We compared the abilities of blind and sighted humans to distinguish grooved from smooth surfaces pressed against the stationary index fingertip. Ranging in age from 20 to 72 years, 37 blind and 47 sighted subjects participated in an automated two-alternative forced-choice tactile grating detection task. The tactile acuity of blind ...

PURPOSE: To determine the prevalence of blindness and visual impairment in adults aged 30 years and older in Pakistan and to assess socio-demographic risk factors. METHODS: Multistage, stratified (rural/urban), cluster random sampling, with probability proportional-to-size procedures, was used to select a nationally representative, cross-sectional sample of adults 30 years of ...

PURPOSE: To describe the change in visual acuity in a 15-year period. DESIGN: Population-based study. METHODS: setting: Beaver Dam, Wisconsin. participants: 4068 persons 43 to 86 years of age at the time of a baseline examination in 1988 to 1990, and with follow-up examinations every five years thereafter. observation procedures: ...

OBJECTIVE: To compare the diagnostic accuracy of the Moorfields regression classification (MRC) and subjective optic disc evaluation in discriminating early to moderate glaucomatous from nonglaucomatous eyes. DESIGN: Cross-sectional observational study. PARTICIPANTS: Two hundred thirty-three patients with glaucoma and 216 normal subjects were included in the analysis. Racial groups were defined ...

OBJECTIVE: To evaluate the prevalence of age-related maculopathy (ARM) in adult Chinese living in rural or urban regions of mainland China. DESIGN: Population-based prevalence study. METHODS: The study included 4439 subjects (aged 40 or more years) out of 5324 subjects invited to participate (response rate 83.4%). It was held in ...

Young (21-26 years, n=20) and old (55-86 years, n=25) participants were tested for their ability to recognize raised letters (6-mm high, 1-mm relief) by touch. Spatial resolution thresholds were also measured with grating domes to derive an index of the degree of afferent innervation at the fingertip. Letter recognition in ...

PURPOSE: To determine the values in decibels of retinal sensitivity within the central 26 degrees of the visual field of normal subjects divided into homogenous age groups using the Octopus 1-2-3; to compare the values of retinal sensitivity we have found with those considered normal in the statistical package obtained ...

PURPOSE: To analyze the variability of clinical and electrophysiological characteristics in X-linked choroideremia and provide the first report of a negative electroretinogram in choroideremia. DESIGN: Retrospective study. PARTICIPANTS: The records of 18 male patients with choroideremia and 8 female carriers were evaluated. METHODS: The data were reviewed regarding visual acuity ...

PURPOSE: To estimate the age at diagnosis of retinitis pigmentosa and to determine visual acuity deterioration, visual field impairment and the frequency of cataracts in Usher syndrome types 1 and 2. METHODS: We carried out a retrospective study of 328 affected subjects with Usher syndrome types 1 and 2. Study ...

PURPOSE: This study was designed to evaluate the minimum interocular correlation (IOC) needed by the visual system to correctly perceive a static stereoscopic stimulus as a function of normal aging. It was also our goal to evaluate the feasibility of clinical charts testing this aspect of visual perception. METHODS: Stereoscopic ...

For many populations the ability to move efficiently is compromised by an impaired muscular functioning. Strength development is necessary to overcome the effects of gravity to maintain posture and generate movement responses for mobility. The strength and power capabilities of individuals with total blindness (n = 12) were compared to ...

Purpose:We estimated the incidence and cost of accidental falls for the population with visual impairment, and the incidence and cost of falls directly attributable to visual impairment for the UK in 1999. Methods: A prevalence-based cost model of medical care was developed using national data for Accident and Emergency (A&E) ...

A 35 month old child was referred for electrophysiology testing with pendular nystagmus, corresponding head oscillations and reduced vision. Flash visual evoked potential (VEP) revealed large responses at the right occiput (but not the left occiput) from the right eye and similar large responses at only the left occiput from ...

The authors manipulated the circumstances in which individuals are typically embedded when standing upright by manipulating the intensity of light and the stationary structure of the environment. They expected that the manipulations would affect 12 older participants (aged 65-82 years) more than it would 12 younger participants (aged 22-24 years). ...

The current work examined age differences in the classification of novel object images that vary in continuous dimensions of structural shape. The structural dimensions employed are two that share a privileged status in the visual analysis and representation of objects: the shape of discrete prominent parts and the attachment positions ...

OBJECTIVE: To characterize the clinical course of retinal angiomatosis (RA) in von Hippel-Lindau (VHL) disease. DESIGN: Retrospective observational case series from a tertiary referral center. PARTICIPANTS: Fifty-seven consecutive VHL disease patients with RA with a mean follow-up of 7.3 years. METHODS: A retrospective chart review was performed to characterize the ...

OBJECTIVE: To enhance our understanding of coping and rehabilitation in the context of adaptation to disability by examining how coping may change over a two-year time period, and how different vision rehabilitation services may affect coping over time. DESIGN: Longitudinal two-wave study (baseline and two-year follow-up). SETTING: Vision rehabilitation agency. ...

The objective of the present study was to determine contrast sensitivity curves of concentric circular patterns with radial frequencies of 0.25, 0.5, 1.0, 2.0, and 4.0 cycles per degree in young and older adult volunteers. These parameters were also compared with sensitivity contrasts for sine-wave gratings. All participants had normal ...

AIM: To evaluate whether previous isotretinoin use induces permanent, measurable, and clinically significant abnormalities in night vision such that flying is precluded, and whether potential military and civilian commercial aviators should be screened routinely. METHODS: A retrospective, non-interventional, consecutive case series of 47 individuals with a confirmed history of oral ...

PURPOSE: This paper aimed to study the norms for clinical stereo-acuity in Saudi children aged between six and 12 years and to determine the 95 per cent confidence limits for stereo-acuity thresholds in this group of subjects. METHODS: A total of 1,383 normal subjects (883 male and 500 female) aged ...

AIM: To assess the repeatability of Eger macular stressometer (EMS) measures of photostress recovery and determine their association with other measures of visual function. METHODS: EMS photostress recovery time was measured in 90 patients with bilateral exudative age related macular degeneration (AMD), 19 with bilateral atrophic AMD and 47 with ...

BACKGROUND AND PURPOSE: Detection of longitudinal changes in white matter hyperintensities (WMH) by using visual rating scales is problematic. We compared a widely used visual rating scale with a volumetric method to study longitudinal white matter changes. METHODS: WMH were assessed with the visual Scheltens scale and a volumetric method ...

PURPOSE: This study was undertaken to determine whether grating acuity in early childhood can be used as a predictor of letter recognition acuity in patients with albinism. METHODS: In this retrospective study, we compared the binocular grating acuities of children with albinism (30 at age 1, 29 at age 2, ...

We tested the hypothesis that increases in minimal visual motor processing (VMP) time in older adults contribute to age-related increases in force variability. We manipulated the intermittency rate of visual information feedback over a 100-fold range as young (20-29 years old) and old (60-79 years old) participants produced isometric force ...

AIM: The purpose of this study was to evaluate the activity of Anterior Temporal, Masseter, Sternocleidomastoid and Anterior Digastric muscles in response to changes in visual input in subjects with defective vision by means surface electromyography. METHODS: A total of 20 children, aged between 7 and 13 years, were evaluated. ...

BACKGROUND: Conventional visual tests are not sensitive enough to detect low degree neural damage, as 6/6 (1.0) visual acuity can be upheld with less than two-thirds of the normal number of optic nerve axons. The aim of the current study was to evaluate the physiologic properties of a new computerised ...

PURPOSE: To estimate the prevalence and distribution of blindness and low vision in Northern China. DESIGN: Population-based cohort study. METHODS: The Beijing Eye Study included 4438 subjects with an age of 40+ years. Mean age was 56.2 +/- 10.6 years (range, 40 to 101 years). RESULTS: Forty-three (1.0%) individuals had ...

PURPOSE: To determine whether a sample of the 50-year-old and above population would provide comparable information to a total population-based survey. METHODS: In 1996, a national eye survey of the total population in The Gambia was undertaken and the results concerning the prevalence and distribution of blindness and low vision ...

OBJECTIVE: This study was conducted to assess dynamic visual acuity (DVA) under pupil dilation. BACKGROUND: Pupil dilation may negatively affect driving performance. METHODS: Thirty healthy young adults (mean age 29.4 years) with pupil dilation participated in this study as the Mydrin P group. In addition to them, 15 healthy young ...

BACKGROUND: Sociological and economic risk factors of visual impairment have never been described in France at a national level as the association between the number of ophthalmologists per inhabitant and visual impairment prevalence. METHODS: Two national surveys were pooled. First, 2075 institutions were selected at random from the French Health ...

Intraocular inflammatory diseases are collectively known as uveitis. The aetiology of this condition can be diverse, as inflammation may result from direct involvement of the uveal tract or indirect inflammation of adjacent tissues. Uveitis can present challenges to diagnosis and treatment, and is potentially a severe sight-threatening disease. In the ...

BACKGROUND: Prevention of visual impairment is an international priority agreed at the World Health Assembly of 2002--yet many countries lack contemporary data about incidence and causes from which priorities for prevention, treatment and management can be identified. METHODS: Registration as blind or partially-sighted in England and Wales is voluntary and ...

Vergence eye movements were recorded from three different populations: healthy young (ages 18-35 years), adaptive presbyopic and non-adaptive presbyopic(the presbyopic groups aged above 45 years) to determine how the variability of the eye movements made by the populations differs. The variability was determined using Shannon Entropy calculations of Wavelet transform ...

AIM: To examine how stereoacuity changes with age as measured by a variety of stereotests. METHODS: Stereoacuity has been measured in 60 normal subjects aged 17-83 years by a single observer using TNO, Titmus, Frisby near, and Frisby-Davis distance stereotests. Motor fusion was measured at (1/3) metre and 6 metres. ...

BACKGROUND: Although it is well known that age affects visual function, we still have much to learn about the impact of aging on binocular vision. Our aim was to establish distance heterophoria and distance fusional vergence ranges in a large non-clinical population of wide age range, to provide normal values ...

OBJECTIVE: This analysis of the results of 7 trials compared the taste and smell acceptability scores of cefdinir oral suspension and 4 other pediatric antibiotic oral suspensions--amoxicillin/clavulanate potassium, cefprozil, azithromycin, or generic amoxicillin--using a visual smile-face scale. METHODS: Data from 7 randomized, single-blind, cross-over trials were pooled and analyzed. In ...

PURPOSE: To estimate the prevalence rates of habitual visual acuity (VA) levels and visual impairment in Finland and to assess their correlation with self-reported visual function. DESIGN: Cross-sectional population-based study. PARTICIPANTS: Subjects were selected randomly from the Finnish population aged 30 years or older. Of 7979 eligible people, 7393 (93%) ...

The influence of aging and expertise on visual identification as function of semantic category (animals and tools) and spatial-frequency content of stimuli was investigated. Three-age groups of experts (whose profession required the use of manipulable tools) and non-experts, participated to the experiment. Data showed a different involvement of low and ...

PURPOSE: To monitor visual performance in early age-related maculopathy (ARM). METHODS: We measured monocular visual function-high-contrast visual acuity (HC-VA), central visual fields (mean sensitivity, MS), colour vision (desaturated Panel D-15), Pelli-Robson (P-R), and cone- and rod-mediated multifocal electroretinograms (mfERG) in 13 ARM subjects and 13 age-matched control subjects with normal ...

We studied the effects of aging on a speed discrimination task using a pair of first-order drifting luminance gratings. Two reference speeds of 2 and 8 deg/s were presented at stimulus durations of 500 ms and 1000 ms. The choice of stimulus parameters, etc., was determined in preliminary experiments and ...

PURPOSE: The purpose of this study was to assess face recognition ability in a large sample of elders (n=572, mean age=78.1 years) and to identify factors that affect performance. METHODS: Face recognition was measured by presenting standardized faces of varying sizes to simulate normal-sized faces at different viewing distances. Subjects ...

The present study evaluated the specific effects of motor demand and visual demands on the ability to control motor output in terms of performance and muscle activation. Young and elderly subjects performed multidirectional pointing tasks with the computer mouse. Three levels of mouse gain and three levels of target size ...

PURPOSE: To evaluate the effect of the menstrual cycle and gender on right and left visual hemifields in healthy subjects. METHODS: One randomly selected eye from each of 42 healthy normally menstruating women and of 37 men with no systemic and ocular problems, other than refractive error, were included in ...

Pattern-reversal and motion-onset visual evoked potentials (VEPs) were simultaneously tested in a group of 70 healthy subjects between the ages of 6-60 years to verify suspected differences in maturation and aging dynamics of the pattern and motion processing subsystems of the visual pathway. The motion-onset VEPs displayed dramatic configuration development ...

AIM: To estimate the incidence rates and major causes of registered blindness and low vision in Kuwait. METHODS: Data on age, gender and cause of blindness and low vision were collected from the Visual Disability Committee while evaluating Kuwaiti citizens applying for a blindness allowance from January 2000 to December ...

BACKGROUND: Tractable but undetected visual impairment in older people may be relatively common, particularly amongst the very old and in more deprived populations. Measurement of visual acuity is unlikely to be helpful in identifying this impairment, but targeted assessment of visual function may be beneficial. There is uncertainty about the ...

The luminance surrounding a computer display can potentially reduce visibility of the display (disability glare), result in sensations of discomfort (discomfort glare) and result in transient adaptation effects from fixating back and forth between the two luminance levels. The study objective was to measure the effects of surround luminance levels ...

In April 2004, The Eye Disease Prevalence Research Group published a series of articles that included age-specific estimates for the prevalence of low vision and blindness in whites, African Americans, and Hispanics living in the United States. Also included were age-, sex-, and ethnic-specific incidences of the following age-related eye ...

The aim of this study was to assess various aspects of visual function in 6 patients (age range: 9 months to 7 years and 8 months) with methylmalonic aciduria and homocystinuria. All patients had an ophthalmological examination and were tested with a battery of age-appropriate tests assessing various aspects of ...

Aging of visual pathways was measured psychophysically and physiologically in subjects aged 20-89 years. Contrast thresholds for the chromatic pathways increased with age, but there were no significant changes for thresholds of the achromatic pathway at low spatial frequencies. For visual evoked potential (VEP) responses, again only the chromatic pathways ...