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Sample records for monocular visual acuity

  1. Peculiarities of vernier monocular and binocular visual acuity in the retinal orthogonal meridians in patients with hypermetropic astigmatism

    Directory of Open Access Journals (Sweden)

    Владимир Александрович Коломиец

    2015-06-01

    Full Text Available It was carried out an examination of meridional vernier visual acuity in 100 patients 7-25 years old with a simple and compound hypermetropic astigmatism and refractive ambyiopia. An astigmatic component of refraction was in range 0,5- 2,5 dptr. Visual acuity on the sighting eyes after correction was 0,9- 1,0, on eyes with amblyopia 0,4 - 0,85 relative units.Methods. Visual acuity was defined by the Landolt rings of Sivtsev table. Vernier visual acuity was defined in seconds of arc from 5 km, using special computer program.Result. It was demonstrated that in patients with the simple hypertropic astigmatism diagnosis of meridional amblyopia can be specified by the comparison of data of monocular and binocular vernier visual acuity in orthogonal meridians of retinas.Conclusions. An effect of the rise of meridional binocular visual acuity in one of meridians and its absence in another one allows define selective meridional disturbances of the visual acuity

  2. Visual acuity test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003396.htm Visual acuity test To use the sharing features on this page, please enable JavaScript. The visual acuity test is used to determine the smallest ...

  3. Monocular visual ranging

    Science.gov (United States)

    Witus, Gary; Hunt, Shawn

    2008-04-01

    The vision system of a mobile robot for checkpoint and perimeter security inspection performs multiple functions: providing surveillance video, providing high resolution still images, and providing video for semi-autonomous visual navigation. Mid-priced commercial digital cameras support the primary inspection functions. Semi-autonomous visual navigation is a tertiary function whose purpose is to reduce the burden of teleoperation and free the security personnel for their primary functions. Approaches to robot visual navigation require some form of depth perception for speed control to prevent the robot from colliding with objects. In this paper present the initial results of an exploration of the capabilities and limitations of using a single monocular commercial digital camera for depth perception. Our approach combines complementary methods in alternating stationary and moving behaviors. When the platform is stationary, it computes a range image from differential blur in the image stack collected at multiple focus settings. When the robot is moving, it extracts an estimate of range from the camera auto-focus function, and combines this with an estimate derived from angular expansion of a constellation of visual tracking points.

  4. [Snellen visual acuity evaluation].

    Science.gov (United States)

    Zapparoli, Marcio; Klein, Fernando; Moreira, Hamilton

    2009-01-01

    To evaluate the visual acuity (VA) measurement by Snellen chart at three main Ophthalmology centers in Curitiba, compare these measurements with a computerized method for calibrating VA and also with the standard theory developed by Hermann Snellen. Descriptive study including 15 Ophthalmology clinics and a computerized method to measure the VA. Using a tape measure and a caliper, measurement of the distance was obtained from the sitting patients' eye to VA optotypes projection on the wall. At the same time, measurement of the size of the letters of 4 lines of the VA projection on the wall was performed. To analyze the results, it was opted to compare the angles presented by each clinic for each measurement. It was not surprising that no clinic presented an exact angle of 5 arch minutes. Comparing clinics results with computerized method, we observed that only 2 clinics obtained better results if compared with the angles obtained from optotypes projection, but the data is very similar and with no statistical significance. In relation to the other clinics, the superiority of the computerized method is very relevant. All had differences in comparison to the gold standard. Individually, comparing computerized method to standard Snellen theory, it was observed that a condition very close to the ideal was obtained, in other words, results very similar to 5 arch minutes were noted in all the visual acuities analyzed. It can be concluded that there is a great heterogeneity in the evaluation of VA in different Ophthalmology centers. Also, the same patient, evaluated in different clinics, can obtain different VA measurements. The computerized method is practical, portable, adjustable for different distances, and maintains optotypes proportionality ratio based on visual angle and approaches the theoretical values recommended by Herman Snellen in 1862.

  5. The neurology of visual acuity.

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    Frisén, L

    1980-09-01

    A series of patients with well defined lesions of various parts of the visual pathways was studied in an attempt to iluminate the neuropathophysiology of visual acuity. Acuity was found to remain normal in all cases with unilateral retrochiasmal lesions, including those of the optic tract. Bilateral retrochiasmal lesions involving the foveal nerve fibres on both sides impaired acuity to the same degree in both eyes. Lateral chiasmal lesions regularly produced impaired acuity in the ipsilateral eye. Midchiasmal lesions commonly led to an impairment of visual acuity in both eyes, usually asymmetrically, and roughly proportionate to the severity of the visual field defect. Compression optic neuropathy was found to reduce acuity in rough proportion to the severity of compression. It was concluded that acuity remains normal as long as either the crossing or the non-crossing neural outflow from the retinal fovea remains intact: acuity fails only when both sets of nerve fibres are compromised. A properly executed acuity test seems to be a powerful tool for detecting such conditions. The lower limit of normal acuity should never be set below 1.0 or 20/20: even this level is clearly subnormal in many subjects.

  6. Does monocular visual space contain planes?

    NARCIS (Netherlands)

    Koenderink, J.J.; Albertazzi, L.; Doorn, A.J. van; Ee, R. van; Grind, W.A. van de; Kappers, A.M.L.; Lappin, J.S.; Norman, J.F.; Oomes, A.H.J.; Pas, S.F. te; Phillips, F.; Pont, S.C.; Richards, W.A.; Todd, J.T.; Verstraten, F.A.J.; Vries, S.C. de

    2010-01-01

    The issue of the existence of planes—understood as the carriers of a nexus of straight lines—in the monocular visual space of a stationary human observer has never been addressed. The most recent empirical data apply to binocular visual space and date from the 1960s (Foley, 1964). This appears to be

  7. 38 CFR 4.76 - Visual acuity.

    Science.gov (United States)

    2010-07-01

    ... DISABILITIES Disability Ratings The Organs of Special Sense § 4.76 Visual acuity. (a) Examination of visual... distance and near vision using Snellen's test type or its equivalent. (b) Evaluation of visual acuity. (1) Evaluate central visual acuity on the basis of corrected distance vision with central fixation, even if...

  8. Age norms for monocular grating acuity measured by sweep-VEP in the first three years of age Estudo normativo de acuidade visual de resolução de grades medido pelo PVE de varredura nos três primeiros anos de vida

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    Solange Rios Salomão

    2008-08-01

    Full Text Available PURPOSE: To determine age norms for grating visual acuity and interocular acuity differences measured by the sweep-visually evoked potentials (VEP technique in the first three years of life. METHODS: Monocular grating visual acuity was measured using the sweep-VEP in 67 healthy normal infants and children in the first 36 months of life. RESULTS: Sweep-VEP grating acuity ranged from 0.80 logMAR (20/125 Snellen equivalent in the first month of life to 0.06 logMAR (20/20 Snellen equivalent at 36 months of age. Lower normal limits (95th percentile limit ranged from 0.95 logMAR (20/180 to 0.12 logMAR (20/25 with a progression of approximately 3 octaves in the first 36 months of age. The largest acceptable interocular acuity difference for clinical purposes was 0.10 logMAR. CONCLUSIONS: Age norms for grating acuity along with interocular acuity differences were determined using the sweep-VEP technique. These norms should be incorporated in clinical practice for precise diagnosis of visual status in infants and preverbal children.OBJETIVOS: Propor valores normativos de acuidade visual de grades e sua respectiva diferença interocular medidas pelo potencial visual evocado de varredura nos primeiros três anos de vida. MÉTODOS: Foram avaliadas 67 crianças sadias, sem doenças oculares, que tiveram a acuidade visual medida pelos potenciais evocados visuais de varredura. RESULTADOS: A acuidade visual média variou de 0,80 logMAR (equivalente de Snellen de 20/125 no primeiro mês de vida a 0,06 logMAR (equivalente de Snellen de 20/20 aos 36 meses. Os limites normais inferiores (percentil 95% variaram de 0,95 logMAR (20/180 a 0,12 logMAR (20/25 com progressão de aproximadamente 3 oitavas nos primeiros 36 meses de vida. A diferença interocular máxima aceitável foi de 0,10 logMAR. CONCLUSÕES: Os valores normativos de acuidade visual e de diferença interocular de acuidade foram obtidos pela técnica do potencial visual evocado de varredura. Prop

  9. Grating visual acuity with Teller cards compared with Snellen visual acuity in literate patients.

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    Kushner, B J; Lucchese, N J; Morton, G V

    1995-04-01

    To determine the usefulness of Teller Acuity Cards for detecting three levels of vision deficit, the cutoff for amblyopia (20/40 or poorer), vision impairment (20/70), or legal blindness (20/200). We compared grating visual acuity with the Teller cards with Snellen visual acuity (our gold standard) in 69 literate patients with amblyopia or other cause of vision loss in a prospective masked study. Teller card visual acuity and distance Snellen visual acuity correlated significantly (r = .508, P Snellen visual acuity. Teller card visual acuity had a low sensitivity for detecting vision deficit of 20/40 or poorer (58%), vision deficit of 20/70 or poorer (39%), or legal blindness (24%), but somewhat more accurately reflected near Snellen visual acuity than distance visual Snellen acuity. Teller cards had a higher positive predictive value--80% for 20/70 visual acuity and 43% for legal blindness, as determined by near Snellen visual acuity. Specificity of Teller cards was 88% for detecting visual acuity loss of 20/70 and 98% for legal blindness. Negative predictive value of Teller cards for detecting visual acuity loss of 20/70 was 50% and for legal blindness was 71%. Teller Acuity Cards may underestimate the presence of amblyopia of all types, legal blindness, and a specified level of vision impairment (20/70). Even in the presence of normal visual acuity measurements with Teller cards, significant visual loss as assessed by standard Snellen optotypes may be anticipated in many patients.

  10. Visual SLAM for Handheld Monocular Endoscope.

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    Grasa, Óscar G; Bernal, Ernesto; Casado, Santiago; Gil, Ismael; Montiel, J M M

    2014-01-01

    Simultaneous localization and mapping (SLAM) methods provide real-time estimation of 3-D models from the sole input of a handheld camera, routinely in mobile robotics scenarios. Medical endoscopic sequences mimic a robotic scenario in which a handheld camera (monocular endoscope) moves along an unknown trajectory while observing an unknown cavity. However, the feasibility and accuracy of SLAM methods have not been extensively validated with human in vivo image sequences. In this work, we propose a monocular visual SLAM algorithm tailored to deal with medical image sequences in order to provide an up-to-scale 3-D map of the observed cavity and the endoscope trajectory at frame rate. The algorithm is validated over synthetic data and human in vivo sequences corresponding to 15 laparoscopic hernioplasties where accurate ground-truth distances are available. It can be concluded that the proposed procedure is: 1) noninvasive, because only a standard monocular endoscope and a surgical tool are used; 2) convenient, because only a hand-controlled exploratory motion is needed; 3) fast, because the algorithm provides the 3-D map and the trajectory in real time; 4) accurate, because it has been validated with respect to ground-truth; and 5) robust to inter-patient variability, because it has performed successfully over the validation sequences.

  11. Adaptive Rendering Based on Visual Acuity Equations

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new method of adaptable rendering for interaction in Virtual Environment(VE) through different visual acuity equations is proposed. An acuity factor equation of luminance vision is first given. Secondly, five equations which calculate the visual acuity through visual acuity factors are presented, and adaptive rendering strategy based on different visual acuity equations is given. The VE system may select one of them on the basis of the host's load, hereby select LOD for each model which would be rendered. A coarser LOD is selected where the visual acuity is lower, and a better LOD is used where it is higher. This method is tested through experiments and the experimental results show that it is effective.

  12. Visual Acuity Reporting in Clinical Research Publications.

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    Tsou, Brittany C; Bressler, Neil M

    2017-06-01

    Visual acuity results in publications typically are reported in Snellen or non-Snellen formats or both. A study in 2011 suggested that many ophthalmologists do not understand non-Snellen formats, such as logarithm of the Minimum Angle of Resolution (logMAR) or Early Treatment Diabetic Retinopathy Study (ETDRS) letter scores. As a result, some journals, since at least 2013, have instructed authors to provide approximate Snellen equivalents next to non-Snellen visual acuity values. To evaluate how authors currently report visual acuity and whether they provide Snellen equivalents when their reports include non-Snellen formats. From November 21, 2016, through December 14, 2016, one reviewer evaluated visual acuity reporting among all articles published in 4 ophthalmology clinical journals from November 2015 through October 2016, including 3 of 4 journals that instructed authors to provide Snellen equivalents for visual acuity reported in non-Snellen formats. Frequency of formats of visual acuity reporting and frequency of providing Snellen equivalents when non-Snellen formats are given. The 4 journals reviewed had the second, fourth, fifth, and ninth highest impact factors for ophthalmology journals in 2015. Of 1881 articles reviewed, 807 (42.9%) provided a visual acuity measurement. Of these, 396 (49.1%) used only a Snellen format; 411 (50.9%) used a non-Snellen format. Among those using a non-Snellen format, 145 (35.3%) provided a Snellen equivalent while 266 (64.7%) provided only a non-Snellen format. More than half of all articles in 4 ophthalmology clinical journals fail to provide a Snellen equivalent when visual acuity is not in a Snellen format. Since many US ophthalmologists may not comprehend non-Snellen formats easily, these data suggest that editors and publishing staff should encourage authors to provide Snellen equivalents whenever visual acuity data are reported in a non-Snellen format to improve ease of understanding visual acuity measurements.

  13. The importance of measuring dynamic visual acuity

    National Research Council Canada - National Science Library

    Muzdalo, Natasa Vujko

    2013-01-01

    .... Beside good eyesight, drivers also have to have good reflexes and short reaction span. The aim of this study was to compare dynamic and static visual acuity in order to observe how they vary among individuals...

  14. Estimating visual acuity by character counting using the Snellen visual acuity chart.

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    Levy, A H; McCulley, T J; Lam, B L; Feuer, W J

    2005-06-01

    This study examines visual acuity estimation with character counting, which can be used in subjects with nonorganic visual loss. The right eyes of 35 healthy subjects were fogged with plus lenses and tested with the Snellen visual acuity chart (Reichert 11180). Visual acuity and counting level were assessed under various degrees of fogging, up to a maximal fogged acuity of 20/200. Counting level was defined as the smallest line that subjects could count the number of characters correctly. For each counting level, the visual acuity that 95% of subjects could see equal to or better than was determined. A counting level of 20/10 estimates (ie 95% chance) a visual acuity equal to or better than 20/30. Counting levels 20/15, 20/20, and 20/25 estimate visual acuities of at least 20/50, 20/80, and 20/80, respectively. Counting levels 20/30-20/60 estimate a visual acuity of at least 20/200. Character counting appears to be a useful technique of obtaining a rough estimate of visual acuity in subjects unable to be tested by standard methods, such as those with non-organic visual loss.

  15. [Some basic aspects in statistical analysis of visual acuity data].

    Science.gov (United States)

    Ren, Ze-Qin

    2007-06-01

    All visual acuity charts used currently have their own shortcomings. Therefore, it is difficult for ophthalmologists to evaluate visual acuity data. Many problems present in the use of statistical methods for handling visual acuity data in clinical research. The quantitative relationship between visual acuity and visual angle varied in different visual acuity charts. The type of visual acuity and visual angle are different from each other. Therefore, different statistical methods should be used for different data sources. A correct understanding and analysis of visual acuity data could be obtained only after the elucidation of these aspects.

  16. Relationship of Visual Cortex Function and Visual Acuity in Anisometropic Amblyopic Children

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    Chuanming Li, Lin Cheng, Qiongwu Yu, Bing Xie, Jian Wang

    2012-01-01

    Full Text Available Purpose: To detect the functional deficit of the visual cortex in anisometropic amblyopia children using functional magnetic resonance imaging (fMRI technique, and investigate the relationship between visual acuity and visual cortex function.Methods: Blood oxygenation level-dependent fMRI (BOLD-fMRI was performed in ten monocular anisometropic amblyopia children and ten normal controls. fMRI images were acquired in two runs with visual stimulation delivered separately through the sound and amblyopic eyes. Measurements were performed in cortical activation of striate and extrastriate areas at the occipital lobe. The relationship between cortex function and visual acuity was analyzed by Pearson partial analysis.Results: The activation areas of both the striate and extrastriate cortices in the amblyopic eyes were significantly lower than that of the sound fellow eyes. No relationship was found between the striate and extrastriate cortex activation. No relationship was found between the visual cortical activation of striate, extrastriate areas and visual acuity of anisometropic amblyopes.Conclusions: BOLD-fMRI revealed the independent striate and extrastriate cortical deficits in anisometropic amblyopes. In addition, the visual acuity lesion and the striate and extrastriate cortical deficits were not parallel, and results of fMRI examination have much potential value in the evaluation of amblyopia.

  17. Development of visual acuity in children with cerebral visual impairment.

    Science.gov (United States)

    Lim, Mira; Soul, Janet S; Hansen, Ronald M; Mayer, D Luisa; Moskowitz, Anne; Fulton, Anne B

    2005-09-01

    To study the development of visual acuity in term-born children with cerebral visual impairment and a history of neonatal hypoxic-ischemic encephalopathy. We studied 19 term-born children, aged 6 months to 6 years, with moderate to severe neonatal hypoxic-ischemic encephalopathy and behaviors indicative of cerebral visual impairment. Longitudinal measures of grating acuity were obtained using preferential looking (PL) and visual evoked potential (VEP) procedures. Visual acuities at first and last visits were compared. The courses of acuity development in the 9 children who underwent both VEP and PL acuity assessment at 4 or more ages were compared with normal development. All children had measurable PL and VEP acuity, despite poor visual behavior. In nearly all, both PL and VEP acuity were below normal for age. For both PL and VEP measures, acuity at the last visit was, on average, 1 octave better than at the first visit, with a rate of improvement lower than normal. Although parallel courses of PL and VEP development occurred in many, substantial disparities in PL and VEP acuity were observed in others. Modest increases in PL and VEP grating acuity occur during early childhood in many of these patients. The rate of increase is lower than normal.

  18. Comparing visual acuity in preschool children using the Lea symbols and Sheridan Gardiner charts

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    Aghafekokhian B. Osaiyuwu

    2015-03-01

    Full Text Available Visual acuity measurement is a vital part of an optometric examination. The purpose of the present study was to compare visual acuity in preschool children using two charts – the Lea symbols chart and the Sheridan Gardiner chart. One hundred and fifty-three preschool children (72 boys and 81 girls between the ages of 3 and 5 years (mean age and standard deviation 4.23 ± 0.78 years were recruited from five randomly selected nursery schools. Distance visual acuity was measured monocularly and binocularly after a pre-test was done. An interval of 5 minutes was allowed for testing with both charts. The ages and sexes of each child were documented. Results showed a statistical difference in visual acuities using both charts (p < 0.05. There was also a statistical difference in both charts regarding age. There was no significant gender difference between the results from each chart.

  19. VISUAL ACUITY IN DIFFERENT INTENSITIES OF LIGHT

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    Shruthi

    2014-12-01

    Full Text Available : BACKGROUND: Visual acuity is the resolving power of eyes which enables to distinguish the details and shapes of the objects. It is influenced by the intensity (illumination of light falling on the object. Measuring visual acuity is a simple test in assessing-health of the eyes, the pathway and visual brain. Intact normal vision is mandatory for selection of posts related to driving and traffic services. Intactness of visual acuity is influenced by a number of factors and one among them is intensity of ambient light. Hence, this study is undertaken to assess optimum light intensity for better visual perception. AIM: To evaluate the association between visual acuity and intensity of light and the optimum intensity of light to carry out for better perception of vision. MATERIALS AND METHODS: 100 literate subjects - 50 males and 50 females between 15-45 years, act both as cases and controls. Subjects, instructed to read alphabets and numbers from Snellen chart in 15 watts, 20 watts, 40 watts, 60 watts, 100 watts, 200 watts were considered as the study group and the same subjects in this study in day light as controls. Chart was placed at 6m distance. Both right and left eyes were tested separately in dark room illuminated with controlled light intensities. Number of correct characters read were noted for different illuminations and compared with that of controls. RESULTS: Reduced illumination significantly increased the no of incorrect choices and was statistically significant (P < 0.05 between 15 - 100 W. Visual acuity was best in 200 W in comparison with day light but was not statistically significant. However Visual acuity showed no significant difference between males and females for different intensities of light.

  20. Monocular Visual Deprivation Suppresses Excitability in Adult Human Visual Cortex

    DEFF Research Database (Denmark)

    Lou, Astrid Rosenstand; Madsen, Kristoffer Hougaard; Paulson, Olaf Bjarne

    2011-01-01

    The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we...... employed TMS to trace plastic changes in adult visual cortex before, during, and after 48 h of monocular deprivation (MD) of the right dominant eye. In healthy adult volunteers, MD-induced changes in visual cortex excitability were probed with paired-pulse TMS applied to the left and right occipital cortex....... Stimulus–response curves were constructed by recording the intensity of the reported phosphenes evoked in the contralateral visual field at range of TMS intensities. Phosphene measurements revealed that MD produced a rapid and robust decrease in cortical excitability relative to a control condition without...

  1. The Development and Validation of a Smartphone Visual Acuity Test (Peek Acuity) for Clinical Practice and Community-Based Fieldwork

    Science.gov (United States)

    Bastawrous, Andrew; Rono, Hillary; Livingstone, Iain AT; Weiss, Helen A.; Jordan, Stewart; Kuper, Hannah; Burton, Matthew

    2017-01-01

    Importance Visual acuity is the most frequently performed measure of visual function in clinical practice and the majority of people worldwide living with visual impairment are living in low and middle-income countries Objective To design and validate a smartphone-based visual acuity test that is not dependent on familiarity with symbols or letters commonly used in the English language. Design Validation study comparing results from smartphone Peek Acuity to Snellen Acuity (clinical normal) and the Early Treatment Diabetic Retinopathy Study (ETDRS) LogMAR chart (reference standard). Setting This study was nested within the six-year follow-up of the Nakuru Eye Disease Cohort in central Kenya. Participants Three hundred adults aged 55 years and above, recruited consecutively from the Nakuru Eye Disease Cohort Study.. Main Outcome(s) and Measure(s) Outcome measures were monocular logarithm of the minimum angle of resolution (LogMAR) visual acuity scores for each test: ETDRS LogMAR, Snellen and Peek. Peek was compared, in terms of test-retest variability (TRV) and measurement time, with that of the Snellen and ETDRS LogMAR chart in participants’ homes and temporary clinic settings in rural Kenya in 2013/2014. Results The 95% confidence limits for TRV of smartphone acuity data were +/-0.033 LogMAR. The mean difference between smartphone and ETDRS and smartphone and Snellen acuity data was 0.07 (95%CI: 0.05-0.09) and 0.08 (95%CI: 0.06-0.10) LogMAR respectively indicating that smartphone acuities agreed well with those of the ETDRS chart and Snellen. The agreement of Peek and ETDRS was greater than Snellen with ETDRS, p=0.08 (95%CI 0.05 to 0.10). The local Kenyan community health care workers readily accepted the Peek Acuity smartphone test; it required minimal training and took no longer than Snellen; 77s vs. 82s (95%CI: 71 – 84s vs. 73 – 91s, p=0.13). Conclusions The study demonstrated that the Peek Acuity smartphone test is capable of accurate and repeatable

  2. How to measure distance visual acuity

    Directory of Open Access Journals (Sweden)

    Janet Marsden

    2014-04-01

    Full Text Available Visual acuity (VA is a measure of the ability of the eye to distinguish shapes and the details of objects at a given distance. It is important to assess VA in a consistent way in order to detect any changes in vision. One eye is tested at a time.

  3. New standardized visual acuity charts in hindi and gujarati

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    Khamar Bakulesh

    1996-01-01

    Full Text Available Conventional Snellen visual acuity chart has unequal difficulty score and irregular progression in letter size causing jumping effect at different visual acuity levels. There is also increase in number of letters from above downwards. Consequently one or two mistakes per line has different meaning of visual acuity at different levels. We designed a new visual acuity chart of fourteen lines in Hindi and Gujarati to facilitate standardization in visual acuity measurement. These charts are designed for use at six meter distance, and the illumination is provided from front. These charts provide a standardized way of measuring visual acuity using local languages.

  4. New standardized visual acuity charts in Hindi and Gujarati.

    Science.gov (United States)

    Khamar, B M; Vyas, U H; Desai, T M

    1996-09-01

    Conventional Snellen visual acuity chart has unequal difficulty score and irregular progression in letter size causing jumping effect at different visual acuity levels. There is also increase in number of letters from above downwards. Consequently one or two mistakes per line has different meaning of visual acuity at different levels. We designed a new visual acuity chart of fourteen lines in Hindi and Gujarati to facilitate standardization in visual acuity measurement. These charts are designed for use at six meter distance, and the illumination is provided from front. These charts provide a standardized way of measuring visual acuity using local languages.

  5. Visual Acuity Assessment in Persons with Dementia. Research Report

    Science.gov (United States)

    Morse, Alan R.; Teresi, Jeanne; Rosenthal, Bruce; Holmes, Douglas; Yatzkan, Elaine S.

    2004-01-01

    Most studies of vision in persons with Alzheimer's disease either exclude those with advanced dementia or are unable to assess their vision adequately, and therefore, improperly report these persons' visual acuity status. In this study, visual acuity was assessed using the ETDRS Snellen-type acuity chart and Teller Acuity Cards. The Teller Acuity…

  6. Altered anterior visual system development following early monocular enucleation

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    Krista R. Kelly

    2014-01-01

    Conclusions: The novel finding of an asymmetry in morphology of the anterior visual system following long-term survival from early monocular enucleation indicates altered postnatal visual development. Possible mechanisms behind this altered development include recruitment of deafferented cells by crossing nasal fibres and/or geniculate cell retention via feedback from primary visual cortex. These data highlight the importance of balanced binocular input during postnatal maturation for typical anterior visual system morphology.

  7. THE VISUAL ACUITY OF THE HONEY BEE.

    Science.gov (United States)

    Hecht, S; Wolf, E

    1929-07-20

    1. Bees respond by a characteristic reflex to a movement in their visual field. By confining the field to a series of parallel dark and luminous bars it is possible to determine the size of bar to which the bees respond under different conditions and in this way to measure the resolving power or visual acuity of the eye. The maximum visual acuity of the bee is lower than the lowest human visual acuity. Under similar, maximal conditions the fineness of resolution of the human eye is about 100 times that of the bee. 2. The eye of the bee is a mosaic composed of hexagonal pyramids of variable apical angle. The size of this angle determines the angular separation between adjacent ommatidia and therefore sets the structural limits to the resolving power of the eye. It is found that the visual angle corresponding to the maximum visual acuity as found experimentally is identical with the structural angular separation of adjacent ommatidia in the region of maximum density of ommatidia population. When this region of maximum ommatidia population is rendered non-functional by being covered with an opaque paint, the maximum visual acuity then corresponds to the angular separation of those remaining ommatidia which now constitute the maximum density of population. 3. The angular separation of adjacent ommatidia is much smaller in the vertical (dorso-ventral) axis than in the horizontal (anterio-posterior) axis. The experimentally found visual acuity varies correspondingly. From this and other experiments as well as from the shape of the eye itself, it is shown that the bee's eye is essentially an instrument for uni-directional visual resolution, functional along the dorso-ventral axis. The resolution of the visual pattern is therefore determined by the vertical angular separation of those ocular elements situated in the region of maximum density of ommatidia population. 4. The visual acuity of the bee varies with the illumination in much the same way that it does for the human

  8. Acuity-independent effects of visual deprivation on human visual cortex.

    Science.gov (United States)

    Hou, Chuan; Pettet, Mark W; Norcia, Anthony M

    2014-07-29

    Visual development depends on sensory input during an early developmental critical period. Deviation of the pointing direction of the two eyes (strabismus) or chronic optical blur (anisometropia) separately and together can disrupt the formation of normal binocular interactions and the development of spatial processing, leading to a loss of stereopsis and visual acuity known as amblyopia. To shed new light on how these two different forms of visual deprivation affect the development of visual cortex, we used event-related potentials (ERPs) to study the temporal evolution of visual responses in patients who had experienced either strabismus or anisometropia early in life. To make a specific statement about the locus of deprivation effects, we took advantage of a stimulation paradigm in which we could measure deprivation effects that arise either before or after a configuration-specific response to illusory contours (ICs). Extraction of ICs is known to first occur in extrastriate visual areas. Our ERP measurements indicate that deprivation via strabismus affects both the early part of the evoked response that occurs before ICs are formed as well as the later IC-selective response. Importantly, these effects are found in the normal-acuity nonamblyopic eyes of strabismic amblyopes and in both eyes of strabismic patients without amblyopia. The nonamblyopic eyes of anisometropic amblyopes, by contrast, are normal. Our results indicate that beyond the well-known effects of strabismus on the development of normal binocularity, it also affects the early stages of monocular feature processing in an acuity-independent fashion.

  9. [The best corrected presenting distance visual acuity in forensic medicine].

    Science.gov (United States)

    Liu, Rui-Jue

    2011-06-01

    At present the sight impairment evaluation in forensic medicine of China is based on the international classification of disease by WHO in 1973. The main measured indicator is "best corrected visual acuity". It is different from "presenting distance visual acuity" in some situations. In the new blindness and vision loss classification made by WHO in 2003, "presenting distance visual acuity" took the place of the "best corrected visual acuity". In the practice of forensic medicine, "presenting distance visual acuity" can not reflect the real visual acuity duo to the exaggeration or disguise of the wounded. We suggest to use "the best corrected presenting distance visual acuity" instead of "presenting distance visual acuity" in order to avoid the influences of the exaggeration or disguise of the wounded.

  10. Visual acuity evaluated by pattern-reversal visual-evoked potential is affected by check size/visual angle

    Institute of Scientific and Technical Information of China (English)

    Xiping Chen; Qianqian Li; Xiaoqin Liu; Li Yang; Wentao Xia; Luyang Tao

    2012-01-01

    Objective To systemically explore the range of visual angles that affect visual acuity,and to establish the relationship between the P 1 component (peak latency ~100 ms) of the pattern-reversal visual-evoked potential (PRVEP) and the visual acuity at particular visual angles.Methods Two hundred and ten volunteers were divided into seven groups,according to visual acuity as assessed by the standard logarithmic visual acuity chart (SLD-II).For each group,the PRVEP components were elicited in response to visual angle presentations at 8°,4°,2°,1 °/60′,30′,15′,and 7.5′,in the whiteblack chess-board reversal mode with a contrast level of 100% at a frequency of 2 Hz.Visual stimuli were presented monocularly,and 200 presentations were averaged for each block of trials.The early and stable component P1 was recorded at the mid-line of the occipital region (Oz) and analyzed with SPSS 13.00.Results (1) Oz had the maximum P1 amplitude;there was no significant difference between genders or for interocular comparison in normal controls and subjects with optic myopia.(2) The P1 latency decreased slowly below 30′,then increased rapidly.The P1 amplitude initially increased with check size,and was maximal at ~1° and ~30′.(3) The P1 latency in the group with visual acuity ≤0.2 was significantly different at 8°,15′ and 7.5′,while the amplitude differed at all visual angles,compared with the group with normal vision.Diferences in P1 for the groups with 0.5 and 0.6 acuity were only present at visual angles <1°.(4) Regression analysis showed that the P 1 latency and amplitude were associated with visual acuity over the full range of visual angles.There was a moderate correlation at visual angles <30′.Regression equations were calculated for the P1 components and visual acuity,based on visual angle.Conclusion (1) Visual angle should be taken into consideration when exploring the function of the visual pathway,especially visual acuity.A visual angle

  11. Dynamic Visual Acuity Training in Cricket Players

    Directory of Open Access Journals (Sweden)

    Renee Edgar, B.Optom

    2015-04-01

    Full Text Available Background: Dynamic visual acuity (DVA is the ability of an observer to correctly identify details of a moving target and is considered to be important for tasks like driving. Dynamic Visual Acuity is better in athletes involved in sports such as basketball and baseball; however, no previous studies have considered the sport of cricket. We conducted a study to determine whether there was any difference in DVA between cricket and non-cricket players. Method: Dynamic visual acuity was measured by asking subjects to identify the orientation of the gap of a moving Landolt C target as a four-alternative forced-choice task. The Landolt C targets had confusion bars surrounding them. The participants in the study were tested twice with a break of seven weeks. In between the two measurements, participants underwent two training sessions (similar to the testing sessions, each three weeks apart. Results: The initial mean DVA for cricket players was 107.7 deg/sec, and the mean DVA for non-cricket players was 105.5 deg/sec, with a target size of 6/15. The subjects who participated in training (cricketers and non-cricketers improved in DVA by 41 deg/sec in contrast to the improvement in the non-training subjects of 18 deg/sec (p=0.0032. The cricketers who participated in the training improved in DVA by 44 deg/sec, whereas the cricketers who did not participate in the training improved by 19 deg/sec (p=0.0167. Conclusions: We found no significant difference in initial DVA between the cricket players and the non-cricket players. The training resulted in an extremely significant improvement in DVA performance by both the cricketers and non-cricketers.

  12. Visual acuity estimation from simulated images

    Science.gov (United States)

    Duncan, William J.

    Simulated images can provide insight into the performance of optical systems, especially those with complicated features. Many modern solutions for presbyopia and cataracts feature sophisticated power geometries or diffractive elements. Some intraocular lenses (IOLs) arrive at multifocality through the use of a diffractive surface and multifocal contact lenses have a radially varying power profile. These type of elements induce simultaneous vision as well as affecting vision much differently than a monofocal ophthalmic appliance. With myriad multifocal ophthalmics available on the market it is difficult to compare or assess performance in ways that effect wearers of such appliances. Here we present software and algorithmic metrics that can be used to qualitatively and quantitatively compare ophthalmic element performance, with specific examples of bifocal intraocular lenses (IOLs) and multifocal contact lenses. We anticipate this study, methods, and results to serve as a starting point for more complex models of vision and visual acuity in a setting where modeling is advantageous. Generating simulated images of real- scene scenarios is useful for patients in assessing vision quality with a certain appliance. Visual acuity estimation can serve as an important tool for manufacturing and design of ophthalmic appliances.

  13. Bayesian model of Snellen visual acuity

    Science.gov (United States)

    Nestares, Oscar; Navarro, Rafael; Antona, Beatriz

    2003-07-01

    A Bayesian model of Snellen visual acuity (VA) has been developed that, as far as we know, is the first one that includes the three main stages of VA: (1) optical degradations, (2) neural image representation and contrast thresholding, and (3) character recognition. The retinal image of a Snellen test chart is obtained from experimental wave-aberration data. Then a subband image decomposition with a set of visual channels tuned to different spatial frequencies and orientations is applied to the retinal image, as in standard computational models of early cortical image representation. A neural threshold is applied to the contrast responses to include the effect of the neural contrast sensitivity. The resulting image representation is the base of a Bayesian pattern-recognition method robust to the presence of optical aberrations. The model is applied to images containing sets of letter optotypes at different scales, and the number of correct answers is obtained at each scale; the final output is the decimal Snellen VA. The model has no free parameters to adjust. The main input data are the eyes optical aberrations, and standard values are used for all other parameters, including the StilesCrawford effect, visual channels, and neural contrast threshold, when no subject specific values are available. When aberrations are large, Snellen VA involving pattern recognition differs from grating acuity, which is based on a simpler detection (or orientation-discrimination) task and hence is basically unaffected by phase distortions introduced by the optical transfer function. A preliminary test of the model in one subject produced close agreement between actual measurements and predicted VA values. Two examples are also included: (1) application of the method to the prediction of the VA in refractive-surgery patients and (2) simulation of the VA attainable by correcting ocular aberrations. 2003 Optical Society of America

  14. Potential acuity meter for predicting visual acuity after Nd:YAG posterior capsulotomy

    Energy Technology Data Exchange (ETDEWEB)

    Smiddy, W.E.; Radulovic, D.; Yeo, J.H.; Stark, W.J.; Maumenee, A.E.

    1986-03-01

    We studied 30 patients with opacifications of the posterior capsule to determine if the potential acuity meter (PAM) could accurately predict final visual outcome after Nd:YAG discussion. The final visual acuity was within one line of the PAM prediction in 22 of 30 patients (73%), better by two or more lines in seven patients (23%), and worse in one patient (4%) by two lines. Although in thicker capsules the final acuity was occasionally better than the PAM prediction, the rates of false negative and false positive predictions were very low. Mild cystoid macular edema (3 patients), age-related macular degeneration (3 patients), intraocular lens status, and level of initial acuity did not diminish PAM accuracy. The PAM effectively predicts final visual acuity after YAG posterior capsulotomy, when used in a patient, unhurried manner.

  15. An Association between Poor Eyesight and Work Efficiency: Far Visual Acuity and Near Visual Acuity and Work Efficiency

    OpenAIRE

    高橋, ひとみ; 北村, 佳子; 衞藤, 隆

    2012-01-01

    While the number of people engaging in VDT work increases, "The summary of new VDT work guidelines" was announced (H 12.4) by the Ministry of Health, Labor and Welfare , and far visual acuity test and near visual acuity test are now obligatory. Early detection and early treatment of poor eyesight can increase efficiency and can promote work in a comfortable state. On October 31, 2011, we carried out tests for visual acuity and near visual acuity (using an NV-300 automatic eyesight measuring d...

  16. Novel method for analyzing snellen visual acuity measurements.

    Science.gov (United States)

    Gregori, Ninel Z; Feuer, William; Rosenfeld, Philip J

    2010-01-01

    Most retrospective reviews convert Snellen visual acuity measurements obtained during routine clinic visits to logarithm of the minimum angle of resolution (logMAR) units so that statistical manipulations can be performed. However, visual acuity measurements expressed as logMAR units are not intuitively interpretable by clinicians. A more intuitive approach is presented here which uses the conversion of Snellen visual acuity fractions to Early Treatment Diabetic Retinopathy Study (ETDRS) letter scores for statistical manipulations. Snellen visual acuity measurements were converted to approximate ETDRS (approxETDRS) letter scores for statistical manipulations and then converted back to Snellen equivalent fractions. The formula to convert Snellen visual acuity measurements to approxETDRS letter scores is 85 + 50 x log (Snellen fraction), which may be rounded to the nearest letter. A linear relationship exists between true ETDRS letter scores, approxETDRS letter scores, and logMAR units. The interconversion between Snellen visual acuity measurements, logMAR units, and approxETDRS letter scores was prepared in a tabular form for easy reference. The same outcomes (in Snellen fractions) were obtained with statistical manipulation of either approxETDRS letter scores or logMAR conversions. Conversion of Snellen visual acuity fractions to approxETDRS letter scores for the purpose of performing statistical manipulations provides more readily interpretable outcomes compared with the current strategy of converting Snellen visual acuity fractions to logMAR units.

  17. Psychophysics of prosthetic vision: I. Visual scanning and visual acuity.

    Science.gov (United States)

    Chen, S C; Hallum, L E; Suaning, G J; Lovell, N H

    2006-01-01

    Recipients of vision prosthesis prototypes have reported electrically elicited visual perceptions as discrete dots of light (phosphenes). Phosphenes construct the scenery in discontinuous small isolated patches, resulting in visual information deficit to a large portion of the visual field. Visual scanning therefore plays an important role in the utility of prosthetic vision. In a psychophysical study, normally sighted subjects undertook a visual acuity task in a simulation of prosthetic vision with scanning facilitated by head movements. Subjects who adopted the circular scanning technique (4/12) correctly identified >60% of the test items, compared to subjects with no particular scanning patterns (3/12) with <50%. Increased head movement velocity was correlated to increased performance; at optimal scanning velocities, we estimated a 50% increase in identification rate or a two-fold improvement in visual acuity threshold compared to otherwise complete lack of scanning movement. Improved performance likely resulted from positive interactions with the temporal processes of the human visual system, which may as much as double the spatial information of that originally afforded by the phosphene lattice.

  18. Visual acuity and X-linked color blindness.

    Science.gov (United States)

    Jägle, Herbert; de Luca, Emanuela; Serey, Ludwig; Bach, Michael; Sharpe, Lindsay T

    2006-04-01

    Optimal sampling for visual acuity requires a fine array of cones with identical sensitivity. Thus, dichromats, whose inner fovea is made up of cones having the same spectral sensitivity, may have better than normal visual acuity. We investigated this by comparing the visual acuities of trichromats and X-linked dichromats, while taking into account the different molecular genetics underlying the disorder. Our subjects were age- and refraction-matched groups of normals (n=8) and X-linked dichromats (n=13). The dichromats (four protanopes and nine deuteranopes) were genotyped and classified according to whether they carried a single (n=6) or multiple (n=7) visual pigment genes on their X-chromosome. Visual acuity was measured in both eyes with the Freiburger Visual Acuity Test. Normal trichromats and ungenotyped dichromats do not significantly differ in visual acuity, nor do ungenotyped protanopes and deuteranopes. However, multi-gene dichromats, who possess more than one photopigment gene in the array, all of which encode for the same long- or middle-wavelength sensitive photopigment, have significantly higher visual acuity than either normal trichromats or dichromats who have only a single-gene. Multi-gene dichromats may benefit from a reduction in chromatic aberration and chromatic noise in the high acuity channel, normally a consequence of combining signals from different cone photoreceptor types and of cone-specific patterns of retinal image defocus and blur. Single-gene dichromats may not share in the advantage because of other molecular differences that influence the development of the retinal mosaic and/or its visual pathways.

  19. To Further the Near-vision Visual Acuity Test (1) : The Necessity of Near-vision Visual Acuity Testing from the Purpose of the Visual Acuity Tests of the School(Special Issue Dedicated to Professor TAKENAKA Teruo)

    OpenAIRE

    高橋, ひとみ; 川端, 秀仁; 衛藤, 隆

    2014-01-01

    Children are given visual acuity tests at school. The purpose of the tests is to facilitate school education. There are two types of visual acuity: far- and near-vision visual acuity. Far-vision visual acuity is required, for example, when reading something written on a whiteboard in a classroom. On the other hand, near-vision visual acuity is needed when reading textbooks, notebooks, or when looking at computer screens. However, only far-vision visual acuity tests are typically included in m...

  20. Visual acuity in mammals: effects of eye size and ecology.

    Science.gov (United States)

    Veilleux, Carrie C; Kirk, E Christopher

    2014-01-01

    Previous comparative research has attributed interspecific variation in eye size among mammals to selection related to visual acuity. Mammalian species have also been hypothesized to differ in visual acuity partly as a result of differences in ecology. While a number of prior studies have explored ecological and phylogenetic effects on eye shape, a broad comparative analysis of the relationships between visual acuity, eye size and ecology in mammals is currently lacking. Here we use phylogenetic comparative methods to explore these relationships in a taxonomically and ecologically diverse sample of 91 mammal species. These data confirm that axial eye length and visual acuity are significantly positively correlated in mammals. This relationship conforms to expectations based on theoretical optics and prior analyses of smaller comparative samples. Our data also demonstrate that higher visual acuity in mammals is associated with: (1) diurnality and (2) predatory habits once the effects of eye size and phylogeny have been statistically controlled. These results suggest that interspecific variation in mammalian visual acuity is the result of a complex interplay between phylogenetic history, visual anatomy and ecology.

  1. Changes in the clinical measurement of visual acuity

    Science.gov (United States)

    Bailey, I. L.; Jackson, A. J.

    2016-11-01

    In 1862, Hermann Snellen introduced his letter chart for the clinical measurement of visual acuity. His chart presented letters,or optotypes, arranged in a progressively diminishing size sequence, and the visual acuity was determined by the smallest letters that could read at a specified distance. Numerous modifications of the design of the optotypes, the progression of size and the chart layout were suggested, and in 1976, Bailey and Lovie published a set of design principles that made the visual task the same at all size levels, so that size become the only significant variable. This required the same number of letters at each size level, fixed spacing ratios and a logarithmic progression of size. This facilitates more precise quantification of visual acuity by giving credit for every letter read correctly, and this gives clinicians tighter confidence limits for determining changes or differences in visual acuity. However, optotype choices, and associated spacing arrangements can have significant effects on visual acuity scores as can viewing conditions and testing protocols. Computer based visual acuity tests are becoming more commonplace, there will be more variety in test charts and procedures which will create some problems for making comparisons between tests.

  2. Infant Visual Assessment: Using Eye Tracking to Measure Visual Acuity

    Directory of Open Access Journals (Sweden)

    Eliza Burton

    2012-05-01

    Full Text Available A technique commonly used to assess infants' visual acuity is forced-choice preferential looking, which relies on the propensity of infants to look at patterned stimuli over uniform grey. Existing tests use trained examiners to judge where an infant fixates; however, eye trackers offer the opportunity to measure eye movements quickly and automatically. In the present study infants' visual acuity was measured using a remote Tobii eye tracker (Tobii T120. Thirteen infants aged 4–8 months were seated before a screen and presented with a preferential looking task. On each trial a black and white chequerboard of variable spatial frequency was displayed on half of the screen, while uniform grey was displayed elsewhere. Eye tracking data were used to determine whether the infant fixated the chequerboard and to update the spatial frequency on subsequent trials according to a weighted up-down staircase targeting the 75% threshold. This initial study showed data in line with age norms are consistent across two testing sessions for some infants. Others yielded poor data or inconsistent performance. Future modifications will aim to make the test more engaging and to optimise its power and speed. These will provide a basis for a full assessment of the test's accuracy and reliability.

  3. Comparison of Applicability of Different Visual Acuity Charts for Pediatric Outpatient Visual Tests

    Institute of Scientific and Technical Information of China (English)

    Haili Fang; Hongxing Diao; Linxing Chen; Junwen Zeng

    2014-01-01

    Purpose: To evaluate the applicability of different visual acu-ity charts for outpatient pediatric visual tests. Methods: Fifty-three children (53 eyes) aged 4-8 years un-dergoing visual acuity tests as outpatients were randomly se-lected for this study. The best corrected visual acuity (BCVA) of the eye with better visual acuity was measured for each child using the digital LogMAR visual chart,.the ETDRS vi-sual chart,.and a new standard logarithm visual chart;.all measurements were repeated twice and the BCVA was record-ed. Paired comparisons were made between the LogMAR vi-sual acuity chart and ETDRS chart measurements or between the ETDRS chart and logarithm visual acuity chart measure-ments for statistical analysis of the differences in measurement of visual acuity..The results of different measurements by the same chart were compared to evaluate the consistency of the measurement results..Bland-Altman analysis was employed to evaluate the most suitable chart for outpatient measurement of visual acuity in children. Results:.Bland-Altman analysis revealed that the mean visual acuity measured was. (0.447 ±0.017 LogMAR).by the digital LogMAR chart,.(0.301±0.024 LogMAR).by the standard log-arithm visual acuity chart, and (0.309 ±0.018 LogMAR) by the ETDRS visual acuity chart. The BCVA was significantly lower when measured by the LogMAR visual acuity chart than by the ETDRS chart (P0.05)..The Bland-Altman plot showed that the high-est consistency was obtained with the digital LogMAR chart, with a difference between two repeated measurements of 0.068 LogMAR,.compared to 0.090 and 0.072 LogMAR for the logarithm and ETDRS visual acuity charts, respectively. Conclusion: All three types of visual acuity charts are appli-cable for outpatient measurement of pediatric visual acuity. The ETDRS and logarithm visual acuity charts have a higher consistency, but the LogMAR visual acuity chart shows better reproducibility..Consequently,.it is difficult to identify and

  4. Photometric Compliance of Tablet Screens and Retro-Illuminated Acuity Charts As Visual Acuity Measurement Devices.

    Directory of Open Access Journals (Sweden)

    I A T Livingstone

    Full Text Available Mobile technology is increasingly used to measure visual acuity. Standards for chart-based acuity tests specify photometric requirements for luminance, optotype contrast and luminance uniformity. Manufacturers provide some photometric data but little is known about tablet performance for visual acuity testing. This study photometrically characterised seven tablet computers (iPad, Apple inc. and three ETDRS (Early Treatment Diabetic Retinopathy Study visual acuity charts with room lights on and off, and compared findings with visual acuity measurement standards. Tablet screen luminance and contrast were measured using nine points across a black and white checkerboard test screen at five arbitrary brightness levels. ETDRS optotypes and adjacent white background luminance and contrast were measured. All seven tablets (room lights off exceeded the most stringent requirement for mean luminance (≥ 120 cd/m2 providing the nominal brightness setting was above 50%. All exceeded contrast requirement (Weber ≥ 90% regardless of brightness setting, and five were marginally below the required luminance uniformity threshold (Lmin/Lmax ≥ 80%. Re-assessing three tablets with room lights on made little difference to mean luminance or contrast, and improved luminance uniformity to exceed the threshold. The three EDTRS charts (room lights off had adequate mean luminance (≥ 120 cd/m2 and Weber contrast (≥ 90%, but all three charts failed to meet the luminance uniformity standard (Lmin/Lmax ≥ 80%. Two charts were operating beyond manufacturer's recommended lamp replacement schedule. With room lights on, chart mean luminance and Weber contrast increased, but two charts still had inadequate luminance uniformity. Tablet computers showed less inter-device variability, higher contrast, and better luminance uniformity than charts in both lights-on and lights-off environments, providing brightness setting was >50%. Overall, iPad tablets matched or marginally out

  5. Comparing Visual Acuity Measured by Lea Symbols and Patti Pics.

    Science.gov (United States)

    Singman, Eric L; Matta, Noelle S; Tian, Jing; Silbert, David I

    2015-01-01

    There is little data validating most illiterate eye charts. Lea Symbols®, however, have been well validated in numerous studies. In this study, we compare the assessment of visual acuity employing both the Lea Symbol hanging wall Early Treatment Diabetic Retinopathy Study (ETDRS)-style chart and a similar Patti Pics® ETDRS-style chart in order to determine whether the two charts provide clinically similar data. We tested the vision of the right eyes of fifty-two consecutive patients. Patients were cooperative children or adults between the ages of 3 and 88 years (mean 58 years). We alternated the order of the chart used first. Patients were also categorized by age and by visual acuity. The visual acuities measured by the two charts were equal for 83% of the measurements (forty-three eyes). In 8% of eyes (four eyes), the visual acuity measured with the Lea Symbols was one line better than that measured by the Patti Pics; in 9% of eyes (five eyes), the acuity from the Patti Pics chart measured one line better than the Lea Symbols. There was no difference in measurements for either adults or children or among patients with different visual acuities. We believe this study will serve to provide useful information when choosing an eye chart to assess visual acuity in a clinic setting. Patti Pics performed similarly to Lea Symbols in adults and children tested in a multi-specialty ophthalmology practice. We suspect that it would also perform similarly in the primary care and school settings. © 2015 Board of regents of the University of Wisconsin System, American Orthoptic Journal, Volume 65, 2015, ISSN 0065-955X, E-ISSN 1553-4448.

  6. The Effect of Zeaxanthin on the Visual Acuity of Zebrafish.

    Directory of Open Access Journals (Sweden)

    Eric A Saidi

    Full Text Available Oral supplementation of carotenoids such as zeaxanthin or lutein which naturally occur in human retina have been shown to improve vision and prevent progression of damage to advanced AMD in some studies. The zebrafish eye shares many physiological similarities with the human eye and is increasingly being used as model for vision research. We hypothesized that injection of zeaxanthin into the zebrafish eye would improve the visual acuity of the zebrafish over time. Visual acuity, calculated in cycles per degree, was measured in adult zebrafish to establish a consistent baseline using the optokinetic response. Zeaxanthin dissolved into phosphate buffered saline (PBS or PBS only was injected into the anterior chamber of the right and left eyes of the Zebrafish. Visual acuities were measured at 1 week and 3, 8 and 12 weeks post-injection to compare to baseline values. Repeated measures ANOVA was used to compare visual acuities between fish injected with PBS and zeaxanthin. A significant improvement in visual acuity, 14% better than before the injection (baseline levels, was observed one week after injection with zeaxanthin (p = 0.04. This improvement peaked at more than 30% for some fish a few weeks after the injection and improvement in vision persisted at 3 weeks after injection (p = 0.006. The enhanced visual function was not significantly better than baseline at 8 weeks (p = 0.19 and returned to baseline levels 12 weeks after the initial injection (p = 0.50. Zeaxanthin can improve visual acuity in zebrafish eyes. Further studies are required to develop a better understanding of the role zeaxanthin and other carotenoids play during normal visual function.

  7. The Effect of Zeaxanthin on the Visual Acuity of Zebrafish.

    Science.gov (United States)

    Saidi, Eric A; Davey, Pinakin Gunvant; Cameron, D Joshua

    2015-01-01

    Oral supplementation of carotenoids such as zeaxanthin or lutein which naturally occur in human retina have been shown to improve vision and prevent progression of damage to advanced AMD in some studies. The zebrafish eye shares many physiological similarities with the human eye and is increasingly being used as model for vision research. We hypothesized that injection of zeaxanthin into the zebrafish eye would improve the visual acuity of the zebrafish over time. Visual acuity, calculated in cycles per degree, was measured in adult zebrafish to establish a consistent baseline using the optokinetic response. Zeaxanthin dissolved into phosphate buffered saline (PBS) or PBS only was injected into the anterior chamber of the right and left eyes of the Zebrafish. Visual acuities were measured at 1 week and 3, 8 and 12 weeks post-injection to compare to baseline values. Repeated measures ANOVA was used to compare visual acuities between fish injected with PBS and zeaxanthin. A significant improvement in visual acuity, 14% better than before the injection (baseline levels), was observed one week after injection with zeaxanthin (p = 0.04). This improvement peaked at more than 30% for some fish a few weeks after the injection and improvement in vision persisted at 3 weeks after injection (p = 0.006). The enhanced visual function was not significantly better than baseline at 8 weeks (p = 0.19) and returned to baseline levels 12 weeks after the initial injection (p = 0.50). Zeaxanthin can improve visual acuity in zebrafish eyes. Further studies are required to develop a better understanding of the role zeaxanthin and other carotenoids play during normal visual function.

  8. A case-control study of visual acuity in onychocryptosis.

    LENUS (Irish Health Repository)

    Hogan, Aisling M

    2012-02-01

    BACKGROUND: There are many theories surrounding the etiology of ingrown toenails (IGTN). Few factors have been formally assessed, but it is widely accepted that a poor nail cutting technique has a causative role. AIM: To investigate the hypothesis that decreased visual acuity may lead to inadequate nail cutting and the formation of IGTN. METHODS: A prospective case-control study was performed. Near and distance visual acuity were tested on a population with IGTN (n = 19) and compared with that of an age- and sex-matched control cohort (n = 24) who underwent epidermal cyst excision in the same tertiary referral center. Comparisons of visual acuity were made between groups by Mann-Whitney U-test. Differences were taken to be significant if P < 0.05. Institutional Review Board approval was sought and granted. RESULTS: No significant difference in visual acuity (near or distance) was demonstrated between patients with IGTN and the control group (P = 0.33). CONCLUSION: Visual acuity does not appear to play a significant role in the development of IGTN.

  9. Screening for significant refractive error using a combination of distance visual acuity and near visual acuity.

    Directory of Open Access Journals (Sweden)

    Peiyao Jin

    Full Text Available To explore the effectiveness of using a series of tests combining near visual acuity (NVA and distance visual acuity (DVA for large-scale screenings for significant refractive error (SRE in primary school children.Each participant underwent DVA, NVA and cycloplegic autorefraction measurements. SREs, including high myopia, high hyperopia and high astigmatism were analyzed. Cycloplegic refraction results were considered to be the gold standard for the comparison of different screening measurements. Receiver-operating characteristic (ROC curves were constructed to compare the area under the curve (AUC and the Youden index among DVA, NVA and the series combined tests of DVA and NVA. The efficacies (including sensitivity, specificity, positive predictive value, and negative predictive value of each test were evaluated. Only the right eye data of each participant were analysed for statistical purpose.A total of 4416 children aged 6 to 12 years completed the study, among which 486 students had right eye SRE (SRE prevalence rate = 11.01%. There was no difference in the prevalence of high hyperopia and high astigmatism among different age groups. However, the prevalence of high myopia significantly increased with the age (χ² = 381.81, p<0.01. High hyperopia was the biggest SRE factor associated with amblyopia(p<0.01,OR = 167.40, 95% CI: 75.14∼372.94. The DVA test was better than the NVA test for detecting high myopia (Z = 2.71, p<0.01, but the NVA test was better for detecting high hyperopia (Z = 2.35, p = 0.02 and high astigmatism (Z = 4.45, p<0.01. The series combined DVA and NVA test had the biggest AUC and the highest Youden Index for detecting high hyperopia, myopia, astigmatism, as well as all of the SREs (all p<0.01.The series combined DVA and NVA test was more accurate for detecting SREs than either of the two tests alone. This new method could be applied to large-scale SRE screening of children, aged 6 to 12, in areas that are less

  10. Visual acuity in larval zebrafish: behavior and histology

    Directory of Open Access Journals (Sweden)

    Mueller Kaspar P

    2010-03-01

    Full Text Available Abstract Background Visual acuity, the ability of the visual system to distinguish two separate objects at a given angular distance, is influenced by the optical and neuronal properties of the visual system. Although many factors may contribute, the ultimate limit is photoreceptor spacing. In general, at least one unstimulated photoreceptor flanked by two stimulated ones is needed to perceive two objects as separate. This critical interval is also referred to as the Nyquist frequency and is according to the Shannon sampling theorem the highest spatial frequency where a pattern can be faithfully transmitted. We measured visual acuity in a behavioral experiment and compared the data to the physical limit given by photoreceptor spacing in zebrafish larvae. Results We determined visual acuity by using the optokinetic response (OKR, reflexive eye movements in response to whole field movements of the visual scene. By altering the spatial frequency we determined the visual acuity at approximately 0.16 cycles/degree (cpd (minimum separable angle = 3.1°. On histological sections we measured the retinal magnification factor and the distance between double cones, that are thought to mediate motion perception. These measurements set the physical limit at 0.24 cpd (2.1°. Conclusion The maximal spatial information as limited by photoreceptor spacing can not be fully utilized in a motion dependent visual behavior, arguing that the larval zebrafish visual system has not matured enough to optimally translate visual information into behavior. Nevertheless behavioral acuity is remarkable close to its maximal value, given the immature state of young zebrafish larvae.

  11. Binocularity in the little owl, Athene noctua. II. Properties of visually evoked potentials from the Wulst in response to monocular and binocular stimulation with sine wave gratings.

    Science.gov (United States)

    Porciatti, V; Fontanesi, G; Raffaelli, A; Bagnoli, P

    1990-01-01

    Visually evoked potentials (VEPs) have been recorded from the Wulst surface of the little owl, Athene noctua, in response to counterphase-reversal of sinusoidal gratings with different contrast, spatial frequency and mean luminance, presented either monocularly or binocularly. Monocular full-field stimuli presented to either eye evoked VEPs of similar amplitude, waveform and latency. Under binocular viewing, VEPs approximately doubled in amplitude without waveform changes. VEPs with similar characteristics could be obtained in response to stimulation of the contralateral, but not ipsilateral, hemifield. These results suggest that a 50% recrossing occurs in thalamic efferents and that different ipsilateral and contralateral regions converge onto the same Wulst sites. The VEP amplitude progressively decreased with increase of the spatial frequency beyond 2 cycles/degree, and the high spatial frequency cut-off (VEP acuity) was under binocular viewing (8 cycles/degree) higher than under monocular (5 cycles/degree) viewing (200 cd/m2, 45% contrast). The VEP acuity increased with increase in the contrast and decreased with reduction of the mean luminance. The binocular gain in both VEP amplitude and VEP acuity was largest at the lowest luminance levels. Binocular VEP summation occurred in the medium-high contrast range. With decreased contrast, both monocular and binocular VEPs progressively decreased in amplitude and tended to the same contrast threshold. The VEP contrast threshold depended on the spatial frequency (0.6-1.8% in the range 0.12-2 cycles/degree). Binocular VEPs often showed facilitatory interaction (binocular/monocular amplitude ratio greater than 2), but the binocular VEP amplitude did not change either by changing the stimulus orientation (horizontal vs. vertical gratings) or by inducing different retinal disparities.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Alcohol and marijuana effects on static visual acuity.

    Science.gov (United States)

    Adams, A J; Brown, B; Flom, M C; Jones, R T; Jampolsky, A

    1975-11-01

    Static visual acuity was measured at two contrast levels (12 and 49%) in ten subjects in a double blind experiment involving five drug conditions of alcohol and marijuana (0.5 ml and 1.0 ml/kg body weight of 95% ethanol, 8 and 15 mg delta-9-tetrahydrocannabinol (THC), and a placebo). We found no statistically significant change in static visual acuity for any of the dose levels at any of the measurement time up to six hours following drug ingestion; this is sharply contrasted with the marked decrements in acuity which were found in the same subjects under the same drug conditions when the targets were in motion and required corrdinated eye movements for their resolution.

  13. Patterns of non-embolic transient monocular visual field loss.

    Science.gov (United States)

    Petzold, Axel; Islam, Niaz; Plant, G T

    2013-07-01

    The aim of this study was to systematically describe the semiology of non-embolic transient monocular visual field loss (neTMVL). We conducted a retrospective case note analysis of patients from Moorfields Eye Hospital (1995-2007). The variables analysed were age, age of onset, gender, past medical history or family history of migraine, eye affected, onset, duration and offset, perception (pattern, positive and negative symptoms), associated headache and autonomic symptoms, attack frequency, and treatment response to nifedipine. We identified 77 patients (28 male and 49 female). Mean age of onset was 37 years (range 14-77 years). The neTMVL was limited to the right eye in 36 % to the left in 47 % and occurred independently in either eye in 5 % of cases. A past medical history of migraine was present in 12 % and a family history in 8 %. Headache followed neTMVL in 14 % and was associated with autonomic features in 3 %. The neTMB was perceived as grey in 35 %, white in 21 %, black in 16 % and as phosphenes in 9 %. Most frequently neTMVL was patchy 20 %. Recovery of vision frequently resembled attack onset in reverse. In 3 patients without associated headache the loss of vision was permanent. Treatment with nifedipine was initiated in 13 patients with an attack frequency of more than one per week and reduced the attack frequency in all. In conclusion, this large series of patients with neTMVL permits classification into five types of reversible visual field loss (grey, white, black, phosphenes, patchy). Treatment response to nifidipine suggests some attacks to be caused by vasospasm.

  14. Visual Acuity and Contrast Sensitivity with compressed motion video

    NARCIS (Netherlands)

    Bijl, P.; Vries, S.C. de

    2009-01-01

    Video of Visual Acuity (VA) and Contrast Sensitivity (CS) test charts in a complex background was recorded using a CCD camera mounted on a computer-controlled tripod and fed into real-time MPEG2 compression/decompression equipment. The test charts were based on the Triangle Orientation

  15. Comparison of visual acuity results in preschool children with lea symbols and bailey-lovie e chart

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    Nijil Sanker

    2013-01-01

    Full Text Available Purpose: To compare visual acuity with two visual acuity charts in preschool children. Materials and Methods: Visual acuity measurement with Lea symbols and Bailey-Lovie tumbling E chart was performed on children between 3 and 6 years of age. Visual acuity data from the two charts were analyzed with Bland-Altman plot to determine the limits of agreement. The Wilcoxon signed test was performed in children aged 3-4 years and in children aged 5-6 years separately to evaluate the influence of age. The inter-eye difference between the two charts were further analyzed with the paired t-test. A p value < 0.05 was considered statistically significant. Results: A total of 47 children were enrolled for the study. The average logarithm of the Minimum Angle of Resolution (LogMAR monocular visual acuity with Lea symbols (0.17 ± 0.13 was better than the Bailey-Lovie tumbling E chart (0.22 ± 0.14. The mean difference between Bailey-Lovie tumbling E chart and Lea symbol chart was 0.05 ± 0.12 in logMAR units. A second analysis eliminating outliers showed the same result but lower differences (n = 43, 0.05 ± 0.05 logMAR units. Visual acuity results between the two charts in children aged 3-4 years showed a significant difference (p = 0.000, but not for children aged 5-6 years (p = 0.059. Inter-eye differences between the two charts was not statistically significant (p = 0.77. Conclusion: Bailey-Lovie tumbling E chart is comparable to the Lea symbols chart in pre-school children. But preference should be given to Lea symbols for children aged 3-4 years as the symbols are more familiar than a directional test for this age group.

  16. Should we add visual acuity ratios to referral criteria for potential cerebral visual impairment?

    Science.gov (United States)

    van der Zee, Ymie J; Stiers, Peter; Evenhuis, Heleen M

    To determine whether the assessment of visual acuity ratios might improve the referral of children with (sub)normal visual acuity but at risk of cerebral visual impairment. In an exploratory study, we assessed visual acuity, crowding ratio and the ratios between grating acuity (Teller Acuity Cards-II) and optotype acuity (Cambridge Crowding Cards) in 60 typically developing school children (mean age 5y8m±1y1m), 21 children with ocular abnormalities only (5y7m±1y9m) and 26 children with (suspected) brain damage (5y7m±1y11m). Sensitivities and specificities were calculated for targets and controls from the perspective of different groups of diagnosticians: youth health care professionals (target: children with any visual abnormalities), ophthalmologists and low vision experts (target: children at risk of cerebral visual impairment). For youth health care professionals subnormal visual acuity had the best sensitivity (76%) and specificity (70%). For ophthalmologists and low vision experts the crowding ratio had the best sensitivity (67%) and specificity (79 and 86%). Youth health care professionals best continue applying subnormal visual acuity for screening, whereas ophthalmologists and low vision experts best add the crowding ratio to their routine diagnostics, to distinguish children at risk of visual impairment in the context of brain damage from children with ocular pathology only. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  17. A Case of Functional (Psychogenic Monocular Hemianopia Analyzed by Measurement of Hemifield Visual Evoked Potentials

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    Tsuyoshi Yoneda

    2013-12-01

    Full Text Available Purpose: Functional monocular hemianopia is an extremely rare condition, for which measurement of hemifield visual evoked potentials (VEPs has not been previously described. Methods: A 14-year-old boy with functional monocular hemianopia was followed up with Goldmann perimetry and measurement of hemifield and full-field VEPs. Results: The patient had a history of monocular temporal hemianopia of the right eye following headache, nausea and ague. There was no relative afferent pupillary defect, and a color perception test was normal. Goldmann perimetry revealed a vertical monocular temporal hemianopia of the right eye; the hemianopia on the right was also detected with a binocular visual field test. Computed tomography, magnetic resonance imaging (MRI and MR angiography of the brain including the optic chiasm as well as orbital MRI revealed no abnormalities. On the basis of these results, we diagnosed the patient's condition as functional monocular hemianopia. Pattern VEPs according to the International Society for Clinical Electrophysiology of Vision (ISCEV standard were within the normal range. The hemifield pattern VEPs for the right eye showed a symmetrical latency and amplitude for nasal and temporal hemifield stimulation. One month later, the visual field defect of the patient spontaneously disappeared. Conclusions: The latency and amplitude of hemifield VEPs for a patient with functional monocular hemianopia were normal. Measurement of hemifield VEPs may thus provide an objective tool for distinguishing functional hemianopia from hemifield loss caused by an organic lesion.

  18. Outcome of visual acuity after surgical removal of pituitary adenomas

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    Grković Desanka

    2013-01-01

    Full Text Available Introduction. Pituitary adenomas with suprasellar extension may produce anterior visual pathway compression, resulting in characteristic visual deficit. Surgical decompression of these structures prevents further visual deterioration and its postop­ erative recovery. Objective. The aim of this study was to investigate pre­ and postoperative visual acuity (VA in patients with pituitary ad­ enomas, and to detect the influence of prognostic factors, such as symptoms duration, degree of visual acuity reduction and tumor size in the assessment of the prognosis of postoperative visual function. Methods. We analyzed 40 consecutive patients who fulfilled three criteria: evidence of preoperative visual dysfunction, transsphenoidal or transfrontal tumor resection and hystologically verified pituitary adenoma. A visual examination was performed under standard conditions, pre and postoperatively (10 days, one month and six months after surgery. A paired t­test was used to assess the differences of pre­ and postoperative characteristics values, and the Chisquare test of independence in the assessment of the influence of prognostic factors. Results. Postoperative improvement of VA was seen in 84.61% patients (68% eyes. Eyes with preoperative mild and moderate degree of VA reduction showed improvement in 89.65% eyes in contrast to 22.60% eyes with preoperative severe reduction of VA, which was all statistically significant. Eyes in patients with tumor smaller than 20 mm had improvement of VA in 91.66% eyes, while eyes with tumor larger than 40 mm had improvement of VA in 61.11% eyes, which was statistically significant. When symptoms duration was below two years the improvement of VA was detected in 65.38% eyes as related to 50% eyes with symptoms duration exceeding two years, which was not statistically significant. Conclusion. Pituitary adenomas commonly cause visual impairment. Postoperatively the majority of patients show a distinct improvement of

  19. Evaluation of visual acuity with Gen 3 night vision goggles

    Science.gov (United States)

    Bradley, Arthur; Kaiser, Mary K.

    1994-01-01

    Using laboratory simulations, visual performance was measured at luminance and night vision imaging system (NVIS) radiance levels typically encountered in the natural nocturnal environment. Comparisons were made between visual performance with unaided vision and that observed with subjects using image intensification. An Amplified Night Vision Imaging System (ANVIS6) binocular image intensifier was used. Light levels available in the experiments (using video display technology and filters) were matched to those of reflecting objects illuminated by representative night-sky conditions (e.g., full moon, starlight). Results show that as expected, the precipitous decline in foveal acuity experienced with decreasing mesopic luminance levels is effectively shifted to much lower light levels by use of an image intensification system. The benefits of intensification are most pronounced foveally, but still observable at 20 deg eccentricity. Binocularity provides a small improvement in visual acuity under both intensified and unintensified conditions.

  20. Effects of Horizontal Acceleration on Human Visual Acuity and Stereopsis

    Directory of Open Access Journals (Sweden)

    Chi-Ting Horng

    2015-01-01

    Full Text Available The effect of horizontal acceleration on human visual acuity and stereopsis is demonstrated in this study. Twenty participants (mean age 22.6 years were enrolled in the experiment. Acceleration from two different directions was performed at the Taiwan High-Speed Rail Laboratory. Gx and Gy (< and >0.1 g were produced on an accelerating platform where the subjects stood. The visual acuity and stereopsis of the right eye were measured before and during the acceleration. Acceleration <0.1 g in the X- or Y-axis did not affect dynamic vision and stereopsis. Vision decreased (mean from 0.02 logMAR to 0.25 logMAR and stereopsis declined significantly (mean from 40 s to 60.2 s of arc when Gx > 0.1 g. Visual acuity worsened (mean from 0.02 logMAR to 0.19 logMAR and poor stereopsis was noted (mean from 40 s to 50.2 s of arc when Gy > 0.1 g. The effect of acceleration from the X-axis on the visual system was higher than that from the Y-axis. During acceleration, most subjects complained of ocular strain when reading. To our knowledge, this study is the first to report the exact levels of visual function loss during Gx and Gy.

  1. Eye size and visual acuity influence vestibular anatomy in mammals.

    Science.gov (United States)

    Kemp, Addison D; Christopher Kirk, E

    2014-04-01

    The semicircular canals of the inner ear detect head rotations and trigger compensatory movements that stabilize gaze and help maintain visual fixation. Mammals with large eyes and high visual acuity require precise gaze stabilization mechanisms because they experience diminished visual functionality at low thresholds of uncompensated motion. Because semicircular canal radius of curvature is a primary determinant of canal sensitivity, species with large canal radii are expected to be capable of more precise gaze stabilization than species with small canal radii. Here, we examine the relationship between mean semicircular canal radius of curvature, eye size, and visual acuity in a large sample of mammals. Our results demonstrate that eye size and visual acuity both explain a significant proportion of the variance in mean canal radius of curvature after statistically controlling for the effects of body mass and phylogeny. These findings suggest that variation in mean semicircular canal radius of curvature among mammals is partly the result of selection for improved gaze stabilization in species with large eyes and acute vision. Our results also provide a possible functional explanation for the small semicircular canal radii of fossorial mammals and plesiadapiforms. Copyright © 2014 Wiley Periodicals, Inc.

  2. Hypoxia impairs visual acuity in snapper (Pagrus auratus).

    Science.gov (United States)

    Robinson, Esme; Jerrett, Alistair; Black, Suzanne; Davison, William

    2013-07-01

    We investigated the effect of environmental hypoxia on vision in snapper (Pagrus auratus). Juvenile snapper inhabit estuarine environments where oxygen conditions fluctuate on a seasonal basis. Optomotor experiments demonstrated that visual acuity is impaired by environmental hypoxia, but not until levels approach the critical oxygen tension (P crit) of this species (around 25% air-saturated seawater). In 100, 80, and 60% air-saturated seawater, a positive optomotor response was present at a minimum separable angle (M SA) of 1°. In 40% air-saturated seawater, vision was partially impaired with positive responses at M SAs of 2° and above. However, in 25% air-saturated seawater, visual acuity was seriously impaired, with positive responses only present at M SAs of 6° and above. Snapper were found to possess a choroid rete, facilitating the maintenance of high ocular oxygen partial pressures (PO2) during normoxia and moderate hypoxia (PO2, between 269 and 290 mmHg). However, at 40 and 25% water oxygen saturation, ocular PO2 was reduced to below 175 mmHg, which is perhaps linked to impairment of visual acuity in these conditions. The ability to preserve visual function during moderate hypoxia is beneficial for the maintenance of a visual lifestyle in the fluctuating oxygen environments of estuaries.

  3. NEW DEFINITIONS OF KINETIC VISUAL ACUITY AND KINETIC VISUAL FIELD AND THEIR AGING EFFECTS

    Directory of Open Access Journals (Sweden)

    Jinglong WU

    2009-01-01

    However, traditional kinetic visual acuity and kinetic visual field measurements do not factor in the effects of individual differences in simple reaction times. This study identifies problems with the traditional method employed to define kinetic visual acuity and kinetic visual fields, and proposes new definitions of kinetic visual acuity and kinetic visual fields that measure simple reaction times and their aging effects. Simple reaction time tests reveal that simple reaction times of senior citizens are longer than those of younger people. The results of appraisal tests between traditional and new kinetic visual acuity definitions demonstrate the appropriateness of the new kinetic visual acuity definition. The study also takes a quantitative look at the aging effects of kinetic visual fields, measuring kinetic visual field characteristics of senior citizens while assessing space dependence, light dependence and index speed dependence of young people. The results obtained show that kinetic visual field ranges decrease with age, particularly in upward visual fields rather than downward visual fields in all target conditions. Visual field angle reductions in the temple sides of upward visual fields were of particular note.

  4. [Fidelity of the potential acuity meter in the postoperative visual acuity of cataract surgery].

    Science.gov (United States)

    Chiacchio, Brenda Biagio; Sato, Ricardo Mitsuo; Siqueira, Roberta Bianca Peres; Marques, Frederico França

    2008-01-01

    To evaluate the correlation between the preoperative visual acuity (VA) obtained by the potential acuity meter (PAM) and the postoperative VA in a patient submitted to cataract surgery, as well as its correlation with the dominant morphologic classification of the cataract. This is a prospective study performed at the Hospital Monumento Study Center. Sixty-three eyes of 45 patients submitted to phacoemulsification with intraocular lens implantation were enrolled in this study and 1 eye had been excluded. Besides the complete examination in the preoperative period, PAM was used and its results were compared with the VA at the third postoperative month and correlated with the dominant morphologic cataract classification. The result was called satisfactory when the variation was equal to or less than two lines at the Snellen chart. We transformed the AV into logMAR for comparison with the literature. The mean age was 45.3 years with a mean VA of 0.64 logMAR by the PAM. At the third postoperative month, the mean best corrected visual acuity (BCVA) was 0.09 logMAR. The PAM overestimated the BCVA in 8 eyes (13%), underestimated it in 41 eyes (66%) and in 13 eyes (21%) the BCVA were the same. The satisfactory results regarding nuclear cataract were reduced in cases of higher density (1+/4 with 75.5% e 4+/4 with 33.3%) and increased in the posterior subcapsular cataracts (85.7%). PAM revealed an underestimation or maintenance of the BCVA in most cases (87%). Its fidelity was inversely proportional in the nuclear cataracts (1+/4 with 75.5% e 4+/4 with 33.3%) and higher in the posterior subcapsular cataracts.

  5. Differential processing of binocular and monocular gloss cues in human visual cortex

    Science.gov (United States)

    Di Luca, Massimiliano; Ban, Hiroshi; Muryy, Alexander; Fleming, Roland W.

    2016-01-01

    The visual impression of an object's surface reflectance (“gloss”) relies on a range of visual cues, both monocular and binocular. Whereas previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here, we used human functional MRI (fMRI) to test for brain areas selectively involved in the processing of binocular cues. We manipulated stereoscopic information to create four conditions that differed in their disparity structure and in the impression of surface gloss that they evoked. We performed multivoxel pattern analysis to find areas whose fMRI responses allow classes of stimuli to be distinguished based on their depth structure vs. material appearance. We show that higher dorsal areas play a role in processing binocular gloss information, in addition to known ventral areas involved in material processing, with ventral area lateral occipital responding to both object shape and surface material properties. Moreover, we tested for similarities between the representation of gloss from binocular cues and monocular cues. Specifically, we tested for transfer in the decoding performance of an algorithm trained on glossy vs. matte objects defined by either binocular or by monocular cues. We found transfer effects from monocular to binocular cues in dorsal visual area V3B/kinetic occipital (KO), suggesting a shared representation of the two cues in this area. These results indicate the involvement of mid- to high-level visual circuitry in the estimation of surface material properties, with V3B/KO potentially playing a role in integrating monocular and binocular cues. PMID:26912596

  6. Differential processing of binocular and monocular gloss cues in human visual cortex.

    Science.gov (United States)

    Sun, Hua-Chun; Di Luca, Massimiliano; Ban, Hiroshi; Muryy, Alexander; Fleming, Roland W; Welchman, Andrew E

    2016-06-01

    The visual impression of an object's surface reflectance ("gloss") relies on a range of visual cues, both monocular and binocular. Whereas previous imaging work has identified processing within ventral visual areas as important for monocular cues, little is known about cortical areas involved in processing binocular cues. Here, we used human functional MRI (fMRI) to test for brain areas selectively involved in the processing of binocular cues. We manipulated stereoscopic information to create four conditions that differed in their disparity structure and in the impression of surface gloss that they evoked. We performed multivoxel pattern analysis to find areas whose fMRI responses allow classes of stimuli to be distinguished based on their depth structure vs. material appearance. We show that higher dorsal areas play a role in processing binocular gloss information, in addition to known ventral areas involved in material processing, with ventral area lateral occipital responding to both object shape and surface material properties. Moreover, we tested for similarities between the representation of gloss from binocular cues and monocular cues. Specifically, we tested for transfer in the decoding performance of an algorithm trained on glossy vs. matte objects defined by either binocular or by monocular cues. We found transfer effects from monocular to binocular cues in dorsal visual area V3B/kinetic occipital (KO), suggesting a shared representation of the two cues in this area. These results indicate the involvement of mid- to high-level visual circuitry in the estimation of surface material properties, with V3B/KO potentially playing a role in integrating monocular and binocular cues. Copyright © 2016 the American Physiological Society.

  7. Perceptual Learning in Children With Visual Impairment Improves Near Visual Acuity

    NARCIS (Netherlands)

    Huurneman, Bianca; Boonstra, F. Nienke; Cox, Ralf F. A.; van Rens, Ger; Cillessen, Antonius H. N.

    2013-01-01

    PURPOSE. This study investigated whether visual perceptual learning can improve near visual acuity and reduce foveal crowding effects in four-to nine-year-old children with visual impairment. METHODS. Participants were 45 children with visual impairment and 29 children with normal vision. Children w

  8. Perceptual learning in children with visual impairment improves near visual acuity

    NARCIS (Netherlands)

    Huurneman, B.; Boonstra, F.N.; Cox, R.F.; Rens, G. van; Cillessen, A.H.N.

    2013-01-01

    PURPOSE: This study investigated whether visual perceptual learning can improve near visual acuity and reduce foveal crowding effects in four- to nine-year-old children with visual impairment. METHODS: Participants were 45 children with visual impairment and 29 children with normal vision. Children

  9. Perceptual Learning in Children With Visual Impairment Improves Near Visual Acuity

    NARCIS (Netherlands)

    Huurneman, Bianca; Boonstra, F. Nienke; Cox, Ralf F. A.; van Rens, Ger; Cillessen, Antonius H. N.

    2013-01-01

    PURPOSE. This study investigated whether visual perceptual learning can improve near visual acuity and reduce foveal crowding effects in four-to nine-year-old children with visual impairment. METHODS. Participants were 45 children with visual impairment and 29 children with normal vision. Children w

  10. Enhanced monocular visual odometry integrated with laser distance meter for astronaut navigation.

    Science.gov (United States)

    Wu, Kai; Di, Kaichang; Sun, Xun; Wan, Wenhui; Liu, Zhaoqin

    2014-03-11

    Visual odometry provides astronauts with accurate knowledge of their position and orientation. Wearable astronaut navigation systems should be simple and compact. Therefore, monocular vision methods are preferred over stereo vision systems, commonly used in mobile robots. However, the projective nature of monocular visual odometry causes a scale ambiguity problem. In this paper, we focus on the integration of a monocular camera with a laser distance meter to solve this problem. The most remarkable advantage of the system is its ability to recover a global trajectory for monocular image sequences by incorporating direct distance measurements. First, we propose a robust and easy-to-use extrinsic calibration method between camera and laser distance meter. Second, we present a navigation scheme that fuses distance measurements with monocular sequences to correct the scale drift. In particular, we explain in detail how to match the projection of the invisible laser pointer on other frames. Our proposed integration architecture is examined using a live dataset collected in a simulated lunar surface environment. The experimental results demonstrate the feasibility and effectiveness of the proposed method.

  11. Changes in brain morphology in albinism reflect reduced visual acuity.

    Science.gov (United States)

    Bridge, Holly; von dem Hagen, Elisabeth A H; Davies, George; Chambers, Claire; Gouws, Andre; Hoffmann, Michael; Morland, Antony B

    2014-07-01

    Albinism, in humans and many animal species, has a major impact on the visual system, leading to reduced acuity, lack of binocular function and nystagmus. In addition to the lack of a foveal pit, there is a disruption to the routing of the nerve fibers crossing at the optic chiasm, resulting in excessive crossing of fibers to the contralateral hemisphere. However, very little is known about the effect of this misrouting on the structure of the post-chiasmatic visual pathway, and the occipital lobes in particular. Whole-brain analyses of cortical thickness in a large cohort of subjects with albinism showed an increase in cortical thickness, relative to control subjects, particularly in posterior V1, corresponding to the foveal representation. Furthermore, mean cortical thickness across entire V1 was significantly greater in these subjects compared to controls and negatively correlated with visual acuity in albinism. Additionally, the group with albinism showed decreased gyrification in the left ventral occipital lobe. While the increase in cortical thickness in V1, also found in congenitally blind subjects, has been interpreted to reflect a lack of pruning, the decreased gyrification in the ventral extrastriate cortex may reflect the reduced input to the foveal regions of the ventral visual stream. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Visual acuity and patient satisfaction at varied distances and lighting conditions after implantation of an aspheric diffractive multifocal one-piece intraocular lens

    Directory of Open Access Journals (Sweden)

    Chang DH

    2016-08-01

    Full Text Available Daniel H Chang Empire Eye and Laser Center, Bakersfield, CA, USA Purpose: The aim of the study is to evaluate the visual acuity and patient satisfaction at varied distances under photopic and mesopic lighting conditions in patients bilaterally implanted with aspheric diffractive multifocal one-piece intraocular lenses. Methods: In this retrospective–prospective study, 16 patients with a mean age of 66.2±9.2 years (range: 50–81 years who had undergone bilateral phacoemulsification surgery with implantation of a Tecnis multifocal one-piece intraocular lens (ZMB00 were evaluated. Monocular and binocular uncorrected and distance-corrected visual acuities were measured at distance (20 ft, intermediate (70–80 cm, and near (35–40 cm under photopic (85 cd/m2 and mesopic (3 cd/m2 lighting conditions and were compared using the paired t-test. All patients also completed a subjective questionnaire. Results: At a mean follow-up of 9.5±3.9 months, distance, near, and intermediate visual acuity improved significantly from preoperative acuity. Under photopic and mesopic conditions, 93.8% and 62.5% of patients, respectively, had binocular uncorrected intermediate visual acuity of 20/40 or better, and 62.5% and 31.3% of patients had binocular uncorrected near visual acuity of 20/20 or better. All patients were satisfied with their overall vision without using glasses and/or contact lenses when compared with before surgery. A total of 87.5% of patients reported no glare and 68.8% of patients reported no halos around lights at night. Conclusion: Tecnis multifocal one-piece intraocular lenses provide good distance, intermediate, and near visual acuity under photopic as well as mesopic lighting conditions. High levels of spectacle independence with low levels of photic phenomenon were achieved, resulting in excellent patient satisfaction. Keywords: Tecnis multifocal one-piece IOL, photopic visual acuity, mesopic visual acuity, intermediate visual

  13. Experimental validation of a Bayesian model of visual acuity.

    LENUS (Irish Health Repository)

    Dalimier, Eugénie

    2009-01-01

    Based on standard procedures used in optometry clinics, we compare measurements of visual acuity for 10 subjects (11 eyes tested) in the presence of natural ocular aberrations and different degrees of induced defocus, with the predictions given by a Bayesian model customized with aberrometric data of the eye. The absolute predictions of the model, without any adjustment, show good agreement with the experimental data, in terms of correlation and absolute error. The efficiency of the model is discussed in comparison with image quality metrics and other customized visual process models. An analysis of the importance and customization of each stage of the model is also given; it stresses the potential high predictive power from precise modeling of ocular and neural transfer functions.

  14. Is theta burst stimulation applied to visual cortex able to modulate peripheral visual acuity?

    Directory of Open Access Journals (Sweden)

    Sabrina Brückner

    Full Text Available Repetitive transcranial magnetic stimulation is usually applied to visual cortex to explore the effects on cortical excitability. Most researchers therefore concentrate on changes of phosphene threshold, rarely on consequences for visual performance. Thus, we investigated peripheral visual acuity in the four quadrants of the visual field using Landolt C optotypes before and after repetitive stimulation of the visual cortex. We applied continuous and intermittend theta burst stimulation with various stimulation intensities (60%, 80%, 100%, 120% of individual phosphene threshold as well as monophasic and biphasic 1 Hz stimulation, respectively. As an important result, no serious adverse effects were observed. In particular, no seizure was induced, even with theta burst stimulation applied with 120% of individual phosphene threshold. In only one case stimulation was ceased because the subject reported intolerable pain. Baseline visual acuity decreased over sessions, indicating a continuous training effect. Unexpectedly, none of the applied transcranial magnetic stimulation protocols had an effect on performance: no change in visual acuity was found in any of the four quadrants of the visual field. Binocular viewing as well as the use of peripheral instead of foveal presentation of the stimuli might have contributed to this result. Furthermore, intraindividual variability could have masked the TMS- induced effects on visual acuity.

  15. THE SIGNIFICANCE OF TESTING PREOPERATIVE VISUAL FUNCTION IN CATARACT USING LASER INTERFEROMETRIC VISUAL ACUITY AND ERG

    Institute of Scientific and Technical Information of China (English)

    1991-01-01

    Tests of preoperative visual function and prediction of postoperative E chart visual acuity(ECVA) using laser interferometric visual acuity(LIVA) and electroretinogram(ERG) were performed in 16 cases(19 eyes) of cataract. The results showed that the coincident rate between preoperative LIVA and postoperative ECVA was 63.2%, and there was a parallel correlation between preoperative amplitude of photopic ERG b-wave and postoperative ECVA in 79.0% of the eyes. Comparing these two methods, the test of LIVA ...

  16. Visual acuity in an opportunistic raptor, the chimango caracara (Milvago chimango).

    Science.gov (United States)

    Potier, Simon; Bonadonna, Francesco; Kelber, Almut; Duriez, Olivier

    2016-04-01

    Raptors are always considered to have an extraordinary resolving power of their eyes (high visual acuity). Nevertheless, raptors differ in their diet and foraging tactics, which could lead to large differences in visual acuity. The visual acuity of an opportunist bird of prey, the Chimango caracara (Mivalgo chimango) was estimated by operant conditioning. Three birds were trained to discriminate two stimuli, a positive grey uniform pattern and a negative grating pattern stimulus. The visual acuity range from 15.08 to 39.83 cycles/degrees. When compared to other birds, they have a higher visual acuity than non-raptorial birds, but they have the lowest visual acuity found in bird of prey so far. We discuss this result in the context of the ecology of the bird, with special focus on it is foraging tactic.

  17. Visual acuity and patient satisfaction at varied distances and lighting conditions after implantation of an aspheric diffractive multifocal one-piece intraocular lens

    Science.gov (United States)

    Chang, Daniel H

    2016-01-01

    Purpose The aim of the study is to evaluate the visual acuity and patient satisfaction at varied distances under photopic and mesopic lighting conditions in patients bilaterally implanted with aspheric diffractive multifocal one-piece intraocular lenses. Methods In this retrospective–prospective study, 16 patients with a mean age of 66.2±9.2 years (range: 50–81 years) who had undergone bilateral phacoemulsification surgery with implantation of a Tecnis multifocal one-piece intraocular lens (ZMB00) were evaluated. Monocular and binocular uncorrected and distance-corrected visual acuities were measured at distance (20 ft), intermediate (70–80 cm), and near (35–40 cm) under photopic (85 cd/m2) and mesopic (3 cd/m2) lighting conditions and were compared using the paired t-test. All patients also completed a subjective questionnaire. Results At a mean follow-up of 9.5±3.9 months, distance, near, and intermediate visual acuity improved significantly from preoperative acuity. Under photopic and mesopic conditions, 93.8% and 62.5% of patients, respectively, had binocular uncorrected intermediate visual acuity of 20/40 or better, and 62.5% and 31.3% of patients had binocular uncorrected near visual acuity of 20/20 or better. All patients were satisfied with their overall vision without using glasses and/or contact lenses when compared with before surgery. A total of 87.5% of patients reported no glare and 68.8% of patients reported no halos around lights at night. Conclusion Tecnis multifocal one-piece intraocular lenses provide good distance, intermediate, and near visual acuity under photopic as well as mesopic lighting conditions. High levels of spectacle independence with low levels of photic phenomenon were achieved, resulting in excellent patient satisfaction. PMID:27536061

  18. Monocular visual scene understanding: understanding multi-object traffic scenes.

    Science.gov (United States)

    Wojek, Christian; Walk, Stefan; Roth, Stefan; Schindler, Konrad; Schiele, Bernt

    2013-04-01

    Following recent advances in detection, context modeling, and tracking, scene understanding has been the focus of renewed interest in computer vision research. This paper presents a novel probabilistic 3D scene model that integrates state-of-the-art multiclass object detection, object tracking and scene labeling together with geometric 3D reasoning. Our model is able to represent complex object interactions such as inter-object occlusion, physical exclusion between objects, and geometric context. Inference in this model allows us to jointly recover the 3D scene context and perform 3D multi-object tracking from a mobile observer, for objects of multiple categories, using only monocular video as input. Contrary to many other approaches, our system performs explicit occlusion reasoning and is therefore capable of tracking objects that are partially occluded for extended periods of time, or objects that have never been observed to their full extent. In addition, we show that a joint scene tracklet model for the evidence collected over multiple frames substantially improves performance. The approach is evaluated for different types of challenging onboard sequences. We first show a substantial improvement to the state of the art in 3D multipeople tracking. Moreover, a similar performance gain is achieved for multiclass 3D tracking of cars and trucks on a challenging dataset.

  19. Sensitivity of The Dynamic Visual Acuity Test To Sensorimotor Change

    Science.gov (United States)

    Cohen, Helen; Bloomberg, Jacob; Elizalde, Elizabeth; Fregia, Melody

    1999-01-01

    Post-flight astronauts, acutely post-vestibular nerve section patients, and patients with severe chronic bilateral vestibular deficits have oscillopsia caused by reduced vestibulocular reflex gains and decreased postural stability. Therefore, as previous work has shown, a test of dynamic visual acuity (DVA), in which the subject must read numbers from a computer screen while standing still or walking in place provides a composite measure of sensorimotor integration. This measure may be useful for determining the level of recovery, post-flight, post-operatively, or after vestibular rehabilitation. To determine the sensitivity of DVA to change in impaired populations we have tested patients with acoustic neuromas before and during the first post-operative week after resection of the tumors, and with bilaterally labyrinthine deficient subjects before and after six weeks of balance rehabilitation therapy.

  20. ASTIGMATISM IN PRIMARY PTERYGIUM AND ITS EFFECT ON VISUAL ACUITY

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    Devika

    2015-09-01

    Full Text Available BACKGROUND: Pterygium is a fairly common condition in a tropical country like India with average incidence being 5.2%. Surgery being offered as a treatment for pterygium does not, at present, have a universally accepted indication based on the size. This study was done to make an attempt to define the indication for surgical exicision of pterygium. AIMS: To find out an association between increasing size of pterygium and degree of induced corneal astigmatism and to assess if corneal astigmatism induced by pterygium affects best corrected visual acuity (BCVA and thus making it an indication for pterygium excision surgery. SETTINGS AND DESIGN: Hospital Out Patient Departmen t (OPD based prospective clinical cross sectional study on patients with unilateral pterygium. METHODS AND MATERIAL : 33 patients were included in this study who had unilateral pterygium of varying sizes. Evaluation was done using slit - lamp beam for size o f pterygium in millimetre from the limbus, ketatometry using Bausch and Lomb keratometer, autorefractometer objective refraction readings, visual acuity and BCVA using Snellens chart. STATISTICAL ANALYSIS USED: Chi - square - test, Karl - Pearson correlation coe fficient, Kruskal - Wallis - co - efficient using SPSS statistics 22.0 . RESULTS: 33 people having unilateral pterygium were divided into three groups on the basis of size of the pterygium - ≤2mm, 2.1 - 3mm, >3mm. The co - relation coefficient between the astigmatism induced to BCVA was maximum for the 3rd group with pterygium size >3mm and was statistically significant. CONCLUSION: Pterygium induces ‘with the rule’ astigmatism. Surgery is indicated in patients of pterygium size >3mm as the astigmatism induced affects the BCVA

  1. A Case of Recurrent Transient Monocular Visual Loss after Receiving Sildenafil

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    Asaad Ghanem Ghanem

    2011-01-01

    Full Text Available A 53-year-old man was attended to the Clinic Ophthalmic Center, Mansoura University, Egypt, with recurrent transient monocular visual loss after receiving sildenafil citrate (Viagra for erectile dysfunction. Examination for possible risk factors revealed mild hypercholesterolemia. Family history showed that his father had suffered from bilateral nonarteritic anterior ischemic optic neuropathy (NAION. Physicians might look for arteriosclerotic risk factors and family history of NAION among predisposing risk factors before prescribing sildenafil erectile dysfunction drugs.

  2. Short-term monocular patching boosts the patched eye’s response in visual cortex

    Science.gov (United States)

    Zhou, Jiawei; Baker, Daniel H.; Simard, Mathieu; Saint-Amour, Dave; Hess, Robert F.

    2015-01-01

    Abstract Purpose: Several recent studies have demonstrated that following short-term monocular deprivation in normal adults, the patched eye, rather than the unpatched eye, becomes stronger in subsequent binocular viewing. However, little is known about the site and nature of the underlying processes. In this study, we examine the underlying mechanisms by measuring steady-state visual evoked potentials (SSVEPs) as an index of the neural contrast response in early visual areas. Methods: The experiment consisted of three consecutive stages: a pre-patching EEG recording (14 minutes), a monocular patching stage (2.5 hours) and a post-patching EEG recording (14 minutes; started immediately after the removal of the patch). During the patching stage, a diffuser (transmits light but not pattern) was placed in front of one randomly selected eye. During the EEG recording stage, contrast response functions for each eye were measured. Results: The neural responses from the patched eye increased after the removal of the patch, whilst the responses from the unpatched eye remained the same. Such phenomena occurred under both monocular and dichoptic viewing conditions. Conclusions: We interpret this eye dominance plasticity in adult human visual cortex as homeostatic intrinsic plasticity regulated by an increase of contrast-gain in the patched eye. PMID:26410580

  3. Perceptual learning in children with visual impairment improves near visual acuity.

    Science.gov (United States)

    Huurneman, Bianca; Boonstra, F Nienke; Cox, Ralf F A; van Rens, Ger; Cillessen, Antonius H N

    2013-09-17

    This study investigated whether visual perceptual learning can improve near visual acuity and reduce foveal crowding effects in four- to nine-year-old children with visual impairment. Participants were 45 children with visual impairment and 29 children with normal vision. Children with visual impairment were divided into three groups: a magnifier group (n = 12), a crowded perceptual learning group (n = 18), and an uncrowded perceptual learning group (n = 15). Children with normal vision also were divided in three groups, but were measured only at baseline. Dependent variables were single near visual acuity (NVA), crowded NVA, LH line 50% crowding NVA, number of trials, accuracy, performance time, amount of small errors, and amount of large errors. Children with visual impairment trained during six weeks, two times per week, for 30 minutes (12 training sessions). After training, children showed significant improvement of NVA in addition to specific improvements on the training task. The crowded perceptual learning group showed the largest acuity improvements (1.7 logMAR lines on the crowded chart, P visual impairment benefit from perceptual training. While task-specific improvements were observed in all training groups, transfer to crowded NVA was largest in the crowded perceptual learning group. To our knowledge, this is the first study to provide evidence for the improvement of NVA by perceptual learning in children with visual impairment. (http://www.trialregister.nl number, NTR2537.).

  4. Embolic and nonembolic transient monocular visual field loss: a clinicopathologic review.

    Science.gov (United States)

    Petzold, Axel; Islam, Niaz; Hu, Han-Hwa; Plant, Gordon T

    2013-01-01

    Transient monocular blindness and amaurosis fugax are umbrella terms describing a range of patterns of transient monocular visual field loss (TMVL). The incidence rises from ≈1.5/100,000 in the third decade of life to ≈32/100,000 in the seventh decade of life. We review the vascular supply of the retina that provides an anatomical basis for the types of TMVL and discuss the importance of collaterals between the external and internal carotid artery territories and related blood flow phenomena. Next, we address the semiology of TMVL, focusing on onset, pattern, trigger factors, duration, recovery, frequency-associated features such as headaches, and on tests that help with the important differential between embolic and non-embolic etiologies.

  5. Phacoemulsification cataract surgery in a large cohort of diabetes patients: visual acuity outcomes and prognostic factors

    DEFF Research Database (Denmark)

    Ostri, Christoffer; Lund-Andersen, Henrik; Sander, Birgit;

    2011-01-01

    To assess visual acuity outcomes after phacoemulsification cataract surgery in a large population of diabetic patients with all degrees of diabetic retinopathy.......To assess visual acuity outcomes after phacoemulsification cataract surgery in a large population of diabetic patients with all degrees of diabetic retinopathy....

  6. Comparison of Dynamic Visual Acuity between Water Polo Players and Sedentary Students

    Science.gov (United States)

    Quevedo-Junyent, Lluisa; Aznar-Casanova, Jose Antonio; Merindano-Encina, Dolores; Cardona, Genis; Sole-Forto, Joan

    2011-01-01

    In this study, we examined differences in dynamic visual acuity between elite and subelite water polo players and sedentary students. To measure dynamic visual acuity binocularly, we asked participants to indicate the orientation of a broken ring, similar to the Landolt C, which increased in size as it moved across a computer screen. Two different…

  7. Comparison of Dynamic Visual Acuity between Water Polo Players and Sedentary Students

    Science.gov (United States)

    Quevedo-Junyent, Lluisa; Aznar-Casanova, Jose Antonio; Merindano-Encina, Dolores; Cardona, Genis; Sole-Forto, Joan

    2011-01-01

    In this study, we examined differences in dynamic visual acuity between elite and subelite water polo players and sedentary students. To measure dynamic visual acuity binocularly, we asked participants to indicate the orientation of a broken ring, similar to the Landolt C, which increased in size as it moved across a computer screen. Two different…

  8. Initial findings on visual acuity thresholds in an African elephant (Loxodonta africana).

    Science.gov (United States)

    Shyan-Norwalt, Melissa R; Peterson, Jeff; Milankow King, Barbara; Staggs, Timothy E; Dale, Robert H I

    2010-01-01

    There are only a few published examinations of elephant visual acuity. All involved Asian elephants (Elephas maximus) and found visual acuity to be between 8' and 11' of arc for a stimulus near the tip of the trunk, equivalent to a 0.50 cm gap, at a distance of about 2 m from the eyes. We predicted that African elephants (Loxodonta africana) would have similarly high visual acuity, necessary to facilitate eye-trunk coordination for feeding, drinking and social interactions. When tested on a discrimination task using Landolt-C stimuli, one African elephant cow demonstrated a visual acuity of 48' of arc. This represents the ability to discriminate a gap as small as 2.75 cm in a stimulus 196 cm from the eye. This single-subject study provides a preliminary estimate of the visual acuity of African elephants.

  9. Visual acuity and quality of life in dry eye disease: Proceedings of the OCEAN group meeting.

    Science.gov (United States)

    Benítez-Del-Castillo, José; Labetoulle, Marc; Baudouin, Christophe; Rolando, Maurizio; Akova, Yonca A; Aragona, Pasquale; Geerling, Gerd; Merayo-Lloves, Jesús; Messmer, Elisabeth M; Boboridis, Kostas

    2017-04-01

    Dry eye disease (DED) results in tear film instability and hyperosmolarity, inflammation of the ocular surface and, ultimately, visual disturbance that can significantly impact a patient's quality of life. The effects on visual acuity result in difficulties with driving, reading and computer use and negatively impact psychological health. These effects also extend to the workplace, with a loss of productivity and quality of work causing substantial economic losses. The effects of DED and the impact on vision experienced by patients may not be given sufficient importance by ophthalmologists. Functional visual acuity (FVA) is a measure of visual acuity after sustained eye opening without blinking for at least 10 s and mimics the sustained visual acuity of daily life. Measuring dynamic FVA allows the detection of impaired visual function in patients with DED who may display normal conventional visual acuity. There are currently several tests and methods that can be used to measure dynamic visual function: the SSC-350 FVA measurement system, assessment of best-corrected visual acuity decay using the interblink visual acuity decay test, serial measurements of ocular and corneal higher order aberrations, and measurement of dynamic vision quality using the Optical Quality Analysis System. Although the equipment for these methods may be too large or unaffordable for use in clinical practice, FVA testing is an important assessment for DED.

  10. Visual acuity and pattern of visual field loss at presentation in pituitary adenoma.

    Science.gov (United States)

    Ogra, Siddharth; Nichols, Andrew D; Stylli, Stanley; Kaye, Andrew H; Savino, Peter J; Danesh-Meyer, Helen V

    2014-05-01

    Our purpose was to analyse the demographics, prevalence and pattern of visual field defects in patients with pituitary adenoma. We prospectively recruited 103 consecutive patients (206 eyes) presenting to a neurosurgical unit with pituitary adenoma. Ophthalmological examination and standard automated perimetry (Humphrey, 24-2 threshold) was performed. Severity of visual field defects was also assessed. The mean population age was 53.9 years (standard deviation=15). Visual loss was the most common reason for presentation (39%) followed by endocrine abnormality (21%) and headache (15%). Patients with endocrine abnormality on presentation were 10.9 years younger than those presenting with visual loss (p=0.001). Bitemporal defects were the most prevalent pattern (n=22, 41%) followed by homonymous defects (n=7, 13%). Of the patients with visual field loss, 33% had unilateral visual field defects. The mean visual acuity in those with bitemporal defects was 6/7.5 with half of these patients having 6/6 vision in both eyes. In conclusion, the majority of patients with pituitary adenoma have visual acuity better than 6/7.5 despite having visual field defects. While a bitemporal pattern of visual field loss is the most common, a significant proportion of patients had unilateral and altitudinal defects. Assessment of the visual field is essential to rule out chiasmal compression.

  11. More clinical observations on migraine associated with monocular visual symptoms in an Indian population

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    Vishal Jogi

    2016-01-01

    Full Text Available Context: Retinal migraine (RM is considered as one of the rare causes of transient monocular visual loss (TMVL and has not been studied in Indian population. Objectives: The study aims to analyze the clinical and investigational profile of patients with RM. Materials and Methods: This is an observational prospective analysis of 12 cases of TMVL fulfilling the International Classification of Headache Disorders-2nd edition (ICHD-II criteria of RM examined in Neurology and Ophthalmology Outpatient Department (OPD of Postgraduate Institute of Medical Education and Research (PGIMER, Chandigarh from July 2011 to October 2012. Results: Most patients presented in 3 rd and 4 th decade with equal sex distribution. Seventy-five percent had antecedent migraine without aura (MoA and 25% had migraine with Aura (MA. Headache was ipsilateral to visual symptoms in 67% and bilateral in 33%. TMVL preceded headache onset in 58% and occurred during headache episode in 42%. Visual symptoms were predominantly negative except in one patient who had positive followed by negative symptoms. Duration of visual symptoms was variable ranging from 30 s to 45 min. None of the patient had permanent monocular vision loss. Three patients had episodes of TMVL without headache in addition to the symptom constellation defining RM. Most of the tests done to rule out alternative causes were normal. Magnetic resonance imaging (MRI brain showed nonspecific white matter changes in one patient. Visual-evoked potential (VEP showed prolonged P100 latencies in two cases. Patent foramen ovale was detected in one patient. Conclusions: RM is a definite subtype of migraine and should remain in the ICHD classification. It should be kept as one of the differential diagnosis of transient monocular vision loss. We propose existence of "acephalgic RM" which may respond to migraine prophylaxis.

  12. Female carpet weavers' visual acuity and effective factors: Fordu rural area of Qom

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    Khajenasiri F.

    2007-11-01

    Full Text Available Background: Healthy vision of workers is one of the important elements in carpet weaving industry which has essential role in improving of the job quality and efficiency. Visual acuity is the primary outcome measure in most studies involving eye diseases. Ihe aim of this study was determination of visual acuity and its effective factors in women carpet weaver in fordu rural area of Qom has been investigated.  Methods: In a cross-sectional (descriptive-analytical study visual acuity of 177 women carpet weaver has been determined. Job hours per day, job history, age, literacy, trauma history, diabetes history, family history of eye diseases, eye diseases history and family size  of subjects were determined .Results: The results of study indicated that the right eyes visual acuity of 72.4 % of women were desirable (0 - 0.8 and 27.6 % were undesirable (0.9-1.2. These results for the left eyes were 69.5 % and 30.5 % respectively. In addition, the result showed that with increasing the job hours and history and age, percent of women with undesirable both eyes visual acuity were increased. With higher literacy levels, percent of women with undesirable both eyes visual acuity decreased. In subjects with truma history, the undesirable visual acuity was higher. In this study the relation between visual acuity and job history, age, literacy, truma history and eye diseases history were statistically significant (in all cases P<0.05.Conclusions: High percentage of women carpet weaver were in undesirable  visual acuity and in this study the relation between visual acuity and job history, age, literacy, trauma history and eye diseases history were statistically significant (in all cases P<0.05.

  13. Development of Pocket Vision Screener and its effectiveness at screening visual acuity deficits

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    Monica Raja

    2014-01-01

    Full Text Available Aim: The aim was to construct a visual acuity chart and find its effectiveness at screening visual acuity deficits. Materials and Methods: Two phases were involved in this study.Construction of the screener: Ten Sloan letters (C, D, H, K, N, O, R, S, V, and Z were selected and the letters were constructed and reduced to 0.2 logMAR acuity size (6.92 mm for viewing at 3 m. The screener contains three lines with seven letters in each. Few combinations of the seven letter sequences were chosen based on the row legibility scores. Three seven letter combinations close to the median of all combinations were selected, such that maximum difficulty score difference between the lines are <1%. Finding the effectiveness of the screener: 100 literate subjects with unaided visual acuity better than or equal to 6/60 were recruited for the study. Unaided visual acuity was tested using both the newly constructed Pocket Vision Screener and a logMAR visual acuity chart and the time taken to measure the visual acuity using both the charts was noted. Results: The mean age of the subjects was 43 ± 17 years. Subjects were classified as normal or deficient based on the logMAR visual acuity measurement. The screener was found to have 81% sensitivity, 94% specificity. The positive and negative predictive values were found to be 91% and 87%, respectively. A significant difference (P < 0.001 was found in the time taken to record visual acuity using both the charts. Conclusion: The Pocket Vision Screener can be used as a quick and accurate tool to screen subjects for visual acuity deficits, being highly sensitive, specific, and cost-effective.

  14. Effect of reduced visual acuity on precision of two-dimensional tracing movements.

    Science.gov (United States)

    Domkin, Dmitry; Richter, Hans O; Zetterlund, Christina; Lundqvist, Lars-Olov

    2016-01-01

    We intended to assess consequences of reduced visual acuity for performance in a natural simple motor task (tracing) using objective kinematic performance measures. Specifically, we intended to elucidate the kind of relationship between the task performance and best corrected binocular visual acuity and to determine the threshold of visual acuity when task performance starts to deteriorate. Ninety-five individuals with different best corrected visual acuity participated in the study (age 49±12 years, mean±SD, 27 men and 68 women). The participants manually traced maze-like visual patterns of different spatial complexity presented on the screen of a portable notebook computer using Clinical Kinematic Assessment Tool software. Tracing error was computed as performance measure in each trial with a spatial pattern matching technique - rigid point set registration method. The segmented linear regression analysis showed that the relation between visual acuity and tracing errors was best described with a regression function having a break point between two data segments. Tracing performance was unaffected by values of visual acuity below 0.2 on logMAR scale, but when logMAR values increased above this critical limit (i.e. when visual acuity is further reduced), tracing errors linearly increased. The rate of the increase of the tracing error correlated with the complexity of visual stimulus shape. Testing of fine motor functions with objective kinematic measures during visuomotor tasks may help differentiating between actual effects of reduced visual acuity on eye-hand coordination in individuals with similar levels of impairment of visual acuity. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  15. Development and clinical application of a color pediatric visual acuity chart

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    Shu-Guo Yin

    2014-12-01

    Full Text Available AIM: To introduce a new color pediatric visual acuity chart and its clinical application.METHODS:The color pediatric visual acuity chart was designed based on principle of visual angle. The optotype on the color chart had graphics. The progression rate of optotype size between 2 lines was 10(101/2 and 1.2589. A regular geometric progression of optotype sizes and distribution was employed to arrange 8 lines with 11 optotype on the color chart. The testing distance was 3m. The visual acuity score could be recorded as logarithm of the minimum angle of resolution notation or decimal notation. The reliability of naked distant measurements with this new chart was tested in one eye of 100 children(4 ~6 years oldtaking the Chinese national standard logarithm visual acuity chart standard. RESULTS: The color pediatric visual acuity chart and logarithmic chart controls, visual acuity test results that in the two groups had no significant difference(t=1.2671, P>0.05. Two sets of vision data existed positive correlation(r=0.924, PCONCLUSION:Children are easier to accept used new color pediatric visual acuity chart to inspect vision. New chart is reliability and apply to children's vision screening.

  16. The Eye Phone Study: reliability and accuracy of assessing Snellen visual acuity using smartphone technology.

    Science.gov (United States)

    Perera, C; Chakrabarti, R; Islam, F M A; Crowston, J

    2015-07-01

    Smartphone-based Snellen visual acuity charts has become popularized; however, their accuracy has not been established. This study aimed to evaluate the equivalence of a smartphone-based visual acuity chart with a standard 6-m Snellen visual acuity (6SVA) chart. First, a review of available Snellen chart applications on iPhone was performed to determine the most accurate application based on optotype size. Subsequently, a prospective comparative study was performed by measuring conventional 6SVA and then iPhone visual acuity using the 'Snellen' application on an Apple iPhone 4. Eleven applications were identified, with accuracy of optotype size ranging from 4.4-39.9%. Eighty-eight patients from general medical and surgical wards in a tertiary hospital took part in the second part of the study. The mean difference in logMAR visual acuity between the two charts was 0.02 logMAR (95% limit of agreement -0.332, 0.372 logMAR). The largest mean difference in logMAR acuity was noted in the subgroup of patients with 6SVA worse than 6/18 (n=5), who had a mean difference of two Snellen visual acuity lines between the charts (0.276 logMAR). We did not identify a Snellen visual acuity app at the time of study, which could predict a patients standard Snellen visual acuity within one line. There was considerable variability in the optotype accuracy of apps. Further validation is required for assessment of acuity in patients with severe vision impairment.

  17. Relationship between monocularly deprivation and amblyopia rats and visual system development

    Institute of Scientific and Technical Information of China (English)

    Yu Ma

    2014-01-01

    Objective:To explore the changes of lateral geniculate body and visual cortex in monocular strabismus and form deprived amblyopic rat, and visual development plastic stage and visual plasticity in adult rats.Methods:A total of60SD rats ages13 d were randomly divided intoA, B,C three groups with20 in each group, groupA was set as the normal control group without any processing, groupB was strabismus amblyopic group, using the unilateral extraocular rectus resection to establish the strabismus amblyopia model, groupC was monocular form deprivation amblyopia group using unilateral eyelid edge resection+ lid suture.At visual developmental early phase(P25), meta phase(P35), late phase(P45) and adult phase(P120), the lateral geniculate body and visual cortex area17 of five rats in each group were exacted forC-fosImmunocytochemistry. Neuron morphological changes in lateral geniculate body and visual cortex was observed, the positive neurons differences ofC-fos expression induced by light stimulation was measured in each group, and the condition of radiation development ofP120 amblyopic adult rats was observed.Results:In groupsB andC,C-fos positive cells were significantly lower thanthe control group atP25(P0.05),C-fos protein positive cells level of groupB was significantly lower than that of groupA(P<0.05).The binoculusC-fos protein positive cells level of groupsB andC were significantly higher than that of control group atP35,P45 andP120 with statistically significant differences(P<0.05).Conclusions:The increasing ofC-fos expression in geniculate body and visual cortex neurons of adult amblyopia suggests the visual cortex neurons exist a certain degree of visual plasticity.

  18. Visual Acuity Using Head-fixed Displays During Passive Self and Surround Motion

    Science.gov (United States)

    Wood, Scott J.; Black, F. Owen; Stallings, Valerie; Peters, Brian

    2007-01-01

    The ability to read head-fixed displays on various motion platforms requires the suppression of vestibulo-ocular reflexes. This study examined dynamic visual acuity while viewing a head-fixed display during different self and surround rotation conditions. Twelve healthy subjects were asked to report the orientation of Landolt C optotypes presented on a micro-display fixed to a rotating chair at 50 cm distance. Acuity thresholds were determined by the lowest size at which the subjects correctly identified 3 of 5 optotype orientations at peak velocity. Visual acuity was compared across four different conditions, each tested at 0.05 and 0.4 Hz (peak amplitude of 57 deg/s). The four conditions included: subject rotated in semi-darkness (i.e., limited to background illumination of the display), subject stationary while visual scene rotated, subject rotated around a stationary visual background, and both subject and visual scene rotated together. Visual acuity performance was greatest when the subject rotated around a stationary visual background; i.e., when both vestibular and visual inputs provided concordant information about the motion. Visual acuity performance was most reduced when the subject and visual scene rotated together; i.e., when the visual scene provided discordant information about the motion. Ranges of 4-5 logMAR step sizes across the conditions indicated the acuity task was sufficient to discriminate visual performance levels. The background visual scene can influence the ability to read head-fixed displays during passive motion disturbances. Dynamic visual acuity using head-fixed displays can provide an operationally relevant screening tool for visual performance during exposure to novel acceleration environments.

  19. The impact of visual acuity on age-related differences in neural markers of early visual processing.

    Science.gov (United States)

    Daffner, Kirk R; Haring, Anna E; Alperin, Brittany R; Zhuravleva, Tatyana Y; Mott, Katherine K; Holcomb, Phillip J

    2013-02-15

    The extent to which age-related differences in neural markers of visual processing are influenced by changes in visual acuity has not been systematically investigated. Studies often indicate that their subjects had normal or corrected-to-normal vision, but the assessment of visual acuity seems to most frequently be based only on self-report. Consistent with prior research, to be included in the current study, subjects had to report normal or corrected-to-normal vision. Additionally, visual acuity was formally tested using a Snellen eye chart. Event-related potentials (ERPs) were studied in young adults (18-32years old), young-old adults (65-79years old), and old-old adults (80+ years old) while they performed a visual processing task involving selective attention to color. Age-related differences in the latency and amplitude of ERP markers of early visual processing, the posterior P1 and N1 components, were examined. All results were then re-analyzed after controlling for visual acuity. We found that visual acuity declined as a function of age. Accounting for visual acuity had an impact on whether older and younger adults differed significantly in the size and latency of the posterior P1 and N1 components. After controlling for visual acuity, age-related increases in P1 and N1 latency did not remain significant, and older adults were found to have a larger P1 amplitude than young adults. Our results suggest that until the relationship between age-associated differences in visual acuity and early ERPs is clearly established, investigators should be cautious when interpreting the meaning of their findings. Self-reports about visual acuity may be inaccurate, necessitating formal measures. Additional investigation is needed to help establish guidelines for future research, especially of very old adults.

  20. Influence of different types of astigmatism on visual acuity.

    Science.gov (United States)

    Remón, Laura; Monsoriu, Juan A; Furlan, Walter D

    To investigate the change in visual acuity (VA) produced by different types of astigmatism (on the basis of the refractive power and position of the principal meridians) on normal accommodating eyes. The lens induced method was employed to simulate a set of 28 astigmatic blur conditions on different healthy emmetropic eyes. Additionally, 24 values of spherical defocus were also simulated on the same eyes for comparison. VA was measured in each case and the results, expressed in logMAR units, were represented against of the modulus of the dioptric power vector (blur strength). LogMAR VA varies in a linear fashion with increasing astigmatic blur, being the slope of the line dependent on the accommodative demand in each type of astigmatism. However, in each case, we found no statistically significant differences between the three axes investigated (0°, 45°, 90°). Non-statistically significant differences were found either for the VA achieved with spherical myopic defocus (MD) and mixed astigmatism (MA). VA with simple hyperopic astigmatism (SHA) was higher than with simple myopic astigmatism (SMA), however, in this case non conclusive results were obtained in terms of statistical significance. The VA achieved with imposed compound hyperopic astigmatism (CHA) was highly influenced by the eye's accommodative response. VA is correlated with the blur strength in a different way for each type of astigmatism, depending on the accommodative demand. VA is better when one of the focal lines lie on the retina irrespective of the axis orientation; accommodation favors this situation. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  1. Incorporating a Wheeled Vehicle Model in a New Monocular Visual Odometry Algorithm for Dynamic Outdoor Environments

    Directory of Open Access Journals (Sweden)

    Yanhua Jiang

    2014-09-01

    Full Text Available This paper presents a monocular visual odometry algorithm that incorporates a wheeled vehicle model for ground vehicles. The main innovation of this algorithm is to use the single-track bicycle model to interpret the relationship between the yaw rate and side slip angle, which are the two most important parameters that describe the motion of a wheeled vehicle. Additionally, the pitch angle is also considered since the planar-motion hypothesis often fails due to the dynamic characteristics of wheel suspensions and tires in real-world environments. Linearization is used to calculate a closed-form solution of the motion parameters that works as a hypothesis generator in a RAndom SAmple Consensus (RANSAC scheme to reduce the complexity in solving equations involving trigonometric. All inliers found are used to refine the winner solution through minimizing the reprojection error. Finally, the algorithm is applied to real-time on-board visual localization applications. Its performance is evaluated by comparing against the state-of-the-art monocular visual odometry methods using both synthetic data and publicly available datasets over several kilometers in dynamic outdoor environments.

  2. Sighting dominance, handedness, and visual acuity preference: three mutually exclusive modalities?

    Science.gov (United States)

    Pointer, J S

    2001-03-01

    It is tempting, even perhaps for the clinician, to assume prima facie that an individual's handedness is indicative of other lateral asymmetries, including ocular (sighting) dominance and preferred monocular acuity. An analysis of new data relating to these three modalities, as collated from counter-balanced groups of normally sighted male and female children and adults examined in optometric practice, confirms the general fallacy of this assumption and considers why it is such a persistent misconception. The degree of association between the three modalities in right-preferent individuals is revealed as statistically no greater than chance. On the basis of this study, estimates of right-sided hand, eye and/or acuity congruency are derived for the information of the clinician in the prescribing environment of the consulting room.

  3. Functional visual acuity in patients with successfully treated amblyopia: a pilot study.

    Science.gov (United States)

    Hoshi, Sujin; Hiraoka, Takahiro; Kotsuka, Junko; Sato, Yumiko; Izumida, Shinya; Kato, Atsuko; Ueno, Yuta; Fukuda, Shinichi; Oshika, Tetsuro

    2017-06-01

    The aim of this study was to use conventional visual acuity measurements to quantify the functional visual acuity (FVA) in eyes with successfully treated amblyopia, and to compare the findings with those for contralateral normal eyes. Nineteen patients (7 boys, 12 girls; age 7.5 ± 2.2 years) with successfully treated unilateral amblyopia and the same conventional decimal visual acuity in both eyes (better than 1.0) were enrolled. FVA, the visual maintenance ratio (VMR), maximum and minimum visual acuity, and the average response time were recorded for both eyes of all patients using an FVA measurement system. The differences in FVA values between eyes were analyzed. The mean LogMAR FVA scores, VMR (p amblyopia than for the contralateral normal eyes. There was no significant difference in the average response time. Our results indicate that FVA and VMR were poorer for eyes with treated amblyopia than for normal eyes, even though the treatment for amblyopia was considered successful on the basis of conventional visual acuity measurements. These results suggest that visual function is impaired in eyes with amblyopia, regardless of treatment success, and that FVA measurements can provide highly valuable diagnosis and treatment information that is not readily provided by conventional visual acuity measurements.

  4. Night vision goggle visual acuity assessment: results of an interagency test

    Science.gov (United States)

    Task, H. Lee

    2001-08-01

    There are several parameters that are used to characterize the quality of a night vision goggle (NVG) such as resolution, gain, field-of-view, visual acuity, etc. One of the primary parameters is visual acuity or resolution of the NVG. These two terms are often used interchangeably primarily because of the measurement methods employed. The objectives of this paper are to present: (1) an argument as to why NVG visual acuity and resolution should be considered as distinctly different parameters, (2) descriptions of different methods of measuring visual acuity and resolution, and (3) the results of a blind test by several agencies to measure the resolution of the same two NVGs (four oculars).

  5. A new Gujarati language logMAR visual acuity chart: Development and validation

    OpenAIRE

    Ananth Sailoganathan; John Siderov; Ebi Osuobeni

    2013-01-01

    Aims: Gujarati is the main spoken language of a large proportion of the population of India. The aim of this study was to develop and validate a new Minimum Angle of Resolution (logMAR) visual acuity chart in the Gujarati language. Materials and Methods: A new Gujarati visual acuity chart was designed to logMAR specifications using Gujarati optotypes experimentally selected to have similar relative letter legibility under spherical and cylindrical defocus. The chart validation study was carri...

  6. The Effect of Signal-to-Noise Ratio on Visual Acuity Through Night Vision Goggles

    Science.gov (United States)

    1991-02-01

    subjects in visuLal acuity performance with NVGs, it was concluded that further research should be conducted to examine the correlation between visual...the image intensifier tuho. Tile image intensifier tube is basically a light amplifier that is sensitive over tho spectral region of about 600nm to... excellent means of getting a sensitive measure of visual acuity. 2 Method 2.1 Subje;cts Twelve male volunteers participated in this study. ’he subjects

  7. Comparison of visual acuity estimates using three different letter charts under two ambient room illuminations

    Directory of Open Access Journals (Sweden)

    Ai-Hong Chen

    2012-01-01

    Full Text Available Background: Visual acuity is an essential estimate to assess ability of the visual system and is used as an indicator of ocular health status. Aim: The aim of this study is to investigate the consistency of acuity estimates from three different clinical visual acuity charts under two levels of ambient room illumination. Materials and Methods: This study involved thirty Malay university students aged between 19 and 23 years old (7 males, 23 females, with their spherical refractive error ranging between plano and −7.75D, astigmatism ranging from plano to −1.75D, anisometropia less than 1.00D and with no history of ocular injury or pathology. Right eye visual acuity (recorded in logMAR unit was measured with Snellen letter chart (Snellen, wall mounted letter chart (WM and projected letter chart (PC under two ambient room illuminations, room light on and room light off. Results: Visual acuity estimates showed no statistically significant difference when measured with the room light on and with the room light off (F1,372 = 0.26, P = 0.61. Post-hoc analysis with Tukey showed that visual acuity estimates were significantly different between the Snellen and PC (P = 0.009 and between Snellen and WM (P = 0.002. Conclusions: Different levels of ambient room illumination had no significant effect on visual acuity estimates. However, the discrepancies in estimates of visual acuity noted in this study were purely due to the type of letter chart used.

  8. Use of optical coherence tomography to evaluate visual acuity and visual field changes in dengue fever.

    Science.gov (United States)

    Rhee, Taek Kwan; Han, Jung Il

    2014-02-01

    Dengue fever is a viral disease that is transmitted by mosquitoes and affects humans. In rare cases, dengue fever can cause visual impairment, which usually occurs within 1 month after contracting dengue fever and ranges from mild blurring of vision to severe blindness. Visual impairment due to dengue fever can be detected through angiography, retinography, optical coherence tomography (OCT) imaging, electroretinography, event electroencephalography (visually evoked potentials), and visual field analysis. The purpose of this study is to report changes in the eye captured using fluorescein angiography, indocyanine green, and OCT in 3 cases of dengue fever visual impairment associated with consistent visual symptoms and similar retinochoroidopathic changes. The OCT results of the three patients with dengue fever showed thinning of the outer retinal layer and disruption of the inner segment/outer segment (IS/OS) junction. While thinning of the retina outer layer is an irreversible process, disruption of IS/OS junction is reported to be reversible. Follow-up examination of individuals with dengue fever and associated visual impairment should involve the use of OCT to evaluate visual acuity and visual field changes in patients with acute choroidal ischemia.

  9. Crowding and visual acuity measured in adults using paediatric test letters, pictures and symbols.

    Science.gov (United States)

    Lalor, Sarah J H; Formankiewicz, Monika A; Waugh, Sarah J

    2016-04-01

    Crowding refers to the degradation of visual acuity for target optotypes with, versus without, surrounding features. Crowding is important clinically, however the effect of target-flanker spacing on acuity for symbols and pictures, compared to letters, has not been investigated. Five adults with corrected-to-normal vision had visual acuity measured for modified single target versions of Kay Pictures, Lea Symbols, HOTV and Cambridge Crowding Cards, tests. Single optotypes were presented in isolation and with surrounding features placed 0-5 stroke-widths away. Visual acuity measured with Kay Picture optotypes is 0.13-0.19logMAR better than for other test optotypes and varies significantly across picture. The magnitude of crowding is strongest when the surrounding features abut, or are placed 1 stroke-width away from the target optotype. The slope of the psychometric function is steeper in the region just beyond maximum crowding. Crowding is strongest and the psychometric function steepest, with the Cambridge Crowding Cards arrangement, than when any single optotype is surrounded by a box. Estimates of crowding extent are less variable across test when expressed in units of stroke-width, than optotype-width. Crowding for single target presentations of letters, symbols and pictures used in paediatric visual acuity tests can be maximised and made more sensitive to change in visual acuity, by careful selection of optotype, by surrounding the target with similar flankers, and by using a closer target-flanker separation than half an optotype-width.

  10. Forward light scatter and visual acuity before and after intrastromal corneal ring segment implantation at different stages of keratoconus.

    Science.gov (United States)

    Puell, María Cinta; Carballo-Álvarez, Jesús

    2016-12-01

    To assess forward light scatter (stray light) before and after intrastromal corneal ring segment (ICRS) implantation at different stages of keratoconus and to examine correlation between postoperative stray light and visual acuity (VA). In 27 eyes of 27 subjects with keratoconus, stray light was determined using the compensation comparison technique before and 6 months after ICRS implantation. Monocular corrected distance VA (CDVA) was measured using a high-contrast logMAR letter chart. Corneal higher-order aberrations (HOAs), contrast sensitivity (CS) and minimum corneal thickness (CT) were also measured. Mean CDVA was 0.42 ± 0.28 preoperatively and 0.24 ± 0.15 logMAR postoperatively (p  0.05) for stage I, 0.13 ± 0.14 (p = 0.013) for stage II and 0.18 ± 0.21 (p = 0.023) for stage III. Significant positive correlation (r = 0.47, p = 0.01) was detected between postoperative stray light and postoperative CDVA such that as stray light increased, CDVA worsened (higher logMAR values). Postoperative stray light was neither associated with HOAs, CS nor minimum CT. Stray light values in these patients with keratoconus were higher than normal preoperatively. In eyes with stage II and III keratoconus, stray light increased 6 months after ICRS placement. Higher postoperative stray light was correlated with a worse visual acuity outcome. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  11. Laser refractive correction of myopia in visually impaired patients improves visual acuity.

    Science.gov (United States)

    Vuori, Elisa; Tervo, Timo M T; Holopainen, Juha M

    2011-09-01

    To retrospectively evaluate the visual and refractive outcome of visually impaired adults treated with refractive surgery (photorefractive keratectomy or laser-assisted in situ keratomileusis). We searched a refractive surgery database comprising 1716 mildly visually impaired patients [best spectacle-corrected visual acuity (BSCVA) on a logMAR scale ≤ -0.1 (Snellen ≤ 0.8)] who had undergone either PRK or LASIK (n = 96). PRK patients who had visits at 5-7, 8-13 and 14-24 months postoperatively were selected. Eleven patients and nine PRK control myopic patients were found (cohort 1). From the same database, 41 visually impaired patients and 54 controls who had a postoperative control at 14-24 months postoperatively were chosen. These patients formed cohort 2. Preoperatively, in cohort 1, the mean BSCVA on a logMAR scale was -0.15 ± 0.13 (Snellen 0.73 ± 0.16) in visually impaired patients and 0.04 ± 0.02 (Snellen 1.11 ± 0.17) in myopic controls. At 14-24 months postoperatively, the mean BSCVA improved to 0.05 ± 0.04 (Snellen 1.13 ± 0.10) in visually impaired patients and 0.05 ± 0.08 (Snellen 1.13 ± 0.21) in control patients. In cohort 2, preoperatively the mean BSCVA on a logMAR scale was -0.15 ± 0.12 (Snellen 0.74 ± 0.14) in visually impaired patients and 0.01 ± 0.03 (Snellen 1.04 ± 0.10) in myopic controls. At 14-24 months postoperatively, the mean BSCVA improved to 0.02 ± 0.07 (Snellen 1.06 ± 0.16) in visually impaired patients and 0.06 ± 0.06 (Snellen 1.15 ± 0.16) in control patients. Refractive surgery improves BSCVA in visually impaired patients, possibly through plastic changes in the visual cortex. Consequently, refractive surgery may be used successfully for the treatment of visually impaired adults to enhance their visual acuity. © 2009 The Authors. Journal compilation © 2009 Acta Ophthalmol.

  12. Comparison of Snellen and interferometer visual acuity in an aging noncataractous population.

    Science.gov (United States)

    Geddes, L A; Patel, B J; Bradley, A

    1990-05-01

    Using standard clinical procedures we have compared visual acuity (VA) estimates made with a hand-held white light interferometer to those obtained with a Snellen acuity chart. Fifty noncataractous patients with a mean age of 45 years (SD = 18) were tested. Snellen and interferometric acuity measures were obtained with and without refractive correction. On average, aided Snellen VA's were better (decimal acuity = 0.98) than the unaided interferometric VA's (decimal acuity = 0.67). Although we found a statistically significant p less than 0.01) correlation between unaided interferometric and aided Snellen VA's, the correlation was poor (r = 0.36). This poor correlation may account for the often observed failure to estimate postoperative aided Snellen VA with preoperative interferometric VA in cataract patients.

  13. Effects of molting on the visual acuity of the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Baldwin, Jamie; Johnsen, Sönke

    2011-09-15

    In crustaceans with compound eyes, the corneal lens of each facet is part of the exoskeleton and thus shed during molting. Here we used an optomotor assay to evaluate the impact of molting on visual acuity (as measured by the minimum resolvable angle, α(min)) in the female blue crab, Callinectes sapidus. We found that visual acuity decreases substantially in the days prior to molting and is gradually recovered after molting. Four days prior to molting, α(min) was 1.8 deg (N=5), a value approximating the best possible acuity in this species. In the 24 h before ecdysis occurred, α(min) increased to 15.0 deg (N=12), corresponding to an eightfold drop in visual acuity. Within 6 days after molting, α(min) returned to the pre-molting value. Micrographs of C. sapidus eyes showed that a gap between the corneal lens and the crystalline cone first appeared approximately 5 days prior to shedding and increased in width as the process progressed. This separation was likely responsible for the loss of visual acuity observed in behavioral tests. In blue crabs, mating is limited to the period of the female's pubertal molt, and a reduction in acuity during this time may have an effect on the sensory cues used in female mate choice. The results described here may be broadly applicable to all arthropods that molt and have particular importance for crustaceans that molt multiple times in their lifetime or have mating cycles that are paired with molting.

  14. A new Gujarati language logMAR visual acuity chart: development and validation.

    Science.gov (United States)

    Sailoganathan, Ananth; Siderov, John; Osuobeni, Ebi

    2013-10-01

    Gujarati is the main spoken language of a large proportion of the population of India. The aim of this study was to develop and validate a new Minimum Angle of Resolution (logMAR) visual acuity chart in the Gujarati language. A new Gujarati visual acuity chart was designed to logMAR specifications using Gujarati optotypes experimentally selected to have similar relative letter legibility under spherical and cylindrical defocus. The chart validation study was carried out using 153 adult subjects in a large clinical setting in India. Subjects who were literate in English and Gujarati participated in the study. Visual acuity was measured with the new Gujarati logMAR chart and a modified Early Treatment of Diabetic Retinopathy Study-(m-ETDRS) logMAR chart. The method of presentation was randomized between the charts. Repeat visual acuity was measured on a subsequent day with a second version of the Gujarati logMAR chart. The Gujarati chart correlated highly with the m-ETDRS logMAR chart (r² = 0.974). The mean visual acuity difference (Gujarati - m-ETDRS logMAR) was equal to three letters (-0.06 logMAR). The Gujarati logMAR chart also proved to be highly repeatable (r² = 0.994, test-retest) with 95% CI of ± 0.04 logMAR. The new Gujarati logMAR visual acuity chart provides a valid and repeatable tool for the measurement of visual acuity in native Gujarati language speakers.

  15. A new Gujarati language logMAR visual acuity chart: Development and validation

    Directory of Open Access Journals (Sweden)

    Ananth Sailoganathan

    2013-01-01

    Full Text Available Aims: Gujarati is the main spoken language of a large proportion of the population of India. The aim of this study was to develop and validate a new Minimum Angle of Resolution (logMAR visual acuity chart in the Gujarati language. Materials and Methods: A new Gujarati visual acuity chart was designed to logMAR specifications using Gujarati optotypes experimentally selected to have similar relative letter legibility under spherical and cylindrical defocus. The chart validation study was carried out using 153 adult subjects in a large clinical setting in India. Subjects who were literate in English and Gujarati participated in the study. Visual acuity was measured with the new Gujarati logMAR chart and a modified Early Treatment of Diabetic Retinopathy Study-(m-ETDRS logMAR chart. The method of presentation was randomized between the charts. Repeat visual acuity was measured on a subsequent day with a second version of the Gujarati logMAR chart. Results: The Gujarati chart correlated highly with the m-ETDRS logMAR chart (r2 = 0.974. The mean visual acuity difference (Gujarati - m-ETDRS logMAR was equal to three letters (-0.06 logMAR. The Gujarati logMAR chart also proved to be highly repeatable (r2 = 0.994, test-retest with 95% CI of ± 0.04 logMAR. Conclusions: The new Gujarati logMAR visual acuity chart provides a valid and repeatable tool for the measurement of visual acuity in native Gujarati language speakers.

  16. Modelling Cost Effectiveness in Neovascular Age-Related Macular Degeneration: The Impact of Using Contrast Sensitivity vs. Visual Acuity.

    OpenAIRE

    Butt, T.; Patel,P J; Tufail, A; Rubin, G. S.

    2014-01-01

    The cost utility of treatments of age-related macular degeneration (AMD) is commonly assessed using health state transition models defined by levels of visual acuity. However, there is evidence that another measure of visual function, contrast sensitivity, may be better associated with utility than visual acuity. This paper investigates the difference in cost effectiveness resulting from models based on visual acuity and contrast sensitivity using the example of bevacizumab (Avastin) for neov...

  17. Through the Neural Magnifying Glass: Visual Acuity and Motion-Aftereffect

    Directory of Open Access Journals (Sweden)

    S.C Boyle

    2014-08-01

    Full Text Available A Sloan- or Snellen-type visual acuity chart is commonly used for routine eye examination. This test serves as a benchmark for visual acuity where observers read out letters of decreasing size at a recommended viewing distance. The smallest readable letter size is typically used as a measure of visual acuity. For example, vision of 20/20 and 10/10 describe the ability to resolve letters that subtend 5 minutes of arc at a viewing distance of 20 (6m and 10 feet (3m, respectively. Here we show that adaptation to a rotating spiral and the ensuing motion aftereffect (MAE significantly alters visual acuity in normal observers. In one group 44 observers adapted to contracting motion and in a second group 30 observers adapted to expanding motion. The results clearly demonstrate that the expanding MAE facilitated subsequent letter recognition whereas the contracting MAE impaired letter recognition. We conclude that illusory expansion enlarges the apparent size of letters thereby increasing perceptual fields and number of feature detectors. Illusory contraction on the other hand reduces the apparent size of the letters thereby decreasing perceptual fields and number of feature detectors. It is an astonishing characteristic of the visual system that motion adaptation can improve visual acuity – a measure that is typically related to the optics of the eye rather than feature recognition and cognitive inference

  18. Visual Temporal Acuity Is Related to Auditory Speech Perception Abilities in Cochlear Implant Users.

    Science.gov (United States)

    Jahn, Kelly N; Stevenson, Ryan A; Wallace, Mark T

    Despite significant improvements in speech perception abilities following cochlear implantation, many prelingually deafened cochlear implant (CI) recipients continue to rely heavily on visual information to develop speech and language. Increased reliance on visual cues for understanding spoken language could lead to the development of unique audiovisual integration and visual-only processing abilities in these individuals. Brain imaging studies have demonstrated that good CI performers, as indexed by auditory-only speech perception abilities, have different patterns of visual cortex activation in response to visual and auditory stimuli as compared with poor CI performers. However, no studies have examined whether speech perception performance is related to any type of visual processing abilities following cochlear implantation. The purpose of the present study was to provide a preliminary examination of the relationship between clinical, auditory-only speech perception tests, and visual temporal acuity in prelingually deafened adult CI users. It was hypothesized that prelingually deafened CI users, who exhibit better (i.e., more acute) visual temporal processing abilities would demonstrate better auditory-only speech perception performance than those with poorer visual temporal acuity. Ten prelingually deafened adult CI users were recruited for this study. Participants completed a visual temporal order judgment task to quantify visual temporal acuity. To assess auditory-only speech perception abilities, participants completed the consonant-nucleus-consonant word recognition test and the AzBio sentence recognition test. Results were analyzed using two-tailed partial Pearson correlations, Spearman's rho correlations, and independent samples t tests. Visual temporal acuity was significantly correlated with auditory-only word and sentence recognition abilities. In addition, proficient CI users, as assessed via auditory-only speech perception performance, demonstrated

  19. Is acuity enough? Other considerations in clinical investigations of visual prostheses.

    Science.gov (United States)

    Lepri, Bernard P

    2009-06-01

    Visual impairing eye diseases are the major frontier facing ophthalmic research today in light of our rapidly aging population. The visual skills necessary for improving the quality of daily function and life are inextricably linked to these impairing diseases. Both research and reimbursement programs are emphasizing outcome-based results. Is improvement in visual acuity alone enough to improve the function and quality of life of visually impaired persons? This perspective summarizes the types of effectiveness endpoints for clinical investigations of visual prostheses that go beyond visual acuity. The clinical investigation of visual prostheses should include visual function, functional vision and quality of life measures. Specifically, they encompass contrast sensitivity, orientation and mobility, activities of daily living and quality of life assessments. The perspective focuses on the design of clinical trials for visual prostheses and the methods of determining effectiveness above and beyond visual acuity that will yield outcomes that are measured by improved function in the visual world and quality of life. The visually impaired population is the primary consideration in this presentation with particular emphases on retinitis pigmentosa and age-related macular degeneration. Clinical trials for visual prostheses cannot be isolated from the need for medical rehabilitation in order to obtain measurements of effectiveness that produce outcomes/evidence-based success. This approach will facilitate improvement in daily function and quality of life of patients with diseases that cause chronic vision impairment.

  20. Comparison of visual acuity measured with Allen figures and Snellen letters using the B-VAT II monitor.

    Science.gov (United States)

    Lueder, G T; Garibaldi, D

    1997-11-01

    Allen figure optotypes commonly are used to measure visual acuity in young children. Children with normal acuity measured with Allen figures sometimes are found to have unsuspected amblyopia that is detected when they are tested with Snellen letters. The correlation between visual acuities measured with these two optotype charts has not been well studied. The authors compared visual acuities measured with Allen figure and Snellen letter optotypes using the Mentor B-VAT II monitor. The study design was a nonrandomized, comparative clinical trial. The study was composed of 12 adult subjects. Visual acuities were measured using both Allen figure and Snellen letter optotypes using the B-VAT II monitor. The images were progressively blurred using plus lenses. Visual acuity was measured. At visual acuity levels of 20/60 or better, Allen figure testing averaged 1.5 lines better than Snellen letter testing; between 20/70 and 20/200 visual acuities, the difference was 2.5 lines. Allen figure testing with the B-VAT II monitor overestimates visual acuity compared with testing with Snellen letters. This appears to result primarily from the construction of the optotypes. This discrepancy should be considered when visual acuity is measured in young children.

  1. Visual system plasticity in mammals: the story of monocular enucleation-induced vision loss.

    Science.gov (United States)

    Nys, Julie; Scheyltjens, Isabelle; Arckens, Lutgarde

    2015-01-01

    The groundbreaking work of Hubel and Wiesel in the 1960's on ocular dominance plasticity instigated many studies of the visual system of mammals, enriching our understanding of how the development of its structure and function depends on high quality visual input through both eyes. These studies have mainly employed lid suturing, dark rearing and eye patching applied to different species to reduce or impair visual input, and have created extensive knowledge on binocular vision. However, not all aspects and types of plasticity in the visual cortex have been covered in full detail. In that regard, a more drastic deprivation method like enucleation, leading to complete vision loss appears useful as it has more widespread effects on the afferent visual pathway and even on non-visual brain regions. One-eyed vision due to monocular enucleation (ME) profoundly affects the contralateral retinorecipient subcortical and cortical structures thereby creating a powerful means to investigate cortical plasticity phenomena in which binocular competition has no vote.In this review, we will present current knowledge about the specific application of ME as an experimental tool to study visual and cross-modal brain plasticity and compare early postnatal stages up into adulthood. The structural and physiological consequences of this type of extensive sensory loss as documented and studied in several animal species and human patients will be discussed. We will summarize how ME studies have been instrumental to our current understanding of the differentiation of sensory systems and how the structure and function of cortical circuits in mammals are shaped in response to such an extensive alteration in experience. In conclusion, we will highlight future perspectives and the clinical relevance of adding ME to the list of more longstanding deprivation models in visual system research.

  2. Single spot PDT in patients with circumscribed choroidal haemangioma and near normal visual acuity

    NARCIS (Netherlands)

    F.D. Verbraak; R.O. Schlingemann; M.D. de Smet; J.E.E. Keunen

    2006-01-01

    Background: In circumscribed choroidal hemangiomas (CCH) a long observation period and decreased visual acuity before treatment are risk factors for poor visual outcome. Therefore, we studied the use of limited, single spot photodynamic therapy (PDT) with Visudyne for the timely treatment of CCH. Me

  3. Single spot PDT in patients with circumscribed choroidal haemangioma and near normal visual acuity.

    NARCIS (Netherlands)

    Verbraak, F.D.; Schlingemann, R.O.; Smet, M.D. de; Keunen, J.E.E.

    2006-01-01

    BACKGROUND: In circumscribed choroidal hemangiomas (CCH) a long observation period and decreased visual acuity before treatment are risk factors for poor visual outcome. Therefore, we studied the use of limited, single spot photodynamic therapy (PDT) with Visudyne for the timely treatment of CCH. ME

  4. Screening for Impaired Visual Acuity in Older Adults : US Preventive Services Task Force Recommendation Statement

    NARCIS (Netherlands)

    Calonge, Ned; Petitti, Diana B.; DeWitt, Thomas G.; Dietrich, Allen J.; Gregory, Kimberly D.; Grossman, David; Isham, George; LeFevre, Michael L.; Leipzig, Rosanne M.; Marion, Lucy N.; Melnyk, Bernadette; Moyer, Virginia A.; Ockene, Judith K.; Sawaya, George F.; Schwartz, J. Sanford; Wilt, Timothy

    2009-01-01

    Description: Update of the 1996 U. S. Preventive Services Task Force (USPSTF) recommendation statement on screening for visual impairment. Methods: The USPSTF reviewed evidence published since its last review on screening adults 65 years or older in the primary care setting for visual acuity impairm

  5. Screening for Impaired Visual Acuity in Older Adults : US Preventive Services Task Force Recommendation Statement

    NARCIS (Netherlands)

    Calonge, Ned; Petitti, Diana B.; DeWitt, Thomas G.; Dietrich, Allen J.; Gregory, Kimberly D.; Grossman, David; Isham, George; LeFevre, Michael L.; Leipzig, Rosanne M.; Marion, Lucy N.; Melnyk, Bernadette; Moyer, Virginia A.; Ockene, Judith K.; Sawaya, George F.; Schwartz, J. Sanford; Wilt, Timothy

    2009-01-01

    Description: Update of the 1996 U. S. Preventive Services Task Force (USPSTF) recommendation statement on screening for visual impairment. Methods: The USPSTF reviewed evidence published since its last review on screening adults 65 years or older in the primary care setting for visual acuity impairm

  6. Bevacizumab Injection in Patients with Age-Related Macular Degeneration Associated with Poor Initial Visual Acuity

    Directory of Open Access Journals (Sweden)

    Leila El Matri

    2012-01-01

    Full Text Available Purpose. To evaluate functional and anatomic effects of intravitreal bevacizumab in patients with neovascular AMD and initial low visual acuity. Methods. Retrospective case series of 38 eyes with neovascular AMD and initial visual acuity of 20/200 or less, treated with intravitreal bevacizumab injection. Results. Mean followup was 14.1 months ±7.1 (range: 5 to 24 months. Mean logMAR vision at baseline was 1.38 logMAR ±0.33, at 6 months was 1.14 logMAR ±0.37 (=0.001 and at 12 months was 1.22 logMar ±0.33 (=0.004. Mean baseline central retinal thickness was 431 μm ±159.7 at 6 months was 293.43 μm  ±122.79 (=10−4 and at 12 months was 293.1 μm  ±130 (=0.004. Visual acuity improved in both patients with or without prior PDT treatment. Conclusions. Intravitreal bevacizumab injection may increase the chance of visual acuity gain in neovascular AMD even in cases with initial low visual acuity.

  7. Bevacizumab injection in patients with age-related macular degeneration associated with poor initial visual acuity.

    Science.gov (United States)

    El Matri, Leila; Bouraoui, Rym; Chebil, Ahmed; Kort, Fedra; Bouladi, Mejda; Limaiem, Rym; Landoulsi, Hana

    2012-01-01

    Purpose. To evaluate functional and anatomic effects of intravitreal bevacizumab in patients with neovascular AMD and initial low visual acuity. Methods. Retrospective case series of 38 eyes with neovascular AMD and initial visual acuity of 20/200 or less, treated with intravitreal bevacizumab injection. Results. Mean followup was 14.1 months ±  7.1 (range: 5 to 24 months). Mean logMAR vision at baseline was 1.38 logMAR ±  0.33, at 6 months was 1.14 logMAR ±  0.37 (P = 0.001) and at 12 months was 1.22 logMar ±  0.33 (P = 0.004). Mean baseline central retinal thickness was 431 μm ±  159.7 at 6 months was 293.43 μm  ±  122.79 (P = 10(-4)) and at 12 months was 293.1 μm  ±  130 (P = 0.004). Visual acuity improved in both patients with or without prior PDT treatment. Conclusions. Intravitreal bevacizumab injection may increase the chance of visual acuity gain in neovascular AMD even in cases with initial low visual acuity.

  8. Gender and environmental influences on visual acuity in Owerri ...

    African Journals Online (AJOL)

    olayemitoyin

    Summary: This study assessed the gender and environmental influences on visual ... Visual disability together with other ... prevalence of reduced VA was higher among ametropics and rural dwellers. ... Health education on diet, drug use.

  9. The perceived visual direction of monocular objects in random-dot stereograms is influenced by perceived depth and allelotropia.

    Science.gov (United States)

    Hariharan-Vilupuru, Srividhya; Bedell, Harold E

    2009-01-01

    The proposed influence of objects that are visible to both eyes on the perceived direction of an object that is seen by only one eye is known as the "capture of binocular visual direction". The purpose of this study was to evaluate whether stereoscopic depth perception is necessary for the "capture of binocular visual direction" to occur. In one pair of experiments, perceived alignment between two nearby monocular lines changed systematically with the magnitude and direction of horizontal but not vertical disparity. In four of the five observers, the effect of horizontal disparity on perceived alignment depended on which eye viewed the monocular lines. In additional experiments, the perceived alignment between the monocular lines changed systematically with the magnitude and direction of both horizontal and vertical disparities when the monocular line separation was increased from 1.1 degrees to 3.3 degrees . These results indicate that binocular capture depends on the perceived depth that results from horizontal retinal image disparity as well as allelotropia, or the averaging of local-sign information. Our data suggest that, during averaging, different weights are afforded to the local-sign information in the two eyes, depending on whether the separation between binocularly viewed targets is horizontal or vertical.

  10. Monocular SLAM for Visual Odometry: A Full Approach to the Delayed Inverse-Depth Feature Initialization Method

    Directory of Open Access Journals (Sweden)

    Rodrigo Munguía

    2012-01-01

    Full Text Available This paper describes in a detailed manner a method to implement a simultaneous localization and mapping (SLAM system based on monocular vision for applications of visual odometry, appearance-based sensing, and emulation of range-bearing measurements. SLAM techniques are required to operate mobile robots in a priori unknown environments using only on-board sensors to simultaneously build a map of their surroundings; this map will be needed for the robot to track its position. In this context, the 6-DOF (degree of freedom monocular camera case (monocular SLAM possibly represents the harder variant of SLAM. In monocular SLAM, a single camera, which is freely moving through its environment, represents the sole sensory input to the system. The method proposed in this paper is based on a technique called delayed inverse-depth feature initialization, which is intended to initialize new visual features on the system. In this work, detailed formulation, extended discussions, and experiments with real data are presented in order to validate and to show the performance of the proposal.

  11. c-FOS expression in the visual system of tree shrews after monocular inactivation.

    Science.gov (United States)

    Takahata, Toru; Kaas, Jon H

    2017-01-01

    Tree shrews possess an unusual segregation of ocular inputs to sublayers rather than columns in the primary visual cortex (V1). In this study, the lateral geniculate nucleus (LGN), superior colliculus (SC), pulvinar, and V1 were examined for changes in c-FOS, an immediate-early gene, expression after 1 or 24 hours of monocular inactivation with tetrodotoxin (TTX) in tree shrews. Monocular inactivation greatly reduced gene expression in LGN layers related to the blocked eye, whereas normally high to moderate levels were maintained in the layers that receive inputs from the intact eye. The SC and caudal pulvinar contralateral to the blocked eye had greatly (SC) or moderately (pulvinar) reduced gene expressions reflective of dependence on the contralateral eye. c-FOS expression in V1 was greatly reduced contralateral to the blocked eye, with most of the expression that remained in upper layer 4a and lower 4b and lower layer 6 regions. In contrast, much of V1 contralateral to the active eye showed normal levels of c-FOS expression, including the inner parts of sublayers 4a and 4b and layers 2, 3, and 6. In some cases, upper layer 4a and lower 4b showed a reduction of gene expression. Layers 5 and sublayer 3c had normally low levels of gene expression. The results reveal the functional dominance of the contralateral eye in activating the SC, pulvinar, and V1, and the results from V1 suggest that the sublaminar organization of layer 4 is more complex than previously realized. J. Comp. Neurol. 525:151-165, 2017. © 2016 Wiley Periodicals, Inc.

  12. Brief monocular deprivation as an assay of short-term visual sensory plasticity in schizophrenia – the binocular effect.

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    John J Foxe

    2013-12-01

    Full Text Available Background: Visual sensory processing deficits are consistently observed in schizophrenia, with clear amplitude reduction of the visual evoked potential (VEP during the initial 50-150 milliseconds of processing. Similar deficits are seen in unaffected first-degree relatives and drug-naïve first-episode patients, pointing to these deficits as potential endophenotypic markers. Schizophrenia is also associated with deficits in neural plasticity, implicating dysfunction of both glutamatergic and gabaergic systems. Here, we sought to understand the intersection of these two domains, asking whether short-term plasticity during early visual processing is specifically affected in schizophrenia. Methods: Brief periods of monocular deprivation induce relatively rapid changes in the amplitude of the early VEP – i.e. short-term plasticity. Twenty patients and twenty non-psychiatric controls participated. VEPs were recorded during binocular viewing, and were compared to the sum of VEP responses during brief monocular viewing periods (i.e. Left-eye + Right-eye viewing. Results: Under monocular conditions, neurotypical controls exhibited an effect that patients failed to demonstrate. That is, the amplitude of the summed monocular VEPs was robustly greater than the amplitude elicited binocularly during the initial sensory processing period. In patients, this binocular effect was absent. Limitations: Patients were all medicated. Ideally, this study would also include first-episode unmedicated patients.Conclusions: These results suggest that short-term compensatory mechanisms that allow healthy individuals to generate robust VEPs in the context of monocular deprivation are not effectively activated in patients with schizophrenia. This simple assay may provide a useful biomarker of short-term plasticity in the psychotic disorders and a target endophenotype for therapeutic interventions.

  13. PATTERN ELECTRORETINOGRAPHY IN RELATION TO KINETIC AND STATIC PERIMETRY AND VISUAL ACUITY IN RETINITIS PIGMENTOSA

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    Petra Popović

    2002-12-01

    Full Text Available Background. This study was conducted to assess whether pattern ERG is a sensitive test in evaluating the retinal function in patients with retinitis pigmentosa. We wanted to determine how pattern ERG, reflecting the activity of inner retinal layers, is related to other psychophysical tests such as perimetry and visual acuity.Methods. An analysis was performed on 50 eyes of 25 patients with typical rod-cone retinitis pigmentosa. The standard Snellen visual acuity was tested. Visual field sensitivity was measured with automated static perimetry (Octopus G2 program where mean defect was taken as an index of visual field loss. In kinetic perimetry (Goldmann the average radius of the visual field measured with target II/4 and V/4 was calculated. Transient pattern ERG and all five flash ERG responses were also measured according to ISCEV standards. Amplitudes of pattern ERG P50 and N95 waves were compared to results of visual acuity and visual field testing.Results. In our group of 25 RP patients with visual acuity ranging from 0.16 to 1.0, PERG responses were preserved much better than full field ERGs. 72% of them had still recordable PERG responses, while 48% had cone and only 32% maximal responses. Scotopic rod responses were extinguished in all eyes. The normalized amplitudes of the PERG responses were also much higher (43.5% than cone (22.5% or maximal responses (4.5%. A strong correlation of both P50 and N95 amplitudes with Octopus mean defect index was found. In kinetic perimetry the correlation with PERG amplitudes was also high, but it was better with II/4 than with V/4 target. Patients with high preserved ERG responses had good visual acuity. In all patients with visual acuity less than 0.4 both flash and pattern ERG responses were already absent.Conclusions. This study shows that pattern ERG is an objective and sensitive test in evaluating the functional visual loss in retinitis pigmentosa. Amplitudes of P50 and N95 responses are linearly

  14. VISUAL ACUITY AND CLINICAL REFRACTION FOLLOWING IMPLANTATION OF VARIOUS MULTIFOCAL INTRAOCULAR LENSES

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    N. N. Temirov

    2015-01-01

    Full Text Available Aim. To analyze visual acuity, clinical refraction, and defocusing tolerance after the implantation of monofocal IOL with rotational asymmetric optic (Lentis Mplus 313 MF compared with Acrysof ReSTOR SN6AD1.Materials and methods. Phacoemulsification was performed in a total of 194 patients (288 eyes, i.e., 144 patients (188 eyes with cataract and 50 patients (100 eyes with presbyopia and high ametropia. The patients were divided into two groups. Study group included 132 patients (194 eyes implanted with Lentis Mplus while control group included 62 patients (94 eyes implanted with Acrysof ReSTOR. Uncorrected distance (5 m, intermediate (50‑70 cm, and near (20‑40 cm visual acuity under photopic (85 cd/m2 and mesopic (8 cd/m2 conditions were measured, objective and subjective refractometry were performed, and defocusing tolerance was evaluated.Results. Postoperatively, uncorrected distance and near visual acuity was high while intermediate visual acuity was moderately low. Lentis Mplus patients had better near and intermediate visual acuity under mesopic conditions as compared with Acrysof ReSTOR patients. Emmetropia (target refraction was achieved in 90.2% of study group patients and in 87.2% of control group patients. In patients implanted with Lentis Mplus, refraction was measured by subjective method. Optimal A-constant for Lentis Mplus and Acrysof ReSTOR was 118.0 and 118.6, respectively. Under defocusing, Lentis Mplus patients had better visual acuity than Acrysof ReSTOR patients. This indirectly confirms better intermediate vision.Conclusions. Lentis Mplus provides better vision at various distances that does not almost depend on light levels and induces minimal dysphotopsia. 

  15. Vestibular, Visual Acuity and Balance Outcomes in Children with Cochlear Implants: A Preliminary Report

    Science.gov (United States)

    Janky, Kristen; Givens, Diane

    2016-01-01

    There is a high incidence of vestibular loss in children with cochlear implants (CCI). However, the relationship between vestibular loss and various outcomes is unknown in children. Objectives 1) determine if age-related changes in peripheral vestibular tests occur; 2) quantify peripheral vestibular function in children with normal hearing (CNH) and CCI; 3) determine if amount of vestibular loss predicts visual acuity and balance performance. Design Eleven CCI and 12 CNH completed the following tests of vestibular function: ocular and cervical vestibular evoked myogenic potential (VEMP) to assess utricle and saccule function, and the video head impulse test (vHIT) to assess semicircular canal function. The relationship between amount of vestibular loss and the following balance and visual acuity outcomes was assessed: dynamic gait index, single leg stance, the sensory organization test, and tests of visual acuity, including dynamic visual acuity and the gaze stabilization test. Results 1) There were no significant age-related changes in peripheral vestibular testing with the exception of the n23 cervical VEMP latency, which was moderately correlated with age; 2) CCI had significantly higher rates of vestibular loss for each test of canal and otolith function; 3) Amount of vestibular loss predicted performance on single leg stance, the dynamic gait index, some conditions of the sensory organization test, and the dynamic visual acuity test. Age was also a contributing factor for predicting the performance of almost all outcomes. Conclusions Preliminarily, children with vestibular loss do not recover naturally to levels of their healthy peers, particularly with activities that utilize vestibular input; they have poorer visual acuity and balance function. PMID:26182202

  16. Change of Visual Acuity and Related Factors in Idiopathic Optic Neuritis

    Institute of Scientific and Technical Information of China (English)

    Changxian Yi; Linjie Guo; Jiexiong Ou; Hong Yan; Qiang Yu

    2001-01-01

    Purpose : To study the change of visual acuity and related factors in idiopathic optic neuritis. Methods: Retrospectively studying 136 cases (210 eyes) of idiopathic optic neuritis hospitalized in our department during last 5 years. The data was analyzed with the methods of multivariate stepwise regression analysis by SPSS statistic package. Results: The final visual acuity was very strongly related positively to the initial visual acuity at the time point of starting treatment and negatively to the time span beginning the treatment to the time showing improvement, age of patient and the duration from onset of the disorder to the time point of treatment beginning. Conclusions: Promptly right treatment can significantly change the natural course and the final vision of optic neuritis. Severe visual loss, old age, longer time without right therapy and slow improvement after the treatment may indicate an unfavorable final visual recovery. The different dosages of steroid applied in this study was not significant in view of the final visual acuity. Eye Sience 2001; 17: 46 ~ 49.

  17. Posterior staphyloma in oculocutaneous albinism: another possible cause of reduced visual acuity.

    Science.gov (United States)

    Lee, Susan; Schimmenti, Lisa A; King, Richard A; Brilliant, Murray; Anderson, Jennifer L; Schoonveld, Cheri; Summers, C Gail

    2015-12-01

    Posterior staphyloma is typically associated with myopic degeneration and has not been recognized as a cause of reduced visual acuity in albinism. We report 3 cases of posterior staphyloma, each with oculocutaneous albinism (OCA) defined by phenotype and genotype. Two cases are biological sisters with OCA type 2; one was myopic and the other was hyperopic. The third case involves a man with OCA associated with Hermansky-Pudlak syndrome (HPS-5). Staphyloma may be another cause of reduced visual acuity in albinism, particularly with increasing age. It may occur in association with myopia or hyperopia.

  18. Effects of Dilation on Electronic-ETDRS Visual Acuity in Diabetic Patients

    OpenAIRE

    Sun, Jennifer Katherine; Aiello, Lloyd Paul; Stockman, Margaret; Cavallerano, Jerry D.; Kopple, Ann; Eagan, Sharon; Qin, Haijing; Kollman, Craig; Beck, Roy W.; Glassman, Adam R.

    2009-01-01

    Objectives: To evaluate the effect of pupillary dilation on electronic-ETDRS visual acuity (EVA) in diabetic subjects and to assess post-dilation EVA as a surrogate for pre-dilation visual acuity (VA). Methods and Design: DRCR.net-protocol refraction and EVA were measured pre- and post-dilation in diabetic subjects by independent, masked examiners. Results: In 129 eyes of 66 subjects, median [25th, 75th percentiles] pre-dilation EVA score was 69 [54, 86] (Snellen-equivalent 20/40-1 [20/80-1, ...

  19. Bevacizumab Injection in Patients with Age-Related Macular Degeneration Associated with Poor Initial Visual Acuity

    OpenAIRE

    Leila El Matri; Rym Bouraoui; Ahmed Chebil; Fedra Kort; Mejda Bouladi; Rym Limaiem; Hana Landoulsi

    2012-01-01

    Purpose. To evaluate functional and anatomic effects of intravitreal bevacizumab in patients with neovascular AMD and initial low visual acuity. Methods. Retrospective case series of 38 eyes with neovascular AMD and initial visual acuity of 20/200 or less, treated with intravitreal bevacizumab injection. Results. Mean followup was 14.1 months ± 7 . 1 (range: 5 to 24 months). Mean logMAR vision at baseline was 1.38 logMAR ± 0 . 3 3 , at 6 months was 1.14 logMAR ± 0 . 3 7 ( = 0 . 0 0 1 ) and ...

  20. P2-1: Visual Short-Term Memory Lacks Sensitivity to Stereoscopic Depth Changes but is Much Sensitive to Monocular Depth Changes

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    Hae-In Kang

    2012-10-01

    Full Text Available Depth from both binocular disparity and monocular depth cues presumably is one of most salient features that would characterize a variety of visual objects in our daily life. Therefore it is plausible to expect that human vision should be good at perceiving objects' depth change arising from binocular disparities and monocular pictorial cues. However, what if the estimated depth needs to be remembered in visual short-term memory (VSTM rather than just perceived? In a series of experiments, we asked participants to remember depth of items in an array at the beginning of each trial. A set of test items followed after the memory array, and the participants were asked to report if one of the items in the test array have changed its depth from the remembered items or not. The items would differ from each other in three different depth conditions: (1 stereoscopic depth under binocular disparity manipulations, (2 monocular depth under pictorial cue manipulations, and (3 both stereoscopic and monocular depth. The accuracy of detecting depth change was substantially higher in the monocular condition than in the binocular condition, and the accuracy in the both-depth condition was moderately improved compared to the monocular condition. These results indicate that VSTM benefits more from monocular depth than stereoscopic depth, and further suggests that storage of depth information into VSTM would require both binocular and monocular information for its optimal memory performance.

  1. Patient with Macular Disease, Good Visual Acuity, and Central Visual Field Disruption and Significant Difficulties with Activities of Daily Living

    Science.gov (United States)

    Fletcher, Donald C.; Schuchard, Ronald A.; Walker, Joseph P.; Raskauskas, Paul A.

    2008-01-01

    It is generally appreciated that patients with macular disease frequently experience reduced visual acuity. It is not as widely appreciated that they often have significant central visual field disruption, which, by itself, can cause significant problems with activities of daily living, such as reading and driving, even when they maintain good…

  2. Patient with Macular Disease, Good Visual Acuity, and Central Visual Field Disruption and Significant Difficulties with Activities of Daily Living

    Science.gov (United States)

    Fletcher, Donald C.; Schuchard, Ronald A.; Walker, Joseph P.; Raskauskas, Paul A.

    2008-01-01

    It is generally appreciated that patients with macular disease frequently experience reduced visual acuity. It is not as widely appreciated that they often have significant central visual field disruption, which, by itself, can cause significant problems with activities of daily living, such as reading and driving, even when they maintain good…

  3. Effect of Target Location on Dynamic Visual Acuity During Passive Horizontal Rotation

    Science.gov (United States)

    Appelbaum, Meghan; DeDios, Yiri; Kulecz, Walter; Peters, Brian; Wood, Scott

    2010-01-01

    The vestibulo-ocular reflex (VOR) generates eye rotation to compensate for potential retinal slip in the specific plane of head movement. Dynamic visual acuity (DVA) has been utilized as a functional measure of the VOR. The purpose of this study was to examine changes in accuracy and reaction time when performing a DVA task with targets offset from the plane of rotation, e.g. offset vertically during horizontal rotation. Visual acuity was measured in 12 healthy subjects as they moved a hand-held joystick to indicate the orientation of a computer-generated Landolt C "as quickly and accurately as possible." Acuity thresholds were established with optotypes presented centrally on a wall-mounted LCD screen at 1.3 m distance, first without motion (static condition) and then while oscillating at 0.8 Hz (DVA, peak velocity 60 deg/s). The effect of target location was then measured during horizontal rotation with the optotypes randomly presented in one of nine different locations on the screen (offset up to 10 deg). The optotype size (logMar 0, 0.2 or 0.4, corresponding to Snellen range 20/20 to 20/50) and presentation duration (150, 300 and 450 ms) were counter-balanced across five trials, each utilizing horizontal rotation at 0.8 Hz. Dynamic acuity was reduced relative to static acuity in 7 of 12 subjects by one step size. During the random target trials, both accuracy and reaction time improved proportional to optotype size. Accuracy and reaction time also improved between 150 ms and 300 ms presentation durations. The main finding was that both accuracy and reaction time varied as a function of target location, with greater performance decrements when acquiring vertical targets. We conclude that dynamic visual acuity varies with target location, with acuity optimized for targets in the plane of motion. Both reaction time and accuracy are functionally relevant DVA parameters of VOR function.

  4. To Further the Near-Vision Visual Acuity Tests (2) : The Necessity of Near-Vision Visual Acuity Testing from the Results of a Detailed Examination of Children's Visual Acuity Carried Out in an Ophthalmology Clinic(Special Issue Dedicated to Professor HASHIUCHI Takeshi)

    OpenAIRE

    高橋, ひとみ; 川端, 秀仁; 衞藤, 隆

    2014-01-01

    After carrying out far-vision visual acuity tests, near-vision visual acuity tests, refraction tests, and ciliary muscle function tests at A elementary-school, we stressed the need for school medical checkups to be followed up by consultation at an ophthalmology clinic in the case of children with poor far-vision visual acuity, poor near-vision visual acuity, or eye control dysfunction. 155 children were seen in an ophthalmology clinic and given a detailed examination. We carried out an in-de...

  5. Evaluation of vestibular and dynamic visual acuity in adults with congenital deafness.

    Science.gov (United States)

    Nakajima, Yukinori; Kaga, Kimitaka; Takekoshi, Hideki; Sakuraba, Keisyoku

    2012-10-01

    This study compared vestibular and dynamic visual acuity in 19 adult athletes with deafness participating in Deaflympics to those of 25 young adults with normal hearing. Balance capability was evaluated using a one-leg standing test with eyes open and stabilometry. Caloric tests and vestibular evoked myogenic potential tests were conducted to test vestibular function. Visual function was evaluated using a dynamic visual acuity test. No significant difference was found between results of the one-leg standing test with eyes open and stabilometry with eyes open. Athletes with deafness performed better than normal hearing young adults with eyes closed. The caloric test indicated hypofunction of the lateral semicircular canal function in 5 of the 19 athletes with deafness. Balance-function tests showed normal results for both groups. The results for athletes with deafness on visual acuity were better than those of controls. Young Deaflympics athletes with deafness can adjust their balance function as well as or better than normal hearing young adults using dynamic visual acuity.

  6. Association of Visual Acuity and Cognitive Impairment in Older Individuals: Fujiwara-kyo Eye Study

    Science.gov (United States)

    Mine, Masashi; Miyata, Kimie; Morikawa, Masayuki; Nishi, Tomo; Okamoto, Nozomi; Kawasaki, Ryo; Yamashita, Hidetoshi; Kurumatani, Norio; Ogata, Nahoko

    2016-01-01

    Abstract Both visual impairment and cognitive impairment are essential factors that determine the quality of life in the aged population. The aim of this study was to determine if a correlation existed between visual acuity and cognitive impairment in an elderly Japanese population. The Fujiwara-kyo Eye Study was a cross-sectional study of individuals aged ≥68 years who lived in Nara Prefecture of Japan. Participants underwent ophthalmological examinations and cognitive function test. A mild visual impairment was defined as having a best corrected visual acuity (BCVA) >0.2 logarithm of the minimum angle of resolution (logMAR) units in the better eye. Cognitive impairment was defined as having a Mini-Mental State Examination (MMSE) score of ≤23 points. A total to 2818 individuals completed the examinations. The mean age of the participants was 76.3 ± 4.8 years (mean ± standard deviation). The mean BCVA of the better eye was −0.02 ± 0.13 logMAR units and 6.6% subjects were classified as being mildly visually impaired. The mean MMSE score was 27.3 ± 2.3 and 5.7% subjects were classified as being cognitively impaired. The proportion of subjects with cognitive or moderate visual impairment increased with age, and there was a significant correlation between the visual acuity and MMSE score (r = −0.10, p < 0.0001). Subjects with mild visual impairments had 2.4 times higher odds of having cognitive impairment than those without visual impairment (odds ratio 2.4, 95% confidence interval, 1.5–3.8, p < 0.001) after adjusting for age, sex, and length of education. We conclude that it may be important to maintain good visual acuity to reduce the risk of having cognitive impairment. PMID:27610269

  7. Association of Visual Acuity and Cognitive Impairment in Older Individuals: Fujiwara-kyo Eye Study.

    Science.gov (United States)

    Mine, Masashi; Miyata, Kimie; Morikawa, Masayuki; Nishi, Tomo; Okamoto, Nozomi; Kawasaki, Ryo; Yamashita, Hidetoshi; Kurumatani, Norio; Ogata, Nahoko

    2016-01-01

    Both visual impairment and cognitive impairment are essential factors that determine the quality of life in the aged population. The aim of this study was to determine if a correlation existed between visual acuity and cognitive impairment in an elderly Japanese population. The Fujiwara-kyo Eye Study was a cross-sectional study of individuals aged ≥68 years who lived in Nara Prefecture of Japan. Participants underwent ophthalmological examinations and cognitive function test. A mild visual impairment was defined as having a best corrected visual acuity (BCVA) >0.2 logarithm of the minimum angle of resolution (logMAR) units in the better eye. Cognitive impairment was defined as having a Mini-Mental State Examination (MMSE) score of ≤23 points. A total to 2818 individuals completed the examinations. The mean age of the participants was 76.3 ± 4.8 years (mean ± standard deviation). The mean BCVA of the better eye was -0.02 ± 0.13 logMAR units and 6.6% subjects were classified as being mildly visually impaired. The mean MMSE score was 27.3 ± 2.3 and 5.7% subjects were classified as being cognitively impaired. The proportion of subjects with cognitive or moderate visual impairment increased with age, and there was a significant correlation between the visual acuity and MMSE score (r = -0.10, p < 0.0001). Subjects with mild visual impairments had 2.4 times higher odds of having cognitive impairment than those without visual impairment (odds ratio 2.4, 95% confidence interval, 1.5-3.8, p < 0.001) after adjusting for age, sex, and length of education. We conclude that it may be important to maintain good visual acuity to reduce the risk of having cognitive impairment.

  8. Creation of an Accurate Algorithm to Detect Snellen Best Documented Visual Acuity from Ophthalmology Electronic Health Record Notes.

    Science.gov (United States)

    Mbagwu, Michael; French, Dustin D; Gill, Manjot; Mitchell, Christopher; Jackson, Kathryn; Kho, Abel; Bryar, Paul J

    2016-05-04

    Visual acuity is the primary measure used in ophthalmology to determine how well a patient can see. Visual acuity for a single eye may be recorded in multiple ways for a single patient visit (eg, Snellen vs. Jäger units vs. font print size), and be recorded for either distance or near vision. Capturing the best documented visual acuity (BDVA) of each eye in an individual patient visit is an important step for making electronic ophthalmology clinical notes useful in research. Currently, there is limited methodology for capturing BDVA in an efficient and accurate manner from electronic health record (EHR) notes. We developed an algorithm to detect BDVA for right and left eyes from defined fields within electronic ophthalmology clinical notes. We designed an algorithm to detect the BDVA from defined fields within 295,218 ophthalmology clinical notes with visual acuity data present. About 5668 unique responses were identified and an algorithm was developed to map all of the unique responses to a structured list of Snellen visual acuities. Visual acuity was captured from a total of 295,218 ophthalmology clinical notes during the study dates. The algorithm identified all visual acuities in the defined visual acuity section for each eye and returned a single BDVA for each eye. A clinician chart review of 100 random patient notes showed a 99% accuracy detecting BDVA from these records and 1% observed error. Our algorithm successfully captures best documented Snellen distance visual acuity from ophthalmology clinical notes and transforms a variety of inputs into a structured Snellen equivalent list. Our work, to the best of our knowledge, represents the first attempt at capturing visual acuity accurately from large numbers of electronic ophthalmology notes. Use of this algorithm can benefit research groups interested in assessing visual acuity for patient centered outcome. All codes used for this study are currently available, and will be made available online at https://phekb.org.

  9. Visual task performance using a monocular see-through head-mounted display (HMD) while walking.

    Science.gov (United States)

    Mustonen, Terhi; Berg, Mikko; Kaistinen, Jyrki; Kawai, Takashi; Häkkinen, Jukka

    2013-12-01

    A monocular see-through head-mounted display (HMD) allows the user to view displayed information while simultaneously interacting with the surrounding environment. This configuration lets people use HMDs while they are moving, such as while walking. However, sharing attention between the display and environment can compromise a person's performance in any ongoing task, and controlling one's gait may add further challenges. In this study, the authors investigated how the requirements of HMD-administered visual tasks altered users' performance while they were walking. Twenty-four university students completed 3 cognitive tasks (high- and low-working memory load, visual vigilance) on an HMD while seated and while simultaneously performing a paced walking task in a controlled environment. The results show that paced walking worsened performance (d', reaction time) in all HMD-administered tasks, but visual vigilance deteriorated more than memory performance. The HMD-administered tasks also worsened walking performance (speed, path overruns) in a manner that varied according to the overall demands of the task. These results suggest that people's ability to process information displayed on an HMD may worsen while they are in motion. Furthermore, the use of an HMD can critically alter a person's natural performance, such as their ability to guide and control their gait. In particular, visual tasks that involve constant monitoring of the HMD should be avoided. These findings highlight the need for careful consideration of the type and difficulty of information that can be presented through HMDs while still letting the user achieve an acceptable overall level of performance in various contexts of use. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  10. Visual acuity and retinal function in patients with Bardet-Biedl syndrome

    Directory of Open Access Journals (Sweden)

    Adriana Berezovsky

    2012-01-01

    Full Text Available OBJECTIVE: Bardet-Biedl syndrome is a genetic, multisystem disorder that causes severe visual impairment. This condition is characterized by retinal dystrophy, obesity, digit anomalies, renal disease, and hypogonadism. The purpose of this study was to analyze visual acuity and full-field electroretinogram findings in patients with the Bardet-Biedl syndrome phenotype. METHODS: The visual acuity of a group of 23 patients (15 males with ages ranging from 6-36 years (mean = 15.8±6.4; median = 14.7 was assessed. Retinal function was evaluated by full-field electroretinography, and dark-adapted thresholds were assessed. RESULTS: Visual acuity in the better-seeing eye was 20/40 or better in 5 patients (21.7%, 20/50-20/150 in 13 (56.5% patients, 20/200-20/400 in 2 (8.7% patients and worse than 20/400 in one (4.3% patient. The mean acuity in the better-seeing eye was 0.7±0.6 logMAR (20/100, Snellen equivalent. Scotopic rod and maximal responses were nondetectable in 21 (91.3% patients, and cone responses were non-detectable in 15 (65.2% patients. Elevated darkadapted visual thresholds were observed in all 19 patients who were able to be assessed, with 10 (52.6% patients having thresholds greater than 30 dB. CONCLUSIONS: In a relatively young cohort of patients with Bardet-Biedl syndrome, only 21% had 20/40 or better vision. ERG scotopic responses were absent in the majority of cases, with cone responses being observed in less than half of cases. These findings showed the early deleterious effects in retinal function and visual acuity caused by this condition.

  11. Factors affecting visual acuity after accelerated crosslinking in patients with progressive keratoconus

    Directory of Open Access Journals (Sweden)

    Ahmet Kırgız

    2016-06-01

    Full Text Available ABSTRACT Purpose: The present study aimed to report the outcomes of patients with progressive keratoconus who were treated via accelerated crosslinking (CXL 6 months earlier and to determine the factors that promoted improved visual acuity after treatment. Methods: This retrospective study included 35 eyes of 34 patients with progressive keratoconus who underwent CXL. Topographical measurements were obtained preoperatively and in the first, third, and sixth months postoperatively using a rotating Scheimpflug camera. The uncorrected visual acuity (UCVA, best-corrected visual acuity (BCVA, flat keratometry (K value (K1, steep K value (K2, average K value (avgK, topographic cylindrical value (Cyl, apical keratoscopy front (AKf, apical keratoscopy back (AKb, symmetry index front (SIf, symmetry index back (SIb, and thinnest point of the cornea (ThkMin were recorded. Results: At the 6-month follow-up, the mean UCVA and BCVA values were improved, and the K values remained stable. Statistically significant decreases in AKf (p=0.04 and the thinnest point of the cornea (p=0.001 and a statistically significant increase in AKb (p=0.01 were observed. A correlation analysis revealed that the preoperative BCVA, UCVA, K1, K2, avgK, AKf, and AKb values significantly affected visual acuity at the 6-month follow-up. Conclusions: Accelerated CXL is an effective treatment for the prevention or even reversal of keratoconus progression. The preoperative K values and apexes of the anterior and posterior cornea were found to affect visual acuity at 6 months after accelerated CXL. Both AKb steepening and AKf flattening appear to be important factors in the stabilization of keratometric values and improvement of visual outcomes.

  12. The incidence and visual acuity outcomes of children identified with ametropic amblyopia by vision screening.

    Science.gov (United States)

    Maqsud, Mohammed Aftab; Arblaster, Gemma E

    2015-04-01

    To determine the incidence of ametropic amblyopia within a vision screening program's population and report the visual acuity outcomes of children identified with the condition. The medical records of children who underwent vision screening as their first assessment at 4-5 years of age between September 1, 2005 and August 31, 2006, were retrospectively reviewed. Children referred with ≤0.30 logMAR in each eye with at least 1 year of follow-up had their hospital notes reviewed and data on final visual acuity, refractive error, and follow-up period collected. A total of 33 children identified as having ametropic amblyopia with a follow-up of at least 1 year. The incidence of ametropic amblyopia was 2%-3.2%, depending on the definition used. The mean visual acuity achieved after treatment was 0.12 logMAR, which is significantly less than the age-appropriate mean of 0.00 logMAR (P amblyopia responds to treatment, but most children demonstrate persistent reduced visual acuity at age 7 years. The incidence of ametropic amblyopia within a routine vision screening population shows that significant numbers fail to self-present. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  13. Visual acuity, contrast sensitivity, and range performance with compressed motion video

    NARCIS (Netherlands)

    Bijl, P.; Vries, S.C. de

    2010-01-01

    Video of visual acuity (VA) and contrast sensitivity (CS) test charts in a complex background was recorded using a CCD color camera mounted on a computer-controlled tripod and was fed into real-time MPEG-2 compression/decompression equipment. The test charts were based on the triangle orientation

  14. Association between alcohol consumption and diabetic retinopathy and visual acuity-the AdRem Study

    NARCIS (Netherlands)

    Lee, C. C.; Stolk, R. P.; Adler, A. I.; Patel, A.; Chalmers, J.; Neal, B.; Poulter, N.; Harrap, S.; Woodward, M.; Marre, M.; Grobbee, D. E.; Beulens, J. W.

    2010-01-01

    Aims We investigated the association between alcohol consumption and diabetic retinopathy and deterioration of visual acuity in individuals with Type 2 diabetes. Methods We conducted a cohort analysis of 1239 participants with Type 2 diabetes aged 55-81 years enrolled in the AdRem study, a sub-study

  15. Visual acuity, contrast sensitivity, and range performance with compressed motion video

    NARCIS (Netherlands)

    Bijl, P.; Vries, S.C. de

    2010-01-01

    Video of visual acuity (VA) and contrast sensitivity (CS) test charts in a complex background was recorded using a CCD color camera mounted on a computer-controlled tripod and was fed into real-time MPEG-2 compression/decompression equipment. The test charts were based on the triangle orientation di

  16. The Effects of Drift and Displacement Motion on Dynamic Visual Acuity

    Science.gov (United States)

    Aznar-Casanova, J. Antonio; Quevedo, Lluisa; Sinnett, Scott

    2005-01-01

    Dynamic Visual Acuity (DVA) can be measured from two types of equivalently considered movement referred to as drifting-motion and displacement-motion. Displacement motion can be best described as the horizontal displacement of a stimulus, thus implying pursuit eye movements, and involves moving the stimulus from the fixation point of gaze towards…

  17. Predictive factors for postoperative visual acuity in idiopathic epiretinal membrane : A systematic review

    NARCIS (Netherlands)

    Scheerlinck, Laura M E; van der Valk, Rikkert; van Leeuwen, Redmer

    2015-01-01

    The aim of this study was to review the literature on predictive factors for postoperative visual acuity (VA) in surgery for idiopathic epiretinal membrane (ERM). A systematic review of the literature in the databases of PubMed and Embase was performed. The risk of bias was assessed based on predefi

  18. The role of white light interferometry in predicting visual acuity following posterior capsulotomy.

    Science.gov (United States)

    Hanna, I T; Sigurdsson, H; Baines, P S; Roxburgh, S T

    1989-01-01

    White light interferometry was performed on 21 eyes of 19 patients presenting for posterior capsulotomy following uncomplicated extracapsular cataract surgery. The white light interferometer was able to predict post-operative visual acuity to within one Snellen line in 56 per cent of eyes and to within two Snellen lines in 76 per cent of eyes.

  19. Lawn mower injuries as a cause of serious visual acuity impairment – Case reports

    Directory of Open Access Journals (Sweden)

    Monika Jasielska

    2017-05-01

    Lawn mower induced eye injuries are a significant cause of serious visual acuity impairment or blindness. The presented study shows that lawn mower eye injuries are still a therapeutic, social and economic problem, yet are very preventable with proper eye protection and patients’ education. Current prevention strategies are inadequate, and therefore should be updated.

  20. Changes in ocular flow induced by hypo- and hypercapnia relate to static visual acuity in humans

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    Nami Someya

    2011-06-01

    Full Text Available We investigated whether the change in ocular blood flow, induced by hypo- and hypercapnia, is related to static visual acuity. Eleven healthy subjects (26±5 years underwent three treatments. A three-treatment three-period crossover design was used. In the hypocapnia treatment (HYPO, the subjects controlled their minute ventilation (VE to a target of 25 L/min for 6 min. In the hypercapnia treatment (HYPER, the subjects inspired high-fraction CO2 gas (FICO2 = 4% for 6 min. In the control treatment (CON, VE was not manipulated. We measured choroidal and retinal blood flow by laser speckle flowmetry as ocular blood flow, and static visual acuity using the Landolt C chart. End-tidal partial pressure of CO2 differed significantly among HYPO, HYPER and CON (21±1, 48±1, and 42±1 mmHg, respectively. Retinal blood flow decreased significantly from the baseline in HYPO (-22±5%, but increased significantly in HYPER (+3±9% compared to CON. Decimal visual acuity was significantly lower in HYPO than in the CON (0.21±0.1 vs. 0.24±0.1 P<0.05. These results suggest that changes in ocular blood flow induced by changes in arterial CO2 partial pressure influences visual acuity.

  1. Association between alcohol consumption and diabetic retinopathy and visual acuity-the AdRem Study

    NARCIS (Netherlands)

    Lee, C. C.; Stolk, R. P.; Adler, A. I.; Patel, A.; Chalmers, J.; Neal, B.; Poulter, N.; Harrap, S.; Woodward, M.; Marre, M.; Grobbee, D. E.; Beulens, J. W.

    2010-01-01

    Aims We investigated the association between alcohol consumption and diabetic retinopathy and deterioration of visual acuity in individuals with Type 2 diabetes. Methods We conducted a cohort analysis of 1239 participants with Type 2 diabetes aged 55-81 years enrolled in the AdRem study, a sub-study

  2. Short-term visual deprivation, tactile acuity, and haptic solid shape discrimination.

    Science.gov (United States)

    Crabtree, Charles E; Norman, J Farley

    2014-01-01

    Previous psychophysical studies have reported conflicting results concerning the effects of short-term visual deprivation upon tactile acuity. Some studies have found that 45 to 90 minutes of total light deprivation produce significant improvements in participants' tactile acuity as measured with a grating orientation discrimination task. In contrast, a single 2011 study found no such improvement while attempting to replicate these earlier findings. A primary goal of the current experiment was to resolve this discrepancy in the literature by evaluating the effects of a 90-minute period of total light deprivation upon tactile grating orientation discrimination. We also evaluated the potential effect of short-term deprivation upon haptic 3-D shape discrimination using a set of naturally-shaped solid objects. According to previous research, short-term deprivation enhances performance in a tactile 2-D shape discrimination task - perhaps a similar improvement also occurs for haptic 3-D shape discrimination. The results of the current investigation demonstrate that not only does short-term visual deprivation not enhance tactile acuity, it additionally has no effect upon haptic 3-D shape discrimination. While visual deprivation had no effect in our study, there was a significant effect of experience and learning for the grating orientation task - the participants' tactile acuity improved over time, independent of whether they had, or had not, experienced visual deprivation.

  3. PERSPECTIVE: Is acuity enough? Other considerations in clinical investigations of visual prostheses

    Science.gov (United States)

    Lepri, Bernard P.

    2009-06-01

    Visual impairing eye diseases are the major frontier facing ophthalmic research today in light of our rapidly aging population. The visual skills necessary for improving the quality of daily function and life are inextricably linked to these impairing diseases. Both research and reimbursement programs are emphasizing outcome-based results. Is improvement in visual acuity alone enough to improve the function and quality of life of visually impaired persons? This perspective summarizes the types of effectiveness endpoints for clinical investigations of visual prostheses that go beyond visual acuity. The clinical investigation of visual prostheses should include visual function, functional vision and quality of life measures. Specifically, they encompass contrast sensitivity, orientation and mobility, activities of daily living and quality of life assessments. The perspective focuses on the design of clinical trials for visual prostheses and the methods of determining effectiveness above and beyond visual acuity that will yield outcomes that are measured by improved function in the visual world and quality of life. The visually impaired population is the primary consideration in this presentation with particular emphases on retinitis pigmentosa and age-related macular degeneration. Clinical trials for visual prostheses cannot be isolated from the need for medical rehabilitation in order to obtain measurements of effectiveness that produce outcomes/evidence-based success. This approach will facilitate improvement in daily function and quality of life of patients with diseases that cause chronic vision impairment. The views and opinions are those of the author and do not necessarily reflect those of the US Food and Drug Administration, the US Department of Health and Human Services or the Public Health Service.

  4. Influence of head posture on the visual acuity of children with nystagmus

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    Ana Carla Ramos Vieira da Costa

    2014-01-01

    Full Text Available Purpose: Evaluate the relationship between the postural alignment of the head and possible interference in the view of children. Methods: We evaluated 11 children between 2 and 7 years of age of both sexes, with the visually impaired, who had nystagmus and head lock position. The test Lea Grating Acuity Test® was used to collect measurements of visual acuity. This applied on two occasions: with and without postural alignment of the head. For reliability of the postural alignment of the head, the slopes were measured by Fisiologic® software. Results: The children had a poorer performance after physiological postural alignment. This poor performance is possible due to loss of position lock nystagmus to gain postural alignment, said to be ideal. Postural compensations were observed, and sharply increased eyestrain. Conclusion: The pursuit of traditional postural alignment affect the visual response of children with visual impairments.

  5. Theoretical and applied aspects of night vision goggle resolution and visual acuity assessment

    Science.gov (United States)

    Task, H. Lee; Pinkus, Alan R.

    2007-04-01

    The image quality of night vision goggles is often expressed in terms of visual acuity, resolution or modulation transfer function. The primary reason for providing a measure of image quality is the underlying assumption that the image quality metric correlates with the level of visual performance that one could expect when using the device, for example, target detection or target recognition performance. This paper provides a theoretical analysis of the relationships between these three image quality metrics: visual acuity, resolution and modulation transfer function. Results from laboratory and field studies were used to relate these metrics to visual performance. These results can also be applied to non-image intensifier based imaging systems such as a helmet-mounted display coupled to an imaging sensor.

  6. Visual Acuity and Reaction Time in Navy Fighter Pilots,

    Science.gov (United States)

    1986-12-01

    10. SOUR CW 0FUHND"N NUmIRs Naval Medical Research & Development Command PRGKOM POX ~JCT TASK WORK UNITI IIAMET NO Ný CESSION NO.NMC, National Capital...8. Stimulus sizes were specified in minutes of visual angle ( mva ), and target exposure time was 3 seconds. 2 kdditiotwl details concerning these...This test required the subject to press the joystick iWmmeiately at the appearance of a swrathreshold spot target (2 mva 4iame-. ter). Target

  7. Dichoptic training in adults with amblyopia: Additional stereoacuity gains over monocular training.

    Science.gov (United States)

    Liu, Xiang-Yun; Zhang, Jun-Yun

    2017-08-04

    Dichoptic training is a recent focus of research on perceptual learning in adults with amblyopia, but whether and how dichoptic training is superior to traditional monocular training is unclear. Here we investigated whether dichoptic training could further boost visual acuity and stereoacuity in monocularly well-trained adult amblyopic participants. During dichoptic training the participants used the amblyopic eye to practice a contrast discrimination task, while a band-filtered noise masker was simultaneously presented in the non-amblyopic fellow eye. Dichoptic learning was indexed by the increase of maximal tolerable noise contrast for successful contrast discrimination in the amblyopic eye. The results showed that practice tripled maximal tolerable noise contrast in 13 monocularly well-trained amblyopic participants. Moreover, the training further improved stereoacuity by 27% beyond the 55% gain from previous monocular training, but unchanged visual acuity of the amblyopic eyes. Therefore our dichoptic training method may produce extra gains of stereoacuity, but not visual acuity, in adults with amblyopia after monocular training. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. A Demonstration Project on Driving with Reduced Visual Acuity and a Bioptic Telescope System in the Netherlands

    NARCIS (Netherlands)

    Melis-Dankers, Bart J.M.; Kooijman, Aart C.; Brouwer, Wiebo H.; Busscher, Rens B.; Bredewoud, Ruud A.; Derksen, Peter H.; Amersfoort, Anoeska; IJsseldijk, Martin A.M.; Delden, Geert W. van; Grotenhuis, Thea H.P.A.; Witvliet, M.D.

    2008-01-01

    Background: In Europe, driving a passenger car is prohibited if binocular best corrected visual acuity (BCVA) is below 0.5 (20/40). Some US states allow people with reduced visual acuity to use a bioptic telescope system when driving. The aim of our study is to introduce a bioptic telescope system

  9. Improving Visual Acuity of Myopes through Operant Training: The Evaluation of Psychological and Physiological Mechanisms Facilitating Acuity Enhancement

    Science.gov (United States)

    1988-12-01

    covert servo-controlled tracking optometer (Cornsweet & Crane, 1970) that made the near-instantaneous feedback of monocular accommodative state possible...and Crane infrared- optometer measures of accommodation into auditory tones that reflected the instantaneous refractive state of the eye. While an...performance change might as well have been facilitated by blur interpretation. Nonobtrusive incorporation of a covert tracking optometer (Cornsweet & Crane

  10. Adult Visual Experience Promotes Recovery of Primary Visual Cortex from Long-Term Monocular Deprivation

    Science.gov (United States)

    Fischer, Quentin S.; Aleem, Salman; Zhou, Hongyi; Pham, Tony A.

    2007-01-01

    Prolonged visual deprivation from early childhood to maturity is believed to cause permanent visual impairment. However, there have been case reports of substantial improvement of binocular vision in human adults following lifelong visual impairment or deprivation. These observations, together with recent findings of adult ocular dominance…

  11. Adult Visual Experience Promotes Recovery of Primary Visual Cortex from Long-Term Monocular Deprivation

    Science.gov (United States)

    Fischer, Quentin S.; Aleem, Salman; Zhou, Hongyi; Pham, Tony A.

    2007-01-01

    Prolonged visual deprivation from early childhood to maturity is believed to cause permanent visual impairment. However, there have been case reports of substantial improvement of binocular vision in human adults following lifelong visual impairment or deprivation. These observations, together with recent findings of adult ocular dominance…

  12. The effect of induced monocular blur on measures of stereoacuity.

    Science.gov (United States)

    Odell, Naomi V; Hatt, Sarah R; Leske, David A; Adams, Wendy E; Holmes, Jonathan M

    2009-04-01

    To determine the effect of induced monocular blur on stereoacuity measured with real depth and random dot tests. Monocular visual acuity deficits (range, 20/15 to 20/1600) were induced with 7 different Bangerter filters (depth tests and Preschool Randot (PSR) and Distance Randot (DR) random dot tests. Stereoacuity results were grouped as either "fine" (60 and 200 arcsec to nil) stereo. Across visual acuity deficits, stereoacuity was more severely degraded with random dot (PSR, DR) than with real depth (Frisby, FD2) tests. Degradation to worse-than-fine stereoacuity consistently occurred at 0.7 logMAR (20/100) or worse for Frisby, 0.1 logMAR (20/25) or worse for PSR, and 0.1 logMAR (20/25) or worse for FD2. There was no meaningful threshold for the DR because worse-than-fine stereoacuity was associated with -0.1 logMAR (20/15). Course/nil stereoacuity was consistently associated with 1.2 logMAR (20/320) or worse for Frisby, 0.8 logMAR (20/125) or worse for PSR, 1.1 logMAR (20/250) or worse for FD2, and 0.5 logMAR (20/63) or worse for DR. Stereoacuity thresholds are more easily degraded by reduced monocular visual acuity with the use of random dot tests (PSR and DR) than real depth tests (Frisby and FD2). We have defined levels of monocular visual acuity degradation associated with fine and nil stereoacuity. These findings have important implications for testing stereoacuity in clinical populations.

  13. Assessment of Visual Acuity, Refraction Changes, and Proptosis in Different Ages of Patients with Thyroid Diseases

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    J. Jankauskiene

    2012-01-01

    Full Text Available Objective. The aim of the study was to assess visual acuity, refractive status, and eye proptosis in children and young adults with Graves’ disease. Material and Methods. We have done investigations of visual acuity, refraction, and eye proptosis in 16 children, 14 teenagers, and 49 adults with Graves’ disease at Eye Clinic of Lithuanian University of Health Sciences Medical Academy. Data were compared with 14 children, 14 teenagers, and 35 adults of similar age without the same diseases (control group. Results. In the present study we observed a significant decrease of visual acuity in teenagers (0.73±0.18, P=0.001 and adults (0.7±0.16, P=0.001 with Graves’ disease. Myopia was ascertained more frequent in teenagers (42.8 percent and adults (44.9 percent with Graves’ disease. In our study exophthalmometer values were higher in children (15.94±1.98 mm, P=0.003, teenagers (17.28±2.99 mm, P=0.01, and adults (18.05±2.91 mm, P=0.001 in comparison with the controls. Conclusions. The data we have found suggest that Graves’ disease in children, teenagers, and adults has influence on vision acuity, refraction, and eye proptosis.

  14. Interferometer assessment of potential visual acuity before YAG capsulotomy: relative performance of three instruments.

    Science.gov (United States)

    Strong, N

    1992-01-01

    The accuracy of white light and laser interferometers in predicting visual acuity after YAG laser capsulotomy was compared. 42 eyes of 41 patients were tested with both a Haag-Streit (Lotmar) white light interferometer and a Rodenstock laser interferometer, and 14 were also tested with a Site white light machine. The laser interferometer predicted a final visual acuity to within one line of that actually achieved in 93%, and to within two lines in 98%, whereas for the Haag-Streit these figures were 64% and 81%, and for the Site 77% and 92%. In patients with poor initial visual acuity, the difference in the relative performance of the two instruments was increased further. When interferometry was repeated after capsulotomy, the values obtained with all instruments agreed closely with Snellen acuity. This difference in predictive accuracy shows that capsular thickening causes a greater degree of optical degradation of the image produced by a white light interferometer than occurs when a laser interferometer is employed.

  15. Comparison of the visual function index to the Snellen Visual Acuity Test in predicting older adult self-restricted driving.

    Science.gov (United States)

    Lotfipour, Shahram; Patel, Bhakti Harishchandra; Grotsky, Thomas Aaron; Anderson, Craig L; Carr, Erin M; Ahmed, Suleman Syed; Chakravarthy, Bharath; Fox, John Christian; Vaca, Federico E

    2010-10-01

    In this observational study, a modified version of the Visual Function Index (VF-14) and the Snellen Visual Acuity Test were compared in how well they correlated with self-restricted driving habits in older adults. The VF-14 was originally designed to assess vision in cataract patients; however, in this study, a modified version (mVF-14) was evaluated as a tool for predicting self-restricted driving in older drivers. During a 3-month period, 151 drivers over the age of 65 were screened at the local senior center. In addition to the Snellen Visual Acuity Test and mVF-14, each participant was given a questionnaire about their driving habits, previously used in self-restriction studies. Out of 151 total participants, 134 were included and 7 nondrivers and 10 subjects who did not complete all questionnaires were excluded. One hundred one participants exhibited normal visual acuity of 20/40 or better (75%), and 110 scored over 90 on the mVF-14 (82%). Spearman's rank sum correlation coefficient was used to analyze the data and showed significant negative correlation of the mVF-14 and Snellen with self-restricted driving. Individuals with normal vision (20/40 or better on the Snellen eye test) had both high and low mVF-14 scores. The study shows that poor vision, as indicated by the Snellen scale and low mVF-14 scores, correlates to self-imposed driving limitations. The mVF-14 showed further distinctions of self-restriction between individuals in the same Snellen Visual Acuity category. Therefore, using the mVF-14 in addition to the Snellen Visual Acuity Test can be helpful to further differentiate visual ability within older drivers who appear to have normal vision.

  16. LASER PHOTOCOAGULATION IN DIABETIC MACULAR EDEMA: EFFECTS ON VISUAL ACUITY AND MACULAR EDEMA

    Directory of Open Access Journals (Sweden)

    M.H. Dehghan

    1999-06-01

    Full Text Available Due to the importance of clinically significant macular edema in diabetic patients, this study is aimed to determine if laser photocoagulation is effective in the treatment of clinically significant diabetic macular edema. In addition, the effects of risk factors arc surveyed* This is an existing data study considering patients with clinically significant diabetic macular edema, treated with argon-green laser photocoagulation in Labbafinejad hospital, department of lasertherapy, from 1995 to 1997. in 60 (42.6% eyes the treatment method was focal, in 22 (15.6% eyes grid, and in 59 (41.84 modified grid laser photocoagulation was performed. The results are based upon deterioration of visual acuity, occurance of moderate visual loss and improvement or persistence of CSME. We studied 114 eyes from 87 patients. Two years after initial treatment, visual acuity improved in 19.1% of eyes, unchanged in 9.5% and worsened in 71.4% of eyes. After this period the rate of moderate visual loss was 28.6% and CSME was improved in 23.8% of eyes. According to our study, baseline visual acuity and retinopathy severity were two important intervening factors in response to lasertherapy. Comparing our results with natural course of diabetic macular edema, indicates that in assessing visual outcome laser photocoagulation is an effective modality in treatment of CSME, but it is not effective in maintaining or improving visual acuity, which is due to patients delay in visiting ophthalmologists and paying not enough attention to follow-up visits.

  17. Causes of suboptimal corrected visual acuity following phacoemulsification in a teaching university hospital.

    Science.gov (United States)

    Fathallah, Mohammed; Eltanamly, Rasha M; Saadeldin, Hala; Elnahry, Gehad H

    2017-03-10

    Cataract is the leading cause of reversible blindness in developing countries, with variable visual outcome following surgery. This work aims at assessing the outcomes of cataract surgery at Kasr Al Ainy Hospital and identifying the reasons for borderline and poor outcome in the studied group. A total of 150 eyes of patients with cataract and no other ocular pathology were included in this study. Uncorrected visual acuity (UCVA) and corrected visual acuity (CVA), complete ocular examination using slit-lamp, applanation tonometry, and ophthalmoscopy were performed for all patients. Biometry for intraocular lens power calculation and operative data were recorded. Patients were followed for 6 weeks; UCVA, CVA, and any complications were noted. Mean preoperative CVA was 0.16 ± 0.16 (SD) and mean postoperative CVA was 0.66 ± 0.33 (pteaching hospital where most surgeons were in their learning periods.

  18. Significant improvement in dynamic visual acuity after cataract surgery: a promising potential parameter for functional vision.

    Directory of Open Access Journals (Sweden)

    Mingxin Ao

    Full Text Available PURPOSE: Dynamic visual acuity (DVA is a relatively independent parameter for evaluating the ability to distinguish details of a moving target. The present study has been designed to discuss the extent to which age-related cataract impacts DVA in elderly individuals and to determine whether it could be restored after bilateral phacoemulsification combined with intraocular lens implantation surgery. METHODS: Twenty-six elderly cataract patients scheduled for binocular cataract surgery and 30 elderly volunteers without cataract were enrolled in the study. DVA at 15, 30, 60 and 90 degree per second (dps was assessed, and velocity-dependent visual acuity decreases between consecutive speed levels were calculated. RESULTS: Compared with the control group, the patient group exhibited significantly worse DVA performance at all speed levels (p<0.001, and the decreases in velocity-dependent visual acuity were more serious in the patient group at the intervals of 0-15 dps (p<0.001, 15-30 dps (p = 0.007 and 30-60 dps (p = 0.008. Postoperatively, DVA performance at every speed level in the patient group clearly improved (p<0.001 and recovered to levels compatible to the control group. The decrease in visual acuity with increasing speed was less pronounced than during the preoperative phase (p0-15 dps = 0.001, p15-30 dps<0.001 and p30-60 dps = 0.001 and became similar to that of the control group. The postoperative visual benefit regarding DVA was more pronounced than the improvement in static visual acuity (p15 dps = 0.001 and p<0.001 at 30 dps, 60 dps and 90 dps. CONCLUSIONS: The impact of age-related cataract on DVA was more severe than its effects on static visual acuity. After cataract surgery, not only static vision of the patients was restored markedly, but also the dynamic vision. DVA could be an important adjunct to the current evaluation system of functional vision, thereby meriting additional attention in clinical assessment.

  19. Comparison of the monocular Humphrey visual field and the binocular Humphrey esterman visual field test for driver licensing in glaucoma subjects in Sweden

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    Ayala Marcelo

    2012-08-01

    Full Text Available Abstract Background The purpose of this study was to compare the monocular Humphrey Visual Field (HVF with the binocular Humphrey Esterman Visual Field (HEVF for determining whether subjects suffering from glaucoma fulfilled the new medical requirements for possession of a Swedish driver’s license. Methods HVF SITA Fast 24–2 full threshold (monocularly and HEVF (binocularly were performed consecutively on the same day on 40 subjects with glaucomatous damage of varying degrees in both eyes. Assessment of results was constituted as either “pass” or “fail”, according to the new medical requirements put into effect September 1, 2010 by the Swedish Transport Agency. Results Forty subjects were recruited and participated in the study. Sixteen subjects passed both tests, and sixteen subjects failed both tests. Eight subjects passed the HEFV but failed the HVF. There was a significant difference between HEVF and HVF (χ2, p = 0.004. There were no subjects who passed the HVF, but failed the HEVF. Conclusions The monocular visual field test (HVF gave more specific information about the location and depth of the defects, and therefore is the overwhelming method of choice for use in diagnostics. The binocular visual field test (HEVF seems not be as efficient as the HVF in finding visual field defects in glaucoma subjects, and is therefore doubtful in evaluating visual capabilities in traffic situations.

  20. Comparison of the monocular Humphrey Visual Field and the binocular Humphrey Esterman Visual Field test for driver licensing in glaucoma subjects in Sweden.

    Science.gov (United States)

    Ayala, Marcelo

    2012-08-02

    The purpose of this study was to compare the monocular Humphrey Visual Field (HVF) with the binocular Humphrey Esterman Visual Field (HEVF) for determining whether subjects suffering from glaucoma fulfilled the new medical requirements for possession of a Swedish driver's license. HVF SITA Fast 24-2 full threshold (monocularly) and HEVF (binocularly) were performed consecutively on the same day on 40 subjects with glaucomatous damage of varying degrees in both eyes. Assessment of results was constituted as either "pass" or "fail", according to the new medical requirements put into effect September 1, 2010 by the Swedish Transport Agency. Forty subjects were recruited and participated in the study. Sixteen subjects passed both tests, and sixteen subjects failed both tests. Eight subjects passed the HEFV but failed the HVF. There was a significant difference between HEVF and HVF (χ(2), p = 0.004). There were no subjects who passed the HVF, but failed the HEVF. The monocular visual field test (HVF) gave more specific information about the location and depth of the defects, and therefore is the overwhelming method of choice for use in diagnostics. The binocular visual field test (HEVF) seems not be as efficient as the HVF in finding visual field defects in glaucoma subjects, and is therefore doubtful in evaluating visual capabilities in traffic situations.

  1. [Correctly evaluate the role of visual acuity in age-related macular degeneration treatment].

    Science.gov (United States)

    Zhang, Feng

    2012-02-01

    Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in aged population. As the aging of population, the prevalence of AMD increases gradually. Anti-VEGF medication intravitreal injection, which can obtain good therapeutic efficiency and is relatively safe, becomes the main therapy for neovascular AMD. However, high-frequency repeated treatment increases the intravitreal injections risk, as well as the costs. In clinical practice, to pursue the best-corrected visual acuity, high-frequency repeated injections are implemented and inflict psychological pressure and economic burden on patients. The author believes that to pursue the best corrected visual acuity is the ultimate aim but not the only one for every ophthalmologist and patient. The activity of lesions should be overall evaluated with fundus imaging technologies. Being people-oriented is the principle in clinical medicine. A treatment plan is made according to the patients' sickness and economy and to coordinate the relation between the best corrected visual acuity and the numbers of treatment. Based on the stabilized lesion, patient should be benefited at the lowest risk and cost with the best effect.

  2. The exact estimation of visual acuity by VEP technology: a report of 726 cases of eye injury.

    Science.gov (United States)

    Rao, Guangxun; Wu, Bingwei; Zhang, Lingli

    2010-02-01

    This study explored the accuracy of using visual evoked potentials (VEP) technology for visual acuity estimation. The enrolled 726 patients with post-traumatic unilateral decrease in visual acuity included the injured eyes served as the experimental group, and the healthy eyes as the control group. The least signal visual angle (LSVA), and amplitude and latency of P(100) were chosen as test indexes. The results under different experimental conditions were recorded by PRVEP technology. All data collected were processed and analyzed by SPSS software. The results showed that the coincidence between subjective and VEP visual acuity was 96.7% in control group, but there was very significant difference in experimental group. It was concluded that with the regression formulation for the amplitude of P(100) and vision under LSVA, visual acuity can be estimated more accurately and impartially.

  3. REPRODUCIBILITY AND COMPARISON OF VISUAL ACUITY OBTAINED WITH SIGHTBOOK MOBILE APPLICATION TO NEAR CARD AND SNELLEN CHART.

    Science.gov (United States)

    Phung, Lam; Gregori, Ninel Z; Ortiz, Angelica; Shi, Wei; Schiffman, Joyce C

    2016-05-01

    To investigate test-retest reproducibility of visual acuities obtained with a popular mobile application (app) and to explore the agreement with the standard clinic charts. Records of patients who had visual acuity measured during the same routine clinic visit with Snellen chart, Rosenbaum near vision card, and SightBook mobile app were reviewed. Acuities were converted to approximate ETDRS letters for statistical purposes. One hundred and twenty-six patients were identified. SightBook, Snellen, and near card acuities had excellent test-retest reproducibility. SightBook acuities were significantly different from the near card acuities (mean absolute difference of 5.4 and 6.1 letters in the right and left eyes) and the Snellen acuities (mean absolute difference of 7.7 and 7.9 letters in the right and left eyes). The agreement was also poor between the near card and the Snellen acuities (mean absolute difference of 6.4 and 7.6 letters in the right and left eyes). The discrepancy between SightBook mobile app and the clinic charts acuities may be large; however, the results are highly reproducible. Obtaining baseline SightBook acuity allows future vision comparisons. SightBook mobile app offers a new portable vision assessment tool for the office and remote patient monitoring.

  4. Correlation between Ocular Manifestations and Their Complications as Opposed to Visual Acuity and Treatment in Behcet's Disease

    Directory of Open Access Journals (Sweden)

    Jelena Paovic

    2013-01-01

    Full Text Available The aim of this study was to analyze ocular manifestations, their complications, and treatment in a sample of 40 patients with confirmed Behcet’s disease. Results. Serofibrinous iridocyclitis was the most common form of uveitis (60%. Retinal periphlebitis manifested in 92.5% of cases, and periphlebitis in conjunction with periarteritis was diagnosed in 72.5% of cases. Macular edema was the most frequent complication on the posterior segment (60% and it correlated with periphlebitis (P=0.45 and periphlebitis associated with periarteritis (P=0.51. Cyclosporine A and corticosteroids were used in the majority of cases (67%. Following six months of therapy, a significant improvement of visual acuity occurred in patients with initial visual acuity >0.5 on both eyes. Level of visual acuity before and after treatment had a strong significant correlation coefficient with various ocular complications. Previously proven significant increase of visual acuity in patients with macular edema depicts effectiveness of treatment in these types of ocular manifestations of Behcet’s disease. Conclusions. Significant improvement of visual acuity occurred in patients with initial visual acuity >0.5 on both eyes. The highest increase in visual acuity was achieved by laser photocoagulation in combination with triamcinolone acetonide P=0.038<0.050.

  5. Effect of aspheric multifocal toric IOL implantation on visual acuity and contrast sensitivity in patients with cataract

    Directory of Open Access Journals (Sweden)

    Ling-Ling Zhang

    2016-07-01

    Full Text Available AIM: To observe the effect of intraocular lens(IOLimplantation on visual acuity and contrast sensitivity in patients with cataract.METHODS: Fifty-eight cases(72 eyescataract patients with regular cornel astigmatism, in our hospital from May 2014 to May 2015 were randomly divided into two groups to undergo phacoemulsification and IOL implantation: the observation group: 29 cases(36 eyesreceived multifocal toric IOL implantation; the control group: 29 cases(36 eyesreceived monofocal toric IOL implantation. Uncorrected distance visual acuity(UCDVA, uncorrected near visual acuity(UCNVA, best corrected distance visual acuity(BCDVA, the best corrected near visual acuity(BCNVA, total eye astigmatism, and the dark contrast sensitivity were observed for these patients at 1 and 6mo after cataract surgery. RESULTS: There were no statistical significant difference between the two groups at postoperative 1, 6mo on UCDVA, BCNVA, BCDVA and total eye astigmatism(P>0.05. UCNVA of observation group at 1 and 6mo were better than those of control group(PPCONCLUSION: Both monofocal toric IOL implantation, and aspheric multifocal toric IOL implantation for cataract with regular corneal astigmatism are effective to improve visual acuity. But the latter treatment would contribute to the improvement of uncorrected near visual acuity and the dark contrast sensitivity.

  6. DEVELOPMENT OF RETINAL STRUCTURE AND VISUAL ACUITY IN JAPANESE FLOUNDER (PARALICHTHYS OLIVACEUS)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The retinal structure and visual acuity in Japanese flounder Paralichthys olivaceus at different stages of development were examined by light microscopy. The resolving power of the retina, the visual axis and the best visual field were estimated based on the distribution of cone cells in the retina. The visual system of the larvae appears poorly developed at hatching. The larvae with total length (TL) of less than 10 mm, have single cones only and the eyes were well pigmented. At 10-11 mm TL, most single cones fused to form double cones, with the single and double cones forming a mosaic pattern. From larvae to early juvenile the retina stretches, the cones increase in diameter and rods increase in number. Based on the highest density of the cones in the ventro-temporal region, the visual axis was orientated up-forward. The resolving power of the retina in 40-530 mm TL Japanese flounder was found to range from 25.1 to 11.5 min. The results indicated continual improvements in the visual system of the growing fish towards higher resolving power, visual acuity and sensitivity.

  7. Gains following perceptual learning are closely linked to the initial visual acuity.

    Science.gov (United States)

    Yehezkel, Oren; Sterkin, Anna; Lev, Maria; Levi, Dennis M; Polat, Uri

    2016-04-28

    The goal of the present study was to evaluate the dependence of perceptual learning gains on initial visual acuity (VA), in a large sample of subjects with a wide range of VAs. A large sample of normally sighted and presbyopic subjects (N = 119; aged 40 to 63) with a wide range of uncorrected near visual acuities (VA, -0.12 to 0.8 LogMAR), underwent perceptual learning. Training consisted of detecting briefly presented Gabor stimuli under spatial and temporal masking conditions. Consistent with previous findings, perceptual learning induced a significant improvement in near VA and reading speed under conditions of limited exposure duration. Our results show that the improvements in VA and reading speed observed following perceptual learning are closely linked to the initial VA, with only a minor fraction of the observed improvement that may be attributed to the additional sessions performed by those with the worse VA.

  8. Measurement of night vision goggle (NVG) visual acuity with the NVG resolution chart.

    Science.gov (United States)

    DeVilbiss, C A; Antonio, J C

    1994-09-01

    Night vision goggles (NVG) operations are characterized as stressful with high task loading. Any reduction in goggle or visual performance which goes undetected can have a serious effect on flight safety and operational capability. The NVG Test Lane, with its resolution chart, provides an effective cost-efficient method for aircrew members to quickly evaluate the correct positioning and focusing of their NVG's prior to each mission. This evaluation validated the ability of the NVG resolution chart to produce the same performance results as a more detailed psychophysical procedure. NVG visual acuity was measured for five subjects (four pilots and one non-pilot) with two different night vision goggles. The results supported that there is no statistical difference between the results obtained with the individual target format and the 3 x 3 format. Additionally, the pilots with current NVG experience were able to obtain a significantly better acuity level than were those without current NVG experience.

  9. Temporary marked impairment of visual acuity in a case of intraocular malignant lymphoma during radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Miyao, Yoko; Tada, Rei; Koizumi, Noriko; Yamada, Hideaki; Kinoshita, Shigeru [Kyoto Prefectural Univ. of Medicine (Japan); Ikeda, Tsunehiko

    2000-05-01

    A 56-year-old female was referred to us for blurring of both eyes since 2 years before. She had been diagnosed as chronic uveitis and responded poorly to systemic and topical corticosteroid. Her corrected visual acuity was 0.8 right and 0.5 left. Systemic studies, including magnetic resonance imaging and gadolinium scintigraphy, were negative. Vitreous biopsy led to the diagnosis of malignant lymphoma originating from the eye. Seven days after initiation of radiation at the daily doses of 2 Gy, massive subretinal infiltration developed in her right eye forming a niveau. Systemic prednisolone induced resolution of exudate with improved visual acuity to 1.0 13 days later. This cases illustrates that radiation may induce temporary aggravation of intraocular malignant lymphoma and that it may undergo resolution following systemic corticosteroid. (author)

  10. Vision-guided ocular growth in a mutant chicken model with diminished visual acuity.

    Science.gov (United States)

    Ritchey, Eric R; Zelinka, Christopher; Tang, Junhua; Liu, Jun; Code, Kimberly A; Petersen-Jones, Simon; Fischer, Andy J

    2012-09-01

    Visual experience is known to guide ocular growth. We tested the hypothesis that vision-guided ocular growth is disrupted in a model system with diminished visual acuity. We examine whether ocular elongation is influenced by form-deprivation (FD) and lens-imposed defocus in the Retinopathy, Globe Enlarged (RGE) chicken. Young RGE chicks have poor visual acuity, without significant retinal pathology, resulting from a mutation in guanine nucleotide-binding protein β3 (GNB3), also known as transducin β3 or Gβ3. The mutation in GNB3 destabilizes the protein and causes a loss of Gβ3 from photoreceptors and ON-bipolar cells (Ritchey et al., 2010). FD increased ocular elongation in RGE eyes in a manner similar to that seen in wild-type (WT) eyes. By comparison, the excessive ocular elongation that results from hyperopic defocus was increased, whereas myopic defocus failed to significantly decrease ocular elongation in RGE eyes. Brief daily periods of unrestricted vision interrupting FD prevented ocular elongation in RGE chicks in a manner similar to that seen in WT chicks. Glucagonergic amacrine cells differentially expressed the immediate early gene Egr1 in response to growth-guiding stimuli in RGE retinas, but the defocus-dependent up-regulation of Egr1 was lesser in RGE retinas compared to that of WT retinas. We conclude that high visual acuity, and the retinal signaling mediated by Gβ3, is not required for emmetropization and the excessive ocular elongation caused by FD and hyperopic defocus. However, the loss of acuity and Gβ3 from RGE retinas causes enhanced responses to hyperopic defocus and diminished responses to myopic defocus.

  11. Omega 3 fatty acids on child growth, visual acuity and neurodevelopment

    OpenAIRE

    Campoy, C.; Escolano-Margarit, MV; Anjos, T.; Szajewska, H.; Uauy, R

    2012-01-01

    The aim of this review is to evaluate the effects of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) supplementation in pregnant and lactating women and infants during postnatal life, on the visual acuity, psychomotor development, mental performance and growth of infants and children. Eighteen publications (11 sets of randomized control clinical trial [RCTs]) assessed the effects of the n-3 LCPUFA supplementation during pregnancy on neurodevelopment and growth, in the same subject...

  12. [Long-term course of visual acuity in patients with cataract surgery].

    Science.gov (United States)

    Chiseliţă, Dorin; Huţuleac, Alexandra; Cantemir, Alina; Irod, Alexandra; Obadă, Otilia; Juverdeanu, Raluca

    2012-01-01

    To compare immediate and 5 years postoperatively visual acuity (VA), after uncomplicated cataract surgery and emphasizing the main causes of visual acuity loss. This is a retrospective study that included 475 eyes that underwent uncomplicated cataract surgery between 2003-2007 by the same surgeon. 51 patients (73 eyes) returned to the last followup visit, 5 years postoperatively. Of 73 eyes, 18 eyes (24.66%) had VA 1, 5 years postoperatively. 26% (19 eyes) revealed reduced best corrected visual acuity in comparison to that from 6 weeks postoperatively Causes that led to reduced VA are: posterior capsular opacification (46.57%), age related macular degeneration (26.02%), glaucoma (10.95%), diabetic retinopathy (9.58%). Approximately a quarter of patients showed reduced VA after more than 5 years postoperatively; more than three quarters had VA > 0.5 on the last follow-up visit. The most frequent causes of reduced VA are age-related macular degeneration, glaucoma, appearence or worsening of diabetic retinopathy, posterior capsular opacification.

  13. CORRELATION OF MICROVASCULAR STRUCTURES ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY WITH VISUAL ACUITY IN RETINAL VEIN OCCLUSION.

    Science.gov (United States)

    Kang, Joon-Won; Yoo, Romi; Jo, Youn Hye; Kim, Hyung Chan

    2017-09-01

    To analyze the correlation of superficial and deep capillary plexuses using optical coherence tomography (OCT) angiography with visual acuity in eyes with retinal vein occlusion (RVO). We retrospectively reviewed the medical records of 33 patients with retinal vein occlusion (RVO; branch retinal vein occlusion in 21 patients, central retinal vein occlusion in 12 patients) and included 33 healthy subjects as a control group, who were evaluated by OCT angiography. The OCT angiography was performed on a 3 mm × 3-mm region centered on the fovea and parafoveal area. The foveal avascular zone (FAZ), and foveal and parafoveal vascular density (VD) in superficial and deep vascular plexuses were analyzed using OCT angiography. The area of superficial and deep FAZ in eyes with RVO were larger than those in fellow eyes and control eyes (P = 0.034, P = 0.018). The superficial and deep parafoveal VDs in eyes with RVO were significantly lower than those in fellow eyes and control eyes (P = 0.001, Pretinal vein occlusion (85.7%) showed a high concordance rate with respect to the location of branch retinal vein occlusion and the lowest parafoveal VD area. The multivariate analysis showed that the deep parafoveal VD was associated with best-corrected visual acuity. The OCT angiography allows to detect FAZ enlargement, increased parafoveal capillary nonperfusion, and decreased parafoveal VD in eyes with RVO. The area of superficial FAZ and the parafoveal VD are correlated with best-corrected visual acuity in eyes with RVO.

  14. Visual acuity measures do not reliably detect childhood refractive error--an epidemiological study.

    Directory of Open Access Journals (Sweden)

    Lisa O'Donoghue

    Full Text Available PURPOSE: To investigate the utility of uncorrected visual acuity measures in screening for refractive error in white school children aged 6-7-years and 12-13-years. METHODS: The Northern Ireland Childhood Errors of Refraction (NICER study used a stratified random cluster design to recruit children from schools in Northern Ireland. Detailed eye examinations included assessment of logMAR visual acuity and cycloplegic autorefraction. Spherical equivalent refractive data from the right eye were used to classify significant refractive error as myopia of at least 1DS, hyperopia as greater than +3.50DS and astigmatism as greater than 1.50DC, whether it occurred in isolation or in association with myopia or hyperopia. RESULTS: Results are presented from 661 white 12-13-year-old and 392 white 6-7-year-old school-children. Using a cut-off of uncorrected visual acuity poorer than 0.20 logMAR to detect significant refractive error gave a sensitivity of 50% and specificity of 92% in 6-7-year-olds and 73% and 93% respectively in 12-13-year-olds. In 12-13-year-old children a cut-off of poorer than 0.20 logMAR had a sensitivity of 92% and a specificity of 91% in detecting myopia and a sensitivity of 41% and a specificity of 84% in detecting hyperopia. CONCLUSIONS: Vision screening using logMAR acuity can reliably detect myopia, but not hyperopia or astigmatism in school-age children. Providers of vision screening programs should be cognisant that where detection of uncorrected hyperopic and/or astigmatic refractive error is an aspiration, current UK protocols will not effectively deliver.

  15. Contrast visual acuity after multifocal intraocular lens implantation:aspheric versus spherical design

    Directory of Open Access Journals (Sweden)

    Jun-Hua Li

    2014-02-01

    Full Text Available AIM: To evaluate contrast visual acuity (CVA after implantation of an aspheric apodized diffractive intraocular lens (IOL or a spherical apodized diffractive IOL in cataract surgery.METHOD: This prospective randomized controlled study with a 12-month follow-up compared the results of cataract surgery with implantation of an aspheric AcrySof ReSTOR SN6AD3 IOL (30 eyes and a spherical AcrySof ReSTOR SN60D3 IOL (30 eyes. CVA with best distance correction was measured at 4 contrast levels (100%, 25%, 10% and 5% under 3 levels of chart luminance [250, 85 and 25 candelas per square meter (cd/m2] using a multi-functional visual acuity tester (MFVA-100.RESULTS:At 12 months after surgery, there were no statistically significant differences in 100% CVA and 25% CVA under 250cd/m2 (P100%=0.875 and P25%=0.057 and 85cd/m2 (P100%=0.198 and P25%=0.193 between the aspheric group and the spherical group. However, the 10% CVA and 5% CVA were significant better in aspheric group than spherical group under 250cd/m2 (P10%=0.042 and P5%=0.007 and 85cd/m2 (P10%=0.002 and P5%=0.039. Under the luminance level of 25cd/m2, no significant differences was found in the 100% CVA between the 2 group (P100%=0.245, while aspheric group had better visual acuity in the remaining 3 contracts (P25%=0.023, P10%=0.026 and P5%=0.002, respectively.CONCULSION:The aspheric AcrySof ReSTOR SN6AD3 IOL provided patients with better low-contrast visual acuity than the spherical AcrySof ReSTOR SN60D3 IOL.Keyword:cataract surgery; intraocular lens; contrast sensitivity; visual acuity

  16. Osteological evidence for the evolution of activity pattern and visual acuity in primates.

    Science.gov (United States)

    Kay, R F; Kirk, E C

    2000-10-01

    Examination of orbit size and optic foramen size in living primates reveals two adaptive phenomena. First, as noted by many authors, orbit size is strongly correlated with activity pattern. Comparisons of large samples of extant primates consistently reveal that nocturnal species exhibit proportionately larger orbits than diurnal species. Furthermore, nocturnal haplorhines (Tarsius and Aotus) have considerably larger orbits than similar-sized nocturnal strepsirrhines. Orbital hypertrophy in Tarsius and Aotus accommodates the enormously enlarged eyes of these taxa. This extreme ocular hypertrophy seen in extant nocturnal haplorhines is an adaptation for both enhanced visual acuity and sensitivity in conditions of low light intensity. Second, the relative size of the optic foramen is highly correlated with the degree of retinal summation and inferred visual acuity. Diurnal haplorhines exhibit proportionately larger optic foramina, less central retinal summation, and much higher visual acuity than do all other primates. Diurnal strepsirrhines exhibit a more subtle but significant parallel enlargement of the optic foramen and a decrease in retinal summation relative to the condition seen in nocturnal primates. These twin osteological variables of orbit size and optic foramen size may be used to draw inferences regarding the activity pattern, retinal anatomy, and visual acuity of fossil primates. Our measurements demonstrate that the omomyiforms Microchoerus, Necrolemur, Shoshonius, and Tetonius, adapiform Pronycticebus, and the possible lorisiform Plesiopithecus were likely nocturnal on the basis of orbit diameter. The adapiforms Leptadapis, Adapis, and Notharctus, the phylogenetically enigmatic Rooneyia, the early anthropoids Proteopithecus, Catopithecus, and Aegyptopithecus, and early platyrrhine Dolichocebus were likely diurnal. The activity pattern of the platyrrhine Tremacebus is obscure. Plesiopithecus, Pronycticebus, Microchoerus, and Necrolemur probably had

  17. Real-time computer-based visual feedback improves visual acuity in downbeat nystagmus – a pilot study

    OpenAIRE

    Teufel, Julian; Bardins, S; Spiegel, Rainer; Kremmyda, O.; Schneider, E.; Strupp, M; Kalla, Roger

    2016-01-01

    BACKGROUND Patients with downbeat nystagmus syndrome suffer from oscillopsia, which leads to an unstable visual perception and therefore impaired visual acuity. The aim of this study was to use real-time computer-based visual feedback to compensate for the destabilizing slow phase eye movements. METHODS The patients were sitting in front of a computer screen with the head fixed on a chin rest. The eye movements were recorded by an eye tracking system (EyeSeeCam®). We tested the vi...

  18. A new visual stimulation program for improving visual acuity in children with visual impairment: a pilot study

    Directory of Open Access Journals (Sweden)

    Li-Ting eTsai

    2016-04-01

    Full Text Available The purpose of this study was to investigate the effectiveness of visual rehabilitation of a computer-based visual stimulation (VS program combining checkerboard pattern reversal (passive stimulation with oddball stimuli (attentional modulation for improving the visual acuity (VA of visually impaired (VI children and children with amblyopia and additional developmental problems. Six children (3 females, 3 males; mean age = 3.9 ± 2.3 years with impaired VA caused by deficits along the anterior and/or posterior visual pathways were recruited. Participants received eight rounds of VS training (two rounds per week of at least 8 sessions per round. Each session consisted of stimulation with 200 or 300 pattern reversals. Assessments of VA (assessed with the Lea symbol VA test or Teller VA cards, visual evoked potential (VEP, and functional vision (assessed with the Chinese-version Functional Vision Questionnaire, FVQ were carried out before and after the VS program. Significant gains in VA were found after the VS training (VA=1.05 logMAR ± 0.80 to 0.61 logMAR ± 0.53, Z=-2.20, asymptotic significance (2-tailed =0.028. No significant changes were observed in the FVQ assessment (92.8 ± 12.6 to 100.8 ± SD=15.4, Z=-1.46, asymptotic significance (2-tailed = 0.144. VEP measurement showed improvement in P100 latency and amplitude or integration of the waveform in two participants. Our results indicate that a computer-based VS program with passive checkerboard stimulation, oddball stimulus design, and interesting auditory feedback could be considered as a potential intervention option to improve the VA of a wide age range of VI children and children with impaired VA combined with other neurological disorders.

  19. A New Visual Stimulation Program for Improving Visual Acuity in Children with Visual Impairment: A Pilot Study

    Science.gov (United States)

    Tsai, Li-Ting; Hsu, Jung-Lung; Wu, Chien-Te; Chen, Chia-Ching; Su, Yu-Chin

    2016-01-01

    The purpose of this study was to investigate the effectiveness of visual rehabilitation of a computer-based visual stimulation (VS) program combining checkerboard pattern reversal (passive stimulation) with oddball stimuli (attentional modulation) for improving the visual acuity (VA) of visually impaired (VI) children and children with amblyopia and additional developmental problems. Six children (three females, three males; mean age = 3.9 ± 2.3 years) with impaired VA caused by deficits along the anterior and/or posterior visual pathways were recruited. Participants received eight rounds of VS training (two rounds per week) of at least eight sessions per round. Each session consisted of stimulation with 200 or 300 pattern reversals. Assessments of VA (assessed with the Lea symbol VA test or Teller VA cards), visual evoked potential (VEP), and functional vision (assessed with the Chinese-version Functional Vision Questionnaire, FVQ) were carried out before and after the VS program. Significant gains in VA were found after the VS training [VA = 1.05 logMAR ± 0.80 to 0.61 logMAR ± 0.53, Z = –2.20, asymptotic significance (2-tailed) = 0.028]. No significant changes were observed in the FVQ assessment [92.8 ± 12.6 to 100.8 ±SD = 15.4, Z = –1.46, asymptotic significance (2-tailed) = 0.144]. VEP measurement showed improvement in P100 latency and amplitude or integration of the waveform in two participants. Our results indicate that a computer-based VS program with passive checkerboard stimulation, oddball stimulus design, and interesting auditory feedback could be considered as a potential intervention option to improve the VA of a wide age range of VI children and children with impaired VA combined with other neurological disorders. PMID:27148014

  20. Avaliação da acuidade visual Snellen Snellen visual acuity evaluation

    Directory of Open Access Journals (Sweden)

    Marcio Zapparoli

    2009-12-01

    âncias diversas, mantém a razão de proporcionalidade dos optotipos baseada no ângulo visual e se aproxima em muito ao padrão teórico preconizado por Herman Snellen em 1862.PURPOSE: To evaluate the visual acuity (VA measurement by Snellen chart at three main Ophthalmology centers in Curitiba, compare these measurements with a computerized method for calibrating VA and also with the standard theory developed by Hermann Snellen. METHODS: Descriptive study including 15 Ophthalmology clinics and a computerized method to measure the VA. Using a tape measure and a caliper, measurement of the distance was obtained from the sitting patients' eye to VA optotypes projection on the wall. At the same time, measurement of the size of the letters of 4 lines of the VA projection on the wall was performed. RESULTS: To analyze the results, it was opted to compare the angles presented by each clinic for each measurement. It was not surprising that no clinic presented an exact angle of 5 arch minutes. Comparing clinics results with computerized method, we observed that only 2 clinics obtained better results if compared with the angles obtained from optotypes projection, but the data is very similar and with no statistical significance. In relation to the other clinics, the superiority of the computerized method is very relevant. All had differences in comparison to the gold standard. Individually, comparing computerized method to standard Snellen theory, it was observed that a condition very close to the ideal was obtained, in other words, results very similar to 5 arch minutes were noted in all the visual acuities analyzed. CONCLUSIONS: It can be concluded that there is a great heterogeneity in the evaluation of VA in different Ophthalmology centers. Also, the same patient, evaluated in different clinics, can obtain different VA measurements. The computerized method is practical, portable, adjustable for different distances, and maintains optotypes proportionality ratio based on visual angle

  1. Short-term visual deprivation does not enhance passive tactile spatial acuity.

    Directory of Open Access Journals (Sweden)

    Michael Wong

    Full Text Available An important unresolved question in sensory neuroscience is whether, and if so with what time course, tactile perception is enhanced by visual deprivation. In three experiments involving 158 normally sighted human participants, we assessed whether tactile spatial acuity improves with short-term visual deprivation over periods ranging from under 10 to over 110 minutes. We used an automated, precisely controlled two-interval forced-choice grating orientation task to assess each participant's ability to discern the orientation of square-wave gratings pressed against the stationary index finger pad of the dominant hand. A two-down one-up staircase (Experiment 1 or a Bayesian adaptive procedure (Experiments 2 and 3 was used to determine the groove width of the grating whose orientation each participant could reliably discriminate. The experiments consistently showed that tactile grating orientation discrimination does not improve with short-term visual deprivation. In fact, we found that tactile performance degraded slightly but significantly upon a brief period of visual deprivation (Experiment 1 and did not improve over periods of up to 110 minutes of deprivation (Experiments 2 and 3. The results additionally showed that grating orientation discrimination tends to improve upon repeated testing, and confirmed that women significantly outperform men on the grating orientation task. We conclude that, contrary to two recent reports but consistent with an earlier literature, passive tactile spatial acuity is not enhanced by short-term visual deprivation. Our findings have important theoretical and practical implications. On the theoretical side, the findings set limits on the time course over which neural mechanisms such as crossmodal plasticity may operate to drive sensory changes; on the practical side, the findings suggest that researchers who compare tactile acuity of blind and sighted participants should not blindfold the sighted participants.

  2. A study of static, kinetic, and dynamic visual acuity in 102 Japanese professional baseball players

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    Hoshina K

    2013-03-01

    Full Text Available Kohji Hoshina,1 Yuichi Tagami,2 Osamu Mimura,3 Hiroshi Edagawa,4 Masao Matsubara,5 Teiichi Nakayama6 1Hoshina Eye Clinic, Nishinomiya, Japan; 2Department of Ophthalmology, Kobe Century Memorial Hospital, Kobe, Japan; 3Department of Ophthalmology, Hyogo College of Medicine, Nishinomiya, Japan; 4Edagawa Eye Clinic, Tokyo, Japan; 5Department of Ophthalmology, Tokyo Women's Medical University Medical Center East, Tokyo, Japan; 6Ritsumeikan University, Kyoto, Japan Background: It seemed that visual functions might have some effects on the performance of baseball players. We measured static, kinetic, and dynamic visual acuity (SVA, KVA, and DVA, respectively of Japanese professional baseball players to ascertain whether there would be any difference in SVA, KVA, and DVA among player groups stratified according to their performance level. Methods: The subjects were 102 male professional baseball players with a mean age of 26 years who were members of a Japanese professional baseball club from 2000 to 2009. They were stratified into three groups according to their performance level: A (players who were on the roster of the top-level team all the time throughout the study period, B (players who were on the roster of the top-level team sometimes but not all the time, and C (players who were never on the roster of the top-level team. They were interviewed for the use of corrective visual aids, and examined for SVA, KVA, and DVA. The measurements of these parameters were compared among groups A, B, and C. We also investigated and analyzed the association of KVA or DVA with player position (pitchers or fielders and with hand dominance for batting. KVA was compared between the pitchers and the fielders because they each require different playing skills. DVA was compared between the right-handed and the left-handed batters. Results: There was no statistically significant difference among groups A, B, and C. There was a statistically significant difference in

  3. A double dissociation of the acuity and crowding limits to letter identification, and the promise of improved visual screening.

    Science.gov (United States)

    Song, Shuang; Levi, Dennis M; Pelli, Denis G

    2014-05-05

    Here, we systematically explore the size and spacing requirements for identifying a letter among other letters. We measure acuity for flanked and unflanked letters, centrally and peripherally, in normals and amblyopes. We find that acuity, overlap masking, and crowding each demand a minimum size or spacing for readable text. Just measuring flanked and unflanked acuity is enough for our proposed model to predict the observer's threshold size and spacing for letters at any eccentricity. We also find that amblyopia in adults retains the character of the childhood condition that caused it. Amblyopia is a developmental neural deficit that can occur as a result of either strabismus or anisometropia in childhood. Peripheral viewing during childhood due to strabismus results in amblyopia that is crowding limited, like peripheral vision. Optical blur of one eye during childhood due to anisometropia without strabismus results in amblyopia that is acuity limited, like blurred vision. Furthermore, we find that the spacing:acuity ratio of flanked and unflanked acuity can distinguish strabismic amblyopia from purely anisometropic amblyopia in nearly perfect agreement with lack of stereopsis. A scatter diagram of threshold spacing versus acuity, one point per patient, for several diagnostic groups, reveals the diagnostic power of flanked acuity testing. These results and two demonstrations indicate that the sensitivity of visual screening tests can be improved by using flankers that are more tightly spaced and letter like. Finally, in concert with Strappini, Pelli, Di Pace, and Martelli (submitted), we jointly report a double dissociation between acuity and crowding. Two clinical conditions-anisometropic amblyopia and apperceptive agnosia-each selectively impair either acuity A or the spacing:acuity ratio S/A, not both. Furthermore, when we specifically estimate crowding, we find a double dissociation between acuity and crowding. Models of human object recognition will need to

  4. The prevalence and causes of decreased visual acuity – a study based on vision screening conducted at Enukweni and Mzuzu Foundation Primary Schools, Malawi

    Directory of Open Access Journals (Sweden)

    Thom L

    2016-12-01

    Full Text Available Leaveson Thom,1 Sanchia Jogessar,1,2 Sara L McGowan,1 Fiona Lawless,1,2 1Department of Optometry, Mzuzu University, Mzuzu, Malawi; 2Brienholden Vision Institute, Durban, South Africa Aim: To determine the prevalence and causes of decreased visual acuity (VA among pupils recruited in two primary schools in Mzimba district, northern region of Malawi.Materials and methods: The study was based on the vision screening which was conducted by optometrists at Enukweni and Mzuzu Foundation Primary Schools. The measurements during the screening included unaided distance monocular VA by using Low Vision Resource Center and Snellen chart, pinhole VA on any subject with VA of less than 6/6, refraction, pupil evaluations, ocular movements, ocular health, and shadow test.Results: The prevalence of decreased VA was found to be low in school-going population (4%, n=594. Even though Enukweni Primary School had few participants than Mzuzu Foundation Primary School, it had high prevalence of decreased VA (5.8%, n=275 than Mzuzu Foundation Primary School (1.8%, n=319. The principal causes of decreased VA in this study were found to be amblyopia and uncorrected refractive errors, with myopia being the main cause than hyperopia.Conclusion: Based on the low prevalence of decreased VA due to myopia or hyperopia, it should not be concluded that refractive errors are an insignificant contributor to visual disability in Malawi. More vision screenings are required at a large scale on school-aged population to reflect the real situation on the ground. Cost-effective strategies are needed to address this easily treatable cause of vision impairment. Keywords: vision screening, refractive errors, visual acuity, Enukweni, Mzuzu foundation

  5. An assessment of the iPad as a testing platform for distance visual acuity in adults.

    Science.gov (United States)

    Black, J M; Jacobs, R J; Phillips, G; Chen, L; Tan, E; Tran, A; Thompson, B

    2013-06-20

    Visual acuity is a common measurement in general practice, and the advent of new technology such as tablet computers offers a change in the way in which these tests are delivered. The aim of this study was to assess whether measurements of distance visual acuity using LogMAR letter charts displayed on an iPad tablet computer were in agreement with standard clinical tests of visual acuity in adults with normal vision. Blinded, diagnostic test study. Single centre (University) in Auckland, New Zealand. University staff and students (n=85). Participants were required to have visual acuity better than 6/60 and wear habitual refractive correction during testing. Participants were excluded if there was any history of ocular pathology. Visual acuity measured under a number of conditions. The iPad tablet with its glossy screen was highly susceptible to glare resulting in acuity measurements that were significantly poorer (approximately 2 LogMAR lines) than those made using an ETDRS chart and a standard computerised testing system (n=56). However, fitting the iPad with an antiglare screen and positioning the device away from sources creating reflected (veiling) glare resulted in acuity measurements that were equivalent those made using gold standard charts (n=29). Tablet computers are an attractive option for visual acuity measurement due to portability, the ability to randomise letters, automated scoring of acuity and the ability to select from a range of charts. However, these devices are only suitable for use in situations where sources of glare can be eliminated.

  6. Real-time computer-based visual feedback improves visual acuity in downbeat nystagmus - a pilot study.

    Science.gov (United States)

    Teufel, Julian; Bardins, S; Spiegel, Rainer; Kremmyda, O; Schneider, E; Strupp, M; Kalla, R

    2016-01-04

    Patients with downbeat nystagmus syndrome suffer from oscillopsia, which leads to an unstable visual perception and therefore impaired visual acuity. The aim of this study was to use real-time computer-based visual feedback to compensate for the destabilizing slow phase eye movements. The patients were sitting in front of a computer screen with the head fixed on a chin rest. The eye movements were recorded by an eye tracking system (EyeSeeCam®). We tested the visual acuity with a fixed Landolt C (static) and during real-time feedback driven condition (dynamic) in gaze straight ahead and (20°) sideward gaze. In the dynamic condition, the Landolt C moved according to the slow phase eye velocity of the downbeat nystagmus. The Shapiro-Wilk test was used to test for normal distribution and one-way ANOVA for comparison. Ten patients with downbeat nystagmus were included in the study. Median age was 76 years and the median duration of symptoms was 6.3 years (SD +/- 3.1y). The mean slow phase velocity was moderate during gaze straight ahead (1.44°/s, SD +/- 1.18°/s) and increased significantly in sideward gaze (mean left 3.36°/s; right 3.58°/s). In gaze straight ahead, we found no difference between the static and feedback driven condition. In sideward gaze, visual acuity improved in five out of ten subjects during the feedback-driven condition (p = 0.043). This study provides proof of concept that non-invasive real-time computer-based visual feedback compensates for the SPV in DBN. Therefore, real-time visual feedback may be a promising aid for patients suffering from oscillopsia and impaired text reading on screen. Recent technological advances in the area of virtual reality displays might soon render this approach feasible in fully mobile settings.

  7. Reliability of Snellen charts for testing visual acuity for driving: prospective study and postal questionnaire.

    Science.gov (United States)

    Currie, Z; Bhan, A; Pepper, I

    2000-10-21

    To assess the ability of patients with binocular 6/9 or 6/12 vision on the Snellen chart (Snellen acuity) to read a number plate at 20.5 m (the required standard for driving) and to determine how health professionals advise such patients about driving. Prospective study of patients and postal questionnaire to healthcare professionals. 50 patients with 6/9 vision and 50 with 6/12 vision and 100 general practitioners, 100 optometrists or opticians, and 100 ophthalmologists. Ophthalmology outpatient clinics in Sheffield. Ability to read a number plate at 20.5 m and health professionals' advice about driving on the basis of visual acuity. 26% of patients with 6/9 vision failed the number plate test, and 34% with 6/12 vision passed it. Of the general practitioners advising patients with 6/9 vision, 76% said the patients could drive, 13% said they should not drive, and 11% were unsure. Of the general practitioners advising patients with 6/12 vision, 21% said the patients could drive, 54% said they should not drive, and 25% were unsure. The level of acuity at which optometrists, opticians, and ophthalmologists would advise drivers against driving ranged from 6/9(-2) (ability to read all except two letters on the 6/9 line of the Snellen chart) to less than 6/18. Snellen acuity is a poor predictor of an individual's ability to meet the required visual standard for driving. Patients with 6/9 vision or less should be warned that they may fail to meet this standard, but those with 6/12 vision should not be assumed to be below the standard.

  8. TrkA activation in the rat visual cortex by antirat trkA IgG prevents the effect of monocular deprivation.

    Science.gov (United States)

    Pizzorusso, T; Berardi, N; Rossi, F M; Viegi, A; Venstrom, K; Reichardt, L F; Maffei, L

    1999-01-01

    It has been recently shown that intraventricular injections of nerve growth factor (NGF) prevent the effects of monocular deprivation in the rat. We have tested the localization and the molecular nature of the NGF receptor(s) responsible for this effect by activating cortical trkA receptors in monocularly deprived rats by cortical infusion of a specific agonist of NGF on trkA, the bivalent antirat trkA IgG (RTA-IgG). TrkA protein was detected by immunoblot in the rat visual cortex during the critical period. Rats were monocularly deprived for 1 week (P21-28) and RTA-IgG or control rabbit IgG were delivered by osmotic minipumps. The effects of monocular deprivation on the ocular dominance of visual cortical neurons were assessed by extracellular single cell recordings. We found that the shift towards the ipsilateral, non-deprived eye was largely prevented by RTA-IgG. Infusion of RTA-IgG combined with antibody that blocks p75NTR (REX), slightly reduced RTA-IgG effectiveness in preventing monocular deprivation effects. These results suggest that NGF action in visual cortical plasticity is mediated by cortical TrkA receptors with p75NTR exerting a facilitatory role.

  9. Monocular inhibition reveals temporal and spatial changes in gene expression in the primary visual cortex of marmoset.

    Directory of Open Access Journals (Sweden)

    Yuki eNakagami

    2013-04-01

    Full Text Available We investigated the time course of the expression of several activity-dependent genes evoked by visual inputs in the primary visual cortex (V1 in adult marmosets. In order to examine the rapid time course of activity-dependent gene expression, marmosets were first monocularly inactivated by tetrodotoxin (TTX, kept in darkness for two days, and then exposed to various length of light stimulation. Activity-dependent genes including HTR1B, HTR2A, whose activity-dependency were previously reported by us, and well-known immediate early genes (IEGs, c-FOS, ZIF268, and ARC, were examined by in situ hybridization. Using this system, first, we demonstrated the ocular dominance type of gene expression pattern in V1 under this condition. IEGs were expressed in columnar patterns throughout layers II-VI of all the tested monocular marmosets. Second, we showed the regulation of HTR1B and HTR2A expressions by retinal spontaneous activity, because HTR1B and HTR2A mRNA expressions sustained a certain level regardless of visual stimulation and were inhibited by a blockade of the retinal activity with TTX. Third, IEGs dynamically changed its laminar distribution from half an hour to several hours upon a stimulus onset with the unique time course for each gene. The expression patterns of these genes were different in neurons of each layer as well. These results suggest that the regulation of each neuron in the primary visual cortex of marmosets is subjected to different regulation upon the change of activities from retina. It should be related to a highly differentiated laminar structure of primate visual systems, reflecting the functions of the activity-dependent gene expression in marmoset V1.

  10. Crowding is proportional to visual acuity in young and aging eyes.

    Science.gov (United States)

    Yehezkel, Oren; Sterkin, Anna; Lev, Maria; Polat, Uri

    2015-01-01

    Spatial crowding decreases object recognition and conscious visual perception in clutter. In a previous study we used brief presentation times to reveal the effects of a crowded presentation in the fovea. Here we aimed to test the relationships between varying visual acuity (VA) and crowding in the fovea, under the assumption that in uncorrected presbyopia, the processing is relatively normal, whereas the retinal input is blurred. We tested whether normal participants whose near VA is gradually reduced due to age-related deterioration (presbyopia, or "aging eye") will show an acuity-dependent increase in foveal crowding. We used brief presentations and acuity-threshold letter targets in order to magnify the crowding-effect amplitude in the fovea. A total of 195 participants with an age range of 20-68 years and an average of 44.3 ± 11.7 years (M ± SD) were divided into four age groups, all without any optical correction for the near distance. Our findings show that crowding is proportional to VA. This proportionality is affected by VA-age dependency, with a nonlinear S-shaped pattern: A steep VA reduction begins to develop, which is compatible with the normal onset age of presbyopia symptoms and a saturation in the VA-age dependency in the oldest age group, for which we propose a VA-eccentricity account. Finally, there is a high variance in the crowding amplitude in the young, even before the onset age of presbyopia symptoms, suggesting crowding conditions with limited presentation times as a highly sensitive measure of VA, which predicts visual performance in complex tasks, such as reading.

  11. The role of visual acuity and segmentation cues in compound word identification

    Directory of Open Access Journals (Sweden)

    Jukka eHyönä

    2012-06-01

    Full Text Available Studies are reviewed that demonstrate how the foveal area of the eye constrains how compound words are identified during reading. When compound words are short, their letters can be identified during a single fixation, leading to the whole-word route dominating word recognition from early on. Hence, visually marking morpheme boundaries by hyphens slows down processing by encouraging morphological decomposition when holistic processing is a feasible option. In contrast, the decomposition route dominates the early stages of identifying long compound words. Thus, visual marking of morpheme boundaries facilitates processing of long compound words, unless the initial fixation made on the word lands very close to the morpheme boundary. The reviewed pattern of results is explained by the visual acuity principle (Bertram & Hyönä, 2003 and the dual-route framework of morphological processing.

  12. The Exact Estimation of Visual Acuity by VEP Technology:A Report of 726 Cases of Eye Injury

    Institute of Scientific and Technical Information of China (English)

    饶广勋; 吴炳为; 张玲莉

    2010-01-01

    This study explored the accuracy of using visual evoked potentials(VEP)technology for visual acuity estimation.The enrolled 726 patients with post-traumatic unilateral decrease in visual acuity included the injured eyes served as the experimental group,and the healthy eyes as the control group.The least signal visual angle(LSVA),and amplitude and latency of P100 were chosen as test indexes.The results under different experimental conditions were recorded by PRVEP technology.All data collected were processed...

  13. VISUAL ACUITY AND CLINICAL REFRACTION FOLLOWING IMPLANTATION OF VARIOUS MULTIFOCAL INTRAOCULAR LENSES

    OpenAIRE

    N. N. Temirov; N. E. Temirov

    2015-01-01

    Aim. To analyze visual acuity, clinical refraction, and defocusing tolerance after the implantation of monofocal IOL with rotational asymmetric optic (Lentis Mplus 313 MF) compared with Acrysof ReSTOR SN6AD1.Materials and methods. Phacoemulsification was performed in a total of 194 patients (288 eyes), i.e., 144 patients (188 eyes) with cataract and 50 patients (100 eyes) with presbyopia and high ametropia. The patients were divided into two groups. Study group included 132 patients (194 eyes...

  14. Effect of macular photocoagulation on visual acuity of Omani patients with clinically significant macular edema

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    Zafar A Zaidi

    2009-01-01

    Full Text Available Background: The aim of this study was to determine the effect of macular laser treatment on the visual acuity (VA of Omani diabetic patients with clinically significant macular edema (CSME. Visual outcome was also correlated with duration and control of diabetes and presence or absence of hypertension and hyperlipidemia. Materials and Methods: This is a retrospective noncomparative cohort study involving 101 eyes of 72 Omani diabetic patients. Change in VA was determined using Snellen′s VA chart. The mean duration of follow-up was approximately 21 months (range, 16-24 months. Results: 29.7% of the patients maintained their vision, 35.6% showed improvement, whereas 34.7% showed a decrease in their vision. Positive visual outcome showed a statistically significant direct relationship with tight control of diabetes and absence of hypertension and an inverse relationship with the duration of diabetes. Presence of hyperlipedemia did not show a statistically significant relationship with positive visual outcome. However, it showed a trend to better visual outcome in the absence of hyperlipedemia. Peak incidence of macular edema was seen at the age of 52.3 years. Conclusion: Macular photocoagulation was found to be an effective method of treatment for CSME among Omani diabetic patients, which has resulted in a positive visual outcome in 65.3% of the patients (stable and improved vision. Effective control of diabetes, duration of diabetes, and hypertension are the factors which influence the postlaser visual outcome.

  15. Automated Measurement of Visual Acuity in Pediatric Ophthalmic Patients Using Principles of Game Design and Tablet Computers.

    Science.gov (United States)

    Aslam, Tariq M; Tahir, Humza J; Parry, Neil R A; Murray, Ian J; Kwak, Kun; Heyes, Richard; Salleh, Mahani M; Czanner, Gabriela; Ashworth, Jane

    2016-10-01

    To report on the utility of a computer tablet-based method for automated testing of visual acuity in children based on the principles of game design. We describe the testing procedure and present repeatability as well as agreement of the score with accepted visual acuity measures. Reliability and validity study. Setting: Manchester Royal Eye Hospital Pediatric Ophthalmology Outpatients Department. Total of 112 sequentially recruited patients. For each patient 1 eye was tested with the Mobile Assessment of Vision by intERactIve Computer for Children (MAVERIC-C) system, consisting of a software application running on a computer tablet, housed in a bespoke viewing chamber. The application elicited touch screen responses using a game design to encourage compliance and automatically acquire visual acuity scores of participating patients. Acuity was then assessed by an examiner with a standard chart-based near ETDRS acuity test before the MAVERIC-C assessment was repeated. Reliability of MAVERIC-C near visual acuity score and agreement of MAVERIC-C score with near ETDRS chart for visual acuity. Altogether, 106 children (95%) completed the MAVERIC-C system without assistance. The vision scores demonstrated satisfactory reliability, with test-retest VA scores having a mean difference of 0.001 (SD ±0.136) and limits of agreement of 2 SD (LOA) of ±0.267. Comparison with the near EDTRS chart showed agreement with a mean difference of -0.0879 (±0.106) with LOA of ±0.208. This study demonstrates promising utility for software using a game design to enable automated testing of acuity in children with ophthalmic disease in an objective and accurate manner. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Investigating photoreceptor densities, potential visual acuity, and cone mosaics of shallow water, temperate fish species.

    Science.gov (United States)

    Hunt, D E; Rawlinson, N J F; Thomas, G A; Cobcroft, J M

    2015-06-01

    The eye is an important sense organ for teleost species but can vary greatly depending on the adaption to the habitat, environment during ontogeny and developmental stage of the fish. The eye and retinal morphology of eight commonly caught trawl bycatch species were described: Lepidotrigla mulhalli; Lophonectes gallus; Platycephalus bassensis; Sillago flindersi; Neoplatycephalus richardsoni; Thamnaconus degeni; Parequula melbournensis; and Trachurus declivis. The cone densities ranged from 38 cones per 0.01 mm(2) for S. flindersi to 235 cones per 0.01 mm(2) for P. melbournensis. The rod densities ranged from 22800 cells per 0.01 mm(2) for L. mulhalli to 76634 cells per 0.01 mm(2) for T. declivis and potential visual acuity (based on anatomical measures) ranged from 0.08 in L. gallus to 0.31 in P. melbournensis. Higher rod densities were correlated with maximum habitat depths. Six species had the regular pattern of four double cones arranged around a single cone in the photoreceptor mosaic, while T. declivis had only rows of double cones. P. melbournensis had the greatest potential ability for detecting fine detail based on eye anatomy. The potential visual acuity estimates and rod densities can be applied to suggest the relative detection ability of different species in a commercial fishing context, since vision is a critical sense in an illuminated environment for perceiving an oncoming trawl.

  17. Microperimetric Biofeedback Training Improved Visual Acuity after Successful Macular Hole Surgery

    Directory of Open Access Journals (Sweden)

    Tomoko Ueda-Consolvo

    2015-01-01

    Full Text Available Purpose. To evaluate the efficacy of setting a preferred retinal locus relocation target (PRT and performing Macular Integrity Assessment (MAIA biofeedback training in patients showing insufficient recovery of best corrected visual acuity (BCVA despite successful closure of an idiopathic macular hole (MH. Methods. Retrospective interventional case series. Nine eyes of 9 consecutive patients with the decimal BCVA of less than 0.6 at more than 3 months after successful MH surgery were included. A PRT was chosen based on MAIA microperimetry and the patients underwent MAIA biofeedback training. BCVA, reading speed, fixation stability, and 63% bivariate contour ellipse area (BCEA were evaluated before and after the training. Statistical analysis was carried out using paired Student’s t-test. Results. PRT was chosen on the nasal side of the closed MH fovea in 8 patients. After the MAIA training, BCVA improved in all patients. The mean logMAR value of BCVA significantly improved from 0.33 to 0.12 (p=0.007. Reading speed improved in all patients (p=0.29, fixation stability improved in 5 patients (p=0.70, and 63% BCEA improved in 7 patients (p=0.21, although these improvements were not statistically significant. Conclusion. MAIA biofeedback training improved visual acuity in patients with insufficient recovery of BCVA after successful MH surgery.

  18. Night vision goggle (NVG) visual acuity under ideal conditions with various adjustment procedures.

    Science.gov (United States)

    DeVilbiss, C A; Antonio, J C; Fiedler, G M

    1994-08-01

    Night operations involve diverse mission areas and require an increased reliance on the use of night vision devices, such as night vision goggles (NVG's). Any reduction in goggle or visual performance which goes undetected can have a serious effect on flight safety and operational capability. Under controlled lighting conditions, a crewmember should be able to obtain the best possible goggle performance, and to determine if the goggle is functioning properly. These data represent a sample of 218 current USAF aircrew members representing all crew positions in both rotary and fixed-wing aircraft. Three measurements of goggle performance, expressed as NVG visual acuity, were obtained. The first measure, obtained after crewmembers adjusted the goggles with their usual adjustment methods, showed that they routinely obtain less than optimal acuity levels; i.e., averaging between 20/50 and 20/55. The second measure, taken when the NVG Resolution Chart was provided to augment their "usual" method of adjustment, showed improved performance; i.e., averaging 20/45. The third measure, taken following participation in an NVG Adjustment Procedures class, showed the greatest improvement, averaging between 20/35 and 20/40. In summary, it is reasonable to conclude that aircrew members who are able to obtain the best possible performance for their NVG's under controlled preflight conditions will obtain the best possible goggle performance under the widely varying flight conditions.

  19. TrkA activation in the rat visual cortex by antirat trkA IgG prevents the effect of monocular deprivation

    OpenAIRE

    Pizzorusso, Tommaso; Berardi, Nicoletta; Rossi, Francesco M.; Viegi, Alessandro; Venstrom, Kristine; Reichardt, Louis F.; Maffei, Lamberto

    1999-01-01

    It has been recently shown that intraventricular injections of nerve growth factor (NGF) prevent the effects of monocular deprivation in the rat. We have tested the localization and the molecular nature of the NGF receptor(s) responsible for this effect by activating cortical trkA receptors in monocularly deprived rats by cortical infusion of a specific agonist of NGF on trkA, the bivalent antirat trkA IgG (RTA-IgG). TrkA protein was detected by immunoblot in the rat visual cortex during the ...

  20. The correlation between variation of visual acuity and the anterior chamber depth in the early period after phacoemulsification

    Directory of Open Access Journals (Sweden)

    Kai-jian CHEN

    2011-04-01

    Full Text Available Objective To investigate the correlation between the visual acuity variation and the anterior chamber depth in the early period after phacoemulsification.Methods Thirty-six eyes of 32 patients with age-related cataract underwent 3.2mm clear corneal incision phacoemulsification and intraocular lens(IOL implantation.The visual acuity was examined and horizontal curvature(K1,vertical curvature(K2,corneal astigmatism,and anterior chamber depth were measured with IOL-master preoperatively and also on 1,3,7 and 15 postoperative days.The changes in parameters were compared,and the correlations among visual acuity,corneal astigmatism and anterior chamber depth were analyzed.Results Before operation and 1d,3d,7d and 15d after operation,the corneal astigmatism was-0.87±0.40D,-1.92±1.38D,-1.69±1.13D,-1.45±0.79D and-1.36±0.74D;the anterior chamber depth was 3.08±0.35mm,4.04±0.38mm,4.28±0.29mm,4.22±0.17mm and 4.22±0.16mm;the visual acuity was 0.18±0.10,0.44±0.14,0.59±0.12,0.61±0.11 and 0.62±0.14.Significant difference was found between pre-operative and postoperative visual acuity,corneal astigmatism and anterior chamber depth,and it was also found in corneal astigmatism between 1d and 15d post operation(P < 0.05,as well as in anterior chamber depth and visual acuity between 1d and 3d post operation(P < 0.05.A positive correlation was found between visual acuity and corneal astigmatism on 1d(r=0.42,P < 0.05,3d(r=0.35,P < 0.05 and 7d(r=0.35,P < 0.05 post operation;and a negative correlation was found between visual acuity and anterior chamber depth on 3d(r=-0.29,P < 0.05,7d(r=-0.43,P < 0.01 and 15d(r=-0.37,P < 0.05 post operation.Conclusion Both the corneal astigmatism and the anterior chamber depth are correlated with the visual acuity variation in the early period after phacoemulsification.

  1. Comparison on testability of visual acuity, stereo acuity and colour vision tests between children with learning disabilities and children without learning disabilities in government primary schools

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    Nurul Farhana Abu Bakar

    2014-01-01

    Full Text Available Context: Children with learning disabilities might have difficulties to communicate effectively and give reliable responses as required in various visual function testing procedures. Aims: The purpose of this study was to compare the testability of visual acuity using the modified Early Treatment Diabetic Retinopathy Study (ETDRS and Cambridge Crowding Cards, stereo acuity using Lang Stereo test II and Butterfly stereo tests and colour perception using Colour Vision Test Made Easy (CVTME and Ishihara′s Test for Colour Deficiency (Ishihara Test between children in mainstream classes and children with learning disabilities in special education classes in government primary schools. Materials and Methods: A total of 100 primary school children (50 children from mainstream classes and 50 children from special education classes matched in age were recruited in this cross-sectional comparative study. The testability was determined by the percentage of children who were able to give reliable respond as required by the respective tests. ′Unable to test′ was defined as inappropriate response or uncooperative despite best efforts of the screener. Results: The testability of the modified ETDRS, Butterfly stereo test and Ishihara test for respective visual function tests were found lower among children in special education classes ( P < 0.001 but not in Cambridge Crowding Cards, Lang Stereo test II and CVTME. Conclusion: Non verbal or "matching" approaches were found to be more superior in testing visual functions in children with learning disabilities. Modifications of vision testing procedures are essential for children with learning disabilities.

  2. Effect of myopic defocus on static visual acuity and dynamic visual acuity%近视性离焦对静态视力和动态视力的影响

    Institute of Scientific and Technical Information of China (English)

    邓军; 保金华; 陈浩

    2011-01-01

    Background Researches have suggested that the defocus can induce the change of static visual acuity,but whether it produce influence on dynamic visual acuity is not clear.Objective This study was to investigate the impact of myopic defocus on static visual acuity and dynamic visual acuity and explore the essential difierence between static visual acuity and dynamic visual acuity. Methods Forty volunteers were enrolled in this trial.including 20 adults with the age of 27.4±1.64 years and 20 children with the age of 11.70+1.49 years.All the eyes of subjects received regular examined to excluded the eye disease with the best corrected vision of ≥1.0 D,astigmatism of ≤0.75 D and anisometropia <1.50 D.+1.00 D,+1.50 D,+2.00 D,+2.50 D slasses were ware respectively for the defocus on the foundation of full correction.Dynamic visual acuity was inspected by using selfmade DVA-I training software.and static visual acuity wag tested by static visual acuity chart (Precision Vision,CAT.NO.2125).This clinical trial complied with the Helsinki Declaration and obtained the approval of Ethic Committee of Wenzhou Medical College.Written informed consent was received from each individual prior to the protocol. Results The dynamic and static visual acuities were gradually decreased with the elevation of defocus (F=506.907,P=0.000).No significant differences were found between static visual acuity and dynamic visual acuity in adult or children at various defocus(P>0.05).The regression linear analysis showed that a positive correlation between static visual acuity with defoeus(R2=0.819,t=26.72,P=0.000) or dynamic visual acuity with defoeus(R2=0.826,t=27.42,P=0.000).The slope and intercept between defocus with static visual acuity were steeper than that between defocus and dynamic visual acuity (slope:F=34.18,P=0.000;intercept:F=1005.56,P=0.001). Conclusion The effect of defocus on static visual acuity is different from that of dynamic visual acuity.It could be speculated that

  3. "A retrospective cohort study for prognostic significance of visual acuity for near over that for distance in anisometropic amblyopia.".

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    Singh Vinita

    1992-01-01

    Full Text Available A cohort of 50 anisometropic amblyopes, between the ages of 2.5 to 10 years, was studied retrospectively to assess the prognostic significance of visual acuity for near over that for distance. There is ample evidence in the literature for a significantly lower accommodative response in the anisometropic amblyopic eye. It has been proposed that the efferent accommodative dysfunction may be a fundamental and causative factor in anisometropic amblyopia. A reduced visual acuity for near over that for distance was found in 17 [34%] patients and in 11 out of these the near vision improved after an addition of +3.0D sph. When a reduced visual acuity for near, was obtained it was difficult to determine whether the visual afferent system (due to insufficient visual input, or the accommodation efferent mechanism was responsible. However an improvement in corrected near vision by addition of +3.0D sph. suggested an accommodative dysfunction. In patients with reduced visual acuity for near over that for distance, not only was the final visual outcome poor but also the onset of visual improvement in response to amblyopia therapy was delayed.

  4. Metabolic Changes in the Bilateral Visual Cortex of the Monocular Blind Macaque: A Multi-Voxel Proton Magnetic Resonance Spectroscopy Study.

    Science.gov (United States)

    Wu, Lingjie; Tang, Zuohua; Feng, Xiaoyuan; Sun, Xinghuai; Qian, Wen; Wang, Jie; Jin, Lixin; Jiang, Jingxuan; Zhong, Yufeng

    2017-02-01

    The metabolic changes accompanied with adaptive plasticity in the visual cortex after early monocular visual loss were unclear. In this study, we detected the metabolic changes in bilateral visual cortex of normal (group A) and monocular blind macaque (group B) for studying the adaptive plasticity using multi-voxel proton magnetic resonance spectroscopy ((1)H-MRS) at 32 months after right optic nerve transection. Then, we compared the N-Acetyl aspartate (NAA)/Creatine (Cr), myoinositol (Ins)/Cr, choline (Cho)/Cr and Glx (Glutamate + glutamine)/Cr ratios in the visual cortex between two groups, as well as between the left and right visual cortex of group A and B. Compared with group A, in the bilateral visual cortex, a decreased NAA/Cr and Glx/Cr ratios in group B were found, which was more clearly in the right visual cortex; whereas the Ins/Cr and Cho/Cr ratios of group B were increased. All of these findings were further confirmed by immunohistochemical staining. In conclusion, the difference of metabolic ratios can be detected by multi-voxel (1)H-MRS in the visual cortex between groups A and B, which was valuable for investigating the adaptive plasticity of monocular blind macaque.

  5. Optimización de la agudeza visual en las FAS Optimization of visual acuity in Spanish Armed Forces

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    J. Medin Catoira

    2011-06-01

    Full Text Available Introducción: La existencia de una agudeza visual óptima es requerida para la mayor parte de las actividades del personal de las FAS, pero se hace estrictamente necesaria en el despliegue dentro del teatro de operaciones internacional. Material y Método: Hemos realizado un estudio sobre el registro de la agudeza visual en un grupo aleatorio (n = 54 durante los reconocimientos periódicos de permanencia realizados en nuestro centro. Resultados: Sólo 3 casos (5,56% reconocen ver mal; 20 (37,04% han utilizado corrección en algún momento de su vida; 12 (22,22% utilizan corrección; en 32 (60,38% sería altamente recomendable el uso de corrección. Ningún caso (0% de los usuarios de corrección posee corrección de repuesto (en gafas. Conclusión: Se hace incidencia en el control y registro de los parámetros visuales en el personal de las FAS, especialmente en actividades de riesgo y despliegue internacional.Introduction: The existence of an optimal visual acuity is required for most of the activities of the membrers of the Armed Forces, but it is strictly necessary in the deployment within the international theater. Materials and Methods: We conducted a study of visual acuity in a random group of periodical surveys in our center. Results: Only 3 cases (5.56% recognize look bad; 20 (37.04% have used correction at some point in their lives; 12 (22.22% used correction; in 32 cases (60.38% was highly recommended the use of correction. No cases (0% of users of correction has a duplicate of it (in glasses. Conclusions: The study suggests the need for better surveillance and control of visual parameters of the Armed Forces members, especially in risky activities and international deployment.

  6. A Standardized Procedure and Normative Values for Measuring Binocular Dynamic Visual Acuity

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    Amanda Miskewicz-Zastrow, OD

    2015-04-01

    Full Text Available Background: Binocular dynamic visual acuity (BDVA is the ability to differentiate fine details in a moving object such as seams on a pitched baseball or the rotation of a tennis ball, both of which can travel up to speeds exceeding 100 miles per hour. BDVA is one of many binocular visual measurements to examine binocular function. This study was designed to provide a standardized procedure for measuring BDVA and normal values for a sample population. Previous studies have used different techniques for measurement, and thus have no normative data for comparison. Methods: The BCVA attachment to the Bernell Rotation Trainer was used to measure BDVA in 22 subjects (10 females and 12 males between the ages of 23 and 30. Only subjects with a refractive error between +1.00 D and -7.00 D (spherical equivalent and with best corrected visual acuity of 20/20 or better were able to participate in the study. BDVA was recorded at three different rotation speeds (29 RPM, 24 RPM, and 16 RPM. At each RPM, accuracy and the time to completion of all nine lines were measured. The subjects were also asked to complete a questionnaire designed to evaluate factors that may influence the BDVA results. Results: A decrease in RPM resulted in a corresponding decrease in the subject’s completion time and an increase in accuracy. The same trend was seen when comparing males and females; however, the females’ accuracy was lower and the time was greater when compared to the males, but these were not statistically significant. Conclusions: This was the first study designed to use the Bernell Rotation Trainer to quantitatively measure BDVA in a standardized way. Our results showed similar trends in both males and females. In addition, this study provides a strong foundation for future research, such as comparing BDVA of athletes and non-athletes, or comparing athletes with different skill levels, or comparing athletes who participate in different sports.

  7. The Effect of a Monocular Helmet-Mounted Display on Aircrew Health: A Cohort Study of Apache AH Mk 1 Pilots Four-Year Review

    Science.gov (United States)

    2009-12-01

    conventional Snellen charts (Bailey and Lovie, 1976). This test was conducted monocularly for both left and right eyes using the habitual correction...from logMAR to Snellen acuity (20/xx) is accomplished using the formula to determine the Snellen denominator: xx = 20 x 10 logMAR. For the...last measurement cycle, values were available for all 23 control subjects. For the right eye, the mean visual acuity was 0.08 logMAR ( Snellen

  8. Refraction and visual acuity in a national Danish cohort of 4-year-old children of extremely preterm delivery.

    Science.gov (United States)

    Fledelius, Hans C; Bangsgaard, Regitze; Slidsborg, Carina; laCour, Morten

    2015-06-01

    A recent threefold increase in laser treatment for advanced retinopathy of prematurity (ROP) triggered a nationwide preschool ophthalmic and developmental status among extremely preterm survivors. Here, we discuss refraction and visual acuity. Survivors (n = 178) from a national birth cohort (February 2004 to March 2006) of gestational age refraction and keratometry were achieved by Retinomax autokeratorefractor and visual acuities by symbol recognition (HOTV, logMAR). The refractive distribution presented a myopic tail (4.5%) and a hyperopic tail (11.9% ≥+2.5 D) as special preterm features, and corneas were more curved. Astigmatism and anisometropia were only marginally increased, and visual acuities were generally good. Best-corrected binocular median logMAR visual acuity was 0.1 in FT and 0.2 in PT, in Snellen equivalents 0.8 and 0.63. Snellen acuity ≤0.5 occurred across the ROP subgroups, but mainly in those with at least ROP stage 3. Two children had low vision. The overall fair outcome for refraction and function is in accordance with other recent northern Europe experience. The results differ in particular from the poorer ophthalmic outcomes reported in the pioneer US treatment studies (cryotherapy for ROP and ETROP). The diode laser ablations (n = 32) appeared effective in our series; except one child, all treated subjects had good or fair social vision at the age of 4 years. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  9. Comparison of distance and near visual acuity in patients with vision loss due to cataract.

    Science.gov (United States)

    Mercado, Carmel L; Doroslovački, Pavle; Wang, Jiangxia; Siddiqui, Aazim A; Kolker, Andrew F; Kolker, Richard J

    2017-02-01

    The purpose of this study was to assess whether there is a disparity in distance and near best-corrected visual acuity (BCVA) in cataract eyes. 102 patients with cataract (N = 121 eyes) were seen in clinic between January and November 2013 at the Wilmer Eye Institute Comprehensive Eye Service. An age-related macular degeneration (ARMD) group (N = 27 eyes) was also identified for comparison. Distance and near BCVA were measured as part of the standard ophthalmic evaluation. Snellen measurements were converted to their LogMAR equivalents for statistical analysis. Near was better than distance BCVA with mean difference of 1.38 lines (P distance BCVA disparity is a statistically significant finding seen with cataracts. This may have further implications in patients with both cataract and ARMD as the presence of disparity may suggest a cataract etiology playing a greater role in vision loss. This comparison may be useful for surgical prognostication and as a quick triage tool in conjunction with, or in place of, a potential acuity meter and dilated near-pinhole test.

  10. Individual Differences in Scotopic Visual Acuity and Contrast Sensitivity: Genetic and Non-Genetic Influences.

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    Alex J Bartholomew

    Full Text Available Despite the large amount of variation found in the night (scotopic vision capabilities of healthy volunteers, little effort has been made to characterize this variation and factors, genetic and non-genetic, that influence it. In the largest population of healthy observers measured for scotopic visual acuity (VA and contrast sensitivity (CS to date, we quantified the effect of a range of variables on visual performance. We found that young volunteers with excellent photopic vision exhibit great variation in their scotopic VA and CS, and this variation is reliable from one testing session to the next. We additionally identified that factors such as Circadian preference, iris color, astigmatism, depression, sex and education have no significant impact on scotopic visual function. We confirmed previous work showing that the amount of time spent on the vision test influences performance and that laser eye surgery results in worse scotopic vision. We also showed a significant effect of intelligence and photopic visual performance on scotopic VA and CS, but all of these variables collectively explain <30% of the variation in scotopic vision. The wide variation seen in young healthy volunteers with excellent photopic vision, the high test-retest agreement, and the vast majority of the variation in scotopic vision remaining unexplained by obvious non-genetic factors suggests a strong genetic component. Our preliminary genome-wide association study (GWAS of 106 participants ruled out any common genetic variants of very large effect and paves the way for future, larger genetic studies of scotopic vision.

  11. [Laser pointers are not toys; eye injury with permanent loss of visual acuity].

    Science.gov (United States)

    Keunen, Jan E E; Delbecq, Ann-Laure M H; Cruysberg, J R M Hans; van Meurs, Jan C; Gan, Ivan M; Berendschot, Tos T J M

    2014-01-01

    In the nineteen-nineties, there was much hype in the European media about presumed laser pointer maculopathy. However, the recent introduction of more powerful and therefore more dangerous laser pointers and their easy availability on the internet necessitates vigilance on the issue. This is an urgent matter, as here we report three cases of proven maculopathy due to an unsafe laser pointer. Three boys aged 13, 9 and 12 years used an unsafe laser pointer as a toy and looked repeatedly into the pointer, resulting in a permanent reduction in visual acuity due to macular damage. Laser pointers are not designed to be children's toys or instruments to annoy people in a crowd. Health authorities and the ophthalmic community should be aware of the potential danger of improper use of high-output laser pointers and warn the general public before the widespread availability of unsafe laser pointers and consequently laser pointer-induced macular damage becomes a true social problem.

  12. Visual Acuity Changes during Pregnancy and Postpartum: A Cross-Sectional Study in Iran

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    Khashayar Mehdizadehkashi

    2014-01-01

    Full Text Available In this research, we represent the changes in visual acuity during pregnancy and after delivery. Changes as myopic shift start during second trimester and will be stopped after delivery; however it is obtained that women will have the same refractive error as what they had in the first trimester, after postpartum. So, any change in their spectacle prescription during this period is forbidden. As a result, not only changing in hormones can cause myopic shift in vision, but also overweight has its retributive role. What we are trying to do is to notify gynecologists and optometrists to be aware of these changes, so as to leave spectacle prescription writing to the session after postpartum period.

  13. Visual acuity and refraction by age for children of three different ethnic groups in Paraguay

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    Marissa Janine Carter

    2013-04-01

    Full Text Available PURPOSE: To characterize refractive errors in Paraguayan children aged 5-16 years and investigate effect of age, gender, and ethnicity. METHODS:The study was conducted at 3 schools that catered to Mennonite, indigenous, and mixed race children. Children were examined for presenting visual acuity, autorefraction with and without cycloplegia, and retinoscopy. Data were analyzed for myopia and hyperopia (SE ≤-1 D or -0.5 D and ≥2 D or ≥3 D and astigmatism (cylinder ≥1 D. Spherical equivalent (SE values were calculated from right eye cycloplegic autorefraction data and analyzed using general linear modelling. RESULTS: There were 190, 118, and 168 children of Mennonite, indigenous and mixed race ethnicity, respectively. SE values between right/left eyes were nonsignificant. Mean visual acuity (VA without correction was better for Mennonites compared to indigenous or mixed race children (right eyes: 0.031, 0.090, and 0.102 logMAR units, respectively; P<0.000001. There were 2 cases of myopia in the Mennonite group (1.2% and 2 cases in the mixed race group (1.4% (SE ≤-0.5 D. The prevalence of hyperopia (SE ≥2 D was 40.6%, 34.2%, and 46.3% for Mennonite, indigenous and mixed race children. Corresponding astigmatism rates were 3.2%, 9.5%, and 12.7%. Females were slightly more hyperopic than males, and the 9-11 years age group was the most hyperopic. Mennonite and mixed race children were more hyperopic than indigenous children. CONCLUSIONS: Paraguayan children were remarkably hyperopic and relatively free of myopia. Differences with regard to gender, age, and ethnicity were small.

  14. Cataract Surgery and Visual Acuity in Elderly Japanese: Results of Fujiwara-kyo Eye Study

    Science.gov (United States)

    Miyata, Kimie; Yoshikawa, Tadanobu; Mine, Masashi; Nishi, Tomo; Okamoto, Nozomi; Ueda, Tetsuo; Kawasaki, Ryo; Kurumatani, Norio; Ogata, Nahoko

    2017-01-01

    Abstract The aim of this study was to determine the presence of prior cataract surgery and best-corrected visual acuity (BCVA) in an elderly Japanese cohort. The Fujiwara-kyo Eye Study was a prospective, population-based, cross-sectional epidemiological study. The subjects were ≥68 years who lived in the Nara Prefecture and responded to recruitment notices. All of the subjects underwent comprehensive ophthalmological examinations, and the sociodemographic information and medical history, including prior cataract surgery, were obtained by answers to a questionnaire. The associations between the BCVA, age, sex, and history of cataract surgery were determined. A total of 2,873 subjects whose mean age was 76.3 ± 4.9 (mean ± standard deviation) years were studied. The mean BCVA was −0.020 ± 0.14 logarithm of the minimum angle of resolution units, and it was significantly better in the group with education ≥13 years (p < 0.01). Overall, 24.2% of the subjects had undergone cataract surgery, and 41.7% of the subjects ≥80 years had undergone cataract surgery. The incidence of prior cataract surgery increased with increasing age (p < 0.001 for trend). The mean BCVA of eyes with cataract surgery was significantly better than that of eyes without cataract surgery in subjects ≥80 years (p < 0.01). Visual acuity was generally good in this cohort of elderly Japanese subjects. In this cohort, 24.2% of the subjects had undergone cataract surgery, and the subjects ≥80 years had better BCVA than those without cataract surgery. PMID:28451472

  15. mRNAs coding for neurotransmitter receptors and voltage-gated sodium channels in the adult rabbit visual cortex after monocular deafferentiation

    Science.gov (United States)

    Nguyen, Quoc-Thang; Matute, Carlos; Miledi, Ricardo

    1998-01-01

    It has been postulated that, in the adult visual cortex, visual inputs modulate levels of mRNAs coding for neurotransmitter receptors in an activity-dependent manner. To investigate this possibility, we performed a monocular enucleation in adult rabbits and, 15 days later, collected their left and right visual cortices. Levels of mRNAs coding for voltage-activated sodium channels, and for receptors for kainate/α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), N-methyl-d-aspartate (NMDA), γ-aminobutyric acid (GABA), and glycine were semiquantitatively estimated in the visual cortices ipsilateral and contralateral to the lesion by the Xenopus oocyte/voltage-clamp expression system. This technique also allowed us to study some of the pharmacological and physiological properties of the channels and receptors expressed in the oocytes. In cells injected with mRNA from left or right cortices of monocularly enucleated and control animals, the amplitudes of currents elicited by kainate or AMPA, which reflect the abundance of mRNAs coding for kainate and AMPA receptors, were similar. There was no difference in the sensitivity to kainate and in the voltage dependence of the kainate response. Responses mediated by NMDA, GABA, and glycine were unaffected by monocular enucleation. Sodium channel peak currents, activation, steady-state inactivation, and sensitivity to tetrodotoxin also remained unchanged after the enucleation. Our data show that mRNAs for major neurotransmitter receptors and ion channels in the adult rabbit visual cortex are not obviously modified by monocular deafferentiation. Thus, our results do not support the idea of a widespread dynamic modulation of mRNAs coding for receptors and ion channels by visual activity in the rabbit visual system. PMID:9501250

  16. Test–retest reliability of contrast visual acuities in a clinical population

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    Anusha Y. Sukha

    2017-01-01

    Full Text Available Background: Previously, contrast visual acuities (VA have been evaluated as a potential screening, diagnostic and predictive tool in cases where standard visual acuity remains intact. Issues around contrast acuity sometimes make it difficult for clinicians to make appropriate clinical decisions and thus such tests have to be standardised and reliable.Aim: To investigate test–retest reliability of contrast VA in healthy adults in a clinical setting.Methods: Best compensated contrast VA at 100%, 10%, 5% and 2.5% of 155 patients (mean age 39.7 ± 12.2 years were measured using the computerised Thomson Test Chart 2000 Expert. For all participants and at each contrast level, two measurements per right eye were determined. Test–retest reliability for the four contrast levels were assessed using reliability coefficients and Bland–Altman plots. Participants were also divided into three age groups of young (18–39 years, n = 72, middle-age (40–49 years, n = 45 and elderly (50–67 years, n = 38 and reliability was assessed within and between age and gender groups.Results: For the whole-sample test and retest, measurements within each contrast level were not statistically different (p ≥ 0.05. Thus, test and retest measurements per participant were averaged and whole-sample mean-contrast VA and standard deviations for 100%, 10%, 5% and 2.5% were -0.146 ± 0.060, 0.050 ± 0.071, 0.135 ± 0.079 and 0.405 ± 0.115 logMAR, respectively. Significant differences were found between all pairs of contrast levels compared (p ≤ 0.0125. Mean-contrast VA within each age group were also significantly different across all contrast levels (p < 0.0001. Mean-contrast VA at each contrast level between the age groups indicated that mean-contrast VA were not significantly different between the young and middle-age groups (p > 0.05 but were statistically different between the young and elderly groups (p < 0.01. Only mean-contrast VA 10% was significantly different

  17. Effects of brief daily periods of unrestricted vision during early monocular form deprivation on development of visual area 2.

    Science.gov (United States)

    Zhang, Bin; Tao, Xiaofeng; Wensveen, Janice M; Harwerth, Ronald S; Smith, Earl L; Chino, Yuzo M

    2011-09-14

    Providing brief daily periods of unrestricted vision during early monocular form deprivation reduces the depth of amblyopia. To gain insights into the neural basis of the beneficial effects of this treatment, the binocular and monocular response properties of neurons were quantitatively analyzed in visual area 2 (V2) of form-deprived macaque monkeys. Beginning at 3 weeks of age, infant monkeys were deprived of clear vision in one eye for 12 hours every day until 21 weeks of age. They received daily periods of unrestricted vision for 0, 1, 2, or 4 hours during the form-deprivation period. After behavioral testing to measure the depth of the resulting amblyopia, microelectrode-recording experiments were conducted in V2. The ocular dominance imbalance away from the affected eye was reduced in the experimental monkeys and was generally proportional to the reduction in the depth of amblyopia in individual monkeys. There were no interocular differences in the spatial properties of V2 neurons in any subject group. However, the binocular disparity sensitivity of V2 neurons was significantly higher and binocular suppression was lower in monkeys that had unrestricted vision. The decrease in ocular dominance imbalance in V2 was the neuronal change most closely associated with the observed reduction in the depth of amblyopia. The results suggest that the degree to which extrastriate neurons can maintain functional connections with the deprived eye (i.e., reducing undersampling for the affected eye) is the most significant factor associated with the beneficial effects of brief periods of unrestricted vision.

  18. Bifocals in children with Down syndrome (BiDS) - visual acuity, accommodation and early literacy skills.

    Science.gov (United States)

    Nandakumar, Krithika; Leat, Susan J

    2010-09-01

    Reduced accommodation is seen in children and young adults with Down syndrome (DS), yet providing bifocals has not become a routine clinical management. This study investigates the impact of bifocals on visual function, visual perceptual and early literacy skills in a group of school children with DS.   In this longitudinal study, each child was followed for 5months with single-vision (SV) lenses after which bifocals were prescribed if required, based on their accommodative response. Visual acuity (VA), accommodation, perceptual and literacy skills were measured after adaptation to bifocals and 5months later. Educational progress and compliance with spectacle wear were assessed through school and parental reports.   Fourteen children and young adults with DS participated in the study. Eighty-five percent required bifocals with additions ranging from +1.00D to +3.50D. The mean near logMAR VA improved with bifocals (p=0.007) compared to SV lenses. Repeated measures anova showed that there was more accurate focus (less accommodative lag) through the bifocals (p=0.002), but no change in the accommodation exerted through the distance portion compared to SV lenses (p=0.423). There was a main effect of time on sight words (p=0.013), Word Identification (p=0.047), Visual Closure (p=0.006) and Visual Form Constancy (p=0.001). Bifocals provide clearer near vision in DS children with reduced accommodation. This is shown by improved VA and decreased lag of accommodation. The results indicate that the improvement in VA results in improved scores in early literacy skills. Better compliance with bifocals over SV lenses was seen. © 2010 The Authors. Journal compilation © 2010 Acta Ophthalmol.

  19. Comparison of visual acuity levels in pediatric patients with amblyopia using Wright figures, Allen optotypes, and Snellen letters.

    Science.gov (United States)

    Mocan, Mehmet Cem; Najera-Covarrubias, Mario; Wright, Kenneth W

    2005-02-01

    To compare and correlate the clinical performance of Wright figures in visual acuity assessments of pediatric patients with amblyopia to those obtained through Allen cards and Snellen letters. Best-corrected visual acuity of 26 amblyopic children were measured with the Wright figures(c), Snellen letters, and isolated Allen optotypes, respectively. Amblyopia was defined as two lines of visual acuity difference or a visual acuity level of 20/30 or lower as determined by Snellen chart. The results were evaluated for statistical intergroup differences using the Wilks' Lambda multivariate analysis of variance and for correlation using the Pearson correlation coefficient test. The mean age of the subjects was 8.27 +/- 2.46 years (range: 5 to 15 years). The mean logMAR values for the Wright figures(c), Snellen letters, and Allen optotypes were 0.40 +/- 0.20, 0.47 +/- 0.23, and 0.29 +/- 0.28, respectively. When compared with Snellen letters, the Wright figures correlated to a higher degree ( r = 0.46, P Snellen letter testing, the sensitivity of Wright figures(c) and Allen cards in diagnosing amblyopic eyes was 87.0 and 56.5%, respectively ( P = 0.016). Wright figures, designed primarily to evaluate the vision in the preliterate pediatric population, correlate more closely to Snellen letters and have a higher rate of correctly identifying amblyopia than isolated Allen optotypes in pediatric patients.

  20. Prospective evaluation of visual acuity assessment: a comparison of snellen versus ETDRS charts in clinical practice (An AOS Thesis).

    Science.gov (United States)

    Kaiser, Peter K

    2009-12-01

    first, to prospectively compare visual acuity (VA) scores obtained with Snellen charts versus Early Treatment Diabetic Retinopathy Study (ETDRS) charts in a "real world" retinal practice, and second, to see if there was a difference in visual acuity measurements obtained with ETDRS charts starting at 4 or 2 meters. Prospective, consecutive evaluation of patients who underwent best-corrected visual acuity testing of their right eye performed at a single seating by the same experienced, certified vision examiner in the same room with standardized low light conditions using a projected Snellen chart at 20 feet, and two different back-illuminated ETDRS charts placed 4 and 2 meters from the patient. One hundred sixty-three eyes were included in the study. The mean Snellen VA was 0.67 logMAR (20/94), ETDRS VA at 4 meters was 0.54 logMAR (~20/69), and ETDRS VA at 2 meters was 0.51 logMAR (~20/65). The mean difference was 6.5 letters better on the ETDRS chart (P=.000000001). As the VA worsened, there was increased variability between the charts and the mean discrepancy between charts also increased. Subgroup analysis revealed the greatest difference between charts was in the poor vision subgroup (Snellen charts. The difference was greatest with poor visual acuity (<20/200) and in patients with exudative AMD. Thus, caution should be exercised when comparing data using the different charts.

  1. Comparative study of visual acuity and aberrations after intralase femtosecond LASIK: small corneal flap versus big corneal flap

    Institute of Scientific and Technical Information of China (English)

    Ya-Li; Zhang; Lei; Liu; Chang-Xia; Cui; Ming; Hu; Zhao-Na; Li; Li-Jun; Cao; Xiu-Hua; Jing; Guo-Ying; Mu

    2014-01-01

    AIM:To study the effects of different flap sizes on visual acuity, refractive outcomes, and aberrations after femtosecond laser for laser keratomileusis (LASIK). ·METHODS: In each of the forty patients enrolled, 1 eye was randomly assigned to receive treatment with a 8.1mm diameter corneal flap, defined as the small flap, while the other eye was treated with a 8.6mm diameter corneal flap, defined as the big flap. Refractive errors, visual acuity, and higher -order aberrations were compared between the two groups at week 1, month 1 and 3 postoperatively. · RESULTS: The postoperative refractive errors and visual acuity all conformed to the intended goal. Postoperative higher -order aberrations were increased, especially in spherical aberration (Z12) and vertical coma (Z7). There were no statistically significant differences between the two groups in terms of postoperative refractive errors, visual acuity, root mean square of total HOAs (HO -RMS), trefoil 30° (Z6), vertical coma (Z7), horizontal coma (Z8), trefoil 0° (Z9), and spherical aberration (Z12) at any point during the postoperative follow-up. ·CONCLUSION: Both the small and big flaps are safe and effective procedures to correct myopia, provided the exposure stroma meets the excimer laser ablations. The personalized size corneal flap is feasible, as we can design the size of corneal flap based on the principle that the corneal flap diameter should be equal to or greater than the sum of the maximum ablation diameter and apparatus error.

  2. Clinical effect of Conbercept to improve visual acuity of patients with wet age-related macular degeneration

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    Zhen-Liu Zhu

    2015-11-01

    Full Text Available AIM:To observe the clinical effect of conbercept to improve visual acuity of patients with wet age-related macular degeneration(wAMD. METHODS:Seventy patients(70 eyeswith wAMD were selected and divided into study group and control group according to different therapies. The control group received intravitreal injection of triamcinolone acetonide. The study group adopted the intravitreal injection with conbercept. Uncorrected visual acuity, the score of reading ability, the central macular thickness(CMTand the macular pigment optical density of two groups before and after treatment was observed. RESULTS: the visual acuity of study group was 0.47±0.11 and 0.60±0.14 respectively at 6mo and 1a after treatments, those of control group were 0.27±0.09 and 0.30±0.15. The differences between the two groups at the two points were statistically significant(PPPCONCLUSION:The intravitreal injection with conbercept has a favorable clinical effect on the treatment of wAMD, Which can greatly improve the uncorrected visual acuity and is worthy promotion.

  3. The Prevalence of Visual Acuity Impairment among School Children at Arada Subcity Primary Schools in Addis Ababa, Ethiopia

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    Haile Fentahun Darge

    2017-01-01

    Full Text Available Background. Visual impairment and blindness are major public health problems in developing countries where there is no enough health-care service. Objective. To determine the prevalence of visual impairment among school children. Materials and Methods. A school-based cross-sectional study was conducted between 15 June 2015 and 30 November 2015 at Arada subcity primary schools, Addis Ababa, Ethiopia. Two schools were selected randomly, and 378 students were screened from grades 1 to 8 using systematic random sampling method. Snellen chart was used for visual acuity test. Students who had visual acuity of ≤6/12 were further examined by an ophthalmologist to diagnose the reason for low vision. Data was analyzed using SPSS version 20. Results. A total of 378 students were screened, and 192 (50.8% were females and the remaining 186 (49.2% were males. The prevalence of visual impairment (VA of ≤6/12 on either eye was 5.8%, VA < 6/18 on either eye was 1.1%, and VA < 6/18 on the better eye was 0.53%. In this study, color blindness [OR: 19.65, 95% CI (6.01–64.33] was significantly associated with visual acuity impairment. Conclusion. The prevalence of visual impairment among school children in the study area was 5.8% and school screening is recommended.

  4. The Prevalence of Visual Acuity Impairment among School Children at Arada Subcity Primary Schools in Addis Ababa, Ethiopia

    Science.gov (United States)

    Shibru, Getahun; Mulugeta, Abiy

    2017-01-01

    Background Visual impairment and blindness are major public health problems in developing countries where there is no enough health-care service. Objective To determine the prevalence of visual impairment among school children. Materials and Methods A school-based cross-sectional study was conducted between 15 June 2015 and 30 November 2015 at Arada subcity primary schools, Addis Ababa, Ethiopia. Two schools were selected randomly, and 378 students were screened from grades 1 to 8 using systematic random sampling method. Snellen chart was used for visual acuity test. Students who had visual acuity of ≤6/12 were further examined by an ophthalmologist to diagnose the reason for low vision. Data was analyzed using SPSS version 20. Results A total of 378 students were screened, and 192 (50.8%) were females and the remaining 186 (49.2%) were males. The prevalence of visual impairment (VA) of ≤6/12 on either eye was 5.8%, VA color blindness [OR: 19.65, 95% CI (6.01–64.33)] was significantly associated with visual acuity impairment. Conclusion The prevalence of visual impairment among school children in the study area was 5.8% and school screening is recommended. PMID:28706737

  5. The Prevalence of Visual Acuity Impairment among School Children at Arada Subcity Primary Schools in Addis Ababa, Ethiopia.

    Science.gov (United States)

    Darge, Haile Fentahun; Shibru, Getahun; Mulugeta, Abiy; Dagnachew, Yinebeb Mezgebu

    2017-01-01

    Visual impairment and blindness are major public health problems in developing countries where there is no enough health-care service. To determine the prevalence of visual impairment among school children. A school-based cross-sectional study was conducted between 15 June 2015 and 30 November 2015 at Arada subcity primary schools, Addis Ababa, Ethiopia. Two schools were selected randomly, and 378 students were screened from grades 1 to 8 using systematic random sampling method. Snellen chart was used for visual acuity test. Students who had visual acuity of ≤6/12 were further examined by an ophthalmologist to diagnose the reason for low vision. Data was analyzed using SPSS version 20. A total of 378 students were screened, and 192 (50.8%) were females and the remaining 186 (49.2%) were males. The prevalence of visual impairment (VA) of ≤6/12 on either eye was 5.8%, VA visual acuity impairment. The prevalence of visual impairment among school children in the study area was 5.8% and school screening is recommended.

  6. A neural computation for visual acuity in the presence of eye movements.

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    Xaq Pitkow

    2007-12-01

    Full Text Available Humans can distinguish visual stimuli that differ by features the size of only a few photoreceptors. This is possible despite the incessant image motion due to fixational eye movements, which can be many times larger than the features to be distinguished. To perform well, the brain must identify the retinal firing patterns induced by the stimulus while discounting similar patterns caused by spontaneous retinal activity. This is a challenge since the trajectory of the eye movements, and consequently, the stimulus position, are unknown. We derive a decision rule for using retinal spike trains to discriminate between two stimuli, given that their retinal image moves with an unknown random walk trajectory. This algorithm dynamically estimates the probability of the stimulus at different retinal locations, and uses this to modulate the influence of retinal spikes acquired later. Applied to a simple orientation-discrimination task, the algorithm performance is consistent with human acuity, whereas naive strategies that neglect eye movements perform much worse. We then show how a simple, biologically plausible neural network could implement this algorithm using a local, activity-dependent gain and lateral interactions approximately matched to the statistics of eye movements. Finally, we discuss evidence that such a network could be operating in the primary visual cortex.

  7. Retrospective, controlled observational case study of patients with central retinal vein occlusion and initially low visual acuity treated with an intravitreal dexamethasone implant.

    Science.gov (United States)

    Winterhalter, Sibylle; Vom Brocke, Gerrit Alexander; Pilger, Daniel; Eckert, Annabelle; Schlomberg, Juliane; Rübsam, Anne; Klamann, Matthias Karl; Gundlach, Enken; Dietrich-Ntoukas, Tina; Joussen, Antonia Maria

    2016-10-27

    Patients with initially low visual acuity were excluded from the therapy approval studies for retinal vein occlusion. But up to 28 % of patients presenting with central retinal vein occlusion have a baseline BCVA of less than 34 ETDRS letters (0.1). The purpose of our study was to assess visual acuity and central retinal thickness in patients suffering from central retinal vein occlusion and low visual acuity (central retinal vein occlusion, which were treated with a dexamethasone implantation. Visual acuity, central retinal thickness and intraocular pressure were measured monthly. Analyses were performed separately for eyes with visual acuity central retinal thickness, however, was reduced in both groups, falling from 694 to 344 μm (1 month; p = 0.003,) to 361 μm (2 months; p = 0,002) and to 415 μm (3 months; p = 0,004) in the low visual acuity group and from 634 to 315 μm (1 month; p central retinal vein occlusion and initially low visual acuity, a dexamethasone implantation can lead to an important reduction of central retinal thickness but may be of limited use to increase visual acuity.

  8. Prospective Evaluation of Visual Acuity Assessment: A Comparison of Snellen Versus ETDRS Charts in Clinical Practice (An AOS Thesis)

    Science.gov (United States)

    Kaiser, Peter K.

    2009-01-01

    Purpose: The purpose of this study was twofold: first, to prospectively compare visual acuity (VA) scores obtained with Snellen charts versus Early Treatment Diabetic Retinopathy Study (ETDRS) charts in a “real world” retinal practice, and second, to see if there was a difference in visual acuity measurements obtained with ETDRS charts starting at 4 or 2 meters. Methods: Prospective, consecutive evaluation of patients who underwent best-corrected visual acuity testing of their right eye performed at a single seating by the same experienced, certified vision examiner in the same room with standardized low light conditions using a projected Snellen chart at 20 feet, and two different back-illuminated ETDRS charts placed 4 and 2 meters from the patient. Results: One hundred sixty-three eyes were included in the study. The mean Snellen VA was 0.67 logMAR (20/94), ETDRS VA at 4 meters was 0.54 logMAR (~20/69), and ETDRS VA at 2 meters was 0.51 logMAR (~20/65). The mean difference was 6.5 letters better on the ETDRS chart (P=.000000001). As the VA worsened, there was increased variability between the charts and the mean discrepancy between charts also increased. Subgroup analysis revealed the greatest difference between charts was in the poor vision subgroup (<20/200) with a difference of 0.2 logMAR (10 letters; P=.0000002). Patients with exudative age-related macular degeneration (AMD) had the greatest disparity on vision testing, but patients with dry AMD and diabetic retinopathy also exhibited significant differences. Conclusions: Visual acuity scores were significantly better on ETDRS charts compared to Snellen charts. The difference was greatest with poor visual acuity (<20/200) and in patients with exudative AMD. Thus, caution should be exercised when comparing data using the different charts. PMID:20126505

  9. CHARACTERISTICS OF MACULAR REGION AND VISUAL ACUITY IN GLAUCOMA PATIENTS AFTER PHACOEMULSIFICATION CATARACT SURGERY

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    E. N. Mityaeva

    2015-01-01

    Full Text Available Background: To improve safety of phacoemulsification cataract surgery, innovative technologies have been developed. Assessment of macular region status after the use of routine and innovative phaco technologies is of great interest. Aim: To compare effects of different phaco technologies on macular retina, visual acuity and intraocular pressure in patients with compensated glaucoma after uncomplicated phaco with intraocular lens implantation. Materials and methods: Phacoemulsification of immature cataract was performed in 52  patients (52 eyes using Oertli machine and uniform method. Patients were divided into 3 groups. Group 1 included 20  patients (20  eyes with simple (primary openangle glaucoma (POAG after phaco using easyPhaco technology. Group 2 included 20  POAG patients (20  eyes after phaco using routine technology. Group  3 included 12  patients without glaucoma after routine phaco. EasyPhaco technology involves using of the new Oertli machine parameters, phaco tip with new geometry, flow rate/vacuum setting of 1:10. Preoperatively, in all 40 patients with glaucoma, normal values of intraocular pressure were achieved using antiglaucomatous therapies. Visual acuity, intraocular pressure and macular thickness by optical coherent tomography were measured before the surgery, in 1 and 6 weeks after the procedure. Results: Increase of macular thickness (by 12–30  mcm compared to baseline was observed postoperatively in patients with and without glaucoma. After 1 week, mean macular thickness was significantly less in the easyPhaco group compared to routine phaco groups with and without glaucoma (221.5±15.4;238.3 ± 11.5 and 229.3 ± 16.9 mcm,respectively, p < 0.05. In the groups 1 and 3, macular thickness returned to preoperative values after 6 weeks (group 1: 210.5 ± 13.8 and 209.7 ± 16.3 mcm; group  3: 211.1 ± 14.4 and 211.1 ± 15.8  mcm,respectively. By contrast, after routine phaco technology in POAG

  10. Ethanol consumption impairs vestibulo-ocular reflex function measured by the video head impulse test and dynamic visual acuity.

    Science.gov (United States)

    Roth, Thomas N; Weber, Konrad P; Wettstein, Vincent G; Marks, Guy B; Rosengren, Sally M; Hegemann, Stefan C A

    2014-01-01

    Ethanol affects many parts of the nervous system, from the periphery to higher cognitive functions. Due to the established effects of ethanol on vestibular and oculomotor function, we wished to examine its effect on two new tests of the vestibulo-ocular reflex (VOR): the video head impulse test (vHIT) and dynamic visual acuity (DVA). We tested eight healthy subjects with no history of vestibular disease after consumption of standardized drinks of 40% ethanol. We used a repeated measures design to track vestibular function over multiple rounds of ethanol consumption up to a maximum breath alcohol concentration (BrAC) of 1.38 per mil. All tests were normal at baseline. VOR gain measured by vHIT decreased by 25% at the highest BrAC level tested in each subject. Catch-up saccades were negligible at baseline and increased in number and size with increasing ethanol consumption (from 0.13° to 1.43° cumulative amplitude per trial). DVA scores increased by 86% indicating a deterioration of acuity, while static visual acuity (SVA) remained unchanged. Ethanol consumption systematically impaired the VOR evoked by high-acceleration head impulses and led to a functional loss of visual acuity during head movement.

  11. 单眼弱视者的空间视觉缺损及其与弱视程度的相关性研究%Correlation between space visual defect of monocular amblyopia and the degree of amblyopia

    Institute of Scientific and Technical Information of China (English)

    杜娟; 罗红

    2015-01-01

    目的:研究单眼弱视者的空间视觉缺损模式及其与弱视程度的相关性,探讨连续全遮盖治疗的临床效果。方法回顾性分析我院2011年8月至2014年4月期间,于我科治疗的65例单眼弱视患者的临床资料,均予以连续全遮盖方式治疗,疗程12周,通过治疗效果,对比患者治疗前后双眼的视力、视锐度、AULCSF (对比敏感度函数的曲线下面积)、Smax (峰值对比敏感度)、Frmax (Smax空间频率)、CutSF (截止空间频率),评价弱视程度对空间视觉缺损所产生的影响。结果经12周治疗后,患者患眼视力、AULCSF、CutSF与治疗前相比较,差异均有统计学意义(P0.05)。视锐度、AULCSF、Smax、Frmax、CutSF在患眼不同弱视程度下差异均有显著统计学意义(P0.05). Visual acuity, AULCSF, Smax, Frmax, CutSF had statistically sig-nificant difference between different degrees of amblyopia (P<0.01), and Smax, Frmax, CutSF decreased with the de-gree of amblyopia eyes increased. Conclusion In patients with monocular amblyopia, AULCSF, Smax, Frmax, CutSF show a trend of consistency with visual sharpness and space visual defects. If the space visual defects deterio-rate, the corresponding degree of amblyopia would get worse. If high frequency contrast and resolution are reduced, the risk of eye spatial frequency will also show low frequency offset. For monocular amblyopia, continuous full cover treatment can improve the visual to the high frequency resolution, and not reduce visual function of eye.

  12. Influence of visual acuity on anxiety, panic and depression disorders among young and middle age adults in the United States.

    Science.gov (United States)

    Loprinzi, Paul D; Codey, Kathleen

    2014-01-01

    Previous research, albeit limited, has demonstrated an association of visual acuity with depression and anxiety. However, these studies are limited in that they have focused on older adults, used a convenient sample, and/or used a subjective assessment of visual function. As a result, the purpose of this study was to examine the association of objectively-measured visual acuity with depression and anxiety (and panic disorder) among a national sample of young- and middle-age U.S. adults (20-39 years). Using data from the 2003-2004 NHANES (n=602), the presence of anxiety, depression, and panic disorders was assessed from a diagnostic interview. Visual acuity was assessed from a vision exam using the Nidek Auto Lensmeter Model (LM-990A) and expressed as LogMAR units. After adjusting for age, gender, race-ethnicity, body mass index, mean arterial pressure, cotinine, diabetes, and physical activity, visual acuity was not associated with panic disorder (p=0.71) or depression disorder (p=0.20), but for every 0.1 LogMAR unit change in vision, participants had a 14% (OR=1.14; p=0.04) higher odds of having an anxiety disorder. The main limitation of this study was the cross-sectional design. Young- and middle-age U.S. adults with worse visual function are at increased odds of having an anxiety disorder. Strategies to prevent and treat anxiety among those with worse visual function are needed. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Nerve growth factor eye drops improve visual acuity and electrofunctional activity in age-related macular degeneration: a case report

    Directory of Open Access Journals (Sweden)

    Alessandro Lambiase

    2009-12-01

    Full Text Available Age-related macular degeneration (ARMD is a severe disease affecting visual function in the elderly. Currently available surgical and medical options do not guarantee a significant impact on the outcome of the disease. We describe the effects of nerve growth factor eye drop treatment in a 94 years old female with ARMD, whose visual acuity was progressively worsening in spite of previous surgical and medical treatments. NGF eye drops improved visual acuity and electrofunctional parameters as early as 3 months after initiation of treatment. These results are in line with previous reports on a neuroprotective effect of NGF on retinal cells and on NGF eye drops bioavailability in the retina and optic nerve. No side effects were observed after five years of follow-up, suggesting that topical NGF treatment may be a safe and effective therapy for ARMD.

  14. Origins of superior dynamic visual acuity in baseball players: superior eye movements or superior image processing.

    Directory of Open Access Journals (Sweden)

    Yusuke Uchida

    Full Text Available Dynamic visual acuity (DVA is defined as the ability to discriminate the fine parts of a moving object. DVA is generally better in athletes than in non-athletes, and the better DVA of athletes has been attributed to a better ability to track moving objects. In the present study, we hypothesized that the better DVA of athletes is partly derived from better perception of moving images on the retina through some kind of perceptual learning. To test this hypothesis, we quantitatively measured DVA in baseball players and non-athletes using moving Landolt rings in two conditions. In the first experiment, the participants were allowed to move their eyes (free-eye-movement conditions, whereas in the second they were required to fixate on a fixation target (fixation conditions. The athletes displayed significantly better DVA than the non-athletes in the free-eye-movement conditions. However, there was no significant difference between the groups in the fixation conditions. These results suggest that the better DVA of athletes is primarily due to an improved ability to track moving targets with their eyes, rather than to improved perception of moving images on the retina.

  15. Relation between Visual Acuity and Slope of Psychometric Function in Young Adults

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    Tomoki Tokutake

    2011-05-01

    Full Text Available Mita et al. (2010 devised a technique of comparing a visual acuity (VA change in an individual with more accurate VA than conventional VA tests by significant difference examined logarithmic (Log VA ± standard deviation (SD. Using this technique, in this study, we examined a relation between VA and the slope of the psychometric function in normal young subjects. Six occlusion foil conditions were employed (1.0, 0.8, 0.6, 0.4, 0.1 and without the foil under a full refractive correction. Ten normal young adults (22.8 years old on average who have no ophthalmologic disease except ametropia participated in the measurement. The experiment was carried out with the constant method, a series of ten Landolt rings were used and each ring was presented 20 times randomly in a measurement. A 5.6-inch type of liquid crystal display driven by a computer, which has 1,280×800 pixels spatial resolution, was used to present the stimulus. In the normal young adults, the slope of the psychometric function did not change as the VA change systematically, and there was almost no correlation between them (r = −0.103.

  16. Aircrew visual acuity viewing with different night vision goggle eyepiece diopter settings

    Science.gov (United States)

    Angel, Share-Dawn P.; Baldwin, J. Bruce

    2004-09-01

    The AN/AVS-9 night vision goggle (NVG) has an eyepiece lens that can be adjusted from +2 to -6 diopters (D). We have shown previously1,2,3 that on average NVG users tend to select about -1D, with a range of +0.5D to -4D3. This study was designed to evaluate NVG visual acuity (NVG VA) and subjective ratings for a range of diopter settings including user-selected and three fixed settings of -0.25D, -1D and -2D. Twenty-one experienced USAF Special Operations aircrew members, including 15 pilots, served as subjects. The median user-selected setting was -1.25D and ranged from +0.5D to -3.5D. Only 2 of the 21 subjects had user-selected NVG VA significantly better than a fixed setting of -1D. Of those two, one was not wearing prescribed glasses and the other was 49 years old, presbyopic, and could not focus through the -1D lenses. Subjective ratings and NVG VA indicated that most people could fly with a fixed setting of -1D for each eye, although two individuals needed different diopter settings for the right and left eyes. The new Panoramic NVG (PNVG) has a fixed eyepiece focus of -1D. Results suggest the PNVG should have a limited set of accessory lenses available.

  17. Predictive factors for postoperative visual acuity in idiopathic epiretinal membrane: a systematic review.

    Science.gov (United States)

    Scheerlinck, Laura M E; van der Valk, Rikkert; van Leeuwen, Redmer

    2015-05-01

    The aim of this study was to review the literature on predictive factors for postoperative visual acuity (VA) in surgery for idiopathic epiretinal membrane (ERM). A systematic review of the literature in the databases of PubMed and Embase was performed. The risk of bias was assessed based on predefined criteria and the results were summarized. In total, 1927 studies were retrieved of which 35 were potentially eligible. Nineteen studies were of adequate quality in terms of bias. Preoperative VA, central foveal thickness (CFT) and inner segment/outer segment (IS/OS) integrity on optical coherence tomography (OCT) were most extensively studied. Other preoperative factors studied were severity of metamorphopsia, several OCT parameters, fundus autofluorescence and multifocal electroretinogram. In the current literature, preoperative VA is the only variable consistently associated with postoperative VA. IS/OS integrity on OCT is probably associated, and the severity of metamorphopsia, cone outer segment tips integrity and fundus autofluorescence are possibly associated with postoperative VA. CFT is not associated with postoperative VA. Further studies with adequate methodological quality are needed to confirm these findings. Therefore, an overall prediction model, including different parameters, is still awaited.

  18. MEASUREMENTS OF VISUAL ACUITY, CARDIOVASCULAR AND ANTHROPOMETRIC PARAMETERS AMONG NKWU' CONSUMERS IN MID-WESTERN NIGERIA

    Institute of Scientific and Technical Information of China (English)

    ONYESOM I; NAIHO A

    2006-01-01

    'Nkwu' is the generic name for all kinds of alcoholic liquors locally brewed from palm sap. It is the beverage commonly consumed in the mid-western and eastern Nigeria. No information is yet available on the parameters, body mass index and visual acuity. Seven hundred and thirty-eight apparently healthy-looking, and most suitable men, who gave their consent were selected after interview. The results showed that long induced significant increase in mean blood pressure parameters (systolic blood pressure, diastolic blood pressure, mean arterial blood pressure and pulse rate) in older men (41-50 and 51-60 age brackets) when compared with their respective age-matched control (non-drinkers) mean value. Such drinking pattern also significantly (P<0.05) reduced their body mass index when compared with similar control values. By extension, it can be cardiovascular dysfunction and nutritional complications. However, further epidemiological, biochemical and post-mortem investigations are required in order to generate data and information needed to alert the communities, and possibly advise the lay public.

  19. Baseline predictors of visual acuity and retinal thickness in patients with retinal vein occlusion.

    Science.gov (United States)

    Kim, Sang Jin; Yoon, Young Hee; Kim, Ha Kyoung; Yoon, Hee Seong; Kang, Se Woong; Kim, June-Gone; Park, Kyu Hyung; Jo, Young Joon; Lee, Dong-Hoon

    2015-04-01

    This study investigated the baseline predictors of best corrected visual acuity (BCVA) and central retinal thickness (CRT) at 6 months in patients with treatment-naïve branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). This multicenter, interventional case series included 208 BRVO and 123 CRVO patients with follow-up period of 6 months or more. Outcome measures of BCVA (logMAR) included absolute change from baseline and a gain or loss of ≥ 0.3 from baseline. Outcome measures of CRT included absolute change from baseline and a measurement of ≤ 250 µm or ≥ 400 µm at 6 months. Univariate and multiple regression analyses were done to find baseline predictors. For BRVO, younger age, worse baseline BCVA, and shorter duration of symptom were associated with more gain in BCVA. For CRVO, worse baseline BCVA was associated with more gain in BCVA. For CRT outcomes, higher baseline CRT predicted greater decrease at 6 months in both BRVO and CRVO. Younger age and better baseline BCVA were associated with an increased likelihood of measurement of a ≤ 250 µm outcome for BRVO and CRVO, respectively. For CRVO, smoking was associated with greater decrease from baseline and decreased likelihood of measurement of a CRT ≥ 400 µm at 6 months. In conclusion, several baseline factors including age, symptom duration, and baseline BCVA and CRT are associated with BCVA and CRT outcomes at 6 months, which may help to predict disease course for RVO patients.

  20. Metformin Impairs Spatial Memory and Visual Acuity in Old Male Mice

    Science.gov (United States)

    Thangthaeng, Nopporn; Rutledge, Margaret; Wong, Jessica M.; Vann, Philip H.; Forster, Michael J.; Sumien, Nathalie

    2017-01-01

    Metformin is an oral anti-diabetic used as first-line therapy for type 2 diabetes. Because benefits of metformin extend beyond diabetes to other age-related pathology, and because its effect on gene expression profiles resembles that of caloric restriction, metformin has a potential as an anti-aging intervention and may soon be assessed as an intervention to extend healthspan. However, beneficial actions of metformin in the central nervous system have not been clearly established. The current study examined the effect of chronic oral metformin treatment on motor and cognitive function when initiated in young, middle-aged, or old male mice. C57BL/6 mice aged 4, 11, or 22 months were randomly assigned to either a metformin group (2 mg/ml in drinking water) or a control group. The mice were monitored weekly for body weight, as well as food and water intake and a battery of behavioral tests for motor, cognitive and visual function was initiated after the first month of treatment. Liver, hippocampus and cortex were collected at the end of the study to assess redox homeostasis. Overall, metformin supplementation in male mice failed to affect blood glucose, body weights and redox homeostasis at any age. It also had no beneficial effect on age-related declines in psychomotor, cognitive or sensory functions. However, metformin treatment had a deleterious effect on spatial memory and visual acuity, and reduced SOD activity in brain regions. These data confirm that metformin treatment may be associated with deleterious effect resulting from the action of metformin on the central nervous system. PMID:28203479

  1. COMPARISON OF VISUAL ACUITY IN REDUCED LUMINATION AND FACILITY OF OCULAR ACCOMMODATION IN TABLE TENNIS CHAMPIONS AND NON- PLAYERS

    Directory of Open Access Journals (Sweden)

    Ebrahim Jafarzadehpur

    2004-03-01

    Full Text Available A table tennis player should fixate at different distances; track the objects with different speed, and in different visual environment. Their visual skills must be well developed for these capabilities. Therefore, visual acuity in reduced lumination and facility of ocular accommodation those are two criteria for visual skills have been compared in table tennis players and normal non-players. Twenty-nine young table tennis champions and 29 normal matched non-players (did not take part in any racket sports game were evaluated. Basic visual and eye examinations were done for both of them. Normal results in basic examination were fundamental requirement for all the subjects. +/-2.00 sphere lenses for accommodation facility are used. An electrical current regulator changed the output light intensity of a conventional chart projector (Topcon. Light intensity decreased to 10 cd·m-2 and visual acuity tested. In comparison of visual acuity in reduced lumination and facility of ocular accommodation in table tennis champions and non-players there are significant differences (p < 0.001. In the preliminary visual tests there was not any significant different in the two groups but the results in the top level table tennis player was very uniform and in every test and the standard deviation was lesser in tennis player group than non-players. These results show that motor and sensorial functions of expert players are well developed. That is consistent with other researchers. This result was interpreted as reflecting a better perceptual system of experts to the constraints encountered during table tennis and its use in practical settings for evaluating athletes or detecting sport talents. However some visual and perceptual training that usually used in orthoptics can be used for novice table tennis player to improve their abilities

  2. How well do you see what you hear? The acuity of visual-to-auditory sensory substitution

    Directory of Open Access Journals (Sweden)

    Alastair eHaigh

    2013-06-01

    Full Text Available Sensory substitution devices (SSDs aim to compensate for the loss of a sensory modality, typically vision, by converting information from the lost modality into stimuli in a remaining modality. The vOICe is a visual-to-auditory SSD which encodes images taken by a camera worn by the user into soundscapes such that an experienced user can extract information about their surroundings. Here we investigated how much detail was resolvable during the early induction stages by testing the acuity of blindfolded sighted, naïve vOICe users. Initial performance was well above chance. Participants who took the test twice as a form of minimal training showed a marked improvement on the second test. Acuity was slightly but not significantly impaired when participants wore a camera and judged letter orientations live. A positive correlation was found between participants’ musical training and their acuity. The relationship between auditory expertise via musical training and the lack of a relationship with visual imagery, suggests that early use of a sensory substitution device draws primarily on the mechanisms of the sensory modality being used rather than the one being substituted. If vision is lost, audition represents the sensory channel of highest bandwidth of those remaining. The level of acuity found here, and the fact it was achieved with very little experience in sensory substitution by naïve users is promising.

  3. Visual Servo Tracking Control of a Wheeled Mobile Robot with a Monocular Fixed Camera

    Science.gov (United States)

    2004-01-01

    41), it is clear that the controller developed in the previous section can not be applied to solve the regulation problem . In this section, an...extension is presented to illustrate how a visual servo controller can be developed to solve the regulation problem for the fixed camera configuration. To

  4. Comment on amniotic membrane covering promotes healing of cornea epithelium and improves visual acuity after debridement for fungal keratitis

    Institute of Scientific and Technical Information of China (English)

    Ahmet; Tas; Abdullah; Ilhan; Umit; Yolcu; Uzeyir; Erdem

    2015-01-01

    <正>Dear Editor,We congratulate Zeng et al[1]for their study entitled"Amniotic membrane covering promotes healing of cornea epithelium and improves visual acuity after debridement for fungal keratitis".The authors endeavored to present an alternative method for ophthalmologists in the treatment of a challenging case.We would like to express our reservations and ask for the attitudes of the authors about

  5. Macular edema in central retinal vein occlusion: correlation between optical coherence tomography, angiography and visual acuity.

    Science.gov (United States)

    Martinet, Virginie; Guigui, Benjamin; Glacet-Bernard, Agnès; Zourdani, Alain; Coscas, Gabriel; Soubrane, Gisèle; Souied, Eric H

    2012-08-01

    To analyze the characteristics and the course of macular edema secondary to central retinal vein occlusion (CRVO) using optical coherence tomography (OCT) and to determine correlations between clinical, tomographic and angiographic data, in particular including retinal ischemia. In this retrospective study, 53 consecutive patients with CRVO were included. At each follow-up visit, patients underwent complete ophthalmological examination, including best-corrected visual acuity (BCVA) and OCT. Fluorescein angiography was performed at baseline and on demand during follow-up. 243 OCTs were analyzed. Mean age was 61 years and mean follow-up 13 months. The first structural change, observed very early after the onset of the occlusion, was a diffuse increase at the level of the outer nuclear layer without change at the level of the inner retina. This early change seemed characteristic of retinal vein occlusion. Cystoid spaces were subsequently observed in all retinal layers and were combined with serous retinal detachment in 51 %. During the first 6 months, central retinal thickness was higher in ischemic CRVO (mean, 691 μm) than in non-ischemic CRVO (mean, 440 μm, p central retinal thickness without subretinal fluid) of 700 μm or greater, peripheral ischemia was present in 69 % of eyes, final BCVA was 20/200 or less in 75 % and never reached 20/40 during follow-up. The integrity of the junction of the photoreceptors' inner and outer segments was correlated with a better prognosis (p < 0.05). Foveal thickness was inversely correlated to BCVA at each visit and could have a prognostic value. OCT examination in CRVO revealed useful data for the diagnosis of CRVO and its prognosis. The largest macular edemas seemed to be the hallmark of ischemic CRVO.

  6. Stroboscopic Goggles as a Countermeasure for Dynamic Visual Acuity and Landing Sickness in Crewmembers Returning from Long-Duration Spaceflight

    Science.gov (United States)

    Rosenberg, M. J. F.; Kreutzberg, G. A.; Peters, B. T.; Reschke, M. F.

    2017-01-01

    Long-term exposure to microgravity causes sensorimotor adaptations that result in functional deficits upon returning to a gravitational environment. At landing, the vestibular system and the central nervous system, responsible for coordinating head and eye movements via the vestibulo-occular reflex (VOR), are adapted to microgravity and must re-adapt to the Earth's gravitational environment. This re-adaptation causes decrements in gaze control and dynamic visual acuity, with astronauts reporting oscillopsia and blurred vision. These effects are caused by retinal slip, or the inability to keep an image focused on their retina, which is thought to drive motion sickness symptoms experienced upon landing. Retinal slip can be estimated by dynamic visual acuity (DVA); visual acuity while in motion. Peters et al. (2011) find that DVA is worsened in astronauts by an average of 0.75 eye-chart lines one day after landing. Previously, the use of stroboscopic goggles has shown to be effective in minimizing motion sickness symptoms due to retinal slip (Reschke et al. 2007). In this study, we simulated the decrement in DVA caused by sensorimotor re-adaptation by using minifying lenses and then testing the efficacy of stroboscopic goggles in preventing retinal slip and improving DVA. Dynamic visual acuity is assessed using an oscillating chair developed in the Neuroscience Laboratory at JSC. This chair is motor-driven and oscillates vertically at 2 Hz with a vertical displacement of +/- 2 cm to simulate the vertical translations that occur while walking. As the subject is being oscillated, they are asked to discern the direction of Landolt-C optotypes of varying sizes and record their direction using a gamepad. The visual acuity thresholds are determined using an algorithm that alters the size of the optotype based on the previous responses of the subject using a forced-choice best parameter estimation that is able to rapidly converge on the threshold value. Visual acuity

  7. Visual acuity, amplitude of accommodation and near point of convergence and academic achievement in primary school learners in Bloemfontein

    Directory of Open Access Journals (Sweden)

    Mariette Nel

    2014-08-01

    Full Text Available Introduction: Learning problems influencing the social and psychological development of children may result from poor visual acuity (VA, insufficient amplitude of accommodation and receded near point of convergence (NPC. This study assessed Grade 4 and 5 academic achievement (< 50%, 51-69% and ≥ 70% in relation to visual acuity, amplitude of accommodation and NPC. The study attempts to determine the association between these visual functions and academic performance. Methods: A cross-sectional study included a randomised sample of learners (n = 199 selected from five public schools in Bloemfontein. Information was obtained on each participant regarding history, visual acuity (distance and near, amplitude of accommodation and NPC (subjective and objective. Participant aggregates for the most recent school term and the grade average were compared to measures of these visual functions.Results: The children’s median age was 10.3 years (with range 8.7 to 12.7 years and 53.8% were female. More than 50% of children were Sesotho-speaking. Complaints revealed by his-tory-taking were mostly headaches (57.8% and eyestrain (58.3%. Regarding academic achievement, 18.6% of the learners were below average, 53.8% on average and 27.6% above average. Of the learners tested, 42.2% achieved a VA of 6/6 or better on both distance and near visual acuity. Amplitude of accommodation was less than the minimum requirements in 17.6% of participants. Approximately 30% of those below grade average did not meet the minimum requirements for amplitude of accommodation, compared to 13% of learners above grade average, which was statistically significant. More than 70% had a receded break point (> 5 cm for NPC and 85.7% had a receded recovery point (> 7 cm.Conclusion: Of the three visual functions evaluated in this study, the only visual function associated with academic achievement was amplitude of accommodation. It would thus be recommended that learners are screened for

  8. Layer- and cell-type-specific subthreshold and suprathreshold effects of long-term monocular deprivation in rat visual cortex.

    Science.gov (United States)

    Medini, Paolo

    2011-11-23

    Connectivity and dendritic properties are determinants of plasticity that are layer and cell-type specific in the neocortex. However, the impact of experience-dependent plasticity at the level of synaptic inputs and spike outputs remains unclear along vertical cortical microcircuits. Here I compared subthreshold and suprathreshold sensitivity to prolonged monocular deprivation (MD) in rat binocular visual cortex in layer 4 and layer 2/3 pyramids (4Ps and 2/3Ps) and in thick-tufted and nontufted layer 5 pyramids (5TPs and 5NPs), which innervate different extracortical targets. In normal rats, 5TPs and 2/3Ps are the most binocular in terms of synaptic inputs, and 5NPs are the least. Spike responses of all 5TPs were highly binocular, whereas those of 2/3Ps were dominated by either the contralateral or ipsilateral eye. MD dramatically shifted the ocular preference of 2/3Ps and 4Ps, mostly by depressing deprived-eye inputs. Plasticity was profoundly different in layer 5. The subthreshold ocular preference shift was sevenfold smaller in 5TPs because of smaller depression of deprived inputs combined with a generalized loss of responsiveness, and was undetectable in 5NPs. Despite their modest ocular dominance change, spike responses of 5TPs consistently lost their typically high binocularity during MD. The comparison of MD effects on 2/3Ps and 5TPs, the main affected output cells of vertical microcircuits, indicated that subthreshold plasticity is not uniquely determined by the initial degree of input binocularity. The data raise the question of whether 5TPs are driven solely by 2/3Ps during MD. The different suprathreshold plasticity of the two cell populations could underlie distinct functional deficits in amblyopia.

  9. Association Between Adherence to Glasses Wearing During Amblyopia Treatment and Improvement in Visual Acuity.

    Science.gov (United States)

    Maconachie, Gail D E; Farooq, Shegufta; Bush, Glen; Kempton, Julie; Proudlock, Frank A; Gottlob, Irene

    2016-12-01

    Occlusion dose monitors have helped establish that better adherence to occlusion is associated with improved visual outcomes in patients undergoing amblyopia treatment. However, the role of adherence to glasses wearing is unknown. To establish the feasibility and reliability of objectively monitoring adherence to glasses wearing using age-based norms, establish the association between adherence to glasses wearing and improvement in visual acuity (VA) after optical treatment and occlusion therapy, and analyze the effect of age, sex, refractive errors, type of amblyopia, and adherence to glasses wearing on improvement in VA. A prospective, observational, nonmasked, cohort study was conducted between June 8, 2008, and June 30, 2013, among patients at a pediatric ophthalmology clinic of a tertiary care hospital who were newly diagnosed with anisometropic and/or strabismic amblyopia and had not undergone previous treatment. The study consisted of a glasses phase (18 weeks) and a patching phase (glasses and occlusion for 10 hours per day for 12 weeks). Reliability of the glasses monitors was assessed by comparing diary entries and monitor recordings in adults. Objective monitoring of glasses wearing and occlusion. Adherence to glasses wearing (hours per day) and effect on VA. Among 20 children with anisometropia (mean [SD] age, 6.20 [2.16] years; 11 boys and 9 girls) and 20 with strabismic or mixed amblyopia (mean [SD] age, 4.90 [1.36] years; 10 boys and 10 girls), adherence to glasses wearing was successfully monitored in all but 1 patient. Agreement between diaries and monitored times wearing glasses in adults was high (intraclass correlation coefficient, 1.00; 95% CI, 0.999-1.00). Median (SD) adherence to glasses wearing was 70% (25.3%). A moderate correlation was observed between adherence to glasses wearing and percentage improvement in VA during the glasses phase (r = 0.462; P = .003). Multiple regression revealed that age (β = -0.535; P = .001

  10. Optic disc boundary segmentation from diffeomorphic demons registration of monocular fundus image sequences versus 3D visualization of stereo fundus image pairs for automated early stage glaucoma assessment

    Science.gov (United States)

    Gatti, Vijay; Hill, Jason; Mitra, Sunanda; Nutter, Brian

    2014-03-01

    Despite the current availability in resource-rich regions of advanced technologies in scanning and 3-D imaging in current ophthalmology practice, world-wide screening tests for early detection and progression of glaucoma still consist of a variety of simple tools, including fundus image-based parameters such as CDR (cup to disc diameter ratio) and CAR (cup to disc area ratio), especially in resource -poor regions. Reliable automated computation of the relevant parameters from fundus image sequences requires robust non-rigid registration and segmentation techniques. Recent research work demonstrated that proper non-rigid registration of multi-view monocular fundus image sequences could result in acceptable segmentation of cup boundaries for automated computation of CAR and CDR. This research work introduces a composite diffeomorphic demons registration algorithm for segmentation of cup boundaries from a sequence of monocular images and compares the resulting CAR and CDR values with those computed manually by experts and from 3-D visualization of stereo pairs. Our preliminary results show that the automated computation of CDR and CAR from composite diffeomorphic segmentation of monocular image sequences yield values comparable with those from the other two techniques and thus may provide global healthcare with a cost-effective yet accurate tool for management of glaucoma in its early stage.

  11. Visual evoked potentials (VEP and visual acuity improvement after cytidine 52 -diphosphocholine (CDP-Choline therapy in amblyopic patient

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    Regina Halfeld Furtado de Mendonça

    2012-10-01

    Full Text Available Citicoline may be used in many neurological disorders. Combined treatment of citicoline with patching in amblyopia has previously been researched. The purpose of this paper is to illustrate the effect of citicoline in non-patching amblyopic patient. A 11-year-old amblyopic boy underwent complete ophthalmological examinations, including VEP with flash and pattern stimulus. Two averages of 100 sweep were performed for flash stimulus. Pattern reversal stimulus obtained with high contrast was performed with 60', 30' and 15' checks stimuli. The VEP was repeated 90 days later after a therapy with citicoline and vitamin and the results compared with the responses of the previous recording session. The visual acuity (VA was 0,7 in the RE and 1,0 in the LE. The VEP pattern amplitude was normal in both eyes. Delayed in latency was detected for all spatial frequency stimulus (SFS in the RE. Delay in latency was detected only for high SFS in the LE. After the treatment, the VA was 1,0 in both eyes. The latency was normalized with low SFS on the RE and with high SFS on the LE. The flash VEP was normal before and after the therapy. In conclusion, the citicoline demonstrated that it was effective in the treatment of amblyopic eye without patching. The VA and the VEP latency improvement demonstrated that the citicoline enhance the transmission of the electric impulse from retina to visual cortex. Further research is required to understand the immediate and long-term effect of coline treatment in amblyopic patients.

  12. A novel monocular visual navigation method for cotton-picking robot based on horizontal spline segmentation

    Science.gov (United States)

    Xu, ShengYong; Wu, JuanJuan; Zhu, Li; Li, WeiHao; Wang, YiTian; Wang, Na

    2015-12-01

    Visual navigation is a fundamental technique of intelligent cotton-picking robot. There are many components and cover in the cotton field, which make difficulties of furrow recognition and trajectory extraction. In this paper, a new field navigation path extraction method is presented. Firstly, the color image in RGB color space is pre-processed by the OTSU threshold algorithm and noise filtering. Secondly, the binary image is divided into numerous horizontally spline areas. In each area connected regions of neighboring images' vertical center line are calculated by the Two-Pass algorithm. The center points of the connected regions are candidate points for navigation path. Thirdly, a series of navigation points are determined iteratively on the principle of the nearest distance between two candidate points in neighboring splines. Finally, the navigation path equation is fitted by the navigation points using the least squares method. Experiments prove that this method is accurate and effective. It is suitable for visual navigation in the complex environment of cotton field in different phases.

  13. Correlation between optical coherence tomography and multifocal electroretinogram findings with visual acuity in retinitis pigmentosa

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    Moschos MM

    2013-10-01

    Full Text Available Marilita M Moschos, Irini P Chatziralli, George Verriopoulos, Aristeides Triglianos, Dimitrios S Ladas, Dimitrios BrouzasLaboratory of Electrophysiology, First Department of Ophthalmology, University of Athens, Athens, GreeceIntroduction: Our purpose was to study the correlation between the macular morphology and function in eyes with retinitis pigmentosa (RP.Methods: Sixty-six eyes from 33 patients with RP and with different visual acuity (VA were studied using optical coherence tomography (OCT and multifocal electroretinogram (mfERG. Correlation analysis was performed between VA, macular thickness, mfERG amplitude, and latency.Results: Retinal thickness, retinal response density, and latency of the mfERG in the foveal area were independently and positively associated with VA (P = 0.002; P < 0.0001; P = 0.029; and P = 0.002, respectively, whereas there was no evidence for a correlation between VA and the amplitude of mfERG in the parafoveal area. Evidence of a correlation between the OCT and the mfERG evaluation was of borderline significance (P = 0.047. Also, there was evidence for an inverse association of VA with latency in ring 1 and ring 2 (b = -0.138; 95% confidence interval: -0.261, -0.015; P = 0.029. In accordance with the univariate findings, when foveal retinal thickness, mfERG amplitude, and latency in ring 1 were inserted simultaneously in the same model, all the three variables remained significantly associated with VA (P = 0.016; P < 0.0001; and P = 0.031, respectively. Nevertheless, some individual values deviated from the expected range. More specifically, 15 eyes showed a normal retinal thickness, whereas the respective VA was relatively low and the mfERG values were abnormal. Conversely, in seven eyes, despite the low retinal thickness, the respective VA was high.Conclusion: The combined use of OCT with mfERG appears to be more appropriate for the estimation of macular function.Keywords: retinitis pigmentosa, OCT, mfERG, VA

  14. A comparison of two methods of logMAR visual acuity data scoring for statistical analysis

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    O. A. Oduntan

    2009-12-01

    Full Text Available The purpose of this study was to compare two methods of logMAR visual acuity (VA scoring. The two methods are referred to as letter scoring (method 1 and line scoring (method 2. The two methods were applied to VA data obtained from one hundred and forty (N=140 children with oculocutaneous albinism. Descriptive, correlation andregression statistics were then used to analyze the data.  Also, where applicable, the Bland and Altman analysis was used to compare sets of data from the two methods.  The right and left eyes data were included in the study, but because the findings were similar in both eyes, only the results for the right eyes are presented in this paper.  For method 1, the mean unaided VA (mean UAOD1 = 0.39 ±0.15 logMAR. The mean aided (mean ADOD1 VA = 0.50 ± 0.16 logMAR.  For method 2, the mean unaided (mean UAOD2 VA = 0.71 ± 0.15 logMAR, while the mean aided VA (mean ADOD2 = 0.60 ± 0.16 logMAR. The range and mean values of the improvement in VA for both methods were the same. The unaided VAs (UAOD1, UAOD2 and aided (ADOD1, ADOD2 for methods 1 and 2 correlated negatively (Unaided, r = –1, p<0.05, (Aided, r = –1, p<0.05.  The improvement in VA (differences between the unaided and aided VA values (DOD1 and DOD2 were positively correlated (r = +1, p <0.05. The Bland and Altman analyses showed that the VA improvement (unaided – aided VA values (DOD1 and DOD2 were similar for the two methods. Findings indicated that only the improvement in VA could be compared when different scoring methods are used. Therefore the scoring method used in any VA research project should be stated in the publication so that appropriate comparisons could be made by other researchers.

  15. The Effect of Long Term Monocular Occlusion on Vernier Threshold: Elasticity in the Young Adult Visual System.

    Science.gov (United States)

    1986-06-01

    experiment, Brown and Salinger (1975) found a decrease of the X-cell 2 population in the lateral geniculate body of the adult cat. These investigators...D.L., and Salinger , W.L., "Loss of X-Cells in Lateral Geniculate Nucleus with Monocular Paralysis. Neural Plasticity in the Adult Cat", Science, 189

  16. The effect of tinted soft contact lens wear on functional visual acuity and higher-order aberrations.

    Science.gov (United States)

    Watanabe, Kazuhiro; Kaido, Minako; Ishida, Reiko; Dogru, Murat; Negishi, Kazuno; Tsubota, Kazuo

    2014-06-01

    To investigate the differences of functional visual acuity (FVA) and high order aberrations (HOAs) in relation to tinted and clear hydrogel soft contact lens (SCL) wear. A prospective comparative study was performed in 16 eyes of 16 healthy volunteers. Dynamic visual acuity (using a FVA measurement system) and higher-order aberrations (using a wavefront sensor) were compared in subjects wearing two types of soft contact lenses: 1-day Acuvue(®) (Vistakon, Jacksonville, FL) clear and the 1-day Acuvue(®) Define(TM) (Vistakon, Jacksonville, FL) tinted lens. The blink rates were recorded during FVA testing. The correlation between the difference of HOAs and differences in FVA values was analyzed. The mean LogMAR FVA scores with clear and tinted SCLs were 0.07 ± 0.13 and 0.14 ± 0.17 (P<0.05). The mean blink frequencies with clear and tinted SCL wear were 18.4 ± 8.3 and 25.3 ± 4.7 blinks/min (P<0.05). Both 3rd-order aberrations and total HOAs showed statistically significant differences between the two types of soft contact lenses for 6mm pupil measurements (P<0.05). A significant positive linear correlation was observed between ΔHOAs and ΔLogMAR FVA for 6mm pupil measurements (R=0.53, P=0.04). Tinted contact lens wear appears to induce a reduction in optical quality. Functional visual acuity measurement is a useful procedure to study the changes of visual performance and quality in tinted contact lens wear. Copyright © 2013 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  17. Tabelas para medir acuidade visual com escala logarítmica: porque usar e como construir Logarithmic visual acuity charts: reasons to use and how to design it

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    André Messias

    2010-02-01

    Full Text Available A acuidade visual representa o inverso do ângulo visual, ou seja, da menor distância angular entre dois pontos que podem ser vistos como separados. Apesar de ser a medida da função visual mais comum na prática oftalmológica, é muitas vezes interpretada erroneamente, principalmente devido às inúmeras tabelas e diferentes sistemas de notações empregados na clínica. Este artigo revisa alguns conceitos sobre a quantificação da acuidade visual, suas principais notações e tabelas de medida, discutindo as vantagens do uso da escala logarítmica.Visual acuity represents the visual angle or the smallest distance between two points that allows their discrimination as separated points. Although it is the most common clinical measurement of visual function, it is often misunderstood, especially due to the variety of charts and different notation systems employed for its quantification. This article reviews some concepts about visual acuity measurement, the main notation systems, type of charts and discuss the advantages of using logarithmic scales.

  18. Improvements in clinical and functional vision and perceived visual disability after first and second eye cataract surgery

    OpenAIRE

    Elliott, D; Patla, A.; Bullimore, M.

    1997-01-01

    AIMS—To determine the improvements in clinical and functional vision and perceived visual disability after first and second eye cataract surgery.
METHODS—Clinical vision (monocular and binocular high and low contrast visual acuity, contrast sensitivity, and disability glare), functional vision (face identity and expression recognition, reading speed, word acuity, and mobility orientation), and perceived visual disability (Activities of Daily Vision Scale) were measured in 25 subjects before a...

  19. Amniotic membrane covering promotes healing of cornea epithelium and improves visual acuity after debridement for fungal keratitis

    Institute of Scientific and Technical Information of China (English)

    Bo; Zeng; Ping; Wang; Ling-Juan; Xu; Xin-Yu; Li; Hong; Zhang; Gui-Gang; Li

    2014-01-01

    AIM:To investigate the effect of amniotic membrane covering(AMC) on the healing of cornea epithelium and visual acuity for fungal keratitis after debridement.METHODS:Twenty fungal keratitis patients were divided into two groups randomly, the AMC group and the control group, ten patients each group. Both debridement of the infected cornea tissue and standard anti-fungus drugs treatments were given to every patients, monolayer amniotic membrane were sutured to the surface of the entire cornea and bulbar conjunctiva with 10-0 nylon suture for patients in the AMC group.The diameter of the ulcer was determined with slit lamp microscope and the depth of the infiltration was determined with anterior segment optical coherence tomography. Uncorrected visual acuity(UCVA) was tested before surgery and three month after healing of the epithelial layer. The healing time of the cornea epithelium, visual acuity(VA) was compared between the two groups using t- test.RESULTS:There was no statistical difference of the diameter of the ulcer, depth of the infiltration, height of the hypopyon and VA between the two groups beforesurgery(P >0.05). The average healing time of the AMC group was 6.89 ±2.98 d, which was statistically shorter than that of the control group(10.23±2.78d)(P <0.05).The average UCVA of the AMC group was 0.138 ±0.083,which was statistically better than that of the control group(0.053±0.068)(P <0.05).CONCLUSION:AMC surgery could promote healing of cornea epithelium after debridement for fungal keratitis and lead to better VA outcome.

  20. Observers' Judgments of the Effects of Glare on Their Visual Acuity for High and Low Contrast Stimuli.

    Science.gov (United States)

    Sewall, Ashley A Stafford; Borzendowski, Stephanie A Whetsel; Tyrrell, Richard A; Stephens, Benjamin R; Rosopa, Patrick J

    2016-07-01

    Disability glare refers to a reduction in the ability to discern a stimulus that is positioned near another stimulus that has a much higher luminance. While it is common for drivers to report that they have been "blinded" by oncoming headlights, it is unclear whether observers can accurately judge when they are visually disabled by glare. This experiment sought to quantify the accuracy with which observers can judge when a glare source reduces their visual acuity. Seventeen observers estimated their disability glare threshold (DGT)-the luminance of a glare source that would be just sufficient to impair their ability to discern the orientation of a Landolt C that was surrounded by the glare source. These estimated DGTs were compared to the participant's actual DGTs. Participants consistently underestimated the intensity of glare that was required to impair their acuity. On average, estimates of glare threshold were 88% lower than actual glare threshold intensities. Participants' judgments were affected by stimulus size but not stimulus contrast. These results suggest that observers can exaggerate the debilitating effects of glare and that they can fail to appreciate that high contrast stimuli are more robust to glare. A driver who believes that even the lowest intensities of headlight glare can visually impair an oncoming driver may be reluctant to use high beam headlamps, despite their significant visibility advantages.

  1. Effect of air and sulfur hexafluoride (SF6) tamponade on visual acuity after epiretinal membrane surgery: a pilot study.

    Science.gov (United States)

    Chabot, Guillaume; Bourgault, Serge; Cinq-Mars, Benoit; Tourville, Éric; Caissie, Mathieu

    2017-06-01

    The aim of this study was to compare visual acuity improvement after epiretinal membrane (ERM) surgery using air and sulfur hexafluoride (SF6) tamponade. Secondary objectives were to evaluate Visual Function Questionnaire (VFQ) scores and central retinal thickness (CRT) changes. This was a prospective, randomized study. Thirty-two patients were prospectively randomized, 19 to the air group and 13 to the SF6 group. This study has enrolled patients with ERM from clinical practice of 4 vitreoretinal surgeons. Preoperative and postoperative data included best-corrected visual acuity (BCVA) with the use of the Early Treatment Diabetic Retinopathy Study (ETDRS) chart, VFQ scores, CRT, and cataract staging. Pars plana vitrectomy with ERM peeling was performed on all patients, either with partial air tamponade or with complete SF6 tamponade. Mean BCVA improved by 0.07 logMAR (3.5 ETDRS letters) in the air group and by 0.09 logMAR (4.5 ETDRS letters) in the SF6 group (p = 0.58). There was no statistically significant difference between the groups with regard to BCVA, VFQ scores, and CRT. The groups had similar rates of cataract progression and adverse events. ERM peeling with partial air tamponade or with complete SF6 tamponade have similar outcomes in terms of BCVA, VFQ scores, CRT, cataract development, and adverse events. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

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

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    Venkataratnam

    2015-10-01

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

  3. Zagreb Amblyopia Preschool Screening Study: near and distance visual acuity testing increase the diagnostic accuracy of screening for amblyopia

    OpenAIRE

    Bušić, Mladen; Bjeloš, Mirjana; Petrovečki, Mladen; Kuzmanović Elabjer, Biljana; Bosnar, Damir; Ramić, Senad; Miletić, Daliborka; Andrijašević, Lidija; Kondža Krstonijević, Edita; Jakovljević, Vid; Bišćan Tvrdi, Ana; Predović, Jurica; Kokot, Antonio; Bišćan, Filip; Kovačević Ljubić, Mirna

    2016-01-01

    Aim To present and evaluate a new screening protocol for amblyopia in preschool children. Methods Zagreb Amblyopia Preschool Screening (ZAPS) study protocol performed screening for amblyopia by near and distance visual acuity (VA) testing of 15 648 children aged 48-54 months attending kindergartens in the City of Zagreb County between September 2011 and June 2014 using Lea Symbols in lines test. If VA in either eye was >0.1 logMAR, the child was re-tested, if failed at re-test, the child was ...

  4. Effect of hemodialysis on visual acuity, intraocular pressure, and macular thickness in patients with chronic kidney disease

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    Chelala E

    2015-01-01

    Full Text Available Elias Chelala,1,2,* Ali Dirani,1,2,* Ali Fadlallah,1,2 Elise Slim,1,2 Youssef Abdelmassih,1,2 Henry Fakhoury,3 Patrick Baz,1,2 Riad Bejjani1,2 1Faculty of Medicine, Saint-Joseph University, 2Hôtel-Dieu de France Hospital, Saint-Joseph University, 3Eye and Ear Hospital, Beirut, Lebanon *These two authors contributed equally to this work Background: The aim of this study was to evaluate the effects of hemodialysis (HD on visual acuity, intraocular pressure (IOP, and central foveal thickness (CFT in patients with chronic kidney disease.Materials and methods: Forty-nine eyes from 49 chronic kidney-disease patients were analyzed. Causes of chronic kidney disease included diabetes mellitus (n=9 patients, hypertensive nephrosclerosis (n=15 patients, and other causes (n=25 patients. All patients underwent HD in the Dialysis Unit of Hôtel-Dieu de France Hospital. Best-corrected visual acuity, CFT, and IOP were evaluated before and after HD. CFT was measured with spectral domain optical coherence tomography, and IOP was measured with Goldmann applanation tonometry.Results: Neither decimal best-corrected visual acuity (pre-HD 0.71±0.32, post-HD 0.72±0.31; P=0.877 nor CFT (pre-HD 251.39±39.29, post-HD 253.09±39.26; P=0.272 significantly changed after HD. However, mean IOP significantly decreased from 13.99±2.48 before HD to 12.65±2.41 mmHg after HD (P=0.001. IOP change was significantly correlated with serum albumin levels (P=0.008 and weight changes (P=0.047.Conclusion: HD can affect various ocular parameters. This is particularly true of IOP, which decreases significantly following HD. Keywords: chronic kidney disease, hemodialysis, visual acuity, central macular thickness, intraocular pressure

  5. Reproducibility of Nigh Vision Goggle Visual Acuity Measurements Using Landolt C’s

    Science.gov (United States)

    1999-12-08

    Task, 1979), Snellen Acuity (Bailey & Lovie, 1979; Wiley, 1989; Miller, Provines, Block & Tredici, 1984), square-wave targets (Task & Genco , 1986...the observer focused the corresponding objective lens by viewing the 3 x 3A, NVG high- contrast square-wave resolution chart (Task & Genco , 1986...for television displays. Technical Report No. AMRL-TR-79-7. NTIS: Alexandria VA. Task, H. L. and Genco , L. V. (1986). Contrast sensitivity function

  6. Higher Cognitive Function in Elderly Individuals with Previous Cataract Surgery: Cross-Sectional Association Independent of Visual Acuity in the HEIJO-KYO Cohort.

    Science.gov (United States)

    Miyata, Kimie; Obayashi, Kenji; Saeki, Keigo; Tone, Nobuhiro; Tanaka, Kunihiko; Nishi, Tomo; Morikawa, Masayuki; Kurumatani, Norio; Ogata, Nahoko

    2016-06-01

    Cataract surgery improves visual acuity and drastically increases the capacity for light reception to the retina. Although previous studies suggested that both light exposure and visual acuity were associated with cognitive function, the relationships between cataract surgery, visual acuity, and cognitive function have not been evaluated in large populations. In this cross-sectional study, we measured cognitive function using the Mini-Mental State Examination and best-corrected visual acuity in pseudophakic (previous cataract surgery) and phakic (no previous cataract surgery) elderly individuals. Of 945 participants (mean age 71.7 years), 166 (17.6%) had pseudophakia and 317 (33.5%) had impaired cognitive function (score ≤26). The pseudophakic group showed significantly better visual acuity than the phakic group (p = 0.003) and lower age-adjusted odds ratio (ORs) for cognitive impairment (OR 0.66; p = 0.038). Consistently, in multivariate logistic regression models, after adjusting for confounding factors, including visual acuity and socioeconomic status, ORs for cognitive impairment were significantly lower in the pseudophakic group than in the phakic group (OR 0.64; 95% confidence interval 0.43-0.96; p = 0.031). This association remained significant in sensitivity analysis, excluding participants with low cognitive score ≤23 (n = 36). In conclusion, in a general elderly population, prevalence of cognitive impairment was significantly lower in pseudophakic individuals independently of visual acuity. The association was also independent of several major causes of cognitive impairment such as aging, gender, obesity, socioeconomic status, hypertension, diabetes, sleep disturbances, depressive symptoms, and physical inactivity.

  7. Relationship between Body Mass Index, Blood Pressure, and Visual Acuity in Residents of Esan West Local Government Area of Edo State, Nigeria

    Directory of Open Access Journals (Sweden)

    I. O. Ernest-Nwoke

    2014-01-01

    Full Text Available Aim. To study the relationship between body mass index (BMI and blood pressure (BP on visual acuity among apparently healthy residents of Ekpoma, Esan West Local Government Area of Edo State, Nigeria. Methodology. This is a cross-sectional descriptive study among 225 subjects (ages of 18–35 years from whom BP, body weight, and height were collected. Visual acuity was measured using the Snellen chart following standard procedures of number of letters seen at 6-metre distance. The data were then analyzed using SPSS version 17. Results. The sampled population consists of 112 male and 113 female (mean age 31.72±14.2 years. Majority (180 of the respondents had normal visual acuity. However, compared with the respondents with normal BMI (R19.61±1.5; L19.67±1.70, visual acuity of underweight (R18.53±2.30; L18.53±2.70 and obese (R15.68±4.79; L17.73±1.70 were more deviated. Similarly, compared with respondent with normal BP (120–125/80–85 mmHg; R18.00±2.53; L18.07±3.11, hypotensive (R15.5±7.35; L15.00±10.20, and hypertensive (R15.01±21.25; L15.00±11.91 respondents had deviated visual acuity. Conclusion. Abnormal body weight (underweight and obese and BP (hypotension and hypertension have potential negative impacts on visual acuity. Based on the observed relationship between weights, BP, and visual acuity, eye examinations can be included as regular screening exercise for abnormal BMI and BP conditions.

  8. Visual stimulus parameters seriously compromise the measurement of approximate number system acuity and comparative effects between adults and children

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    Denes eSzucs

    2013-07-01

    Full Text Available It has been suggested that a simple non-symbolic magnitude comparison task is sufficient to measure the acuity of a putative Approximate Number System (ANS. A proposed measure of the ANS, the so-called 'internal Weber fraction' (w, would provide a clear measure of ANS acuity. However, ANS studies have never presented adequate evidence that the visual stimulus parameters did not compromise measurements of w to such extent that w is actually driven by visual instead of numerical processes. We therefore investigated this question by testing non-symbolic magnitude discrimination in seven-year-old children and adults. We controlled for visual parameters in a more stringent manner than usual. As a consequence of these controls, in some trials numerical cues correlated positively with number while in others they correlated negatively with number. This congruency effect strongly correlated with w, which means that congruency effects were probably driving effects in w. Consequently, in both adults and children congruency had a major impact on the fit of the model underlying the computation of w. Furthermore, children showed larger congruency effects than adults. This suggests that ANS tasks are seriously compromised by the visual stimulus parameters, which cannot be controlled. Hence, they are not pure measures of the ANS and some putative w or ratio effect differences between children and adults in previous ANS studies may be due to the differential influence of the visual stimulus parameters in children and adults. In addition, because the resolution of congruency effects relies on inhibitory (interference suppression function, some previous ANS findings were probably influenced by the developmental state of inhibitory processes especially when comparing children with developmental dyscalculia and typically developing children.

  9. Interocular Shift of Visual Attention Enhances Stereopsis and Visual Acuities of Anisometropic Amblyopes beyond the Critical Period of Visual Development: A Novel Approach

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    Liwen Huang

    2014-01-01

    Full Text Available Aims. Increasing evidence shows that imbalanced suppressive drive prior to binocular combination may be the key factor in amblyopia. We described a novel binocular approach, interocular shift of visual attention (ISVA, for treatment of amblyopia in adult patients. Methods. Visual stimuli were presented anaglyphically on a computer screen. A square target resembling Landolt C had 2 openings, one in red and one in cyan color. Through blue-red goggles, each eye could only see one of the two openings. The patient was required to report the location of the opening presented to the amblyopic eye. It started at an opening size of 800 sec of arc, went up and down in 160 sec of arc step, and stopped when reaching the 5th reversals. Ten patients with anisometropic amblyopia older than age 14 (average age: 26.7 were recruited and received ISVA treatment for 6 weeks, with 2 training sessions per day. Results. Both Titmus stereopsis (z=-2.809, P=0.005 and Random-dot stereopsis (z=-2.317, P=0.018 were significantly improved. Average improvement in best corrected visual acuity (BCVA was 0.74 line (t=5.842, P<0.001. Conclusions. The ISVA treatment may be effective in treating amblyopia and restoring stereoscopic function.

  10. Modeling peripheral visual acuity enables discovery of gaze strategies at multiple time scales during natural scene search

    Science.gov (United States)

    Ramkumar, Pavan; Fernandes, Hugo; Kording, Konrad; Segraves, Mark

    2015-01-01

    Like humans, monkeys make saccades nearly three times a second. To understand the factors guiding this frequent decision, computational models of vision attempt to predict fixation locations using bottom-up visual features and top-down goals. How do the relative influences of these factors evolve over multiple time scales? Here we analyzed visual features at fixations using a retinal transform that provides realistic visual acuity by suitably degrading visual information in the periphery. In a task in which monkeys searched for a Gabor target in natural scenes, we characterized the relative importance of bottom-up and task-relevant influences by decoding fixated from nonfixated image patches based on visual features. At fast time scales, we found that search strategies can vary over the course of a single trial, with locations of higher saliency, target-similarity, edge–energy, and orientedness looked at later on in the trial. At slow time scales, we found that search strategies can be refined over several weeks of practice, and the influence of target orientation was significant only in the latter of two search tasks. Critically, these results were not observed without applying the retinal transform. Our results suggest that saccade-guidance strategies become apparent only when models take into account degraded visual representation in the periphery. PMID:25814545

  11. Comparison of visual acuity in macular degeneration patients measured with snellen and early treatment diabetic retinopathy study charts.

    Science.gov (United States)

    Falkenstein, Iryna A; Cochran, Denine E; Azen, Stanley P; Dustin, Laurie; Tammewar, Ajay M; Kozak, Igor; Freeman, William R

    2008-02-01

    To compare the measurements of visual acuity (VA) results measured with Snellen and Early Treatment Diabetic Retinopathy Study (ETDRS) charts in eyes with and without age-related macular degeneration (AMD). Cross-sectional study. One hundred four participants (190 eyes) selected from a university retina practice; 80 participants (142 eyes) had some degree of AMD. Visual acuity was measured in each patient using standard procedure with both Snellen and ETDRS charts in random order. Statistical analysis of the results was performed. Difference in VA measured by both charts in logarithm of minimal angle of resolution (logMAR) notations. Overall, the mean Snellen VA was 0.78 logMAR (= 20/120), and the mean ETDRS VA in the same eye was 0.54 logMAR (= 20/70; P20/30). On average, 20/200 on Snellen was 20/95 on ETDRS (>3 lines difference), and 20/30 on Snellen was 20/25 on ETDRS (Snellen and ETDRS charts, and it was more pronounced in the group with poor vision. The ETDRS measurements yielded better VA, particularly in participants with vision Snellen charts) with outcomes from clinical trials (which typically measure VA using ETDRS charts).

  12. Impact of positive coupling of the eye's trefoil and coma in retinal image quality and visual acuity.

    Science.gov (United States)

    Villegas, Eloy A; Alcón, Encarna; Artal, Pablo

    2012-08-01

    When the eye's higher-order aberrations are measured and reported, as important as the magnitude of each individual term are the possible combinations between them, which may change the overall retinal image quality and therefore visual performance. We have evaluated the relationships among different aberration terms in the human eye-coma, trefoil, and spherical aberration-and their effects on both retinal image quality and visual acuity (VA). In a group of normal young subjects with normal to excellent vision, we measured the eye's aberrations and high contrast VA under natural conditions after carefully correcting defocus and astigmatism. Among the different combinations of aberration terms, we only found a significant negative correlation (r2=0.30) between the vertical coefficients of trefoil C(3,-3) and coma C(3,-1). This is a positive coupling that produces a better retinal image quality than any of the other possible combinations of these terms. However, this improvement in image quality is limited by the presence of other aberrations. Only in a few eyes that presented the larger values of coupled vertical trefoil and coma appeared a significant improvement of image quality. Although we did not find a clear correction between the coma-trefoil vertical coupling and VA, most eyes with large amounts of aberrations (RMS>0.4 μm) have these terms coupled, keeping decimal acuity around 1.2 or higher.

  13. A pilot trial of the iPad tablet computer as a portable device for visual acuity testing.

    Science.gov (United States)

    Zhang, Zhao-tian; Zhang, Shao-chong; Huang, Xiong-gao; Liang, Ling-yi

    2013-01-01

    We evaluated the accuracy of an app for the iPad tablet computer (Eye Chart Pro) as a portable method of visual acuity (VA) testing. A total of 120 consecutive patients (240 eyes) underwent visual acuity test with an iPad 2 and a conventional light-box chart. The logMAR VA results from the iPad were significantly higher than those from the light-box (P iPad chart and the light-box chart, with 95% limits of agreement of -0.14 to 0.19. Two groups of patients were defined: in Group 1 there were 182 eyes with VA better than 0.1 according to the light-box VA test. The median logMAR VA by the iPad was 0.54 and by the light-box chart it was 0.52; there was no significant difference between them (P = 0.69). In Group 2 there were 58 eyes with VA equal to or worse than 0.1 according to the light-box VA test. The median logMAR VA by the iPad was 1.26 and was 1.10 by the light box; the result from the iPad was significantly lower (P iPad is reliable for VA testing only when the Snellen VA is better than 0.1 (20/200).

  14. Monocular indoor localization techniques for smartphones

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    Hollósi Gergely

    2016-12-01

    Full Text Available In the last decade huge research work has been put to the indoor visual localization of personal smartphones. Considering the available sensor capabilities monocular odometry provides promising solution, even reecting requirements of augmented reality applications. This paper is aimed to give an overview of state-of-the-art results regarding monocular visual localization. For this purpose essential basics of computer vision are presented and the most promising solutions are reviewed.

  15. Are individual differences in reading speed related to extrafoveal visual acuity and crowding?

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    Romy Frömer

    Full Text Available Readers differ considerably in their speed of self-paced reading. One factor known to influence fixation durations in reading is the preprocessing of words in parafoveal vision. Here we investigated whether individual differences in reading speed or the amount of information extracted from upcoming words (the preview benefit can be explained by basic differences in extrafoveal vision--i.e., the ability to recognize peripheral letters with or without the presence of flanking letters. Forty participants were given an adaptive test to determine their eccentricity thresholds for the identification of letters presented either in isolation (extrafoveal acuity or flanked by other letters (crowded letter recognition. In a separate eye-tracking experiment, the same participants read lists of words from left to right, while the preview of the upcoming words was manipulated with the gaze-contingent moving window technique. Relationships between dependent measures were analyzed on the observational level and with linear mixed models. We obtained highly reliable estimates both for extrafoveal letter identification (acuity and crowding and measures of reading speed (overall reading speed, size of preview benefit. Reading speed was higher in participants with larger uncrowded windows. However, the strength of this relationship was moderate and it was only observed if other sources of variance in reading speed (e.g., the occurrence of regressive saccades were eliminated. Moreover, the size of the preview benefit--an important factor in normal reading--was larger in participants with better extrafoveal acuity. Together, these results indicate a significant albeit moderate contribution of extrafoveal vision to individual differences in reading speed.

  16. Effect of magnetic resonance imaging on near visual acuity Efecto de la resonancia magnética sobre la agudeza visual cercana

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    José David Paulo Trujillo

    2007-08-01

    Full Text Available Purpose: To determine the variation of near visual acuity, in patients exposed during short periods to intense magnetic fields in studies of magnetic resonance imaging. Methods: Descriptive study of a case series that included 40 healthy and literate individuals older than 40 years, nine of them men, submitted to a procedure of head and neck magnetic resonance imaging; all of them had near visual acuity better than 20/200 without glasses, and were not under the effects of ansiolytic medications. Near vision was measured with the Jaeger chart before and immediately after the RM imaging procedure. Measurements were carried out by two different observers; every one of them did not know the results obtained by the other. Results: Means for near vision acuity before and after the magnetic resonance imaging procedure were, respectively, 1.4324 ± 0.4766 m and 1.4375 ± 0.5024 m (p = 0.505. Conclusions: In the evaluated group, no statistically significant change was observed in near vision acuity after head and neck magnetic resonance imaging procedures. Objetivos: determinar la variación de la agudeza visual cercana en pacientes expuestos a campos magnéticos intensos por períodos cortos en estudios de resonancia magnética. Métodos: estudio descriptivo de una serie de casos, que incluyó 9 hombres y 31 mujeres alfabetas mayores de 40 años; debían tener una agudeza visual mejor de 20/200 y no estar bajo los efectos de medicamentos ansiolíticos. Estas personas fueron sometidas a procedimientos diagnósticos de resonancia magnética de cabeza y cuello; antes del procedimiento e inmediatamente después de terminarlo se les midió la agudeza visual (AV con la carta de visión cercana de Jaeger. Las mediciones fueron llevadas a cabo por dos observadores diferentes, cada uno de los cuales desconocía los resultados obtenidos por el otro. Resultados: las medias de la agudeza visual cercana antes y después de la resonancia magnética fueron

  17. A phytochemical-rich diet may explain the absence of age-related decline in visual acuity of Amazonian hunter-gatherers in Ecuador.

    Science.gov (United States)

    London, Douglas S; Beezhold, Bonnie

    2015-02-01

    Myopia is absent in undisturbed hunter-gatherers but ubiquitous in modern populations. The link between dietary phytochemicals and eye health is well established, although transition away from a wild diet has reduced phytochemical variety. We hypothesized that when larger quantities and greater variety of wild, seasonal phytochemicals are consumed in a food system, there will be a reduced prevalence of degenerative-based eye disease as measured by visual acuity. We compared food systems and visual acuity across isolated Amazonian Kawymeno Waorani hunter-gatherers and neighboring Kichwa subsistence agrarians, using dietary surveys, dietary pattern observation, and Snellen Illiterate E visual acuity examinations. Hunter-gatherers consumed more food species (130 vs. 63) and more wild plants (80 vs. 4) including 76 wild fruits, thereby obtaining larger variety and quantity of phytochemicals than agrarians. Visual acuity was inversely related to age only in agrarians (r = -.846, P .05). This unusual absence of juvenile-onset vision problems may be related to local, organic, whole food diets of subsistence food systems isolated from modern food production. Our results suggest that intake of a wider variety of plant foods supplying necessary phytochemicals for eye health may help maintain visual acuity and prevent degenerative eye conditions as humans age.

  18. Comparison of contrast sensitivity and visual acuity between deep anterior lamellar keratoplasty and penetrating keratoplasty in patients with keratoconus

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    Mehmet Orcun Akdemir

    2012-12-01

    Full Text Available AIM: To evaluate postoperative visual acuity and contrast sensitivity results following deep anterior lamellar keratoplasty (DALK and penetrating keratoplasty (PK in patients with keratoconus (KC. METHODS: All the patients’ records with KC who had PK or DALK surgery between May 2010 and May 2011 were retrospectively reviewed. Sixty patients who underwent successful corneal transplantation for KC: 30 eyes underwent DALK and 30 eyes underwent PK were included in this study. Preoperative and postoperative mean logarithm of the minimum angle of resolution (logMAR uncorrected visual acuity (UCVA, logMAR best spectacle-corrected visual acuity (BSCVA and intraocular pressure (IOP were evaluated. Contrast sensitivity tests (CS were done preoperative and 2 months after all sutures had removed. All surgeries were performed under regional anesthesia (retrobulbar anesthesia by 1 surgeon (B.K. who was experienced in penetrating and lamellar keratoplasty techniques.RESULTS: The mean age of the DALK group was 29.67±4.95 (range 18-40 years and the PK group was 28.7±3.53 (range 18-39 years. Preoperatively there was no significant difference in the logMAR UCVA, logMAR BSCVA and IOP between the DALK (1.281±0.56; 0.97±0.85; 12.07±2.12mmHg and PK (1.34±0.21; 0.98±0.21; 13±2.12mmHg groups. One-year after surgery there was no significant difference in the mean logMAR UCVA and IOP between the DALK (0.46±0.37; 11.73±2.1mmHg and PK (0.38±0.21; 12±2.12mmHg groups. The mean contrast sensitivity was evaluated by CC-100 Topcon LCD at 1.5, 2.52, 4.23, 7.10 and 11.91 cycles per degree (cs/deg spatial frequencies before and 2 months after the all sutures had removed. CONCLUSION: All patients with keratoconus in both DALK and PK groups performed good visual function postoperatively. The mean contrast sensitivity increased considerably at all spatial frequencies compared with preoperative levels in the DALK and PK groups. The mean post-operative evaluation of

  19. Reduced responsiveness to long-term monocular deprivation of parvalbumin neurons assessed by c-Fos staining in rat visual cortex.

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    Marco Mainardi

    Full Text Available BACKGROUND: It is generally assumed that visual cortical cells homogeneously shift their ocular dominance (OD in response to monocular deprivation (MD, however little experimental evidence directly supports this notion. By using immunohistochemistry for the activity-dependent markers c-Fos and Arc, coupled with staining for markers of inhibitory cortical sub-populations, we studied whether long-term MD initiated at P21 differentially affects visual response of inhibitory neurons in rat binocular primary visual cortex. METHODOLOGY/PRINCIPAL FINDINGS: The inhibitory markers GAD67, parvalbumin (PV, calbindin (CB and calretinin (CR were used. Visually activated Arc did not colocalize with PV and was discarded from further studies. MD decreased visually induced c-Fos activation in GAD67 and CR positive neurons. The CB population responded to MD with a decrease of CB expression, while PV cells did not show any effect of MD on c-Fos expression. The persistence of c-Fos expression induced by deprived eye stimulation in PV cells is not likely to be due to a particularly low threshold for activity-dependent c-Fos induction. Indeed, c-Fos induction by increasing concentrations of the GABAA antagonist picrotoxin in visual cortical slices was similar between PV cells and the other cortical neurons. CONCLUSION: These data indicate that PV cells are particularly refractory to MD, suggesting that different cortical subpopulation may show different response to MD.

  20. Uncorrected visual acuity in the immediate postoperative period following uncomplicated cataract surgery: bimanual microincision cataract surgery versus standard coaxial phacoemulsification.

    LENUS (Irish Health Repository)

    Saeed, Ayman

    2012-02-01

    AIM: We compared bimanual microincision cataract surgery (MICS) and standard coaxial phacoemulsification (CAP) in terms of uncorrected visual acuity (UCVA) recorded 1 h and 2 weeks postoperatively. METHODS: This was a prospective, nonrandomised comparative study. All MICS procedures were performed by one surgeon (MGM), and all CAP procedures were performed by another surgeon (SB). Eyes with visually consequential ocular morbidity were excluded. The primary outcome measure was UCVA recorded 1 h postoperatively. RESULTS: One hundred eyes underwent MICS and CAP (50 eyes in each group). The treatment groups did not differ significantly in terms of preoperative mean best corrected visual acuity (6\\/24 +\\/- 4.3 lines and 6\\/20 +\\/- 4.4 lines in the MICS and the CAP groups, respectively; P = 0.65). Also, there was no significant difference in terms of postoperative UCVA at 1 h or at 2 weeks (mean +\\/- standard deviation UCVA 1 h postoperatively: MICS: 6\\/36 +\\/- 5.7 lines; CAP: 6\\/30 +\\/- 4.7 lines; P = 0.80; UCVA 2 weeks postoperatively: MICS: 6\\/10 +\\/- 1.9 lines; CAP: 6\\/10 +\\/- 2.2 lines; P = 0.90). However, nine eyes (18%) and one eye (2%) achieved a UCVA of C6\\/12 at 1 h following MICS and CAP, respectively, and this difference was statistically significant (P = 0.02). CONCLUSION: Mean UCVA at 1 h and at 2 weeks following cataract surgery was not significantly different between eyes undergoing MICS and CAP. However, a greater proportion of patients achieved a UCVA of C6\\/12 following MICS when compared with CAP.

  1. Visual Acuity Testing Using Autorefraction or Pinhole Occluder as Compared with a Manual Protocol Refraction in Individuals with Diabetes

    Science.gov (United States)

    Sun, Jennifer K.; Aiello, Lloyd Paul; Cavallerano, Jerry D.; Stockman, Margaret; Miller, Kellee M.; Qin, Haijing; Beck, Roy W.; Glassman, Adam R.

    2010-01-01

    Purpose To compare visual acuity (VA) scores obtained after autorefraction or using a pinhole occluder to scores obtained after refraction according to a standard clinical research protocol. Design Prospective, comparative case series Participants One hundred and ten study participants (209 eyes) with diabetes mellitus and a broad range of diabetic retinopathy severity and visual acuity (VA). Methods VA was measured after autorefraction by a Topcon KR-8000 autorefractor as well as after a Diabetic Retinopathy Clinical Research Network (DRCR.net) protocol manual refraction. The order of testing was randomized and examiners were masked to the source of each refraction. A second VA measurement, utilizing an identical DRCR.net manual refraction, was made in a subset of eyes (N = 144, 69%) in order to establish test-retest variability for comparison purposes. All eyes underwent VA testing using a pinhole occluder. Main Outcome Measures Best corrected VA as measured by the Electronic Early Treatment Diabetic Retinopathy Study Visual Acuity Test© (E-ETDRS). Results In all eyes, the median E-ETDRS VA letter score (EVA) obtained after manual refraction (MR-EVA) was 69 (Snellen equivalent 20/40), ranging from 4 to 93 (20/800 to 20/16). The median MR-EVA was slightly better than the median EVA obtained after autorefraction (AR-EVA), with a median difference (AR-EVA – MR-EVA) of −1 letter (25th, 75th percentiles: −4, 2 letters). The absolute difference between AR-EVA and MR-EVA was similar to the test-retest variability of MR-EVA alone. In contrast, MR-EVA was better than EVA obtained using a pinhole occluder (PH-EVA), (median PH-EVA – MR-EVA: −4 letters [−9, 0]), and had significantly less test-retest variability (Prefraction (median difference: +0.25 Diopters [0, +0.63 Diopters]). Conclusions Given the substantial time and effort required for training and certification of study protocol refractionists, and the similarity between AR-EVA and MR-EVA, further

  2. Influence of adaptive-optics ocular aberration correction on visual acuity at different luminances and contrast polarities.

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    Marcos, Susana; Sawides, Lucie; Gambra, Enrique; Dorronsoro, Carlos

    2008-10-06

    We evaluated the visual benefit of correcting astigmatism and high-order aberrations with adaptive optics (AO) on visual acuity (VA) measured at 7 different luminances (ranging from 0.8 to 50 cd/m(2)) and two contrast polarities (black letters on white background, BoW, and white letters on black background, WoB) on 7 subjects. For the BoW condition, VA increased with background luminance in both natural and AO-corrected conditions, and there was a benefit of AO correction at all luminances (by a factor of 1.29 on average across luminances). For WoB VA increased with foreground luminance but decreased for the highest luminances. In this reversed polarity condition AO correction increased VA by a factor of 1.13 on average and did not produce a visual benefit at high luminances. The improvement of VA (averaged across conditions) was significantly correlated (p = 0.04) with the amount of corrected aberrations (in terms of Strehl ratio). The improved performance with WoB targets with respect to BoW targets is decreased when correcting aberrations, suggesting a role of ocular aberrations in the differences in visual performance between contrast polarities.

  3. Monocular deprivation delays the dynamic changes of phosphorylated synapsin Ia/b at site-1 in contralateral visual cortex of juvenile mice.

    Science.gov (United States)

    Fu, Tao; Su, Qing; Xi, Ping; Han, Song; Li, Junfa

    2015-03-01

    Synapsins as a family of presynaptic terminal phosphoprotein participates in neuronal development, but their role in the synaptic plasticity of visual cortex is unclear. In this study, the impact of monocular deprivation (MD) on dynamic changes of isoform-specific protein expression and site 1 phosphorylation of synapsins in visual cortex of the postnatal mice were observed by using the technique of Western blot analysis. The results showed that the total (T-) protein levels of synapsins including the isoform of Ia/b, IIa/b and IIIa were about 21-26% of adult level in visual cortex of mice at postnatal 7 days (P7), and then the T-synapsin Ia/b and IIb could quickly reach adult level at P35. However, the T-synapsin IIa and IIIa increased more slowly (71-74% at P35), and then kept increasing in the visual cortex of mice at P60. Unlike to the changes of T-synapsins, the level of phosphorylated (P-) synapsin Ia/b (not IIa/b and IIIa) at site 1 increased with development to the highest level at P21, and then decreased rapidly to a low level in visual cortex of mice at P35-60. In addition, we found that the levels of P-synapsin Ia/b increased significantly in left visual cortex of P28 and P35 (not P21 and P42) mice with 1-week MD of right eye; and no significant changes of T-synapsins were observed in both left and right sides of visual cortex in P21-42 mice with MD treatment. These results suggested that the isoform-specific protein expression and site-1 phosphorylation of synapsins might play a different role in the synaptic plasticity of visual cortex, and MD delays the dynamic changes of phosphorylated synapsin Ia/b at site-1 in contralateral visual cortex of juvenile mice.

  4. Idiopathic macular hole: post-operative morpho-functional assessment and prognostic factors for recovery of visual acuity

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    Flavio Tirelli

    2013-09-01

    Full Text Available INTRODUCTION: Idiopathic macular hole (MH is a full-thickness retinal damage typical of the advanced age with a high social impact because, as it affects the macula, it produces severe loss of vision. AIM: This study aims to evaluate the therapeutic efficacy of surgery and to determine prognostic factors, considering how hypovision weighs on individual quality of life and on public health. METHODS: All patients affected by MH were evaluated with an ophthalmic visit, measurement of visual acuity and Optical Coherence Tomography (OCT documentation before surgical intervention. Surgical treatment followed and, subsequently, all the patients were examined with the same documentation at 7 days, 1 month, 3 months, 6 months and 12 months. RESULTS: Surgical therapy, with the modern techniques available, demonstrated the efficacy of anatomical recovery and retinal function. Furthermore, the quantitative characteristics of the MH in the OCT scanning revealed an important prognostic function.

  5. Global motion perception is independent from contrast sensitivity for coherent motion direction discrimination and visual acuity in 4.5-year-old children.

    Science.gov (United States)

    Chakraborty, Arijit; Anstice, Nicola S; Jacobs, Robert J; Paudel, Nabin; LaGasse, Linda L; Lester, Barry M; Wouldes, Trecia A; Harding, Jane E; Thompson, Benjamin

    2015-10-01

    Global motion processing depends on a network of brain regions that includes extrastriate area V5 in the dorsal visual stream. For this reason, psychophysical measures of global motion perception have been used to provide a behavioral measure of dorsal stream function. This approach assumes that global motion is relatively independent of visual functions that arise earlier in the visual processing hierarchy such as contrast sensitivity and visual acuity. We tested this assumption by assessing the relationships between global motion perception, contrast sensitivity for coherent motion direction discrimination (henceforth referred to as contrast sensitivity) and habitual visual acuity in a large group of 4.5-year-old children (n=117). The children were born at risk of abnormal neurodevelopment because of prenatal drug exposure or risk factors for neonatal hypoglycemia. Motion coherence thresholds, a measure of global motion perception, were assessed using random dot kinematograms. The contrast of the stimuli was fixed at 100% and coherence was varied. Contrast sensitivity was measured using the same stimuli by fixing motion coherence at 100% and varying dot contrast. Stereoacuity was also measured. Motion coherence thresholds were not correlated with contrast sensitivity or visual acuity. However, lower (better) motion coherence thresholds were correlated with finer stereoacuity (ρ=0.38, p=0.004). Contrast sensitivity and visual acuity were also correlated (ρ=-0.26, p=0.004) with each other. These results indicate that global motion perception for high contrast stimuli is independent of contrast sensitivity and visual acuity and can be used to assess motion integration mechanisms in children.

  6. Relations of low contrast visual acuity, quality of life and multiple sclerosis functional composite: a cross-sectional analysis.

    Science.gov (United States)

    Schinzel, Johann; Zimmermann, Hanna; Paul, Friedemann; Ruprecht, Klemens; Hahn, Katrin; Brandt, Alexander U; Dörr, Jan

    2014-02-20

    Although common and often disabling in multiple sclerosis (MS), visual dysfunction is currently not adequately accounted for in both clinical routine and MS trials. Sloan low contrast letter acuity (SLCLA) is a standardised chart-based measure of visual function particular at low contrast and has been suggested as additional visual component to the Multiple Sclerosis Functional Composite (MSFC). Here, we evaluate the relations between SLCLA, retinal integrity, MSFC, and quality of life (QoL) in MS patients. Cross-sectional analysis of retinal nerve fibre layer (RNFL) thickness, MSFC, SLCLA (2.5% and 1.25% contrast levels), visual evoked potentials, and QoL (Short Form (SF) 36, National Eye Institute Visual Functioning Questionnaire (NEIVFQ)) using baseline data of 92 MS patients from an ongoing prospective longitudinal trial. Relations between RNFL thickness or P100 latency and SLCLA were analysed using generalised estimating equations (GEE) accounting for intra-individual inter-eye dependencies and corrected for age, gender, and history of optic neuritis. Pearson's correlations were used to assess relations between SLCLA, MSFC, and QoL. SLCLA reflected RNFL thickness (p = 0.021) and P100 latency (p = 0.004) and predicted vision-related QoL, reflected by the NEIVFQ39 subscores "general vision" and "near activities" (p QoL reflected by SF36. Implementing SLCLA into MSFC, thus creating a four-dimensional MSFC4, captured aspects of disability reflected by the NEIVFQ39 subscores "general vision" (r = 0.42, p QoL in MS. More importantly, using a prospective cross-sectional approach we provide evidence that extending the MSFC by SLCLA as an additional visual component increases the performance of MSFC to capture MS-related disability. Longitudinal data on the relation between SLCLA, MSFC, and QoL will be available in the near future.

  7. Evaluation of visual acuity measurements after autorefraction vs manual refraction in eyes with and without diabetic macular edema.

    Science.gov (United States)

    Sun, Jennifer K; Qin, Haijing; Aiello, Lloyd Paul; Melia, Michele; Beck, Roy W; Andreoli, Christopher M; Edwards, Paul A; Glassman, Adam R; Pavlica, Michael R

    2012-04-01

    To compare visual acuity (VA) scores after autorefraction vs manual refraction in eyes of patients with diabetes mellitus and a wide range of VAs. The letter score from the Electronic Visual Acuity (EVA) test from the electronic Early Treatment Diabetic Retinopathy Study was measured after autorefraction (AR-EVA score) and after manual refraction (MR-EVA score), which is the research protocol of the Diabetic Retinopathy Clinical Research Network. Testing order was randomized, study participants and VA examiners were masked to refraction source, and a second EVA test using an identical supplemental manual refraction (MR-EVAsuppl score) was performed to determine test-retest variability. In 878 eyes of 456 study participants, the median MR-EVA score was 74 (Snellen equivalent, approximately 20/32). The spherical equivalent was often similar for manual refraction and autorefraction (median difference, 0.00; 5th-95th percentile range, -1.75 to 1.13 diopters). However, on average, the MR-EVA scores were slightly better than the AR-EVA scores, across the entire VA range. Furthermore, the variability between the AR-EVA scores and the MR-EVA scores was substantially greater than the test-retest variability of the MR-EVA scores (P refraction. Differences between individual autorefractor models were identified. However, even among autorefractor models that compare most favorably with manual refraction, VA variability between autorefraction and manual refraction is higher than the test-retest variability of manual refraction. The results suggest that, with current instruments, autorefraction is not an acceptable substitute for manual refraction for most clinical trials with primary outcomes dependent on best-corrected VA.

  8. Visual Acuity Is Correlated with the Area of the Foveal Avascular Zone in Diabetic Retinopathy and Retinal Vein Occlusion.

    Science.gov (United States)

    Balaratnasingam, Chandrakumar; Inoue, Maiko; Ahn, Seungjun; McCann, Jesse; Dhrami-Gavazi, Elona; Yannuzzi, Lawrence A; Freund, K Bailey

    2016-11-01

    To determine if the area of the foveal avascular zone (FAZ) is correlated with visual acuity (VA) in diabetic retinopathy (DR) and retinal vein occlusion (RVO). Cross-sectional study. Ninety-five eyes of 66 subjects with DR (65 eyes), branch retinal vein occlusion (19 eyes), and central retinal vein occlusion (11 eyes). Structural optical coherence tomography (OCT; Spectralis, Heidelberg Engineering) and OCT angiography (OCTA; Avanti, Optovue RTVue XR) data from a single visit were analyzed. FAZ area, point thickness of central fovea, central 1-mm subfield thickness, the occurrence of intraretinal cysts, ellipsoid zone disruption, and disorganization of retinal inner layers (DRIL) length were measured. VA was also recorded. Correlations between FAZ area and VA were explored using regression models. Main outcome measure was VA. Mean age was 62.9±13.2 years. There was no difference in demographic and OCT-derived anatomic measurements between branch retinal vein occlusion and central retinal vein occlusion groups (all P ≥ 0.058); therefore, data from the 2 groups were pooled together to a single RVO group for further statistical comparisons. Univariate and multiple regression analysis showed that the area of the FAZ was significantly correlated with VA in DR and RVO (all P ≤ 0.003). The relationship between FAZ area and VA varied with age (P = 0.026) such that for a constant FAZ area, an increase in patient age was associated with poorer vision (rise in logarithm of the minimum angle of resolution visual acuity). Disruption of the ellipsoid zone was significantly correlated with VA in univariate and multiple regression analysis (both P retinal vascular diseases and following treatment is warranted. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  9. VEP-based acuity assessment in low vision.

    Science.gov (United States)

    Hoffmann, Michael B; Brands, Jan; Behrens-Baumann, Wolfgang; Bach, Michael

    2017-10-04

    Objective assessment of visual acuity (VA) is possible with VEP methodology, but established with sufficient precision only for vision better than about 1.0 logMAR. We here explore whether this can be extended down to 2.0 logMAR, highly desirable for low-vision evaluations. Based on the stepwise sweep algorithm (Bach et al. in Br J Ophthalmol 92:396-403, 2008) VEPs to monocular steady-state brief onset pattern stimulation (7.5-Hz checkerboards, 40% contrast, 40 ms on, 93 ms off) were recorded for eight different check sizes, from 0.5° to 9.0°, for two runs with three occipital electrodes in a Laplace-approximating montage. We examined 22 visually normal participants where acuity was reduced to ≈ 2.0 logMAR with frosted transparencies. With the established heuristic algorithm the "VEP acuity" was extracted and compared to psychophysical VA, both obtained at 57 cm distance. In 20 of the 22 participants with artificially reduced acuity the automatic analysis indicated a valid result (1.80 logMAR on average) in at least one of the two runs. 95% test-retest limits of agreement on average were ± 0.09 logMAR for psychophysical, and ± 0.21 logMAR for VEP-derived acuity. For 15 participants we obtained results in both runs and averaged them. In 12 of these 15 the low-acuity results stayed within the 95% confidence interval (± 0.3 logMAR) as established by Bach et al. (2008). The fully automated analysis yielded good agreement of psychophysical and electrophysiological VAs in 12 of 15 cases (80%) in the low-vision range down to 2.0 logMAR. This encourages us to further pursue this methodology and assess its value in patients.

  10. Impact of surgery on visual acuity and life quality of senile patients

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    Mariela Julia Curbelo Gómez

    2009-09-01

    Full Text Available Background: Cataract surgery is widely accepted nowadays since it helps improving vision and life quality. Objective: To assess the visual outcome, life quality and advantages of microsurgery in one of the most common visual diseases. Methods: A prospective, descriptive, study including variables as age, gender, general and visual personal pathological history of all the patients who attended to the provisional consultation of the General Hospital “Dr. Gustavo Aldereguía Lima” in Cienfuegos between January, 1st 2008 and March 31st, 2008. 285 patients of 60 years and more were studied using questionnaires and a complete ophthalmological study. Results: Two months after the surgery it was proved that visual sharpness improved significantly reaching 0,5 and more in almost all the patients (97,2 %; 96,8% changes their life quality after the surgery. Satisfaction degree was 96.9 % and 96.8 %. Conclusions: We recommend this surgery since the operated patients present evidences of improvement in visual functioning and sharpness and life quality compared with their conditions before the surgery.

  11. Long-term preservation of cone photoreceptors and visual acuity in rd10 mutant mice exposed to continuous environmental enrichment.

    Science.gov (United States)

    Barone, Ilaria; Novelli, Elena; Strettoi, Enrica

    2014-01-01

    In human patients and animal models of retinitis pigmentosa (RP), a gradual loss of rod photoreceptors and decline in scotopic vision are the primary manifestations of the disease. Secondary death of cones and gradual, regressive remodeling of the inner retina follow and progress at different speeds according to the underlying genetic defect. In any case, the final outcome is near-blindness without a conclusive cure yet. We recently reported that environmental enrichment (EE), an experimental manipulation based on exposure to enhanced motor, sensory, and social stimulation, when started at birth, exerts clear beneficial effects on a mouse model of RP, by slowing vision loss. The purpose of this study was to investigate in the same mouse the long-term effects of chronic exposure to an EE and assess the outcome of this manipulation on cone survival, inner retinal preservation, and visual behavior. Two groups of rd10 mutant mice were maintained in an EE or standard (ST) laboratory conditions up to 1 year of age. Then, retinal preservation was assessed with immunocytochemistry, confocal microscopy examination, cone counts, and electron microscopy of the photoreceptor layer, while visual acuity was tested behaviorally with a Prusky water maze. rd10 mice are a model of autosomal recessive RP with a typical rod-cone, center to the periphery pattern of photoreceptor degeneration. They carry a mutation of the rod-specific phosphodiesterase gene and undergo rod death that peaks at around P24, while cone electroretinogram (ERG) is extinct by P60. We previously showed that early exposure to an EE efficiently delays photoreceptor degeneration in these mutants, extending the time window of cone viability and cone-mediated vision well beyond the phase of maximum rod death. Here we find that a maintained EE can delay the degeneration of cones even in the long term. Confocal and electron microscopy examination of the retinas of the rd10 EE and ST mice at 1 year of age showed major

  12. Near visual acuity in an inner city Hispanic community: understanding the barriers and benefits of correction

    Directory of Open Access Journals (Sweden)

    Thomas Wubben

    2014-07-01

    Full Text Available Presbyopia is age-related loss of accommodation that gradually impairs near vision. Few studies have examined the burden of presbyopia in the United States of America (USA and none have examined it in economically disadvantaged or minority populations, in which there are increased rates of visual impairment and decreased use of eye care services.

  13. Macular morphology and visual acuity after macular hole surgery with or without internal limiting membrane peeling

    DEFF Research Database (Denmark)

    Christensen, U.C.; Kroyer, K.; Sander, B.

    2010-01-01

    Aim: To examine postoperative macular morphology and visual outcome after 12 months in relation to internal limiting membrane (ILM) peeling versus no peeling, indocyanine green (ICG) staining and re-operation in eyes that achieved macular hole closure after surgery. Methods: Seventy-four eyes wit...

  14. Visual acuity and microperimetric mapping of lesion area in eyes with inflammatory cystoid macular oedema

    DEFF Research Database (Denmark)

    Munk, Marion R; Kiss, Christopher G; Huf, Wolfgang

    2014-01-01

    PURPOSE:   To evaluate the effect of fluid accumulation on local visual function in inflammatory cystoid-macular-edema (ICME). METHODS:   This cross-sectional study applied optical-coherence-tomography over a 12×12 fovea-centered field in 50 patients with ICME and mapped the extent of fluid-fille...

  15. Preoperative factors predictive of postoperative decimal visual acuity ≥ 1.0 following surgical treatment for idiopathic epiretinal membrane

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    Hiroshi Kunikata

    2011-02-01

    Full Text Available Hiroshi Kunikata1, Toshiaki Abe2, Jiro Kinukawa1, Kohji Nishida1,31Department of Ophthalmology and Visual Science, Tohoku University Graduate School of Medicine, Sendai, Japan; 2Division of Clinical Cell Therapy, Tohoku University Graduate School of Medicine, Sendai, Japan; 3Department of Ophthalmology, Osaka University Medical School, Suita, JapanPurpose: To report the preoperative best-corrected visual acuity (BCVA and foveal thickness (FT values that lead to a postoperative decimal BCVA of ≥ 1.0 after surgical removal of an idiopathic epiretinal membrane (ERM.Methods: This is a retrospective case series of 73 eyes that underwent surgery for removal of an idiopathic ERM. All eyes had been treated by a single surgeon using a 25-gauge transconjunctival sutureless vitrectomy and indocyanine green-assisted internal limiting membrane peel. The BCVA and FT were measured at baseline and 6 months postoperatively.Results: A postoperative decimal BCVA ≥ 1.0 was obtained in eyes with a preoperative decimal BCVA ≥ 0.3 but not in those with a preoperative decimal BCVA ≤ 0.2. The incidence of obtaining a postoperative decimal BCVA ≥ 1.0 was significantly (P = 0.002 higher in eyes with a preoperative decimal BCVA ≥ 0.5 (50% than in eyes with a preoperative decimal BCVA < 0.5 (11%. Additionally, a postoperative decimal BCVA of ≥ 1.0 was obtained in 51% of the eyes that had a preoperative FT < 400 µm, compared with only 21% of eyes with a preoperative FT ≥ 400 µm (P = 0.01. The incidence of obtaining a postoperative decimal BCVA ≥ 1.0 was significantly higher in eyes with preoperative decimal BCVA ≥ 0.5 and FT < 400 µm (60% than in eyes with preoperative decimal BCVA ≥ 0.5 and FT ≥ 400 µm (20%; P = 0.03 or preoperative BCVA < 0.5 and FT ≥ 400 µm (7%; P < 0.001.Conclusions: These findings indicate that eyes with both preoperative BCVA ≥ 0.5 and FT < 400 µm have a significantly better chance of obtaining a postoperative decimal

  16. Visual Acuity, Retinal Sensitivity, and Macular Thickness Changes in Diabetic Patients without Diabetic Retinopathy after Cataract Surgery

    Science.gov (United States)

    Irman Grčar, Irena; Grčar, Rok; Pfeifer, Vladimir

    2017-01-01

    Aim. Functional and morphological macular study after cataract surgery in a group of diabetics without diabetic retinopathy compared to nondiabetics to evaluate the effect of surgical oxidative stress on diabetic retina. Methods. Prospective, comparative study. Preoperative eye exam, best corrected visual acuity (BCVA) measured by ETDRS letters, and optical coherence tomography (OCT) were followed by standard cataract surgery. The follow-up visits at 1, 3, and 6 months postoperatively included BCVA, OCT, and microperimetry, to analyze changes within and between the groups. Results. The BCVA improved significantly in diabetics and controls: 64.2 to 81.0 and 61.9 to 82.1 ETDRS at 6 months, respectively. The central macula at OCT significantly thickened in both groups, while the central 5 fields, corresponding to the microperimetry area, subclinically thickened from 284.20 to 291.18 μm at 6 months only in diabetics (p = 0.026). A matching slight decrease in the microperimetry sensitivity from 1 to 6 months was found also only in diabetics, with mean average difference −0.75 dB (p = 0.04). Conclusion. Underlying diabetes does not influence the surgical outcome in diabetics without diabetic retinopathy. However, slight thickening of wider macula and corresponding decrease in retinal sensitivity observed in diabetics 6 months postoperatively might influence visual function on long term. PMID:28243608

  17. The Potential Importance of Detection of Neovascular Age-Related Macular Degeneration When Visual Acuity Is Relatively Good.

    Science.gov (United States)

    Ho, Allen C; Albini, Thomas A; Brown, David M; Boyer, David S; Regillo, Carl D; Heier, Jeffrey S

    2017-03-01

    The advent of anti-vascular endothelial growth factor treatment has changed the prognosis for patients with neovascular age-related macular degeneration (nvAMD). The ability to stabilize or improve vision with these treatments is a major step in enabling patients to continue to function at the highest possible level. Many studies have demonstrated that the better the visual acuity (VA) is at the time of treatment initiation, the higher the likelihood that VA will be better during at least the following 2 years; as such, detection of nvAMD when VA is relatively good is important. Data on the VA of patients with intermediate AMD and VA at the time of nvAMD diagnosis suggest that patients are typically losing an average of 3 to 5 lines of vision and possibly more between the time that intermediate AMD progresses to nvAMD and the diagnosis of nvAMD is made. The average patient may have nvAMD for 6 to 12 months before diagnosis and treatment initiation. Current efforts in management of nvAMD are primarily aimed at optimizing anti-vascular endothelial growth factor treatments that have the potential to improve VA outcomes by a magnitude of letters. Additional tools or other efforts to identify patients with nvAMD before substantial vision loss has occurred may reduce the amount of visual loss sustained with anti-vascular endothelial growth factor therapy, and have the potential to improve VA outcomes substantially.

  18. Effect of letter separation on computerised visual acuity measurements: comparison with the gold standard Early Treatment Diabetic Retinopathy Study (ETDRS) chart.

    Science.gov (United States)

    Shah, Nilpa; Laidlaw, D Alistair H; Brown, Graham; Robson, Chloe

    2010-03-01

    Contour interaction plays an important role in letter recognition and has long been known to influence clinical visual acuity measurements. LogMAR charts originally employed between-letter and line spacing of one letter width/height; however, in more recent designs, half letter width spacing has become accepted without validation. COMPlog is a computerised visual acuity measurement device being developed and validated for routine and research clinical use and is available commercially. This study was performed to investigate the effect of letter separation on computerised visual acuity measurements. An iterative series of experiments was performed in which test and retest fully interpolated five letters-per-line logMAR visual acuity measurements were taken in three groups of a total 100 adult subjects. Each group had visual acuity measured using ETDRS charts 1 and 2 and on COMPlog using various combinations of letter and line spacing. The first group consisted of 31 subjects tested using 3.75 and 2.50 stroke width spacing, the second 45 subjects using 2.50 and 1.25 stroke width spacing and the last group, 24 subjects tested using 1.90 stroke width spacing. The methods of Bland and Altman were used to analyse the data. No significant bias was noted between the gold standard ETDRS measurements and those taken using COMPlog with 3.75 stroke width spacing. Significant bias of half a logMAR line was found with crowding of 1.90 and 1.25 stroke widths. A small systematic bias with a reduction of 1 ETDRS letter was found with spacing of 2.50 stroke widths which has not been demonstrated in previous validation studies. Crowding of 2.50 stroke widths is the smallest spacing which can be used in the design of COMPlog.

  19. Macular edema in Asian Indian premature infants with retinopathy of prematurity: Impact on visual acuity and refractive status after 1-year

    Directory of Open Access Journals (Sweden)

    Anand Vinekar

    2015-01-01

    Full Text Available Purpose: To report the impact of transient, self-resolving, untreated "macular edema" detected on spectral domain optical coherence tomography in Asian Indian premature infants with retinopathy of prematurity (ROP on visual acuity (VA and refraction at 1-year of corrected age. Materials and Methods: Visual acuity and refraction of 11 infants with bilateral macular edema (Group A was compared with gestational age-matched 16 infants with ROP without edema (Group B and 17 preterms infants without ROP and without edema (Group C at 3, 6, 9 and 12 months of corrected age using Teller Acuity Cards and cycloplegic retinoscopy. Sub-group analysis of the previously described pattern A and B macular edema was performed. Results: Visual acuity was lower in infants with macular edema compared with the other two control groups throughout the study period, but statistically significant only at 3 months. Visual improvement in these infants was highest between the 3 rd and 6 th month and plateaued by the end of the 1 st year with acuity comparable to the other two groups. The edema cohort was more hyperopic compared to the other two groups between 3 and 12 months of age. Pattern A edema had worse VA compared to pattern B, although not statistically significant. Conclusion: Macular edema, although transient, caused reduced VA as early as 3 months of corrected age in Asian Indian premature infants weighing <2000 g at birth. The higher hyperopia in these infants is possibly due to visual disturbances caused at a critical time of fovealization. We hypothesize a recovery and feedback mechanism based on the principles of active emmetropization to explain our findings.

  20. Determinants of visual acuity outcomes in eyes with neovascular AMD treated with anti-VEGF agents: an instrumental variable analysis of the AURA study.

    Science.gov (United States)

    Holz, F G; Tadayoni, R; Beatty, S; Berger, A R; Cereda, M G; Hykin, P; Staurenghi, G; Wittrup-Jensen, K; Nilsson, J; Kim, K; Sivaprasad, S

    2016-08-01

    PurposeTo identify the strongest variable(s) linked with the number of ranibizumab injections and outcomes in AURA, and to identify ways to improve outcomes using this association.MethodsAURA was a large observational study that monitored visual acuity over a 2-year period in patients with neovascular age-related macular degeneration (AMD) who received ranibizumab injections. Baseline characteristics, resource use, and outcomes were analyzed using an instrumental variable approach and regression analysis.ResultsData were analyzed from 2227 patients enrolled in AURA. Optical coherence tomography (OCT) and ophthalmoscopy were the most common diagnostic tests used, and this combination was the strongest instrumental variable. Use of OCT and ophthalmoscopy affected the number of injections given and resulted in an increase in visual acuity gains from baseline of 17.6 letters in year 1 and 2.5 letters in year 2. Regression models using the instrumental variable (OCT and ophthalmoscopy combined) showed that ≥5.1 (95% CI: 3.3-11.4) ranibizumab injections were needed to maintain visual acuity from baseline to year 1 and ≥8.3 (95% CI: 5.3-18.8) injections were needed to maintain visual acuity from year 1 to year 2. To gain ≥15 letters, ≥7.9 (95% CI: 5.1-17.5) ranibizumab injections would be needed in year 1 and ≥16.1 (95% CI: 10.3-36.4) injections would be needed over 2 years.ConclusionsThese findings highlight the role that regular monitoring plays in guiding neovascular AMD therapy and they showed that the number of ranibizumab injections needed to maintain visual acuity is higher than that administered in AURA.

  1. Visual acuity testing using autorefraction or pinhole occluder compared with a manual protocol refraction in individuals with diabetes.

    Science.gov (United States)

    Sun, Jennifer K; Aiello, Lloyd Paul; Cavallerano, Jerry D; Stockman, Margaret; Miller, Kellee M; Qin, Haijing; Beck, Roy W; Glassman, Adam R

    2011-03-01

    To compare visual acuity (VA) scores obtained after autorefraction or using a pinhole occluder to scores obtained after refraction according to a standard clinical research protocol. Prospective, comparative case series. One hundred ten study participants (209 eyes) with diabetes mellitus and a broad range of diabetic retinopathy severity and VA. We measured VA after autorefraction by a Topcon KR-8000 autorefractor as well as after a Diabetic Retinopathy Clinical Research Network (DRCR.net) protocol manual refraction. The order of testing was randomized and examiners were masked to the source of each refraction. A second VA measurement, utilizing an identical DRCR.net manual refraction, was made in a subset of eyes (n = 144; 69%) to establish test-retest variability for comparison purposes. All eyes underwent VA testing using a pinhole occluder. Best corrected VA as measured by the Electronic Early Treatment Diabetic Retinopathy Study Visual Acuity Test (E-ETDRS). In all eyes, the median E-ETDRS VA letter score (EVA) obtained after manual refraction (MR-EVA) was 69 (Snellen equivalent 20/40), ranging from 4 to 93 (20/800 to 20/16). The median MR-EVA was slightly better than the median EVA obtained after autorefraction (AR-EVA), with a median difference (AR-EVA - MR-EVA) of -1 letter (25th, 75th percentiles, -4, 2 letters). The absolute difference between AR-EVA and MR-EVA was similar to the test-retest variability of MR-EVA alone. In contrast, MR-EVA was better than EVA obtained using a pinhole occluder (PH-EVA; median PH-EVA - MR-EVA, -4 letters [-9, 0]), and had significantly less test-retest variability (Prefraction (median difference, +0.25 diopters [0, +0.63]). Given the substantial time and effort required for training and certification of study protocol refractionists, and the similarity between AR-EVA and MR-EVA, further evaluation of autorefraction, but not pinhole occluder testing, as an alternative to the current clinical research gold standard of ETDRS

  2. The effects of ranibizumab injections on fluorescein angiographic findings and visual acuity recovery in age-related macular degeneration

    Directory of Open Access Journals (Sweden)

    Gungel H

    2014-05-01

    Full Text Available Hulya Gungel,1 Ozen Ayranci Osmanbasoglu,1 Cigdem Altan,2 Deniz Oygar Baylancicek,3 Isil Basgil Pasaoglu2 1Istanbul Education and Research Hospital, Eye Clinic, 2Beyoglu Eye Education and Research Hospital, 3Kudret Eye Hospital, Istanbul, Turkey Aim: The objective of the study reported here was to evaluate the effect of ranibizumab on retinal circulation times and vessel caliber and to analyze the correlation of these factors with visual acuity (VA prognosis in patients with age-related macular degeneration (AMD.Subjects and methods: This prospective cohort study included 52 eyes of 46 patients (mean age 73.5 years [standard deviation 7.7]; 28 males, 18 females. The study parameters were best-corrected visual acuity (BCVA, central macular thickness (CMT (pre- and posttreatment: for 3 months after the last injection, retinal circulation times, diameter of retinal arteriole (DRA, and diameter of retinal vein (DRV (pre- and posttreatment: after a loading dose of three consecutive injections of ranibizumab with a 4-week interval in the initial phase. The pretreatment, posttreatment measurements, and their differences were recorded for analyses. The injections were repeated when needed. Eyes were grouped into one of two groups according to VA recovery: Group 1, cases showing significant recovery of VA (n=21, 37%, and Group 2, cases showing preservation of VA (n=22, 42% and deterioration of VA (n=11, 21%. Differences were compared statistically in and between groups. Logistic regression analysis was undertaken to determine the correlation of these parameters with VA recovery.Results: There was a significant reduction in DRA (P=0.007 and CMT levels (P=0.001 in both study groups after treatment. When the two groups were compared, the differences in pretreatment values of DRA (P=0.001, DRV (P=0.017, CMT (P=0.039, and mean BCVA (P=0.00 were found to be statistically significant. Posttreatment changes in DRA (P=0.013 and mean CMT (P=0

  3. Long-term outcomes of penetrating keratoplasty in keratoconus:analysis of the factors associated with final visual acuities

    Directory of Open Access Journals (Sweden)

    Jin A Choi

    2014-06-01

    Full Text Available AIM: To investigate the long-term results of penetrating keratoplasty (PK in patients with keratoconus (KC and to evaluate factors that might influence the final visual outcome.METHODS:We retrospectively reviewed the data of all patients with clinical KC who had undergone PK by a single corneal surgeon in a single center from May 1980 to December 2005. The age of the patients, preoperative best-corrected visual acuity (BCVA, corneal thickness, death to preservation time, and preservation to transplantation time were recorded. Additionally, postoperative complications such as graft rejection, development of glaucoma and specular microscopy were checked during the follow-up.RESULTS:Sixty-nine eyes from 69 patients were finally included. The follow-up period was 8.64±6.13y. Graft rejection occurred in 4 eyes of 69 cases (5.8%, and the time to graft rejection was 2.1±1.3y. A Kaplan–Meier survival analysis showed that the estimated cumulative probability of graft rejection at 6, 13, and 17y after PK were 95.6%, 90.0%, and 78.8%, respectively. When we evaluated factors that might influence final BCVA in eyes, no disparity donor-host trephine size (same graft size as well as higher spherical equivalent, and average K-value were associated with higher final BCVA. (P=0.006, 0.051, 0.092, and 0.021 in eyes with follow-up <8y; P=0.068, 0.065, and 0.030 in eyes with follow-up ≥8y, respectively.CONCLUSION: The long-term results of PK in patients with KC were favorable with a high percentage of good BCVA. Less myopic change and low average K-reading, as well as a surgical technique using the same size donor-recipient button may provide better visual outcomes particularly in patients with KC.

  4. Complex for monitoring visual acuity and its application for evaluation of human psycho-physiological state

    Science.gov (United States)

    Sorokoumov, P. S.; Khabibullin, T. R.; Tolstaya, A. M.

    2017-01-01

    The existing psychological theories associate the movement of a human eye with its reactions to external change: what we see, hear and feel. By analyzing the glance, we can compare the external human response (which shows the behavior of a person), and the natural reaction (that they actually feels). This article describes the complex for detection of visual activity and its application for evaluation of the psycho-physiological state of a person. The glasses with a camera capture all the movements of the human eye in real time. The data recorded by the camera are transmitted to the computer for processing implemented with the help of the software developed by the authors. The result is given in an informative and an understandable report, which can be used for further analysis. The complex shows a high efficiency and stable operation and can be used both, for the pedagogic personnel recruitment and for testing students during the educational process.

  5. Change in visual acuity is well correlated with change in image-quality metrics for both normal and keratoconic wavefront errors.

    Science.gov (United States)

    Ravikumar, Ayeswarya; Marsack, Jason D; Bedell, Harold E; Shi, Yue; Applegate, Raymond A

    2013-11-26

    We determined the degree to which change in visual acuity (VA) correlates with change in optical quality using image-quality (IQ) metrics for both normal and keratoconic wavefront errors (WFEs). VA was recorded for five normal subjects reading simulated, logMAR acuity charts generated from the scaled WFEs of 15 normal and seven keratoconic eyes. We examined the correlations over a large range of acuity loss (up to 11 lines) and a smaller, more clinically relevant range (up to four lines). Nine IQ metrics were well correlated for both ranges. Over the smaller range of primary interest, eight were also accurate and precise in estimating the variations in logMAR acuity in both normal and keratoconic WFEs. The accuracy for these eight best metrics in estimating the mean change in logMAR acuity ranged between ±0.0065 to ±0.017 logMAR (all less than one letter), and the precision ranged between ±0.10 to ±0.14 logMAR (all less than seven letters).

  6. Are blind people more likely to accept free cataract surgery? A study of vision-related quality of life and visual acuity in Kenya.

    Science.gov (United States)

    Briesen, Sebastian; Roberts, Helen; Ilako, Dunera; Karimurio, Jefitha; Courtright, Paul

    2010-01-01

    To determine possible differences in visual acuity, socio-demographic factors and vision-related Quality of Life (QoL) between people accepting and people refusing sponsored cataract surgery. Three hundred and fifty seven local residents with visually impairing cataract, presenting at screening sites in Kwale District, Kenya were clinically assessed and interviewed. The World Health Organization (WHO) QoL-questionnaire WHO/Prevention of Blindness and Deafness Visual Functioning Questionnaire 20 (PBD-VFQ20) was used to determine the vision-related QoL. A standardized questionnaire asked for socio-demographic data and prior cataract surgery in one eye. After interview, patients were offered free surgery. Primary outcome was the mean QoL-score between acceptors and non-acceptors. Secondary outcomes were visual acuity and socio-demographic factors and their contribution to QoL-scores and the decision on acceptance or refusal. Fifty nine people (16.5%) refused and 298 accepted cataract surgery. Vision-related QoL was poorer in people accepting than in those refusing (mean score 51.54 and 43.12 respectively). People with poor visual acuity were only slightly more likely to accept surgery than people with better vision; the strongest predictors of acceptance were the QoL-score and gender. Men were twice as likely to accept compared to women. Of people who accepted surgery, 73.8% had best eye vision of 20/200 or better. In this population, visual acuity was of limited use to predict a person's decision to accept or refuse cataract surgery. QoL-scores provide further insight into which individuals will agree to surgery and it might be useful to adapt the QoL-questions for field use. Gender inequities remain a matter of concern with men being more likely to get sight-restoring surgery.

  7. Sports can protect dynamic visual acuity from aging: A study with young and older judo and karate martial arts athletes.

    Science.gov (United States)

    Muiños, Mónica; Ballesteros, Soledad

    2015-08-01

    A major topic of current research in aging has been to investigate ways to promote healthy aging and neuroplasticity in order to counteract perceptual and cognitive declines. The aim of the present study was to investigate the benefits of intensive, sustained judo and karate martial arts training in young and older athletes and nonathletes of the same age for attenuating age-related dynamic visual acuity (DVA) decline. As a target, we used a moving stimulus similar to a Landolt ring that moved horizontally, vertically, or obliquely across the screen at three possible contrasts and three different speeds. The results indicated that (1) athletes had better DVA than nonathletes; (2) the older adult groups showed a larger oblique effect than the younger groups, regardless of whether or not they practiced a martial art; and (3) age modulated the results of sport under the high-speed condition: The DVA of young karate athletes was superior to that of nonathletes, while both judo and karate older athletes showed better DVA than did sedentary older adults. These findings suggest that in older adults, the practice of a martial art in general, rather than the practice of a particular type of martial art, is the crucial thing. We concluded that the sustained practice of a martial art such as judo or karate attenuates the decline of DVA, suggesting neuroplasticity in the aging human brain.

  8. Zagreb Amblyopia Preschool Screening Study: near and distance visual acuity testing increase the diagnostic accuracy of screening for amblyopia.

    Science.gov (United States)

    Bušić, Mladen; Bjeloš, Mirjana; Petrovečki, Mladen; Kuzmanović Elabjer, Biljana; Bosnar, Damir; Ramić, Senad; Miletić, Daliborka; Andrijašević, Lidija; Kondža Krstonijević, Edita; Jakovljević, Vid; Bišćan Tvrdi, Ana; Predović, Jurica; Kokot, Antonio; Bišćan, Filip; Kovačević Ljubić, Mirna; Motušić Aras, Ranka

    2016-02-01

    To present and evaluate a new screening protocol for amblyopia in preschool children. Zagreb Amblyopia Preschool Screening (ZAPS) study protocol performed screening for amblyopia by near and distance visual acuity (VA) testing of 15 648 children aged 48-54 months attending kindergartens in the City of Zagreb County between September 2011 and June 2014 using Lea Symbols in lines test. If VA in either eye was >0.1 logMAR, the child was re-tested, if failed at re-test, the child was referred to comprehensive eye examination at the Eye Clinic. 78.04% of children passed the screening test. Estimated prevalence of amblyopia was 8.08%. Testability, sensitivity, and specificity of the ZAPS study protocol were 99.19%, 100.00%, and 96.68% respectively. The ZAPS study used the most discriminative VA test with optotypes in line as they do not underestimate amblyopia. The estimated prevalence of amblyopia was considerably higher than reported elsewhere. To the best of our knowledge, the ZAPS study protocol reached the highest sensitivity and specificity when evaluating diagnostic accuracy of VA tests for screening. The pass level defined at ≤0.1 logMAR for 4-year-old children, using Lea Symbols in lines missed no amblyopia cases, advocating that both near and distance VA testing should be performed when screening for amblyopia.

  9. RELATIONSHIP BETWEEN RETINAL THICKNESS AND VISUAL ACUITY IN EYES WITH RETINAL VEIN OCCLUSION TREATED WITH DEXAMETHASONE IMPLANT.

    Science.gov (United States)

    Danis, Ronald P; Sadda, Srinivas; Jiao, Jenny; Li, Xiao-Yan; Whitcup, Scott M

    2016-06-01

    To evaluate the relationship between changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) in eyes from two clinical trials of dexamethasone intravitreal implant 0.7 mg for macular edema after branch or central retinal vein occlusion. Patients with vision loss as a result of macular edema (≥6-week duration) after branch retinal vein occlusion or central retinal vein occlusion were treated with a single dexamethasone intravitreal implant or sham. Prospectively defined outcomes included BCVA and CRT (as assessed by optical coherence tomography). There was a modest but statistically significant negative linear correlation between changes in CRT and changes in BCVA in both treatment groups at Days 90 and 180 (correlation coefficient: -0.23 to -0.34; P < 0.001). Improvements in BCVA at Day 180 were significantly greater (P < 0.001) in eyes that achieved and maintained CRT ≤250 μm from Day 90 to 180 (mean BCVA improvement: 14 letters; 49% of eyes with ≥15-letter gain) than in eyes that never achieved CRT ≤250 μm (mean BCVA improvement: 2 letters; 13% of eyes with ≥15-letter gain). The greatest improvements in BCVA were seen in eyes that achieved and maintained the greatest improvements in CRT.

  10. Monocular denervation of visual nuclei modulates APP processing and sAPPα production: A possible role on neural plasticity.

    Science.gov (United States)

    Vasques, Juliana Ferreira; Heringer, Pedro Vinícius Bastos; Gonçalves, Renata Guedes de Jesus; Campello-Costa, Paula; Serfaty, Claudio Alberto; Faria-Melibeu, Adriana da Cunha

    2017-08-01

    Amyloid precursor protein (APP) is essential to physiological processes such as synapse formation and neural plasticity. Sequential proteolysis of APP by beta- and gamma-secretases generates amyloid-beta peptide (Aβ), the main component of senile plaques in Alzheimer Disease. Alternative APP cleavage by alpha-secretase occurs within Aβ domain, releasing soluble α-APP (sAPPα), a neurotrophic fragment. Among other functions, sAPPα is important to synaptogenesis, neural survival and axonal growth. APP and sAPPα levels are increased in models of neuroplasticity, which suggests an important role for APP and its metabolites, especially sAPPα, in the rearranging brain. In this work we analyzed the effects of monocular enucleation (ME), a classical model of lesion-induced plasticity, upon APP content, processing and also in secretases levels. Besides, we addressed whether α-secretase activity is crucial for retinotectal remodeling after ME. Our results showed that ME induced a transient reduction in total APP content. We also detected an increase in α-secretase expression and in sAPP production concomitant with a reduction in Aβ and β-secretase contents. These data suggest that ME facilitates APP processing by the non-amyloidogenic pathway, increasing sAPPα levels. Indeed, the pharmacological inhibition of α-secretase activity reduced the axonal sprouting of ipsilateral retinocollicular projections from the intact eye after ME, suggesting that sAPPα is necessary for synaptic structural rearrangement. Understanding how APP processing is regulated under lesion conditions may provide new insights into APP physiological role on neural plasticity. Copyright © 2017 ISDN. Published by Elsevier Ltd. All rights reserved.

  11. A Research on Monocular Visual SLAM Based on SURF Feature%基于SURF特征的单目视觉SLAM方法研究∗

    Institute of Scientific and Technical Information of China (English)

    胡衡; 梁岚珍

    2015-01-01

    Because the visual information is easily affected by external environment factors, therefore the selected feature points of mobile robot based on visual simultaneous localization and map building requires high stability and good robustness. For the problem of monocular visual mobile robot SLAM(Simultaneous Localization and Mapping),a kind of mono-SLAM algorithm based on Extended kalman filter is proposed by using SURF(Speed Up Robust Features) feature points and the inverse depth method. The process of SLAM is completed by fusing the information of SURF features and robot information with EKF. The result of simulation experiment indicates that the proposed algorithm is feasible, and with high localization precision in indoor structured environment.%由于视觉信息很容易受到外界环境因素的影响,因此基于视觉的移动机器人同步定位与地图构建问题所选取的特征点要求具有较高的精确度和良好的鲁棒性。针对单目SLAM问题,提出一种基于扩展卡尔曼滤波器的单目视觉SLAM算法。该算法采用SURF特征点,结合反向深度估计法,应用扩展卡尔曼滤波器融合SURF特征信息与机器人位姿信息完成SLAM过程。仿真实验结果表明,在未知室内结构化环境下,该算法运行可靠,定位精度高。

  12. A switch from inter-ocular to inter-hemispheric suppression following monocular deprivation in the rat visual cortex

    NARCIS (Netherlands)

    Pietrasanta, M.; Restani, L.; Cerri, C.; Olcese, U.; Medini, P.; Caleo, M.

    2014-01-01

    Binocularity is a key property of primary visual cortex (V1) neurons that is widely used to study synaptic integration in the brain and plastic mechanisms following an altered visual experience. However, it is not clear how the inputs from the two eyes converge onto binocular neurons, and how their

  13. RETINAL MICROVASCULATURE AND VISUAL ACUITY AFTER INTRAVITREAL AFLIBERCEPT IN EYES WITH CENTRAL RETINAL VEIN OCCLUSION: An Optical Coherence Tomography Angiography Study.

    Science.gov (United States)

    Winegarner, Andrew; Wakabayashi, Taku; Hara-Ueno, Chikako; Sato, Tatsuhiko; Busch, Caleb; Fukushima, Yoko; Sayanagi, Kaori; Nishida, Kentaro; Sakaguchi, Hirokazu; Nishida, Kohji

    2017-09-07

    To investigate vascular perfusion and foveal avascular zone area in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) after intravitreal aflibercept therapy in central retinal vein occlusion eyes and their association with best-corrected visual acuity. Thirty-five subjects with central retinal vein occlusion and macular edema were evaluated. After macular edema resolution following intravitreal aflibercept, subjects underwent optical coherence tomography angiography to measure SCP and DCP perfusion and the foveal avascular zone within a 3 × 3-mm area. Correlations between best-corrected visual acuity and optical coherence tomography angiography measurements were examined. After intravitreal aflibercept therapy, mean retinal vascular area was 3.41 ± 0.74 mm in the SCP and 3.25 ± 0.91 mm in the DCP. Foveal avascular zone area was 1.03 ± 1.04 mm in the SCP and 1.78 ± 1.73 mm in the DCP. Improved best-corrected visual acuity was significantly associated with better SCP and DCP perfusion (both P retinal perfusion and less retinal ischemia are associated with better visual outcomes after aflibercept in eyes with central retinal vein occlusion.

  14. Monocular blur alters the tuning characteristics of stereopsis for spatial frequency and size.

    Science.gov (United States)

    Li, Roger W; So, Kayee; Wu, Thomas H; Craven, Ashley P; Tran, Truyet T; Gustafson, Kevin M; Levi, Dennis M

    2016-09-01

    Our sense of depth perception is mediated by spatial filters at different scales in the visual brain; low spatial frequency channels provide the basis for coarse stereopsis, whereas high spatial frequency channels provide for fine stereopsis. It is well established that monocular blurring of vision results in decreased stereoacuity. However, previous studies have used tests that are broadband in their spatial frequency content. It is not yet entirely clear how the processing of stereopsis in different spatial frequency channels is altered in response to binocular input imbalance. Here, we applied a new stereoacuity test based on narrow-band Gabor stimuli. By manipulating the carrier spatial frequency, we were able to reveal the spatial frequency tuning of stereopsis, spanning from coarse to fine, under blurred conditions. Our findings show that increasing monocular blur elevates stereoacuity thresholds 'selectively' at high spatial frequencies, gradually shifting the optimum frequency to lower spatial frequencies. Surprisingly, stereopsis for low frequency targets was only mildly affected even with an acuity difference of eight lines on a standard letter chart. Furthermore, we examined the effect of monocular blur on the size tuning function of stereopsis. The clinical implications of these findings are discussed.

  15. Hierarchical linear modeling of visual acuity change over time: rate of functional recovery after macular hole surgery.

    Science.gov (United States)

    Wittich, Walter; Overbury, Olga; Kapusta, Michael A; Watanabe, Donald H

    2007-09-01

    To examine acuity recovery rate after Macular Hole (MH) surgery, using Hierarchical Linear Modeling (HLM) with linear and curvilinear regression analysis. Preoperative MH diameter (OCT) and acuity (ETDRS) were recorded in 20 eyes. Acuities were tested during follow-up (6 to 23 months), with three to eight measurements per eye. The resulting 95 acuities were analyzed using HLM. Variability at the level of the person was explained by change over time, using a natural logarithm conversion. Across patients, MH diameter was used to predict slopes and intercepts at the level of the individual. MH diameter was able to account for significant amounts of variability in preoperative acuity (intercept) and significantly influenced rate of functional recovery (slope). A nonlinear approach to the data accounted for the largest amount of variance. Participants with larger MHs recovered relatively more acuity sooner while eyes with smaller MHs had better absolute acuity outcome. HLM provides important insight into the recovery process after MH surgery and is more flexible with follow-up data. In the context of MH treatment, most recuperation occurred during the initial 6 months.

  16. Improvement of visual acuity based on optical coherence tomography patterns following intravitreal bevacizumab treatment in patients with diabetic macular edema

    Directory of Open Access Journals (Sweden)

    Haider R. Cheema

    2014-04-01

    Full Text Available AIM:To report the visual outcome based on various patterns of optical coherence tomography (OCT morphology in diabetic macular edema (DME, following treatment with anti-VEGF intravitreal bevacizumab (IVB injection.METHODS:Sixty-seven consecutive subjects with centre involving DME underwent intravitreal injection of Bevacizumab (1.25 mg/0.05 mL in this retrospective, comparative, non randomized study. The DME was classified into one of four categories:focal, diffuse, focal cystoid and neurosensory detachment based on OCT. Best corrected visual acuity (BCVA, macular appearance, and OCT findings were used to decide whether the subject should have a repeat injection of intravitreal bevacizumab. Outcome measures were a change in mean BCVA (Snellen converted to logMAR and central macular thickness (CMT in each group during the six month follow-up period.RESULTS:The mean BCVA improved to logMAR 0.23 at final follow-up from a baseline of 0.32 logMAR (P=0.040 in the focal group, logMAR 0.80 at final follow-up from a baseline of 0.82 logMAR (P=0.838 in the diffuse group, worsened to logMAR 0.53 at final follow-up from a baseline of 0.43 logMAR (P=0.276 in the focal cystoid group, and improved to logMAR 0.79 at final follow-up from a baseline of 0.93 logMAR (P=0.490 in the neurosensory detachment group. The mean CMT before treatment were 298.8±25.03 μm in the focal group, 310.8±40.6 μm in the diffuse group, 397.15±31.05 μm in the focal cystoid group and 401.03±75.1 μm in the neurosensory detachment group. A mean of 2.05 (range:1-5 injections in the focal group, 1.32 (range:1-2 in the diffuse group, 2.6 (range:1-6 in the focal cystoid group and 2.6 (range:1-6 in the neurosensory detachment group were performed during the six month follow-up period. Following intravitreal bevacizumab treatment, vision improved, remained unchanged or worsened in 11, 7 and 2 subjects in focal group; 11, 9 and 8 in diffuse group; 0, 2 and 4 in focal cystoid group and 5

  17. Intravitreal ranibizumab therapy versus photodynamic therapy for idiopathic choroidal neovascularization: a comparative study on visual acuity, retinal and choroidal thickness

    Institute of Scientific and Technical Information of China (English)

    Shi Xuehui; Wei Wenbin; Zhang Cong

    2014-01-01

    Background Photodynamic therapy (PDT) has been recommended as a main treatment for idiopathic choroidal neovascularization (I-CNV).But the visual results of PDT were inconsistent and variable,and PDT may bring severe damage to the retinal pigment epithelium and choriocapillaries.In recent years,intravitreal ranibizumab therapy,showing favorable visual outcomes,has developed as an advanced treatment for choroidal neovascularization (CNV).Although both methods have been reported to be effective in treating I-CNV,there is no detailed comparative report between the two methods.This study aimed to compare visual outcomes,retinal and choroidal thickness between intravitreal ranibizumab therapy and PDT in the treatment of I-CNV,and investigate the correlation of visual outcomes with retinal and choroidal thickness in each of the two groups.Methods Thirty-seven eyes of 37 patients with I-CNV were involved in this study; 19 eyes were treated with intravitreal ranibizumab therapy and 18 eyes were treated with PDT.The best corrected visual acuity (BCVA) was recorded before and at each follow-up visit after treatments (IogMAR).Enhanced-depth imaging optical coherence tomography (EDI-OCT) was used to evaluate the retinal structural changes,and to measure central retinal thickness (CRT) and central choroidal thickness (CCT).Results Mean BCVA was 0.64±0.27 in PDT group and 0.69±0.22 in ranibizumab group at baseline (P=0.55).When compared with the baseline,mean BCVA in PDT group was improved significantly at 3-month after PDT (0.41±0.16,P=0.002),then changed little (0.42±0.25 at 12-month,P=0.88).Whereas mean BCVA in Ranibizumab group was improved significantly at each follow-up visit.It improved much more obviously in the first month and then remained stable.The mean BCVA in the ranibizumab group was significantly better at each follow-up visit than that in PDT (P <0.05).When compared with the baseline,mean CRT in PDT group decreased significantly since 3-month visit

  18. Analysis of risk factors for visual acuity and visual field impairments in patients with pituitary adenoma%垂体腺瘤患者视力视野受损的危险因素分析

    Institute of Scientific and Technical Information of China (English)

    周文剑龙; 牛国栋; 管修东; 赵敏; 马顺昌; 刘祥祥; 李德岭; 贾桂军; 贾旺

    2016-01-01

    Objective To investigate the risk factors for visual acuity and visual field impairments,and the effect on their prognoses.Methods The clinical data of 637 patients with pituitary adenoma operated at the Department of Neurosurgery,Beijing Tiantan Hospital,Capital Medical University from January 2008 to December 2013 were analyzed retrospectively.The patients were followed up at 3 years after procedure.Receiver operating characteristic (ROC) curve was used to obtain the optimal critical value of the risk factors for affecting visual acuity and visual field impairments and postoperative recovery.The round numbers were taken to group.Results In 637 patients,436 (68.4%) experienced visual acuity and visual field impairments,414 of them had decreased vision,and 292 had visual field defect.Receiver operating characteristic (ROC) curve showed that (1) the suprasellar extension height of tumors < 12.5 mm tended to cause less visual acuity and visual field impairments in patients.There was significant difference in whether the preoperative visual acuity and visual field were impaired and the degree of visual impairment between the ≤ 10 mm group and the > 10 mm group (all P < 0.01);(2) the suprasellar extension height of the tumors > 18.5 mm,the risk of causing permanent visual acuity and visual field impairments increased.There were significant differences in postoperative visual acuity improvement,visual acuity and visual field impairment score (VIS) grades between the suprasellar extension height of tumors ≤20 mm group and the and > 20 mm group (P < 0.01).There was no significant difference in the improvement of visual field (P > 0.05);(3) the patients with the duration of preoperative visual acuity and visual field impairments >13.5 months,the postoperative visual acuity and visual field impairments were more difficult to improve.There was significant difference between the recovery of visual acuity in patients with the duration of the disease

  19. Impact of visual acuity on developing literacy at age 4–5 years: a cohort-nested cross-sectional study

    OpenAIRE

    Bruce, A.; Fairley, L; Chambers, B; Wright, J.; Sheldon, TA

    2016-01-01

    Objectives: To estimate the prevalence of poor vision in children aged 4-5 years and determine the impact of visual acuity on literacy. Design: Cross-sectional study linking clinical, epidemiological and education data. Setting: Schools located in the city of Bradford, UK. Participants: Prevalence was determined for 11 186 children participating in the Bradford school vision screening programme. Data linkage was undertaken for 5836 Born in Bradford (BiB) birth cohort study children participat...

  20. Collateral vessel presence in branch and central retinal vein occlusions and their impact on visual acuity and anatomical gains: a retrospective analysis.

    Science.gov (United States)

    Singh, Rishi P; Lee, Tamara J; Yau, Linda; Rubio, Roman G

    2014-11-01

    To evaluate the incidence of collateral vessel formation and to determine their impact on best-corrected visual acuity and central foveal thickness in patients with branch or central retinal vein occlusion (BRVO, CRVO) receiving 0.3 mg or 0.5 mg of ranibizumab, or sham. This retrospective analysis was performed in patients with macular edema secondary to retinal vein occlusion who received 6 monthly intravitreal injections of ranibizumab (0.3 mg or 0.5 mg), or sham, followed by 6 months of as-needed treatment. Collateral vessel presence, change from baseline best-corrected visual acuity, and change from baseline central foveal thickness were assessed at baseline and months 3, 6, 9, and 12. At month 12, 19.6% of BRVO patients receiving sham/0.5 mg and 16.7% receiving ranibizumab (0.3 mg and 0.5 mg pooled) manifested collaterals at the disk, whereas 48.2% and 47.2% displayed collaterals within the retina, respectively. In CRVO patients, 57.9% and 59.2% of all groups manifested collaterals on the disk, respectively, whereas 12.1% and 15.1% displayed collaterals within the retina. Mean best-corrected visual acuity gain in ranibizumab-treated BRVO and CRVO patients was similar, irrespective of collaterals within the retina ( P > 0.05; CRVO: P > 0.05). The location of collaterals differed between retinal vein occlusion subtypes and ranibizumab treatment did not affect collateral vessel incidence. The presence of collaterals did not seem to impact best-corrected visual acuity gains at month 12 in both BRVO and CRVO patients receiving ranibizumab, whereas generally greater central foveal thickness reductions were observed with presence of collaterals in BRVO patients.

  1. Evaluation of Visual Acuity Measurements after Autorefraction versus Manual Refraction in Eyes with and without Diabetic Macular Edema

    Science.gov (United States)

    Sun, Jennifer K.; Qin, Haijing; Aiello, Lloyd Paul; Melia, Michele; Beck, Roy W.; Andreoli, Christopher M.; Edwards, Paul A.; Glassman, Adam R.; Pavlica, Michael R.

    2012-01-01

    Objective To compare visual acuity (VA) scores after autorefraction versus research protocol manual refraction in eyes of patients with diabetes and a wide range of VA. Methods Electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) VA Test© letter score (EVA) was measured after autorefraction (AR-EVA) and after Diabetic Retinopathy Clinical Research Network (DRCR.net) protocol manual refraction (MR-EVA). Testing order was randomized, study participants and VA examiners were masked to refraction source, and a second EVA utilizing an identical manual refraction (MR-EVAsupl) was performed to determine test-retest variability. Results In 878 eyes of 456 study participants, median MR-EVA was 74 (Snellen equivalent approximately 20/32). Spherical equivalent was often similar for manual and autorefraction (median difference: 0.00, 5th and 95th percentiles −1.75 to +1.13 Diopters). However, on average, MR-EVA results were slightly better than AR-EVA results across the entire VA range. Furthermore, variability between AR-EVA and MR-EVA was substantially greater than the test-retest variability of MR-EVA (Prefraction. Differences between individual autorefractor models were identified. However, even among autorefractor models comparing most favorably to manual refraction, VA variability between autorefraction and manual refraction is higher than the test-retest variability of manual refraction. The results suggest that with current instruments, autorefraction is not an acceptable substitute for manual refraction for most clinical trials with primary outcomes dependent on best-corrected VA. PMID:22159173

  2. Visual acuity measured with a smartphone app is more accurate than Snellen testing by emergency department providers.

    Science.gov (United States)

    Pathipati, Akhilesh S; Wood, Edward H; Lam, Carson K; Sáles, Christopher S; Moshfeghi, Darius M

    2016-06-01

    To assess the accuracy of best-corrected visual acuity (BCVA) measured by non-ophthalmic emergency department (ED) staff with a standard Snellen chart versus an automated application (app) on a handheld smartphone (Paxos Checkup, San Francisco, CA, USA). The study included 128 subjects who presented to the Stanford Hospital ED for whom the ED requested an ophthalmology consultation. We conducted the study in two phases. During phase 1 of the study, ED staff tested patient BCVA using a standard Snellen test at 20 feet. During phase 2 of the study, ED staff tested patient near BCVA using the app. During both phases, ophthalmologists measured BCVA with a Rosenbaum near chart, which was treated as the gold standard. ED BCVA measurements were benchmarked prospectively against ophthalmologists' measurements and converted to logMAR. ED logMAR BCVA was 0.21 ± 0.35 (approximately 2 Snellen lines difference ± 3 Snellen lines) higher than that of ophthalmologists when ED staff used a Snellen chart (p = .0.00003). ED BCVA was 0.06 ± 0.40 (less than 1 Snellen line ± 4 Snellen lines) higher when ED staff used the app (p = 0.246). Inter-observer difference was therefore smaller by more than 1 line (0.15 logMAR) with the app (p = 0.046). BCVA measured by non-ophthalmic ED staff with an app was more accurate than with a Snellen chart. Automated apps may provide a means to standardize and improve the efficiency of ED ophthalmologic care.

  3. VISUAL ACUITY AND MULTIFOCAL ELECTRORETINOGRAPHIC CHANGES AFTER ARTERIOVENOUS CROSSING SHEATHOTOMY FOR MACULAR EDEMA ASSOCIATED WITH BRANCH RETINAL VEIN OCCLUSION

    Science.gov (United States)

    Chung, Eun Jee; Freeman, William R.; Koh, Hyoung Jun

    2009-01-01

    Purpose To evaluate the influence of arteriovenous (AV) sheathotomy on retinal function with central multifocal electroretinography (mfERG) in eyes with macular edema secondary to branch retinal vein occlusion (BRVO). Methods Fifteen patients (15 eyes) who underwent AV sheathotomy for macular edema secondary to BRVO were included in the study. Best-corrected visual acuity and mfERG responses from the most central seven hexagons were analyzed before and 6 months after the operation. Results The mean preoperative Early Treatment Diabetic Retinopathy Study (ETDRS) score ± SD was 34.1 ± 12.7 letters (Snellen equivalent, 20/50) and significantly improved up to 40.5 ± 10.9 letters (Snellen equivalent, 20/40) at 6 months after AV sheathotomy (P = 0.027, Wilcoxon signed rank test). The mean preoperative P1 amplitude ± SD of the most central 7 hexagons was 39.30 ± 10.86 nV/deg2 for the affected eye versus 47.72 ± 6.67 nV/deg2 for the normal fellow (control) eye (P = 0.013, Mann–Whitney U test) and significantly increased up to 50.71 ± 15.58 nV/deg2 at 6 months after the operation (P = 0.014, Wilcoxon signed rank test). Significant correlations between preoperative and postoperative ETDRS score and preoperative P1 amplitude were present (r = 0.929, P < 0.001; r = 0.768, P = 0.001; respectively [Spearman correlation]). Conclusions AV sheathotomy improved macular function and anatomical outcome as measured by ETDRS score and mfERG responses in patients with macular edema due to BRVO. PMID:18301026

  4. SMARTPHONE-BASED DILATED FUNDUS PHOTOGRAPHY AND NEAR VISUAL ACUITY TESTING AS INEXPENSIVE SCREENING TOOLS TO DETECT REFERRAL WARRANTED DIABETIC EYE DISEASE.

    Science.gov (United States)

    Toy, Brian C; Myung, David J; He, Lingmin; Pan, Carolyn K; Chang, Robert T; Polkinhorne, Alison; Merrell, Douglas; Foster, Doug; Blumenkranz, Mark S

    2016-05-01

    To compare clinical assessment of diabetic eye disease by standard dilated examination with data gathered using a smartphone-based store-and-forward teleophthalmology platform. 100 eyes of 50 adult patients with diabetes from a health care safety-net ophthalmology clinic. All patients underwent comprehensive ophthalmic examination. Concurrently, a smartphone was used to estimate near visual acuity and capture anterior and dilated posterior segment photographs, which underwent masked, standardized review. Quantitative comparison of clinic and smartphone-based data using descriptive, kappa, Bland-Altman, and receiver operating characteristic analyses was performed. Smartphone visual acuity was successfully measured in all eyes. Anterior and posterior segment photography was of sufficient quality to grade in 96 and 98 eyes, respectively. There was good correlation between clinical Snellen and smartphone visual acuity measurements (rho = 0.91). Smartphone-acquired fundus photographs demonstrated 91% sensitivity and 99% specificity to detect moderate nonproliferative and worse diabetic retinopathy, with good agreement between clinic and photograph grades (kappa = 0.91 ± 0.1, P smartphone-based telemedicine system that demonstrated sensitivity and specificity to detect referral-warranted diabetic eye disease as a proof-of-concept. Additional studies are warranted to evaluate this approach to expanding screening for diabetic retinopathy.

  5. [Visual evoked potentials produced by monocular flash stimuli in the cerebral cortex of the rabbit. I. Typography].

    Science.gov (United States)

    Pérez-Cobo, J C; Ruiz-Beramendi, M; Pérez-Arroyo, M

    1990-12-01

    The visually evoked potentials in the hemisphere contralateral to the stimulated eye in rabbit, can be described topographically as follows. While a positive wave (P1) begins forming in the anterior zones and in the V I binocular zone, the N0 wave, at times very large, is produced in a more occipital zone, which corresponds to the visual streak. Immediately afterwards, the positivity, P1, practically invades the whole of the hemisphere. After this, the N1 wave which is produced in the most posterior parts of the V I, begins forming. The whole phenomenon comes to an end when the P2 wave is generated in the most occipital zones.

  6. Monocular Blindness: Is It a Handicap?

    Science.gov (United States)

    Knoth, Sharon

    1995-01-01

    Students with monocular vision may be in need of special assistance and should be evaluated by a multidisciplinary team to determine whether the visual loss is affecting educational performance. This article discusses the student's eligibility for special services, difficulty in performing depth perception tasks, difficulties in specific classroom…

  7. Comparison of visual acuity measurements via three different methods in preschool children: Lea symbols, crowded Lea symbols, Snellen E chart.

    Science.gov (United States)

    Inal, Asli; Ocak, Osman Bulut; Aygit, Ebru Demet; Yilmaz, Ihsan; Inal, Berkay; Taskapili, Muhittin; Gokyigit, Birsen

    2017-06-20

    The aim of this study was to compare three different methods to measure visual acuity (VA) in healthy and amblyopic preschool children: a Snellen E chart (SE), a single Lea symbols (SLS), and a crowded Lea symbols (CLS). Seventy-eight eyes of 54 patients (28 females, 26 males) were included in this cross-sectional, comparative study. The control group consisted of 30 healthy cases, and the amblyopic group consisted of 24 patients with amblyopia. Best-corrected VA (BCVA) measurements with SLS, CLS, and SE were compared in control eyes (CE), amblyopic eyes (AE), and fellow eyes (FE) separately. The mean age of the cohort was 5.7 ± 0.7 years (range 5-7 years). The mean refractive error was +1.02 ± 0.36 D (diopter, spherical equivalent) in CE, +5.59 ± 2.45 D in AE, and +3.96 ± 2.38 D in FE. The median BCVA (logMAR) was (in order of SLS, CLS, and SE) 0.00 [interquartile range (IQR) 0.10], 0.10 (IQR 0.10), 0.00 (IQR 0.10) in CE, 0.25 (IQR 0.33), 0.35 (IQR 0.30), 0.25 (IQR 0.38) in AE, and 0.10 (IQR 0.08), 0.10 (IQR 0.00), 0.10 (IQR 0.10) in FE. There was no statistically significant difference between the three methods in terms of the CE or FE (p > 0.05). In contrast, there was a statistically significant difference in AE (p < 0.05). The mean VA measurement with SLS was higher compared with CLS in AE. A positive and strong correlation between the three charts was found in all of the groups (p < 0.001). We found SLS, CLS, and SE to be consistent: all three methods can be used to obtain measurements of VA in healthy and amblyopic preschool children.

  8. The Best Corrected Presenting Distance Visual Acuity in Forensic Medicine%"最好矫正日常生活视力"在司法鉴定中的意义

    Institute of Scientific and Technical Information of China (English)

    刘瑞珏

    2011-01-01

    目前我国法医学鉴定实践中有关视力障碍的评价主要是以WHO防盲研究小组于1973年制定的疾病分级标准为依据,所考察的是"最好矫正视力".有时最好矫正视力与日常生活中实际使用的视力可能不一致.WHO于2003年新制定的盲及视力损害分类标准,提出用"日常生活视力"取代"最好矫正视力".在司法鉴定实践中由于伤者的夸大或伪装,"日常生活视力"往往不能反映伤者的真实视力.笔者提出,由鉴定人在"日常生活视力"的基础上评估其"最好矫正日常生活视力",可有助于更公正地进行视功能评定.%At present the sight impairment evaluation in forensic medicine of China is based on the inter national classification of disease by WHO in 1973. The main measured indicator is "best corrected visual acuity". It is different from "presenting distance visual acuity" in some situations. In the new blindness and vision loss classification made by WHO in 2003, "presenting distance visual acuity" took the place of the "best corrected visual acuity". In the practice of forensic medicine, "presenting distance visual acuity" can not reflect the real visual acuity duo to the exaggeration or disguise of the wounded. We suggest to use "the best corrected presenting distance visual acuity" instead of "presenting distance visual acuity" in order to avoid the influences of the exaggeration or disguise of the wounded.

  9. Three-year follow-up of ranibizumab treatment of wet age-related macular degeneration: influence of baseline visual acuity and injection frequency on visual outcomes

    Directory of Open Access Journals (Sweden)

    Razi F

    2016-02-01

    Full Text Available Faraz Razi,1 Adnaan Haq,2 Prabhu Tonne,3 Maharatnam Logendran3 1Department of Paediatrics, Basingstoke and North Hampshire Hospital, Basingstoke, UK; 2Department of Ophthalmology, Leicester General Hospital, Leicester, UK; 3Department of Ophthalmology, Northampton General Hospital, Northampton, UK Purpose: To determine the effect of ranibizumab on visual acuity (VA following a 3-year treatment period for patients diagnosed with wet age-related macular degeneration. To establish whether baseline VA and injection frequency influence visual outcomes. Patients and methods: Retrospective review of 70 patients (76 eyes treated with 0.5 mg intravitreal ranibizumab for 3 consecutive months, and pro re nata thereafter (three + pro re nata protocol, over a 3-year period. VA was measured using Early Treatment Diabetic Retinopathy Study (ETDRS charts at baseline, 12, 24, and 36 months. The number of injections administered at the end of years 1, 2, and 3 were also recorded. Eyes were stratified according to baseline VA, as well as the number of injections administered at the end of year 1. Linear regression analysis determined the relationship between VA and both baseline VA and injection frequency. P<0.05 was considered statistically significant. Results: At 36 months, VA improved by a mean of 5.3 ETDRS letters (P=0.002, with 29% of eyes (n=22 demonstrating a clinically significant improvement in VA (gain of ≥15 ETDRS letters. Improvements in VA from baseline to 36 months were inversely proportional to the baseline VA (R=0.414, P=<0.001. A positive correlation was observed between injection frequency and change in VA from baseline to 36 months (R=0.244, P=0.036. Conclusion: Mean improvement in VA is inversely proportional to baseline VA, and directly proportional to injection frequency. Keywords: long-term results, Lucentis, neovascular AMD

  10. Retinal Oxygen Saturation Correlates With Visual Acuity but Does Not Predict Outcome After Anti-VEGF Treatment in Central Retinal Vein Occlusion.

    Science.gov (United States)

    Jeppesen, Signe Krejberg; Bek, Toke

    2017-05-01

    Occlusion of the central retinal vein (CRVO) is a frequent cause of visual loss. The occlusion induces hypoxia in the retina and the larger retinal veins, but the significance of retinal oxygen saturation for visual acuity at diagnosis and after anti-VEGF treatment for CRVO has not been studied in detail. Retinal oximetry was performed in 91 patients consecutively referred for specialist evaluation of CRVO. The correlation between oxygen saturation in larger retinal vessels and visual acuity at the primary examination and the predictive value of oxygen saturation for visual prognosis after three monthly intravitreal injections with anti-VEGF medication were studied. At referral, the oxygen saturation in larger retinal vessels of the affected eye was significantly higher in arterioles (100.7 ± 1.4% vs. 96.3 ± 0.6%) and significantly lower in venules (37.8 ± 2.6% vs. 58.2 ± 1.3%) than in the unaffected eye (P retinal arterioles (P = 0.002) and a significant positive correlation with the saturation in retinal venules (P = 0.013). Multiple linear regression showed that BCVA, but not oxygen saturations, contributed significantly to predicting visual outcome after three monthly intravitreal injections with VEGF inhibitor. The correlation between retinal oxygen saturation and BCVA at the time of diagnosis of CRVO may help understanding hemodynamic and visual changes in the acute stages of the disease. However, retinal oximetry cannot replace measures of retinal function as a predictive parameter for the visual outcome in CRVO after three monthly intravitreal anti-VEGF injections.

  11. Prevalência de baixa acuidade visual em escolares da rede pública, Sorocaba Prevalence of low visual acuity in public school's students from Brazil

    Directory of Open Access Journals (Sweden)

    Reinaldo José Gianini

    2004-04-01

    Full Text Available OBJETIVO: A baixa acuidade visual tem elevada prevalência e o diagnóstico precoce é necessário pelos danos que pode causar ao desenvolvimento e aprendizado infantis. O estudo realizado objetivou descrever e analisar a prevalência de baixa acuidade visual em escolares da rede de ensino fundamental. MÉTODOS: A partir do diagnóstico da acuidade visual, 9.640 escolares de primeira e quarta séries da rede pública de ensino fundamental de Sorocaba, Estado de São Paulo, no ano 2000, foram analisados e classificados seus registros segundo sexo, série, uso de óculos, área de residência e grau de acesso à assistência médica supletiva. Foram realizados testes de correlação de Pearson e análise de regressão linear. RESULTADOS: A população estudada apresentou prevalência de baixa acuidade visual de 13,1% (IC 95%=12,5-13,8%, sendo significantemente menor no sexo masculino (11,5% quando comparado ao feminino (14,9% - (RP=0,77; significantemente maior nos escolares de primeira série (14,1% quando comparados aos de quarta série (11,5% - (RP=1,22; e significantemente menor em não-usuários de óculos (12,1% quando comparados aos usuários (42,0% - (RP=0,29. Dentre os locais estudados, o bairro de Cajuru apresentou a menor prevalência de baixa acuidade visual (1,8% e o bairro de Vila Sabiá a maior prevalência (32,4%. Foi encontrada correlação positiva, segundo a área de residência entre a proporção de indivíduos que têm acesso à assistência médica supletiva e a proporção de usuários de óculos (r=0,64, pOBJECTIVE: Low visual acuity (VA is an important public health problem due to its high prevalence and because it needs early diagnosis in order to prevent damage in childhood development and apprenticeship. To describe and analyze low visual acuity (VA prevalence among school children METHODS: Once performed the VA test to 1st and 4th grades primary school children data were analyzed by separating students according to

  12. Recovery of neurofilament following early monocular deprivation

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    Timothy P O'Leary

    2012-04-01

    Full Text Available A brief period of monocular deprivation in early postnatal life can alter the structure of neurons within deprived-eye-receiving layers of the dorsal lateral geniculate nucleus. The modification of structure is accompanied by a marked reduction in labeling for neurofilament, a protein that composes the stable cytoskeleton and that supports neuron structure. This study examined the extent of neurofilament recovery in monocularly deprived cats that either had their deprived eye opened (binocular recovery, or had the deprivation reversed to the fellow eye (reverse occlusion. The degree to which recovery was dependent on visually-driven activity was examined by placing monocularly deprived animals in complete darkness (dark rearing. The loss of neurofilament and the reduction of soma size caused by monocular deprivation were both ameliorated equally following either binocular recovery or reverse occlusion for 8 days. Though monocularly deprived animals placed in complete darkness showed recovery of soma size, there was a generalized loss of neurofilament labeling that extended to originally non-deprived layers. Overall, these results indicate that recovery of soma size is achieved by removal of the competitive disadvantage of the deprived eye, and occurred even in the absence of visually-driven activity. Recovery of neurofilament occurred when the competitive disadvantage of the deprived eye was removed, but unlike the recovery of soma size, was dependent upon visually-driven activity. The role of neurofilament in providing stable neural structure raises the intriguing possibility that dark rearing, which reduced overall neurofilament levels, could be used to reset the deprived visual system so as to make it more ameliorable with treatment by experiential manipulations.

  13. 单目视觉里程计/惯性组合导航算法%Algorithm for monocular visual Odometry/SINS integrated navigation

    Institute of Scientific and Technical Information of China (English)

    冯国虎; 吴文启; 曹聚亮; 宋敏

    2011-01-01

    A new algorithm is presented for monocular visual odometry/SINS integrated navigation,in which the camera attitude is provided by the SINS other than visual estimation.The low accuracy of visual attitude estimation which would cause much error for long-range navigation is avoided.After registration and time synchronization,the velocity computation difference between SINS and visual odometry is chosen as observation of integrated navigation.A Kalman filter is used to correct the integrated navigation error including the visual odometry scale factor error.The 22 m indoor and 1412 m outdoor navigation experiments show that the position errors are 3.2% and 4.0% respectively.It can be seen that,compared with Clark's method in which camera attitude estimation is updated periodically with attitude sensors,the proposed algorithm is more accurate and robust with low rate of error growth.The proposed algorithm can be applied to the autonomous navigation of walking robots or wheeled mobile robots in case of serious wheel slip in complex terrain.%提出一种单目视觉里程计/捷联惯性组合导航定位算法.与视觉里程计估计相机姿态不同,惯导系统连续提供相机拍摄时刻对应的三维姿态,克服了单纯由视觉估计相机姿态精度低造成的长距离导航误差大的问题.通过配准和时间同步,用惯导系统解算的速度和视觉里程计计算的速度之差作为组合导航的观测量,采用Kalman滤波修正组合导航系统的误差,同时估计视觉里程计标度因数误差.分别在室内外不同环境下进行了22 m的推车实验和1412m的跑车实验,定位误差分别为3.2%和4.0%.与Clark采用姿态传感器定期更新相机姿态估计结果的方法相比,单目视觉里程计/惯性组合导航定位精度更高,定位误差随距离增长率低,适合步行机器人或轮式移动机器人在复杂地形环境下车轮严重打滑时的自主定位导航.

  14. Agreement between grating acuity at age 1 year and Snellen acuity at age 5.5 years in the preterm child. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

    Science.gov (United States)

    Dobson, V; Quinn, G E; Siatkowski, R M; Baker, J D; Hardy, R J; Reynolds, J D; Trese, M T; Tung, B

    1999-02-01

    To examine the relation between grating acuity at age 1 year and Snellen acuity and grating acuity at 5.5 years, in preterm children with birth weights less than 1251 g. Subjects were participants in the multicenter study of Cryotherapy for Retinopathy of Prematurity. The Teller acuity card (TAC; Vistech Consultants, Dayton, OH) procedure was used to measure monocular grating acuity in children at ages 1 and 5.5 years. Early-treatment diabetic retinopathy study (ETDRS) charts were used to measure the childrens' monocular recognition (Snellen) acuity at age 5.5 years. Data are presented for 575 eyes with measurable TAC grating acuity at 1 year and 111 eyes that had no measurable acuity at 1 year. Among eyes with normal acuity at 1 year, 86.8% showed normal Snellen acuity, and 94.3% showed normal grating acuity at 5.5 years. Among eyes that were blind (i.e., had no measurable TAC grating acuity) at 1 year, 96.8% showed no quantifiable Snellen acuity, and 89.2% showed no quantifiable grating acuity at 5.5 years. Only 2.4% of eyes had acuity in the range between normal and blind at 1 year (i.e., measurable grating acuity Snellen and grating acuity at age 5.5 years, and eyes that had no quantifiable acuity at 1 year remained blind at 5.5 years. Relative position of an eye's acuity score within the normal range was not predictive of the relative position of that eye's later acuity score.

  15. Refractive error, visual acuity and causes of vision loss in children in Shandong, China. The Shandong Children Eye Study.

    Directory of Open Access Journals (Sweden)

    Jian Feng Wu

    Full Text Available PURPOSE: To examine the prevalence of refractive errors and prevalence and causes of vision loss among preschool and school children in East China. METHODS: Using a random cluster sampling in a cross-sectional school-based study design, children with an age of 4-18 years were selected from kindergartens, primary schools, and junior and senior high schools in the rural Guanxian County and the city of Weihai. All children underwent a complete ocular examination including measurement of uncorrected (UCVA and best corrected visual acuity (BCVA and auto-refractometry under cycloplegia. Myopia was defined as refractive error of ≤-0.5 diopters (D, high myopia as ≤ -6.0D, and amblyopia as BCVA ≤ 20/32 without any obvious reason for vision reduction and with strabismus or refractive errors as potential reasons. RESULTS: Out of 6364 eligible children, 6026 (94.7% children participated. Prevalence of myopia (overall: 36.9 ± 0.6%;95% confidence interval (CI:36.0,38.0 increased (P<0.001 from 1.7 ± 1.2% (95%CI:0.0,4.0 in the 4-years olds to 84.6 ± 3.2% (95%CI:78.0,91.0 in 17-years olds. Myopia was associated with older age (OR:1.56;95%CI:1.52,1.60;P<0.001, female gender (OR:1.22;95%CI:1.08,1.39;P = 0.002 and urban region (OR:2.88;95%CI:2.53,3.29;P<0.001. Prevalence of high myopia (2.0 ± 0.2% increased from 0.7 ± 0.3% (95%CI:0.1,1.3 in 10-years olds to 13.9 ± 3.0 (95%CI:7.8,19.9 in 17-years olds. It was associated with older age (OR:1.50;95%CI:1.41,1.60;P<0.001 and urban region (OR:3.11;95%CI:2.08,4.66;P<0.001. Astigmatism (≥ 0.75D (36.3 ± 0.6%;95%CI:35.0,38.0 was associated with older age (P<0.001;OR:1.06;95%CI:1.04,1.09, more myopic refractive error (P<0.001;OR:0.94;95%CI:0.91,0.97 and urban region (P<0.001;OR:1.47;95%CI:1.31,1.64. BCVA was ≤ 20/40 in the better eye in 19 (0.32% children. UCVA ≤ 20/40 in at least one eye was found in 2046 (34.05% children, with undercorrected refractive error as cause in 1975 (32.9% children. Amblyopia

  16. Localization of monocular stimuli in different depth planes.

    Science.gov (United States)

    Shimono, Koichi; Tam, Wa James; Asakura, Nobuhiko; Ohmi, Masao

    2005-09-01

    We examined the phenomenon in which two physically aligned monocular stimuli appear to be non-collinear when each of them is located in binocular regions that are at different depth planes. Using monocular bars embedded in binocular random-dot areas that are at different depths, we manipulated properties of the binocular areas and examined their effect on the perceived direction and depth of the monocular stimuli. Results showed that (1) the relative visual direction and perceived depth of the monocular bars depended on the binocular disparity and the dot density of the binocular areas, and (2) the visual direction, but not the depth, depended on the width of the binocular regions. These results are consistent with the hypothesis that monocular stimuli are treated by the visual system as binocular stimuli that have acquired the properties of their binocular surrounds. Moreover, partial correlation analysis suggests that the visual system utilizes both the disparity information of the binocular areas and the perceived depth of the monocular bars in determining the relative visual direction of the bars.

  17. Tactile acuity charts: a reliable measure of spatial acuity.

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    Patrick Bruns

    Full Text Available For assessing tactile spatial resolution it has recently been recommended to use tactile acuity charts which follow the design principles of the Snellen letter charts for visual acuity and involve active touch. However, it is currently unknown whether acuity thresholds obtained with this newly developed psychophysical procedure are in accordance with established measures of tactile acuity that involve passive contact with fixed duration and control of contact force. Here we directly compared tactile acuity thresholds obtained with the acuity charts to traditional two-point and grating orientation thresholds in a group of young healthy adults. For this purpose, two types of charts, using either Braille-like dot patterns or embossed Landolt rings with different orientations, were adapted from previous studies. Measurements with the two types of charts were equivalent, but generally more reliable with the dot pattern chart. A comparison with the two-point and grating orientation task data showed that the test-retest reliability of the acuity chart measurements after one week was superior to that of the passive methods. Individual thresholds obtained with the acuity charts agreed reasonably with the grating orientation threshold, but less so with the two-point threshold that yielded relatively distinct acuity estimates compared to the other methods. This potentially considerable amount of mismatch between different measures of tactile acuity suggests that tactile spatial resolution is a complex entity that should ideally be measured with different methods in parallel. The simple test procedure and high reliability of the acuity charts makes them a promising complement and alternative to the traditional two-point and grating orientation thresholds.

  18. Monocular Vision: Occupational Limitations and Current Standards

    Science.gov (United States)

    2011-03-01

    Kumagai, J. K., Williams, S., and Kline, D. (2005), Vision standards for aircrew: Visual acuity for pilots, (DRDC-TORONTO-CR-2005-142), Greenley ...Canadian Forces aircrew, (DRDC-TORONTO-CR-2006-255), Greenley and Associate Inc., Ottawa. Lövsund, P., Hedin, A., and Törnros, J. (1991), Effects...Williams, S., Casson, E., Brooks, J., Greenley , M., and Nadeau, J. (2003), Visual acuity standard for divers, Greenley & Associates Incorporated

  19. Evaluation and analysis of children's graphic visual acuity chart and Teller visual acuity cards on infants%儿童图形视力表与Teller视敏锐度卡在婴幼儿视力检测中应用分析

    Institute of Scientific and Technical Information of China (English)

    吴丽波; 姚晶磊; 成娟娟; 焦永红

    2014-01-01

    Objective To evaluate the feasibility and reliability of visual assessment system of Children's Graphic Visual Acuity Chart and Teller Visual Acuity Cards on infants.Methods A total of 185 patients were included in this study from Strabismus and Amblyopia Out-patient Department,Beijing Tongren Hospital in 2012.Among those,118 eyes were checked in 59 infants from 2 to 3 years old with Children's Graphic Visual Acuity Chart,252 eyes were checked in 126 infants from 5 months to 2 years old with Teller Visual Acuity Cards.They were divided into 10 groups according to their age sequence,and every 2 months for one group.The visual acuity was recorded and results were analyzed statistically.Results Visual acuity was obtained with Children's Graphic Visual Acuity Chart,and the results were as follows:0.1-0.2 accounted for 14.41% (17 in 118),0.3-0.5,64.40% (76 in 118),0.6 21.19% (25 in 118); Similarly,visual acuity with Teller Visual Acuity Cards were obtained,the results were as follows:13cy/cm accounted for 21.43% (54 in 252),4.8-9.8cy/cm 20.63% (52 in 252),1.3-3.2cy/cm 42.86% (108 in 252),0.86cy/cm 10.71% (27 in 252),0.43cy/cm 4.37% (11 in 252).Conclusions Children's graphic visual acuity chart and Teller visual acuity cards are feasible and reliable visual assessment system on 5 months to 3 years old children.Compared with conventional test,the two visual assessment systems can find abnormal low vision earlier.At the same time,these visual assessment systems can be developed for early intervention and treatment programs on congenital eye disorders in infants with low vision.%目的 探讨儿童图形视力表、Teller视敏锐度卡在婴幼儿视力检测中的可行性和可靠性.方法 对2010年1~12月在北京同仁医院眼科斜弱视门诊就诊的185例患儿,分别使用儿童图形视力表检测2~3岁患儿59例118只眼,用Teller视敏锐度卡检测5个月至2岁患儿126例252只眼.每2个月龄为一组,共分为10组进行视力

  20. Monocular transparency generates quantitative depth.

    Science.gov (United States)

    Howard, Ian P; Duke, Philip A

    2003-11-01

    Monocular zones adjacent to depth steps can create an impression of depth in the absence of binocular disparity. However, the magnitude of depth is not specified. We designed a stereogram that provides information about depth magnitude but which has no disparity. The effect depends on transparency rather than occlusion. For most subjects, depth magnitude produced by monocular transparency was similar to that created by a disparity-defined depth probe. Addition of disparity to monocular transparency did not improve the accuracy of depth settings. The magnitude of depth created by monocular occlusion fell short of that created by monocular transparency.

  1. Correlation Between the Findings of Optical Coherent Retinal Tomography (OCT), Stereo Biomicroscopic Images from Fundus of an Eye and Values from Visual Acuity of Diabetic Macular Edema

    Science.gov (United States)

    Nisic, Faruk; Turkovic, Samir; Mavija, Milka; Jovanovic, Nina; Alimanovic, Emina Halilovic-

    2014-01-01

    Introduction: Diabetic maculopathy is the major cause of reduced visual acuity in patients with non-proliferative diabetic retinopathy and occurs on average in 29% of patients who have diabetes for 20 or more years. Aim: The aim of this study is to re examine the correlation between the findings of optical coherence retinal tomography, stereo bio-microscopic images from fundus of an eye and values from visual acuity of diabetic macular edema. In addition, the aim is to show the importance of various ophthalmic tests for establishing diagnosis in time. Material and methods: The research sample consisted of 90 subjects-patients from Cabinet for photographic documentation, fluorescein angiography and laser photocoagulation in Department of Ophthalmology at the University Clinical Centre in Sarajevo. The study was a one-year long, prospective, clinical study. Results: Research has shown a positive correlation between the various tests that are applied for the diagnosis of diabetic macular edema. Accurate and early diagnosis is of great importance for the treatment in time of this disease by applying laser photocoagulation, intravitreal injections of Anti-VEGF drugs or surgical treatment by Pars Plana Vitrectomy. PMID:25395723

  2. Myopia prevention, near work, and visual acuity of college students: integrating the theory of planned behavior and self-determination theory.

    Science.gov (United States)

    Chan, Derwin King-Chung; Fung, Ying-Ki; Xing, Suxuan; Hagger, Martin S

    2014-06-01

    There has been little research examining the psychological antecedents of safety-oriented behavior aimed at reducing myopia risk. This study utilizes self-determination theory (SDT) and the theory of planned behavior (TPB) to understand the role of motivational and social-cognitive factors on individuals' near-work behavior. Adopting a prospective design, undergraduate students (n = 107) completed an initial questionnaire based on SDT in week 1, a second questionnaire containing measures of TPB variables in week 2, and objective measures of reading distance and visual acuity in week 6. The data were analyzed by variance-based structural equation modeling. The results showed that perceived autonomy support and autonomous motivation from SDT significantly predicted attitude, subjective norm, and perceived behavioral control from the TPB. These social-cognitive factors were significantly associated with intention and intention significantly predicted reading distance. The relationships in the model held when controlling for visual acuity. In conclusion, the integrated model of SDT and the TPB may help explain myopia-preventive behaviors.

  3. Visual Acuity Before and After Treatment in Patients with Chemical Injuries at the National Eye Center, Cicendo Eye Hospital, Bandung from 2010 to 2011

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    Endi Pramudya Laksana

    2015-09-01

    Full Text Available Background: Chemical trauma is one of the emergency cases in ophthalmology since it can lead to severe, permanent blindness if not immediately treated. This study aimed to reveal pre- and post-therapy visual acuity on patients with chemical trauma at theNational Eye Center, Cicendo Eye Hospital, Bandung. Methods: This study was performed on 40 patients’ medical records from the National Eye Center, Cicendo Eye Hospital Bandung from January 2010 to January 2011 as secondary data, using the descriptive retrospective method. The data were divided into two groups: acid and alkali trauma. The collected data were analyzed and presented in tables. Results: Chemical trauma cases were mostly caused by caustic soda (17/40 whereas the least were caused by vinegar (3/40 and commonly occurred on adult patients in the right eye on alkali trauma. Patients with chemical trauma generally had normal eyesight before therapy.The number of patients with acid and alkali trauma who experienced improved eyesight after therapy alkali were similar (3 patients while worsening symptoms occurred in one patient with alkali chemical trauma from mild to medium low vision. Conclusions: There are some improvements of visual acuity after treatment in patients with chemical injuries.

  4. The effect of intravitreal administration of bevacizumab on macular edema and visual acuity in age-related macular degeneration with subfoveolar choroidal neovascularisation

    Directory of Open Access Journals (Sweden)

    Ristić Dragana

    2013-01-01

    Full Text Available Background/Aim. Age-related macular degeneration (AMD is a leading cause of the loss of central visual acuity in population older than 70 years. We can distinguish wet and dry form of AMD. The aim of the study was to present our early results in treatment of the wet (neovascular form of AMD with intravitreal administration of bevacizumab. Methods. The study included 39 patients. Each patient underwent a complete ophthalmological examination, fluorescein angiography (FA and optical coherence tomography (OCT. All the patients received 1.25 mg of intravitreal bevacizumab (0.05 mL of commercial phial of Avastin®. The total of three doses was given with a one-month interval between doses. Results. Among 39 patients, 24 were women and 15 men. The average best corrected visual acuity (BCVA was improved from 0.09 before the therapy to 0.24 after the administration of all the three doses of bevacizumab (p < 0.001. The average central macular thickness (CMT measured by OCT was improved from 474 μm in the beginning to 341 μm after the administration of all the three doses of the drug (p < 0.001. There were no side effects. Conclusions. Our short-term experience indicates that intravitreal administration of three doses of bevacizumab in one-month intervals between the doses leads to a significant reduction of macular edema and improvement of BCVA in patients with neovascular AMD.

  5. Subthreshold Micropulse Photocoagulation for Persistent Macular Edema Secondary to Branch Retinal Vein Occlusion including Best-Corrected Visual Acuity Greater Than 20/40

    Directory of Open Access Journals (Sweden)

    Keiji Inagaki

    2014-01-01

    Full Text Available To assess the efficacy of subthreshold micropulse diode laser photocoagulation (SMDLP for persistent macular edema secondary to branch retinal vein occlusion (BRVO, including best-corrected visual acuity (BCVA > 20/40, thirty-two patients (32 eyes with macular edema secondary to BRVO were treated by SMDLP. After disease onset, all patients had been followed for at least 6 months prior to treatment. Baseline Snellen visual acuity was used to categorize the eyes as BCVA ≤ 20/40 (Group I or BCVA > 20/40 (Group II. Main outcome measures were reduction in central macular thickness (CMT in optical coherence tomography (OCT and BCVA at 6 months. In the total subject-pool at 6 months, BCVA had not changed significantly but CMT was significantly reduced. Group I exhibited no significant change in CMT at 3 months but exhibited significant reductions at 6 and 12 months. Group II exhibited a marginally significant reduction in CMT at 3 months and a significant reduction at 6 months. In patients with persistent macular edema secondary to BRVO, SMDLP appears to control macular edema with minimal retinal damage. Our findings suggest that SMDLP is an effective treatment method for macular edema in BRVO patients with BCVA > 20/40.

  6. Effects of Mild Hypercapnia During Head-Down Bed Rest on Ocular Structures, Cerebral Blood Flow, aud Visual Acuity in Healthy Human Subjects

    Science.gov (United States)

    Laurie, S. S.; Taibbi, G.; Lee, S. M. C.; Martin, D. S.; Zanello, S.; Ploutz-Snyder, R.; Hu, X.; Stenger, M. B.; Vizzeri, G.

    2014-01-01

    The cephalad fluid shift induced by microgravity has been hypothesized to cause an elevation in intracranial pressure (ICP) and contribute to the development of the Visual Impairment/Intracranial Pressure (VIIP) syndrome, as experienced by some astronauts during long-duration space flight. Elevated ambient partial pressure of carbon dioxide (PCO2) on ISS may also raise ICP and contribute to VIIP development. We seek to determine if the combination of mild CO2 exposure, similar to that occurring on the International Space Station, with the cephalad fluid shift induced by head-down tilt, will induce ophthalmic and cerebral blood flow changes similar to those described in the VIIP syndrome. We hypothesize that mild hypercapnia in the head-down tilt position will increase choroidal blood volume and cerebral blood flow, raise intraocular pressure (IOP), and transiently reduce visual acuity as compared to the seated or the head-down tilt position without elevated CO2, respectively.

  7. Rapid recovery from the effects of early monocular deprivation is enabled by temporary inactivation of the retinas

    Science.gov (United States)

    Fong, Ming-fai; Mitchell, Donald E.; Duffy, Kevin R.; Bear, Mark F.

    2016-01-01

    A half-century of research on the consequences of monocular deprivation (MD) in animals has revealed a great deal about the pathophysiology of amblyopia. MD initiates synaptic changes in the visual cortex that reduce acuity and binocular vision by causing neurons to lose responsiveness to the deprived eye. However, much less is known about how deprivation-induced synaptic modifications can be reversed to restore normal visual function. One theoretically motivated hypothesis is that a period of inactivity can reduce the threshold for synaptic potentiation such that subsequent visual experience promotes synaptic strengthening and increased responsiveness in the visual cortex. Here we have reduced this idea to practice in two species. In young mice, we show that the otherwise stable loss of cortical responsiveness caused by MD is reversed when binocular visual experience follows temporary anesthetic inactivation of the retinas. In 3-mo-old kittens, we show that a severe impairment of visual acuity is also fully reversed by binocular experience following treatment and, further, that prolonged retinal inactivation alone can erase anatomical consequences of MD. We conclude that temporary retinal inactivation represents a highly efficacious means to promote recovery of function. PMID:27856748

  8. Correcting Finger Counting to Snellen Acuity.

    Science.gov (United States)

    Karanjia, Rustum; Hwang, Tiffany Jean; Chen, Alexander Francis; Pouw, Andrew; Tian, Jack J; Chu, Edward R; Wang, Michelle Y; Tran, Jeffrey Show; Sadun, Alfredo A

    2016-10-01

    In this paper, the authors describe an online tool with which to convert and thus quantify count finger measurements of visual acuity into Snellen equivalents. It is hoped that this tool allows for the re-interpretation of retrospectively collected data that provide visual acuity in terms of qualitative count finger measurements.

  9. Daily mixed visual experience that prevents amblyopia in cats does not always allow the development of good binocular depth perception.

    Science.gov (United States)

    Mitchell, Donald E; Kennie, Jan; Schwarzkopf, D Samuel; Sengpiel, Frank

    2009-05-21

    Kittens reared with mixed daily visual input that consists of episodes of normal (binocular) exposure followed by abnormal (monocular) exposure can develop normal visual acuity in both eyes if the length of the former exposure exceeds a critical amount. However, later studies of the tuning of cells in primary visual cortex of animals reared in this manner revealed that their responses to interocular differences in phase were not reliable suggesting that their binocular depth perception may not be normal. We examined this possibility in 3 kittens reared with mixed daily visual exposure (2 hrs binocular vision followed by 5 hrs monocular exposure) that allowed development of normal visual acuity in both eyes. Measurements made of the threshold differences in depth that could be perceived under monocular and binocular viewing revealed a 10-fold superiority of binocular over monocular depth thresholds in one animal while the depth thresholds of the other two animals were poor and there was no binocular superiority. Thus, there was evidence that only one animal possessed stereopsis while the other two were likely stereoblind. While 2 hrs of daily binocular vision protected against the development of amblyopia, the poor outcome with respect to stereopsis points to the need for additional measures to promote binocular vision.

  10. Investigation and analysis on visual acuity situation among students in a college%某校大学生视力状况调查分析

    Institute of Scientific and Technical Information of China (English)

    胡贵贤; 张喆

    2016-01-01

    Objective To investigate the visual acuity in different grades of students in our college ,and to analyzes the reasons for the visual acuity decrease in college students to provide a reference for health care of college students. Methods A total of 5 351 students(4 804 female students,547 male students) of grade 2013,2012,2011 were performed the routine binocu-lar visual acuity detection by adopting the national standard logarithmic eye chart. Results The overall detection rate of poor eyesight among students in our college was 52.79%,in which,mild,moderate,and severe poor vision detection rates were 26.62%, 25.45%and 47.93%respectively. The poor vision rates in 3 grades of students were 32.81%,60.67%and 68.19%respectively. Conclusion The poor vision rate is gradually increased with the grade increase ,namely the vision presents a decreasing trend during college period.%目的通过对本校不同年级学生进行视力状况调查,分析大学生视力下降的原因,为在校大学生的健康保健提供参考。方法对本校2013级、2012级、2011级5351名学生(其中女生4804名,男生547名)采用国家标准对数视力表,常规对两眼分别进行检查。结果本校学生总的视力不良检出率为52.79%,其中轻、中、重度视力不良检出率分别为26.62%,25.45%,47.93%。3个年级学生的视力不良率分别为32.81%、60.67%、68.19%。结论视力不良率随年级的增加而逐渐增加,即学生在大学期间视力呈下降趋势。

  11. Factors Contributing to Discrepancy Between Visual Acuity Fractions Derived From a Snellen Chart and Letter Scores on the Early Treatment Diabetic Retinopathy Study Chart.

    Science.gov (United States)

    Chen, Fred K; Agelis, Lillian Evangelia; Peh, Khaik K; Teong, Joanne; Wong, Evan Norman Xi Ming

    2014-01-01

    To report factors influencing the relationship between visual acuity (VA) fractions measured on Snellen chart and letter scores on the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. This was a retrospective review from a single ophthalmology outpatient clinic. All patients had routine consecutive VA testing in the right eye using a Snellen chart (1-6 m) and the ETDRS chart (4 m and/or 1 m), by the same optometrist, using a standardized testing protocol for each chart. Both acuity fractions and letter scores were converted to their equivalent logarithm of minimum angle of resolution (logMAR) for comparison. Multiple regression analysis was performed. A total of 237 patients with a wide range of ocular disease and VAs were enrolled. Mean age was 63 years (range, 18-95 years). Recorded VA (logMAR) was better on Snellen chart by a mean (95% limits of agreement) of -0.07 (-0.33 to +0.18, P Snellen and ETDRS charts was nonuniform across VA range. This has implications on interpretation of published studies converting Snellen fractions to logMAR for analysis and reporting of VA outcomes.

  12. Comparação entre acuidade visual e photoscreening como métodos de triagem visual para crianças em idade escolar Comparison between visual acuity and photoscreening used like visual screening methods for scholar aged children

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    Roberta Lílian Fernandes de Sousa

    2012-12-01

    Full Text Available OBJETIVO: Avaliar a sensibilidade do aparelho photoscreener na detecção de alterações oculares em crianças informantes, comparando os dados à acuidade visual obtida pela tabela E de Snellen. MÉTODOS: Foram avaliadas 500 crianças de idades entre 5 e 12 anos, de escola do município de Botucatu, estado de São Paulo. As crianças foram submetidas ao teste de acuidade visual pela tabela E de Snellen e foram fotografadas utilizando-se o aparelho photoscreenerTM system model MTI-PS100, seguindo-se a análise das fotos obtidas. RESULTADOS: Houve concordância negativa (criança com boa acuidade visual e teste negativo com o photoscreener em 81,0%; concordância positiva (acuidade visual alterada e teste positivo em 7,6% e não houve concordância de resultados em 11,0% dos casos. CONCLUSÃO: A avaliação comparativa entre o método da acuidade visual pela tabela E de Snellen e o photocreener para detecção de problemas visuais mostrou alta concordância. Os autores sugerem entretanto, a triagem usando tabelas de acuidade visual quando se trata de crianças informantes, devido aos custos com o aparelho.PURPOSE: To evaluate the sensitivity of the photoscreener equipment to detect ocular changes in informative children comparing with the data obtained by the E Snellen´s table. METHODS: We evaluated 500 children between 5 and 12 years old, from a school of Botucatu city, São Paulo state. The children were submitted to a visual acuity test using the Snellen´s E Table and were photographed with the photoscreenerTM system model MTI-PS100, following the photos' analyze. RESULTS: There were negative agreement (children with a good visual acuity and a negative test with the Photoscreener in 81.0%; positive agreement (children without a good visual acuity and a positive test in 7.6% and there was no agreement of the results in 11.0% (9 of the cases. CONCLUSION: The comparative analysis between the visual acuity test using the Snellen's E table and

  13. 新型对数视力表与“C”形对数视力表的一致性与稳定性分析%Concordance and reliability of new logMAR visual acuity chart and Landolt C logarithmical visual acuity chart

    Institute of Scientific and Technical Information of China (English)

    李刚

    2013-01-01

    Objective To evaluate new logMAR visual acuity chart's test-retest reliability and concordance with "C" logarithm visual acuity chart.Methods This was a cross-sectional study.Measurements using two versions of each chart design were obtained on the right eye of 48 high school students.The test-retest reliability was analyzed by intraclass correlation coefficient (ICC) and Cronbach's Alpha coefficients,and Bland-Altman plots were used to compare the agreement between the two charts.Results The Cronbach's Alpha coefficients of "C" logarithm visual acuity chart was more than 0.8,and the ICC was near 0.9.For the new logMAR visual acuity chart,the Cronbach's Alpha coefficients was near 0.8,and the ICC was more than 0.75.The Bland-Altman plots displayed relatively good agreement between the two charts.The 95% limits of agreement were 0.173 to -0.133 logMAR and 0.198 to-0.116 logMAR for the test and retest measurements respectively.Conclusion In healthy eyes,the new logMAR visual acuity chart has high test-retest reliability and good concordance with Landolt C logarithmical visual acuity chart.%目的 评价新型对数视力表与具有8个方向视标选项的“C”形对数视力表之间的一致性与稳定性.方法 横断面研究.对48例应届高中毕业生分别进行新型对数视力表与“C”形对数视力表的视力检查,采用组内相关系数(ICC)和Cronbach's Alpha系数分析视力测量结果的重复性,采用Bland-Altman分析一致性.结果 “C”形对数视力表Cronbach's Alpha系数在0.8以上,ICC接近0.9,新型对数视力表Cronbach's Alpha系数接近0.8,ICC>0.75,均显示较好的重测稳定性.2种视力表第1次和第2次视力测量均具有较好的一致性,95%一致性界限分别为(0.173,-0.133)logMAR和(0.198,-0.116)logMAR.结论 新型对数视力表检查结果稳定,和“C”形对数视力表一致性较好.

  14. Visual acuity in an Iranian cohort of patients with type 2 diabetes: the role of nephropathy and ischemic heart disease

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    Negar Horri

    2011-01-01

    Conclusions: The factors related to retinopathy play a role in affecting the degree of visual impairment in diabetic patients. Therefore, controlling risk factors can be useful in decreasing impairment of vision and blindness.

  15. Current smoking is associated with a poor visual acuity improvement after intravitreal ranibizumab therapy in patients with exudative age-related macular degeneration.

    Science.gov (United States)

    Lee, Sangmoon; Song, Su Jeong; Yu, Hyeong Gon

    2013-05-01

    In this study, the risk factors that may influence visual improvement after intravitreal ranibizumab (IVR) treatment for exudative age-related macular degeneration (AMD) were examined. From 2008 to 2012, 420 patients (448 eyes) with exudative AMD were prospectively registered at Seoul National University Hospital. From this group of patients, 125 eyes were included in this study. All patients were treated with 3 consecutive IVR injections. The visual acuity (VA) was evaluated at baseline and 1 month after the third ranibizumab injection. To evaluate the risk factors associated with VA improvement after IVR, patient demographic data and systemic risk factors were analyzed. Patients were divided into a poor VA improvement group and a good VA improvement group, with reference to the median visual improvement in all eyes. Among 125 eyes, 66 eyes (52.8%) were included in the responder group and 59 eyes (47.2%) in the non-responder group. The median VA improvement after 3 monthly ranibizumab injections was -0.05 logMAR. Multivariate analyses revealed that current smoking (adjusted OR, 7.540; 95% CI, 1.732-32.823) was independently associated with poor VA improvement after IVR treatment for exudative AMD. In conclusion, cigarette smoking is an independent risk factor for lower VA gains with IVR treatment for exudative AMD.

  16. Visual abilities in two raptors with different ecology.

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    Potier, Simon; Bonadonna, Francesco; Kelber, Almut; Martin, Graham R; Isard, Pierre-François; Dulaurent, Thomas; Duriez, Olivier

    2016-09-01

    Differences in visual capabilities are known to reflect differences in foraging behaviour even among closely related species. Among birds, the foraging of diurnal raptors is assumed to be guided mainly by vision but their foraging tactics include both scavenging upon immobile prey and the aerial pursuit of highly mobile prey. We studied how visual capabilities differ between two diurnal raptor species of similar size: Harris's hawks, Parabuteo unicinctus, which take mobile prey, and black kites, Milvus migrans, which are primarily carrion eaters. We measured visual acuity, foveal characteristics and visual fields in both species. Visual acuity was determined using a behavioural training technique; foveal characteristics were determined using ultra-high resolution spectral-domain optical coherence tomography (OCT); and visual field parameters were determined using an ophthalmoscopic reflex technique. We found that these two raptors differ in their visual capacities. Harris's hawks have a visual acuity slightly higher than that of black kites. Among the five Harris's hawks tested, individuals with higher estimated visual acuity made more horizontal head movements before making a decision. This may reflect an increase in the use of monocular vision. Harris's hawks have two foveas (one central and one temporal), while black kites have only one central fovea and a temporal area. Black kites have a wider visual field than Harris's hawks. This may facilitate the detection of conspecifics when they are scavenging. These differences in the visual capabilities of these two raptors may reflect differences in the perceptual demands of their foraging behaviours.

  17. Comparative evaluation of teller and cardiff acuity tests in normals and unilateral amblyopes in under-two-year-olds

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    Sharma Pradeep

    2003-01-01

    Full Text Available Purpose: To compare and evaluate Teller Acuity Cards (TAC and Cardiff Acuity Cards (CAC to assess vision in children below the age of two. Methods: The study evaluated TAC and CAC to assess visual acuity in 90 normal children divided into three age groups, 0 - 6 months (group I, 6 - 12 months (group II and 12 - 24 months (group III. 30 cases of unilateral amblyopiogenic conditions, 10 cases each of unilateral refractive error, unilateral esotropia, and unilateral cataract, were also examined. Trained optometrists carried out binocular testing followed by monocular testing, and recorded the test time in each case. Results: The mean visual acuity (in Snellen units and standard deviation (in octaves in the three age groups of normal children, I, II, III respectively were 6/44 ± 0.54, 6/21 ± 0.37 and 6/21 ± 0.41 (binocularly by TAC and 6/46 ± 0.80, 6/21 ± 0.59 and 6/14.5 ± 0.84 (binocularly by CAC. Although the time taken for testing with CAC was less, its coefficient of variance was greater for all age groups as compared to TAC. Diminution of visual acuity could be assessed correctly by both the tests in cases of strabismus and cataract, but not in some cases of refractive error. Conclusion: CAC is a useful and child-friendly test. It can be used clinically but may miss some cases of visually significant refractive errors. TAC is a more dependable test to assess amblyopiogenic conditions despite the use of gratings.

  18. Monocular alignment in different depth planes.

    Science.gov (United States)

    Shimono, Koichi; Wade, Nicholas J

    2002-04-01

    We examined (a) whether vertical lines at different physical horizontal positions in the same eye can appear to be aligned, and (b), if so, whether the difference between the horizontal positions of the aligned vertical lines can vary with the perceived depth between them. In two experiments, each of two vertical monocular lines was presented (in its respective rectangular area) in one field of a random-dot stereopair with binocular disparity. In Experiment 1, 15 observers were asked to align a line in an upper area with a line in a lower area. The results indicated that when the lines appeared aligned, their horizontal physical positions could differ and the direction of the difference coincided with the type of disparity of the rectangular areas; this is not consistent with the law of the visual direction of monocular stimuli. In Experiment 2, 11 observers were asked to report relative depth between the two lines and to align them. The results indicated that the difference of the horizontal position did not covary with their perceived relative depth, suggesting that the visual direction and perceived depth of the monocular line are mediated via different mechanisms.

  19. Improvement of uncorrected visual acuity (UCVA and contrast sensitivity (UCCS with perceptual learning and transcranial random noise stimulation (tRNS in individuals with mild myopia

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    Rebecca eCamilleri

    2014-10-01

    Full Text Available Perceptual learning has been shown to produce an improvement of visual acuity (VA and contrast sensitivity (CS both in subjects with amblyopia and refractive defects such as myopia or presbyopia. Transcranial random noise stimulation (tRNS has proven to be efficacious in accelerating neural plasticity and boosting perceptual learning in healthy participants. In this study we investigated whether a short behavioural training regime using a contrast detection task combined with online tRNS was as effective in improving visual functions in participants with mild myopia compared to a two-month behavioural training regime without tRNS (Camilleri et al., 2014. After two weeks of perceptual training in combination with tRNS, participants showed an improvement of 0.15 LogMAR in uncorrected VA (UCVA that was comparable with that obtained after eight weeks of training with no tRNS, and an improvement in uncorrected CS (UCCS at various spatial frequencies (whereas no UCCS improvement was seen after eight weeks of training with no tRNS. On the other hand, a control group that trained for two weeks without stimulation did not show any significant UCVA or UCCS improvement. These results suggest that the combination of behavioural and neuromodulatory techniques can be fast and efficacious in improving sight in individuals with mild myopia.

  20. Avaliação da acuidade visual em escolares da 1ª série do ensino fundamental Assessment of visual acuity in pupils of elementary schools

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    José Aparecido Granzoto

    2003-01-01

    Full Text Available RESUMO OBJETIVOS: Estudar a importância dos programas de promoção de saúde ocular na avaliação da acuidade visual para detecção precoce de distúrbios oftalmológicos, em programas de promoção da saúde ocular. MÉTODOS: Estudo descritivo de delineamento transversal. Foram avaliados escolares primários, pertencentes a 21 escolas municipais de Pelotas, RS, por meio de questionário com as variáveis: sexo e idade, percepção da própria visão, uso de óculos ou lentes de contato e medida da acuidade visual (AV pela escala de Snellen. Os alunos com AV PURPOSE: To study the meaning of visual acuity evaluation in ocular health programs for the early detection of ophthalmic disorders. METHODS: In this cross-sectional descriptive survey, schoolchildren of 21 elementary schools of Pelotas, RS were evaluated. Age, sex, awareness about own vision, wearing glasses or contact lenses were recorded by application of a questionnaire. Visual acuity (VA was assessed with Snellen E optotypes. Children with VA< 0.7 or symptoms of eye problems were referred to the specialist for a detailed ophthalmologic examination. RESULTS: Of the 1502 schoolchildren included in the research, 774 (51.5% were male. The majority, 1328 (88.41%, was aged from 6 to 8 years. Approximately 90% of the children believed to have a good vision. VA of 227 children (15.1% was below standard. Of them, 124 (54.6% were female. Of those who thought they had no visual problem, 193 (14.23% were referred to an ophthalmologist. CONCLUSION: Results of this study stress the importance of VA screening. The main purpose of ocular health campaigns consists of helping children to develop their full potentialities.

  1. 日常生活视力在儿童近视防治实践中的应用%Application of presenting visual acuity in the prevention and control of myopia in children

    Institute of Scientific and Technical Information of China (English)

    何鲜桂; 赵蓉; 陆丽娜; 朱剑锋

    2012-01-01

    Objective To evaluate the role of presenting visual acuity in the prevention and control of childhood myopia. Methods With stratified random cluster sampling, 41 243 children of grade 1 to 9 from 55 schools situated in 8 districts in Shanghai were selected to conduct the uncorrected visual acuity. In children who were wearing glasses, visual acuity was measured both with and without spectacles. The analyses of presenting visual acuity were based on worse and better eye vision, respectively. Re-sults Of the 41 243 children, the moderately visually impaired and the mildly impaired of presenting were 11.6% and 2. 3% , respectively. As the grades increased, the rate of visually impaired in children increased,to grade 4 it maintained at about 17%. Uncorrected visual acuity and presenting visual acuity worse than 4. 9 were 21 595 (52.4% ) and 15 717(38. 1% ) children, respectively. In comparison with the uncorrected visual acuity, presenting visual acuity as an indicator for screening could help 5 878 (27. 2% ) children avoid having received appropriate refraction correction and being referred to the clinic again. Conclusion The use of presenting visual acuity as an indicator could help us to know the daily visual quality among children, and improve the efficiency of myopia screening. It may be a valuable indicator for the prevention and control of myopia in children.%目的 探讨日常生活视力指标在儿童近视防治实践中的应用,为在学校卫生领域正确评价儿童视力状况提供依据.方法 整群抽取上海市8个区55所中小学校一~九年级41 243名学生,行裸眼远视力检查,戴镜者同时检查戴镜视力,分别以较好眼和较差眼分析日常生活视力实践应用情况.结果 受检人群较好眼日常生活视力良好有24461名(59.3%),视力轻度受损4779名(11.6%),视力中度损害934名(2.3%);视力受损率(≤4.7)随年级增长而上升,上升趋势至四年级以上趋于平缓,保持在17

  2. Visual dysfunction among former microelectronics assembly workers.

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    Mergler, D; Huel, G; Bowler, R; Frenette, B; Cone, J

    1991-01-01

    Although known neurotoxins with potential ophthalmotoxic properties are commonly used in microelectronics assembly, there has been no systematic study of visual disturbances among past or present workers in this industry. The objective of the present study was to compare visual functions, using a matched-pair design, between former workers from a microelectronics plant and a local reference population. From an initial population of 180 former workers and 157 potential referents, 54 pairs were matched for age (+/- 3 y), education (+/- 2 y), sex, ethnic origin, and number of children. Near and far visual acuity, chromatic discrimination, and near contrast sensitivity were assessed monocularly. Paired comparisons (Signed-rank Wilcoxon test) revealed that the former microelectronics workers had significantly lower contrast sensitivity, particularly in the intermediate frequencies, independently of near visual acuity loss. There were no differences for far visual acuity in both eyes. Even though near visual acuity and color vision were compromised among the former workers, the differences were only significant for one eye, as was the prevalence of acquired dyschromatopsia (chi-square for matched pairs, p less than .001). These findings suggest a pattern of contrast sensitivity deficits consistent with impairment to foveal and/or neuro-optic pathways among these former microelectronics workers. Exposure to ophthalmotoxic chemicals is proposed as the most probable risk factor.

  3. Effect of Bevacizumab vs Aflibercept on Visual Acuity Among Patients With Macular Edema Due to Central Retinal Vein Occlusion: The SCORE2 Randomized Clinical Trial.

    Science.gov (United States)

    Scott, Ingrid U; VanVeldhuisen, Paul C; Ip, Michael S; Blodi, Barbara A; Oden, Neal L; Awh, Carl C; Kunimoto, Derek Y; Marcus, Dennis M; Wroblewski, John J; King, Jacqueline

    2017-05-23

    Studies have established the efficacy and safety of aflibercept for the treatment of macular edema due to central retinal vein occlusion. Bevacizumab is used off-label to treat this condition despite the absence of supporting data. To investigate whether bevacizumab is noninferior to aflibercept for the treatment of macular edema secondary to central retinal or hemiretinal vein occlusion. The SCORE2 randomized noninferiority clinical trial was conducted at 66 private practice or academic centers in the United States, and included 362 patients with macular edema due to central retinal or hemiretinal vein occlusion who were randomized 1:1 to receive aflibercept or bevacizumab. The first participant was randomized on September 17, 2014, and the last month 6 visit occurred on May 6, 2016. Analyses included data available as of December 30, 2016. Eyes were randomized to receive intravitreal injection of bevacizumab (1.25 mg; n = 182) or aflibercept (2.0 mg; n = 180) every 4 weeks through month 6. The primary outcome was mean change in visual acuity (VA) letter score (VALS) from the randomization visit to the 6-month follow-up visit, based on the best-corrected electronic Early Treatment Diabetic Retinopathy Study VALS (scores range from 0-100; higher scores indicate better VA). The noninferiority margin was 5 letters, and statistical testing for noninferiority was based on a 1-sided 97.5% confidence interval. Among 362 randomized participants (mean [SD] age, 69 [12] years; 157 [43.4%] women; mean [SD] VALS at baseline, 50.3 [15.2] [approximate Snellen VA 20/100]), 348 (96.1%) completed the month 6 follow-up visit. At month 6, the mean VALS was 69.3 (a mean increase from baseline of 18.6) in the bevacizumab group and 69.3 (a mean increase from baseline of 18.9) in the aflibercept group (model-based estimate of between-group difference, -0.14; 97.5% CI, -3.07 to ∞; P = .001 for noninferiority), meeting criteria for noninferiority. Ocular adverse events in

  4. Validation of a Manually Oscillating Chair for In-The-Field Assessment of Dynamic Visual Acuity on Crewmembers Within Hours of Returning From Long-Duration Spaceflight

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    Kreutzberg, G. A.; Rosenberg, M. J. F.; Peters, B. T.; Reschke,M. F.

    2017-01-01

    Long-duration spaceflight results in sensorimotor adaptations, which cause functional deficits during gravitational transitions, such as landing on a planetary surface after long-duration microgravity exposure. Both the vestibular system and the central nervous system are affected by gravitational transitions. These systems are responsible for coordinating head and eye movements via the vestibulo-ocular reflex (VOR) and go through an adaptation period upon exposure to microgravity. Consequently, they must also re-adapt to Earth's gravitational environment upon landing. This re-adaptation causes decrements in gaze control and dynamic visual acuity, with crewmembers reporting oscillopsia and blurred vision caused by retinal slip, or the inability to keep an image focused on their retina. This is thought to drive motion sickness symptoms experienced by most crewmembers following landing. Retinal slip can be estimated by dynamic visual acuity (DVA); visual acuity while in motion. Previously, DVA has been assessed in the laboratory where subjects walked at 6.4 km/hr on a motorized treadmill. Using this method, Peters et al. (2011) found that DVA is worsened in astronauts by an average of 0.75 eye-chart lines one day after landing. However, it is believed that re-adaptation occurs quickly and that DVA might be worse immediately upon re-exposure to a gravitational environment. Since many crewmembers are unable to walk safely upon landing, it was necessary to develop a method for replicating the vertical head movements associated with walking. In addition, the use of a chair to imitate the head displacement caused by walking isolates eye-head interactions without allowing for trunk and lower-body compensation, as seen with treadmill walking (Mulavara & Bloomberg 2003). Therefore, a modality for assessing DVA in the field within a few hours of landing was developed. In this study, we validated the ability of a manually operated oscillating chair to reproduce the oscillatory

  5. [Comparison of the threshold interpolation and whole-line method on logMAR chart and Snellen chart for visual acuity testing].

    Science.gov (United States)

    Veselý, P; Ventruba, J

    2009-10-01

    The main goal of our study was to prove the statistical significant difference between the threshold interpolation logMAR method on ETDRS chart and the whole-line method on Snellen chart with Sloan letters. We had 108 measurements with the threshold interpolation method and the whole-line method on ETDRS chart and the whole-line method on Snellen chart. The average value measured with the threshold method in ETDRS was 1,132 (min. 0,660, max. 1,580), with the whole-line method on ETDRS it was 1,134 (min. 0,630, max. 1,580) and with the whole-line method on Snellen chart it was 1,183 (min. 0,630, max. 1,600). We have proved statistical significant difference between the threshold interpolation method made on ETDRS chart and the whole-line method made on Snellen chart (p Snellen chart were overvalued. The exact and reliable measuring of visual acuity is an important component of further examinations (e.g. contrast sensitivity, perimetry, tonometry), which enable us to make a correct diagnosis of pathological changes on human eye structures.

  6. Risk factors for decreased visual acuity in preschool children: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies.

    Science.gov (United States)

    Tarczy-Hornoch, Kristina; Varma, Rohit; Cotter, Susan A; McKean-Cowdin, Roberta; Lin, Jesse H; Borchert, Mark S; Torres, Mina; Wen, Ge; Azen, Stanley P; Tielsch, James M; Friedman, David S; Repka, Michael X; Katz, Joanne; Ibironke, Josephine; Giordano, Lydia

    2011-11-01

    To investigate risk factors associated with unilateral or bilateral decreased visual acuity (VA) in preschool children. Population-based, cross-sectional prevalence study. Population-based samples of 6504 children ages 30 to 72 months from California and Maryland. Participants were preschool African-American, Hispanic, and non-Hispanic white children from Los Angeles, California, and Baltimore, Maryland. Data were obtained by a parental interview and a detailed ocular examination. Logistic regression models were used to evaluate the independent associations between demographic, behavioral, and clinical risk factors with unilateral and bilateral decreased VA. Odds ratios (ORs) for various risk factors associated with interocular difference (IOD) in VA of ≥2 lines with ≤20/32 in the worse eye, or bilateral decreased VA preschool children should be considered in light of these risk associations. The authors have no proprietary or commercial interest in any of the materials discussed in this article. Copyright © 2011 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  7. Onset and duration of visual acuity improvement after dexamethasone intravitreal implant in eyes with macular edema due to retinal vein occlusion.

    Science.gov (United States)

    Kuppermann, Baruch D; Haller, Julia A; Bandello, Francesco; Loewenstein, Anat; Jiao, Jenny; Li, Xiao-Yan; Whitcup, Scott M

    2014-09-01

    To evaluate the onset and duration of improvement in best-corrected visual acuity (BCVA) in eyes treated with dexamethasone intravitreal implant 0.7 mg (DEX implant) for macular edema after branch or central retinal vein occlusion. Post hoc analysis of data from 2 previously reported multicenter, 6-month, randomized sham-controlled clinical trials. Patients received a single DEX implant (n = 427) or sham procedure (n = 426) in the study eye. The primary endpoint was the percentage of eyes with ≥ 15-letter improvement in BCVA from baseline at postimplant Day 7. The baseline mean BCVA was 20/80. At Day 7, 10.3% of DEX implant-treated eyes versus 4.0% of sham-treated eyes (P retinal vein occlusion, 5.1; and central retinal vein occlusion, 5.8) with DEX implant and 1.6 letters (branch retinal vein occlusion, 2.3; and central retinal vein occlusion, 0.1) with sham (P < 0.001). The mean time from initial observation of ≥ 15-letter BCVA gain to the last observation of ≥ 15-letter BCVA gain was 70 days. Dexamethasone intravitreal implant treatment led to improvement in BCVA compared with sham procedure as early as postimplant Day 7. The duration of ≥ 3-line improvement was typically 2 to 3 months.

  8. Monocular 3D display system for presenting correct depth

    Science.gov (United States)

    Sakamoto, Kunio; Hosomi, Takashi

    2009-10-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth.

  9. Reactivation of thalamocortical plasticity by dark exposure during recovery from chronic monocular deprivation

    Science.gov (United States)

    Montey, Karen L.; Quinlan, Elizabeth M.

    2015-01-01

    Chronic monocular deprivation induces severe amblyopia that is resistant to spontaneous reversal in adulthood. However, dark exposure initiated in adulthood reactivates synaptic plasticity in the visual cortex and promotes recovery from chronic monocular deprivation. Here we show that chronic monocular deprivation significantly decreases the strength of feedforward excitation and significantly decreases the density of dendritic spines throughout the deprived binocular visual cortex. Dark exposure followed by reverse deprivation significantly enhances the strength of thalamocortical synaptic transmission and the density of dendritic spines on principle neurons throughout the depth of the visual cortex. Thus dark exposure reactivates widespread synaptic plasticity in the adult visual cortex, including at thalamocortical synapses, during the recovery from chronic monocular deprivation. PMID:21587234

  10. PSD-95在正常发育和单眼剥夺大鼠视皮层的表达%Expression of PSD-95 in visual cortex of normal and monocular deprived rats

    Institute of Scientific and Technical Information of China (English)

    安喜艳; 赵堪兴

    2011-01-01

    目的 研究突触后致密物(post-synaptic density,PSD)-95在正常发育以及单眼视觉剥夺性大鼠视皮层中的蛋白动态表达情况,以期在突触水平为视觉发育可塑性提供分子基础.方法 健康生后14 d Wistar大鼠35只,随机分成正常组及单眼剥夺组,单眼剥夺组在生后14 d行单眼缝合术制备单眼剥夺模型.动物在同等环境下喂养,分别于生后14 d、21 d、28 d、45 d麻醉、灌注、固定、开颅、冠状切取后部脑组织(单眼剥夺组取剥夺眼对侧脑组织),进行常规HE和免疫组织化学方法染色.结果 HE染色中正常发育大鼠视皮层的神经元分布呈层状,且各层神经元排列整齐;单眼剥夺组大鼠视皮层未见明显异常.正常发育组PSD-95蛋白的表达随年龄呈发育性变化,生后21 d有明显升高(12.47±2.06),28 d(10.54±1.72)、45 d(11.65±1.55)持续在较高水平.PSD-95表达产物在单眼剥夺组较正常组明显减少.生后21 d(4.94±0.57)、28 d(5.20±0.47)、45 d(4.87±0.72)与正常组相比均下降(均为P<0.05).结论 PSD-95可能参与视觉发育敏感期视皮层神经元可塑性的调节.%Objective To study the dynamic expression of post-synaptic density (PSD)-95 in the visual cortex of normal and monocular deprived rats and provide the molecular mechanism of the visual plasticity at the level of synapse. Methods Thirty-five healthy Wistar rats with 14 days old were randomly divided into normal group (N) and monocular deprivation group (MD). The eyelids of MD groups were sutured at postnatal 14 days to obtain animal model. Rats were housed in alike environment, at postnatal 14 days,21 days,28 days,45 days the posterior brain coronally (get the brain opposite to deprived eye in the rats of MD) were cut after anesthesia, perfusion, fixation and opening cranium,the routine HE staining and immunohistochemistry staining were carried out. Results HE staining results showed the neurons of visual cortex in normal rats

  11. 基于单目视觉的移动机器人伺服镇定控制%Monocular camera-based mobile robot visual servo regulation control

    Institute of Scientific and Technical Information of China (English)

    刘阳; 王忠立; 蔡伯根; 闻映红

    2016-01-01

    To solve the monocular camera‐based mobile robot regulation problem ,the kinematic model in camera coordinate was proposed under the condition of unknown range information ,unknown translation parameter between robot and camera frames ,camera with certain dip angle .A robust and adaptive controller was proposed based on the assumptions above .The controller guaranteed exponen‐tial convergence of the system .The performance of the controller was validated by simulation and ex‐periment result ,showing that the controller could guarantees the robot rapidly and smoothly regulate to desired pose .T he controller is also robust to unknow n parameter .%针对轮式移动机器人的单目视觉伺服镇定问题,在深度信息、机器人坐标系与摄像机坐标系间平移参量未知、摄像头光轴具有固定倾角的情况下,建立了移动机器人在摄像机坐标系下的运动模型。针对该模型提出了一种基于平面单应矩阵分解的鲁棒自适应控制方法,保证了误差的全局指数收敛。仿真和实验结果表明:所设计的控制器可以保证移动机器人指数收敛到期望的位姿,同时所设计的鲁棒自适应控制器对参数不确定性具有一定的鲁棒性。

  12. Perceived Visual Distortions in Juvenile Amblyopes During/Following Routine Amblyopia Treatment.

    Science.gov (United States)

    Piano, Marianne E F; Bex, Peter J; Simmers, Anita J

    2016-08-01

    To establish the point prevalence of perceived visual distortions (PVDs) in amblyopic children; the association between severity of PVDs and clinical parameters of amblyopia; and the relationship between PVDs and amblyopia treatment outcomes. Perceived visual distortions were measured using a 16-point dichoptic alignment paradigm in 148 visually normal children (aged, 9.18 ± 2.51 years), and 82 amblyopic children (aged, 6.33 ± 1.48 years) receiving or following amblyopia treatment. Global distortion (GD; vector sum of mean-centered individual alignment error between physical and perceived target location) and Global uncertainty (GU; SD of GD over two experiment runs) were compared to age-matched control data, and correlated against clinical parameters of amblyopia (type, monocular visual acuity, pretreatment interocular acuity difference, refractive error, age at diagnosis, motor fusion, stereopsis, near angle of deviation) and amblyopia treatment outcomes (refractive adaption duration, treatment duration, occlusion dosage, posttreatment interocular acuity difference, number of lines improvement). Point prevalence of PVDs in amblyopes was 56.1%. Strabismic amblyopes experienced more severe distortions than anisometropic or microtropic amblyopes (GD Kruskal Wallis H = 16.89, P amblyopia treatment outcomes, or the amblyopic visual acuity deficit. Perceived visual distortions persisted in more than one-half of treated amblyopic cases whose treatment was deemed successful. Perceived visual distortions are common symptoms of amblyopia and are correlated with binocular (stereoacuity, angle of deviation), but not monocular (visual acuity) clinical outcomes. This adds to evidence demonstrating the role of decorrelated binocular single vision in many aspects of amblyopia, and emphasizes the importance of restoring and improving binocular single vision in amblyopic individuals.

  13. Uncorrected and Corrected Distance Visual Acuity, Predictability, Efficacy, and Safety after Femtosecond Laser in Situ Keratomileusis (FS-LASIK) and Refractive Lenticule extraction (ReLEx) for Moderate and High Myopia

    DEFF Research Database (Denmark)

    Vestergaard, Anders; Justesen, Birgitte Larsen; Melsen, Charlotte

    of Ophthalmology, Odense University Hospital, Denmark. Purpose: ReLEx is a relative new corneal refractive procedure, where a stromal lenticule is cut by a femtosecond laser and manually extracted. The purpose of this study was to compare uncorrected and corrected distance visual acuity (UDVA and CDVA), refractive......Title: Uncorrected and Corrected Distance Visual Acuity, Predictability, Efficacy, and Safety after Femtosecond Laser in Situ Keratomileusis (FS-LASIK) and Refractive Lenticule extraction (ReLEx) for Moderate and High Myopia. Vestergaard A., Justesen B., Melsen C., Lyhne N., Department...... and ReLEx treatments were made with a VisuMax® femto-second laser (Carl Zeiss-Meditec, Jena, Germany). In FS-LASIK, the photoablation was performed with a MEL-80 flying spot excimer laser (Carl Zeiss-Meditec, Jena, Germany). In ReLEx, lenticule diameter was 6.50 mm, whereas the FS-LASIK ablation zone...

  14. EARLY CRT MONITORING USING TIME-DOMAIN OPTICAL COHERENCE TOMOGRAPHY DOES NOT ADD TO VISUAL ACUITY FOR PREDICTING VISUAL LOSS IN PATIENTS WITH CENTRAL RETINAL VEIN OCCLUSION TREATED WITH INTRAVITREAL RANIBIZUMAB: A Secondary Analysis of Trial Data.

    Science.gov (United States)

    Bell, Katy J L; Hayen, Andrew; Glasziou, Paul; Mitchell, Andrew S; Farris, Maria; Wright, Jonathan; Duerr, Hans-Peter; Mitchell, Paul; Irwig, Les

    2017-03-01

    Our primary purpose was to assess the clinical (predictive) validity of central retinal thickness (CRT) and best corrected visual acuity (BCVA) at 1 week and 1 month after starting treatment with ranibizumab for central retinal vein occlusion. The authors also assessed detectability of response to treatment. The authors used data from 325 participants in the CRUISE study, which included measurement of time-domain CRT and BCVA at baseline, 1 week, 1 month, and 6 months postrandomization. Analysis of covariance models were fitted to assess clinical validity, and distributions of change were constructed to assess detectability of response. There was no evidence that 1-week CRT, and very strong evidence that 1-week BCVA were associated with baseline-adjusted BCVA at 6 months (P = 0.17 and P central retinal vein occlusion patients seemed more informative than time-domain optical coherence tomography monitoring.

  15. The UK Neovascular AMD Database Report 3: inter-centre variation in visual acuity outcomes and establishing real-world measures of care.

    Science.gov (United States)

    Liew, G; Lee, A Y; Zarranz-Ventura, J; Stratton, I; Bunce, C; Chakravarthy, U; Lee, C S; Keane, P A; Sim, D A; Akerele, T; McKibbin, M; Downey, L; Natha, S; Bailey, C; Khan, R; Antcliff, R; Armstrong, S; Varma, A; Kumar, V; Tsaloumas, M; Mandal, K; Egan, C; Johnston, R L; Tufail, A

    2016-11-01

    PurposeInternational variations in visual acuity (VA) outcomes of eyes treated for neovascular age-related macular degeneration (nAMD) are well-documented, but intra-country inter-centre regional variations are not known. These data are important for national quality outcome indicators. We aimed to determine intra-country and inter-centre regional variations in outcomes for treatment of nAMD.Patients and methodsProspective multicentre national database study of 13 UK centres that treated patients according to a set protocol (three loading doses, followed by Pro-Re-Nata retreatment). A total of 5811 treatment naive eyes of 5205 patients received a total of 36 206 ranibizumab injections over 12 months.ResultsMean starting VA between centres varied from 48.9 to 59.9 ETDRS letters. Mean inter-centre VA change from baseline to 12 months varied from +6.9 letters to -0.6 letters (mean of +2.5 letters). The proportion of eyes achieving VA of 70 letters or more varied between 21.9 and 48.7% at 12 months. Median number of injections (visits) at each centre varied from 5 to 8 (9 to 12), with an overall median of 6 (11). Age, starting VA, number of injections, and visits, but not gender were significantly associated with variation in these VA outcomes (Peven after adjusting for these factors.ConclusionThere are modest differences in VA outcomes between centres in the UK. These differences are influenced, but not completely explained, by factors such as patient age, starting VA, number of injections, and visits. These data provide an indication of the VA outcomes that are achievable in real-world settings.

  16. Second-year visual acuity outcomes of nAMD patients treated with aflibercept: data analysis from the UK Aflibercept Users Group.

    Science.gov (United States)

    Almuhtaseb, H; Johnston, R L; Talks, J S; Lotery, A J

    2017-06-16

    PurposeTo audit the visual acuity (VA) outcomes achieved at the end of year two in 17 UK centres, which followed the year 1 VIEW protocol in year 1, but a variable approach in year 2 for aflibercept for neovascular macular degeneration (nAMD).Patients and methodsRetrospective data analysis, from an electronic medical record, of a consecutive series of treatment-naive nAMD patients who received aflibercept for 2 consecutive years, having followed the VIEW protocol in year one, defined as eyes having received 7 or 8 injections from baseline.ResultsThe mean number of intravitreal injections (IVI)s during year 2 was 3.7 in 1180 eyes (1083 patients). The mean baseline VA of the whole cohort was 56.3 ETDRS letters, improving to 61.3 at 1 year (+5) and 59.1 (+2.8) at the end of year 2. The mean VA letter score at the end of year 2, stratified by number of IVIs into three groups was as follows: group A, 57.3 (gain of +1.7) (44% of eyes (/=6 IVIs)). Even though there were VA gains in the three groups over the 2-years, there was a drop in VA in year one to two. Eyes that received >/=6 IVIs (group C) had a smaller reduction of VA during year 2 than those which received year 1 results in higher VA gains in year 2 of treatment.Eye advance online publication, 16 June 2017; doi:10.1038/eye.2017.108.

  17. Five-year visual acuity outcomes and injection patterns in patients with pro-re-nata treatments for AMD, DME, RVO and myopic CNV.

    Science.gov (United States)

    Wecker, Thomas; Ehlken, Christoph; Bühler, Anima; Lange, Clemens; Agostini, Hansjürgen; Böhringer, Daniel; Stahl, Andreas

    2017-03-01

    Anti vascular endothelial growth factor (VEGF) therapy is an established treatment for various retinal diseases. Long-term data on injection frequencies and visual acuity (VA), however, are still rare. Five-year analysis of real-life VA developments and injection patterns from 2072 patients (2577 eyes; 33 187 injections) with chronically active disease undergoing pro-re-nata treatment for age-related macular degeneration (AMD), diabetic macular oedema (DME), retinal vein occlusion (RVO) and myopic choroidal neovascularisation (CNV). Maximum mean VA gain in year 1 was+5.2 letters in AMD, +6.2 in DME, +10 in RVO and+7.2 in myopic CNV. Over 5 years, however, VA in patients with AMD declined. By year 5, 34% of patients with AMD had experienced VA loss of >15 letters, 56% had remained stable and 10% had gained >15 letters. Long-term VA developments in DME and RVO were more favourable with 81% of DME and 79% of patients with RVO gaining or maintaining vision at 5 years. In AMD, median injection frequency was six in year 1 and between four and five in consecutive years. In DME and RVO, median injection frequency was six in year 1 but lower compared with AMD in consecutive years. Injection frequency in DME was weakly associated with patient age (rs=0.1; p=0.03). In AMD, the initial VA gain was not maintained long term despite higher injection numbers compared with DME, RVO and myopic CNV. The presented real-world data provide a peer-group-based estimate of VA developments and injection frequencies for counselling patients undergoing long-term anti-VEGF therapy. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  18. Importance of Central Retinal Sensitivity for Prediction of Visual Acuity after Intravitreal Bevacizumb in Eyes with Macular Edema Associated with Branch Retinal Vein Occlusion.

    Science.gov (United States)

    Sugimoto, Masahiko; Ichio, Atsushi; Kondo, Mineo

    2016-01-01

    To determine whether the baseline retinal sensitivity can predict the best-corrected visual acuity (BCVA) at 1 month after intravitreal bevacizumab (IVB) in eyes with macular edema (ME) associated with a branch retinal vein occlusion (BRVO). We evaluated 16 eyes of 16 patients who had ME associated with a BRVO. The mean ± standard deviation age was 69.1 ± 8.9 years, and all had a single IVB injection. The BCVA, central macular thickness (CMT), integrity of the ellipsoid zone (EZ) of the photoreceptors, and retinal sensitivity were determined before (baseline) and at 1 day, 1 week, and 1 month following the IVB. The average threshold retinal sensitivity (AT) within the central 10° was determined by Macular Integrity Assessment. The correlations between the BCVA at 1 month and the CMT, integrity of the EZ, and AT at each visit were determined. One month after IVB, the BCVA improved significantly from 0.56 ± 0.27 logMAR units to 0.32 ± 0.28 logMAR units, and the CMT from 611.4 ± 209.3 μm to 258.7 ± 64.0 μm (P retinal sensitivity (r = 0.76) were moderately correlated with the BCVA at 1 month. These results indicate that both the integrity of the EZ and the AT at 1 day after the IVB can predict the BCVA after treatment for ME associated with BRVO. There is a possibility that these parameters will predict the effectiveness of IVB for each case.

  19. Monocular occlusions determine the perceived shape and depth of occluding surfaces.

    Science.gov (United States)

    Tsirlin, Inna; Wilcox, Laurie M; Allison, Robert S

    2010-06-01

    Recent experiments have established that monocular areas arising due to occlusion of one object by another contribute to stereoscopic depth perception. It has been suggested that the primary role of monocular occlusions is to define depth discontinuities and object boundaries in depth. Here we use a carefully designed stimulus to demonstrate empirically that monocular occlusions play an important role in localizing depth edges and defining the shape of the occluding surfaces in depth. We show that the depth perceived via occlusion in our stimuli is not due to the presence of binocular disparity at the boundary and discuss the quantitative nature of depth perception in our stimuli. Our data suggest that the visual system can use monocular information to estimate not only the sign of the depth of the occluding surface but also its magnitude. We also provide preliminary evidence that perceived depth of illusory occluders derived from monocular information can be biased by binocular features.

  20. Short-Term Monocular Deprivation Enhances Physiological Pupillary Oscillations.

    Science.gov (United States)

    Binda, Paola; Lunghi, Claudia

    2017-01-01

    Short-term monocular deprivation alters visual perception in adult humans, increasing the dominance of the deprived eye, for example, as measured with binocular rivalry. This form of plasticity may depend upon the inhibition/excitation balance in the visual cortex. Recent work suggests that cortical excitability is reliably tracked by dilations and constrictions of the pupils of the eyes. Here, we ask whether monocular deprivation produces a systematic change of pupil behavior, as measured at rest, that is independent of the change of visual perception. During periods of minimal sensory stimulation (in the dark) and task requirements (minimizing body and gaze movements), slow pupil oscillations, "hippus," spontaneously appear. We find that hippus amplitude increases after monocular deprivation, with larger hippus changes in participants showing larger ocular dominance changes (measured by binocular rivalry). This tight correlation suggests that a single latent variable explains both the change of ocular dominance and hippus. We speculate that the neurotransmitter norepinephrine may be implicated in this phenomenon, given its important role in both plasticity and pupil control. On the practical side, our results indicate that measuring the pupil hippus (a simple and short procedure) provides a sensitive index of the change of ocular dominance induced by short-term monocular deprivation, hence a proxy for plasticity.

  1. Short-Term Monocular Deprivation Enhances Physiological Pupillary Oscillations

    Directory of Open Access Journals (Sweden)

    Paola Binda

    2017-01-01

    Full Text Available Short-term monocular deprivation alters visual perception in adult humans, increasing the dominance of the deprived eye, for example, as measured with binocular rivalry. This form of plasticity may depend upon the inhibition/excitation balance in the visual cortex. Recent work suggests that cortical excitability is reliably tracked by dilations and constrictions of the pupils of the eyes. Here, we ask whether monocular deprivation produces a systematic change of pupil behavior, as measured at rest, that is independent of the change of visual perception. During periods of minimal sensory stimulation (in the dark and task requirements (minimizing body and gaze movements, slow pupil oscillations, “hippus,” spontaneously appear. We find that hippus amplitude increases after monocular deprivation, with larger hippus changes in participants showing larger ocular dominance changes (measured by binocular rivalry. This tight correlation suggests that a single latent variable explains both the change of ocular dominance and hippus. We speculate that the neurotransmitter norepinephrine may be implicated in this phenomenon, given its important role in both plasticity and pupil control. On the practical side, our results indicate that measuring the pupil hippus (a simple and short procedure provides a sensitive index of the change of ocular dominance induced by short-term monocular deprivation, hence a proxy for plasticity.

  2. A comparative study on visual acuity and stereopsis outcomes between perceptual learning based on cloud services and conventional therapy for amblyopia%基于云服务技术的视知觉训练与传统综合训练对改善弱视患儿视力和立体视功能的疗效比较

    Institute of Scientific and Technical Information of China (English)

    汤玮玮; 王潇潇; 陶黎明

    2016-01-01

    Background Amblyopia is a developmental disorder of spatial vision that results in both monocular and binocular deficits.Conventional therapy for amblyopia which focuses on monocular training can improve visual acuity.However,how to improve the binocular function,especially stereopsis is rarely studied.Objective This study was to evaluate the outcome of perceptual learning based on cloud services of improving stcreopsis and visual acuity for amblyopia.Methods A randomized-controlled clinical study was performed.One hundred and seven amblyopic patients (178 eyes) with the age of 5-18 years old were recruited in The Second Affiliated Hospital of Anhui Medical University from July 2013 to March 2014.The patients were randomized into the perceptual learning group and the conventional therapy group.A perceptual learning based on cloud services with computer under the best corrected visual acuity was carried out in the perceptual learning group with 30-day duration as a course for 5-6 cycles,and training feedback data was obtained after each cycle for the regulation of following treatment.The dominant eye was covered during the training process.In the conventional therapy group,a training regimen of health eye covering that combined with eyesight training of amblyopic eye was performed.The stereopsis and visual acuity of the patients were estimated after training.Written informed consent was obtained from the parents or custodians of the children before entering the cohort.Results The total effective rate of visual acuity improvement is significantly higher in the perceptual learning group than that in the conventional therapy group after training (Z =6.368,P=0.012).The mean stereopsis value of the amblyopic eyes in the perceptual learning group and the conventional therapy group was (127±53)" and (174±67)" after training,which was significantly higher than (273 ±95)" and (311 ±103)" before training,respectively,and the increasing range of the mean stereopsis was

  3. The analysis of visual evoked potential in patients with monocular congenital ptosis%单眼先天性上睑下垂患儿图形视觉诱发电位分析

    Institute of Scientific and Technical Information of China (English)

    黄业贤; 周瑾; 胡兰香; 宋生芳; 项道满

    2014-01-01

    目的:探讨单眼先天性上睑下垂患儿图形视觉诱发电位(P-VEP)的特点,评估P-VEP对上睑下垂患儿双眼视觉功能检测的意义。方法对53例2~4岁单眼先天性上睑下垂患儿进行P-VEP检查,比较双眼P-VEP的P100潜伏期及振幅是否存在差异。结果上睑下垂眼VEP P100波潜伏期较正常组延长(P<0.01),振幅低于正常眼(P<0.01)。轻度上睑下垂眼P-VEP P100波振幅与中度及重度相比,差异有统计学意义(P<0.01),中度与重度相比差异无统计学意义,轻度上睑下垂眼P-VEP P100波潜伏期与中度相比差异无统计学意义,与重度比差异有统计学意义(P<0.01),中度与重度比较差异有统计学意义(P<0.05)。结论单眼先天性上睑下垂患者双眼P-VEP P100波振幅及潜伏期存在差异,根据患儿视觉发育程度进行手术时机选择的同时,应注意术后矫正弱视。%Objective To investigate the visual evoked potential (P-VEP) feature in patients with monocular congenital ptosis. To evaluate the significance of P-VEP in binocular vision.MethodsP-VEP response was recorded in 53 monocular congenital ptosis children who were 2-4 years old. Then compared the differences of latency period and waver of P100 wave.ResultsCompared with normal eye,the latency period of ptosis eyes was longer and the amplitude was lower(P<0.01).The differences of amplitude between mild ptosis eyes and midrange or severe ptosis eyes were significant (P<0.01) while they were not significantly between midrange and severe group.The differences of latency period between mild ptosis eyes and midrange eyes were not significant while they were significantlly between midrange and severe group(P<0.01,P<0.05).Conclusion Patients with monocular congenital ptosis edured differences response of P-VEP P100 in amplitude and latency period between two eyes.Attention should be focused on mblyopia after surgery.

  4. Effect of field of view and monocular viewing on angular size judgements in an outdoor scene

    Science.gov (United States)

    Denz, E. A.; Palmer, E. A.; Ellis, S. R.

    1980-01-01

    Observers typically overestimate the angular size of distant objects. Significantly, overestimations are greater in outdoor settings than in aircraft visual-scene simulators. The effect of field of view and monocular and binocular viewing conditions on angular size estimation in an outdoor field was examined. Subjects adjusted the size of a variable triangle to match the angular size of a standard triangle set at three greater distances. Goggles were used to vary the field of view from 11.5 deg to 90 deg for both monocular and binocular viewing. In addition, an unrestricted monocular and binocular viewing condition was used. It is concluded that neither restricted fields of view similar to those present in visual simulators nor the restriction of monocular viewing causes a significant loss in depth perception in outdoor settings. Thus, neither factor should significantly affect the depth realism of visual simulators.

  5. Acuity, crowding, reading and fixation stability.

    Science.gov (United States)

    Falkenberg, Helle K; Rubin, Gary S; Bex, Peter J

    2007-01-01

    People with age-related macular disease frequently experience reading difficulty that could be attributed to poor acuity, elevated crowding or unstable fixation associated with peripheral visual field dependence. We examine how the size, location, spacing and instability of retinal images affect the visibility of letters and words at different eccentricities. Fixation instability was simulated in normally sighted observers by randomly jittering single or crowded letters or words along a circular arc of fixed eccentricity. Visual performance was assessed at different levels of instability with forced choice measurements of acuity, crowding and reading speed in a rapid serial visual presentation paradigm. In the periphery: (1) acuity declined; (2) crowding increased for acuity- and eccentricity-corrected targets; and (3), the rate of reading fell with acuity-, crowding- and eccentricity-corrected targets. Acuity and crowding were unaffected by even high levels of image instability. However, reading speed decreased with image instability, even though the visibility of the component letters was unaffected. The results show that reading performance cannot be standardised across the visual field by correcting the size, spacing and eccentricity of letters or words. The results suggest that unstable fixation may contribute to reading difficulties in people with low vision and therefore that rehabilitation may benefit from fixation training.

  6. Bayesian depth estimation from monocular natural images.

    Science.gov (United States)

    Su, Che-Chun; Cormack, Lawrence K; Bovik, Alan C

    2017-05-01

    Estimating an accurate and naturalistic dense depth map from a single monocular photographic image is a difficult problem. Nevertheless, human observers have little difficulty understanding the depth structure implied by photographs. Two-dimensional (2D) images of the real-world environment contain significant statistical information regarding the three-dimensional (3D) structure of the world that the vision system likely exploits to compute perceived depth, monocularly as well as binocularly. Toward understanding how this might be accomplished, we propose a Bayesian model of monocular depth computation that recovers detailed 3D scene structures by extracting reliable, robust, depth-sensitive statistical features from single natural images. These features are derived using well-accepted univariate natural scene statistics (NSS) models and recent bivariate/correlation NSS models that describe the relationships between 2D photographic images and their associated depth maps. This is accomplished by building a dictionary of canonical local depth patterns from which NSS features are extracted as prior information. The dictionary is used to create a multivariate Gaussian mixture (MGM) likelihood model that associates local image features with depth patterns. A simple Bayesian predictor is then used to form spatial depth estimates. The depth results produced by the model, despite its simplicity, correlate well with ground-truth depths measured by a current-generation terrestrial light detection and ranging (LIDAR) scanner. Such a strong form of statistical depth information could be used by the visual system when creating overall estimated depth maps incorporating stereopsis, accommodation, and other conditions. Indeed, even in isolation, the Bayesian predictor delivers depth estimates that are competitive with state-of-the-art "computer vision" methods that utilize highly engineered image features and sophisticated machine learning algorithms.

  7. Confiabilidade da previsão da acuidade visual pós-operatória de catarata mediante medição da acuidade visual pré-operatória utilizando o retinômetro Heine Lambda 100 Reliability of predictable postoperative visual acuity of cataracts as measured by Heine Lambda 100 retinometer preoperatively

    Directory of Open Access Journals (Sweden)

    Guilherme Novoa Colombo-Barboza

    2010-06-01

    Full Text Available Objetivo: Utilizar o retinômetro de Heine Lambda 100 para avaliar a relação da acuidade visual obtida no pré-operatório de cirurgia de catarata com a acuidade visual obtida 3 meses no pós-operatório com correção óptica, bem como, sua correlação com a classificação morfológica dominante da catarata e com a intensidade da opacificação quando do tipo nuclear. Métodos: Trata-se de um estudo prospectivo realizado no Hospital Oftalmológico Visão Laser, em Santos, envolvendo 121 olhos de 70 pacientes avaliados de abril a julho 2009, submetidos à cirurgia de catarata sob a técnica de facoemulsificação com implante de lente intraocular. No período pré-operatório, foi realizado o retinômetro de Heine sob midríase e seu resultado foi comparado à melhor acuidade visual pós-operatória do terceiro mês e correlacionado com a classificação morfológica da catarata, quando do tipo nuclear, sendo denominado satisfatório aquele resultado que não variou mais do que duas linhas na tabela de Snellen. Resultados: Os resultados satisfatórios em nosso estudo foram de 86,78%, apresentando resultados de acuidade visual com retinômetro de Heine igual ao resultado da acuidade visual pós-operatória em 34,7%. A opacidade predominantemente nuclear N1+ tem um porcentual de acerto maior do que N2+ e N3+ (50%, 31,3% e 26,7%, respectivamente. Em relação ao total de olhos, observamos um teste extremamente significante (pPurpose: To assess the relationship between potential visual acuity obtained before cataract surgery using Heine Lambda 100 retinometer with best corrected visual acuity 3 months postoperatively, as well as its correlation with the morphological pattern of the dominant cataract and the intensity of nuclear opacification. Methods: Prospective study executed in the Ophthalmology Hospital Laser Vision in Santos of 121 eyes of 70 patients who underwent cataract surgery (phacoemulsification with intraocular lens implantation

  8. 西藏地区影响老年性白内障术后视力改善因素分析%Study of impact factors on visual acuity improvement for senile cataract surgery in Tibet

    Institute of Scientific and Technical Information of China (English)

    才瑜; 潘英姿; 聂红平; 杨松霖

    2010-01-01

    Objective To analyze impact factors for visual acuity improvement of senile cataract surgery in Tibet prospectively. Methods Of 278 cases were included. To study relations of visual acuity improvement between pre- and post-cataract surgery with patient age, nucleus classification, small incision cataract surgery (SICS) or Phacoemulsification (PHACO) and corneal edema. LogMAR chart was used in visual acuity analysis. Results 1. Univariate analysis: There was no significant difference between PHACO group and SICS group on visual acuity improvement (PHACO 0.92± 0.48, SICS 0.83± 0.46, P >0.05). Age group for 70- and 80- years-old had less improvement on visual acuity (P <0.05). Diffuse corneal edema had much more influence than central corneal edema on visual acuity improvement (0.52± 0.42, 0.70± 0.44, diffuse vs central, respectively). 2. Multivariate analysis: There were significant differences in age and location of corneal edema on visual acuity improvement (P <0.05). Conclusions There is no significant difference on visual acuity improvement between PHACO and SICS. Ophthalmologist can choose either PHACO or SICS for better rehabilitation of visual acuity, depending on area economics, his own experience and so on in Tibet. Visual acuity improvement in cataract surgery is significantly affected by the age of the patients. Since medication is deficient in Tebit, screening of cataract in Tibet is very important for detecting and treating cataract as early as possible. Diffuse corneal edema has much more influence than central edema on visual acuity improvement when corneal edema degrees are not different. It's important to avoid corneal endothelium damage in cataract surgery.%目的 分析影响西藏地区老年性白内障术后视力改善的因素.方法 对西藏地区接受白内障手术的老年性白内障278例,分析年龄、核分级、术式(超声乳化术和小切口白内障囊外摘除术)、人工晶状体度数、角膜水肿部位等对

  9. Evaluation of long-term visual performance following AcrySof ReSTOR lens implantation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yun-e; LI Jun-hua; ZHU Jun; WANG Dan-dan; WANG Qin-mei

    2009-01-01

    Background Multifocal lens has become popular in cataract surgery. Short-term outcome after AcrySof ReSTOR Lens implantation had been reported by many studies, but long-term visual performance and the effect of posterior capsular opacification (PCO) on visual performance need further investigation.Methods This retrospective study involved 54 eyes from 41 cataract patients implanted with ReSTOR lens, with a follow-up period of 12 to 31 months. Manifest refraction spherical equivalence (MRSE), monocular uncorrected and best-corrected distance visual acuity, uncorrected and distance-corrected near and intermediate visual acuity, contrast sensitivity were assessed. The effect of PCO on visual performance was evaluated by comparing visual parameters between pre and post-capsulotomy.Results Uncorrected distance visual acuity of eyes with MRSE within ±0.5 diopter (D) was better than those with MRSE greater than ±0.5 D (P <0.05). Uncorrected distance and near visual acuity (LogMAR) was 0.10 and 0.17 respectively.Best corrected distance visual acuity and best distance-corrected near visual acuity (LogMAR) was 0.00 and 0.16, a significant improvement was noted after correction (P=0.000, P=0.001, respectively). Contrast sensitivity logarithm was comparable with the normal value at difference spatial frequencies except at 12 cpd. In 5 eyes with mild PCO,post-capsulotomy visual parameters were better than pre-capsulotomy (P<0.05).Conclusion ReSTOR lens provides a good long-term distance and near vision, functional intermediate vision and contrast sensitivity. Mild PCO significantly affects visual performance and needs early intervention.

  10. Reversible monocular cataract simulating amaurosis fugax.

    Science.gov (United States)

    Paylor, R R; Selhorst, J B; Weinberg, R S

    1985-07-01

    In a patient having brittle, juvenile-onset diabetes, transient monocular visual loss occurred repeatedly whenever there were wide fluctuations in serum glucose. Amaurosis fugax was suspected. The visual loss differed, however, in that it persisted over a period of hours to several days. Direct observation eventually revealed that the relatively sudden change in vision of one eye was associated with opacification of the lens and was not accompanied by an afferent pupillary defect. Presumably, a hyperosmotic gradient had developed with the accumulation of glucose and sorbitol within the lens. Water was drawn inward, altering the composition of the lens fibers and thereby lowering the refractive index, forming a reversible cataract. Hypoglycemia is also hypothesized to have played a role in the formation of a higher osmotic gradient. The unilaterality of the cataract is attributed to variation in the permeability of asymmetric posterior subcapsular cataracts.

  11. Visual and refractive outcomes after implantation of a fully diffractive trifocal lens

    Directory of Open Access Journals (Sweden)

    Cochener B

    2012-09-01

    Full Text Available Béatrice Cochener,1 Jérome Vryghem,2 Pascal Rozot,3 Gilles Lesieur,4 Steven Heireman,2 Johan A Blanckaert,5 Emmanuel Van Acker,6 Sofie Ghekiere51Ophthalmology Department, University Hospital CHU, Brest, France; 2Brussels Eye Doctors, Brussels, Belgium; 3Ophthalmology Department, Clinique Monticelli, Marseille, 4Centre Ophtalmologique Iridis, Albi, France; 5Ophthalmology Department, Jan Yperman Ziekenhuis, Ieper, 6Ophthalmology Department, Clinique Saint Joseph, Lobbes, BelgiumBackground: The purpose of this study was to record the visual outcomes of patients treated by six surgeons after implantation of a trifocal lens.Methods: The setting for this study comprised six ophthalmology units and eye clinics in Belgium and France, with a coordinating center in France, and data management and statistical analysis in France and Belgium. Ninety-four eyes from 47 patients were implanted with a trifocal FineVision® intraocular lens by six surgeons. Monocular and binocular, uncorrected and best distance-corrected, and photopic and mesopic visual acuity was measured, as well as the defocus curve between +4 D and –4 D with best distance correction.Results: Near and far monocular visual acuities were similar to the data published after bifocal intraocular lens implantation. Intermediate vision was improved, and was demonstrated by scores of near visual acuity as well as far visual acuity with defocus –1.5 D-add lens. Far vision is maintained in mesopic conditions.Conclusion: The trifocal intraocular lens provides good far, intermediate, and near visual acuity.Keywords: trifocal intraocular lens, multifocal intraocular lens, cataract surgery, diffractive intraocular lens

  12. Cirurgia monocular para esotropias de grande ângulo: um novo paradigma Monocular surgery for large-angle esotropias: a new paradigm

    Directory of Open Access Journals (Sweden)

    Edmilson Gigante

    2009-02-01

    anesthesia and received no adjustable sutures. The methods used for refractometry, measurement of visual acuity and angle of deviation were those traditionally used in strabismology. Postoperatively, measurements in primary position (and side gaze were carried out, along with assessments of limitations to adduction or abduction of the operated eye. RESULTS: Four groups comprised the study according to four periods of time: one week, six months, two years and four to seven years. The results for the postoperative angle of deviation were compatible with those reported in the literature, and remained stable in the folllowup. The motility of the operated eye presented a slight limitation in adduction and no limitation in abduction, contradicting the findings presented in the strabologic literature. No statistically significant differences were detected in the comparison between adults and children, neither regarding amblyopes and non-amblyopes. CONCLUSION: Monocular recession-resection surgery seems to be a valid option in the treatment of large-angle esotropias, both for adults and children, as well as for amblyopes and non-amblyopes.

  13. Motor skills of children with unilateral visual impairment in the Infant Aphakia Treatment Study.

    Science.gov (United States)

    Celano, Marianne; Hartmann, E Eugenie; DuBois, Lindreth G; Drews-Botsch, Carolyn

    2016-02-01

    To assess motor functioning in children aged 4 years 6 months enrolled in the Infant Aphakia Treatment Study, and to determine contributions of visual acuity and stereopsis to measured motor skills. One hundred and four children (53% female) with unilateral aphakia randomized to intraocular lens or contact lens treatment were evaluated at 4 years 6 months (age range 4y 6mo-4y 11mo) for monocular recognition visual acuity, motor skills, and stereopsis by a traveling examiner masked to treatment condition. Motor skills were assessed with the Movement Assessment Battery for Children--Second Edition (MABC-2). Visual acuity was operationalized as log10 of the minimum angle of resolution (logMAR) value for treated eye, best logMAR value for either eye, and intraocular logMAR difference. Student's t-tests showed no significant differences in MABC-2 scores between the intraocular lens and contact lens groups. The mean total score was low (6.43; 18th centile) compared with the normative reference group. Motor functioning was not related to visual acuity in the treated eye or to intraocular logMAR difference, but was predicted in a regression model by the better visual acuity of either eye (usually the fellow eye), even after accounting for the influence of age at surgery, examiner, orthotropic ocular alignment, and stereopsis. Children with unilateral congenital cataract may have delayed motor functioning at 4 years 6 months, which may adversely affect their social and academic functioning. © 2015 Mac Keith Press.

  14. Monocular 3D display unit using soft actuator for parallax image shift

    Science.gov (United States)

    Sakamoto, Kunio; Kodama, Yuuki

    2010-11-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax images. But conventional image shift mechanism is heavy because of its linear actuator system. To improve this problem, we developed a light-weight 3D vision unit for presenting monocular stereoscopic images using a soft linear actuator made of a polypyrrole film.

  15. Light-weight monocular display unit for 3D display using polypyrrole film actuator

    Science.gov (United States)

    Sakamoto, Kunio; Ohmori, Koji

    2010-10-01

    The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax images. But conventional image shift mechanism is heavy because of its linear actuator system. To improve this problem, we developed a light-weight 3D vision unit for presenting monocular stereoscopic images using a polypyrrole linear actuator.

  16. Four-Year Incidence and Progression of Visual Impairment in Latinos: The Los Angeles Latino Eye Study (LALES)

    Science.gov (United States)

    Varma, Rohit; Chung, Jessica; Foong, Althena W.P.; Torres, Mina; Choudhury, Farzana; Azen, Stanley P.

    2010-01-01

    Purpose To determine the 4-year incidence of visual impairment (VI) and blindness and worsening of visual acuity in adult Latinos/Hispanics aged 40 years and older. Design Population-based, longitudinal study. Methods Participants underwent a detailed ophthalmologic examination including assessing both presenting binocular (PVA) and best-corrected distance visual acuity (BCVA) in both eyes using a standard ETDRS protocol. The main outcome measures are 4-year incidence of visual impairment and blindness based on PVA or BCVA in the better seeing eye and defined as 1) baseline visual acuity (PVA or BCVA)≥20/40 and a follow-up PVA or BCVA20/200 and a follow-up PVA≤20/200 respectively. Monocular worsening was defined as a decrease of ≥5, 10, and 15 letters in either eye. Results Four thousand six hundred and fifty eight participants were examined at baseline and the 4-year follow-up. The 4-year incidence of presenting binocular VI and blindness was 2.9% and 0.3%. The 4-year incidence of best corrected VI and blindness was 1.2% and 0.3%. The 4-year incidence of monocular worsening by ≥5, 10, and 15 letters was 24.8%, 8.5% and 3.1% respectively. The incidence of VI and blindness increased with age at baseline (Pvisual impairment and blindness should focus on the older Latino population. PMID:20399925

  17. [Landolt C and snellen e acuity: differences in strabismus amblyopia?].

    Science.gov (United States)

    Becker, R; Gräf, M

    2006-01-01

    Assessment of visual acuity depends on the optotypes used for measurement. The ability to recognize different optotypes differs even if their critical details appear under the same visual angle. Since optotypes are evaluated on individuals with good visual acuity and without eye disorders, differences in the lower visual acuity range cannot be excluded. In this study, visual acuity measured with the Snellen E was compared to the Landolt C acuity. 100 patients (age 8 - 90 years, median 60.5 years) with various eye disorders, among them 39 with amblyopia due to strabismus, and 13 healthy volunteers were tested. Charts with the Snellen E and the Landolt C (Precision Vision) which mimic the ETDRS charts were used to assess visual acuity. Three out of 5 optotypes per line had to be correctly identified, while wrong answers were monitored. In the group of patients, the eyes with the lower visual acuity, and the right eyes of the healthy subjects, were evaluated. Differences between Landolt C acuity (LR) and Snellen E acuity (SE) were small. The mean decimal values for LR and SE were 0.25 and 0.29 in the entire group and 0.14 and 0.16 for the eyes with strabismus amblyopia. The mean difference between LR and SE was 0.55 lines in the entire group and 0.55 lines for the eyes with strabismus amblyopia, with higher values of SE in both groups. The results of the other groups were similar with only small differences between LR and SE. Using the charts described, there was only a slight overestimation of visual acuity by the Snellen E compared to the Landolt C, even in strabismus amblyopia. Small differences in the lower visual acuity range have to be considered.

  18. Apparent motion of monocular stimuli in different depth planes with lateral head movements.

    Science.gov (United States)

    Shimono, K; Tam, W J; Ono, H

    2007-04-01

    A stationary monocular stimulus appears to move concomitantly with lateral head movements when it is embedded in a stereogram representing two front-facing rectangular areas, one above the other at two different distances. In Experiment 1, we found that the extent of perceived motion of the monocular stimulus covaried with the amplitude of head movement and the disparity between the two rectangular areas (composed of random dots). In Experiment 2, we found that the extent of perceived motion of the monocular stimulus was reduced compared to that in Experiment 1 when the rectangular areas were defined only by an outline rather than by random dots. These results are discussed using the hypothesis that a monocular stimulus takes on features of the binocular surface area in which it is embedded and is perceived as though it were treated as a binocular stimulus with regards to its visual direction and visual depth.

  19. Secular trends of reduced visual acuity from 1985 to 2010 and disease burden projection for 2020 and 2030 among primary and secondary school students in China.

    Science.gov (United States)

    Sun, Hong-Peng; Li, Ang; Xu, Yong; Pan, Chen-Wei

    2015-03-01

    Understanding the burden and trends of reduced visual acuity (VA), a proxy measure for myopia, is essential to guide future health care and clinical management in China. To describe the secular trends from 1985 to 2010, correlate the prevalence of reduced VA among children and adolescents with population density, and project the burden of reduced VA in China in 2020 and 2030. The National Survey on the Constitution and Health of Chinese Students conducted from 1985 to 2010, including 6 repeated surveys with a 3-stage clustering sampling strategy. Mainland China. Primary and secondary school students 7 to 18 years of age were randomly selected from 30 of 31 mainland provinces, excluding Tibet. Unaided distance VA was measured using a retroilluminated logMAR chart with tumbling-E optotypes. World Population Prospects data (the 2012 revision from the Population Division of the Department of Economic and Social Affairs of the United Nations) were used to project the number of people affected by reduced VA in 2020 and 2030. This analysis included 725 423, 142 655, 206 601, 219 663, 234 377, and 215 308 students in 1985, 1991, 1995, 2000, 2005, and 2010, respectively. The overall prevalence of reduced VA was 28.6% (95% CI, 28.4%-28.7%) in 1985, 38.6% (95% CI, 38.3%-38.8%) in 1991, 41.0% (95% CI, 40.8%-41.2%) in 1995, 38.5% (95% CI, 38.3%-38.7%) in 2000, 49.5% (95% CI, 49.3%-49.7%) in 2005, and 56.8% (95% CI, 56.6%-57.0%) in 2010. Girls were more susceptible than boys to having reduced VA (odds ratio, 1.38 [95% CI, 1.35-1.40]), and reduced VA was more prevalent in urban areas than in rural areas (odds ratio, 1.84 [95% CI, 1.81-1.87]). Reduced VA was not significantly associated with population density (P = .11). The projected numbers of cases with reduced VA are about 152.4 million (95% CI, 151.9-152.9 million) in 2020, increasing to 180.4 million (95% CI, 179.8-181.2 million) in 2030 among students who are 7 to 18 years of age in mainland China. There was

  20. De olhos bem abertos: investigando acuidade visual em alunos de uma escola municipal de Vitória De ojos bien abiertos: investigar la agudeza visual de los alumnos de una escuela municipal en la ciudad de Vitória With opened eyes: evaluating the visual acuity of children at an elementary school in Vitória

    Directory of Open Access Journals (Sweden)

    Mariana Rabello Laignier

    2010-03-01

    profesional de la salud es esencial en el desarrollo de proyectos destinados a la salud escolar.This research evaluates the visual acuity of children at Prezideu Amorim Elementary School in the city of Vitória Espírito Santo, based on applying the scale of Snellen; and children who had visual disorders were referred to specialist examination at the ophthalmology clinic of Antônio Cassiano Moraes University Hospital. This essay develops a study of quantitative approach and discussed visual acuity related to sex, age, grade, use of corrective lenses and medical diagnosis. The results showed that the girls present greater prevalence of low visual acuity, as well as the younger age ranks; the use of lenses prevails on those that presented reduction of the visual acuity; and the majority of the children sent to the doctor presented some degree of ametropy. It concluded that prevention in order to get an excellent visual health is a duty of the health professional and of the professor, that together, they can develop other projects in the field of school health.

  1. Loop Closure Detection Algorithm Based on Monocular Vision Using Visual Dictionary%基于视觉词典的单目视觉闭环检测算法

    Institute of Scientific and Technical Information of China (English)

    梁志伟; 陈燕燕; 朱松豪; 高翔; 徐国政

    2013-01-01

    Aiming at the problem of loop closure detection in monocular simultaneous localization and mapping for mobile robots,a detection algorithm based on visual dictionary (VD) is presented.Firstly,feature extraction is performed for each required image using SURF methods.Subsequently,a fuzzy K-means algorithm is employed to cluster these visual feature vectors into visual words based on VD which is constructed online.To precisely represent the similarities between each visual word and corresponding local visual features,Gaussian mixture model is proposed to learn the probability model of every visual word in bags of visual words.Consequently,every image can be denoted as a probabilistic vector of VD,and thus the similarities between any two images can be computed based on vector inner product.To guarantee the continuity of the closed-loop detection,a Bayesian filter method is applied to fuse historical closed-loop detection information and the obtained similarities to calculate the posterior probability distribution of closed-loop hypothesis.Furthermore,two memory management mechanisms,shallow memory and deep memory,are introduced to improve the process speed of the proposed algorithm.The experimental results demonstrate the validity of the proposed approach.%针对移动机器人单目视觉同步定位与地图构建中的闭环检测问题,文中设计一种基于视觉词典的闭环检测算法.算法对采集的每帧图像通过SURF进行特征提取,应用模糊K均值算法对检测的视觉特征向量进行分类,在线构建表征图像的视觉词典.为精确表征局部视觉特征与视觉单词间的相似关联,利用混合高斯模型建立视觉词典中的每一视觉单词的概率模型,实现图像基于视觉词典的概率向量表示,通过向量的内积来计算图像间的相似度.为保证闭环检测的成功率,应用贝叶斯滤波融合历史闭环检测与相似度信息来计算闭环假设的后验概率分布.另外,引入浅层

  2. Saccade amplitude disconjugacy induced by aniseikonia: role of monocular depth cues.

    Science.gov (United States)

    Pia Bucci, M; Kapoula, Z; Eggert, T

    1999-09-01

    The conjugacy of saccades is rapidly modified if the images are made unequal for the two eyes. Disconjugacy persists even in the absence of disparity which indicates learning. Binocular visual disparity is a major cue to depth and is believed to drive the disconjugacy of saccades to aniseikonic images. The goal of the present study was to test whether monocular depth cues can also influence the disconjugacy of saccades. Three experiments were performed in which subjects were exposed for 15-20 min to a 10% image size inequality. Three different images were used: a grid that contained a single monocular depth cue strongly indicating a frontoparallel plane; a random-dot pattern that contained a less prominent monocular depth cue (absence of texture gradient) which also indicates the frontoparallel plane; and a complex image with several overlapping geometric forms that contained a variety of monocular depth cues. Saccades became disconjugate in all three experiments. The disconjugacy was larger and more persistent for the experiment using the random-dot pattern that had the least prominent monocular depth cues. The complex image which had a large variety of monocular depth cues produced the most variable and less persistent disconjugacy. We conclude that the monocular depth cues modulate the disconjugacy of saccades stimulated by the disparity of aniseikonic images.

  3. A Data Mining Project to Identify Cardiovascular Related Factors That May Contribute to Changes in Visual Acuity Within the US Astronaut Corps

    Science.gov (United States)

    Westby, Christian M.; Stein, Sydney P.; Platts, Steven H.

    2011-01-01

    clearly differentiated the two mission types. Statistical analysis confirmed that pulse pressure was significantly higher before [45.6; (42.1 to 49.1)] and after [50.7; (46.9 to 54.6)] time on station compared with their most recent shuttle flight [31.6 (27.8 to 35.4), and 32.2 (28.3 to 36.0) respectively] even after correcting differences in age and cumulative number of mission hours. Without knowing the identity of which long duration crewmembers demonstrated visual changes, we were limited to examining whether certain crew regulate components of pulse pressure, systolic and diastolic blood pressure, differently due to microgravity exposure. To that end, we stratified crew into tertiles based on either their pre-flight measure of systolic or diastolic blood pressure. Those crew in the highest tertile for both systolic (lower tertile (n=8; 103-111), middle tertile (n=7; 113-121), and upper tertile (n=5; 125-136) and diastolic blood pressure (lower tertile (n=8; 58-64), middle tertile (n=7; 67-73), and upper tertile (n=5; 75-81) demonstrated less variability in pulse pressure between R+0 and L-10 (Figure 2). Interestingly, those crewmembers with the highest resting systolic blood pressure demonstrated either no change or in some instances an increase in total peripheral resistance, where those in the lower tertiles had lower values of total peripheral resistance compared to pre-flight levels. In this study, it was found that crewmembers in the highest tertile for both systolic and diastolic blood pressure demonstrated less variability in pulse pressure and that the decrease in variability was due in part to lower levels of compliance as indicated by similar or higher levels of total peripheral resistance after compared with before flight levels. Whether there is a relation between blood pressure regulation and total peripheral resistance in crew presenting with negative changes in visual acuity remains unknown.

  4. Investigation and analysis of visual acuity of students in one health school%某卫生学校学生视力状况调查分析

    Institute of Scientific and Technical Information of China (English)

    董兆

    2015-01-01

    Objective To investigate and analysis students' vision in one health school and the influence factors of low vision, which will provide a scientific basis for further improve students' visual acuity level.Methods: In a random sample of one health school four professional in grade 2010-2014, a total of 2238 students as investigation object, and using E type international standard logarithmic chart and related questionnaire, detection, investigation and statistical analysis.Results: The total poor vision rate of the respondents was 83.87%. give priority to with moderate, The rate in female respondents(85.54%) was higher than that of male(76.67%). The rate(87.29%) in senior students (grade 4 and 5) was higher than that of junior (grade 1~3) students(79.34%). The rate in nursing students(86.46%) was higher than that of other students(P<0.05). The students with normal vision pay more attention to maintain the correct reading distance, the using time of mobile phones everyday is shorter, more like sports, more like animal liver and vegetables. Objective: The main cause of the health school students vision loss is myopic, vision care is a dififcult task. Bad behaviors of using eyes, lack of exercise, poor dietary habits are all risk factors of poor vision.%目的 了解某卫生学校学生的视力状况以及视力低下的影响因素,为进一步改善学生视力水平提供科学依据.方法 以随机抽取的某卫生学校2010级至2014级四个专业共2238名学生为调查对象,采用E字型国际标准对数视力表和相关调查问卷,进行检测、调查和统计分析.结果 被调查者的视力低下率为83.87%,以中度为主,女生(85.54%)视力低下率高于男生(76.67%),高年级(四、五年级)学生视力低下率(87.29%)高于低年级(一、二、三年级)学生(79.34%),护理专业学生的视力低下率(86.46%)高于其他专业学生(P<0.05).视力正常的学生更注意保持正确的阅读距离、每天使用手机的时间较

  5. Reliability of visual acuity measurements taken with a notebook and a tablet computer in participants who were illiterate to Roman characters.

    Science.gov (United States)

    Ruamviboonsuk, Paisan; Sudsakorn, Napitchareeya; Somkijrungroj, Thanapong; Engkagul, Chayanee; Tiensuwan, Montip

    2012-03-01

    Electronic measurement of visual acuity (VA) has been proposed and adopted as a method of determining VA scores in clinical research. Characters (optotypes) are displayed on a monitor screen and the examinee selects a match and inputs his choice to another electronic device. Unfortunately, the optotypes, called Sloan letters, in the standard protocol are 10 Roman characters. This limits their practicabilityfor measuring VA of patients who are illiterate to these characters. The authors introduced a method of displaying the Sloan letters one by one on a notebook and all 10 Sloan letters on a tablet computer screen. The former is for testing the patients whereas the latter is for them to input their responses by tapping on a letter that matches the one on the notebook screen. To assess test-retest reliability of VA scores determined with this method. Participants without ocular abnormality were recruited to have their right eyes measured with the same VA measurement method twice, one week apart. Those who were illiterate to Roman characters were enrolled for the aforementioned method for measuring their VA (Tablet group). A 15-inch display notebook computer and a 9-inch display tablet computer (iPad) communicated via a local wireless data network provided by a Wi-Fi router. Those who understood Roman characters were enrolled to have measurements with a 17-inch desktop computer and an infrared wireless keyboard (Keyboard group). Both methods used the same protocols and software for VA measurements. Reliability of VA scores obtained from each group was assessed by the confidence interval (CI) of the difference of the scores from the test and retest. The t test was used to analyze differences in mean VA scores between the test and retest in each group with p < 0.05 determined as statistically significant. There were 49 and 50 participants in the Tablet and Keyboard group respectively. The 95% CI of the difference between the scores from the test and retest in each group

  6. Monocular nasal hemianopia from atypical sphenoid wing meningioma.

    Science.gov (United States)

    Stacy, Rebecca C; Jakobiec, Frederick A; Lessell, Simmons; Cestari, Dean M

    2010-06-01

    Neurogenic monocular nasal field defects respecting the vertical midline are quite uncommon. We report a case of a unilateral nasal hemianopia that was caused by compression of the left optic nerve by a sphenoid wing meningioma. Histological examination revealed that the pathology of the meningioma was consistent with that of an atypical meningioma, which carries a guarded prognosis with increased chance of recurrence. The tumor was debulked surgically, and the patient's visual field defect improved.

  7. Dynamic object recognition and tracking of mobile robot by monocular vision

    Science.gov (United States)

    Liu, Lei; Wang, Yongji

    2007-11-01

    Monocular Vision is widely used in mobile robot's motion control for its simple structure and easy using. An integrated description to distinguish and tracking the specified color targets dynamically and precisely by the Monocular Vision based on the imaging principle is the major topic of the paper. The mainline is accordance with the mechanisms of visual processing strictly, including the pretreatment and recognition processes. Specially, the color models are utilized to decrease the influence of the illumination in the paper. Some applied algorithms based on the practical application are used for image segmentation and clustering. After recognizing the target, however the monocular camera can't get depth information directly, 3D Reconstruction Principle is used to calculate the distance and direction from robot to target. To emend monocular camera reading, the laser is used after vision measuring. At last, a vision servo system is designed to realize the robot's dynamic tracking to the moving target.

  8. A variação da acuidade visual durante esforços físicos em atletas com baixa visão, participantes de seleção brasileira de atletismo The visual acuity variability during physical efforts in low vision athletes from the athletics Brazilian team

    Directory of Open Access Journals (Sweden)

    Ciro Winckler de Oliveira Filho

    2007-08-01

    Full Text Available INTRODUÇÃO E OBJETIVO: Esta pesquisa teve como objetivo avaliar o comportamento da acuidade visual em atletas com baixa visão, durante um protocolo de esforço contínuo. Pesquisas apontam que a acuidade visual apresenta variações de rendimento quando submetida a esforços físicos em sujeitos sem deficiência visual. MÉTODO: A população estudada foi composta por seis pessoas, praticantes de atletismo e integrantes da seleção brasileira em provas de pista. No primeiro dia aplicou-se o teste de esforço físico progressivo, realizado em esteira. No segundo dia realizou-se o teste de esforço contínuo, o qual foi dividido em três níveis, cada um com 15 minutos de duração e 30 minutos de intervalo entre eles. Como delimitador das intensidades aplicadas utilizaram-se os resultados obtidos no teste de físico progressivo (60% do VE pico, limiar de VE e 90% do VE pico. A aferição da acuidade visual aconteceu antes, durante e após cada nível de intensidade no protocolo de esforço contínuo. O teste t de Student foi utilizado para a análise estatística (p INTRODUCTION AND OBJECTIVE: This study had as an objective to evaluate the visual acuity behavior in athletes with low vision, during a continuous effort protocol. Researches point out that visual acuity presents performance varieties when submitted to physical efforts in subjects without visual impairment. METHOD: The studied population was composed by six peoples, who practiced athletics and were part of the Brazilian team in track events. The progressive physical effort test was applied on the first day in a treadmill. On the second day the continuous effort test was applied, which was divided in three levels, each one had a 15 and 30 minutes break between them. To determine the intensities, the results obtained in the progressive physical effort test (60% of VE peak, limiar VE and 90% VE peak were used. The visual acuity was measured before, during and after each level of

  9. Visual performance in cataract patients with low levels of postoperative astigmatism: full correction versus spherical equivalent correction

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    Lehmann RP

    2012-03-01

    Full Text Available Robert P Lehmann1, Diane M Houtman21Lehmann Eye Center, Nacogdoches, TX, 2Alcon Research Ltd, Fort Worth, TX, USAPurpose: To evaluate whether visual performance could be improved in pseudophakic subjects by correcting low levels of postoperative astigmatism.Methods: An exploratory, noninterventional study was conducted using subjects who had been implanted with an aspheric intraocular lens and had 0.5–0.75 diopter postoperative astigmatism. Monocular visual performance using full correction was compared with visual performance using spherical equivalent correction. Testing consisted of high- and low-contrast visual acuity, contrast sensitivity, and reading acuity and speed using the Radner Reading Charts.Results: Thirty-eight of 40 subjects completed testing. Visual acuities at three contrast levels (100%, 25%, and 9% were significantly better using full correction than when using spherical equivalent correction (all P < 0.001. For contrast sensitivity testing under photopic, mesopic, and mesopic with glare conditions, only one out of twelve outcomes demonstrated a significant improvement with full correction compared with spherical equivalent correction (at six cycles per degree under mesopic without glare conditions, P = 0.046. Mean reading speed was numerically faster with full correction across all print sizes, reaching statistical significance at logarithm of the reading acuity determination (logRAD 0.2, 0.7, and 1.1 (P , 0.05. Statistically significant differences also favored full correction in logRAD score (P = 0.0376, corrected maximum reading speed (P < 0.001, and logarithm of the minimum angle of resolution/logRAD ratio (P < 0.001.Conclusions: In this study of pseudophakic subjects with low levels of postoperative astigmatism, full correction yielded significantly better reading performance and high- and low-contrast visual acuity than spherical equivalent correction, suggesting that cataractous patients may benefit from surgical

  10. Diffusion tensor imaging correlates of visual impairment in multiple sclerosis and chronic optic neuritis.

    Science.gov (United States)

    Kolbe, Scott C; Marriott, Mark; Walt, Anneke van der; Fielding, Joanne; Klistorner, Alexander; Mitchell, Peter J; Butzkueven, Helmut; Kilpatrick, Trevor J; Egan, Gary F

    2012-02-21

    To compare white matter (WM) injuries associated with vision loss in multiple sclerosis (MS) and optic neuritis (ON). Twenty-three patients with clinically definite relapsing-remitting MS and chronic unilateral ON and 14 neurologically healthy volunteers were monocularly tested with Sloan 100%, 2.5%, and 1.25% contrast visual acuity charts. Primary visual pathway and whole-brain WM injury were assessed with optical coherence tomography (OCT) and diffusion tensor imaging (DTI). OCT and DTI correlates of high- and low-contrast visual impairment were identified using correlation analyses. The MS patients displayed significantly reduced retinal nerve fiber layer (RNFL) thickness and altered optic nerve and radiation DTI measures compared with the controls. In the patients, 2.5% and 1.25% contrast letter acuity in the unaffected eye correlated significantly and independently with optic nerve and optic radiation DTI measures. Visual acuity in affected eyes did not correlate with optic nerve or optic radiation DTI measures, but did correlate with DTI measures in prefrontal and temporal brain regions that were shown to connect structurally to visual cortices. In unaffected eyes, visual impairment was associated with WM injury in the visual pathway. In contrast, irrecoverable visual impairment after ON was associated with injury to frontal WM, which potentially impairs the capacity for remapping visual processing.

  11. Comparison of the INNOVA Visual Acuity System Stereotest with the Frisby-Davis 2 Stereotest for the Evaluation of Distance Stereoacuity.

    Science.gov (United States)

    Singman, Eric L; Matta, Noelle S; Silbert, David I; Tian, Jin

    2013-01-01

    Distance stereo acuity has been shown to be useful in monitoring conditions such as control of intermittent strabismus. The Frisby Davis distance (FD2) stereotest has been shown to be reliable and is felt to be the gold standard in England. The device however is not widely available in the United States or Canada and is not automated. This study compares the Innova distance stereoacuity test with the Frisby Davis distance (FD2) stereotest. Twenty-seven patients with normal acuity and a normal ophthalmology exam were evaluated. Prior to dilation all patients had an Innova distance stereoacuity test and FD2 test. Both the Innova distance stereoacuity test and the FD2 test were performed at ten feet. The results of the tests were compared using Bland-Altman plot analysis. The INNOVA system tended to underestimate distance stereoacuity by approximately 30 arc seconds compared to the FD2 test. If the INNOVA results were corrected by this amount, then there was a good correlation between the INNOVA results and the FD2. The Innova distance stereoacuity test underestimates stereopsis by approximately 30 arc seconds but does so with sufficient consistency that it may serve as an acceptable method of measuring distance stereoacuity. This study is the first that has correlated the Innova stereoacuity test with the FD2.

  12. High Accuracy Monocular SFM and Scale Correction for Autonomous Driving.

    Science.gov (United States)

    Song, Shiyu; Chandraker, Manmohan; Guest, Clark C

    2016-04-01

    We present a real-time monocular visual odometry system that achieves high accuracy in real-world autonomous driving applications. First, we demonstrate robust monocular SFM that exploits multithreading to handle driving scenes with large motions and rapidly changing imagery. To correct for scale drift, we use known height of the camera from the ground plane. Our second contribution is a novel data-driven mechanism for cue combination that allows highly accurate ground plane estimation by adapting observation covariances of multiple cues, such as sparse feature matching and dense inter-frame stereo, based on their relative confidences inferred from visual data on a per-frame basis. Finally, we demonstrate extensive benchmark performance and comparisons on the challenging KITTI dataset, achieving accuracy comparable to stereo and exceeding prior monocular systems. Our SFM system is optimized to output pose within 50 ms in the worst case, while average case operation is over 30 fps. Our framework also significantly boosts the accuracy of applications like object localization that rely on the ground plane.

  13. Relação entre acuidade visual e atividades instrumentais de vida diária em idosos em seguimento ambulatorial Relationship between visual acuity and instrumental activities of daily living of the elderly in clinical segment

    Directory of Open Access Journals (Sweden)

    Sheila de Melo Borges

    2010-06-01

    Full Text Available OBJETIVO: Avaliar a influêrcia da acuidade visual nas atividades instrumentais de vida diária em idosos em seguimento ambulatorial. MÉTODOS: Foram entrevistados, por meio de instrumento próprio, 64 idosos em seguimento ambulatorial num hospital universitário de Campinas/SP. Os sujeitos foram divididos em dois grupos, conforme os valores obtidos na medida da AV: o grupo I, composto pelos idosos com visão normal ou próxima do normal; e o grupo II, formado por aqueles com baixa visão. Foram realizadas correlações bivariadas entre as variáveis, a fim de identificar as seguintes relações entre os grupos de acuidade visual e as atividades instrumentais de vida diária. RESULTADOS: Foram observadas diferenças significativas entre os idosos com visão normal ou próxima do normal (grupo I e aqueles com baixa visão (grupo II, com respeito às variáveis. O grupo II apresentou maior dificuldade do que o grupo I no escore total do instrumento, bem como nas seguintes tarefas: uso do telefone, preparo de refeições, trabalhos manuais, lavar e passar roupa e tomar corretamente os remédios. CONCLUSÃO: Neste estudo, idosos com baixa visão de ambos os sexos apresentam maior dificuldade para realizar as AIVDs do que idosos com visão normal ou próxima do normal.OBJECTIVE: To evaluate the influence of visual acuity in instrumental activities of daily living in elderly patients in follow-up period. METHODS: through own instruments, sixty-four elderly men and women were interviewed in clinical segment at an academic hospital of Campinas/SP. They were then divided into two groups in accordance to the values that were obtained through the measure of the VA: the first group consisted of elderly people with normal vision or close to the normal, and the second group was formed of those with low vision. Bivariate correlations were made between the variables in order to identify the following relations: between groups of visual and instrumental

  14. Comparison of Subjective Refraction under Binocular and Monocular Conditions in Myopic Subjects.

    Science.gov (United States)

    Kobashi, Hidenaga; Kamiya, Kazutaka; Handa, Tomoya; Ando, Wakako; Kawamorita, Takushi; Igarashi, Akihito; Shimizu, Kimiya

    2015-07-28

    To compare subjective refraction under binocular and monocular conditions, and to investigate the clinical factors affecting the difference in spherical refraction between the two conditions. We examined thirty eyes of 30 healthy subjects. Binocular and monocular refraction without cycloplegia was measured through circular polarizing lenses in both eyes, using the Landolt-C chart of the 3D visual function trainer-ORTe. Stepwise multiple regression analysis was used to assess the relations among several pairs of variables and the difference in spherical refraction in binocular and monocular conditions. Subjective spherical refraction in the monocular condition was significantly more myopic than that in the binocular condition (p refraction (p = 0.99). The explanatory variable relevant to the difference in spherical refraction between binocular and monocular conditions was the binocular spherical refraction (p = 0.032, partial regression coefficient B = 0.029) (adjusted R(2) = 0.230). No significant correlation was seen with other clinical factors. Subjective spherical refraction in the monocular condition was significantly more myopic than that in the binocular condition. Eyes with higher degrees of myopia are more predisposed to show the large difference in spherical refraction between these two conditions.

  15. Comparison of Snellen acuity, VER acuity, and Arden grating scores in macular and optic nerve diseases.

    Science.gov (United States)

    Skalka, H W

    1980-01-01

    Patients with various macular and optic nerve abnormalities underwent Snellen acuity, transient VER acuity, and Arden grating testing. Snellen acuity was the coarsest of the 3 evaluations, generally falling after Arden scores and VER acuity had already undergone significant degradation. The Arden gratings appeared to be the most sensitive of the 3 tests, equalling VER performance in optic nerve diseases and surpassing it in macular diseases. Variations in results between the different tests are generally understandable if one considers the functions tested by each and the anatomical derangements caused by the diseases in question. The Arden grating test appears to be an excellent and sensitive screening test for central visual disturbances. Images PMID:7356929

  16. Resultados da correção cirúrgica de esotropias de grande ângulo, em portadores de baixa de acuidade visual unilateral Results of surgical treatment of large angle esotropia in patients with low visual acuity

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    Jorge Antonio Meireles-Teixeira

    2000-10-01

    Full Text Available Objetivo: Avaliar os resultados cirúrgicos de esotropias de grande ângulo (no mínimo 60 dioptrias prismáticas - dp, associadas à baixa de acuidade visual (BAV unilateral, cuja cirurgia foi planejada com o intuito de não se operar o olho de melhor visão. Casuística e Métodos: Foram selecionados 17 casos de esotropias não-acomodativas, associadas à BAV (AV 15 dp ou rotações de ± 4. Resultados: 13 (76,4% tinham AV de conta-dedos no olho não-fixador, 2 (11,7% atingiam 0,1 e outros 2 (11,7% 0,4. Em 3 havia alta miopia (equivalente esférico > ou = -6,00 dioptrias esféricas em ambos os olhos. Entre os 17 pacientes, 12 (70,5% obtiveram bom resultado cirúrgico, 3 (17,6% foram regulares e 2 (11,7% ruins. Conclusão: A cirurgia de estrabismo sob anestesia tópica mostrou ser eficaz e segura nestes casos especiais de BAV em um dos olhos, sendo que na maioria das vezes consegue-se não operar o olho de melhor visão; o que a nosso ver, só se tornou possível pelo uso da anestesia tópica.Purpose: To evaluate the surgical outcome of large angle esotropia (minimum of 60 prism diopters -- pd associated with unilateral low visual acuity (LVA in which the surgical strategy was applied in order to operate only the non-fixating eye. Patients and Methods: We selected 17 patients with non-accommodative esotropia, LVA (VA<= 0,4 in the non-fixating eye with the better visual correction and no previous treatment. Patients were classified as good result if they had a postoperative deviation of maximally 10 pd with binocular rotations of up to --2 of medial rectus and +2 of lateral rectus. Exotropia/esotropia between 10 and 15 pd or binocular rotations of ±3 were considered as a regular outcome. Deviations greater than 15 pd or binocular rotations of ±4 were included regarded as poor results. Results: Thirteen (76.4% patients had counts fingers VA in the non-fixating eye, 2 (11.7% achieved 0.1 and another two had 0.4. Three of them were also highly

  17. [Status of center point thickness and correlation between anatomic and best corrected visual acuity changes after photocoagulation, in diabetic macular edema].

    Science.gov (United States)

    Lima-Gómez, Virgilio; Razo Blanco-Hernández, Dulce Milagros

    2013-01-01

    Antecedentes: el grosor del punto central en pacientes con edema macular diabético cambia después del tratamiento, dependiendo del estado basal; se desconoce si esta variación reduce la correlación entre los cambios anatómicos y de capacidad visual. Objetivo: identificar la contribución del grosor del punto central basal a la correlación entre los cambios anatómicos y de capacidad visual, después de tratar el edema macular diabético. Material y métodos: estudio observacional, prospectivo, longitudinal y analítico, en diabéticos con edema macular tratados con fotocoagulación, estratificado por grupos: capacidad visual < 0.5 con (1) o sin engrosamiento central (2), y capacidad visual = 0.5 con (3) o sin engrosamiento central (4). Se identificó la correlación entre los cambios de grosor del punto central, volumen macular y capacidad visual (Spearman). Resultados: 79 ojos, 17 del grupo 1 (21.5%), 21 del 2 (26.6%), 14 del 3 (17.7%), 27 del 4 (34.2%). El grosor del punto central aumentó en los grupos 2 y 4, la capacidad visual disminuyó en el 3 y el volumen en todos. Las correlaciones entre el grosor del punto central y la capacidad visual en el grupo 3, y entre el volumen y la capacidad visual en el grupo 1 fueron negativas. La correlación de la muestra entre los cambios anatómicos y de capacidad visual fue baja (r= 0.14). Conclusiones: el aumento del grosor del punto central en ojos sin engrosamiento previo generó correlaciones opuestas entre grupos, y redujo la de la muestra. Estratificar conforme al grosor del punto central basal facilitaría identificar variables que afectan la respuesta terapéutica funcional.

  18. Visual impairment secondary to congenital glaucoma in children: visual responses, optical correction and use of low vision AIDS.

    Science.gov (United States)

    Haddad, Maria Aparecida Onuki; Sampaio, Marcos Wilson; Oltrogge, Ernst Werner; Kara-José, Newton; Betinjane, Alberto Jorge

    2009-01-01

    Congenital glaucoma is frequently associated with visual impairment due to optic nerve damage, corneal opacities, cataracts and amblyopia. Poor vision in childhood is related to global developmental problems, and referral to vision habilitation/rehabilitation services should be without delay to promote efficient management of the impaired vision. To analyze data concerning visual response, the use of optical correction and prescribed low vision aids in a population of children with congenital glaucoma. The authors analyzed data from 100 children with congenital glaucoma to assess best corrected visual acuity, prescribed optical correction and low vision aids. Fifty-five percent of the sample were male, 43% female. The mean age was 6.3 years. Two percent presented normal visual acuity levels, 29% mild visual impairment, 28% moderate visual impairment, 15% severe visual impairment, 11% profound visual impairment, and 15% near blindness. Sixty-eight percent received optical correction for refractive errors. Optical low vision aids were adopted for distance vision in 34% of the patients and for near vision in 6%. A manual monocular telescopic system with 2.8 x magnification was the most frequently prescribed low vision aid for distance, and for near vision a +38 diopter illuminated stand magnifier was most frequently prescribed. Careful low vision assessment and the appropriate prescription of optical corrections and low vision aids are mandatory in children with congenital glaucoma, since this will assist their global development, improving efficiency in daily life activities and promoting social and educational inclusion.

  19. Associations of Anisometropia with Unilateral Amblyopia, Interocular Acuity Difference and Stereoacuity in Preschoolers

    Science.gov (United States)

    Ying, Gui-shuang; Huang, Jiayan; Maguire, Maureen; Quinn, Graham; Kulp, Marjean Taylor; Ciner, Elise; Cyert, Lynn; Orel-Bixler, Deborah

    2012-01-01

    Purpose To evaluate the relation of anisometropia with unilateral amblyopia, interocular acuity difference (IAD) and stereoacuity, among Head Start preschoolers, using both clinical notation and vector notation analyses. Design Multicenter, cross-sectional study. Participants 3- to 5-year-old participants in the Vision In Preschoolers (VIP) Study (N=4040). Methods Secondary analysis of VIP data from participants who had comprehensive eye examinations including monocular visual acuity (VA) testing, stereoacuity testing, and cycloplegic refraction. VA was retested with full cycloplegic correction when retest criteria were met. Unilateral amblyopia was defined as IAD ≥2 lines in logarithm of the Minimum Angle of Resolution (logMAR). Anisometropia was defined as ≥0.25 D (diopter) difference in spherical equivalent (SE) or in cylinder power, and also two approaches using power vector notation. The percentage with unilateral amblyopia, mean IAD, and mean stereoacuity were compared between anisometropic and isometropic children. Main Outcomes Measures The percentage with unilateral amblyopia, mean IAD, and mean stereoacuity. Results Compared with isometropic children, anisometropic children had a higher percentage of unilateral amblyopia (8% vs. 2%), larger mean IAD (0.07 vs. 0.05 logMAR) and worse mean stereoacuity (145 vs.117 arc sec) (all pamblyopia, larger IAD, and worse stereoacuity (trend pamblyopia was significantly increased with spherical equivalent (SE) anisometropia >0.5 D, cylindrical anisometropia >0.25 D, the vertical/horizontal meridian (J0) or oblique meridian (J45) >0.125 D, or vector dioptric distance (VDD) >0.35 D (all pamblyopia than cylinder, SE, J0 and J45 (pamblyopia, larger IAD and worse stereoacuity. The threshold level of anisometropia at which unilateral amblyopia becomes significant was lower than current guidelines. VDD is more accurate than spherical equivalent anisometropia or cylindrical anisometropia in identifying preschoolers with

  20. Loss of Arc renders the visual cortex impervious to the effects of sensory experience or deprivation.

    Science.gov (United States)

    McCurry, Cortina L; Shepherd, Jason D; Tropea, Daniela; Wang, Kuan H; Bear, Mark F; Sur, Mriganka

    2010-04-01

    A myriad of mechanisms have been suggested to account for the full richness of visual cortical plasticity. We found that visual cortex lacking Arc is impervious to the effects of deprivation or experience. Using intrinsic signal imaging and chronic visually evoked potential recordings, we found that Arc(-/-) mice did not exhibit depression of deprived-eye responses or a shift in ocular dominance after brief monocular deprivation. Extended deprivation also failed to elicit a shift in ocular dominance or open-eye potentiation. Moreover, Arc(-/-) mice lacked stimulus-selective response potentiation. Although Arc(-/-) mice exhibited normal visual acuity, baseline ocular dominance was abnormal and resembled that observed after dark-rearing. These data suggest that Arc is required for the experience-dependent processes that normally establish and modify synaptic connections in visual cortex.

  1. Development of a clinically feasible logMAR alternative to the Snellen chart: performance of the "compact reduced logMAR" visual acuity chart in amblyopic children.

    Science.gov (United States)

    Laidlaw, D A H; Abbott, A; Rosser, D A

    2003-10-01

    The "compact reduced logMAR" (cRLM) chart is being developed as a logMAR alternative to the Snellen chart. It is closer spaced and has fewer letters per line than conventional logMAR charts. Information regarding the performance of such a chart in amblyopes and children is therefore required. This study aimed to investigate the performance of the cRLM chart in amblyopic children. Timed test and retest measurements using two versions of each chart design were obtained on the amblyopic eye of 43 children. Using the methods of Bland and Altman the agreement, test-retest variability (95% confidence limits for agreement, TRV) and test time of the cRLM and the current clinical standard Snellen chart were compared to the gold standard ETDRS logMAR chart. No systematic bias between chart designs was found. For line assignment scoring the respective TRVs were 0.20 logMAR, 0.20 logMAR, and 0.30 logMAR. Single letter scoring TRVs were cRLM (95% CL 0.17) logMAR, ETDRS (95% CL 0.14) logMAR, and Snellen (95% CL 0.29) logMAR. Median testing times were ETDRS 60 seconds, cRLM 40 seconds, Snellen 30 seconds. The sensitivity to change of the cRLM equalled or approached that of the gold standard ETDRS and was at least 50% better than that of Snellen. This enhanced sensitivity to change was at the cost of only a 10 second time penalty compared to Snellen. The cRLM chart was approximately half the width of the ETDRS chart. The cRLM chart may represent a clinically acceptable compromise between the desire to obtain logMAR acuities of reasonable and known sensitivity to change, chart size, and testing time.

  2. Prism therapy and visual rehabilitation in homonymous visual field loss.

    LENUS (Irish Health Repository)

    O'Neill, Evelyn C

    2011-02-01

    Homonymous visual field defects (HVFD) are common and frequently occur after cerebrovascular accidents. They significantly impair visual function and cause disability particularly with regard to visual exploration. The purpose of this study was to assess a novel interventional treatment of monocular prism therapy on visual functioning in patients with HVFD of varied etiology using vision targeted, health-related quality of life (QOL) questionnaires. Our secondary aim was to confirm monocular and binocular visual field expansion pre- and posttreatment.

  3. Central serous retinopathy with permanent visual deficit in a commercial air transport pilot: a case report.

    Science.gov (United States)

    Newman, David G

    2002-11-01

    This report describes a case of central serous retinopathy (CSR) in the right eye of a commercial air transport pilot which resulted in a permanent reduction in visual acuity and the loss of his license. The previously fit and well pilot developed sudden loss of central vision, which resolved spontaneously. He then went on to experience recurrent episodes of fluctuating visual acuity (down to 6/60) and visual dysfunction in the right eye. His left eye remained unaffected. Eventually his condition stabilized, and he was left with a permanent reduction in right visual acuity (6/36) with intact peripheral visual fields and a completely normal left eye. After a period of grounding of 12 mo, he sought to have his license reinstated. He was considered to be a functionally monocular pilot, and as such was granted a conditional Class 1 medical category. The aeromedical disposition of this pilot and the issues involved in determining the fitness to fly of pilots with permanent visual defects arising from CSR are discussed.

  4. Validation of Data Association for Monocular SLAM

    Directory of Open Access Journals (Sweden)

    Edmundo Guerra

    2013-01-01

    Full Text Available Simultaneous Mapping and Localization (SLAM is a multidisciplinary problem with ramifications within several fields. One of the key aspects for its popularity and success is the data fusion produced by SLAM techniques, providing strong and robust sensory systems even with simple devices, such as webcams in Monocular SLAM. This work studies a novel batch validation algorithm, the highest order hypothesis compatibility test (HOHCT, against one of the most popular approaches, the JCCB. The HOHCT approach has been developed as a way to improve performance of the delayed inverse-depth initialization monocular SLAM, a previously developed monocular SLAM algorithm based on parallax estimation. Both HOHCT and JCCB are extensively tested and compared within a delayed inverse-depth initialization monocular SLAM framework, showing the strengths and costs of this proposal.

  5. CLINICAL OBSERVATION OF CORNEAL CURVATURE AND CONTRAST VISUAL ACUITY BY RIGID GAS PERMEABLE CONTACT LENS%硬性角膜接触镜对圆锥角膜曲率和对比度视力的观察

    Institute of Scientific and Technical Information of China (English)

    韩联仪; 黄燕; 郑德海

    2011-01-01

    [目的]观察普通屈光不正和圆锥角膜患者配戴硬性角膜接触镜(RGPCL) 1~2年的视力矫正,对比敏感度,及角膜塑形效果.[方法]对66例(126只眼)6~32岁的患者进行验光,计算机辅助角膜地形图,角膜屈率计检查,对比敏感度观察戴框架眼镜和RGPCL矫正视力和视觉质量变化.[结果]总体平均近视球镜度(4.47±3.13)DS,平均柱镜度(3.91±2.39) DC.裸眼视力(0.18±0.18),戴框架镜较正视力(0.895±0.33),RGP矫正视力(1.06±0.24).戴RGPCL视力明显优于戴框架镜较正视力,两者差异具有统计学意义(P<0.05).角膜地形图各项值戴RGP-CL前后统计显示,戴RGP后角膜前表面陡峭K值(Ks),平均K值(AveK),角膜散光cyl,锥顶K值,均较戴RGPCL前降低,各项指标差异均具有统计学意义(P<0.05).对比敏感度全频段RGPCL均比框架镜明显升高.[结论]合理的配戴RGPCL,不仅可以获得较好的矫正视力,提高对比敏感度曲线,改善视觉质量.还可以获得显著的角膜塑形效果,有效控制圆锥角膜的进展.%[Objective] To investigate the effects on optical correction, contrast sensitivity and orthokeratology with rigid gas permeable contact lens (RGPCL) fitting 1-2 years in patients with ametropia and keratoconus. [Methods] Corrected visual acuity, comeal topography, cornea] curvature and contrast sensitivity were compared in 66 patients (126 eyes) of 6-32 years old with spectacles and RGPCL. [Results] The average spherical dioptre were (4.47±3.13) DS, cylindrical spherical were (3.91±2.39) DC. Uncorrected visual acuity were 0.18±0.18e, the mean corrected vision with spectacles and with RGPCL fitting were 0.895±0.33 and 1.06±0.24, respectively. The patients with RGPCL fitting got better corrected vision than those with spectacles, the differences between the two groups were statistically significant (P < 0.05). The comeal topography showed that the Ks, AveK, cyl and apex K value after RGPCL fitting

  6. Eye movements in chameleons are not truly independent - evidence from simultaneous monocular tracking of two targets.

    Science.gov (United States)

    Katz, Hadas Ketter; Lustig, Avichai; Lev-Ari, Tidhar; Nov, Yuval; Rivlin, Ehud; Katzir, Gadi

    2015-07-01

    Chameleons perform large-amplitude eye movements that are frequently referred to as independent, or disconjugate. When prey (an insect) is detected, the chameleon's eyes converge to view it binocularly and 'lock' in their sockets so that subsequent visual tracking is by head movements. However, the extent of the eyes' independence is unclear. For example, can a chameleon visually track two small targets simultaneously and monocularly, i.e. one with each eye? This is of special interest because eye movements in ectotherms and birds are frequently independent, with optic nerves that are fully decussated and intertectal connections that are not as developed as in mammals. Here, we demonstrate that chameleons presented with two small targets moving in opposite directions can perform simultaneous, smooth, monocular, visual tracking. To our knowledge, this is the first demonstration of such a capacity. The fine patterns of the eye movements in monocular tracking were composed of alternating, longer, 'smooth' phases and abrupt 'step' events, similar to smooth pursuits and saccades. Monocular tracking differed significantly from binocular tracking with respect to both 'smooth' phases and 'step' events. We suggest that in chameleons, eye movements are not simply 'independent'. Rather, at the gross level, eye movements are (i) disconjugate during scanning, (ii) conjugate during binocular tracking and (iii) disconjugate, but coordinated, during monocular tracking. At the fine level, eye movements are disconjugate in all cases. These results support the view that in vertebrates, basic monocular control is under a higher level of regulation that dictates the eyes' level of coordination according to context. © 2015. Published by The Company of Biologists Ltd.

  7. Monocular zones in stereoscopic scenes: A useful source of information for human binocular vision?

    Science.gov (United States)

    Harris, Julie M.

    2010-02-01

    When an object is closer to an observer than the background, the small differences between right and left eye views are interpreted by the human brain as depth. This basic ability of the human visual system, called stereopsis, lies at the core of all binocular three-dimensional (3-D) perception and related technological display development. To achieve stereopsis, it is traditionally assumed that corresponding locations in the right and left eye's views must first be matched, then the relative differences between right and left eye locations are used to calculate depth. But this is not the whole story. At every object-background boundary, there are regions of the background that only one eye can see because, in the other eye's view, the foreground object occludes that region of background. Such monocular zones do not have a corresponding match in the other eye's view and can thus cause problems for depth extraction algorithms. In this paper I will discuss evidence, from our knowledge of human visual perception, illustrating that monocular zones do not pose problems for our human visual systems, rather, our visual s