Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Vision Tests”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,027 records · Page 57Linked to original sources
PubMed1979

Oculomotor abnormalities in Friedreich's ataxia.

A clinical neuro-ophthalmological and electro-oculographic study was made on fourteen patients with Friedreich's ataxia. None had evidence of optic nerve dysfunction. No patient complained of oscillopsia although all had ocular motor deficits of varying degrees, which appeared to be related to the severity of the general manifestations of the disease. The defects comprised square wave jerks, jerky pursuit with inability to maintain eccentric gaze resulting in gaze paretic nystagmus and rebound nystagmus. There was failure to suppress by fixation the vestibulo-ocular reflex. The slow phase velocity of caloric nystagmus was always of reduced velocity. There was inability to augment the slow phase velocity of optokinetic nystagmus with increasing stimulus velocity. Abnormalities of the saccadic system were manifest particularly as hypermetria. These signs in combination are suggestive of disease involving the cerebellar flocculus and vermis or their brain stem connections. No abnormalities were found in 17 parents or siblings.

Adolescent↗
PubMedDate not supplied

Hyper-vision in a patient with central and paracentral vision loss reflects cortical reorganization.

SM, a 21-year-old female, presents an extensive central scotoma (30 deg) with dense absolute scotoma (visual acuity = 10/100) in the macular area (10 deg) due to Stargardt's disease. We provide behavioral evidence of cortical plastic reorganization since the patient could perform several visual tasks with her poor-vision eyes better than controls, although high spatial frequency sensitivity and visual acuity are severely impaired. Between 2.5-deg and 12-deg eccentricities, SM presented (1) normal acuity for crowded letters, provided stimulus size is above acuity thresholds for single letters; (2) a two-fold sensitivity increase (d-prime) with respect to controls in a simple search task; and (3) largely above-threshold performance in a lexical decision task carried out randomly by controls. SM's hyper-vision may reflect a long-term sensory gain specific for unimpaired low spatial-frequency mechanisms, which may result from modifications in response properties due to practice-dependent changes in excitatory/inhibitory intracortical connections.

Acoustic Maculae↗
PubMed2001

Presumed sertraline maculopathy.

PURPOSE: To report a unique case of a woman who developed simultaneous bilateral maculopathy presumed to result from intake of sertraline hydrochloride, a serotonin reuptake inhibitor. METHODS: Full clinical ocular examination, color vision testing, automated static perimetry, electroretinography, electrooculography and fundus fluorescein angiography were performed. Living members of her family were also examined. RESULTS: The patient had normal electroretinography and electrooculography results. Automated static perimetry showed generalized reduction of sensitivity and central scotomas. Macular lesions resolved 6 months after discontinuation of sertraline, however, during twenty months of follow-up her visual acuity and abnormalities in other psychophysical tests did not improve. CONCLUSION: Patients started on sertraline should be informed of the potential risk of developing maculopathy, and they should be examined regularly to detect possible early alterations.

Electrooculography↗
PubMed2005

Reduced Stroop interference for opponent colors may be due to input factors: evidence from individual differences and a neural network simulation.

Sensory or input factors can influence the strength of interference in the classic Stroop color-word task. Specifically, in a single-trial computerized version of the Stroop task, when color-word pairs were incongruent, opponent color pairs (e.g., the word BLUE in yellow) showed reduced Stroop interference compared with nonopponent color pairs (e.g., BLUE in red). In addition, participants' color discrimination ability was measured by standard color vision tests (i.e., Farnsworth-Munsell 100-Hue Test and Ishihara plates). Error rates in the Farnsworth-Munsell test correlated positively with the amount of Stroop interference. Neural network simulations (variants of J. D. Cohen, K. Dunbar, & J. L. McClelland's, 1990, model) showed that only a distributed trichromatic input layer was able to simulate these findings. Thus, sensory input from the color system needs to be incorporated into current accounts of the Stroop effect.

Adult↗
PubMed1989

Preferential looking in the mentally handicapped.

We have assessed the feasibility of Preferential Looking (PL), using Teller Acuity Cards, for the estimation of binocular and monocular visual acuities in a group of mentally handicapped adults. Our results show the comparison between grating and recognition acuities, inter-observer variation, success rate, time taken and the sensitivity of this method in identifying monocular visual deficit in this group of subjects. The reasons for success or failure with PL methods in relation to criteria for mental handicap are discussed.

Adult↗
PubMed1992

A scoring method for Hess charts.

A new scoring system for Hess charts is described. Scores for both horizontal and vertical deviations are calculated from the displacement of individual points on the Hess chart, using weighting factors for the centre, inner and outer zones. The scoring system was validated in a group of 24 patients undergoing surgery for paralytic or restrictive strabismus. Subjective scores were obtained from patients both before and after corrective surgery, and corresponding Hess charts were scored using the new system. There was a good correlation between the changes in subjective and objective score. Our scoring system has applications in both research and clinical practice, allowing objective analysis of changes in muscle balance in a variety of motility disorders.

Diplopia↗
PubMed1996

Colour contrast thresholds are normal in functional amblyopia.

We evaluated colour contrast thresholds in patients with unilateral functional amblyopia. A computer-controlled colour vision test was used to determine colour contrast thresholds along a blue-yellow tritan axis. Prior to the threshold measurement, a heterochromatic flicker brightness test was performed to ensure isoluminance between the test stimulus and the background for every subject individually. Luminance contrast thresholds were also measured using the same computer-based system. Twenty amblyopic patients were tested. All showed normal tritan colour contrast thresholds both for their amblyopic eye and non-amblyopic fellow eye. Luminance contrast thresholds were elevated in all 6 refractive amblyopic eyes, in 4 of 9 strabismic eyes and in 2 of 5 mixed amblyopic eyes. Colour contrast thresholds are normal in functional amblyopia (with central fixation). Whenever elevated tritan colour contrast thresholds are found in patients with a decreased visual acuity, other causes of visual impairment are to be evaluated.

Adolescent↗
PubMed1996

Does stereopsis matter in humans?

Stereopsis has been one of the most popular fields of vision research for well over a century and is routinely measured in clinical practice, yet its functional significance has been largely neglected. Stereopsis is disrupted by blur, amblyopia and strabismus and is of potential value as a means of indirect screening for visual disorders in childhood. However, evidence for the functional effects of stereoscopic deficits is sparse. Recent investigations indicate that binocularity is an advantage in certain tasks, especially in the comprehension of complex visual presentations and those requiring good hand-eye coordination. The assumption derived from the evolutionary theory that stereopsis represents an adaptation by primates to arboreal life needs to be questioned. While the functional aspects of stereopsis are still not fully understood the direction that future research should take to unravel this important issue is apparent.

Adult↗
PubMed2004

Macular coloboma in siblings affected by different phenotypes of retinitis pigmentosa.

Purpose To report the clinical association between macular coloboma (early-onset macular dystrophies/atrophic changes) and different phenotypes of retinitis pigmentosa (RP). Methods Three young-adult siblings, two males and one female, were retrospectively studied. These patients underwent two complete ophthalmologic examinations (27-month follow-up), including orthoptic evaluation, colour vision test, visual field, corneal topography, electronystagmography, fluorescein angiography, and electroretinography. Eye check, automated visual field test, and complete electroretinographic study were also conducted on other asymptomatic members of the same family. Results All symptomatic siblings were affected by manifest congenital nystagmus, poor visual acuity, and progressive visual field impairment in both eyes, bilaterally presenting macular coloboma associated with three different RP patterns: classic RP; mild dystrophy of the retinal pigment epithelium, associated with subnormal electroretinographic findings (subclinical form of RP); and sector RP. The ophthalmologic reports regarding their deceased father documented that he had suffered from the same alterations of ocular movements and visual performances diagnosing, in both eyes, extensive atrophic changes of the macular area completely surrounded by pigmented bone spicules (RP-type tapeto-retinal dystrophy). The other investigated relatives did not show any specific and/or significant ocular disorder. Conclusions In these three adult members of the same family, the concomitance between macular coloboma and different intrafamilial RP phenotypes is described. This association represents an autosomal dominant clinical entity, hitherto observed only in non familial sporadic cases.Eye (2004) 18, 421-428. doi:10.1038/sj.eye.6700689

Adult↗
PubMed2006

Impact of differences between eyes on binocular measures of vision in patients with cataracts.

PURPOSE: To assess the association of stereopsis with differences between eyes (better minus worse eye value) and the binocular value of visual acuity and contrast sensitivity, and to analyse binocular summation or inhibition phenomena owing to differences between eyes. METHODS: A cohort of 137 patients with bilateral cataracts (visual acuity of 0.3 LogMAR or worse in both eyes) was followed up through first- and second-eye cataract surgery. The patients were recruited from the ophthalmology departments of two teaching hospitals. Visual acuity, contrast sensitivity (monocular and binocular), and stereopsis were measured preoperatively, after first- and second-eye surgery. Multiple linear regression and local correlation analyses were used. RESULTS: Stereopsis was most strongly influenced by visual acuity in the postoperative period after first-eye surgery (standardized coefficients of 0.382 for difference between eyes and 0.356 for binocular visual acuity) and by contrast sensitivity in the postoperative period after second-eye surgery (standardized coefficients of 0.353 for the difference between eyes and -0.312 for binocular contrast sensitivity). After first-eye surgery, the correlation of the differences between eyes with stereopsis was stronger (between 0.4 and 0.5) when the differences were greater than 0.4 logMAR units for visual acuity. Slight binocular summation was found for contrast sensitivity. CONCLUSIONS: When assessing the indication for and outcomes of cataract surgery, analysis of visual function should include measures of both eyes, rather than measures of the operative eye only, as differences between eyes (better minus worse eye value) may play an important role in binocular measures such as stereopsis.

Aged↗
PubMed2000

A measure of handicap for low vision rehabilitation: the impact of vision impairment profile.

This study aims to further develop the Impact of Vision Impairment (IVI) profile into a practical, valid instrument for use in low vision rehabilitation. The IVI item pool was derived from focus groups of people with impaired vision, relevant content of existing quality of life questionnaires, and the administration of two trial versions. The second trial version of IVI was administered to 256 people who were vision impaired. Items were deleted if they were of little or no concern or were unable to be performed by most people, had moderate to high inter-item correlation, or did not contribute to a factor in the factor analysis. Two items were deleted due to floor and ceiling effects, 11 due to moderate to high inter-item correlation r> or =0.6. None were removed as a result of factor analysis. The first three factors explained 59% of the variance.This reduced version of the IVI, a tool able to determine rehabilitation needs for people who are vision impaired, will now undergo its final validation procedures.

Adult↗
PubMed2000

Royal Australian College of Ophthalmologists and Royal Australian College of General Practitioners National GP Eye Skills Workshops: colleges and divisions reskilling general practice.

PURPOSE: Little formal eye skills training has historically been available to Australian general practitioners at undergraduate or postgraduate levels. The development of the National GP Eye Skills Workshop was a joint initiatve of the Royal Australian Colleges of General Practice and Ophthalmology, to enhance the skills of Australian general practitioners in a range of important ocular examination and procedural areas. METHODS: Workshops were run in eight Queensland Divisions of General Practice in 1998. Between two and 10 local ophthalmologists in each divisional area were involved ether in the workshop programme or in the recruitment of patients for the patient assessment module. Workshops were run on weekends and included modules on vision testing and disease screening in children and adults, ophthalmoscopy, assessment for glaucoma and diabetic retinopathy, incision of chalazions, removal of corneal foreign bodies, ocular first aid, implementing eye assessment in busy general practice, and a patient assessment clinic. A questionnaire was administered which was comprised of sections relating to the format of the workshop, new skills and concepts learnt, learning exceptions, and perception of future ability to treat/scan/assess for eye conditions in general practice. The questionnaire was completed by 91% of participants. RESULTS: Participants strongly supported the impact of the workshop on their ability to detect and treat eye problems in their practices, and refer where appropriate to an ophthalmologist. They also rated highly all individual aspects of the programme in terms of impact on their delivery of general practitioner eye care. CONCLUSIONS: The results illustrate the comprehensive success of the workshop programme in format, content, relevance and delivery.

Adult↗
PubMed1999

Spectral sensitivity in hemianopic macaque monkeys.

We measured the increment threshold sensitivity to 2 degrees, 200-ms targets presented at a lateral and radial eccentricity of approximately 20-26 degrees in both visual hemifields of three macaque monkeys whose left striate cortex had been removed 5 years earlier, and in one normal control. As in patients with blindsight, sensitivity of the hemianopic field for blue, green and red stimuli was reduced by as little as 0.5 log units. With increasing light adaptation from scotopic to mesopic to photopic levels, there was a progressive increase in the sensitivity to long wavelengths relative to that for short and medium wavelengths. This shift in relative sensitivity ('Purkinje shift') shows that rod and cone mechanisms operate in both the normal and hemianopic fields and that the sensitivity that remains following removal of striate cortex is not mediated exclusively by rods.

Adaptation, Ocular↗
PubMed1995

Differences in visual acuity between the eyes: determination of normal limits in a clinical population.

We determined the difference in visual acuity between the right and left eyes of patients and also determined the maximal level of acuity expected in a group of visually normal individuals. Visual acuity was measured in the right and left eyes of 72 subjects aged from 16 to 67 years using Bailey-Lovie type charts. The chart was read until fewer than three letters were read on a line and acuities were based on each letter correct contributing -0.02 to the overall score. For 12 of these subjects, visual acuity was measured a further four times. Average visual acuities for right and left eyes were -0.137 and -0.126log MAR, respectively. The signed visual acuity difference was normally distributed and had a standard deviation of 0.050log MAR. The mean visual acuity difference for the 12 subjects for whom the measures were repeated was 0.033log MAR (SD of the signed visual acuity difference: 0.049log MAR). We conclude that if a patient has a difference in visual acuity between the two eyes of more than 5 letters on a Bailey-Lovie style chart, further investigation is indicated.

Adolescent↗
PubMed2002

Temporal detection in human vision: dependence on eccentricity.

Studies of human perception of time-varying luminance often aim to estimate either temporal impulse response shapes or temporal modulation transfer functions (MTFs) of putative temporal processing mechanisms. Previously, temporal masking data have been used to estimate the properties and numbers of these temporal mechanisms in central vision for 1 cycle per degree (cpd) targets [Fredericksen and Hess (1998)]. The same methods have been used to explore how these properties change with stimulus energy [Fredericksen and Hess (1997)] and spatial frequency [Fredericksen and Hess (1999)]. We present here analyses of the properties of temporal mechanisms that detect temporal variations of luminance in peripheral vision. The results indicate that a two-filter model provides the best model for our masking data, but that no multiple filter model provides an acceptable fit across the range of parameters varied in this study. Single-filter modelling shows differences between processing mechanisms at 1 cpd in central vision and those that operate eccentrically. We find evidence that this change is because of differences in relative sensitivities of the mechanisms, and to differences in fundamental mechanism impulse responses.

Electronics↗
PubMed2002

Spherical and irregular aberrations are important for the optimal performance of the human eye.

Contrast sensitivity measured psychophysically at different levels of defocus can be used to evaluate the eye optics. Possible parameters of spherical and irregular aberrations, e.g. relative modulation transfer (RMT), myopic shift, and depth of focus, can be determined from these measurements. The present paper compares measured results of RMT, myopic shift, and depth of focus with the theoretical results found in the two eye models described by Jansonius and Kooijman (1998). The RMT data in the present study agree with those found in other studies, e.g. Campbell and Green (1965) and Jansonius and Kooijman (1997). A new theoretical eye model using a spherical aberration intermediate between those of the eye models described by Jansonius and Kooijman (1998) and an irregular aberration with a typical S.D. of 0.3-0.5 D could adequately explain the measured RMT, myopic shift, and depth of focus data. Both spherical and irregular aberrations increased the depth of focus, but decreased the modulation transfer (MT) at high spatial frequencies at optimum focus. These aberrations, therefore, play an important role in the balance between acuity and depth of focus.

Adaptation, Ocular↗