pavlovic, Sinisa

    2016-01-01

    The purpose of this study was to assess the patient exposure and staff eye dose levels during implantation procedures for all types of pacemaker therapy devices performed under fluoroscopic guidance and to investigate potential correlation between patients and staff dose levels. The mean eye dose during pacemaker/defibrillator implementation was 12 μSv for the first operator, 8.7 μSv for the second operator/nurse and 0.50 μSv for radiographer. Corresponding values for cardiac re-synchronisation therapy procedures were 30, 26 and 2.0 μSv, respectively. Significant (p < 0.01) correlation between the eye dose and the kerma-area product was found for the first operator and radiographers, but not for other staff categories. The study revealed eye dose per procedure and eye dose normalised to patient dose indices for different staff categories and provided an input for radiation protection in electrophysiology procedures. (authors)

  4. A novel algorithm for automatic localization of human eyes

    Institute of Scientific and Technical Information of China (English)

    Liang Tao (陶亮); Juanjuan Gu (顾涓涓); Zhenquan Zhuang (庄镇泉)

    2003-01-01

    Based on geometrical facial features and image segmentation, we present a novel algorithm for automatic localization of human eyes in grayscale or color still images with complex background. Firstly, a determination criterion of eye location is established by the prior knowledge of geometrical facial features. Secondly,a range of threshold values that would separate eye blocks from others in a segmented face image (I.e.,a binary image) are estimated. Thirdly, with the progressive increase of the threshold by an appropriate step in that range, once two eye blocks appear from the segmented image, they will be detected by the determination criterion of eye location. Finally, the 2D correlation coefficient is used as a symmetry similarity measure to check the factuality of the two detected eyes. To avoid the background interference, skin color segmentation can be applied in order to enhance the accuracy of eye detection. The experimental results demonstrate the high efficiency of the algorithm and correct localization rate.

  5. Eye lens dose correlations with personal dose equivalent and patient exposure in paediatric interventional cardiology performed with a fluoroscopic biplane system.

    Science.gov (United States)

    Alejo, L; Koren, C; Corredoira, E; Sánchez, F; Bayón, J; Serrada, A; Guibelalde, E

    2017-04-01

    To analyse the correlations between the eye lens dose estimates performed with dosimeters placed next to the eyes of paediatric interventional cardiologists working with a biplane system, the personal dose equivalent measured on the thorax and the patient dose. The eye lens dose was estimated in terms of H p (0.07) on a monthly basis, placing optically stimulated luminescence dosimeters (OSLDs) on goggles. The H p (0.07) personal dose equivalent was measured over aprons with whole-body OSLDs. Data on patient dose as recorded by the kerma-area product (P KA ) were collected using an automatic dose management system. The 2 paediatric cardiologists working in the facility were involved in the study, and 222 interventions in a 1-year period were evaluated. The ceiling-suspended screen was often disregarded during interventions. The annual eye lens doses estimated on goggles were 4.13±0.93 and 4.98±1.28mSv. Over the aprons, the doses obtained were 10.83±0.99 and 11.97±1.44mSv. The correlation between the goggles and the apron dose was R 2 =0.89, with a ratio of 0.38. The correlation with the patient dose was R 2 =0.40, with a ratio of 1.79μSvGy -1 cm -2 . The dose per procedure obtained over the aprons was 102±16μSv, and on goggles 40±9μSv. The eye lens dose normalized to P KA was 2.21±0.58μSvGy -1 cm -2 . Measurements of personal dose equivalent over the paediatric cardiologist's apron are useful to estimate eye lens dose levels if no radiation protection devices are typically used. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  6. [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.

  7. Dislocation of polyfocal full-optics accommodative intraocular lens after neodymium-doped yttrium aluminum garnet capsulotomy in vitrectomized eye

    Directory of Open Access Journals (Sweden)

    Kyung Tae Kang

    2013-01-01

    Full Text Available We report a case of dislocation of WIOL-CF® polyfocal full-optics intraocular lens (IOL after neodymium-doped yttrium aluminum garnet (Nd: YAG laser capsulotomy in the vitrectomized eye. At 22 months before the dislocation of the IOL, a 55-year-old male patient underwent phacoemulsification with WIOL-CF® IOL implantation in a local clinic and 10 months after the cataract surgery the patient underwent pars plana vitrectomy, endolaser photocoagulation and 14% C 3 F 8 gas tamponade for the treatment of rhegmatogenous retinal detachment. At 9 months after the vitrectomy, the patient visited our clinic for a sudden decrease of vision after Nd: YAG capsulotomy in the local clinic. On fundus examination, the dislocated IOL was identified and the Nd: YAG capsulotomy site and the larger break, which is suspected to have been a route of the dislocation were observed in the posterior capsule.

  8. Provision of dosimeters by official monitoring services for eye lens dose estimation; Die Bereitstellung von Dosimetern durch die amtlichen Messstellen zur Abschaetzung der Augenlinsendosis

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, J.; Martini, E. [Landesanstalt fuer Personendosimetrie und Strahlenschutzausbildung Mecklenburg-Vorpommern, Berlin (Germany)

    2013-07-01

    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{sub 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{sub 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.)

  9. THE THEORY OF CIVILIZATIONS THROUGH THE LENS OF CONTEMPORARY HUMANITIES

    Directory of Open Access Journals (Sweden)

    T. V. Danylova

    2016-06-01

    Full Text Available Purpose. This paper invites reflections on the further development of civilizational theory through the lens of contemporary humanities. It argues that philosophy is one of the key dimensions of the integral theory of civilizations. The purpose is to promote dialogue-rich interdisciplinary civilizational approach with philosophical understanding of human essence at its core. Methodology. The author has used comparative historical analysis, along with hermeneutical methodology and interdisciplinary approach. Theoretical basis and results. Faced with the challenges of our time, researchers are turning to the civilizational approach, according to which world history appears to us as a colourful spectrum of the options for the development of humanity. At the present stage of scientific development the integral theory of civilizations seems to be the most productive tool for the interpretation of the events taking place in our world. Origianlity. The problem of human being is a key factor in understanding the dynamics of civilizational process and designing a promising theory of civilizations. Philosophy should occupy an important place in the development of a new theory of civilizations: philosophy is the spiritual quintessence of every epoch, every cultural and civilizational community. In particular, a new theory has to take into account both classic and contemporary investigations in the field of philosophical anthropology and theory of values. The increasing threat posed by the clash of civilizations can become a swan song of humanity. For the preservation and further development of the world civilization, there is no other choice but to elaborate the strategies, mechanisms for consultation and dialogue, cooperation and partnership of civilizations and states. That is why the urgent task is to create the certain philosophical position that will contribute to mutual understanding. Conclusions. It is important to involve philosophers in the

  10. Indentation and needle insertion properties of the human eye.

    Science.gov (United States)

    Matthews, A; Hutnik, C; Hill, K; Newson, T; Chan, T; Campbell, G

    2014-07-01

    Characterization of the biomechanical properties of the human eye has a number of potential utilities. One novel purpose is to provide the basis for development of suitable tissue-mimicking material. The purpose of this study was to determine the indentation and needle insertion characteristics on human eye globes and tissue strips. An indenter assessed the elastic response of human eye globes and tissue strips under increasing compressive loads. Needle insertion determined the force (N) needed to penetrate various areas of the eye wall. The results demonstrated that globes underwent slightly greater indentation at the midline than at the central cornea, and corneal strips indented twofold more than scleral strips, although neither difference was significant (P=0.400 and P=0.100, respectively). Significant differences were observed among various areas of needle insertion (Phuman eye construct with potential utility as a model for use in ophthalmology research and surgical teaching.

  11. Proposals for the type tests criteria and calibration conditions of passive eye lens dosemeters to be used in interventional cardiology and radiology workplaces

    International Nuclear Information System (INIS)

    Bordy, J.M.; Daures, J.; Denozière, M.; Gualdrini, G.; Ginjaume, M.; Carinou, E.; Vanhavere, F.

    2011-01-01

    The paper is aimed at making a proposal for the type test and calibration of eye lens passive dosemeters especially used in the interventional cardiology/radiology (IC/IR). Starting from the only existing standard dealing with eye lens dosimetry using TLDs (), parameters such as, detection threshold, energy and angle dependence of response criteria have been reviewed and it has been tried to harmonise them as much as possible with the IEC 62387 requirements, taking into account the particular use at IC/IR workplaces. Conversion coefficients from air kerma to dose equivalent at 3 mm depth for RQR and ISO radiation qualities, employed for type test and calibration purposes, have been calculated in a new phantom introduced within the ORAMED (Optimization of RAdiation protection for MEDical staff) project. This phantom is more representative of the head so that the estimation of H lens by H p (3) is more accurate.

  12. Finite element modelling of radial lentotomy cuts to improve the accommodation performance of the human lens.

    Science.gov (United States)

    Burd, H J; Wilde, G S

    2016-04-01

    The use of a femtosecond laser to form planes of cavitation bubbles within the ocular lens has been proposed as a potential treatment for presbyopia. The intended purpose of these planes of cavitation bubbles (referred to in this paper as 'cutting planes') is to increase the compliance of the lens, with a consequential increase in the amplitude of accommodation. The current paper describes a computational modelling study, based on three-dimensional finite element analysis, to investigate the relationship between the geometric arrangement of the cutting planes and the resulting improvement in lens accommodation performance. The study is limited to radial cutting planes. The effectiveness of a variety of cutting plane geometries was investigated by means of modelling studies conducted on a 45-year human lens. The results obtained from the analyses depend on the particular modelling procedures that are employed. When the lens substance is modelled as an incompressible material, radial cutting planes are found to be ineffective. However, when a poroelastic model is employed for the lens substance, radial cuts are shown to cause an increase in the computed accommodation performance of the lens. In this case, radial cuts made in the peripheral regions of the lens have a relatively small influence on the accommodation performance of the lens; the lentotomy process is seen to be more effective when cuts are made near to the polar axis. When the lens substance is modelled as a poroelastic material, the computational results suggest that useful improvements in lens accommodation performance can be achieved, provided that the radial cuts are extended to the polar axis. Radial cuts are ineffective when the lens substance is modelled as an incompressible material. Significant challenges remain in developing a safe and effective surgical procedure based on this lentotomy technique.

  13. Human eye and the sun hot and cold light

    CERN Document Server

    Vavilov, S I

    1965-01-01

    The Human Eye and the Sun, """"Hot"""" and """"Cold"""" Light is a translation from the Russian language and is a reproduction of texts from Volume IV of S.I. Vavilov, president of the U.S.S.R. Academy of Sciences. The book deals with theoretical and practical developments in lighting techniques. The text gives a brief introduction on the relationship of the human eye and the sun, describing the properties of light, of the sun, and of the human eye. The book describes hot (incandescence) and cold light (luminescence) as coming from different sources. These two types of light are compared. The

  14. DNA methyl transferases are differentially expressed in the human anterior eye segment.

    Science.gov (United States)

    Bonnin, Nicolas; Belville, Corinne; Chiambaretta, Frédéric; Sapin, Vincent; Blanchon, Loïc

    2014-08-01

    DNA methylation is an epigenetic mark involved in the control of genes expression. Abnormal epigenetic events have been reported in human pathologies but weakly documented in eye diseases. The purpose of this study was to establish DNMT mRNA and protein expression levels in the anterior eye segment tissues and their related (primary or immortalized) cell cultures as a first step towards future in vivo and in vitro methylomic studies. Total mRNA was extracted from human cornea, conjunctiva, anterior lens capsule, trabeculum and related cell cultures (cornea epithelial, trabecular meshwork, keratocytes for primary cells; and HCE, Chang, B-3 for immortalized cells). cDNA was quantified by real-time PCR using specific primers for DNMT1, 2, 3A, 3B and 3L. Immunolocalization assays were carried out on human cornea using specific primary antibodies for DNMT1, 2 and 3A, 3B and 3L. All DNMT transcripts were detected in human cornea, conjunctiva, anterior lens capsule, trabeculum and related cells but showed statistically different expression patterns between tissues and cells. DNMT2 protein presented a specific and singular expression pattern in corneal endothelium. This study produced the first inventory of the expression patterns of DNMTs in human adult anterior eye segment. Our research highlights that DNA methylation cannot be ruled out as a way to bring new insights into well-known ocular diseases. In addition, future DNA methylation studies using various cells as experimental models need to be conducted with attention to approach the results analysis from a global tissue perspective. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  15. Human eye localization using the modified Hough transform

    Czech Academy of Sciences Publication Activity Database

    Dobeš, M.; Martínek, J.; Skoupil, D.; Dobešová, Z.; Pospíšil, Jaroslav

    2006-01-01

    Roč. 117, - (2006), s. 468-473 ISSN 0030-4026 Institutional research plan: CEZ:AV0Z10100522 Keywords : human eye localization * modified Hough transform * eye iris and eyelid shape determination Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.585, year: 2006

  16. Relating Eye Activity Measures to Human Controller Remnant Characteristics

    NARCIS (Netherlands)

    Popovici, A; Zaal, P.M.T.; Pool, D.M.; Mulder, M.; Sawaragi, T

    2016-01-01

    This study attempts to partially explain the characteristics of the human perceptual remnant, following Levison’s representation of the remnant as an equivalent observation noise. Eye activity parameters are recorded using an eye tracker in two compensatory tracking tasks in which the visual

  17. Reducing the radiation dose to the eye lens region during CT brain examination: the potential beneficial effect of the combined use of bolus and a bismuth shield

    International Nuclear Information System (INIS)

    Lai, C.W.K.; Chan, T.P.; Cheung, H.Y.; Wong, T.H.

    2015-01-01

    Objective: Computed Tomography (CT) is the leading contributor to medical exposure to ionizing radiation. Although the use of CT brain scans for patients with head injuries and convulsions has shown a tremendous growth, it has raised substantial concerns in the general public because of the risk of radiation-induced cataracts: the current available strategies to reduce the radiation dose to the eye lens region are limited. Therefore, the present research project was initiated with the aim of evaluating the potential benefit of the combined use of bolus and a bismuth shield on reducing the radiation dose to the eye lens region during CT brain examination. Materials and methods: We conducted a series of phantom studies to measure the entrance surface dose (ESD) that is delivered to the eye lens region during CT brain examination under the effect of different scanning and shielding setups. Results: Our results indicated, during CT brain examination: (1) a drastic reduction of 92.5% in the ESD to the eye lens region was found when the CT gantry was tilted from 0 deg. (overall ESD = 30.7 mGy) to 30 deg. cranially (overall ESD = 2.4 mGy), and (2) when the CT gantry was positioned at 0 deg. (the common practice in the clinical setting), the setups with the application of a) a bismuth shield, b) a bismuth shield with a face shield (air gap), c) a bismuth shield with bolus, and d) a bismuth shield with bolus and an air gap can result in an acceptable level of image quality with a smaller overall ESD delivered to the eye lens region (overall ESD = 23.2 mGy, 24 mGy, 21 mGy and 19.9 mGy, respectively) than the setup without the bismuth shield applied (overall ESD = 30.7 mGy). Conclusion: When the primary beam scanning through the eye lens region is unavoidable during CT brain examination, the combined use of a bismuth shield with bolus and a face shield is an easy-to-use and inexpensive shielding setup to reduce the radiation dose delivered to the eye lens region while

  18. Implantation of refractive multifocal intraocular lens with a surface-embedded near section for cataract eyes complicated with a coexisting ocular pathology.

    Science.gov (United States)

    Ouchi, M; Kinoshita, S

    2015-05-01

    To evaluate the postoperative outcomes of cataract eyes complicated with coexisting ocular pathologies that underwent implantation of a refractive multifocal intraocular lens (MIOL) with a surface-embedded near section. LENTIS MPlus (Oculentis GmbH) refractive MIOLs were implanted in 15 eyes with ocular pathologies other than cataract (ie, six high-myopia eyes with an axial length longer than 28 mm, two fundus albipunctatus eyes, two branch retinal-vein occlusion eyes, four glaucoma eyes (one with high myopia), and two keratoconus eyes). Uncorrected or corrected distance and near visual acuity (VA) (UDVA, UNVA, CDVA, and CNVA), contrast sensitivity, and defocus curve were measured at 1 day and 6 months postoperatively, and each patient completed a 6-month postoperative questionnaire regarding vision quality and eyeglass use. Thirteen eyes (87%) registered 0 or better in CDVA and 12 eyes (73%) registered better than 0 in CNVA. Contrast sensitivity in the eyes of all patients was comparable to that of normal healthy subjects. No patient required eyeglasses for distance vision, but three patients (20%) required them for near vision. No patient reported poor or very poor vision quality. With careful case selection, sectorial refractive MIOL implantation is effective for treating cataract eyes complicated with ocular pathologies.

  19. Comparison of axial length, anterior chamber depth and intraocular lens power between IOLMaster and ultrasound in normal, long and short eyes.

    Science.gov (United States)

    Dong, Jing; Zhang, Yaqin; Zhang, Haining; Jia, Zhijie; Zhang, Suhua; Wang, Xiaogang

    2018-01-01

    To compare the axial length (AL), anterior chamber depth (ACD) and intraocular lens power (IOLP) of IOLMaster and Ultrasound in normal, long and short eyes. Seventy-four normal eyes (≥ 22 mm and ≤ 25 mm), 74 long eyes (> 25 mm) and 78 short eyes (devices in the order of IOLMaster followed by Ultrasound. The IOLP were calculated using a free online LADAS IOL formula calculator. The difference in AL and IOLP between IOLMaster and Ultrasound was statistically significant when all three groups were combined. The difference in ACD between IOLMaster and Ultrasound was statistically significant in the normal group (Peye group (Peye group (P = 0.465). For the IOLP difference between IOLMaster and Ultrasound in the normal group, the percentage of IOLP differences eye group, they were 90.5%, 5.4%, 4.1% and 0%, respectively. For the short eye group, they were 61.5%, 23.1%, 10.3%, and 5.1%, respectively. IOLMaster and Ultrasound have statistically significant differences in AL measurements and IOLP (using LADAS formula) for normal, long eye and short eye. The two instruments agree regarding ACD measurements for the long eye group, but differ for the normal and short eye groups. Moreover, the high percentage of IOLP differences greater than |0.5|D in the short eye group is noteworthy.

  20. Human eye colour and HERC2, OCA2 and MATP

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Børsting, Claus; Sanchez, Juan J

    2010-01-01

    Prediction of human eye colour by forensic genetic methods is of great value in certain crime investigations. Strong associations between blue/brown eye colour and the SNP loci rs1129038 and rs12913832 in the HERC2 gene were recently described. Weaker associations between eye colour and other...... genetic markers also exist. In 395 randomly selected Danes, we investigated the predictive values of various combinations of SNP alleles in the HERC2, OCA2 and MATP (SLC45A2) genes and compared the results to the eye colours as they were described by the individuals themselves. The highest predictive...

  1. Stress free configuration of the human eye.

    Science.gov (United States)

    Elsheikh, Ahmed; Whitford, Charles; Hamarashid, Rosti; Kassem, Wael; Joda, Akram; Büchler, Philippe

    2013-02-01

    Numerical simulations of eye globes often rely on topographies that have been measured in vivo using devices such as the Pentacam or OCT. The topographies, which represent the form of the already stressed eye under the existing intraocular pressure, introduce approximations in the analysis. The accuracy of the simulations could be improved if either the stress state of the eye under the effect of intraocular pressure is determined, or the stress-free form of the eye estimated prior to conducting the analysis. This study reviews earlier attempts to address this problem and assesses the performance of an iterative technique proposed by Pandolfi and Holzapfel [1], which is both simple to implement and promises high accuracy in estimating the eye's stress-free form. A parametric study has been conducted and demonstrated reliance of the error level on the level of flexibility of the eye model, especially in the cornea region. However, in all cases considered 3-4 analysis iterations were sufficient to produce a stress-free form with average errors in node location <10(-6)mm and a maximal error <10(-4)mm. This error level, which is similar to what has been achieved with other methods and orders of magnitude lower than the accuracy of current clinical topography systems, justifies the use of the technique as a pre-processing step in ocular numerical simulations. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  2. Implications for Occupational Radiation Protection of the New Dose Limit for the Lens of the Eye. Interim Guidance for Use and Comment

    International Nuclear Information System (INIS)

    2013-12-01

    The IAEA Safety Requirements Safety Standards Series No. GSR Part 3 (Interim), Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards, was approved by the IAEA Board of Governors at its meeting in September 2011 and published in November 2011. The equivalent dose limit for the lens of the eye for occupational exposure in planned exposure situations was reduced from 150 mSv per year to 20 mSv per year, averaged over defined periods of five years, with no annual dose in a single year exceeding 50 mSv. This reduction in the dose limit for the lens of the eye follows the recommendation of the International Commission on Radiological Protection (ICRP) in its statement on tissue reactions on 21 April 2011. At the time when the draft General Safety Requirements (GSR) Part 3 was approved by the Commission on Safety Standards, the Secretariat was asked to develop guidance as early as possible to assist Member States in the observance of the new dose limit. In the longer term, the guidance provided in this TECDOC will form the basis for the consensus guidance in relation to the new dose limit for the lens of the eye that is to be provided in two safety guides currently being developed, Occupational Radiation Protection and Radiation Safety in the Medical Uses of Ionizing Radiation. It is expected that these will be published in 2015-2016. It is recognized that guidance material is required before the two safety guides are finalized in order to give Member States the opportunity to put appropriate actions in place and to plan for the introduction of the new dose limit for the lens of the eye. The purpose of the current publication is to provide advice on the implications for occupational radiation protection of the new dose limit for the lens of the eye and to allow comment on detailed recommendations that may be incorporated into the safety guides

  3. Effects of photobleaching on selected advanced glycation end products in the human lens

    DEFF Research Database (Denmark)

    Holm, Thomas; Raghavan, Cibin T; Nahomi, Rooban

    2015-01-01

    at examining the optical and biochemical effects of the proposed treatment.MethodsHuman donor lenses were photobleaced using a 445 nm cw laser. Lens optical quality was assessed before and after photobleaching by light transmission and scattering. The concentration of the advanced glycation end products (AGEs...... of the photobleaching treatment on lens optical parameters but we could not associate the optical findings to a change in the concentration of the AGEs we measured. This finding suggests that other AGEs were responsible for the observed photobleaching of the human lens after laser treatment. The biochemical nature...

  4. Multiple origin of diurnality in geckos: evidence from eye lens crystallins

    Science.gov (United States)

    Röll, Beate

    2001-05-01

    The large lizard family Gekkonidae comprises about 90 genera (1000 species). While most geckos are nocturnal, the members of about 15 genera are diurnal. All of these species are 'tertiarily' diurnal, i.e. they are descended from 'secondarily' nocturnal ancestors. They have adapted to a diurnal lifestyle in quite different ways, as can be deduced by the crystallin proteins in their lenses. Evaluation of the heterogeneous lens crystallin compositions of diurnal geckos reveals that there are at least three lineages that regained diurnality independently.

  5. Simulation of wave propagation inside a human eye: acoustic eye model (AEM)

    Science.gov (United States)

    Požar, T.; Halilovič, M.; Horvat, D.; Petkovšek, R.

    2018-02-01

    The design and development of the acoustic eye model (AEM) is reported. The model consists of a computer-based simulation that describes the propagation of mechanical disturbance inside a simplified model of a human eye. The capabilities of the model are illustrated with examples, using different laser-induced initial loading conditions in different geometrical configurations typically occurring in ophthalmic medical procedures. The potential of the AEM is to predict the mechanical response of the treated eye tissue in advance, thus complementing other preliminary procedures preceding medical treatments.

  6. A Pseudomonas aeruginosa strain isolated from a contact lens-induced acute red eye (CLARE) is protease-deficient.

    Science.gov (United States)

    Estrellas, P S; Alionte, L G; Hobden, J A

    2000-03-01

    Pseudomonas aeruginosa proteases are thought to be important virulence factors in the pathogenesis of corneal disease. This study examined protease production from two strains of P. aeruginosa responsible for two very distinct clinical diseases: strain Paer1, isolated from a Contact Lens-induced Acute Red Eye (CLARE), and strain KEI 1025, isolated from a corneal ulcer. Strains were compared to a laboratory strain (ATCC 19660) known to produce severe keratitis in experimentally infected mice for protease production and for ocular virulence. Protease production was examined with colorimetric assays, gelatin zymography and western blots. Elastase A activity was quantitated with a staphylolytic assay. Ocular virulence was examined using a mouse scratch model of keratitis. In contrast to strains KEI 1025 or ATCC 19660, Paer1 was unable to produce enzymatically active elastase A, elastase, and protease IV. All three strains produced active alkaline protease. Strains KEI 1025 and ATCC 19660 produced a fulminant keratitis in mice whereas Paer1 produced a mild transient infection. Restoration of elastase activity in Paer1 via genetic complementation did not result in a virulent phenotype. Co-infection of mouse eyes with strains Paer1 and ATCC 19660 resulted in the eventual loss of Paer1 from corneal tissue. These studies suggest that P. aeruginosa elastase A and/or protease IV, but not alkaline protease or elastase, contribute to the ocular virulence of this organism.

  7. Insulin and IGF receptors are developmentally regulated in the chick embry eye lens

    International Nuclear Information System (INIS)

    Bassas, L.; Zelenka, P.S.; Serrano, J.; de Pablo, F.

    1987-01-01

    The authors have previously reported that insulin-like growth factor (IGF) receptors appear to predominate over insulin receptors in early stages of embryogenesis in the chick (days 2-3 whole embryo membranes). Overall, [ 125 I]IGF and II binding to specific receptors was maximal when the rate of brain growth is highest. In the present study they used the embryonic chick lens, a well-defined tissue composed of a single type of cell, to analyze whether changes of insulin and IGFI binding are correlated with changes in growth rate and differentiation state of the cells. They show that both insulin receptors and IGF receptors are present in the lens epithelial cells, and that each type is distinctly regulated throughout development. While there is a direct correlation between IFG-binding capability and growth rate of the cells, there is less relation to differentiation status and embryo age. Insulin receptors, by contrast, appear to be mostly related to the differentiated state of cells, decreasing sharply in fibers, irrespective of their developmental age

  8. Ocular lens availability of glutathione from collagen inserts for protection of eye from radiation

    International Nuclear Information System (INIS)

    Omer, S.A.

    2003-01-01

    Full text: Ocular inserts of glutathione ( G ) were prepared using 1 % collagen solution containing free G ,liposomal G and liposomal G with Concanavalin A ,a specific targeting agent of G to ocular lens. These inserts have to be sterilized for in-vivo ophthalmic application by exposure to U V radiation for 2 hr. using dry ice and acetone for protection of G from thermal degradation. In vitro release characteristics of G (17.0 μ mole) from the prepared inserts were investigated at 37deg C in phosphate buffer pH 7.4 . The results of release data showed that the release of G from inserts were arranged in the following order, free G, liposomal G with or without Concanavalin A. The extent of uptake of G from the collagen inserts by rabbit cornea was also tested. The results of ocular lens availability of G from collagen inserts revealed that a highly significant increase in the uptake of G by ocular lenses,where the percentages drug uptake from the applied doses at T max were 1.12% (p(0.05), 2.12% (p(0.01) and 3.4% (p(0.001) in case of using collagen inserts containing free G, liposomal G and liposomal G with Concanavalin A respectively. That is to say,lipid nature of liposomes together with Concanavlin A improved the penetration of the entrapped hydrophilic G through corneal barrier to the ocular lenses

  9. Mechanism research of miR-181 regulating human lens epithelial cell apoptosis

    Directory of Open Access Journals (Sweden)

    Yu Qin

    2015-05-01

    Full Text Available AIM: To investigate the expression of miR-181 in the lens tissue of cataract and the regulating mechanism of miR-181 on apoptosis of human lens epithelial cell.METHODS:Real time q-PCR was used to measure the expression of miR-181 in the anterior lens capsules of age-related cataract and human lens epithelial cell apoptosis model. miR-181 mimic and inhibitor were transfected using Lipofectamine 2 000 to regulate the expression of miR-181, and then Real time q-PCR was used to verify transfection efficiency. Flow cytometry was used to detect the change of cell apoptosis rate. RESULTS: Compared with control group, the expression of miR-181 was significantly higher in both the anterior lens capsules of age-related cataract and human lens epithelial cell apoptosis model; the relative expression of miR-181 in lens epithelial cells transfected with miR-181 mimic was increased, whereas decreased in cells transfected with miR-181 inhibitor; the apoptosis rate of cells transfected with miR-181 mimic was increased, while reduced in miR-181 inhibitor group. Each result was statistically significant(PCONCLUSION: High expression of miR-181 is detected in anterior lens capsule of age-related cataract. miR-181 might play a certain role in the pathogenesis of cataract via promoting human lens epithelial cell apoptosis. miR-181 probably becomes a new approach for the nonoperative treatment of cataract, but the concrete mechanism still needs to be further studied.

  10. Surface refractive index of the eye lens determined with an optic fiber sensor

    International Nuclear Information System (INIS)

    Pierscionek, B.K.

    1993-01-01

    The use of a fiber optic sensor for measurement of refractive index on the surface of eye lenses is described. The technique makes use of the fact that the amount of light reflected at the interface of two media (Fresnel reflectance) depends on the refractive-index difference between them. The sample is probed with a single-mode fiber, and the refractive index is calculated from the proportion of light reflected at the probe--sample interface

  11. [Effect of UV-radiation on the level of ascorbic acid, SH-groups, and activity of glutathione reductase in the eye lens].

    Science.gov (United States)

    Byshneva, L N; Senchuk, V V

    2002-01-01

    The effect of UV radiation in vitro on the level of ascorbate, SH-groups and glutathione reductase activity in the soluble fraction of bovine eye lens was studied. UV-Irradiation increased NADPH-oxidoreductase activity, the level of ascorbate oxidation and decreased the content of SH-groups and activity of glutathione reductase. Significant activation of the NADPH-oxidoreductase activity in the presence of ascorbate and Cu2+ was observed after UV-irradiation. It is suggested that ascorbate may play an important role in the UV-induced lens pathology.

  12. Human eye colour and HERC2, OCA2 and MATP

    DEFF Research Database (Denmark)

    Mengel-From, Jonas; Børsting, Claus; Sanchez, Juan J.

    2010-01-01

    Prediction of human eye colour by forensic genetic methods is of great value in certain crime investigations. Strong associations between blue/brown eye colour and the SNP loci rs1129038 and rs12913832 in the HERC2 gene were recently described. Weaker associations between eye colour and other...... value of typing either the HERC2 SNPs rs1129038 and/or rs12913832 that are in strong linkage disequilibrium was observed when eye colour was divided into two groups, (1) blue, grey and green (light) and (2) brown and hazel (dark). Sequence variations in rs11636232 and rs7170852 in HERC2, rs1800407...... genetic markers also exist. In 395 randomly selected Danes, we investigated the predictive values of various combinations of SNP alleles in the HERC2, OCA2 and MATP (SLC45A2) genes and compared the results to the eye colours as they were described by the individuals themselves. The highest predictive...

  13. The impact of x-ray tube configuration on the eye lens and extremity doses received by cardiologists in electrophysiology room

    International Nuclear Information System (INIS)

    Domienik, J; Zmyślony, M; Bissinger, A

    2014-01-01

    The aim of the study was to analyse the influence of the x-ray tube configuration on the radiation doses to eye lens and extremities of cardiologists performing pacemaker implantation procedures in electrophysiology laboratory. The measurements were performed on one, widely used, portable C-arm system, first with x-ray tube mounted above the patient table and image intensifier below it and then on a reinstalled (but essentially the same) system with under-table x-ray tube configuration. Thermoluminescent dosimeters, placed in various positions near the eye lens, on the hands and ankle, were used during every procedure. The comparison of doses received by cardiologists after changing the x-ray tube configuration from over- to under-table shows statistically significant dose reduction (p < 0.009) for the eye lens closest to the x-ray tube, left finger, left wrist, while for the ankle a dose increase is observed. The corresponding over- to under-table x-ray tube median dose ratios are 4.1 for the right eye, 4.8 for the left finger, 3.0 for left wrist and, finally, 0.13 for the right ankle. Systems with under-table x-ray tube are preferable from a radiation protection point of view. The observed significant increase in doses to the legs should be partially compensated by the use of a protective lead curtain. (note)

  14. TU-D-209-07: Monte Carlo Assessment of Dose to the Lens of the Eye of Radiologist Using Realistic Phantoms and Eyeglass Models

    Energy Technology Data Exchange (ETDEWEB)

    Xu, X [Rensselaer Polytechnic Inst., Troy, NY (United States); Lin, H [Rensselaer Polytechnic Institute, Troy, NY (United States); Gao, Y; Caracappa, P [RPI, Troy, NY (United States); Wang, Y; Huo, W; Pi, Y; Feng, M; Chen, Z [USTC, Hefei, Anhui (China); Dauer, L [Memorial Sloan-Kettering Cancer Ctr, New York, NY (United States); Thornton, R; Dauer, Z; Alvarado, K [Memorial Sloan Kettering Cancer Center, New York, NY (United States); St Germain, J [Mem Sloan-Kettering Cancer Ctr, New York, NY (United States); Solomon, S [Rensselaer Polytechnic Inst., Troy, NY (United States); USTC, Hefei, Anhui (China)

    2016-06-15

    Purpose: To study how eyeglass design features and postures of the interventional radiologist affect the radiation dose to the lens of the eye. Methods: A mesh-based deformable phantom, consisting of an ultra-fine eye model, was used to simulate postures of a radiologist in fluoroscopically guided interventional procedure (facing the patient, 45 degree to the left, and 45 degree to the right). Various eyewear design features were studied, including the shape, lead-equivalent thickness, and separation from the face. The MCNPX Monte Carlo code was used to simulate the X-ray source used for the transcatheter arterial chemoembolization procedure (The X-ray tube is located 35 cm from the ground, emitting X-rays toward to the ceiling; Field size is 40cm X 40cm; X-ray tube voltage is 90 kVp). Experiments were also performed using dosimeter placed on a physical phantom behind eyeglasses. Results: Without protective eyewear, the radiologist’s eye lens can receive an annual dose equivalent of about 80 mSv. When wearing a pair of lead eyeglasses with lead-equivalent of 0.5-mm Pb, the annual dose equivalent of the eye lens is reduced to 31.47 mSv, but both exceed the new ICRP limit of 20 mSv. A face shield with a lead-equivalent of 0.125-mm Pb in the shape of a semi-cylinder (13cm in radius and 20-cm in height) would further reduce the exposure to the lens of the eye. Examination of postures and eyeglass features reveal surprising information, including that the glass-to-eye separation also plays an important role in the dose to the eye lens from scattered X-ray from underneath and the side. Results are in general agreement with measurements. Conclusion: There is an urgent need to further understand the relationship between the radiation environment and the radiologist’s eyewear and posture in order to provide necessary protection to the interventional radiologists under newly reduced dose limits.

  15. TU-D-209-07: Monte Carlo Assessment of Dose to the Lens of the Eye of Radiologist Using Realistic Phantoms and Eyeglass Models

    International Nuclear Information System (INIS)

    Xu, X; Lin, H; Gao, Y; Caracappa, P; Wang, Y; Huo, W; Pi, Y; Feng, M; Chen, Z; Dauer, L; Thornton, R; Dauer, Z; Alvarado, K; St Germain, J; Solomon, S

    2016-01-01

    Purpose: To study how eyeglass design features and postures of the interventional radiologist affect the radiation dose to the lens of the eye. Methods: A mesh-based deformable phantom, consisting of an ultra-fine eye model, was used to simulate postures of a radiologist in fluoroscopically guided interventional procedure (facing the patient, 45 degree to the left, and 45 degree to the right). Various eyewear design features were studied, including the shape, lead-equivalent thickness, and separation from the face. The MCNPX Monte Carlo code was used to simulate the X-ray source used for the transcatheter arterial chemoembolization procedure (The X-ray tube is located 35 cm from the ground, emitting X-rays toward to the ceiling; Field size is 40cm X 40cm; X-ray tube voltage is 90 kVp). Experiments were also performed using dosimeter placed on a physical phantom behind eyeglasses. Results: Without protective eyewear, the radiologist’s eye lens can receive an annual dose equivalent of about 80 mSv. When wearing a pair of lead eyeglasses with lead-equivalent of 0.5-mm Pb, the annual dose equivalent of the eye lens is reduced to 31.47 mSv, but both exceed the new ICRP limit of 20 mSv. A face shield with a lead-equivalent of 0.125-mm Pb in the shape of a semi-cylinder (13cm in radius and 20-cm in height) would further reduce the exposure to the lens of the eye. Examination of postures and eyeglass features reveal surprising information, including that the glass-to-eye separation also plays an important role in the dose to the eye lens from scattered X-ray from underneath and the side. Results are in general agreement with measurements. Conclusion: There is an urgent need to further understand the relationship between the radiation environment and the radiologist’s eyewear and posture in order to provide necessary protection to the interventional radiologists under newly reduced dose limits.

  16. Near UV radiation effect on the lens and retina

    International Nuclear Information System (INIS)

    Zigman, S.

    1987-01-01

    The discussion presented in this paper indicates that the retina of a diurnal animal with a natural UV-absorbing lens (ie: the gray squirrel) is susceptible to near-UV damage from environmental sources only after the lens has been removed. This suggests that it is very important to protect against near-UV exposure of human eyes after cataract surgery

  17. Proper balance of omega-3 and omega-6 fatty acid supplements with topical cyclosporine attenuated contact lens-related dry eye syndrome.

    Science.gov (United States)

    Wang, Ling; Chen, Xi; Hao, Jingfang; Yang, Lu

    2016-12-01

    Essential fatty acids had been applied in the treatment of dry eye syndrome (DES), but the effects of different combinations of fatty acids have not been investigated. 360 long-term contact lens wearers were included in this double-blinded study. Omega-3 and omega-6 fatty acids were combined in different ratios and supplied to the participants that were randomly divided into six groups, and the effects of different essential fatty acids mixture on DES with or without topical cyclosporine were investigated. More than half of long-term contact lens wearers suffered from DES, which were found to be attenuated by oral supplement of properly balanced O3FA and O6FA fatty acid. The topical cyclosporine treatment considerably inhibited the production of cytokines compared to the cyclosporine negative groups, which further relieved DES. Proper balance of omega-3 and omega-6 fatty acid combination significantly alleviated contact lens-related DES.

  18. Scattered radiation risk to the lens of the eyes for staff involved in using mobile C-arm fluoroscopy unit: Which position is riskiest?

    Energy Technology Data Exchange (ETDEWEB)

    Salleh, H.; Matori, M. K.; Isa, M. J. M. [Agensi Nuklear Malaysia, Bangi, 43000 Kajang, Selangor (Malaysia); Samat, S. B. [Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2015-09-25

    Cataractogenesis is something to be concerned by radiologist and radiographer who work extensively in fluoroscopy. The increasing use of fluoroscopy or interventional fluoroscopy has to come with safety awareness on scattered radiation risk for staff performing the procedure. This study is looking into the radiation risk to the lens of the eyes for staff involved in fluoroscopy using the mobile C-arm fluoroscopy unit. The Toshiba SXT-1000A and Alderson Rando phantom were used in this study. Based on the results, it is found clearly that over couch (OC) procedure is riskier than under couch (UC) procedure. The cathode bound area is clearly riskier than anode bound area especially for UC procedure. More doses (at least +1,568 % of safest position) are received by the lens of the eyes for staff standing at the cathode bound area especially the position opposite to the x-ray tube.

  19. A study of the dose distribution in the region of the eye lens and extremities for staff working in interventional cardiology

    International Nuclear Information System (INIS)

    Domienik, J.; Brodecki, M.; Rusicka, D.

    2012-01-01

    The dose distributions at the region of eye lens and extremities of staff working in interventional cardiology were analyzed. The doses to physicians and nurses from three hospitals in Poland were measured with TL dosimeters (MCP-N) located on various places near eyebrows, on both fingers, wrists, knees and on the ankle. The procedures under investigation were coronary angiography (CA) and percutaneous coronary intervention (PCI), peacemaker and defibrillator implantations (PM/ICDs), cardiac resynchronization therapy with or without defibrillator implantations (CRT-D or CRT) and radiofrequency ablations (RFA). The study aimed at analyzing the distribution of radiation in selected anatomic regions, determining the typical locations of highest doses and estimating the dose ranges for selected types of procedures. The maximum registered doses per procedure to eye lens and ankle were 1.21 mSv and 1.46 mSv for CA PCI procedures, 0.02 mSv and 0.05 mSv for RFA and 0.13 mSv and 0.51 mSv for PM/ICDs, respectively. The maximum doses to fingers, wrists and knees were, accordingly, 2.11 mSv, 1.07 mSv and 0.77 mSv for CA PCI procedures, 0.38 mSv, 0.20 mSv and 0.04 mSv for RFA ones, 0.50 mSv, 0.25 mSv and 0.01 mSv for PM/ICDs procedures and 2.25 mSv, 1.12 mSv and 0.58 mSv for CRT and CRT-D ones. The factors which might influence the dose like utilized radiation, availability of additional protective equipment and position of the staff with respect to X-ray source were also analyzed. The annual doses for eye lens and extremities were estimated on the basis of individual annual workloads of the physicians participating in the study. The highest annual doses were revealed for physicians performing CA PCI procedures. Annual eye lens doses range up to 247 mSv indicating that the occupational limit for eye lens 150 mSv has been surpassed. In case of extremities the maximal estimated annual doses were 355 mSv, 136 mSv, 55 mSv and 328 mSv, for fingers, wrists, knees and for ankle

  20. Scattered radiation risk to the lens of the eyes for staff involved in using mobile C-arm fluoroscopy unit: Which position is riskiest?

    International Nuclear Information System (INIS)

    Salleh, H.; Matori, M. K.; Isa, M. J. M.; Samat, S. B.

    2015-01-01

    Cataractogenesis is something to be concerned by radiologist and radiographer who work extensively in fluoroscopy. The increasing use of fluoroscopy or interventional fluoroscopy has to come with safety awareness on scattered radiation risk for staff performing the procedure. This study is looking into the radiation risk to the lens of the eyes for staff involved in fluoroscopy using the mobile C-arm fluoroscopy unit. The Toshiba SXT-1000A and Alderson Rando phantom were used in this study. Based on the results, it is found clearly that over couch (OC) procedure is riskier than under couch (UC) procedure. The cathode bound area is clearly riskier than anode bound area especially for UC procedure. More doses (at least +1,568 % of safest position) are received by the lens of the eyes for staff standing at the cathode bound area especially the position opposite to the x-ray tube

  1. Vitamin C Degradation Products and Pathways in the Human Lens*

    OpenAIRE

    Nemet, Ina; Monnier, Vincent M.

    2011-01-01

    Vitamin C and its degradation products participate in chemical modifications of proteins in vivo through non-enzymatic glycation (Maillard reaction) and formation of different products called advanced glycation end products. Vitamin C levels are particularly high in selected tissues, such as lens, brain and adrenal gland, and its degradation products can inflict substantial protein damage via formation of advanced glycation end products. However, the pathways of in vivo vitamin C degradation ...

  2. 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 ...

  3. Basement membrane abnormalities in human eyes with diabetic retinopathy

    DEFF Research Database (Denmark)

    Ljubimov, A V; Burgeson, R E; Butkowski, R J

    1996-01-01

    Vascular and parenchymal basement membranes (BMs) are thickened in diabetes, but alterations in individual BM components in diabetic eyes, especially in diabetic retinopathy (DR), are obscure. To identify abnormalities in the distribution of specific constituents, we analyzed cryostat sections...... of human eyes obtained at autopsy (seven normal, five diabetic without DR, and 13 diabetic with DR) by immunofluorescence with antibodies to 30 BM and extracellular matrix components. In non-DR eyes, no qualitative changes of ocular BM components were seen. In some DR corneas, epithelial BM was stained...... discontinuously for laminin-1, entactin/nidogen, and alpha3-alpha4 Type IV collagen, in contrast to non-DR corneas. Major BM alterations were found in DR retinas compared to normals and non-DR diabetics. The inner limiting membrane (retinal BM) of DR eyes had accumulations of fibronectin (including cellular...

  4. Effect of aberrations in human eye on contrast sensitivity function

    Science.gov (United States)

    Quan, Wei; Wang, Feng-lin; Wang, Zhao-qi

    2011-06-01

    The quantitative analysis of the effect of aberrations in human eye on vision has important clinical value in the correction of aberrations. The wave-front aberrations of human eyes were measured with the Hartmann-Shack wave-front sensor and modulation transfer function (MTF) was computed from the wave-front aberrations. Contrast sensitivity function (CSF) was obtained from MTF and the retinal aerial image modulation (AIM). It is shown that the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations deteriorate contrast sensitivity function. When the 2nd, 3rd, 4th, 5th, 6th Zernike aberrations are corrected high contrast sensitivity function can be obtained.

  5. Molecular Diagnosis of Human Taenia martis Eye Infection.

    Science.gov (United States)

    Koch, Till; Schoen, Christoph; Muntau, Birgit; Addo, Marylyn; Ostertag, Helmut; Wiechens, Burkhard; Tappe, Dennis

    2016-05-04

    Taenia martis, a tapeworm harbored in the intestine of mustelids, is a rarely encountered zoonotic cysticercosis pathogen. The larval stage closely resembles the Taenia solium cysticercus, but the natural host and thus the epidemiology of the disease is different. We here report a human eye infection diagnosed molecularly in a previously healthy female German patient. The case represents the third human infection described worldwide; the two previous cases were also European, involving eye and brain. © The American Society of Tropical Medicine and Hygiene.

  6. Histopathologic evaluation of the anterior segment of eyes enucleated due to glaucoma secondary to primary lens displacement in 13 canine globes.

    Science.gov (United States)

    Alario, Anthony F; Pizzirani, Stefano; Pirie, Christopher G

    2013-07-01

    PURPOSE  To describe histologic anterior segment changes in eyes affected with primary lens displacement (PLD) and secondary glaucoma. METHODS  Histologic sections stained with H&E from canine eyes enucleated because of PLD and secondary glaucoma were examined. RESULTS  Thirteen eyes from 12 patients were evaluated. Four dogs were castrated males and eight spayed females. Median age was 8 years of age (range 3-13). Breeds included seven terriers and five other breeds. All eyes examined demonstrated varying degrees of inflammation involving the iris and cleft. Mononuclear and melanophagic infiltration of the cleft was found in all specimens. Four globes also showed polymorphonuclear infiltrate. Pre-iridal fibrovascular membranes were clearly identified in 10 of 13 eyes. Total inflammatory score was significantly greater in all globes examined compared with an age-matched group of normal dogs. The posterior pigmented iris epithelium demonstrated a consistent pattern of hyperplasia and/or hypertrophy and cystic degeneration, more prominent in the more central regions. In some cases, hyperplasia was of greatest severity in the mid-iris and associated with thinning or flattening of the pupillary region. CONCLUSIONS  These results suggest that lens instability may be associated with chronic inflammation and secondary glaucoma. Mechanical irritation from an unstable lens may result in hypertrophy and/or hyperplasia of the posterior pigmented iris epithelium and subsequent cellular exfoliation and release of melanin. An inflammatory reaction directly or indirectly related to melanin release may obstruct the outflow pathways ultimately leading to glaucoma and loss of vision. Use of topical steroids may be warranted in dogs with PLD. © 2012 American College of Veterinary Ophthalmologists.

  7. Age-dependent Fourier model of the shape of the isolated ex vivo human crystalline lens.

    Science.gov (United States)

    Urs, Raksha; Ho, Arthur; Manns, Fabrice; Parel, Jean-Marie

    2010-06-01

    To develop an age-dependent mathematical model of the zero-order shape of the isolated ex vivo human crystalline lens, using one mathematical function, that can be subsequently used to facilitate the development of other models for specific purposes such as optical modeling and analytical and numerical modeling of the lens. Profiles of whole isolated human lenses (n=30) aged 20-69, were measured from shadow-photogrammetric images. The profiles were fit to a 10th-order Fourier series consisting of cosine functions in polar-co-ordinate system that included terms for tilt and decentration. The profiles were corrected using these terms and processed in two ways. In the first, each lens was fit to a 10th-order Fourier series to obtain thickness and diameter, while in the second, all lenses were simultaneously fit to a Fourier series equation that explicitly include linear terms for age to develop an age-dependent mathematical model for the whole lens shape. Thickness and diameter obtained from Fourier series fits exhibited high correlation with manual measurements made from shadow-photogrammetric images. The root-mean-squared-error of the age-dependent fit was 205 microm. The age-dependent equations provide a reliable lens model for ages 20-60 years. The contour of the whole human crystalline lens can be modeled with a Fourier series. Shape obtained from the age-dependent model described in this paper can be used to facilitate the development of other models for specific purposes such as optical modeling and analytical and numerical modeling of the lens. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  8. An analytical method for predicting the geometrical and optical properties of the human lens under accommodation.

    Science.gov (United States)

    Sheil, Conor J; Bahrami, Mehdi; Goncharov, Alexander V

    2014-05-01

    We present an analytical method to describe the accommodative changes in the human crystalline lens. The method is based on the geometry-invariant lens model, in which the gradient-index (GRIN) iso-indicial contours are coupled to the external shape. This feature ensures that any given number of iso-indicial contours does not change with accommodation, which preserves the optical integrity of the GRIN structure. The coupling also enables us to define the GRIN structure if the radii and asphericities of the external lens surfaces are known. As an example, the accommodative changes in lenticular radii and central thickness were taken from the literature, while the asphericities of the external surfaces were derived analytically by adhering to the basic physical conditions of constant lens volume and its axial position. The resulting changes in lens geometry are consistent with experimental data, and the optical properties are in line with expected values for optical power and spherical aberration. The aim of the paper is to provide an anatomically and optically accurate lens model that is valid for 3 mm pupils and can be used as a new tool for better understanding of accommodation.

  9. The effect of gaze angle on the evaluations of SAR and temperature rise in human eye under plane-wave exposures from 0.9 to 10 GHz

    International Nuclear Information System (INIS)

    Diao, Yinliang; Leung, Sai-Wing; Sun, Weinong; Siu, Yun-Ming; Kong, Richard; Hung Chan, Kwok

    2016-01-01

    This article investigates the effect of gaze angle on the specific absorption rate (SAR) and temperature rise in human eye under electromagnetic exposures from 0.9 to 10 GHz. Eye models in different gaze angles are developed based on bio-metric data. The spatial-average SARs in eyes are investigated using the finite-difference time-domain method, and the corresponding maximum temperature rises in lens are calculated by the finite-difference method. It is found that the changes in the gaze angle produce a maximum variation of 35, 12 and 20 % in the eye-averaged SAR, peak 10 g average SAR and temperature rise, respectively. Results also reveal that the eye-averaged SAR is more sensitive to the changes in the gaze angle than peak 10 g average SAR, especially at higher frequencies. (authors)

  10. Human volunteer study with PGME: Eye irritation during vapour exposure

    NARCIS (Netherlands)

    Emmen, H.H.; Muijser, H.; Arts, J.H.E.; Prinsen, M.K.

    2003-01-01

    The objective of this study was to establish the possible occurrence of eye irritation and subjective symptoms in human volunteers exposed to propylene glycol monomethyl ether (PGME) vapour at concentrations of 0, 100 and 150 ppm. Testing was conducted in 12 healthy male volunteers using a repeated

  11. Determination of eye lens doses and identification of risk groups among radiation exposed workers. An Austrian pilot study; Bestimmung der Augenlinsen-Dosis und Identifizierung von Risikogruppen bei beruflich strahlenexponierten Personen. Eine Pilotstudie in Oesterreich

    Energy Technology Data Exchange (ETDEWEB)

    Stadtmann, H.; Hranitzky, C.; Willer, H. [Seibersdorf Labor GmbH, Seibersdorf (Austria). Radiation Protection Dosimetry; Strebl, F.; Ernst, G. [Seibersdorf Labor GmbH, Seibersdorf (Austria). Radiation Safety and Applications; Aspek, W. [Allgemeine Unfallversicherungsanstalt (AUVA), Wien (Austria). Abt. Unfallverhuetung und Berufskrankheitenbekaempfung (HUB)

    2015-07-01

    On European level, in 2014 the dose limit for the lens of the eye of radiation exposed workers has been reduced from 150 to 20 mSv per year (2013/59/Euratom). Data about eye lens exposition measured under realistic operational conditions of Austrian radiation exposed workers is sparse and there is no information to verify, if all professional groups identified to be at risk for elevated eye doses will remain below the new annual dose limit. Therefore, financed by the Austrian Workers Compensation Board, AUVA, a pilot study has been initiated to answer this question. Based on published information professional groups of radiation exposed workers and operational tasks with an enhanced risk of elevated eye lens doses have been identified. By dosimetric measurements with volunteers (forehead dose meters and parallel measurements with whole-body TL-dose meters above and under the lead apron) realistic lens doses will be estimated during selected radiation exposed tasks. Comparison of yielded doses will show whether a TLD outside the apron could serve as an alternative to forehead dose meters dedicated to measure eye lens doses. Measurements with leaded protective eyewear based on IEC61331 yield results for lead equivalent in good agreement with manufacturers' information. Results for eye lens doses determined by use of a RANDO head phantom and a standardized phantom simulating a body in a typical exposition situation for interventional radiologists show that wearing of leaded goggles allows for a 90% dose reduction. Under such conditions the eye lens dose is dominated by backscatter and stray radiation from the operator's head and patient body. This has to be considered for the evaluation of protective effectiveness for leaded eye wear.

  12. Model for screened, charge-regulated electrostatics of an eye lens protein: Bovine gammaB-crystallin

    Science.gov (United States)

    Wahle, Christopher W.; Martini, K. Michael; Hollenbeck, Dawn M.; Langner, Andreas; Ross, David S.; Hamilton, John F.; Thurston, George M.

    2017-09-01

    We model screened, site-specific charge regulation of the eye lens protein bovine gammaB-crystallin (γ B ) and study the probability distributions of its proton occupancy patterns. Using a simplified dielectric model, we solve the linearized Poisson-Boltzmann equation to calculate a 54 ×54 work-of-charging matrix, each entry being the modeled voltage at a given titratable site, due to an elementary charge at another site. The matrix quantifies interactions within patches of sites, including γ B charge pairs. We model intrinsic p K values that would occur hypothetically in the absence of other charges, with use of experimental data on the dependence of p K values on aqueous solution conditions, the dielectric model, and literature values. We use Monte Carlo simulations to calculate a model grand-canonical partition function that incorporates both the work-of-charging and the intrinsic p K values for isolated γ B molecules and we calculate the probabilities of leading proton occupancy configurations, for 4 Debye screening lengths from 6 to 20 Å. We select the interior dielectric value to model γ B titration data. At p H 7.1 and Debye length 6.0 Å, on a given γ B molecule the predicted top occupancy pattern is present nearly 20% of the time, and 90% of the time one or another of the first 100 patterns will be present. Many of these occupancy patterns differ in net charge sign as well as in surface voltage profile. We illustrate how charge pattern probabilities deviate from the multinomial distribution that would result from use of effective p K values alone and estimate the extents to which γ B charge pattern distributions broaden at lower p H and narrow as ionic strength is lowered. These results suggest that for accurate modeling of orientation-dependent γ B -γ B interactions, consideration of numerous pairs of proton occupancy patterns will be needed.

  13. Human rights: eye for cultural diversity

    NARCIS (Netherlands)

    Donders, Y.M.

    2012-01-01

    The relationship and interaction between international human rights law and cultural diversity is a current topic, as is shown by the recent debates in The Netherlands on, for instance, the proposed ban on wearing facial coverage, or burqas, and the proposed ban on ritual slaughter without

  14. Prediction of human eye fixations using symmetry

    NARCIS (Netherlands)

    Kootstra, Gert; Schomaker, Lambert

    2009-01-01

    Humans are very sensitive to symmetry in visual patterns. Reaction time experiments show that symmetry is detected and recognized very rapidly. This suggests that symmetry is a highly salient feature. Existing computational models of saliency, however, have mainly focused on contrast as a measure of

  15. MO-F-CAMPUS-I-04: Patient Eye-Lens Dose Reduction in Routine Brain CT Examinations Using Organ-Based Tube Current Modulation and In-Plane Bismuth Shielding

    International Nuclear Information System (INIS)

    Tsai, Hui-Yu; Liao, Ying-Lan; Lai, Nan-Ku; Chen, Tou-Rong; Chen, Jun-Rong

    2015-01-01

    Purpose: The purpose of this study is to assess eye-lens dose for patients who underwent brain CT examinations using two dose reduction Methods: organ-based tube current modulation (OBTCM) and in-plane bismuth shielding method. Methods: This study received institutional review board approval; written informed consent to participate was obtained from all patients. Ninety patients who underwent the routine brain CT examination were randomly assigned to three groups, ie. routine, OBTCM, and bismuth shield. The OBTCM technique reduced the tube current when the X-ray tube rotates in front of patients’ eye-lens region. The patients in the bismuth shield group were covered one-ply bismuth shield in the eyes’ region. Eye-lens doses were measured using TLD-100H chips and the total effective doses were calculated using CT-Expo according to the CT scanning parameters. The surface doses for patients at off-center positions were assessed to evaluate the off-centering effect. Results: Phantom measurements indicates that OBTCM technique could reduced by 26% to 28% of the surface dose to the eye lens, and increased by 25% of the surface dose at the opposed incident direction at the angle of 180°. Patients’ eye-lens doses were reduced 16.9% and 30.5% dose of bismuth shield scan and OBTCM scan, respectively compared to the routine scan. The eye-lens doses were apparently increased when the table position was lower than isocenter. Conclusion: Reducing the dose to the radiosensitive organs, such as eye lens, during routine brain CT examinations could lower the radiation risks. The OBTCM technique and in-plane bismuth shielding could be used to reduce the eye-lens dose. The eye-lens dose could be effectively reduced using OBTCM scan without interfering the diagnostic image quality. Patient position relative the CT gantry also affects the dose level of the eye lens. This study was supported by the grants from the Ministry of Science and Technology of Taiwan (MOST103-2314-B-182

  16. Aquaporin 0 plays a pivotal role in refractive index gradient development in mammalian eye lens to prevent spherical aberration

    International Nuclear Information System (INIS)

    Kumari, S. Sindhu; Varadaraj, Kulandaiappan

    2014-01-01

    Highlights: • Intact AQP0 functions as fiber cell-to-fiber cell adhesion protein. • AQP0 facilitates reduction in extracellular space and lens water content. • AQP0 adhesion function aids in lens refractive index gradient (RING) formation. • AQP0 prevents lens spherical aberration by establishing RING. • AQP0 is critical for lens transparency and homeostasis. - Abstract: Aquaporin 0 (AQP0) is a transmembrane channel that constitutes ∼45% of the total membrane protein of the fiber cells in mammalian lens. It is critical for lens transparency and homeostasis as mutations and knockout cause autosomal dominant lens cataract. AQP0 functions as a water channel and as a cell-to-cell adhesion (CTCA) molecule in the lens. Our recent in vitro studies showed that the CTCA function of AQP0 could be crucial to establish lens refractive index gradient (RING). However, there is a lack of in vivo data to corroborate the role of AQP0 as a fiber CTCA molecule which is critical for creating lens RING. The present investigation is undertaken to gather in vivo evidence for the involvement of AQP0 in developing lens RING. Lenses of wild type (WT) mouse, AQP0 knockout (heterozygous, AQP0 +/− ) and AQP0 knockout lens transgenically expressing AQP1 (heterozygous AQP0 +/− /AQP1 +/− ) mouse models were used for the study. Data on AQP0 protein profile of intact and N- and/or C-terminal cleaved AQP0 in the lens by MALDI-TOF mass spectrometry and SDS–PAGE revealed that outer cortex fiber cells have only intact AQP0 of ∼28 kDa, inner cortical and outer nuclear fiber cells have both intact and cleaved forms, and inner nuclear fiber cells have only cleaved forms (∼26–24 kDa). Knocking out of 50% of AQP0 protein caused light scattering, spherical aberration (SA) and cataract. Restoring the lost fiber cell membrane water permeability (P f ) by transgene AQP1 did not reinstate complete lens transparency and the mouse lenses showed light scattering and SA. Transmission and

  17. Aquaporin 0 plays a pivotal role in refractive index gradient development in mammalian eye lens to prevent spherical aberration

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, S. Sindhu [Physiology and Biophysics, Stony Brook University, Stony Brook, 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, New York, NY (United States)

    2014-10-03

    Highlights: • Intact AQP0 functions as fiber cell-to-fiber cell adhesion protein. • AQP0 facilitates reduction in extracellular space and lens water content. • AQP0 adhesion function aids in lens refractive index gradient (RING) formation. • AQP0 prevents lens spherical aberration by establishing RING. • AQP0 is critical for lens transparency and homeostasis. - Abstract: Aquaporin 0 (AQP0) is a transmembrane channel that constitutes ∼45% of the total membrane protein of the fiber cells in mammalian lens. It is critical for lens transparency and homeostasis as mutations and knockout cause autosomal dominant lens cataract. AQP0 functions as a water channel and as a cell-to-cell adhesion (CTCA) molecule in the lens. Our recent in vitro studies showed that the CTCA function of AQP0 could be crucial to establish lens refractive index gradient (RING). However, there is a lack of in vivo data to corroborate the role of AQP0 as a fiber CTCA molecule which is critical for creating lens RING. The present investigation is undertaken to gather in vivo evidence for the involvement of AQP0 in developing lens RING. Lenses of wild type (WT) mouse, AQP0 knockout (heterozygous, AQP0{sup +/−}) and AQP0 knockout lens transgenically expressing AQP1 (heterozygous AQP0{sup +/−}/AQP1{sup +/−}) mouse models were used for the study. Data on AQP0 protein profile of intact and N- and/or C-terminal cleaved AQP0 in the lens by MALDI-TOF mass spectrometry and SDS–PAGE revealed that outer cortex fiber cells have only intact AQP0 of ∼28 kDa, inner cortical and outer nuclear fiber cells have both intact and cleaved forms, and inner nuclear fiber cells have only cleaved forms (∼26–24 kDa). Knocking out of 50% of AQP0 protein caused light scattering, spherical aberration (SA) and cataract. Restoring the lost fiber cell membrane water permeability (P{sub f}) by transgene AQP1 did not reinstate complete lens transparency and the mouse lenses showed light scattering and SA

  18. Numerical model of heat transfer in the human eye with consideration of fluid dynamics of the aqueous humour

    Energy Technology Data Exchange (ETDEWEB)

    Karampatzakis, Andreas; Samaras, Theodoros, E-mail: theosama@auth.g [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece)

    2010-10-07

    In this work we present a new 3D numerical model for heat transfer in the human eye, which takes into account the aqueous humour flow in the anterior chamber. We show that consideration of this phenomenon in the calculations alters the temperature distribution on the corneal and lens surfaces, without, however, noticeably changing their absolute values. The most notable effect is that the coolest area of the cornea moves at a point of 2 mm inferior to its geometric centre. The maximum velocity of the fluid in the anterior chamber was found to be 3.36 x 10{sup -4} m s{sup -1}. The effect of the flow on displacing the cool area of the corneal surface temperature is counterbalanced by assuming anisotropic thermal conductivity. The model was implemented in the case of an artificial intraocular lens to show the resulting temperature variations.

  19. Numerical model of heat transfer in the human eye with consideration of fluid dynamics of the aqueous humour.

    Science.gov (United States)

    Karampatzakis, Andreas; Samaras, Theodoros

    2010-10-07

    In this work we present a new 3D numerical model for heat transfer in the human eye, which takes into account the aqueous humour flow in the anterior chamber. We show that consideration of this phenomenon in the calculations alters the temperature distribution on the corneal and lens surfaces, without, however, noticeably changing their absolute values. The most notable effect is that the coolest area of the cornea moves at a point of 2 mm inferior to its geometric centre. The maximum velocity of the fluid in the anterior chamber was found to be 3.36 × 10(-4) m s(-1). The effect of the flow on displacing the cool area of the corneal surface temperature is counterbalanced by assuming anisotropic thermal conductivity. The model was implemented in the case of an artificial intraocular lens to show the resulting temperature variations.

  20. Numerical model of heat transfer in the human eye with consideration of fluid dynamics of the aqueous humour

    International Nuclear Information System (INIS)

    Karampatzakis, Andreas; Samaras, Theodoros

    2010-01-01

    In this work we present a new 3D numerical model for heat transfer in the human eye, which takes into account the aqueous humour flow in the anterior chamber. We show that consideration of this phenomenon in the calculations alters the temperature distribution on the corneal and lens surfaces, without, however, noticeably changing their absolute values. The most notable effect is that the coolest area of the cornea moves at a point of 2 mm inferior to its geometric centre. The maximum velocity of the fluid in the anterior chamber was found to be 3.36 x 10 -4 m s -1 . The effect of the flow on displacing the cool area of the corneal surface temperature is counterbalanced by assuming anisotropic thermal conductivity. The model was implemented in the case of an artificial intraocular lens to show the resulting temperature variations.

  1. Formation of hydroxyl radicals in the human lens is related to the severity of nuclear cataract

    DEFF Research Database (Denmark)

    Garner, B; Davies, Michael Jonathan; Truscott, R J

    2000-01-01

    Recent studies have identified specific hydroxylated amino acid oxidation products which strongly suggest the presence of hydroxyl radical (HO.)-damaged proteins in human cataractous lenses. In the present study, the ability of early stage (type II) and advanced (type IV) nuclear cataractous lens...

  2. The protective effect of resveratrol on human lens epithelial cells against ultraviolet-induced apoptosis

    Directory of Open Access Journals (Sweden)

    Xue - Fang Chen

    2013-06-01

    Full Text Available AIM: To investigate the protective effect of resveratrol on human lens epithelial cells against ultraviolet-induced apoptosis. METHODS:Subcultured human lens epithelial cell line, ultraviolet induced cell apoptosis, 20μmol/L resveratrol pretreated cell, the indicators change was observed: rate of apoptosis was detected by flow cytometry and apoptosis-related factors of caspses-3 and caspase-9 were detected by colorimetric detection, ultrastructure changes were observed under transmission electron microscope. RESULTS: Flow cytometry instrument testing found that resveratrol can suppress the apoptosis induced by ultraviolet irradiation, caspses-3 and caspase-9 content in positive control group were significantly higher than that of the negative control group at the same time period, the difference was statistically significant(P<0.05; caspses-3 and caspase-9 content in experimental group were lower than that in the positive control group at the same time, the difference was statistically significant(P<0.05. In addition, the damage of human lens epithelial cells was alleviated with the incubation time of resveratrol elongated. CONCLUSION:Resveratrol may inhibit ultraviolet-induced apoptosis of human lens epithelial cells, it has preventive function against radioactive cataract, and it can provide reliable evidence for pursuing effective medicine to prevent and treat cataract.

  3. Multiphoton tomography of the human eye

    Science.gov (United States)

    König, Karsten; Batista, Ana; Hager, Tobias; Seitz, Berthold

    2017-02-01

    Multiphoton tomography (MPT) is a novel label-free clinical imaging method for non-invasive tissue imaging with high spatial (300 nm) and temporal (100 ps) resolutions. In vivo optical histology can be realized due to the nonlinear excitation of endogenous fluorophores and second-harmonic generation (SHG) of collagen. Furthermore, optical metabolic imaging (OMI) is performed by two-photon autofluorescence lifetime imaging (FLIM). So far, applications of the multiphoton tomographs DermaInspect and MPTflex were limited to dermatology. Novel applications include intraoperative brain tumor imaging as well as cornea imaging. In this work we describe two-photon imaging of ex vivo human corneas unsuitable for transplantation. Furthermore, the cross-linking (CXL) process of corneal collagen based on UVA exposure and 0.1 % riboflavin was studied. The pharmacokinetics of the photosensitizer could be detected with high spatial resolution. Interestingly, an increase in the stromal autofluorescence intensity and modifications of the autofluorescence lifetimes were observed in the human corneal samples within a few days following CXL.

  4. Molecular restrictions for human eye irritation by chemical vapors

    International Nuclear Information System (INIS)

    Cometto-Muniz, J. Enrique; Cain, William S.; Abraham, Michael H.

    2005-01-01

    Previous research showed a cut-off along homologous volatile organic compounds (VOCs) in their ability to produce acute human mucosal irritation. The present study sought to specify the particular cut-off homolog for sensory eye irritation in an acetate and n-alcohol series. A 1900-ml glass vessel system and a three-alternative forced-choice procedure served to test nonyl, decyl, and dodecyl acetate, and 1-nonanol, 1-decanol, and 1-undecanol. Flowrate to the eye ranged from 2 to 8 L/min and time of exposure from 3 to 24 s. Decyl acetate and 1-undecanol were the shortest homologs that failed to produce eye irritation under all conditions, producing a cut-off effect. Increasing the vapor concentration of decyl acetate and 1-undecanol by 3 and 8 times, respectively, via heating them to 37 deg C made either or both VOCs detectable to only half of the 12 subjects tested, even though the higher vapor concentration was well above a predicted eye irritation threshold. When eye irritation thresholds for homologous acetates and n-alcohols were plotted as a function of the longest unfolded length of the molecule, the values for decyl acetate and 1-undecanol fell within a restricted range of 18 to 19 A. The outcome suggests that the basis for the cut-off is biological, that is, the molecule lacks a key size or structure to trigger transduction, rather than physical, that is, the vapor concentration is too low to precipitate detection

  5. Different schematic eyes and their accuracy to the in vivo eye: a quantitative comparison study

    OpenAIRE

    Almeida, Marina Storani de; Carvalho, Luis Alberto

    2007-01-01

    Current ophthalmic technology allows the manipulation of eye components, such as anterior cornea and lens, of the human eye with a considerable precision and customization. This technology opens up the possibility of exploiting some characteristics of the eye in order to improve the methods of correcting optical aberrations. Moreover, product development and research for the eye-care professional has reached very high standards, since there is nowadays software available to design and simulat...

  6. 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.

  7. [Visual rehabilitation of patients with large post-traumatic defects of the anterior eye segment through iris-lens diaphragm implantation].

    Science.gov (United States)

    Khodzhaev, N S; Sobolev, N P; Mushkova, I A; Izmaylova, S B; Karimova, A N

    The diversity of methodological approaches and lack of pathogenetically reasonable tactics for patients with combined ocular injuries became the basis for the development and systematization of surgical rehabilitation stages of patients, in whom post-traumatic cataract is combined with post-traumatic aniridia and corneal scarring. to construct a visual rehabilitation approach to patients with post-traumatic defects of the anterior eye segment following optical-reconstructive surgery that involved implantation of an iris-lens diaphragm (ILD). We have analyzed 80 reconstructive cases with ILD implantation in patients with post-traumatic aniridia and corneal damage. These patients constituted the first study group (Group 1). We have also investigated 58 eyes with residual ametropy and stable visual function 1 year after ILD implantation before and after conducting a laser keratorefractive surgery. These patients were assigned to the second study group (Group 2). Rehabilitation approach to patients after anterior segment injuries that has been proposed allows to achieve high clinical and functional results and reduce the risk of intra- and postoperative complications. The proposed approach to patients after optical-reconstructive surgery with iris-lens diaphragm implantation followed by keratorefractive surgery is an effective method of visual rehabilitation of anterior eye segment post-traumatic defects.

  8. Radiation-induced cataracts: the Health Protection Agency's response to the ICRP statement on tissue reactions and recommendation on the dose limit for the eye lens.

    Science.gov (United States)

    Bouffler, Simon; Ainsbury, Elizabeth; Gilvin, Phil; Harrison, John

    2012-12-01

    This paper presents the response of the Health Protection Agency (HPA) to the 2011 statement from the International Commission on Radiological Protection (ICRP) on tissue reactions and recommendation of a reduced dose limit for the lens of the eye. The response takes the form of a brief review of the most recent epidemiological and mechanistic evidence. This is presented together with a discussion of dose limits in the context of the related risk and the current status of eye dosimetry, which is relevant for implementation of the limits. It is concluded that although further work is desirable to quantify better the risk at low doses and following protracted exposures, along with research into the mechanistic basis for radiation cataractogenesis to inform selection of risk projection models, the HPA endorses the conclusion reached by the ICRP in their 2011 statement that the equivalent dose limit for the lens of the eye should be reduced from 150 to 20 mSv per year, averaged over a five year period, with no year's dose exceeding 50 mSv.

  9. Expression of c-Fos and c-Jun in the cornea, lens, and retina after ultraviolet irradiation of the rat eye and effect of topical antisense oligodeoxynucleotides

    International Nuclear Information System (INIS)

    Gillardon, F.; Zimmermann, M.

    1995-01-01

    Aims - Immunohistochemical techniques were used to investigate c-Fos and c-Jun proto-oncogene expression in the cornea, lens, and retina after ultraviolet irradiation of the rat eye. Methods -Eyes of anaesthetised rats were exposed to 1.5 J/cm 2 of ultraviolet radiation (280-380 nm). Animals were perfused 1, 6, or 24 hours after irradiation and tissue sections were incubated with specific antiserum to c-Fos and c-Jun, respectively. Non-irradiated contralateral eyes displayed no c-Fos and c-Jun immunoreactivity. One and 6 hours after ultraviolet exposure numerous c-Fos and c-Jun immunopositive nuclei were observed mainly in the epithelial cell layers of the cornea and the lens epithelium. Scattered labelled nuclei were detectable in the retinal ganglion cell layer and the inner nuclear layer. Twenty four hours after irradiation c-Fos and c-Jun protein expression returned to near control levels. Histological signs of ultraviolet damage (for example, chromatin condensation, nuclear fragmentation) were first recognisable in the corneal epithelium 6 hours after irradiation and became more apparent at later times. The rapid and sustained activation of c-Fos and c-Jun expression in the eye after single ultraviolet exposure may represent the molecular mechanism underlying ultraviolet induced photodamage and initiation of cell death. Furthermore, topical application of a c-fos antisense oligode-oxynucleotide to the ultraviolet exposed rat eye inhibited the increase in c-Fos expression in the cornea, suggesting therapeutic activity of antisense drugs in corneal malignant and infectious diseases. (author)

  10. Dosimetric studies of the lens of the eye using a new dosimeter - polls in two departments of Interventional Radiology of the autonomous city of Buenos Aires

    International Nuclear Information System (INIS)

    Pirchio, R.; Sánchez, H.; Domazet, W

    2013-01-01

    During interventional radiology (IR) and cardiology (IC) procedures, medical staff can receive high doses to their eye lenses. The Retrospective Evaluation of Lens Injuries and Dose (RELID) study organized in Argentina in 2010 found incipient opacity in 50% of IC physicians and 41% of IC technicians/nurses. These results, added to the recommendations of the International Commission on Radiological Protection (ICRP), which lowered their former occupational equivalent dose limit for the lens, led us to assess the eye lens dose, Hp(3), during interventional procedures. To this end, a new dosemeter was designed and calibrated at the National Atomic Energy Commission (CNEA) of Argentina to evaluate Hp(3). Personal dose equivalent (Hp(10)), and Hp(3) were assessed for 3 months in two IC and IR departments of Buenos Aires City using thermoluminescent dosimeters (TLD) and electronic personal dosimeter (EPD). An Rando Alderson phantom was used to simulate monthly exposures of five occupational staff members. Hp(3) and Hp(10) were obtained monthly for 14 occupational staff members exposed to 121 IR and IC procedures. We concluded that the annual effective dose and Hp(3) were lower than 0.3 and 10 mSv, respectively. An occupational annual dose constraint of 0.3 mSv was calculated. Average cumulative Hp(3) for working life of 40 years should be lower than 400 and 200 mSv for physicians and technicians/scrub nurse, respectively. Also we concluded that a calibrated EPD worn on a pocket in the lead apron and a TLD dosemeter worn on the collar thyroid (both at the maximal radiation side) could be used as guidance to the lens dose. Finally, To reduce doses of medical staff, actions should be promoted to maximize radiation protection in interventional procedures with appropriate training, using personal dosimetry and protection instruments as lead glasses, ceiling-suspended shields and others. (author)

  11. Safety and efficacy of topical azithromycin ophthalmic solution 1.0% in the treatment of contact lens-related dry eye.

    Science.gov (United States)

    Nichols, Jason J; Bickle, Katherine M; Zink, Richard C; Schiewe, Michael D; Haque, Reza M; Nichols, Kelly K

    2012-03-01

    The purpose of this pilot study was to evaluate the safety and efficacy of azithromycin ophthalmic solution 1% in patients with contact lens-related dry eye (CLDE). This was a 4-week, single-center, open-label clinical trial in patients diagnosed with CLDE using the Contact Lens Dry Eye Questionnaire (CLDEQ). Fifty patients were enrolled in this study. The patients were randomized to 1 of 2 treatment groups: azithromycin ophthalmic solution administered bid on days 1 and 2 and on days 3 to 29±1 or Visine for Contacts rewetting drops administered qid on days 1 to 29±1. The patient diaries were used daily to collect data on comfortable and total contact lens wear time and ocular dryness throughout the treatment period. Tear osmolarity, fluorescein corneal staining, and visual acuity were also assessed during clinic visits. Fifty patients were enrolled, and 44 completed the study. One patient discontinued in the azithromycin group, and five patients discontinued in the rewetting drops group because of adverse events. A statistically significant increase in mean comfortable contact lens wear time from baseline was observed for the subjects treated with azithromycin ophthalmic solution as compared with the subjects treated with rewetting drops at week 4 (P=0.004; primary endpoint), in addition to weeks 2 and 3. The improvement in the mean comfortable wear time for the patients in the azithromycin treatment group exceeded 2 hrs throughout the treatment period (weeks 1-4). No significant differences were observed between the groups for total wear time, low contrast visual acuity, or tear osmolarity. Subject-rated ocular dryness (PM time assessments) was significantly improved from baseline in the subjects treated with azithromycin ophthalmic solution as compared with those treated with rewetting drops at weeks 2 and 3 endpoints (P=0.015 for each week). Additionally, a statistical difference was observed in favor of the azithromycin treatment group at week 2 for the

  12. Region of eye contact of humanoid Nao robot is similar to that of a human

    NARCIS (Netherlands)

    Cuijpers, R.H.; Pol, van der D.; Herrmann, G.; Pearson, M.J.; Lenz, A.; Bremner, P.; Spiers, A.; Leonards, U.

    2013-01-01

    Eye contact is an important social cue in human-human interaction, but it is unclear how easily it carries over to humanoid robots. In this study we investigated whether the tolerance of making eye contact is similar for the Nao robot as compared to human lookers. We measured the region of eye

  13. Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding.

    Science.gov (United States)

    Lin, Ming-Fang; Chen, Chia-Yuen; Lee, Yuan-Hao; Li, Chia-Wei; Gerweck, Leo E; Wang, Hao; Chan, Wing P

    2018-01-01

    Background Multiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification. Purpose To investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging. Material and Methods An anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale. Results The estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shields were used in conjunction with a fixed tube current (22.0% and 35.6% reduction, respectively). Topogram-based TCM mitigated the beam hardening-associated artifacts of bismuth-antimony and barium sulfate shields. This increased the SNR by 21.6% in the extraorbital region and the CNR by 7.2% between the nasal bones and extraorbital regions. The combination of topogram-based TCM and barium sulfate or bismuth-antimony shields reduced lens doses by 12.2% and 27.2%, respectively. Conclusion Image artifacts induced by the bismuth-antimony shield at a fixed tube current for lenticular radioprotection were significantly reduced by topogram-based TCM, which increased the SNR of the anthropomorphic nasal bones and periorbital tissues.

  14. Wavefront sensorless adaptive optics ophthalmoscopy in the human eye

    Science.gov (United States)

    Hofer, Heidi; Sredar, Nripun; Queener, Hope; Li, Chaohong; Porter, Jason

    2011-01-01

    Wavefront sensor noise and fidelity place a fundamental limit on achievable image quality in current adaptive optics ophthalmoscopes. Additionally, the wavefront sensor ‘beacon’ can interfere with visual experiments. We demonstrate real-time (25 Hz), wavefront sensorless adaptive optics imaging in the living human eye with image quality rivaling that of wavefront sensor based control in the same system. A stochastic parallel gradient descent algorithm directly optimized the mean intensity in retinal image frames acquired with a confocal adaptive optics scanning laser ophthalmoscope (AOSLO). When imaging through natural, undilated pupils, both control methods resulted in comparable mean image intensities. However, when imaging through dilated pupils, image intensity was generally higher following wavefront sensor-based control. Despite the typically reduced intensity, image contrast was higher, on average, with sensorless control. Wavefront sensorless control is a viable option for imaging the living human eye and future refinements of this technique may result in even greater optical gains. PMID:21934779

  15. Factors Determining the Oxygen Permeability of Biological Membranes: Oxygen Transport Across Eye Lens Fiber-Cell Plasma Membranes.

    Science.gov (United States)

    Subczynski, Witold Karol; Widomska, Justyna; Mainali, Laxman

    2017-01-01

    Electron paramagnetic resonance (EPR) spin-label oximetry allows the oxygen permeability coefficient to be evaluated across homogeneous lipid bilayer membranes and, in some cases, across coexisting membrane domains without their physical separation. The most pronounced effect on oxygen permeability is observed for cholesterol, which additionally induces the formation of membrane domains. In intact biological membranes, integral proteins induce the formation of boundary and trapped lipid domains with a low oxygen permeability. The effective oxygen permeability coefficient across the intact biological membrane is affected not only by the oxygen permeability coefficients evaluated for each lipid domain but also by the surface area occupied by these domains in the membrane. All these factors observed in fiber cell plasma membranes of clear human eye lenses are reviewed here.

  16. Fast ray-tracing of human eye optics on Graphics Processing Units.

    Science.gov (United States)

    Wei, Qi; Patkar, Saket; Pai, Dinesh K

    2014-05-01

    We present a new technique for simulating retinal image formation by tracing a large number of rays from objects in three dimensions as they pass through the optic apparatus of the eye to objects. Simulating human optics is useful for understanding basic questions of vision science and for studying vision defects and their corrections. Because of the complexity of computing such simulations accurately, most previous efforts used simplified analytical models of the normal eye. This makes them less effective in modeling vision disorders associated with abnormal shapes of the ocular structures which are hard to be precisely represented by analytical surfaces. We have developed a computer simulator that can simulate ocular structures of arbitrary shapes, for instance represented by polygon meshes. Topographic and geometric measurements of the cornea, lens, and retina from keratometer or medical imaging data can be integrated for individualized examination. We utilize parallel processing using modern Graphics Processing Units (GPUs) to efficiently compute retinal images by tracing millions of rays. A stable retinal image can be generated within minutes. We simulated depth-of-field, accommodation, chromatic aberrations, as well as astigmatism and correction. We also show application of the technique in patient specific vision correction by incorporating geometric models of the orbit reconstructed from clinical medical images. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  17. 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

  18. [Expression of thioredoxin-2 in human lens epithelial cells with oxidative damage and its significance].

    Science.gov (United States)

    Che, Xuanyi; Zhao, Qingxia; Li, Di

    2018-03-28

    To explore whether thioredoin-2 (Trx-2) is involved in the development of cataract and to study the effect of Trx-2 on hydrogen peroxide (H2O2)-induced injury in human lens epithelial cells.
 Methods: A total of 10 volunteers (removing the lens due totraumatism) and 30 patients received phacoemulsification (age more than 60 years) were selected. The expression of Trx-2 protein in lens epithelial cells from cataract patients and volunteers were detected by the immunohistochemical streptavidin-peroxidase (SP) method. SRA01/04 cells were cultured and were divided into six groups according to different treatment: a control group, H2O2-treated groups at 20, 50 or 
100 μmol/L, a negative control group (transfected with pCMV6 plasmid plus 100 μmol/L H2O2), and a Trx-2 overexpression group (transfected with pCMV6-Trx-2 plasmid plus 100 μmol/L H2O2). Methyl thiazolyltetrazolium (MTT) assay and flow cytometry was performed to measure the cell viability and apoptosis for SRA01/04 cells, respectively. The activities of superoxide dismutase (SOD) and catalase (CAT), the content of glutathione (GSH) and malondialdehyde (MDA) in human lens epithelial cells were measured via chemical chromatometry. Western blot was used to measure the protein levels of Trx-2, B-cell lymphoma 2 protein (Bcl-2), Bcl-2 associated X protein (Bax) and caspase-3.
 Results: Compared with the volunteers, the expression of Trx-2 was significantly decreased in lens epithelial cells in patients with cataract (PTrx-2 protein in the 20, 50 or 100 μmol/L H2O2 groups was decreased (all PTrx-2 and Bcl-2 expression and up-regulated Bax and caspase-3 expression (all PTrx-2 overexpression group (PTrx-2 and Bcl-2 expression and down-regulated Bax and caspase-3 expression (PTrx-2 might be involved in the apoptosis of lens epithelial cells in patients with cataract. The overexpression of Trx-2 obviously attenuated H2O2-induced injury of human lens epithelial cells, which might be associated with the

  19. ESTIMATION OF MELANIN CONTENT IN IRIS OF HUMAN EYE

    Directory of Open Access Journals (Sweden)

    E. A. Genina

    2008-12-01

    Full Text Available Based on the experimental data obtained in vivo from digital analysis of color images of human irises, the mean melanin content in human eye irises has been estimated. For registration of color images the digital camera Olympus C-5060 has been used. The images have been obtained from irises of healthy volunteers as well as from irises of patients with open-angle glaucoma. The computer program has been developed for digital analysis of the images. The result has been useful for development of novel methods and optimization of already existing ones for non-invasive glaucoma diagnostics.

  20. Constructing a Computer Model of the Human Eye Based on Tissue Slice Images

    OpenAIRE

    Dai, Peishan; Wang, Boliang; Bao, Chunbo; Ju, Ying

    2010-01-01

    Computer simulation of the biomechanical and biological heat transfer in ophthalmology greatly relies on having a reliable computer model of the human eye. This paper proposes a novel method on the construction of a geometric model of the human eye based on tissue slice images. Slice images were obtained from an in vitro Chinese human eye through an embryo specimen processing methods. A level set algorithm was used to extract contour points of eye tissues while a principle component analysi...

  1. Directional asymmetries in human smooth pursuit eye movements.

    Science.gov (United States)

    Ke, Sally R; Lam, Jessica; Pai, Dinesh K; Spering, Miriam

    2013-06-27

    Humans make smooth pursuit eye movements to bring the image of a moving object onto the fovea. Although pursuit accuracy is critical to prevent motion blur, the eye often falls behind the target. Previous studies suggest that pursuit accuracy differs between motion directions. Here, we systematically assess asymmetries in smooth pursuit. In experiment 1, binocular eye movements were recorded while observers (n = 20) tracked a small spot of light moving along one of four cardinal or diagonal axes across a featureless background. We analyzed pursuit latency, acceleration, peak velocity, gain, and catch-up saccade latency, number, and amplitude. In experiment 2 (n = 22), we examined the effects of spatial location and constrained stimulus motion within the upper or lower visual field. Pursuit was significantly faster (higher acceleration, peak velocity, and gain) and smoother (fewer and later catch-up saccades) in response to downward versus upward motion in both the upper and the lower visual fields. Pursuit was also more accurate and smoother in response to horizontal versus vertical motion. CONCLUSIONS. Our study is the first to report a consistent up-down asymmetry in human adults, regardless of visual field. Our findings suggest that pursuit asymmetries are adaptive responses to the requirements of the visual context: preferred motion directions (horizontal and downward) are more critical to our survival than nonpreferred ones.

  2. 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 ( ...

  3. Isoplanatic patch of the human eye for arbitrary wavelengths

    Science.gov (United States)

    Han, Guoqing; Cao, Zhaoliang; Mu, Quanquan; Wang, Yukun; Li, Dayu; Wang, Shaoxin; Xu, Zihao; Wu, Daosheng; Hu, Lifa; Xuan, Li

    2018-03-01

    The isoplanatic patch of the human eye is a key parameter for the adaptive optics system (AOS) designed for retinal imaging. The field of view (FOV) usually sets to the same size as the isoplanatic patch to obtain high resolution images. However, it has only been measured at a specific wavelength. Here we investigate the wavelength dependence of this important parameter. An optical setup is initially designed and established in a laboratory to measure the isoplanatic patch at various wavelengths (655 nm, 730 nm and 808 nm). We established the Navarro wide-angle eye model in Zemax software to further validate our results, which suggested high consistency between the two. The isoplanatic patch as a function of wavelength was obtained within the range of visible to near-infrared, which can be expressed as: θ=0.0028 λ - 0 . 74. This work is beneficial for the AOS design for retinal imaging.

  4. The Digital Future of Humanities through the Lens of DIY Culture

    DEFF Research Database (Denmark)

    Roued-Cunliffe, Henriette

    2017-01-01

    This paper asks the question: Do the humanities by necessity have a digital future? It argues that the answer to this question is both yes and no. The argument looks through the lens of DIY culture as an attempt to try and understand the future for the humanities in terms of both cultural material...... and processes. The argument is made first by examining the case of information sharing within DIY culture as an expression of current day cultural material. Secondly, it illustrated how traditional humanities scholarship, such as reading ancient documents, compares to it’s DIY equivalent within family history...

  5. Comparing Hp(3) evaluated from the conversion coefficients from air kerma to personal dose equivalent for eye lens dosimetry calibrated on a new cylindrical PMMA phantom

    Science.gov (United States)

    Esor, J.; Sudchai, W.; Monthonwattana, S.; Pungkun, V.; Intang, A.

    2017-06-01

    Based on a new occupational dose limit recommended by ICRP (2011), the annual dose limit for the lens of the eye for workers should be reduced from 150 mSv/y to 20 mSv/y averaged over 5 consecutive years in which no single year exceeding 50 mSv. This new dose limit directly affects radiologists and cardiologists whose work involves high radiation exposure over 20 mSv/y. Eye lens dosimetry (Hp(3)) has become increasingly important and should be evaluated directly based on dosimeters that are worn closely to the eye. Normally, Hp(3) dose algorithm was carried out by the combination of Hp(0.07) and Hp(10) values while dosimeters were calibrated on slab PMMA phantom. Recently, there were three reports from European Union that have shown the conversion coefficients from air kerma to Hp(3). These conversion coefficients carried out by ORAMED, PTB and CEA Saclay projects were performed by using a new cylindrical head phantom. In this study, various delivered doses were calculated using those three conversion coefficients while nanoDot, small OSL dosimeters, were used for Hp(3) measurement. These calibrations were performed with a standard X-ray generator at Secondary Standard Dosimetry Laboratory (SSDL). Delivered doses (Hp(3)) using those three conversion coefficients were compared with Hp(3) from nanoDot measurements. The results showed that percentage differences between delivered doses evaluated from the conversion coefficient of each project and Hp(3) doses evaluated from the nanoDots were found to be not exceeding -11.48 %, -8.85 % and -8.85 % for ORAMED, PTB and CEA Saclay project, respectively.

  6. Eye movements reveal epistemic curiosity in human observers.

    Science.gov (United States)

    Baranes, Adrien; Oudeyer, Pierre-Yves; Gottlieb, Jacqueline

    2015-12-01

    Saccadic (rapid) eye movements are primary means by which humans and non-human primates sample visual information. However, while saccadic decisions are intensively investigated in instrumental contexts where saccades guide subsequent actions, it is largely unknown how they may be influenced by curiosity - the intrinsic desire to learn. While saccades are sensitive to visual novelty and visual surprise, no study has examined their relation to epistemic curiosity - interest in symbolic, semantic information. To investigate this question, we tracked the eye movements of human observers while they read trivia questions and, after a brief delay, were visually given the answer. We show that higher curiosity was associated with earlier anticipatory orienting of gaze toward the answer location without changes in other metrics of saccades or fixations, and that these influences were distinct from those produced by variations in confidence and surprise. Across subjects, the enhancement of anticipatory gaze was correlated with measures of trait curiosity from personality questionnaires. Finally, a machine learning algorithm could predict curiosity in a cross-subject manner, relying primarily on statistical features of the gaze position before the answer onset and independently of covariations in confidence or surprise, suggesting potential practical applications for educational technologies, recommender systems and research in cognitive sciences. With this article, we provide full access to the annotated database allowing readers to reproduce the results. Epistemic curiosity produces specific effects on oculomotor anticipation that can be used to read out curiosity states. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Looking at human development through the lens of Christian mission

    Directory of Open Access Journals (Sweden)

    Akinyemi O. Alawode

    2016-10-01

    Full Text Available Approximately one billion people live in extreme poverty, with another two billion people surviving on less than $1 per day. Many of them, living in abject poverty, struggle with ill health, limited access to clean water, hygienic sanitation, poor quality housing, hunger, illiteracy and premature death. However, improving the lives of the poor is a complex undertaking with often little agreement as to how can this be best achieved. The intrinsic goal of development is to advance human dignity, freedom, social equity and self-determination. Moreover, there is no univocal definition of development. In this article my own understanding will be discussed more extensively. My conviction that development, in general in the context of Christian mission, finds its roots in Christian empathy with people in dire need will be stated.

  8. 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

  9. 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.

  10. Visual outcome and changes in corneal endothelial cell density following aphakic iris-fixated intraocular lens implantation in pediatric eyes with subluxated lenses.

    Science.gov (United States)

    Siddiqui, Sorath Noorani; Khan, Ayesha

    2013-01-01

    To evaluate the visual outcome and corneal endothelial cell density after Artisan aphakic intraocular lens (IOL) implantation (Ophtec, Groningen, the Netherlands) in pediatric eyes with subluxated lenses. Artisan aphakic IOLs were implanted in 18 eyes of 11 children with subluxated lenses. Idiopathic subluxations and ectopia lentis due to Marfan syndrome were included, whereas subluxations due to trauma or buphthalmos were excluded. Best-corrected visual acuity (BCVA) and endothelial cell density were monitored. Mean postoperative BCVA and endothelial cell density at last follow-up visit were calculated. The age of children at the time of Artisan aphakic IOL implantation ranged from 8 to 16 years (mean: 11.58 ± 2.9 years). Mean follow-up was 9.12 ± 4.30 months. Mean postoperative logarithm of the minimum angle of resolution BCVA was 0.26 ± 0.13 (P = .001) and mean postoperative endothelial cell density was 2,860 ± 435 cells/mm(2) (P = .000). Mean endothelial cell loss was 17.1%. Artisan aphakic IOL implantation is a safe surgical choice in the management of ectopia lentis in the pediatric age group. It has minimal complications and is less traumatic to pediatric eyes. However, long-term follow-up of these children is required.[J Pediatr Ophthalmol Strabismus 2013;50(3):178-182.]. Copyright 2013, SLACK Incorporated.

  11. 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 ...

  12. 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 ...

  13. 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 ...

  14. Effects of Long-Term Exposure to 60 GHz Millimeter-Wavelength Radiation on the Genotoxicity and Heat Shock Protein (Hsp Expression of Cells Derived from Human Eye

    Directory of Open Access Journals (Sweden)

    Shin Koyama

    2016-08-01

    Full Text Available Human corneal epithelial (HCE-T and human lens epithelial (SRA01/04 cells derived from the human eye were exposed to 60 gigahertz (GHz millimeter-wavelength radiation for 24 h. There was no statistically significant increase in the micronucleus (MN frequency in cells exposed to 60 GHz millimeter-wavelength radiation at 1 mW/cm2 compared with sham-exposed controls and incubator controls. The MN frequency of cells treated with bleomycin for 1 h provided positive controls. The comet assay, used to detect DNA strand breaks, and heat shock protein (Hsp expression also showed no statistically significant effects of exposure. These results indicate that exposure to millimeter-wavelength radiation has no effect on genotoxicity in human eye cells.

  15. A boundary element model for investigating the effects of eye tumor on the temperature distribution inside the human eye.

    Science.gov (United States)

    Ooi, E H; Ang, W T; Ng, E Y K

    2009-08-01

    A three-dimensional boundary element model of the human eye is developed to investigate the thermal effects of eye tumor on the ocular temperature distribution. The human eye is modeled as comprising several regions which have different thermal properties. The tumor is one of these regions. The thermal effects of the tumor are simulated by taking it to have a very high metabolic heat generation and blood perfusion rate. Inside the tumor, the steady state temperature is governed by the Pennes bioheat equation. Elsewhere, in normal tissues of the eye, the temperature satisfies the Laplace's equation. To compute the temperature on the corneal surface, the surface boundary of each region is divided into triangular elements.

  16. Myo/Nog cells: targets for preventing the accumulation of skeletal muscle-like cells in the human lens.

    Directory of Open Access Journals (Sweden)

    Jacquelyn Gerhart

    Full Text Available Posterior capsule opacification (PCO is a vision impairing condition that arises in some patients following cataract surgery. The fibrotic form of PCO is caused by myofibroblasts that may emerge in the lens years after surgery. In the chick embryo lens, myofibroblasts are derived from Myo/Nog cells that are identified by their expression of the skeletal muscle specific transcription factor MyoD, the bone morphogenetic protein inhibitor Noggin, and the epitope recognized by the G8 monoclonal antibody. The goal of this study was to test the hypothesis that depletion of Myo/Nog cells will prevent the accumulation of myofibroblasts in human lens tissue. Myo/Nog cells were present in anterior, equatorial and bow regions of the human lens, cornea and ciliary processes. In anterior lens tissue removed by capsulorhexis, Myo/Nog cells had synthesized myofibroblast and skeletal muscle proteins, including vimentin, MyoD and sarcomeric myosin. Alpha smooth muscle actin (α-SMA was detected in a subpopulation of Myo/Nog cells. Areas of the capsule denuded of epithelial cells were surrounded by Myo/Nog cells. Some of these cell free areas contained a wrinkle in the capsule. Depletion of Myo/Nog cells eliminated cells expressing skeletal muscle proteins in 5-day cultures but did not affect cells immunoreactive for beaded filament proteins that accumulate in differentiating lens epithelial cells. Transforming growth factor-betas 1 and 2 that mediate an epithelial-mesenchymal transition, did not induce the expression of skeletal muscle proteins in lens cells following Myo/Nog cell depletion. This study demonstrates that Myo/Nog cells in anterior lens tissue removed from cataract patients have undergone a partial differentiation to skeletal muscle. Myo/Nog cells appear to be the source of skeletal muscle-like cells in explants of human lens tissue. Targeting Myo/Nog cells with the G8 antibody during cataract surgery may reduce the incidence of PCO.

  17. Comparison of the Retinal Straylight in Pseudophakic Eyes with PMMA, Hydrophobic Acrylic, and Hydrophilic Acrylic Spherical Intraocular Lens

    Directory of Open Access Journals (Sweden)

    Ya-wen Guo

    2014-01-01

    Full Text Available Purpose. To investigate the intraocular straylight value after cataract surgery. Methods. In this study, 76 eyes from 62 patients were subdivided into three groups. A hydrophobic acrylic, a hydrophilic acrylic, and a PMMA IOL were respectively, implanted in 24 eyes, 28 eyes, and 24 eyes. Straylight was measured using C-Quant at 1 week and 1 month postoperatively in natural and dilated pupils. Results. The hydrophilic acrylic IOLs showed significantly lower straylight values than those of the hydrophobic acrylic IOLs in dilated pupils at 1 week and 1 month after surgery (P0.05. Moreover, no significant difference was found in straylight between natural and dilated pupils in each group at 1 week and 1 month postoperatively (P>0.05. Conclusions. Although the hydrophobic acrylic IOL induced more intraocular straylight, straylight differences among the 3 IOLs were minimal. Pupil size showed no effect on intraocular straylight; the intraocular straylight was stable 1 week after surgery.

  18. Comparative Analysis of Gene Expression for Convergent Evolution of Camera Eye Between Octopus and Human

    Science.gov (United States)

    Ogura, Atsushi; Ikeo, Kazuho; Gojobori, Takashi

    2004-01-01

    Although the camera eye of the octopus is very similar to that of humans, phylogenetic and embryological analyses have suggested that their camera eyes have been acquired independently. It has been known as a typical example of convergent evolution. To study the molecular basis of convergent evolution of camera eyes, we conducted a comparative analysis of gene expression in octopus and human camera eyes. We sequenced 16,432 ESTs of the octopus eye, leading to 1052 nonredundant genes that have matches in the protein database. Comparing these 1052 genes with 13,303 already-known ESTs of the human eye, 729 (69.3%) genes were commonly expressed between the human and octopus eyes. On the contrary, when we compared octopus eye ESTs with human connective tissue ESTs, the expression similarity was quite low. To trace the evolutionary changes that are potentially responsible for camera eye formation, we also compared octopus-eye ESTs with the completed genome sequences of other organisms. We found that 1019 out of the 1052 genes had already existed at the common ancestor of bilateria, and 875 genes were conserved between humans and octopuses. It suggests that a larger number of conserved genes and their similar gene expression may be responsible for the convergent evolution of the camera eye. PMID:15289475

  19. Eye safety report 2 (355 nm). Human risk analysis simulator for space lidars

    International Nuclear Information System (INIS)

    Schulmeister, K.; Mellerio, J.; Sonneck, G.

    2001-09-01

    This report contains the results of a risk study for a satellite based lidar mission that uses a laser in the ultraviolet wavelength range to measure atmospheric properties. A lidar can be considered as a laser radar and is an acronym for light detection and ranging. The lidar measures properties of the atmosphere by analysis of laser radiation that is directed back to the lidar. As only part of the laser radiation is scattered or absorbed by the atmosphere, the remaining laser radiation emitted from the spacecraft is incident on the earth's surface, where it might lead to injuries, especially to the eye, if biological thresholds are exceeded. For the analysed mission there is no hazard to the skin, only a potential one to the eye, but only if ocular exposure occurs with very large telescopes. The wavelength of the laser is 355 nm, which is absorbed by the cornea and lens of the eye. That is, it is not focussed onto the retina of the eye as, for instance, visible wavelengths, and therefore comparatively high levels of laser exposure, are needed to produce an injury in the lens and cornea. Because the footprint of the satellite's laser beam on the surface of the earth is so small and it moves so fast, the chance of the naked eye being exposed to the laser is small. Because of the magnification provided by an optical instrument, and the concomitant reduction in the field of view, the probability of exposure of an eye that is using such an instrument decreases with increasing optical power. However, because an increased optical power implies increased diameter of the light gathering optics, the laser energy delivered to an eye increases with instrument size so that if exposure did occur, the probability of delivering energy to the eye that exceeds the thresholds for damage increases. There are thus two conflicting processes at work for viewing with optical instruments: an increase in diameter increases the energy delivered but reduces the probability of lidar beam

  20. Age-related changes in the lateral lipid distribution in a human lens described by mass spectrometry imaging

    Czech Academy of Sciences Publication Activity Database

    Pól, Jaroslav; Faltýsková, Helena; Krásný, Lukáš; Volný, Michael; Vláčil, O.; Hajdúch, M.; Lemr, Karel; Havlíček, Vladimír

    2015-01-01

    Roč. 21, č. 3 (2015), s. 297-303 ISSN 1469-0667 R&D Projects: GA MŠk(CZ) LD13038; GA MŠk LO1509 Grant - others:OPPC(XE) CZ.2.16/3.1.00/24023 Institutional support: RVO:61388971 Keywords : lens * eye * imaging Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.011, year: 2015

  1. 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.

  2. Notes on electropherograms of eye-lens, muscle proteins and zymograms of muscle esterases of fish collected during the first Brazilian expedition to the Antarctica

    Directory of Open Access Journals (Sweden)

    Van Ngan Phan

    1985-01-01

    Full Text Available A preliminary study was carried out on electropherograms of eye-lens, muscle proteins and zymograms of muscle esterases of ten Notothenia larseni, six Notothenia nudifrons and one lanternfish, Electrona antarctica. The fish were collected by the R/V "Prof. W. Besnard" of the Institute of Oceanography, University of São Paulo, during the First Brazilian Expedition to Antarctica. Eye-lens proteins were analysed on cellulose acetate membrane, muscle proteins and esterases on gel of polyaorylamide. Eye-lens proteins showed three types of electropherograms for N. larseni, and two types for N. nudifrons. One of the electropherograms of N. larseni can be readily distinguished from those of N. nudifrons. Electropherograms of muscle proteins of N. larseni and N. nudifrons are very similar and, consist of sixteen to seventeen fractions. Electropherograms of muscle proteins of N. larseni are severely affected by the conservation of the extracts overnight under -20ºC. All N. nudifrons were of the same zymograms of esterases while those of N. larseni varied. Electropherograms of eye-lens and muscle proteins as well as zymograms of esterases of the lanternfish are different from those of nototheniids.Foi realizado um estudo preliminar sobre eletroferogramas de proteínas de cristalino e de músculo esquelético, e zimogramas de esterases de músculo esquelético de dez Notothenia larseni, seis Notothenia nudifrons e de um peixe-lanterna, Electrona antarctica. Os peixes foram coletados pelo N/Oc. "Prof. W. Besnard" do Instituto Oceanográfico da Universidade de São Paulo durante a I Expedição Brasileira à Antártica. As proteinas do cristalino foram analisadas em membranas de acetato de celulose, enquanto que as proteínas e esterases do músculo esquelético, em gel de poliacrilamida. As proteínas do cristalino apresentam três tipos distintos de eletroferogramas para N. larseni, e dois para N. nudifrons. Um dos eletroferogramas de N. larseni, pode ser

  3. UVA photolysis using the protein-bound sensitizers present in human lens

    International Nuclear Information System (INIS)

    Ortwerth, B.J.; Olesen, P.R.

    1994-01-01

    This research was undertaken to demonstrate that the protein-bound chromophores in aged human lens can act as sensitizers for protein damage by UVA light. The water-insoluble (WI) proteins from pooled human and bovine lenses were solubilized by sonication in water and illuminated with UV light similar in output to that transmitted by the cornea. Analysis of the irradiated proteins showed a linear decrease in sulfhydryl groups with a 30% loss after 2 h. No loss was seen when native α-crystallin was irradiated under the same conditions. A 25% loss of histidine residues was also observed with the human lens WI fraction, and sodium dodecyl sulfate polyacrylamide gels indicated considerable protein cross-linking. Similar photodamage was seen with a WI fraction from old bovine lenses. While the data show the presence of UVA sensitizers, some histidine destruction and protein cross-linking were also obtained with α-crystallin and with lysozyme which argue that part of the histidine loss in the human WISS was likely due to tryptophan acting as a sensitizer. (Author)

  4. Effective radiation dose and eye lens dose in dental cone beam CT: effect of field of view and angle of rotation.

    Science.gov (United States)

    Pauwels, R; Zhang, G; Theodorakou, C; Walker, A; Bosmans, H; Jacobs, R; Bogaerts, R; Horner, K

    2014-10-01

    To quantify the effect of field of view (FOV) and angle of rotation on radiation dose in dental cone beam CT (CBCT) and to define a preliminary volume-dose model. Organ and effective doses were estimated using 148 thermoluminescent dosemeters placed in an anthropomorphic phantom. Dose measurements were undertaken on a 3D Accuitomo 170 dental CBCT unit (J. Morita, Kyoto, Japan) using six FOVs as well as full-rotation (360°) and half-rotation (180°) protocols. For the 360° rotation protocols, effective dose ranged between 54 µSv (4 × 4 cm, upper canine) and 303 µSv (17 × 12 cm, maxillofacial). An empirical relationship between FOV dimension and effective dose was derived. The use of a 180° rotation resulted in an average dose reduction of 45% compared with a 360° rotation. Eye lens doses ranged between 95 and 6861 µGy. Significant dose reduction can be achieved by reducing the FOV size, particularly the FOV height, of CBCT examinations to the actual region of interest. In some cases, a 180° rotation can be preferred, as it has the added value of reducing the scan time. Eye lens doses should be reduced by decreasing the height of the FOV rather than using inferior FOV positioning, as the latter would increase the effective dose considerably. The effect of the FOV and rotation angle on the effective dose in dental CBCT was quantified. The dominant effect of FOV height was demonstrated. A preliminary model has been proposed, which could be used to predict effective dose as a function of FOV size and position.

  5. Genetic analyses of the human eye colours using a novel objective method for eye colour classification

    DEFF Research Database (Denmark)

    Andersen, Jeppe D.; Johansen, Peter; Harder, Stine

    2013-01-01

    In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically...... and TYR rs1393350) on the eye colour. We evaluated the two published prediction models for eye colour (IrisPlex [1] and Snipper[2]) and compared the predictions with the PIE-scores. We found good concordance with the prediction from individuals typed as HERC2 rs12913832 G. However, both methods had......-score ranged from −1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE...

  6. Oxygen Tension in the Aqueous Humor of Human Eyes under Different Oxygenation Conditions

    Directory of Open Access Journals (Sweden)

    Farideh Sharifipour

    2013-01-01

    Full Text Available Purpose: To measure oxygen tension in the aqueous humor of human eyes under different oxygenation conditions. Methods: This prospective comparative interventional case series consisted of two parts. In the first part, 120 consecutive patients scheduled for cataract surgery were randomized into group I (control group in which surgery was performed under local anesthesia inhaling 21% oxygen; group II in whom general anesthesia using 50% oxygen was employed; and group III receiving general anesthesia with 100% oxygen. After aspirating 0.2 ml aqueous humor under sterile conditions, the aqueous sample and a simultaneously drawn arterial blood sample were immediately analyzed using a blood gas analyzer. In part II the same procedures were performed in 10 patients after fitting a contact lens and patching the eye for 20 minutes (group IV and in 10 patients after transcorneal delivery of oxygen at a flow rate of 5 L/min (group V. Results: Mean aqueous PO2 in groups I, II and III was 112.3±6.2, 141.1±20.4, and 170.1±27 mmHg, respectively (P values <0.001 and mean arterial PO2 was 85.7±7.9, 184.6±46, and 379.1±75.9 mmHg, respectively (P values <0.001. Aqueous PO2 was 77.2±9.2 mmHg in group IV and 152.3±10.9 mmHg in group V (P values <0.001. There was a significant correlation between aqueous and blood PO2 (r=0.537, P<0.001. The contribution of atmospheric oxygen to aqueous PO2 was 23.7%. Conclusion: Aqueous oxygen tension is mostly dependent on the systemic circulation and in part on the atmosphere. Increasing inspiratory oxygen and transcorneal oxygen delivery both increase aqueous PO2 levels.

  7. A Human Rights Lens on Full Employment and Decent Work in the 2030 Sustainable Development Agenda

    Directory of Open Access Journals (Sweden)

    Diane F. Frey

    2016-06-01

    Full Text Available On September 25, 2015, the United Nations General Assembly adopted the Sustainable Development Goals (SDGs as the blueprint for a global partnership for peace, development, and human rights for the period 2016 to 2030. The 2030 agenda follows on the heels of the Millennium Development Goals (MDGs, adopted in 2001, which set the international development agenda for the period 2001 to 2015. This article uses a human rights lens to demonstrate that the MDGs and the SDGs have not addressed full employment and decent work in a manner that is consistent with the Decent Work Agenda of the International Labour Organization and international human rights legal obligations of the UN member countries. It concludes that the new 2030 development agenda sadly aligns with market-based economic growth strategies rather than the realization of the human rights to full employment and decent work for all.

  8. Can human eyes prevent perceptual narrowing for monkey faces in human infants?

    Science.gov (United States)

    Damon, Fabrice; Bayet, Laurie; Quinn, Paul C; Hillairet de Boisferon, Anne; Méary, David; Dupierrix, Eve; Lee, Kang; Pascalis, Olivier

    2015-07-01

    Perceptual narrowing has been observed in human infants for monkey faces: 6-month-olds can discriminate between them, whereas older infants from 9 months of age display difficulty discriminating between them. The difficulty infants from 9 months have processing monkey faces has not been clearly identified. It could be due to the structural characteristics of monkey faces, particularly the key facial features that differ from human faces. The current study aimed to investigate whether the information conveyed by the eyes is of importance. We examined whether the presence of Caucasian human eyes in monkey faces allows recognition to be maintained in 6-month-olds and facilitates recognition in 9- and 12-month-olds. Our results revealed that the presence of human eyes in monkey faces maintains recognition for those faces at 6 months of age and partially facilitates recognition of those faces at 9 months of age, but not at 12 months of age. The findings are interpreted in the context of perceptual narrowing and suggest that the attenuation of processing of other-species faces is not reversed by the presence of human eyes. © 2015 Wiley Periodicals, Inc.

  9. Human vertical eye movement responses to earth horizontal pitch

    Science.gov (United States)

    Wall, C. 3rd; Petropoulos, A. E.

    1993-01-01

    The vertical eye movements in humans produced in response to head-over-heels constant velocity pitch rotation about a horizontal axis resemble those from other species. At 60 degrees/s these are persistent and tend to have non-reversing slow components that are compensatory to the direction of rotation. In most, but not all subjects, the slow component velocity was well characterized by a rapid build-up followed by an exponential decay to a non-zero baseline. Super-imposed was a cyclic or modulation component whose frequency corresponded to the time for one revolution and whose maximum amplitude occurred during a specific head orientation. All response components (exponential decay, baseline and modulation) were larger during pitch backward compared to pitch forward runs. Decay time constants were shorter during the backward runs, thus, unlike left to right yaw axis rotation, pitch responses display significant asymmetries between paired forward and backward runs.

  10. Noninvasive detection of macular pigments in the human eye.

    Science.gov (United States)

    Gellermann, Werner; Bernstein, Paul S

    2004-01-01

    There is currently strong interest in developing noninvasive technologies for the detection of macular carotenoid pigments in the human eye. These pigments, consisting of lutein and zeaxanthin, are taken up from the diet and are thought to play an important role in the prevention of age-related macular degeneration, the leading cause of blindness in the elderly in the Western world. It may be possible to prevent or delay the onset of this debilitating disease with suitable dietary intervention strategies. We review the most commonly used detection techniques based on heterochromatic flicker photometry, fundus reflectometry, and autofluorescense techniques and put them in perspective with recently developed more molecule-specific Raman detection methods. (c) 2004 Society of Photo-Optical Instrumentation Engineers.

  11. Simultaneous measurement of eye stiffness and contact area for living human eyes.

    Science.gov (United States)

    Kurita, Yuichi; Iida, Yoshichika; Kaneko, Makoto; Mishima, Hiromu K; Katakura, Seiki; Kiuchi, Yoshiaki

    2007-01-01

    Goldmann applanation tonometry is commonly used for measuring IOP (IntraOcular Pressure) to diagnose glaucoma. However, the measured IOP by the applanation tonometry is valid only under the assumption that all the subjects have the same structural eye stiffness. Abnormal eye stiffness makes abnormal corneal deformation and thus the current applanation tonometer misestimates the IOP. This study challenges to measure the eye stiffness in vivo with a non-invasive approach for detecting the abnormal deformation. The deformation of the cornea and the contact area between the probe and the cornea are simultaneously captured by cameras during the experiment. Experimental results show that some subjects have different relationship among the force, the displacement and the contact area even with same IOP. The proposed eye stiffness measurement can help detecting the abnormal deformation and the eyes with misestimated IOP.

  12. Human behavioral biology: commentary on Lerner and von Eye's sociobiology and human development

    NARCIS (Netherlands)

    Molenaar, P.C.M.; Burgess, R.L.

    1993-01-01

    Contends that in their examination of arguments forwarded by sociobiologists to account for key features of human development, R. M. Lerner and A. von Eye (see record 1992-23071-001) misunderstand the role of general theory in science. They also fail to characterize the work of sociobiologists

  13. Viewing Eye Movements During Reading through the Lens of Chaos Theory: How Reading Is Like the Weather

    Science.gov (United States)

    Paulson, Eric J.

    2005-01-01

    This theoretical article examines reading processes using chaos theory as an analogy. Three principles of chaos theory are identified and discussed, then related to reading processes as revealed through eye movement research. Used as an analogy, the chaos theory principle of sensitive dependence contributes to understanding the difficulty in…

  14. Visual Positioning Indoors: Human Eyes vs. Smartphone Cameras.

    Science.gov (United States)

    Wu, Dewen; Chen, Ruizhi; Chen, Liang

    2017-11-16

    Artificial Intelligence (AI) technologies and their related applications are now developing at a rapid pace. Indoor positioning will be one of the core technologies that enable AI applications because people spend 80% of their time indoors. Humans can locate themselves related to a visually well-defined object, e.g., a door, based on their visual observations. Can a smartphone camera do a similar job when it points to an object? In this paper, a visual positioning solution was developed based on a single image captured from a smartphone camera pointing to a well-defined object. The smartphone camera simulates the process of human eyes for the purpose of relatively locating themselves against a well-defined object. Extensive experiments were conducted with five types of smartphones on three different indoor settings, including a meeting room, a library, and a reading room. Experimental results shown that the average positioning accuracy of the solution based on five smartphone cameras is 30.6 cm, while that for the human-observed solution with 300 samples from 10 different people is 73.1 cm.

  15. Changes in spherical aberration after lens refilling with a silicone oil

    NARCIS (Netherlands)

    Wong, Kwok-Hoi; Koopmans, Steven A.; Terwee, Thom; Kooijman, Aart C.

    PURPOSE. It may be possible to restore accommodation to presbyopic human eyes by refilling the lens capsular bag with a soft polymer. In the present study, optical changes were measured that occurred in a pig eye model after the refilling of the capsular bag. METHODS. The optical power and spherical

  16. 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.

  17. 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 ...

  18. Blue eyes in lemurs and humans: same phenotype, different genetic mechanism

    DEFF Research Database (Denmark)

    Bradley, Brenda J; Pedersen, Anja; Mundy, Nicholas I

    2009-01-01

    Almost all mammals have brown or darkly-pigmented eyes (irises), but among primates, there are some prominent blue-eyed exceptions. The blue eyes of some humans and lemurs are a striking example of convergent evolution of a rare phenotype on distant branches of the primate tree. Recent work...... on humans indicates that blue eye color is associated with, and likely caused by, a single nucleotide polymorphism (rs12913832) in an intron of the gene HERC2, which likely regulates expression of the neighboring pigmentation gene OCA2. This raises the immediate question of whether blue eyes in lemurs might...... have a similar genetic basis. We addressed this by sequencing the homologous genetic region in the blue-eyed black lemur (Eulemur macaco flavifrons; N = 4) and the closely-related black lemur (Eulemur macaco macaco; N = 4), which has brown eyes. We then compared a 166-bp segment corresponding...

  19. Computing the stresses and deformations of the human eye components due to a high explosive detonation using fluid-structure interaction model.

    Science.gov (United States)

    Karimi, Alireza; Razaghi, Reza; Navidbakhsh, Mahdi; Sera, Toshihiro; Kudo, Susumu

    2016-05-01

    In spite the fact that a very small human body surface area is comprised by the eye, its wounds due to detonation have recently been dramatically amplified. Although many efforts have been devoted to measure injury of the globe, there is still a lack of knowledge on the injury mechanism due to Primary Blast Wave (PBW). The goal of this study was to determine the stresses and deformations of the human eye components, including the cornea, aqueous, iris, ciliary body, lens, vitreous, retina, sclera, optic nerve, and muscles, attributed to PBW induced by trinitrotoluene (TNT) explosion via a Lagrangian-Eulerian computational coupling model. Magnetic Resonance Imaging (MRI) was employed to establish a Finite Element (FE) model of the human eye according to a normal human eye. The solid components of the eye were modelled as Lagrangian mesh, while an explosive TNT, air domain, and aqueous were modelled using Arbitrary Lagrangian-Eulerian (ALE) mesh. Nonlinear dynamic FE simulations were accomplished using the explicit FE code, namely LS-DYNA. In order to simulate the blast wave generation, propagation, and interaction with the eye, the ALE formulation with Jones-Wilkins-Lee (JWL) equation defining the explosive material were employed. The results revealed a peak stress of 135.70kPa brought about by detonation upsurge on the cornea at the distance of 25cm. The highest von Mises stresses were observed on the sclera (267.3kPa), whereas the lowest one was seen on the vitreous body (0.002kPa). The results also showed a relatively high resultant displacement for the macula as well as a high variation for the radius of curvature for the cornea and lens, which can result in both macular holes, optic nerve damage and, consequently, vision loss. These results may have implications not only for understanding the value of stresses and strains in the human eye components but also giving an outlook about the process of PBW triggers damage to the eye. Copyright © 2016 Elsevier Ltd

  20. 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.

  1. Controlled delivery of antiangiogenic drug to human eye tissue using a MEMS device

    KAUST Repository

    Pirmoradi, Fatemeh Nazly; Ou, Kevin; Jackson, John K.; Letchford, Kevin; Cui, Jing; Wolf, Ki Tae; Graber, Florian; Zhao, Tom; Matsubara, Joanne A.; Burt, Helen; Chiao, Mu; Lin, Liwei

    2013-01-01

    We demonstrate an implantable MEMS drug delivery device to conduct controlled and on-demand, ex vivo drug transport to human eye tissue. Remotely operated drug delivery to human post-mortem eyes was performed via a MEMS device. The developed curved

  2. Recurrent uveitis and pigment dispersion in an eye with in-the-bag acrylic foldable intraocular lens.

    Science.gov (United States)

    Thakur, Monica; Bhatia, Prashant; Chandrasekhar, Garudadri; Senthil, Sirisha

    2016-02-26

    Phacoemulsification with in-the-bag intraocular lens (IOL) implantation is the standard procedure for cataract surgery. Pigment dispersion and uveitis can result when an IOL is placed in the sulcus. We report a case of a 64-year-old woman, with pigmentary glaucoma, who developed recurrent uveitis following uneventful cataract surgery and an in-the-bag hydrophobic acrylic IOL implant. Recurrent uveitis did not subside despite use of topical steroids over 3 months. Dilated examination revealed capsulophimosis with anterior dislocation of the IOL haptic. The mechanical trauma to the iris due to the displaced haptic was implicated as the cause of recurrent uveitis, which completely resolved after capsular excision and IOL repositioning. This case illustrates a rare cause of recurrent uveitis due to IOL haptic dislocation following severe capsulophimosis. 2016 BMJ Publishing Group Ltd.

  3. Eye lens dose estimation during interventional radiology and its impact on the existing radiation protection and safety program: in the context with new International Commission on Radiological Protection guidelines

    International Nuclear Information System (INIS)

    Chaudhari, Suresh

    2014-01-01

    Interventional radiology procedures are used for diagnosing certain medical conditions. The radiologists and medical professionals are exposed to ionizing radiation from X-rays of the equipments and also from scattered radiation during these procedures. The radiation exposure to the eye is more important to be assessed while performing such procedures. ICRP has revised the annual dose limit to the lens of the eye from 150 mSv to 20 mSv. In view of this revision, a study was carried out to evaluate the dose to the lens of the eye during interventional radiology. The paper gives the details of calibration of TLDs using a head phantom, predict annual equivalent dose and also highlight the dependence of dose on the position of TLD on the head. It is observed the predicted annual equivalent doses to the lens of eye are in the range of 25 mGy to 37 mGy. The selection of dosimeter placement may also result in an uncertainty of -14% to 20%. (author)

  4. Different cellular effects of four anti-inflammatory eye drops on human corneal epithelial cells: independent in active components

    OpenAIRE

    Qu, Mingli; Wang, Yao; Yang, Lingling; Zhou, Qingjun

    2011-01-01

    Purpose To evaluate and compare the cellular effects of four commercially available anti-inflammatory eye drops and their active components on human corneal epithelial cells (HCECs) in vitro. Methods The cellular effects of four eye drops (Bromfenac Sodium Hydrate Eye Drops, Pranoprofen Eye Drops, Diclofenac Sodium Eye Drops, and Tobramycin & Dex Eye Drops) and their corresponding active components were evaluated in an HCEC line with five in vitro assays. Cell proliferation and migration were...

  5. Implicit prosody mining based on the human eye image capture technology

    Science.gov (United States)

    Gao, Pei-pei; Liu, Feng

    2013-08-01

    The technology of eye tracker has become the main methods of analyzing the recognition issues in human-computer interaction. Human eye image capture is the key problem of the eye tracking. Based on further research, a new human-computer interaction method introduced to enrich the form of speech synthetic. We propose a method of Implicit Prosody mining based on the human eye image capture technology to extract the parameters from the image of human eyes when reading, control and drive prosody generation in speech synthesis, and establish prosodic model with high simulation accuracy. Duration model is key issues for prosody generation. For the duration model, this paper put forward a new idea for obtaining gaze duration of eyes when reading based on the eye image capture technology, and synchronous controlling this duration and pronunciation duration in speech synthesis. The movement of human eyes during reading is a comprehensive multi-factor interactive process, such as gaze, twitching and backsight. Therefore, how to extract the appropriate information from the image of human eyes need to be considered and the gaze regularity of eyes need to be obtained as references of modeling. Based on the analysis of current three kinds of eye movement control model and the characteristics of the Implicit Prosody reading, relative independence between speech processing system of text and eye movement control system was discussed. It was proved that under the same text familiarity condition, gaze duration of eyes when reading and internal voice pronunciation duration are synchronous. The eye gaze duration model based on the Chinese language level prosodic structure was presented to change previous methods of machine learning and probability forecasting, obtain readers' real internal reading rhythm and to synthesize voice with personalized rhythm. This research will enrich human-computer interactive form, and will be practical significance and application prospect in terms of

  6. 21 CFR 886.5925 - Soft (hydrophilic) contact lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Soft (hydrophilic) contact lens. 886.5925 Section 886.5925 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... against the cornea and adjacent limbal and scleral areas of the eye to correct vision conditions or act as...

  7. 21 CFR 886.5916 - Rigid gas permeable contact lens.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rigid gas permeable contact lens. 886.5916 Section 886.5916 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... against the cornea of the eye to correct vision conditions. The device is made of various materials, such...

  8. Intraocular Telescopic System Design: Optical and Visual Simulation in a Human Eye Model

    OpenAIRE

    Zoulinakis, Georgios; Ferrer-Blasco, Teresa

    2017-01-01

    Purpose. To design an intraocular telescopic system (ITS) for magnifying retinal image and to simulate its optical and visual performance after implantation in a human eye model. Methods. Design and simulation were carried out with a ray-tracing and optical design software. Two different ITS were designed, and their visual performance was simulated using the Liou-Brennan eye model. The difference between the ITS was their lenses’ placement in the eye model and their powers. Ray tracing in bot...

  9. Exposition of the operator's eye lens and efficacy of radiation shielding in fluoroscopically guided interventions; Exposition der Augenlinse des Untersuchers und Effizienz der Strahlenschutzmittel bei fluoroskopischen Interventionen

    Energy Technology Data Exchange (ETDEWEB)

    Galster, M.; Adamus, R. [Klinikum Nuernberg-Nord, Nuernberg (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Guhl, C. [Klinikum Nuernberg (Germany). Inst. fuer Medizinische Physik; Uder, M. [Erlangen Univ. (Germany). Radiologisches Inst.

    2013-05-15

    Purpose: Efficacy of radiation protection tools for the eye lens dose of the radiologist in fluoroscopic interventions. Materials and Methods: A patient phantom was exposed using a fluoroscopic system. Dose measurements were made at the eye location of the radiologist using an ionization chamber. The setting followed typical fluoroscopic interventions. The reduction of scattered radiation by the equipment-mounted shielding (undercouch drapes and overcouch top) was evaluated. The ceiling-suspended lead acrylic glass screen was tested in scattered radiation generated by a slab phantom. The protective properties of different lead glass goggles and lead acrylic visors were evaluated by thermoluminescence measurements on a head phantom in the primary beam. Results: The exposition of the lens of about 110 to 550 {mu}Sv during radiologic interventions is only slightly reduced by the undercouch drapes. Applying the top in addition to the drapes reduces the lens dose by a factor of 2 for PA projections. In 25 LAO the dose is reduced by a factor between 1.2 and 5. The highest doses were measured for AP angulations furthermore the efficacy of the equipment-mounted shielding is minimal. The ceiling-suspended lead screen reduced scatter by a factor of about 30. The lead glass goggles and visors reduced the lens dose up to a factor of 8 to 10. Depending on the specific design, the tested models are less effective especially for radiation from lateral with cranial angulation of the beam. Occasionally the visors even caused an increase of dose. Conclusion: The exposition of the eye lens can be kept below the new occupational limit recommended by the ICRP if the radiation shielding equipment is used consistently. (orig.)

  10. Photodynamic actions of indocyanine green and trypan blue on human lens epithelial cells in vitro.

    Science.gov (United States)

    Melendez, Robert F; Kumar, Neeru; Maswadi, Saher M; Zaslow, Kenneth; Glickmank, Randolph D

    2005-07-01

    The purpose of this study was to evaluate the toxicity and photodynamic activity of indocyanine green (ICG) and trypan blue (TryB) on cultured human lensepithelial cells (LECs). Experimental study. Lens epithelial cell viability was assessed after treatment with ICG and TryB concentrations ranging from 0.025 to 5.0 mg/ml, and exposure to 806 nm diode laser. At ICG concentrations below 0.5 mg/ml, there was > or =75% cell viability; at higher ICG concentrations there was dose-dependent cytotoxicity in addition to loss of cellular viability due to ICG photosensitization. TryB had little cytotoxicity to the LECs: >80% cells were viable irrespective of the dye concentration or laser treatment. These data indicate that ICG may have application as a photosensitizer in the selective eradication of residual LECs after cataract surgery to reduce the incidence of posterior capsule opacification.

  11. Addendum report of the JHPS expert committee on radiation protection of the lens of the eye (2). When and how should the dosimetry of beta H_p(3) be made?

    International Nuclear Information System (INIS)

    Akahane, Keiichi; Tatsuzaki, Hideo; Iimoto, Takeshi; Ichiji, Takeshi; Hamada, Nobuyuki; Iwai, Satoshi; Ohguchi, Hiroyuki; Ohno, Kazuko; Kawaura, Chiyo; Kurosawa, Tadahiro; Tsujimura, Norio; Hayashida, Toshiyuki; Hotta, Yutaka; Yamasaki, Tadashi; Yokoyama, Sumi

    2015-01-01

    In a mixed field of photon and beta radiations, the same dose assigned to skin is normally assigned to the dose to the lens of the eye as a conservative estimate of H_p(3). In exceptional cases where a very high beta dose might be imparted of the same order with the dose limit, however, the conservatively biased dose must be too limiting, and thereby an accurate estimate of beta H_p(3) is desirable. This addendum report of the Japan Health Physics Society Expert Committee on Radiation Protection of the Lens of the Eye presents a practical proposal of when and how the dosimetry of beta H_p(3) should be made. (author)

  12. 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.

  13. Human eye modelling for ophthalmic simulators project for clinic applications

    International Nuclear Information System (INIS)

    Sanchez, Andrea; Santos, Adimir dos; Yoriyaz, Helio

    2002-01-01

    Most of eye tumors are treated by surgical means, which involves the enucleation of affected eyes. In terms of treatment and control of diseases, there is brachytherapy, which often utilizes small applicator of Co-60, I-125, Ru-106, Ir-192, etc. These methods are shown to be very efficient but highly cost. The objective of this work is propose a detailed simulator modelling for eye characterization. Additionally, this study can contribute to design and build a new applicator in order to reduce the cost and to allow more patients to be treated

  14. Human secretory phospholipase A(2), group IB in normal eyes and in eye diseases

    DEFF Research Database (Denmark)

    Kolko, Miriam; Prause, Jan U; Bazan, Nicolas G

    2007-01-01

    , retinitis pigmentosa and glaucoma were evaluated. RESULTS: Expression of hGIB was found in various cells of the eye. The most abundant expression was found in retinal pigment epithelium (RPE) cells, the inner photoreceptor segments, ganglion cells and the corneal endothelium. We explored diseases involving...

  15. 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.

  16. Short wavelength light filtering by the natural human lens and IOLs -- implications for entrainment of circadian rhythm

    DEFF Research Database (Denmark)

    Brøndsted, Adam Elias; Lundeman, Jesper Holm; Kessel, Line

    2013-01-01

    Photoentrainment of circadian rhythm begins with the stimulation of melanopsin containing retinal ganglion cells that respond directly to blue light. With age, the human lens becomes a strong colour filter attenuating transmission of short wavelengths. The purpose of the study was to examine the ...

  17. 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)

  18. Differences in Dry Eye Questionnaire Symptoms in Two Different Modalities of Contact Lens Wear: Silicone-Hydrogel in Daily Wear Basis and Overnight Orthokeratology

    Directory of Open Access Journals (Sweden)

    Nery García-Porta

    2016-01-01

    Full Text Available Purpose. To compare the ocular surface symptoms and signs in an adult population of silicone-hydrogel (Si-Hy contact lens (CL wearers with another modality of CL wear, overnight orthokeratology (OK. Materials and Methods. This was a prospective and comparative study in which 31 myopic subjects were fitted with the same Si-Hy CL and 23 underwent OK treatment for 3 months. Dry eye questionnaire (DEQ was filled in at the beginning of the study and then after 15 days, 1 month, and 3 months using each CL modality. The tear quality was evaluated with noninvasive tear break-up time. Tear production was measured with Schirmer test. Tear samples were collected with Schirmer strips being frozen to analyze the dinucleotide diadenosine tetraphosphate (Ap4A concentration with High-Performance Liquid Chromatography (HPLC. Results. After refitting with ortho-k, a reduction in discomfort and dryness symptoms at the end of the day (p<0.05, χ2 was observed. No significant changes were observed in Ap4A concentration in any group. Bulbar redness, limbal redness, and conjunctival staining increased significantly in the Si-Hy group (p<0.05, Kruskal–Wallis test. Conclusion. Discomfort and dryness symptoms at the end of the day are lower in the OK CL group than in the Si-Hy CL group.

  19. Computational Model-Based Prediction of Human Episodic Memory Performance Based on Eye Movements

    Science.gov (United States)

    Sato, Naoyuki; Yamaguchi, Yoko

    Subjects' episodic memory performance is not simply reflected by eye movements. We use a ‘theta phase coding’ model of the hippocampus to predict subjects' memory performance from their eye movements. Results demonstrate the ability of the model to predict subjects' memory performance. These studies provide a novel approach to computational modeling in the human-machine interface.

  20. Human sensitivity to eye contact in 2D and 3D videoconferencing

    NARCIS (Netherlands)

    Eijk, van R.L.J.; Kuijsters, A.; Dijkstra, K.I.; IJsselsteijn, W.A.

    2010-01-01

    Gaze awareness and eye contact serve important functions in social interaction. In order to maintain those functions in 2D and 3D videoconferencing systems, human sensitivity to eye contact and gaze direction needs to be taken into account in the design of such systems. Here we experimentally

  1. Effects of eye contact and iconic gestures on message retention in human-robot interaction

    NARCIS (Netherlands)

    Dijk, van E.T.; Torta, E.; Cuijpers, R.H.

    2013-01-01

    The effects of iconic gestures and eye contact on message retention in human-robot interaction were investigated in a series of experiments. A humanoid robot gave short verbal messages to participants, accompanied either by iconic gestures or no gestures while making eye contact with the participant

  2. 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

  3. High-speed adaptive optics line scan confocal retinal imaging for human eye.

    Science.gov (United States)

    Lu, Jing; Gu, Boyu; Wang, Xiaolin; Zhang, Yuhua

    2017-01-01

    Continuous and rapid eye movement causes significant intraframe distortion in adaptive optics high resolution retinal imaging. To minimize this artifact, we developed a high speed adaptive optics line scan confocal retinal imaging system. A high speed line camera was employed to acquire retinal image and custom adaptive optics was developed to compensate the wave aberration of the human eye's optics. The spatial resolution and signal to noise ratio were assessed in model eye and in living human eye. The improvement of imaging fidelity was estimated by reduction of intra-frame distortion of retinal images acquired in the living human eyes with frame rates at 30 frames/second (FPS), 100 FPS, and 200 FPS. The device produced retinal image with cellular level resolution at 200 FPS with a digitization of 512×512 pixels/frame in the living human eye. Cone photoreceptors in the central fovea and rod photoreceptors near the fovea were resolved in three human subjects in normal chorioretinal health. Compared with retinal images acquired at 30 FPS, the intra-frame distortion in images taken at 200 FPS was reduced by 50.9% to 79.7%. We demonstrated the feasibility of acquiring high resolution retinal images in the living human eye at a speed that minimizes retinal motion artifact. This device may facilitate research involving subjects with nystagmus or unsteady fixation due to central vision loss.

  4. Imaging shear stress distribution and evaluating the stress concentration factor of the human eye

    Science.gov (United States)

    Joseph Antony, S.

    2015-03-01

    Healthy eyes are vital for a better quality of human life. Historically, for man-made materials, scientists and engineers use stress concentration factors to characterise the effects of structural non-homogeneities on their mechanical strength. However, such information is scarce for the human eye. Here we present the shear stress distribution profiles of a healthy human cornea surface in vivo using photo-stress analysis tomography, which is a non-intrusive and non-X-ray based method. The corneal birefringent retardation measured here is comparable to that of previous studies. Using this, we derive eye stress concentration factors and the directional alignment of major principal stress on the surface of the cornea. Similar to thermometers being used for monitoring the general health in humans, this report provides a foundation to characterise the shear stress carrying capacity of the cornea, and a potential bench mark for validating theoretical modelling of stresses in the human eye in future.

  5. Vergence-mediated changes in the axis of eye rotation during the human vestibulo-ocular reflex can occur independent of eye position.

    Science.gov (United States)

    Migliaccio, Americo A; Cremer, Phillip D; Aw, Swee T; Halmagyi, G Michael; Curthoys, Ian S; Minor, Lloyd B; Todd, Michael J

    2003-07-01

    The aim of this study was to determine whether vergence-mediated changes in the axis of eye rotation in the human vestibulo-ocular reflex (VOR) would obey Listing's Law (normally associated with saccadic eye movements) independent of the initial eye position. We devised a paradigm for disassociating the saccadic velocity axis from eye position by presenting near and far targets that were centered with respect to one eye. We measured binocular 3-dimensional eye movements using search coils in ten normal subjects and 3-dimensional linear head acceleration using Optotrak in seven normal subjects. The stimuli consisted of passive, unpredictable, pitch head rotations with peak acceleration of approximately 2000 degrees /s(2 )and amplitude of approximately 20 degrees. During the pitch head rotation, each subject fixated straight ahead with one eye, whereas the other eye was adducted 4 degrees during far viewing (94 cm) and 25 degrees during near viewing (15 cm). Our data showed expected compensatory pitch rotations in both eyes, and a vergence-mediated horizontal rotation only in the adducting eye. In addition, during near viewing we observed torsional eye rotations not only in the adducting eye but also in the eye looking straight ahead. In the straight-ahead eye, the change in torsional eye velocity between near and far viewing, which began approximately 40 ms after the start of head rotation, was 10+/-6 degrees /s (mean +/- SD). This change in torsional eye velocity resulted in a 2.4+/-1.5 degrees axis tilt toward Listing's plane in that eye. In the adducting eye, the change in torsional eye velocity between near and far viewing was 16+/-6 degrees /s (mean +/- SD) and resulted in a 4.1+/-1.4 degrees axis tilt. The torsional eye velocities were conjugate and both eyes partially obeyed Listing's Law. The axis of eye rotation tilted in the direction of the line of sight by approximately one-third of the angle between the line of sight and a line orthogonal to Listing

  6. EyeFrame: Real-time memory aid improves human multitasking via domain-general eye tracking procedures

    Directory of Open Access Journals (Sweden)

    P. eTaylor

    2015-09-01

    Full Text Available OBJECTIVE: We developed an extensively general closed-loop system to improve human interaction in various multitasking scenarios, with semi-autonomous agents, processes, and robots. BACKGROUND: Much technology is converging toward semi-independent processes with intermittent human supervision distributed over multiple computerized agents. Human operators multitask notoriously poorly, in part due to cognitive load and limited working memory. To multitask optimally, users must remember task order, e.g., the most neglected task, since longer times not monitoring an element indicates greater probability of need for user input. The secondary task of monitoring attention history over multiple spatial tasks requires similar cognitive resources as primary tasks themselves. Humans can not reliably make more than ~2 decisions/s. METHODS: Participants managed a range of 4-10 semi-autonomous agents performing rescue tasks. To optimize monitoring and controlling multiple agents, we created an automated short term memory aid, providing visual cues from users' gaze history. Cues indicated when and where to look next, and were derived from an inverse of eye fixation recency. RESULTS: Contingent eye tracking algorithms drastically improved operator performance, increasing multitasking capacity. The gaze aid reduced biases, and reduced cognitive load, measured by smaller pupil dilation. CONCLUSIONS: Our eye aid likely helped by delegating short-term memory to the computer, and by reducing decision making load. Past studies used eye position for gaze-aware control and interactive updating of displays in application-specific scenarios, but ours is the first to successfully implement domain-general algorithms. Procedures should generalize well to: process control, factory operations, robot control, surveillance, aviation, air traffic control, driving, military, mobile search and rescue, and many tasks where probability of utility is predicted by duration since last

  7. Research progress on the measurement of human lens thickness in vivo

    Directory of Open Access Journals (Sweden)

    Yu-Huan Yang

    2017-05-01

    Full Text Available The precise measurement in lens thickness in vivo, provides great application value for intraocular accommodation and ametropia development mechanism research. And it has great clinical significance for the diagnosis and treatment of glaucoma and cataract. Currently, many ultrasonic methods and optical methods are used in measuring lens thickness. The measurement principles, advantages, disadvantages and the accuracy of the instruments are summarized in this paper. Among these methods, Orbscan II, Pentacam, Lenstar and AS-OCT can be used to measure lens thickness instead of A-scan. More important is the fact that UL-OCT can dynamically monitor the change of the lens thickness with intraocular accommodation. Choosing an instrument with higher measuring accuracy to examine the lens thickness, can provide more accurate and convincing lens thickness data for clinical and scientific research.

  8. Relationship between eye dominance and pattern electroretinograms in normal human subjects.

    Science.gov (United States)

    Kamis, Umit; Gunduz, Kemal; Okudan, Nilsel; Gokbel, Hakki; Bodur, Sait; Tan, Uner

    2005-02-01

    The authors conducted a study in 100 non-smoker healthy normal human subjects to find a relationship between eye dominance and macular function as tested by using transient stimulus and electroretinography. Eye preference procedure was carried out using two reference points and pattern electroretinograms (PERGs) were recorded using black and white checks, each check subtending 23'. Trace averager was retriggered every 300 milliseconds (ms) with data collection time of 150 ms. The difference in PERG P50 amplitudes between right and left eyes was analyzed using Student's t test. There was no significant difference in PERG P50 amplitudes between the right and left eye dominant subjects as well as no significant differences between the right and left eyes in right eye dominants and left eye dominants, but in the left-eye dominant group the left eye PERG P50 amplitudes were significantly higher in females than males. Although pattern-reversal visual evoked potentials of healthy subjects provide electrophysiological evidence of lateralization in the nervous system, sensory eye dominance seems to have no correlation with macular function.

  9. A class I (Senofilcon A) soft contact lens prevents UVB-induced ocular effects, including cataract, in the rabbit in vivo.

    Science.gov (United States)

    Giblin, Frank J; Lin, Li-Ren; Leverenz, Victor R; Dang, Loan

    2011-06-01

    UVB radiation from sunlight is known to be a risk factor for human cataract. The purpose in this study was to investigate the ability of a class I UV-blocking soft contact lens to protect against UVB-induced effects on the ocular tissues of the rabbit in vivo. Eyes of rabbits were exposed to UVB light for 30 minutes (270-360 nm, peak at 310 nm, 1.7 mW/cm(2) on the cornea). Eyes were irradiated in the presence of either a UV-blocking senofilcon A contact lens, a minimally UV-blocking lotrafilcon A contact lens, or no contact lens at all. Effects on the cornea and lens were evaluated at various times after exposure. Eyes irradiated with no contact lens protection showed corneal epithelial cell loss plus lens epithelial cell swelling, vacuole formation, and DNA single-strand breaks, as well as lens anterior subcapsular opacification. The senofilcon A lens protected nearly completely against the UVB-induced effects, whereas the lotrafilcon A lens showed no protection. The results indicate that use of a senofilcon A contact lens is beneficial in protecting ocular tissues of the rabbit against the harmful effects of UVB light, including photokeratitis and cataract.

  10. simEye: computer-based simulation of visual perception under various eye defects using Zernike polynomials

    OpenAIRE

    Fink, Wolfgang; Micol, Daniel

    2006-01-01

    We describe a computer eye model that allows for aspheric surfaces and a three-dimensional computer-based ray-tracing technique to simulate optical properties of the human eye and visual perception under various eye defects. Eye surfaces, such as the cornea, eye lens, and retina, are modeled or approximated by a set of Zernike polynomials that are fitted to input data for the respective surfaces. A ray-tracing procedure propagates light rays using Snell’s law of refraction from an input objec...

  11. Proton absorbed dose distribution in human eye simulated by SRNA-2KG code

    International Nuclear Information System (INIS)

    Ilic, R. D.; Pavlovic, R.

    2004-01-01

    The model of Monte Carlo SRNA code is described together with some numerical experiments to show feasibility of this code to be used in proton therapy, especially for tree dimensional proton absorption dose calculation in human eye. (author) [sr

  12. Pharmacokinetics of bevacizumab after topical and intravitreal administration in human eyes

    OpenAIRE

    Moisseiev, Elad; Waisbourd, Michael; Ben-Artsi, Elad; Levinger, Eliya; Barak, Adiel; Daniels, Tad; Csaky, Karl; Loewenstein, Anat; Barequet, Irina S.

    2013-01-01

    Background Topical bevacizumab is a potential treatment modality for corneal neovascularization, and several recent studies have demonstrated its efficacy. No previous study of the pharmacokinetics of topical bevacizumab has been performed in human eyes. The purpose of this study is to investigate the pharmacokinetics of topical administration of bevacizumab in human eyes, and also to compare the pharmacokinetics of intravitreal bevacizumab injections with previously reported data. Methods Tw...

  13. A computational model of blast loading on the human eye.

    Science.gov (United States)

    Bhardwaj, Rajneesh; Ziegler, Kimberly; Seo, Jung Hee; Ramesh, K T; Nguyen, Thao D

    2014-01-01

    Ocular injuries from blast have increased in recent wars, but the injury mechanism associated with the primary blast wave is unknown. We employ a three-dimensional fluid-structure interaction computational model to understand the stresses and deformations incurred by the globe due to blast overpressure. Our numerical results demonstrate that the blast wave reflections off the facial features around the eye increase the pressure loading on and around the eye. The blast wave produces asymmetric loading on the eye, which causes globe distortion. The deformation response of the globe under blast loading was evaluated, and regions of high stresses and strains inside the globe were identified. Our numerical results show that the blast loading results in globe distortion and large deviatoric stresses in the sclera. These large deviatoric stresses may be indicator for the risk of interfacial failure between the tissues of the sclera and the orbit.

  14. A new human eye model for ophthalmic brachytherapy dosimetry

    International Nuclear Information System (INIS)

    Yoriyaz, H.; Sanchez, A.; Dos Santos, A.

    2005-01-01

    The present work proposes a new mathematical eye model for ophthalmic brachytherapy dosimetry. This new model includes detailed description of internal structures that were not treated in previous works, allowing dose determination in different regions of the eye for a more adequate clinical analysis. Dose calculations were determined with the MCNP-4C Monte Carlo particle transport code running n parallel environment using PVM. The Amersham CKA4 ophthalmic applicator has been chosen and the depth dose distribution has been determined and compared to those provide by the manufacturer. The results have shown excellent agreement. Besides, absorbed dose values due to both 125 I seeds and 60 Co plaques were obtained for each one of the different structures which compose the eye model and can give relevant information in eventual clinical analyses. (authors)

  15. Measuring Human Performance in Simulated Nuclear Power Plant Control Rooms Using Eye Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Kovesdi, Casey Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rice, Brandon Charles [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bower, Gordon Ross [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spielman, Zachary Alexander [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hill, Rachael Ann [Idaho National Lab. (INL), Idaho Falls, ID (United States); LeBlanc, Katya Lee [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-11-01

    Control room modernization will be an important part of life extension for the existing light water reactor fleet. As part of modernization efforts, personnel will need to gain a full understanding of how control room technologies affect performance of human operators. Recent advances in technology enables the use of eye tracking technology to continuously measure an operator’s eye movement, which correlates with a variety of human performance constructs such as situation awareness and workload. This report describes eye tracking metrics in the context of how they will be used in nuclear power plant control room simulator studies.

  16. Measuring Human Performance in Simulated Nuclear Power Plant Control Rooms Using Eye Tracking

    International Nuclear Information System (INIS)

    Kovesdi, Casey Robert; Rice, Brandon Charles; Bower, Gordon Ross; Spielman, Zachary Alexander; Hill, Rachael Ann; LeBlanc, Katya Lee

    2015-01-01

    Control room modernization will be an important part of life extension for the existing light water reactor fleet. As part of modernization efforts, personnel will need to gain a full understanding of how control room technologies affect performance of human operators. Recent advances in technology enables the use of eye tracking technology to continuously measure an operator's eye movement, which correlates with a variety of human performance constructs such as situation awareness and workload. This report describes eye tracking metrics in the context of how they will be used in nuclear power plant control room simulator studies.

  17. Dynamical models of the human eye and strabismus

    International Nuclear Information System (INIS)

    Pascolo, P.; Carniel, R.; Grimaz, S.

    2009-01-01

    In this work, the applicability of a recently published dynamical model of the eye to the case of strabismus is investigated. Although the basic scheme of the original model remains valid, the simulation of the pathological dynamics requires a more suitable coverage of the space of the physiological rotations of the eye. This requisite is reached by developing the original model and by taking into account the contributions of connective tissues that were originally neglected. Possible wider fields of application of the model are then discussed.

  18. Human Commercial Models' Eye Colour Shows Negative Frequency-Dependent Selection.

    Directory of Open Access Journals (Sweden)

    Isabela Rodrigues Nogueira Forti

    Full Text Available In this study we investigated the eye colour of human commercial models registered in the UK (400 female and 400 male and Brazil (400 female and 400 male to test the hypothesis that model eye colour frequency was the result of negative frequency-dependent selection. The eye colours of the models were classified as: blue, brown or intermediate. Chi-square analyses of data for countries separated by sex showed that in the United Kingdom brown eyes and intermediate colours were significantly more frequent than expected in comparison to the general United Kingdom population (P<0.001. In Brazil, the most frequent eye colour brown was significantly less frequent than expected in comparison to the general Brazilian population. These results support the hypothesis that model eye colour is the result of negative frequency-dependent selection. This could be the result of people using eye colour as a marker of genetic diversity and finding rarer eye colours more attractive because of the potential advantage more genetically diverse offspring that could result from such a choice. Eye colour may be important because in comparison to many other physical traits (e.g., hair colour it is hard to modify, hide or disguise, and it is highly polymorphic.

  19. Eye Detection and Tracking for Intelligent Human Computer Interaction

    National Research Council Canada - National Science Library

    Yin, Lijun

    2006-01-01

    .... In this project, Dr. Lijun Yin has developed a new algorithm for detecting and tracking eyes under an unconstrained environment using a single ordinary camera or webcam. The new algorithm is advantageous in that it works in a non-intrusive way based on a socalled Topographic Context approach.

  20. Objective measurement of postocclusion surge during phacoemulsification in human eye-bank eyes.

    Science.gov (United States)

    Georgescu, Dan; Payne, Marielle; Olson, Randall J

    2007-03-01

    To objectively compare the postocclusion vacuum surge among different phacoemulsification machines and devices. Experimental study. Infiniti, Legacy, Millennium, and Sovereign were tested in an eye-bank eye. All the machines were tested with 20-gauge non-ABS tips, 430 mm Hg vacuum pressure, 24 ml/minute aspiration rate, peristaltic pump, and 75 cm bottle height. In addition, Infiniti and Legacy were also tested with 20-gauge bypass tips (ABS), 125 cm bottle height, and 40 ml/minute flow rate. We also tested 19-gauge tips with Infiniti and Sovereign and the venturi pump for Millennium. Significant differences were found between all the machines tested with Millennium peristaltic generating the least and Millennium Venturi the most surge. ABS tips significantly decreased the surge for Legacy but not for Infiniti. Cruise Control (CC) had a significant effect on Sovereign but not on Millennium. Increasing the bottle height decreased surge while increasing the flow increased surge for both Infiniti and Legacy. The 19-gauge tips increased surge for both Infiniti and Sovereign. Surge varied over a range of 40 microm to more than 2 mm. ABS and CC decrease surge, especially when the machine is not functioning near the limits of surge prevention. Certain parameters, such as a 19-gauge tip and high flow, dramatically increased surge, whereas elevating the bottle ameliorates it. Understanding the impact of all these features will help in minimizing the problem.

  1. Image system analysis of human eye wave-front aberration on the basis of HSS

    Science.gov (United States)

    Xu, Ancheng

    2017-07-01

    Hartmann-Shack sensor (HSS) has been used in objective measurement of human eye wave-front aberration, but the research on the effects of sampling point size on the accuracy of the result has not been reported. In this paper, point spread function (PSF) of the whole system mathematical model was obtained via measuring the optical imaging system structure of human eye wave-front aberration measurement. The impact of Airy spot size on the accuracy of system was analyzed. Statistics study show that the geometry of Airy spot size of the ideal light source sent from eye retina formed on the surface of HSS is far smaller than the size of the HSS sample point image used in the experiment. Therefore, the effect of Airy spot on the precision of the system can be ignored. This study theoretically and experimentally justifies the reliability and accuracy of human eye wave-front aberration measurement based on HSS.

  2. Eye trauma

    African Journals Online (AJOL)

    2011-02-02

    Feb 2, 2011 ... Note your findings in an orderly fashion: orbit, lids, conjunctiva, cornea, anterior chamber, iris, pupil reaction, lens, fundus. • Stain cornea with fluorescein. It is advisable to examine the eye as soon as possible since a delay will invariably lead to lid swelling, making the examination far more difficult. This can ...

  3. Cross-linking of lens crystallin proteins induced by tryptophan metabolites and metal ions

    DEFF Research Database (Denmark)

    Tweeddale, Helen J; Hawkins, Clare Louise; Janmie, Joane F

    2016-01-01

    Long-wavelength solar UV radiation is implicated in photodamage to the human eye. The human lens contains multiple tryptophan-derived compounds that have significant absorbance bands in the UVA region (λ 315-400 nm) that act as efficient physical filters for these wavelengths. The concentrations...

  4. Establishment of detailed eye model of adult chinese male and dose conversion coefficients calculation under neutron exposure

    International Nuclear Information System (INIS)

    Zhu, Hongyu; Qiu, Rui; Ren, Li; Zhang, Hui; Li, Junli; Wu, Zhen; Li, Chunyan

    2017-01-01

    The human eye lens is sensitive to radiation. ICRP-118 publication recommended a reduction of the occupational annual equivalent dose limit from 150 to 20 mSv, averaged over defined periods of 5 y. Therefore, it is very important to build a detailed eye model for the accurate dose assessment and radiation risk evaluation of eye lens. In this work, a detailed eye model was build based on the characteristic anatomic parameters of the Chinese adult male. This eye model includes seven main structures, which are scleral, choroid, lens, iris, cornea, vitreous body and aqueous humor. The lens was divided into sensitive volume and insensitive volume based on different cell populations. The detailed eye model was incorporated into the converted polygon-mesh version of the Chinese reference adult male whole-body surface model. After the incorporation, dose conversion coefficients for the eye lens were calculated for neutron exposure at AP, PA and LAT geometries with Geant4, the neutron energies were from 0.001 eV to 10 MeV. The calculated lens dose coefficients were compared with those of ICRP-116 publication. Significant differences up to 97.47% were found at PA geometry. This could mainly be attributed to the different geometry characteristic of eye model and parameters of head in different phantom between the present work and ICRP-116 publication. (authors)

  5. ESTABLISHMENT OF DETAILED EYE MODEL OF ADULT CHINESE MALE AND DOSE CONVERSION COEFFICIENTS CALCULATION UNDER NEUTRON EXPOSURE.

    Science.gov (United States)

    Zhu, Hongyu; Qiu, Rui; Wu, Zhen; Ren, Li; Li, Chunyan; Zhang, Hui; Li, Junli

    2017-12-01

    The human eye lens is sensitive to radiation. ICRP-118 publication recommended a reduction of the occupational annual equivalent dose limit from 150 to 20 mSv, averaged over defined periods of 5 y. Therefore, it is very important to build a detailed eye model for the accurate dose assessment and radiation risk evaluation of eye lens. In this work, a detailed eye model was build based on the characteristic anatomic parameters of the Chinese adult male. This eye model includes seven main structures, which are scleral, choroid, lens, iris, cornea, vitreous body and aqueous humor. The lens was divided into sensitive volume and insensitive volume based on different cell populations. The detailed eye model was incorporated into the converted polygon-mesh version of the Chinese reference adult male whole-body surface model. After the incorporation, dose conversion coefficients for the eye lens were calculated for neutron exposure at AP, PA and LAT geometries with Geant4, the neutron energies were from 0.001 eV to 10 MeV. The calculated lens dose coefficients were compared with those of ICRP-116 publication. Significant differences up to 97.47% were found at PA geometry. This could mainly be attributed to the different geometry characteristic of eye model and parameters of head in different phantom between the present work and ICRP-116 publication. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Protective effect of lycopene for oxidative damage in human lens epithelial cells induced by UV

    Directory of Open Access Journals (Sweden)

    Jing-Wen Sun

    2016-05-01

    Full Text Available AIM:To investigate the protective effect and possible mechanisms of lycopene for oxidative damage induced by ultraviolet in cultured human lens epithelial cells(HLEC. METHODS:HLEC was subcultured and divided into negative control group, oxidative injury group, lycopene low dose group and lycopene high dose group. Cell viability was assayed by MTT colorimetric. Cell morphological changes were detected by electron microscope. Reactive oxygen species(ROSlevels were detected with DCFH-DA fluorescent probe. Content of superoxide dismutase(SOD, glutathione peroxidase(GSHand malondialdehyde(MDAin supernatants were detected by spectrophotometer. RESULTS:Lycopene could obviously inhibited UV-induced decline in cell activity, reduce UV-induced ROS generation within HLEC, cause SOD, GSH-Px levels increased and MDA levels decreased.CONCLUSION:Lycopene plays its strong antioxidant role in increasing the intracellular SOD and GSH-Px content levels and decreasing MDA levels, which provide reliable experimental basis for prevent and treatment of cataracts.

  7. KCC2a expression in a human fetal lens epithelial cell line.

    Science.gov (United States)

    Lauf, Peter K; Di Fulvio, Mauricio; Srivastava, Vinita; Sharma, Neelima; Adragna, Norma C

    2012-01-01

    The fetal human lens epithelial cell (LEC) line (FHL124) possesses all four K(+)Cl(-) (KCC) cotransporter isoforms, KCC1-4, despite KCC2 being typically considered a neuronal isoform. Since at least two spliced variants, KCC2a and KCC2b, are co-expressed in cells of the central nervous system, this study sought to define the KCC2 expression profile in FHL124 cells. KCC2a, but not KCC2b transcripts were detected by reverse transcriptase polymerase chain reaction (RT-PCR). Proteins of molecular weights ranging from 95 to 135 kDa were found by Western blotting using non-variant specific anti-KCC2 antibodies directed against two different regions of the KCC2 proteins, and by biotinylation suggesting membrane expression. Immunofluorescence revealed membrane and punctate cytoplasmic staining for KCC2. Low levels of cytosolic αA and αB crystallines, and neuron-specific enolase were also detected contrasting with the strong membrane immunofluorescence staining for the Na/K ATPase α1 subunit. Since the lack of neuron-specific expression of the KCC2b variant in non-neuronal tissues has been proposed under control of a neuron-restrictive silencing element in the KCC2 gene, we hypothesize that this control may be lifted for the KCC2a variant in the FHL124 epithelial cell culture, a non-neuronal tissue of ectodermal origin. Copyright © 2012 S. Karger AG, Basel.

  8. The Human Eye Position Control System in a Rehabilitation Setting

    Directory of Open Access Journals (Sweden)

    Yvonne Nolan

    2005-01-01

    Full Text Available Our work at Ireland’s National Rehabilitation Hospital involves designing communication systems for people suffering from profound physical disabilities. One such system uses the electro-oculogram, which is an (x,y system of voltages picked up by pairs of electrodes placed, respectively, above and below and on either side of the eyes. The eyeball has a dc polarisation between cornea and back, arising from the photoreceptor rods and cones in the retina. As the eye rotates, the varying voltages projected onto the electrodes drive a cursor over a mimic keyboard on a computer screen. Symbols are selected with a switching action derived, for example, from a blink. Experience in using this mode of communication has given us limited facilities to study the eye position control system. We present here a resulting new feedback model for rotation in either the vertical or the horizontal plane, which involves the eyeball controlled by an agonist-antagonist muscle pair, modelled by a single equivalent bidirectional muscle with torque falling off linearly with angular velocity. We have incorporated muscle spindles and have tuned them by pole assignment associated with an optimum stability criterion.

  9. 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...

  10. A generalised porous medium approach to study thermo-fluid dynamics in human eyes.

    Science.gov (United States)

    Mauro, Alessandro; Massarotti, Nicola; Salahudeen, Mohamed; Romano, Mario R; Romano, Vito; Nithiarasu, Perumal

    2018-03-22

    The present work describes the application of the generalised porous medium model to study heat and fluid flow in healthy and glaucomatous eyes of different subject specimens, considering the presence of ocular cavities and porous tissues. The 2D computational model, implemented into the open-source software OpenFOAM, has been verified against benchmark data for mixed convection in domains partially filled with a porous medium. The verified model has been employed to simulate the thermo-fluid dynamic phenomena occurring in the anterior section of four patient-specific human eyes, considering the presence of anterior chamber (AC), trabecular meshwork (TM), Schlemm's canal (SC), and collector channels (CC). The computational domains of the eye are extracted from tomographic images. The dependence of TM porosity and permeability on intraocular pressure (IOP) has been analysed in detail, and the differences between healthy and glaucomatous eye conditions have been highlighted, proving that the different physiological conditions of patients have a significant influence on the thermo-fluid dynamic phenomena. The influence of different eye positions (supine and standing) on thermo-fluid dynamic variables has been also investigated: results are presented in terms of velocity, pressure, temperature, friction coefficient and local Nusselt number. The results clearly indicate that porosity and permeability of TM are two important parameters that affect eye pressure distribution. Graphical abstract Velocity contours and vectors for healthy eyes (top) and glaucomatous eyes (bottom) for standing position.

  11. Early visual evoked potentials are modulated by eye position in humans induced by whole body rotations

    Directory of Open Access Journals (Sweden)

    Petit Laurent

    2004-09-01

    Full Text Available Abstract Background To reach and grasp an object in space on the basis of its image cast on the retina requires different coordinate transformations that take into account gaze and limb positioning. Eye position in the orbit influences the image's conversion from retinotopic (eye-centered coordinates to an egocentric frame necessary for guiding action. Neuroimaging studies have revealed eye position-dependent activity in extrastriate visual, parietal and frontal areas that is along the visuo-motor pathway. At the earliest vision stage, the role of the primary visual area (V1 in this process remains unclear. We used an experimental design based on pattern-onset visual evoked potentials (VEP recordings to study the effect of eye position on V1 activity in humans. Results We showed that the amplitude of the initial C1 component of VEP, acknowledged to originate in V1, was modulated by the eye position. We also established that putative spontaneous small saccades related to eccentric fixation, as well as retinal disparity cannot explain the effects of changing C1 amplitude of VEP in the present study. Conclusions The present modulation of the early component of VEP suggests an eye position-dependent activity of the human primary visual area. Our findings also evidence that cortical processes combine information about the position of the stimulus on the retinae with information about the location of the eyes in their orbit as early as the stage of primary visual area.

  12. 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 ...

  13. Anterior segment and retinal OCT imaging with simplified sample arm using focus tunable lens technology (Conference Presentation)

    Science.gov (United States)

    Grulkowski, Ireneusz; Karnowski, Karol; Ruminski, Daniel; Wojtkowski, Maciej

    2016-03-01

    Availability of the long-depth-range OCT systems enables comprehensive structural imaging of the eye and extraction of biometric parameters characterizing the entire eye. Several approaches have been developed to perform OCT imaging with extended depth ranges. In particular, current SS-OCT technology seems to be suited to visualize both anterior and posterior eye in a single measurement. The aim of this study is to demonstrate integrated anterior segment and retinal SS-OCT imaging using a single instrument, in which the sample arm is equipped with the electrically tunable lens (ETL). ETL is composed of the optical liquid confined in the space by an elastic polymer membrane. The shape of the membrane, electrically controlled by a specific ring, defines the radius of curvature of the lens surface, thus it regulates the power of the lens. ETL can be also equipped with additional offset lens to adjust the tuning range of the optical power. We characterize the operation of the tunable lens using wavefront sensing. We develop the optimized optical set-up with two adaptive operational states of the ETL in order to focus the light either on the retina or on the anterior segment of the eye. We test the performance of the set-up by utilizing whole eye phantom as the object. Finally, we perform human eye in vivo imaging using the SS-OCT instrument with versatile imaging functionality that accounts for the optics of the eye and enables dynamic control of the optical beam focus.

  14. The effects of two different types of bandage contact lenses on the healthy canine eye.

    Science.gov (United States)

    Braus, Barbara Katharina; Riedler, Daniela; Tichy, Alexander; Spergser, Joachim; Schwendenwein, Ilse

    2018-02-06

    To compare two types of bandage contact lenses on the healthy canine eye. Six healthy Beagles. Two different types of bandage contact lenses (single sized human silicone contact lens 'PureVision 2' (Bausch & Lomb Incorporated, Rochester, NY, USA) and specially designed veterinary hydrogel contact lens 'AcriVet Pat D' (Bausch & Lomb Incorporated) were placed in 12 eyes of healthy Beagle dogs. Retention times and the effects of the lenses regarding irritation of the eye, changes in tear production, impact of contact lenses on tonometric readings, and cytologic and microbiological alterations of the canine eye were investigated. Mean retention times for veterinary hydrogel lenses with special dimensions were significantly shorter (2 days) than for one size human silicon lenses (8.8 days). Irritation scores were overall low for both types of lenses apart from one human lens causing severe irritation and keratoconjunctivitis as a sequel to folding and displacement. Tear production remained stable in human contact lenses. Intraocular pressure readings with a contact lens in place were only slightly altered; the most accurate readings were obtained through a human lens with an applanation tonometer. Cytology revealed a slight, nonsignificant increase in neutrophilic granulocytes with both types of lenses; the microflora did not change significantly. Human silicone lenses have significantly longer retention times and are less expensive than veterinary hydrogel lenses. In regard to irritation, bacterial growth and inflammation, both types of lenses can be recommended for use in canine eyes. © 2018 American College of Veterinary Ophthalmologists.

  15. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models

    OpenAIRE

    Song, Hui; Yuan, Xiaoyong; Tang, Xin

    2016-01-01

    Background In this study, the effects of intraocular lenses (IOLs) with different diopters (D) on chromatic aberration were investigated in human eye models, and the influences of the central thickness of IOLs on chromatic aberration were compared. Methods A Liou-Brennan-based IOL eye model was constructed using ZEMAX optical design software. Spherical IOLs with different diopters (AR40e, AMO Company, USA) were implanted; modulation transfer function (MTF) values at 3?mm of pupil diameter and...

  16. 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

  17. 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.

  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. 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

  20. Electrophoretic study on intraspecific variations and interspecific relationships of marine catfishes (Siluriformes, Ariidae of Cananéia (São Paulo, Brazil: 1. General proteins of eye-lens and skeletic muscle

    Directory of Open Access Journals (Sweden)

    Hana Suzuki

    1990-06-01

    Full Text Available Cellulose acetate electrophoresis of eye-lens proteins and Polyacrylamide flat gel electrophoresis of skeletic muscle proteins of six species of marine catfishes were carried out. Genetic polymorphism only occured at one locus of the electropherograms of eye-lens of Cathorops spixii. Ontogenetic variations in the relative concentration of bands were found in the electropherograms of eye-lens and skeletic muscle proteins. The six species of catfishes can be identified by means of quantitative and qualitative differences in the electropherograms. Coefficients of similarity were determined by the band-counting method and UPGMA dendrograms were constructed to illustrate the interspecific relationships among the species.Eletroforeses de proteínas gerais de cristalinos e de músculo esquelético de seis espécies de bagres marinhos foram realizadas, respectivamente, em membranas de acetato de celulose e em géis de poliacrilamida. Polimorfismo genético ocorreu apenas em um locus de eletroferogramas do cristalino de Cathorops spixii. Variações ontogenéticas nas concentrações relativas das bandas foram observadas nos eletroferogramas do cristalino e do músculo esquelético. As seis espécies de bagres marinhos podem ser identificadas através das diferenças quantitativas e qualitativas nos eletroferogramas. Coeficientes de similaridade foram determinadas pelo método de contagem de bandas e dendrogramas UPGMA foram construídos para ilustrar as relações interespecíficas entre as espécies.

  1. See You See Me: the Role of Eye Contact in Multimodal Human-Robot Interaction.

    Science.gov (United States)

    Xu, Tian Linger; Zhang, Hui; Yu, Chen

    2016-05-01

    We focus on a fundamental looking behavior in human-robot interactions - gazing at each other's face. Eye contact and mutual gaze between two social partners are critical in smooth human-human interactions. Therefore, investigating at what moments and in what ways a robot should look at a human user's face as a response to the human's gaze behavior is an important topic. Toward this goal, we developed a gaze-contingent human-robot interaction system, which relied on momentary gaze behaviors from a human user to control an interacting robot in real time. Using this system, we conducted an experiment in which human participants interacted with the robot in a joint attention task. In the experiment, we systematically manipulated the robot's gaze toward the human partner's face in real time and then analyzed the human's gaze behavior as a response to the robot's gaze behavior. We found that more face looks from the robot led to more look-backs (to the robot's face) from human participants and consequently created more mutual gaze and eye contact between the two. Moreover, participants demonstrated more coordinated and synchronized multimodal behaviors between speech and gaze when more eye contact was successfully established and maintained.

  2. A Proactive Approach of Robotic Framework for Making Eye Contact with Humans

    Directory of Open Access Journals (Sweden)

    Mohammed Moshiul Hoque

    2014-01-01

    Full Text Available Making eye contact is a most important prerequisite function of humans to initiate a conversation with others. However, it is not an easy task for a robot to make eye contact with a human if they are not facing each other initially or the human is intensely engaged his/her task. If the robot would like to start communication with a particular person, it should turn its gaze to that person and make eye contact with him/her. However, such a turning action alone is not enough to set up an eye contact phenomenon in all cases. Therefore, the robot should perform some stronger actions in some situations so that it can attract the target person before meeting his/her gaze. In this paper, we proposed a conceptual model of eye contact for social robots consisting of two phases: capturing attention and ensuring the attention capture. Evaluation experiments with human participants reveal the effectiveness of the proposed model in four viewing situations, namely, central field of view, near peripheral field of view, far peripheral field of view, and out of field of view.

  3. Ion transport in a human lens epithelial cell line exposed to hyposmotic and apoptotic stress.

    Science.gov (United States)

    Chimote, Ameet A; Adragna, Norma C; Lauf, Peter K

    2010-04-01

    Membrane transport changes in human lens epithelial (HLE-B3) cells under hyposmotic and apoptotic stress were compared. Cell potassium content, K(i), uptake of the K congener rubidium, Rb(i), and water content were measured after hyposmotic stress induced by hypotonicity, and apoptotic stress by the protein-kinase inhibitor staurosporine (STP). Cell water increased in hyposmotic (150 mOsm) as compared to isosmotic (300 mOsm) balanced salt solution (BSS) by >2-fold at 5 min and decreased within 15 min to baseline values accompanied by a 40% K(i) loss commensurate with cell swelling and subsequent cell shrinkage likely due to regulatory volume decrease (RVD). Loss of K(i), and accompanying water, and Rb(i) uptake in hyposmotic BSS were prevented by clotrimazole (CTZ) suggesting water shifts associated with K and Rb flux via intermediate conductance K (IK) channels, also detected at the mRNA and protein level. In contrast, 2 h after 2 microM STP exposure, the cells lost approximately 40% water and approximately 60% K(i), respectively, consistent with apoptotic volume decrease (AVD). Indeed, water and K(i) loss was at least fivefold greater after hyposmotic than after apoptotic stress. High extracellular K and 2 mM 4-aminopyridine (4-AP) but not CTZ significantly reduced apoptosis. Annexin labeling phosphatidylserine (PS) at 15 min suggested loss of lipid asymmetry. Quantitative PCR revealed significant IK channel expression during prolonged hyposmotic stress. Results suggest in HLE-B3 cells, IK channels likely partook in and were down regulated after RVD, whereas pro-apoptotic STP-activation of 4-AP-sensitive voltage-gated K channels preceded or accompanied PS externalization before subsequent apoptosis. J. Cell. Physiol. 223: 110-122, 2010. (c) 2009 Wiley-Liss, Inc.

  4. Apparent intermediate K conductance channel hyposmotic activation in human lens epithelial cells.

    Science.gov (United States)

    Lauf, Peter K; Misri, Sandeep; Chimote, Ameet A; Adragna, Norma C

    2008-03-01

    This study explores the nature of K fluxes in human lens epithelial cells (LECs) in hyposmotic solutions. Total ion fluxes, Na-K pump, Cl-dependent Na-K-2Cl (NKCC), K-Cl (KCC) cotransport, and K channels were determined by 85Rb uptake and cell K (Kc) by atomic absorption spectrophotometry, and cell water gravimetrically after exposure to ouabain +/- bumetanide (Na-K pump and NKCC inhibitors), and ion channel inhibitors in varying osmolalities with Na, K, or methyl-d-glucamine and Cl, sulfamate, or nitrate. Reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analyses, and immunochemistry were also performed. In isosmotic (300 mosM) media approximately 90% of the total Rb influx occurred through the Na-K pump and NKCC and approximately 10% through KCC and a residual leak. Hyposmotic media (150 mosM) decreased K(c) by a 16-fold higher K permeability and cell water, but failed to inactivate NKCC and activate KCC. Sucrose replacement or extracellular K to >57 mM, but not Rb or Cs, in hyposmotic media prevented Kc and water loss. Rb influx equaled Kc loss, both blocked by clotrimazole (IC50 approximately 25 microM) and partially by 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34) inhibitors of the IK channel KCa3.1 but not by other K channel or connexin hemichannel blockers. Of several anion channel blockers (dihydro-indenyl)oxy]alkanoic acid (DIOA), 4-2(butyl-6,7-dichloro-2-cyclopentylindan-1-on-5-yl)oxybutyric acid (DCPIB), and phloretin totally or partially inhibited Kc loss and Rb influx, respectively. RT-PCR and immunochemistry confirmed the presence of KCa3.1 channels, aside of the KCC1, KCC2, KCC3 and KCC4 isoforms. Apparently, IK channels, possibly in parallel with volume-sensitive outwardly rectifying Cl channels, effect regulatory volume decrease in LECs.

  5. Geometrical theory to predict eccentric photorefraction intensity profiles in the human eye

    Science.gov (United States)

    Roorda, Austin; Campbell, Melanie C. W.; Bobier, W. R.

    1995-08-01

    In eccentric photorefraction, light returning from the retina of the eye is photographed by a camera focused on the eye's pupil. We use a geometrical model of eccentric photorefraction to generate intensity profiles across the pupil image. The intensity profiles for three different monochromatic aberration functions induced in a single eye are predicted and show good agreement with the measured eccentric photorefraction intensity profiles. A directional reflection from the retina is incorporated into the calculation. Intensity profiles for symmetric and asymmetric aberrations are generated and measured. The latter profile shows a dependency on the source position and the meridian. The magnitude of the effect of thresholding on measured pattern extents is predicted. Monochromatic aberrations in human eyes will cause deviations in the eccentric photorefraction measurements from traditional crescents caused by defocus and may cause misdiagnoses of ametropia or anisometropia. Our results suggest that measuring refraction along the vertical meridian is preferred for screening studies with the eccentric photorefractor.

  6. Importance of non-synonymous OCA2 variants in human eye colour prediction

    DEFF Research Database (Denmark)

    Andersen, Jeppe Dyrberg; Pietroni, Carlotta; Johansen, Peter

    2016-01-01

    in the promotor region of OCA2 (OMIM #611409). Nevertheless, many eye colors cannot be explained by only considering rs12913832:A>G. Methods: In this study, we searched for additional variants in OCA2 to explain human eye color by sequencing a 500 kbp region, encompassing OCA2 and its promotor region. Results: We...... identified three nonsynonymous OCA2 variants as important for eye color, including rs1800407:G>A (p.Arg419Gln) and two variants, rs74653330:A>T (p.Ala481Thr) and rs121918166:G>A (p.Val443Ile), not previously described as important for eye color variation. It was shown that estimated haplotypes consisting...

  7. 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.

  8. Towards Quantum Experiments with Human Eye Detectors Based on Cloning via Stimulated Emission ?

    Science.gov (United States)

    De Martini, Francesco

    2010-05-01

    In a recent theoretical paper published in Physical Review Letters, Sekatsky, Brunner, Branciard, Gisin, Simon report an extended investigation on some properties of the human eye that affect its behavior as a quantum detector. We believe that the content of this work, albeit appealing at fist sight, is highly questionable simply because the human eye cannot be adopted as a sensing device within any quantum measurement apparatus. Furthermore, the criticism raised by these Authors against a real experiment on Micro—Macro entanglement recently published in Physical Review Letters (100, 253601, 2008) is found misleading and misses its target.

  9. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... edging closer, thanks to a wave of new technologies aiming to fix failing eye parts with human-made versions. ... tips and information about eye health and preserving your vision. Privacy ...

  10. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... edging closer, thanks to a wave of new technologies aiming to fix failing eye parts with human- ... Answers Free Newsletter Get ophthalmologist-reviewed tips and information about eye health and preserving your vision. Privacy ...

  11. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... edging closer, thanks to a wave of new technologies aiming to fix failing eye parts with human-made versions. ... ophthalmologist-reviewed tips and information about eye health and preserving your vision. Privacy ...

  12. Non-invasive bleaching of the human lens by femtosecond laser photolysis

    DEFF Research Database (Denmark)

    Kessel, L.; Eskildsen, Lars; Poel, Mike van der

    2010-01-01

    . Reducing blindness from cataract requires solutions that can be applied outside operating theatres. Cataract is a protein conformational disease characterized by accumulation of light absorbing, fluorescent and scattering protein aggregates. The aim of the study was to investigate whether these compounds...... by a non-invasive procedure based on femtosecond laser photolysis. Cataract is a disease associated with old age. At the current technological stage, lens aging is delayed but with a treatment covering the entire lens volume complete optical rejuvenation is expected. Thus, femtosecond photolysis has...

  13. Pentacam Scheimpflug quantitative imaging of the crystalline lens and intraocular lens.

    Science.gov (United States)

    Rosales, Patricia; Marcos, Susana

    2009-05-01

    To implement geometrical and optical distortion correction methods for anterior segment Scheimpflug images obtained with a commercially available system (Pentacam, Oculus Optikgeräte GmbH). Ray tracing algorithms were implemented to obtain corrected ocular surface geometry from the original images captured by the Pentacam's CCD camera. As details of the optical layout were not fully provided by the manufacturer, an iterative procedure (based on imaging of calibrated spheres) was developed to estimate the camera lens specifications. The correction procedure was tested on Scheimpflug images of a physical water cell model eye (with polymethylmethacrylate cornea and a commercial IOL of known dimensions) and of a normal human eye previously measured with a corrected optical and geometrical distortion Scheimpflug camera (Topcon SL-45 [Topcon Medical Systems Inc] from the Vrije University, Amsterdam, Holland). Uncorrected Scheimpflug images show flatter surfaces and thinner lenses than in reality. The application of geometrical and optical distortion correction algorithms improves the accuracy of the estimated anterior lens radii of curvature by 30% to 40% and of the estimated posterior lens by 50% to 100%. The average error in the retrieved radii was 0.37 and 0.46 mm for the anterior and posterior lens radii of curvature, respectively, and 0.048 mm for lens thickness. The Pentacam Scheimpflug system can be used to obtain quantitative information on the geometry of the crystalline lens, provided that geometrical and optical distortion correction algorithms are applied, within the accuracy of state-of-the art phakometry and biometry. The techniques could improve with exact knowledge of the technical specifications of the instrument, improved edge detection algorithms, consideration of aspheric and non-rotationally symmetrical surfaces, and introduction of a crystalline gradient index.

  14. Statistical characteristics of aberrations of human eyes after small incision lenticule extraction surgery and analysis of visual performance with individual eye model.

    Science.gov (United States)

    Lou, Qiqi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; Fang, Hui

    2015-09-01

    Preoperative and postoperative wavefront aberrations of 73 myopic eyes with small incision lenticule extraction surgery are analyzed in this paper. Twenty-eight postoperative individual eye models are constructed to investigate the visual acuity (VA) of human eyes. Results show that in photopic condition, residual defocus, residual astigmatism, and higher-order aberrations are relatively small. 100% of eyes reach a VA of 0.8 or better, and 89.3% of eyes reach a VA of 1.0 or better. In scotopic condition, the residual defocus and the higher-order aberrations are, respectively, 1.9 and 8.5 times the amount of that in photopic condition, and the defocus becomes the main factor attenuating visual performance.

  15. APPLICATION OF EYE TRACKING FOR MEASUREMENT AND EVALUATION IN HUMAN FACTORS STUDIES IN CONTROL ROOM MODERNIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Kovesdi, C.; Spielman, Z.; LeBlanc, K.; Rice, B.

    2017-05-01

    An important element of human factors engineering (HFE) pertains to measurement and evaluation (M&E). The role of HFE-M&E should be integrated throughout the entire control room modernization (CRM) process and be used for human-system performance evaluation and diagnostic purposes with resolving potential human engineering deficiencies (HEDs) and other human machine interface (HMI) design issues. NUREG-0711 describes how HFE in CRM should employ a hierarchical set of measures, particularly during integrated system validation (ISV), including plant performance, personnel task performance, situation awareness, cognitive workload, and anthropometric/ physiological factors. Historically, subjective measures have been primarily used since they are easier to collect and do not require specialized equipment. However, there are pitfalls with relying solely on subjective measures in M&E such that negatively impact reliability, sensitivity, and objectivity. As part of comprehensively capturing a diverse set of measures that strengthen findings and inferences made of the benefits from emerging technologies like advanced displays, this paper discusses the value of using eye tracking as an objective method that can be used in M&E. A brief description of eye tracking technology and relevant eye tracking measures is provided. Additionally, technical considerations and the unique challenges with using eye tracking in full-scaled simulations are addressed. Finally, this paper shares preliminary findings regarding the use of a wearable eye tracking system in a full-scale simulator study. These findings should help guide future full-scale simulator studies using eye tracking as a methodology to evaluate human-system performance.

  16. See You See Me: the Role of Eye Contact in Multimodal Human-Robot Interaction

    Science.gov (United States)

    XU, TIAN (LINGER); ZHANG, HUI; YU, CHEN

    2016-01-01

    We focus on a fundamental looking behavior in human-robot interactions – gazing at each other’s face. Eye contact and mutual gaze between two social partners are critical in smooth human-human interactions. Therefore, investigating at what moments and in what ways a robot should look at a human user’s face as a response to the human’s gaze behavior is an important topic. Toward this goal, we developed a gaze-contingent human-robot interaction system, which relied on momentary gaze behaviors from a human user to control an interacting robot in real time. Using this system, we conducted an experiment in which human participants interacted with the robot in a joint attention task. In the experiment, we systematically manipulated the robot’s gaze toward the human partner’s face in real time and then analyzed the human’s gaze behavior as a response to the robot’s gaze behavior. We found that more face looks from the robot led to more look-backs (to the robot’s face) from human participants and consequently created more mutual gaze and eye contact between the two. Moreover, participants demonstrated more coordinated and synchronized multimodal behaviors between speech and gaze when more eye contact was successfully established and maintained. PMID:28966875

  17. About the Eye

    Medline Plus

    Full Text Available ... about each part of your eye and what it does. Macula (MACK-yoo-luh) is the small, ... area of the retina needed for central vision. It contains the fovea. Lens is the clear part ...

  18. Original Article Effect of Soft Contact Lens Materials on Tear Film ...

    African Journals Online (AJOL)

    problems, results in intolerance of contact lens wear and damage (Foulks, ... reported that contact lens-related dry eye may be ... eliminating or modifying the refractive error ..... risk of eye infection, easier handling due to ... Adv Exp Med Biol.

  19. Thioredoxin Reductase Activity may be More Important than GSH Level in Protecting Human Lens Epithelial Cells Against UVA Light

    Science.gov (United States)

    Padgaonkar, Vanita A.; Leverenz, Victor R.; Bhat, Aparna V.; Pelliccia, Sara E.; Giblin, Frank J.

    2014-01-01

    This study compares the abilities of the glutathione (GSH) and thioredoxin (Trx) antioxidant systems in defending cultured human lens epithelial cells (LECs) against UVA light. Levels of GSH were depleted with either L-buthionine-(S,R)-sulfoximine (BSO) or 1-chloro-2,4-dinitrobenzene (CDNB). CDNB treatment also inhibited the activity of thioredoxin reductase (TrxR). Two levels of O2, 3% and 20%, were employed during a 1 hr exposure of the cells to 25 J/cm2 of UVA radiation (338-400nm wavelength, peak at 365nm). Inhibition of TrxR activity by CDNB, combined with exposure to UVA light, produced a substantial loss of LECs and cell damage, with the effects being considerably more severe at 20% O2 compared to 3%. In contrast, depletion of GSH by BSO, combined with exposure to UVA light, produced only a slight cell loss, with no apparent morphological effects. Catalase was highly sensitive to UVA-induced inactivation, but was not essential for protection. Although UVA light presented a challenge for the lens epithelium, it was well-tolerated under normal conditions. The results demonstrate an important role for TrxR activity in defending the lens epithelium against UVA light, possibly related to the ability of the Trx system to assist DNA synthesis following UVA-induced cell damage. PMID:25495870

  20. A model of the human retina

    DEFF Research Database (Denmark)

    Jørgensen, John Leif

    1998-01-01

    Traditionally, the human eye is perceived as being "just" a camera, that renders an accurate, although limited, image for processing in the brain. This interpretation probably stems from the apparent similarity between a video- or photo-camera and a human eye with respect to the lens, the iris...

  1. Mathematical models of the dynamics of the human eye

    CERN Document Server

    Collins, Richard

    1980-01-01

    A rich and abundant literature has developed during the last half century dealing with mechanical aspects of the eye, mainly from clinical and, experimental points of view. For the most part, workers have attempted to shed light on the complex set of conditions known by the general term glaucoma. These conditions are characterised by an increase in intraocular pressure sufficient to cause de­ generation of the optic disc and concomitant defects in the visual field, which, if not controlled, lead to inevitable permanent blindness. In the United States alone, an estimated 50,000 persons are blind as a result of glaucoma, which strikes about 2% of the population over 40 years of age (Vaughan and Asbury, 1974). An understanding of the underlying mechanisms of glaucoma is hindered by the fact that elevated intraocular pressure, like a runny nose, is but a symptom which may have a variety of causes. Only by turning to the initial pathology can one hope to understand this important class of medical problems.

  2. 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. ...

  3. MORPHOLOGICAL ASPECTS OF HUMAN LENS CAPSULES - A COMPARATIVE LM, SEM AND TEM EXAMINATION

    NARCIS (Netherlands)

    JONGEBLOED, WL; KALICHARAN, D; LOS, LI; VANDERVEEN, G; WORST, JGF

    1991-01-01

    Lens capsules of patients of advanced age, obtained after extracapsular cataract surgery, were carefully prepared for a combined LM, TEM and SEM investigation, after preliminary washing and mounting onto a holder in a buffer solution. After pre-fixation with GA, samples were postfixed for LM/TEM and

  4. The effect of human image in B2C website design: an eye-tracking study

    Science.gov (United States)

    Wang, Qiuzhen; Yang, Yi; Wang, Qi; Ma, Qingguo

    2014-09-01

    On B2C shopping websites, effective visual designs can bring about consumers' positive emotional experience. From this perspective, this article developed a research model to explore the impact of human image as a visual element on consumers' online shopping emotions and subsequent attitudes towards websites. This study conducted an eye-tracking experiment to collect both eye movement data and questionnaire data to test the research model. Questionnaire data analysis showed that product pictures combined with human image induced positive emotions among participants, thus promoting their attitudes towards online shopping websites. Specifically, product pictures with human image first produced higher levels of image appeal and perceived social presence, thus stimulating higher levels of enjoyment and subsequent positive attitudes towards the websites. Moreover, a moderating effect of product type was demonstrated on the relationship between the presence of human image and the level of image appeal. Specifically, human image significantly increased the level of image appeal when integrated in entertainment product pictures while this relationship was not significant in terms of utilitarian products. Eye-tracking data analysis further supported these results and provided plausible explanations. The presence of human image significantly increased the pupil size of participants regardless of product types. For entertainment products, participants paid more attention to product pictures integrated with human image whereas for utilitarian products more attention was paid to functional information of products than to product pictures no matter whether or not integrated with human image.

  5. 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...

  6. Mechanical model of human eye compliance for volumetric occlusion break surge measurements.

    Science.gov (United States)

    Dyk, David W; Miller, Kevin M

    2018-02-01

    To develop a mechanical model of human eye compliance for volumetric studies. Alcon Research, Ltd., Lake Forest, California, USA. Experimental study. Enucleated human eyes underwent pressurization and depressurization cycles with peak intraocular pressures (IOPs) of 60 to 100 mm Hg; anterior chamber pressure and volume changes were measured. Average net volume change curves were calculated as a function of IOP for each eye. Overall mean volumes were computed from each eye's average results at pressure points extrapolated over the range of 5 to 90 mm Hg. A 2-term exponential function was fit to these results. A fluid chamber with a displaceable piston was created as a mechanical model of this equation. A laser confocal displacement meter was used to measure piston displacement. A test bed incorporated the mechanical model with a mounted phacoemulsification probe and allowed for simulated occlusion breaks. Surge volume was calculated from piston displacement. An exponential function, V = C 1 × exp(C 2 × IOP) + C 3  × exp(C 4  × IOP) - V 0 , where V, the volume, was fit to the final depressurization curve obtained from 15 enucleated human eyes. The C 1 through C 4 values were -0.07141, -0.23055, -0.14972, and -0.02006, respectively. The equation was modeled using a piston system with 3 parallel springs that engaged serially. The mechanical model mimicked depressurization curves observed in human cadaver eyes. The resulting mechanical compliance model measured ocular volumetric changes and thus would be helpful in characterizing the postocclusion break surge response. Copyright © 2018 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  7. Social interactions through the eyes of macaques and humans.

    Directory of Open Access Journals (Sweden)

    Richard McFarland

    Full Text Available Group-living primates frequently interact with each other to maintain social bonds as well as to compete for valuable resources. Observing such social interactions between group members provides individuals with essential information (e.g. on the fighting ability or altruistic attitude of group companions to guide their social tactics and choice of social partners. This process requires individuals to selectively attend to the most informative content within a social scene. It is unclear how non-human primates allocate attention to social interactions in different contexts, and whether they share similar patterns of social attention to humans. Here we compared the gaze behaviour of rhesus macaques and humans when free-viewing the same set of naturalistic images. The images contained positive or negative social interactions between two conspecifics of different phylogenetic distance from the observer; i.e. affiliation or aggression exchanged by two humans, rhesus macaques, Barbary macaques, baboons or lions. Monkeys directed a variable amount of gaze at the two conspecific individuals in the images according to their roles in the interaction (i.e. giver or receiver of affiliation/aggression. Their gaze distribution to non-conspecific individuals was systematically varied according to the viewed species and the nature of interactions, suggesting a contribution of both prior experience and innate bias in guiding social attention. Furthermore, the monkeys' gaze behavior was qualitatively similar to that of humans, especially when viewing negative interactions. Detailed analysis revealed that both species directed more gaze at the face than the body region when inspecting individuals, and attended more to the body region in negative than in positive social interactions. Our study suggests that monkeys and humans share a similar pattern of role-sensitive, species- and context-dependent social attention, implying a homologous cognitive mechanism of

  8. 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.

  9. Lithium fluxes indicate presence of Na-Cl cotransport (NCC) in human lens epithelial cells.

    Science.gov (United States)

    Lauf, Peter K; Chimote, Ameet A; Adragna, Norma C

    2008-01-01

    During regulatory volume decrease (RVD) of human lens epithelial cells (hLECs) by clotrimazole (CTZ)-sensitive K fluxes, Na-K-2Cl cotransport (NKCC) remains active and K-Cl cotransport (KCC) inactive. To determine whether such an abnormal behavior was caused by RVD-induced cell shrinkage, NKCC was measured in the presence of either CTZ or in high K media to prevent RVD. NKCC transports RbCl + NaCl, and LiCl + KCl; thus ouabain-insensitive, bumetanide-sensitive (BS) or Cl-dependent (ClD) Rb and Li fluxes were determined in hyposmotic high NaCl media with CTZ, or in high KCl media alone, or with sulfamate (Sf) or nitrate as Cl replacement at varying Rb, Li or Cl mol fractions (MF). Unexpectedly, NKCC was inhibited by 80% with CTZ (IC(50) = 31 microM). In isosmotic (300 mOsM) K, Li influx was approximately 1/3 of Rb influx in Na, 50% lower in Sf, and bumetanide-insensitive (BI). In hypotonic (200 mOsM) K, only the ClD but not BS Li fluxes were detected. At Li MFs from 0.1-1, Li fluxes fitted a bell-shaped curve maxing at approximately 0.6 Li MF, with the BS fluxes equaling approximately 1/4 of the ClD-Li influx. The difference, i.e. the BI/ClD Li influx, saturated with increasing Li and Cl MFs, with K(ms) for Li of 11 with, and 7 mM without K, and of approximately 46 mM for Cl. Inhibition of this K-independent Li influx by thiazides was weak whilst furosemide (<100 microM) was ineffective. Reverse transcription polymerase chain reaction and Western blots verified presence of both NKCC1 and Na-Cl cotransport (NCC). In conclusion, in hyposmotic high K media, which prevents CTZ-sensitive K flux-mediated RVD in hLECs, NKCC1, though molecularly expressed, was functionally silent. However, a K-independent and moderately thiazide-sensitive ClD-Li flux, i.e. LiCC, likely occurring through NCC was detected operationally and molecularly. (c) 2008 S. Karger AG, Basel.

  10. Eye Tracking Based Control System for Natural Human-Computer Interaction

    Directory of Open Access Journals (Sweden)

    Xuebai Zhang

    2017-01-01

    Full Text Available Eye movement can be regarded as a pivotal real-time input medium for human-computer communication, which is especially important for people with physical disability. In order to improve the reliability, mobility, and usability of eye tracking technique in user-computer dialogue, a novel eye control system with integrating both mouse and keyboard functions is proposed in this paper. The proposed system focuses on providing a simple and convenient interactive mode by only using user’s eye. The usage flow of the proposed system is designed to perfectly follow human natural habits. Additionally, a magnifier module is proposed to allow the accurate operation. In the experiment, two interactive tasks with different difficulty (searching article and browsing multimedia web were done to compare the proposed eye control tool with an existing system. The Technology Acceptance Model (TAM measures are used to evaluate the perceived effectiveness of our system. It is demonstrated that the proposed system is very effective with regard to usability and interface design.

  11. Eye Tracking Based Control System for Natural Human-Computer Interaction.

    Science.gov (United States)

    Zhang, Xuebai; Liu, Xiaolong; Yuan, Shyan-Ming; Lin, Shu-Fan

    2017-01-01

    Eye movement can be regarded as a pivotal real-time input medium for human-computer communication, which is especially important for people with physical disability. In order to improve the reliability, mobility, and usability of eye tracking technique in user-computer dialogue, a novel eye control system with integrating both mouse and keyboard functions is proposed in this paper. The proposed system focuses on providing a simple and convenient interactive mode by only using user's eye. The usage flow of the proposed system is designed to perfectly follow human natural habits. Additionally, a magnifier module is proposed to allow the accurate operation. In the experiment, two interactive tasks with different difficulty (searching article and browsing multimedia web) were done to compare the proposed eye control tool with an existing system. The Technology Acceptance Model (TAM) measures are used to evaluate the perceived effectiveness of our system. It is demonstrated that the proposed system is very effective with regard to usability and interface design.

  12. A role of the human thalamus in predicting the perceptual consequences of eye movements.

    Science.gov (United States)

    Ostendorf, Florian; Liebermann, Daniela; Ploner, Christoph J

    2013-01-01

    Internal monitoring of oculomotor commands may help to anticipate and keep track of changes in perceptual input imposed by our eye movements. Neurophysiological studies in non-human primates identified corollary discharge (CD) signals of oculomotor commands that are conveyed via thalamus to frontal cortices. We tested whether disruption of these monitoring pathways on the thalamic level impairs the perceptual matching of visual input before and after an eye movement in human subjects. Fourteen patients with focal thalamic stroke and 20 healthy control subjects performed a task requiring a perceptual judgment across eye movements. Subjects reported the apparent displacement of a target cue that jumped unpredictably in sync with a saccadic eye movement. In a critical condition of this task, six patients exhibited clearly asymmetric perceptual performance for rightward vs. leftward saccade direction. Furthermore, perceptual judgments in seven patients systematically depended on oculomotor targeting errors, with self-generated targeting errors erroneously attributed to external stimulus jumps. Voxel-based lesion-symptom mapping identified an area in right central thalamus as critical for the perceptual matching of visual space across eye movements. Our findings suggest that trans-thalamic CD transmission decisively contributes to a correct prediction of the perceptual consequences of oculomotor actions.

  13. A role of the human thalamus in predicting the perceptual consequences of eye movements

    Directory of Open Access Journals (Sweden)

    Florian eOstendorf

    2013-04-01

    Full Text Available Internal monitoring of oculomotor commands may help to anticipate and keep track of changes in perceptual input imposed by our eye movements. Neurophysiological studies in non-human primates identified corollary discharge signals of oculomotor commands that are conveyed via thalamus to frontal cortices. We tested whether disruption of these monitoring pathways on the thalamic level impairs the perceptual matching of visual input before and after an eye movement in human subjects. Fourteen patients with focal thalamic stroke and twenty healthy control subjects performed a task requiring a perceptual judgment across eye movements. Subjects reported the apparent displacement of a target cue that jumped unpredictably in sync with a saccadic eye movement. In a critical condition of this task, six patients exhibited clearly asymmetric perceptual performance for rightward versus leftward saccade direction. Furthermore, perceptual judgments in seven patients systematically depended on oculomotor targeting errors, with self-generated targeting errors erroneously attributed to external stimulus jumps. Voxel-based lesion-symptom mapping identified an area in right central thalamus as critical for the perceptual matching of visual space across eye movements. Our findings suggest that trans-thalamic corollary discharge transmission decisively contributes to a correct prediction of the perceptual consequences of oculomotor actions.

  14. Controlled delivery of antiangiogenic drug to human eye tissue using a MEMS device

    KAUST Repository

    Pirmoradi, Fatemeh Nazly

    2013-01-01

    We demonstrate an implantable MEMS drug delivery device to conduct controlled and on-demand, ex vivo drug transport to human eye tissue. Remotely operated drug delivery to human post-mortem eyes was performed via a MEMS device. The developed curved packaging cover conforms to the eyeball thereby preventing the eye tissue from contacting the actuating membrane. By pulsed operation of the device, using an externally applied magnetic field, the drug released from the device accumulates in a cavity adjacent to the tissue. As such, docetaxel (DTX), an antiangiogenic drug, diffuses through the eye tissue, from sclera and choroid to retina. DTX uptake by sclera and choroid were measured to be 1.93±0.66 and 7.24±0.37 μg/g tissue, respectively, after two hours in pulsed operation mode (10s on/off cycles) at 23°C. During this period, a total amount of 192 ng DTX diffused into the exposed tissue. This MEMS device shows great potential for the treatment of ocular posterior segment diseases such as diabetic retinopathy by introducing a novel way of drug administration to the eye. © 2013 IEEE.

  15. Two eyes, one vision: binocular motion perception in human visual cortex

    NARCIS (Netherlands)

    Barendregt, M.

    2016-01-01

    An important aspect of human vision is the fact that it is binocular, i.e. that we have two eyes. As a result, the brain nearly always receives two slightly different images of the same visual scene. Yet, we only perceive a single image and thus our brain has to actively combine the binocular visual

  16. Different cellular effects of four anti-inflammatory eye drops on human corneal epithelial cells: independent in active components.

    Science.gov (United States)

    Qu, Mingli; Wang, Yao; Yang, Lingling; Zhou, Qingjun

    2011-01-01

    To evaluate and compare the cellular effects of four commercially available anti-inflammatory eye drops and their active components on human corneal epithelial cells (HCECs) in vitro. The cellular effects of four eye drops (Bromfenac Sodium Hydrate Eye Drops, Pranoprofen Eye Drops, Diclofenac Sodium Eye Drops, and Tobramycin & Dex Eye Drops) and their corresponding active components were evaluated in an HCEC line with five in vitro assays. Cell proliferation and migration were measured using 3-(4,5)-dimethylthiahiazo (-z-y1)-3 5-di-phenytetrazoliumromide (MTT) assay and transwell migration assay. Cell damage was determined with the lactate dehydrogenase (LDH) assay. Cell viability and median lethal time (LT₅₀) were measured by 7-amino-actinomycin D (7-AAD) staining and flow cytometry analysis. Cellular effects after exposure of HCECs to the four anti-inflammatory eye drops were concentration dependent. The differences of cellular toxicity on cell proliferation became significant at lower concentrations (Eye Drops showed significant increasing effects on cell damage and viability when compared with the other three solutions. Tobramycin & Dex Eye Drops inhibited the migration of HCECs significantly. Tobramycin & Dex Eye Drops showed the quickest effect on cell viability: the LT₅₀ was 3.28, 9.23, 10.38, and 23.80 min for Tobramycin & Dex Eye Drops, Diclofenac Sodium Eye Drops, Pranoprofen Eye Drops, and Bromfenac Sodium Hydrate Eye Drops, respectively. However, the comparisons of cellular toxicity revealed significant differences between the eye drops and their active components under the same concentration. The corneal epithelial toxicity differences among the active components of the four eye drops became significant as higher concentration (>0.020%). The four anti-inflammatory eye drops showed different cellular effects on HCECs, and the toxicity was not related with their active components, which provides new reference for the clinical application and drug

  17. The neurophysiology of human touch and eye gaze and its effects on therapeutic relationships and healing: a scoping review protocol.

    Science.gov (United States)

    Kerr, Fiona; Wiechula, Rick; Feo, Rebecca; Schultz, Tim; Kitson, Alison

    2016-04-01

    The objective of this scoping review is to examine and map the range of neurophysiological impacts of human touch and eye gaze, and better understand their possible links to the therapeutic relationship and the process of healing. The specific question is "what neurophysiological impacts of human touch and eye gaze have been reported in relation to therapeutic relationships and healing?"

  18. Hp(3)/Φ conversion coefficients for neutrons: discussion on the basis of the new ICRP recommended limit for the eye lens

    International Nuclear Information System (INIS)

    Ferrari, P.; Gualdrini, G.; Fantuzzi, E.; Tanner, R.

    2014-01-01

    The new recommendation issued by the International Commission on Radiological Protection (ICRP) introducing a 20-mSv annual dose limit for the eye lens stimulated an interesting debate among the radiation protection community. In the present work the problem of estimating H p (3) for neutron realistic workplace spectra is treated, employing the recently published H p (3)/Φ conversion coefficients with the aim of establishing a workplace-dependent relationship between H p (10) and H p (3). The results demonstrate that, whilst the two quantities can differ by less than 10 %, in general, H p (10) cannot be considered a conservative estimate of H p (3). The present study was conducted to find out whether it is possible to derive H p (3) from H p (10) measurements/determinations in neutron workplace fields using the relationship that can be established between the conversion coefficients H p (3)/Φ and H p (10)/Φ evaluated for monoenergetic neutron beams. Several real cases, taken from the IAEA neutron source compendium, were investigated and, in general, it can be conclude that H p (10) is seldom a conservative estimate of H p (3) (only at 0 deg. and in one case, among the treated spectra, H p (10)/Φ is higher than H p (3)/Φ). Indeed, care should be taken if one tries to derive directly such a correction factor from tabulations of neutron monoenergetic plots of conversion coefficients, on the basis of the mean energy, because in case of really degraded spectra (as in the heavy shielded situation) the mean energy, as expected, could be a too rough a parameter. However, in general, for 0 deg., antero-posterior irradiation condition, which is expected to be a quite common working condition, H p (10) underestimation is of the order of 10 % thus, at least, a correction factor of 1.1 should be applied to H p (10) in order to estimate the 'corresponding' H p (3). For irradiation conditions far from the normal incidence for which the underestimation can be as high as 60

  19. Corneal cell adhesion to contact lens hydrogel materials enhanced via tear film protein deposition.

    Directory of Open Access Journals (Sweden)

    Claire M Elkins

    Full Text Available Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS, borate buffered saline (BBS, or Sensitive Eyes Plus Saline Solution (Sensitive Eyes, either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.

  20. Clinical light damage to the eye

    International Nuclear Information System (INIS)

    Miller, D.

    1987-01-01

    This book contains four sections: The Nature of Light and of Light Damage to Biological Tissues; Light Damage to the Eye; Protecting the Eye from Light Damage; and Overview of Light Damage to the Eye. Some of the paper titles are: Ultraviolet-Absorbing Intraocular Lens Implants; Phototoxic Changes in the Retina; Light Damage to the Lens; and Radiation, Light, and Sight

  1. Light-focusing human micro-lenses generated from pluripotent stem cells model lens development and drug-induced cataract in vitro.

    Science.gov (United States)

    Murphy, Patricia; Kabir, Md Humayun; Srivastava, Tarini; Mason, Michele E; Dewi, Chitra U; Lim, Seakcheng; Yang, Andrian; Djordjevic, Djordje; Killingsworth, Murray C; Ho, Joshua W K; Harman, David G; O'Connor, Michael D

    2018-01-09

    Cataracts cause vision loss and blindness by impairing the ability of the ocular lens to focus light onto the retina. Various cataract risk factors have been identified, including drug treatments, age, smoking and diabetes. However, the molecular events responsible for these different forms of cataract are ill-defined, and the advent of modern cataract surgery in the 1960s virtually eliminated access to human lenses for research. Here, we demonstrate large-scale production of light-focusing human micro-lenses from spheroidal masses of human lens epithelial cells purified from differentiating pluripotent stem cells. The purified lens cells and micro-lenses display similar morphology, cellular arrangement, mRNA expression and protein expression to human lens cells and lenses. Exposing the micro-lenses to the emergent cystic fibrosis drug Vx-770 reduces micro-lens transparency and focusing ability. These human micro-lenses provide a powerful and large-scale platform for defining molecular disease mechanisms caused by cataract risk factors, for anti-cataract drug screening and for clinically relevant toxicity assays. © 2018. Published by The Company of Biologists Ltd.

  2. Analysis of the speckle properties in a laser projection system based on a human eye model.

    Science.gov (United States)

    Cui, Zhe; Wang, Anting; Ma, Qianli; Ming, Hai

    2014-03-01

    In this paper, the properties of the speckle that is observed by humans in laser projection systems are theoretically analyzed. The speckle pattern on the fovea of the human retina is numerically simulated by introducing a chromatic human eye model. The results show that the speckle contrast experienced by humans is affected by the light intensity of the projected images and the wavelength of the laser source when considering the paracentral vision. Furthermore, the image quality is also affected by these two parameters. We believe that these results are useful for evaluating the speckle noise in laser projection systems.

  3. Xanthophylls and alpha-tocopherol decrease UVB-induced lipid peroxidation and stress signaling in human lens epithelial cells.

    Science.gov (United States)

    Chitchumroonchokchai, Chureeporn; Bomser, Joshua A; Glamm, Jayme E; Failla, Mark L

    2004-12-01

    Epidemiological studies suggest that consumption of vegetables rich in the xanthophylls lutein (LUT) and zeaxanthin (ZEA) reduces the risk for developing age-related cataract, a leading cause of vision loss. Although LUT and ZEA are the only dietary carotenoids present in the lens, direct evidence for their photoprotective effect in this organ is not available. The present study examined the effects of xanthophylls and alpha-tocopherol (alpha-TC) on lipid peroxidation and the mitogen-activated stress signaling pathways in human lens epithelial (HLE) cells following ultraviolet B light (UVB) irradiation. When presented with LUT, ZEA, astaxanthin (AST), and alpha-TC as methyl-beta-cyclodextrin complexes, HLE cells accumulated the lipophiles in a concentration- and time-dependent manner with uptake of LUT exceeding that of ZEA and AST. Pretreatment of cultures with either 2 micromol/L xanthophyll or 10 micromol/L alpha-TC for 4 h before exposure to 300 J/m(2) UVB radiation decreased lipid peroxidation by 47-57% compared with UVB-treated control HLE cells. Pretreatment with the xanthophylls and alpha-TC also inhibited UVB-induced activation of c-JUN NH(2)-terminal kinase (JNK) and p38 by 50-60 and 25-32%, respectively. There was substantial inhibition of UVB-induced JNK and p38 activation for cells containing xanthophylls/mg, respectively, whereas >2.3 nmol alpha-TC/mg protein was required to significantly decrease UVB-induced stress signaling. These data suggest that xanthophylls are more potent than alpha-TC for protecting human lens epithelial cells against UVB insult.

  4. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... have given blind patients some functional vision, using human embryonic stem cells. Two blind patients regained enough sight to read again after getting stem cell implants in their damaged eyes. ... EyeSmart Resources for Professionals Link your website to EyeSmart Embed ...

  5. Colored Contact Lens Dangers

    Medline Plus

    Full Text Available ... Thomas Steinemann, MD, professor of ophthalmology at Case Western Reserve University in Cleveland. "This is far from ... technologies aiming to fix failing eye parts with human-made versions. U.S. News Highlights the Value of Ophthalmologists APR 20, ... EyeSmart Resources for Professionals Link your website to EyeSmart Embed ...

  6. The effects of ultraviolet-A radiation on visual evoked potentials in the young human eye

    International Nuclear Information System (INIS)

    Sanford, B.E.; Beacham, S.; Hanifin, J.P.; Hannon, P.; Streletz, L.; Sliney, D.; Brainard, G.C.

    1996-01-01

    A recent study from this laboratory using visual evoked potentials (VEPs) demonstrated that children's eyes are capable of detecting ultraviolet radiation. The aim of this study was to compare dose-response relationships in two age groups, 6-10 years (n=10) and 20-25 years (n=10). Under photopic viewing conditions (550 lux), exposures of monochromatic UV-A (339 nm) and visible radiation (502 nm) were correlated to VEPs. The results demonstrate that monochromatic UV-A can elicit age and dose dependent responses in the human visual system, suggesting that the eyes of children are more responsive to UV stimuli than the eyes of young adults. (au) 17 refs

  7. Objective measurement of intraocular forward light scatter using Hartmann-Shack spot patterns from clinical aberrometers. Model-eye and human-eye study.

    Science.gov (United States)

    Cerviño, Alejandro; Bansal, Dheeraj; Hosking, Sarah L; Montés-Micó, Robert

    2008-07-01

    To apply software-based image-analysis tools to objectively determine intraocular scatter determined from clinically derived Hartmann-Shack patterns. Aston Academy of Life Sciences, Aston University, Birmingham, United Kingdom, and Department of Optics, University of Valencia, Valencia, Spain. Purpose-designed image-analysis software was used to quantify scatter from centroid patterns obtained using a clinical Hartmann-Shack analyzer (WASCA, Zeiss/Meditec). Three scatter values, as the maximum standard deviation within a lenslet for all lenslets in the pattern, were obtained in 6 model eyes and 10 human eyes. In the model-eye sample, patterns were obtained in 4 sessions: 2 without realigning between measurements, 1 with realignment, and 1 with an angular shift of 6 degrees from the instrument axis. Three measurements were made in the human eyes with the C-Quant straylight meter (Oculus) to obtain psychometric and objective measures of retinal straylight. Analysis of variance, intraclass correlation coefficients, coefficient of repeatability (CoR), and correlations were used to determine intrasession and intersession repeatability and the relationship between measures. No significant differences were found between the sessions in the model eye (P=.234). The mean CoR was less than 10% in all model- and human-eye sessions. After incomplete patterns were removed, good correlation was achieved between psychometric and objective scatter measurements despite the small sample size (n=6; r=-0.831; P=.040). The methodology was repeatable in model and human eyes, strong against realignment and misalignment, and sensitive. Clinical application would benefit from effective use of the sensor's dynamic range.

  8. Modeling the influence of LASIK surgery on optical properties of the human eye

    Science.gov (United States)

    Szul-Pietrzak, Elżbieta; Hachoł, Andrzej; Cieślak, Krzysztof; Drożdż, Ryszard; Podbielska, Halina

    2011-11-01

    The aim was to model the influence of LASIK surgery on the optical parameters of the human eye and to ascertain which factors besides t