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PubMed1980

Visual acuity measured with pupil responses to checkerboard stimuli.

The response of the pupil was measured to a foveally fixated small field in which checkerboards were alternated with a blank field of equal average luminance. The subjects studied had refractive errors, but their eyes were free from pathological changes. A pupil visual acuity could be derived, which showed a very high correlation with the subjective acuity with the same checkerboard stimuli. The method of obtaining pupil visual acuity seems to compare favorably with other objective methods of measuring visual acuity.

Adolescent↗

PubMed1979

Panoramic viewing, visual acuity of the deviating eye, and anomalous retinal correspondence in the intermittent exotrope of the divergence excess type.

Monocular visual acuities in a binocular field of view, field of view under binocular conditions, and retinal correspondence were investigated in five intermittent exotropes of the divergence excess type. Results indicated that all five intermittent exotropes demonstrated (1) normal visual acuity in the deviating eye without suppressing the fixating eye, (2) a lateral extension of the temporal field of view (panoramic viewing), (3) anomalous retinal correspondence.

Adolescent↗

PubMed2005

Impairment of visual acuity and reading performance and the relationship with cataract type and density.

PURPOSE: To evaluate the association between the density of nuclear, cortical, and posterior subcapsular lens opacities and visual impairment in patients with cataract. METHODS: In 80 patients, visual acuity and reading performance were evaluated 1 day before and 4 weeks after cataract surgery. Cataracts were categorized and graded according to the Lens Opacities Classification System (LOCS) III of nuclear color (NC), nuclear opalescence (NO), cortical (C), and posterior subcapsular cataract (P). A multiple linear regression analysis and partial correlation coefficients were calculated. Data were also checked for significant pre- and postoperative differences in visual performance related to cataract grading. RESULTS: In the multiple linear regression analysis, significant associations were found between the improvement in visual acuity and reading performance after cataract surgery and the NC, NO, and P scores (P < 0.001); no significant association was found for the C score (P > 0.05). High partial correlation coefficients were found between the P score and the preoperative visual acuity (r = 0.6; P < 0.001), reading acuity (r = 0.74; P < 0.001), and maximum reading speed (MRS; r = -0.77; P < 0.001). Significant but lower partial correlation coefficients were found for the NO score. No significant partial correlation coefficients were found for the NC and C score. Significant pre- and postoperative differences in MRS were found in patients with P scores > or =3 or NO and NC scores > or =5, representing functionally relevant impairment. CONCLUSIONS: A strong association was found between visual impairment in patients with cataract and the severity of posterior subcapsular cataract (PSC) and nuclear opacity. Particularly in patients with PSC, deficits in reading performance significantly increased. The functionally relevant deficits in patients with P scores > or =3 or NO and NC scores > or =5, should be carefully considered for planning cataract surgery or visual rehabilitation.

Aged↗

PubMed1992

["Glare vision". II. Study of visual acuity of glare sensitive patients in increasing test field luminance].

Sensitivity to glare is an unspecific ophthalmological symptom that can be caused by different anatomical structures; it can be related to optical and to cortical structures, it also can be due to defects in the neuronal mechanisms of the retina that control adaptation processes. In many cases the exact mechanisms are still unknown. Tests of visual acuity in glare sensitive patients with increasing test field luminance reveal-depending on the underlying disease-several types of variations from the normal visual-acuity-function that was determined over a wide range of light intensity from 0.1 to 30,000 cd/m2. Marked changes in the visual acuity-luminance-function at high test field intensities were found primarily in patients with retinal diseases, particularly in disturbances of the cone system. These visual acuity losses at high test field luminances can be explained by major functional impediments of the neuronal adaptive mechanisms at the retinal level. Less apparent were the changes in visual acuity-luminance-function in cases of optic nerve diseases. According to our studies changes in the visual acuity-luminance-function accompanied with high glare sensitivity are most often due to pathological changes in neuronal circuitry of the retina, less often to the effects of stray light. This test therefore can provide an important criterion for establishing the correct diagnosis.

Adolescent↗

PubMed1992

Visual acuities and scotomas after one week levodopa administration in human amblyopia.

The authors previously showed that a single dose of levodopa improves the contrast sensitivity and decreases the size of fixation point scotomas in amblyopic patients. In the present study, they investigated the effect of levodopa after 1 wk of daily administration using a cross-over, double masked design. The decrease of fixation point scotomas was confirmed with automatic static perimetry. An improvement of visual acuity occurred in 70% of the patients after 1 wk of levodopa administration compared to only 22% in the authors' previous study using one single dose. The improvements in visual acuities and visual fields persisted even after the levodopa administration was completed.

Administration, Oral↗

PubMed2002

Do poor nutrition and display screens affect visual acuity in children?

Two studies conducted in Scotland have shown an increase in visual acuity (VA) screening failure among primary school-aged children in recent years. Two other trends were observed during the same period - an increase in children bringing packed lunches to school, and increased access to display screen equipment (DSE) including television, computers and hand-held computer games. This study set out to assess if either DSE use of poor diet could be linked with visual acuity screening failure in Scottish primary school children. Information was collected on diet and DSE use from 1384 children who had received VA screening in eight primary schools in Glasgow. After controlling for deprivation, DSE use other than watching television was associated with an increased risk of VA screening failure, as was a 'poor' diet. If these findings are confirmed by other studies and a causal link can be made, then health education at school could be designed to prevent VA screening failure.

Child↗

PubMed1996

Change in visual acuity associated with cataract surgery. The Beaver Dam Eye Study.

PURPOSE: Cataract is the most common age-related eye disease in most countries worldwide. However, unlike many age-related eye diseases, therapy, in the form of cataract surgery, is successful in restoring at least some function in the vast majority of patients. The purpose of this investigation is to evaluate the change in vision related to specific kinds of cataract and cataract surgery in a population-based study in Beaver Dam, Wisconsin. METHODS: The data are derived from the Beaver Dam Eye Study, a population-based incidence study of age-related eye disease. Participants were seen for their baseline evaluation (n = 4926) between March 1, 1988, and September 14, 1990, and for a follow-up examination (n = 3684) an average of 4.8 years later. All examinations, interviews, lens photography, and grading were performed using standard protocols. The age range was 43 to 84 years at the census preceding the baseline examination. RESULTS: For those with no cataract at baseline and without cataract surgery at follow-up, there was an average decline of 0.5 letters (on a logMAR scale) in the right eye by the follow-up examination. In persons with any cataract at baseline and without cataract surgery at follow-up, there was a decrease of four letters. When cataract surgery was done in the interval, it was associated with a significant (P < 0.0001) nine-letter (2-line) improvement in visual acuity. CONCLUSION: Cataract surgery in this population was associated with a significant improvement in visual acuity. It is appropriate to evaluate visual acuity, cataract, and visual needs in planning for eye care in aging populations.

Adult↗

PubMed2002

Changes in visual acuity of patients undergoing cataract surgery during the last two decades.

PURPOSE: To compare preoperative visual acuities in patients who underwent cataract surgery between 1982 and 2000. METHODS: Information on visual acuity (VA), ocular disease and general disease was obtained from records relating to samples of consecutive cataract operations in 1982, 1985, 1990, 1995 and 2000 in two hospitals in the Vaasa region of Finland. RESULTS: Between 1982 and 2000, the average preoperative VA in the operated eye increased by 0.85 logMAR units (from logMAR 1.56 to logMAR 0.71) or 8.5 log lines. Corresponding decimal values are 0.03 and 0.2, respectively. In the better eye, VA increased from logMAR 0.64 to logMAR 0.37. Corresponding decimal values are 0.23 and 0.43, respectively. The incidence of cataract surgery increased from 1.0 to 7.2 operations per 1000 of the population per year over the period. For an annual increase of one operation per 1000 inhabitants, the increase in average VA before surgery is 1.3 log lines in the operated eye and 0.4 log lines in the better eye. The number of patients with visual impairment (WHO definition: VA < 0.3) before surgery fell from 47% to 15%, and the number of patients with profound visual handicaps (VA < 0.1) before surgery fell from 15% to 4%. CONCLUSION: The preoperative vision of patients undergoing cataract surgery during the last two decades has improved significantly. Preoperative VA has increased linearly in line with the incidence of surgery. Only a small proportion of the increase in incidence of cataract surgery can be explained by the increasing average age of the population.

Adult↗

PubMedDate not supplied

A case of Vogt-Koyanagi-Harada disease with good visual acuity in spite of subfoveal fold.

BACKGROUND: Vogt-Koyanagi-Harada (VKH) disease patients with the complication of subretinal pigmented proliferative tissue tend to have a poor visual prognosis. CASE: We herein report a case of VKH with good visual acuity despite a prominent subretinal fold. OBSERVATIONS: A 24-year-old woman, who experienced several recurrent episodes of VKH disease, had bilateral serous retinal detachment with poor vision (RE 20/40 and LE 20/25). After the administration of high doses of systemic corticosteroids and D-mannitol, the subretinal fluid disappeared and the sensory retinas gradually became reattached. During the course of therapy, prominent pigmented subretinal strands were formed in both eyes. Optical coherence tomography disclosed that the strands existed at the retinal pigment epithelium level. Amazingly, we observed a change in the location of the fold in the posterior retina during the course of the disease. The patient finally showed the "sunset glow" fundi and a subretinal fold that was located almost directly beneath both fovea. Fortunately, this patient was able to recover and finally achieve a good visual acuity (RE 20/17 and LE 20/17). CONCLUSION: We reported a VKH disease patient with a good visual acuity despite a remarkable subfoveal fold, which changed its location during the course of the disease.

Adrenal Cortex Hormones↗

PubMed1996

Reliability of visual acuity in children with reduced vision.

We examined the test-retest reliability of visual acuity in 18 children referred to the Hospital Eye Service with reduced vision. Unaided distance acuities were recorded, using logarithmically scaled letter charts, on two occasions separated by an interval of one week during which no clinical intervention took place. Coefficients of repeatability were found to be +/- 0.25 and +/- 0.21 log units in left and right eyes, respectively. A further analysis of 14 subjects' data each of whom had one eye with consistently poorer acuity in both test sessions yielded coefficients of repeatability of +/- 0.15 and +/- 0.22 log units in, respectively, the better and poorer eyes. The reliability of visual acuity recorded in the better eye closely approximates to that previously found in normal adults, whilst that of the poorer eye appears more comparable to that of adult clinical populations.

Child↗

PubMed1999

Ophthalmological follow up of preterm infants: a population based, prospective study of visual acuity and strabismus.

BACKGROUND/AIMS: Prematurely born infants are known to have an increased rate of ophthalmological morbidity. The aim of the present study was to investigate visual acuity and ocular alignment in a population of preterm infants in a geographical area, in infants with and without retinopathy of prematurity (ROP). METHODS: A prospective population based study of ophthalmological status of preterm infants with a birth weight of 1500 g or less was performed during 3.5 years, with examinations at 6, 18, 30, and 42 months of corrected age. Visual acuity was tested using linear optotypes. Multiple regression analyses were used to analyse independent risk factors for poor vision and strabismus. RESULTS: Poor vision (< 0.3) was detected in 2.5% (6/237) of the children. Of these, only two (0.8%) had a severe visual impairment (< 0.1). Strabismus occurred in 13.5% (31/229). Children with cryotreated ROP and neurological complications ran the highest risk of poor vision and strabismus, according to multiple regression analysis. Among children without a history of ROP or neurological complications, 34% had a visual acuity < 0.7 and 5.9% had strabismus, compared with 61% and 22%, respectively, among the children with ROP or neurological complications. CONCLUSIONS: The overall incidence of subnormal vision and strabismus in children born prematurely was higher than in a full term population of the same age. On the basis of this study, follow up of all preterm infants screened for ROP is recommended and general guidelines are suggested.

Birth Weight↗

PubMed1991

A new set of variable-contrast visual acuity charts.

Using a computer plotting technique, we designed four variable-contrast visual acuity charts. The contrast of the first 3 is 90, 15, and 2.5%, respectively. The fourth is 90%, but the luminance of the optotypes and background are the reverse of the first chart. The main features of these charts are as follows. Both contrast sensitivity and spatial frequency are in geometric gradation, which observes the laws of Weber and Fechner. The mean average luminance, (Lmax + Lmin)/2, is constant for all four charts, which follows the concept of contrast sensitivity function (CSF). Charts 1 and 4, which have the same contrasts but different glare backgrounds, measure the glare that is related to the transparency of the refractive media of the eye. Because the charts are rotatable, patient memorization and guessing are minimized. Results compared with those of the conventional visual acuity test and are understandable by patients and eye care practitioners. The charts, which are simple, easy, and require little time, are inexpensive and portable.

Adult↗

PubMed1999

Enlargement of atrophy and visual acuity loss in the geographic atrophy form of age-related macular degeneration.

OBJECTIVE: To describe the progression of geographic atrophy (GA) from age-related macular degeneration (AMD) with respect to visual acuity (VA) loss and enlargement of atrophy. DESIGN: A prospectively observed case series. SETTING: Tertiary retinal referral center. PARTICIPANTS: One hundred twenty-three patients with GA due to AMD who completed at least 1 year of follow-up (median follow-up, 3 years) were examined annually. METHODS: At each examination, a protocol best-corrected VA of each eye was measured, a clinical examination was performed, and color fundus photographs were taken. The areas of atrophy were drawn and measured. MAIN OUTCOME MEASURES: Visual acuity loss and enlargement of total and central atrophy. RESULTS: At baseline, median VA was poorer with larger areas of atrophy, but there was wide variation related to sparing of the fovea. Thirty-one percent of all study eyes suffered a three-line VA loss from baseline by 2 years, and 53% had a three-line loss by 4 years. Those eyes with VA better than 20/50 had the highest rate of acuity loss; 27% of these eyes had acuities of 20/200 or worse at 4 years. Visual acuity loss in the GA study eye was similar in patients with bilateral GA and in those with choroidal neovascularization in the fellow eye. Total atrophy enlarged a median of 1.8 Macular Photocoagulation Study disc areas (DA) at 2 years; atrophy within a 4-DA circle centered on the fovea enlarged a median of 0.9 DA. Two (22%) of nine patients with GA in one eye and only drusen without advanced AMD in the fellow eye developed GA in the fellow eye at 2 years. CONCLUSIONS: Geographic atrophy is associated with a significant decline in VA over time in many eyes. Areas of atrophy continue to enlarge over time, even when already large at baseline. The combination of reduced VA with enlargement of atrophy, occurring bilaterally in most patients, can lead to significant impairment of visual function.

Aged↗

PubMed1990

Stereoscopic eye exercises and visual acuity.

The present study was done to investigate the effects of stereoscopic eye exercises on visual acuity, testing 20 college students (9 men and 11 women, ages 18 to 35 yr.). Visual acuity was assessed before and after the exercises through six tests: far vision--both eyes, right eye; left eye; and near vision--both eyes, right eye, left eye. Statistically significant improvements were found on five of the six pretest-posttest comparisons: far vision--both eyes, right eye, and left eye; and near vision--both eyes, right eye, and left eye. Changes in far vision, right eye only approached significance. Limitations of the present study were discussed, and recommendations for research were presented.

Adolescent↗

PubMed2005

Random measurement error in visual acuity measurement in clinical settings.

PURPOSE: To estimate the random measurement error in visual acuity (VA) determination in the clinical environment in cataractous, pseudophakic and healthy eyes. METHODS: The VAs of patients referred for cataract surgery or consultation by ophthalmic professionals were re-examined and the VA results for distance using projector acuity charts were compared. Refractive errors were also remeasured. A total of 99 eyes (41 cataractous, 36 pseudophakic and 22 healthy eyes) were examined. The healthy comparison group consisted of hospital staff. Only one eye of each person and eyes with Snellen VAs of 0.3-1.3 (logMAR 0.52 to - 0.11) were included. The mean time interval between the first and second examinations was 45 days. RESULTS: The estimated standard deviation of measurement error (SDME) of repeated VA measurements of all eyes was logMAR 0.06. Eyes with the lowest VA (0.3-0.45) had the largest variability (SDME logMAR 0.09), and eyes with VA > or = 0.7 had the smallest (SDME logMAR 0.04). The variability may be partly explained by the line size progression in lower VAs, partly by the difference in the remeasurement of the refractive error. The difference in the average VA between examinations 1 and 2 (logMAR 0.15 versus 0.12) was considered to be of some interest because it indicates that some learning effect is possible. CONCLUSION: Visual acuity results in clinical settings have a certain degree of inherent variability. In this series variability ranged from SDME logMAR 0.04 (eyes with good vision) to logMAR 0.09 (in the lower vision group) in the Snellen VA range of 0.3-1.3. Changes should be judged with caution, especially in cases of decreased VA.

Adult↗

PubMed1995

Polarising light biomicroscopy and the relation between visual acuity and cataract.

The use of polarised light in biomicroscopy allows discrimination of lenticular features which are not discernible using standard biomicroscopic techniques. However, just as is true of most brightness-dependent photographic methods testing the effect of filters, past uses of polarised light did not involve any control of illumination. The present study involved the use of polarised light in the photo-biomicroscopy of the anterior segment in cataract patients, the consequential loss in illumination being mimicked with different neutral density filters. This served to distinguish between polarisation and attentuation. The patients were refracted and their corrected visual acuity was recorded. A qualitative scale was drawn up ranking weights of lenticular opacities. Spearman's rank correlation was applied to the photographs obtained with conventional and polarised-light biomicroscopy in turn. Brightness control served to confirm that biomicroscopy with polarised light offers some advantages over conventional methods, and correlates with visual acuity better than is true of conventional biomicroscopy. The Spearman ranks derived from the results obtained with polarised light correlate significantly with the patient's visual acuity. It is concluded that polarised light biomicroscopy, in conjunction with the standard examination, can improve the diagnosis of cataract and assist in relating it to a patient's visual acuity.

Aged↗

PubMed2006

Risk factors for ocular complications and poor visual acuity at presentation among patients with uveitis associated with juvenile idiopathic arthritis.

PURPOSE: To describe the frequencies of and risk factors for ocular complications and poor visual acuity at presentation in a cohort of patients with juvenile idiopathic arthritis (JIA)-associated uveitis. DESIGN: Cross-sectional study. METHODS: setting: Single-center, academic practice. study population: Seventy-five patients with JIA-associated uveitis were evaluated between July 1984 and August 2005. observation procedures: Data on patients diagnosed with JIA-associated uveitis were entered retrospectively into a database and analyzed. outcome measures: Visual acuity of 20/50 or worse or 20/200 or worse, and presence of ocular complications (including cataract, posterior synechiae, band keratopathy, elevated intraocular pressure, hypotony, macular edema, and epiretinal membrane) at presentation. RESULTS: At presentation, ocular complications were seen in 67% of eyes affected by JIA-associated uveitis. Presence of > or =1+ anterior chamber flare, a positive antinuclear antibody (ANA), and a shorter duration between the diagnosis of arthritis and uveitis were significantly associated with the presence of ocular complication. The frequencies of 20/50 or worse and of 20/200 or worse visual acuities at presentation in affected eyes were 36% and 24%, respectively. The presence of > or =1+ anterior chamber flare and a history of intraocular surgery before presentation were significantly associated with 20/50 or worse and 20/200 or worse vision. Presence of posterior synechiae also was associated with 20/200 or worse vision at presentation. The main causes of poor vision at presentation for affected eyes and better-seeing eyes were cataract, band keratopathy within the visual axis, and glaucoma. CONCLUSIONS: Ocular complications and poor vision at presentation were common in our patients with JIA-related uveitis.

Adolescent↗

PubMed1981

Measurement of visual acuity in latent nystagmus.

A method is described for rapid and accurate assessment of visual acuity in patients with latent (occlusion) nystagmus. By using the duochrome slide of the American Optical Project-O-Chart and the green filter of the Worth red-green glasses, monocular visual acuity may be readily measured in patients with nystagmus brought out by monocular cover. The results obtained in seven patients are compared with standard opaque occlusion and occlusion with a +5.00 diopter lens.

Humans↗