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Results for “Visual Acuity”

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PubMed1993

Visual-acuity development in healthy preterm infants: effect of marine-oil supplementation.

Docosahexaenoic acid (DHA; 22:6n-3) is important for normal visual development. We hypothesized that preterm infants fed formulas with marine oil as a source of DHA would have better visual acuity than infants fed formulas without marine oil, as measured by the Teller Acuity Card procedure. Marine oil (P < 0.001) and age (P < 0.0001) influenced visual acuity, by repeated-measures analysis of variance (ANOVA) corrected for the effect of subject. Marine-oil-supplemented infants had better visual acuity than those fed standard formulas at 2 and 4 mo of age, by Fishers' least-squares difference (LSD). Acuity of both dietary groups improved through 6.5 mo of age, then plateaued. Through 4 mo of age, acuity was inversely related to oxygen supplementation (log10 h) and positively related to DHA status, by general-linear-models (GLM) analysis. After 4 mo of age, birth weight and gestational age were the only variables consistently related to visual acuity by GLM. We conclude that marine-oil-supplemented formula improved visual acuity of preterm infants through 4 mo of age by improving DHA status.

Aging↗

PubMed1998

Visual acuity and quality of life outcomes in patients with cataract in Shunyi County, China.

PURPOSE: To measure visual acuity and vision-related quality of life in individuals in rural China operated on for cataract. METHODS: Five thousand fifty-two persons age 50 years and older, 90.9% (5,052/5,555) of a randomly selected population in Shunyi County, were examined in the fall of 1996. Visual functioning and quality of life questionnaires were administered to those with presenting visual acuity less than 6/60 in either eye and to those who were aphakic or pseudophakic. RESULTS: Of the 87 individuals operated on for cataract, 12% (10/87) had presenting visual acuity of 6/18 or more in both eyes, and 24.1% (21/87) had less than 6/60. Twenty-five percent (29/116) of the 116 eyes operated on for cataract had presenting visual acuity of 6/18 or more, and 44.8% (52/116) had less than 6/60. Aphakic cases without glasses and uncorrectable aphakia attributable to surgical complications were common. In a multivariate regression model, including time period of surgery, hospital type, and surgical procedure, only pseudophakia was associated with better outcomes (P = .05). On a scale from 0 (maximum problems) to 100 (no problems), the mean visual functioning score (+/-SD) for the operated-on population was 61.9 +/- 30.0, and 71.0 +/- 31.8 for the quality of life questionnaire. These scores were comparable to those of the unoperated-on population with moderate bilateral blindness (<6/60 to > or =3/60 in the better eye). Visual functioning and quality of life scores were closely correlated with visual acuity in operated-on (r = 0.64 and r = 0.61, respectively) and unoperated-on populations (r = 0.68 and r = 0.59, respectively). CONCLUSIONS: Both clinical and patient-reported cataract surgery outcomes are below what should be achievable. Improvement in outcomes must be given greater emphasis if the potential of cataract surgery in restoring sight is to be realized.

Aged↗

PubMedDate not supplied

Visual acuity after segmental buckling and non-drainage: a 15-year follow-up.

BACKGROUND: The question addressed is: how does the postoperative visual acuity in eyes treated with segmental buckling compare over time with the paired fellow eyes? METHODS: 107 detachments were followed prospectively for 15 years. The eyes were divided into: group I, macula attached (46); group II, macula partially detached (10); group III, macula completely detached (51). Mean preoperative visual acuity was 20/30 in group I, 20/100 in group II, and 20/400 in group III. The operation consisted of segmental buckling without drainage. No eye had cerclage or vitrectomy. RESULTS: The retina remained attached in 99 eyes during the 15-year follow-up. The mean visual acuity of all patients improved six months postoperatively to 20/40 with a maximum of 20/30 at one year. Thereafter there was a linear decrease in all three groups. CONCLUSIONS: Visual acuity improved during the first year, followed by a linear decrease of 0.07 line/year. The paired eyes decreased similarly in relation to age. There was no real difference in the visual acuity of the operated and unoperated eyes (P = 0.079) during the 15 years of follow-up. Mean visual acuity was 20/40 in the operated eyes of 72 patients who were living after 15 years. These data present a challenge to those surgeons who use techniques that include encircling the eye to review and compare their long-term visual results.

Drainage↗

PubMed1998

Visual acuity repeatability in keratoconus: impact on sample size. Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study Group.

PURPOSE: The purpose of this paper is to determine the repeatability of visual acuity measurement in keratoconus and to describe the impact of measurement repeatability on sample size. METHODS: Approximately 10% of a 1209 patient sample in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study were selected randomly for a Repeat CLEK Study Visit. Patients were tested at the 15 CLEK Participating Clinics. The test-retest sample consisted of 1 34 keratoconus patients who met the entry criteria of the CLEK Study. High and low contrast Bailey-Lovie visual acuity was measured with the patient's habitual visual correction (entrance visual acuity monocularly and binocularly), and with the best correction monocularly (either the patient's rigid contact lens and over-refraction, or with a CLEK Study trial lens and appropriate over-refraction) at two visits separated by a median of 90 days (range 22 to 268 days). RESULTS: The mean absolute differences between the number of letters correct at the two visits ranged from a low of 3.24 +/- 3.1 for entrance high contrast binocular acuity to a high of 5.48 +/- 5.1 for best corrected low contrast monocular acuity. Intraclass correlation coefficients ranged from 0.757 to 0.853. The visual acuity score was somewhat higher at the Repeat Visit than at the Baseline Visit when the examiners were different between visits. CONCLUSIONS: Given the variable vision reported by keratoconus patients, visual acuity in this sample was very repeatable. Repeatability was slightly poorer when different examiners tested visual acuity at the Baseline and Repeat Visits.

Adolescent↗

PubMed2005

[Discussion on logarithmic visual acuity chart and five grade notation].

To explore the scientific aspect of logarithmic visual acuity chart and five grade notation, a visual test-type ten times large as the test-type of 4.0 grade was put 0.5 m before the eye, if the eye saw it, then the visual acuity was 2.0 grade (visual angle 1000' = 16.67 degrees). If moving this test-type to 0.05 m before the eye, 1.0 grade (visual angle 10 000' = 166.7 degrees) was obtained. They are more scientific than original records: hand movement for 2.0 grade and light perception for 1.0 grade. These test-type theoretically satisfy the demand of 5 grade notation. Logarithmic visual acuity chart and 5 grade notation is more superior subject created in China.

Mathematics↗

PubMedDate not supplied

Visual acuity and refractive errors in the elderly in nursing homes.

A total of 268 elderly persons living in eight nursing homes in northern Finland (participation rate 100%) were examined by an ophthalmologist in 1980-1983 in order to describe visual acuity and the occurrence of refractive errors. Uncorrected distant visual acuity in the better eye was less than 0.4 in 76% of the men and 68% of the women, being worse in older subjects than in younger ones. Uncorrected near visual acuity in the better eye was less than 0.1 in 24% of the men and 25% of the women. Hyperopia was found in 78% of the men and 77-78% of the women and myopia in 14-15% of the men and 15-16% of the women. Hyperopia decreased and myopia increased with age. Astigmatism was uncommon and its prevalence figure was not related to sex or age. Only 3% of men and 5% of women were emmetropic. We may conclude that uncorrected distant visual acuity of the population was low, and three out of every four men and two out of every three women were unable to manage their daily activities without difficulties due to the low visual acuity. Also uncorrected near visual acuity was low, and one out of every four persons was practically blind.

Aged↗

PubMed2006

Implantable miniature telescope for the treatment of visual acuity loss resulting from end-stage age-related macular degeneration: 1-year results.

PURPOSE: To evaluate the safety and efficacy of an implantable visual prosthetic device (IMT; VisionCare Ophthalmic Technologies, Saratoga, CA) in patients with bilateral, end-stage age-related macular degeneration (AMD). DESIGN: Prospective, open-label, multicenter clinical trial with fellow eye controls. PARTICIPANTS: A total of 217 patients (mean age, 76 years) with AMD and moderate to profound bilateral central visual acuity loss (20/80-20/800) resulting from bilateral untreatable geographic atrophy, disciform scars, or both were enrolled. METHODS: A visual prosthetic device (implantable telescope), designed to enlarge retinal images of the central visual field, was implanted monocularly in the capsular bag after lens extraction. Fellow eyes were not implanted to provide peripheral vision and served as controls. Study patients participated in 6 visual rehabilitation visits after surgery. MAIN OUTCOME MEASURES: Best-corrected distance visual acuity (BCDVA) and best-corrected near visual acuity (BCNVA), quality-of-life scores from the National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ-25) and the Activities of Daily Life scale, endothelial cell density (ECD), and incidence of complications and adverse events. RESULTS: At 1 year, 67% of implanted eyes achieved a 3-line or more improvement in BCDVA versus 13% of fellow eye controls (P<0.0001). Fifty-three percent of implanted eyes achieved a 3-line or more improvement in both BCDVA and BCNVA versus 10% of fellow eyes (P<0.0001). Mean BCDVA and BCNVA improved 3.5 lines and 3.2 lines, respectively, in implanted eyes versus 0.8 lines and 1.8 lines, respectively, in fellow eyes (P<0.0001). Change in visual acuity was not related to lesion type. Mean NEI VFQ-25 scores improved by more than 7 points from baseline (P<0.01) on 7 of 8 relevant subscales. Eleven eyes did not receive the device because of an aborted procedure. Endothelial cell density was reduced by 20% at 3 months and 25% at 1 year. The decrease in ECD was correlated with postsurgical edema (P<0.0001), and there was no evidence that endothelial cell loss is accelerated by ongoing endothelial trauma after implantation. CONCLUSIONS: This implantable visual prosthesis can improve visual acuity and quality of life in patients with moderate to profound visual impairment caused by bilateral, end-stage AMD.

Activities of Daily Living↗

PubMed1981

Development of visual acuity in infants with congenital cataracts.

The visual acuity of 4 infants with congenital cataracts was measured serially during the first year of life by a preferential looking technique. Two infants with bilateral cataracts and no measurable acuity before surgery showed rapid development of acuity to normal levels for age after surgery and optical correction. In an infant with a unilateral cataract and an infant with a cataract and persistent hyperplastic primary vitreous marked differences in monocular acuities were found after surgery. Acuities became equal in the latter case after occlusion of the normal eye, while the other infant recovered acuity with 'bi-ocular' viewing. These acuity measurements demonstrate the sensitivity of the human visual system to binocular and monouclar visual form deprivation in the first year of life.

Cataract↗

PubMed1978

[The importance of the interference fringe visual acuity in the indication of a cataract-extraction (author's transl)].

100 patients have been examined before and after cataract-extraction using the Retinal Visual Acuity Tester, Takata, Japan. Laser produced interference fringes are formed on the retina, as a result the visual acuity can be determined easily before the operation. -- With immature cataracts we obtained a good correlation between the preoperative interference fringe visual acuity and the postoperative visual acuity tested by Landoltrings. Therefore, it can be differentiated whether worse visual acuity is caused by the cataract or by a retinal disease.

Adult↗

PubMedDate not supplied

Visual acuity and corneal topographic changes related with pterygium surgery.

PURPOSE: Applied pre- and postoperative corneal topography outcomes with visual acuities were evaluated to determine the surgical results in pterygium therapy. METHODS: The study group consisted of 30 eyes of 26 patients with primary and recurrent pterygium. Mean patient age was 52.26+/-11.50 years (range: 27 to 68 years). Pre- and postoperative visual acuity and comeal topography were evaluated for each case. Statistical analysis was performed using the repeated-measure test. RESULTS: The mean uncorrected visual acuity was 0.41+/-0.30 preoperatively and 0.63+/-0.26 postoperatively (P<.001). The mean best spectacle-corrected visual acuity was 0.59+/-0.28 preoperatively and 0.84+/-0.22 postoperatively (P<.001). Surface regularity index ranged from 1.96+/-1.08 preoperatively to 1.09+/-0.76 postoperatively (P<.001). The mean surface asymmetry index was 3.05+/-2.85 preoperatively and 1.39+/-1.70 postoperatively (P=.003). The mean topographic astigmatism was 4.65+/-3.02 preoperatively and 2.33+/-2.26 postoperatively (P=.003). CONCLUSIONS: Examination of the topographic records reveals pterygium-associated corneal flattening in the horizontal meridian along the line of the pterygium. The improvement in topographic pattern and best spectacle-corrected visual acuity can be used as one indicator of the success of pterygium surgery.

Adolescent↗

PubMed1983

Evoked potential and preferential looking estimates of visual acuity in pediatric patients.

Pattern visual evoked potentials (VEPs) and behavioral visual acuity measured with forced-choice preferential looking techniques (FPL) were obtained from 172 pediatric patients between the ages of 4 months and 10 years. More children younger than 2 years of age successfully completed monocular testing by pattern VEP than by FPL methods. For children older than 2 years, we were equally successful in completing each of the two tests. Of those children who completed both tests, the VEP results agreed with Snellen, Allen, and "E" acuity measures more often (66%) than did the FPL results (50%). Both tests were more sensitive than Allen single characters in detecting interocular acuity differences in children younger than 3 years of age.

Age Factors↗

PubMed1995

The influence of treatment extent on the visual acuity of eyes treated with Krypton laser for juxtafoveal choroidal neovascularization. Macular Photocoagulation Study Group.

PURPOSE: To examine the direct relationship between the extent of treatment with krypton red laser photocoagulation and visual acuity loss in eyes with choroidal neovascularization secondary to ocular histoplasmosis or age-related macular degeneration. PATIENTS AND METHODS: Photographic and visual acuity records from 129 eyes treated in the Ocular Histoplasmosis Study--Krypton Laser and 224 eyes treated in the Age-Related Macular Degeneration Study--Krypton Laser were reviewed. The proportion of eyes with severe visual acuity loss (6 or more lines of loss) was examined for subgroups of eyes based on the distance of the neovascular lesion from the center of the foveal avascular zone and on the extent of laser treatment to the lesion. Differences in the proportions with severe visual acuity loss were evaluated by longitudinal data analysis methods. RESULTS: Among eyes in the Ocular Histoplasmosis Study--Krypton Laser with lesions less than 200 microns from the center of the foveal avascular zone, only 5% of eyes with laser treatment that covered the foveal side and had a narrow (< or = 100 microns) border of treatment to adjacent uninvolved retina experienced severe visual acuity loss compared with approximately 25% of eyes with either some of the foveal side of the lesion left untreated or a wide border of treatment on the foveal side. Treatment extent had little influence on severe visual acuity loss in eyes in the Ocular Histoplasmosis Study--Krypton Laser with neovascular lesions 200 to 500 microns from the center of the foveal avascular zone or in eyes in the Age-Related Macular Degeneration Study--Krypton Laser with lesions in either distance category. CONCLUSIONS: Accurate, complete treatment of choroidal neovascularization close to the foveal center is required to provide the patient with the best chance of avoiding further severe visual acuity loss, especially in patients with ocular histoplasmosis. Even among experienced retinal specialists, the required accuracy of treatment is difficult to achieve.

Adolescent↗

PubMed1991

[Relation of visual acuity of test field luminance in glare sensitivity of various origin].

Intolerance to bright light is a nonspecific ophthalmological symptom, originating either in disturbances of the optic apparatus of the eye or caused by functional disturbances of the neuronal network of the retina. Disturbances in brightness and darkness adaptation can often cause considerable decrease in visual acuity, which is not evident in the standardized tests that measure photophobia in conjunction with visual function. If the test field is very bright and the patient has photophobia, the visual acuity is often reduced considerably. The relationship between visual acuity and luminance of the test field was determined in glare--sensitive patients using a relatively simple method and a large range of luminances (0.1-30,000 cd/m2). In contrast to previously used methods, visual acuity was determined in a range where neuronal mechanism can be expected to be responsible for adaptation to brightness. We found disturbances in the relationship between visual acuity and luminance in several diseases, and it was especially pronounced in cone dystrophies. Affections of the optic nerve and opacities of the optic media usually did not cause a marked decrease in visual acuity at high luminances. As a supplemental investigation to mesoptometry and nyctometry, the method described here primarily permits types of photophobia to be determined that are not caused by stray light. The dynamic nature of neuronal adaptation processes determined by this test has therefore considerable influence on visual acuity.

Adaptation, Ocular↗

PubMed2001

The amblyopia treatment study visual acuity testing protocol.

OBJECTIVE: To evaluate the reliability of a new visual acuity testing protocol for children using isolated surrounded HOTV optotypes. METHODS: After initial pilot testing and modification, the protocol was evaluated using the Baylor-Video Acuity Tester (BVAT) to present isolated surrounded HOTV optotypes. At 6 sites, the protocol was evaluated for testability in 178 children aged 2 to 7 years and for reliability in a subset of 88 children. Twenty-eight percent of the 178 children were classified as having amblyopia. RESULTS: Using the modified protocol, testability ranged from 24% in 2-year-olds to 96% in 5- to 7-year-olds. Test-retest reliability was high (r = 0.82), with 93% of retest scores within 0.1 logMAR unit of the initial test score. The 95% confidence interval for an acuity score was calculated to be the score +/-0.125 logMAR unit. For a change between 2 acuity scores, the 95% confidence interval was the difference +/-0.18 logMAR unit. CONCLUSIONS: The visual acuity protocol had a high level of testability in 3- to 7-year-olds and excellent test-retest reliability. The protocol has been incorporated into the multicenter Amblyopia Treatment Study and has wide potential application for standardizing visual acuity testing in children.

Amblyopia↗

PubMed1987

[Determination of visual acuity using optokinetic nystagmus. A newly developed instrument based on Günther's principle].

The two most important methods used for objective determination of visual acuity are those of Ohm-von Romberg and Günther. A newly developed instrument based on Günther's principle is described which combines the advantages of both methods. Using a Leitz projector and a specially designed accessory unit, a constantly moving screen of dots measuring 64 X 64 cm is projected. The setting was standardized on the basis of 358 eyes with visual acuities ranging from finger counting to 1.0. The correlation between the measured distance (from screen to patient) at which an optokinetic nystagmus was just induced and visual acuity was r = 0.98 over the entire visual acuity range. The visual acuity to be expected can be read off from the diagrams or a table, with a scatter range of +/- 1 sigma, +/- 2 sigma, or +/- 3 sigma. The relevant literature is discussed. Replication of the accessory unit described can be recommended.

Humans↗

PubMed1989

Reversible changes of visual acuity and pattern-electroretinograms after blue-green argon laser photocoagulation of diabetic patients.

Visual acuity, color vision, pattern-visual-evoked-potentials (P-VEPs) and pattern-electroretinograms (P-ERGs) were measured in 13 diabetic subjects before, and 24 hours and 5 weeks after blue-green argon laser treatment. As control, the same examinations were performed in 7 normal subjects and 7 diabetic patients before and after slit lamp examination with the Goldman three mirror contact lens. Visual acuity and P-ERG amplitudes were significantly reduced one day after the laser treatment, while 5 weeks after the laser coagulation, visual acuity and P-ERG amplitudes recovered to pretreatment values. The control group showed no significant changes after slit lamp examination. Since fluorescein angiography revealed no macular changes after laser treatment, the possibility of a reversible functional light damage after blue-green argon laser coagulation (ALC) is discussed.

Aged↗

PubMed2002

Factors associated with reduced visual acuity during long-term follow-up of patients with idiopathic central serous chorioretinopathy.

PURPOSE: To investigate factors associated with reduced visual acuity during long-term follow-up of patients with idiopathic central serous chorioretinopathy (ICSC). METHODS: Retrospective consecutive case series that included patients with ICSC who were younger than 50 years of age at the time of initial examination and were followed up for > or =3 years. RESULTS: The mean follow-up for 101 involved eyes of 61 patients was 9.8 years (median, 8.0 years). Eyes were stratified into two groups based on visual acuity at the final examination: Group 1, visual acuity of 2040 or better; and Group 2, visual acuity of worse than 2040. Findings identified as potential risk factors for reduced vision at the final follow-up examinations for Group 1 versus Group 2 included the following: macular retinal pigment epithelium atrophy (90.8% versus 96.0%, respectively; P = 0.68); persistent pigment epithelial detachment or persistent subretinal fluid (5.3% versus 28.0%, respectively; P = 0.004); recurrences (39.5% versus 68.0%, respectively; P = 0.020); laser treatment (28.9% versus 32.0%, respectively; P = 0.80); and submacular choroidal neovascularization (0.0 versus 8.0%, respectively; P = 0.059). CONCLUSIONS: Factors associated with reduced visual acuity during long-term follow-up of patients with ICSC included persistent pigment epithelial detachment and/or subretinal fluid, recurrences, and submacular choroidal neovascularization.

Adult↗

PubMed1994

Visual acuity measurement in exceptional children.

BACKGROUND: Numerous reports have been published describing the determination of visual acuity in infants using forced-choice preferential-looking (FPL) methods. Results confirm the effectiveness of this technique for evaluating the child who is unable to respond to conventional clinical methods of visual acuity measurement (e.g., Snellen Letter or Symbol Acuity). METHODS: Using a FPL acuity apparatus and discrimination paradigm similar to that developed and modified by Held, Gwiazda, Mohindra et al., and also used by Atkinson et al., we used grating acuity assessment with binomial method of rapid endpoint determination as well as luminance matched targets (+/- 3.4 percent) with grating regularity controlled (+/- 2.35 percent) in studies of 105 full-term infants with normally developing vision and six exceptional children. CONCLUSIONS: The results of these investigations show that monocular grating acuity thresholds measured in infants in a clinically useful way were also measurable in exceptional children when conventional visual acuity testing failed, thereby enabling the monitoring of improvements in visual acuity and performance for five of the six exceptional children studied.

Adolescent↗