SEARCH · PubMed Health

Results for “Visual Acuity”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 811 records · Page 45Linked to original sources

PubMed1994

Twenty-four-month follow-up of excimer laser photorefractive keratectomy for myopia. Refractive and visual acuity results.

PURPOSE: To evaluate the 24-month refractive outcome of excimer laser photorefractive keratectomy (PRK) performed on normal, sighted myopic eyes; and to assess the evolution of postoperative refraction, the accuracy of predicted correction, and the results in terms of uncorrected visual acuity. METHODS: Photorefractive keratectomy was performed on 495 eyes, with a preoperative refraction ranging from -1.25 to -7.50 diopters (D). Ablation zone diameters of 4.3 and 4.5 mm were used. All patients were treated with a standard topical steroid regimen postoperatively. Minimum follow-up time was 24 months. RESULTS: Mean refraction (spherical equivalent +/- standard deviation) at 24 months was -0.27 +/- 0.74 D, which was significantly (P < 0.01) different from the mean at 12 months (0.01 +/- 0.78 D). There was also a significant (P = 0.01) difference between the 12- and 18-month (-0.15 +/- 0.82 D) mean refractions. But there was no significant difference between the means at 18 and 24 months postoperatively. Subgroup analysis at 24 months showed that patients with low to moderate myopia (up to -3.90 D) had significantly better refractive outcomes than those with higher myopia. Also at 24 months, 91% of the eyes had an uncorrected visual acuity of at least 20/40, and 81.5% had an uncorrected visual acuity of at least 20/30. Correspondingly, 87.5% of the eyes were within 1.00 D of emmetropia, and 71.7% were within 0.50 D. Only 0.4% lost one line of best-corrected visual acuity, no eye lost two lines or more. CONCLUSIONS: Refraction after PRK is slow to stabilize, but appears to reach stability by 18 to 24 months after surgery. The refractive results are reasonably predictable and compare well with those achieved with radial keratotomy.

Adult↗

PubMed1996

Lens induced glaucomas--visual results and risk factors for final visual acuity.

Lens induced glaucomas are a common occurrence in India. An attempt was made to understand the clinical modes of presentation and post operative visual results in 93 patients with lens induced glaucoma, 49 phacomorphic and 44 phacolytic, attending our institute during 1994. All these patients were subjected to a planned extracapsular cataract extraction. Forty four percent had a posterior chamber intraocular lens implantation following surgery. Fifty seven percent eyes with phacomorphic glaucoma and 61% with phacolytic glaucoma recovered visual acuity of 6/12 or better. There was no significant difference in the final visual acuity between those patients who had an intraocular lens implanted and those who did not (P = 0.18). Univariate analysis was performed for selected risk factors such as age, sex and duration of glaucomatous process as predictors of final visual acuity and odds ratios with 95% confidence intervals were calculated. Patients with age more than 60 years (OR = 2.7, 95% CI = 1.04-6.93) and in whom the glaucoma was present for more than 5 days (OR = 3.1, 95% CI = 1.21-8.13) had a significantly higher risk of poor visual outcome post-operatively.

Adult↗

PubMed1992

Measurement of potential visual acuity in 343 patients with cataracts. A prospective clinical study.

In 343 patients with cataracts (the largest consecutive series in which this subject has been addressed) and 63 patients with clear optic media, who served as the control group, potential visual acuity was measured with the Guyton/Minkowski Potential Acuity Meter (PAM). The control group included 32 cases of macular degeneration, 22 cases of glaucoma, and 9 cases of amblyopia. The cataract group comprised 46 patients with macular degeneration, 46 with glaucoma, and 8 with amblyopia; 5-7 days postoperatively, corrected visual acuity was measured in this group. Because of dense cataracts in 59 patients, no PAM value could be obtained. The visual acuity of 70.4% of the patients, in whom complete data were obtained, was within one Snellen line of the predicted value or better (21%). In general, postoperative predictions were accurate in patients with moderate cataracts. The results were not affected by glaucoma or amblyopia. In 17.5% of patients with macular degeneration, false-positive results were obtained. The control group, in which distance visual acuity was compared with the PAM values, rendered comparable results, with 86.9% of the PAM predictions being correct.

Adult↗

PubMed1986

Comparability of ophthalmic diagnoses by clinical and Reading Center examiners in the Visual Acuity Impairment Survey Pilot Study.

Technologic advances in ophthalmic equipment offer the possibility of replacing direct clinical examinations with Reading Center evaluations of data recorded in epidemiologic studies. Clinical and Reading Center examiners made independent ophthalmic diagnoses of 133 right and 132 left eyes of 138 adults in the Visual Acuity Impairment Survey Pilot Study, carried out in three US cities, Boston, Detroit, and Minneapolis, in August 1981-December 1982. The Reading Center diagnosed eye conditions using only photographic and visual field data collected at the time of the clinical examination. In the comparisons of clinical and Reading Center evaluations reported here, only eyes judged by the examiners to have pathology severe enough to reduce visual acuity to 6/9 or worse were classified as having pathology. (No visual acuity criterion was required for the diagnosis of glaucoma or diabetic retinopathy.) There was agreement in diagnostic assessments between clinical and Reading Center examiners in about 80% of eyes. The kappa statistic, which adjusts for chance agreement, was in the fair to good range: 0.60 for 133 right eyes and 0.62 for 132 left eyes. When the Reading Center examiners were provided with additional information on medical history, refractive error and best corrected visual acuity, the agreement between clinical and Reading Center assessments among the subset of eyes with 6/9 or worse vision again was in the fair to good range, with kappas of 0.61 for 45 right eyes and 0.68 for 48 left eyes. Inter-observer agreement between Reading Center examiners in diagnosing pathology was in the good to excellent range. Use of Reading Centers in future epidemiologic studies should be considered, but elimination of the clinical examinations is not recommended until modifications in the protocol described here have been made and shown to improve levels of agreement between clinical and Reading Center examiners.

Eye Diseases↗

PubMed1999

The decrease of visual acuity in cataract patients waiting for surgery.

PURPOSE: To investigate the rapidity of vision loss in eyes waiting for cataract surgery and to estimate what proportion of life expectancy the extended wait for surgery comprised. METHODS: The visual acuities at the time of referral and on the day before surgery were compared in 124 patients operated on for cataract in the Vaasa Central Hospital, Finland. The expected survival of the patients after surgery was calculated individually using the Finnish life statistics. RESULTS: During the waiting time of 13 months on the average, the visual acuity in the study eye decreased from 0.68 logMAR (0.2 in decimal values) to 0.96 logMAR (0.1). The average decrease in vision was 0.27 logMAR per year varying from none to 2.07 logMAR units. 30% of the eyes experienced worsening of vision by 60% or more while 48% had no or minimal worsening (<0.2 logMAR). The rapidity of change in visual acuity was somewhat less in older patients (75 years or older), but the difference was not statistically significant. The percentage of persons with visual acuity of 0.5 or better in the better eye decreased from 66% to 41% and those with low vision (<0.3 in the better eye) increased from 8% to 21%. The mean waiting time in relation to the expected survival for all patients was 13% varying from less than 5% in 10 patients to more than 25% in 8 patients. CONCLUSION: Progression of vision loss in eyes waiting for cataract surgery varies significantly. For many patients the extended delay caused remarkable disability for a considerable part of their remaining lifetime.

Aged↗

PubMed1981

[Relation of color-coordinate transposition in temporal papillary pallor to visual acuity].

The authors first described the method of fundus color measurement by visual comparison in 1974, and by its use the clinician is able to follow the development of optic disc atrophy or diseases in which hyperemia is seen by using quantitatively defined color coordinates. Color coordinates of the nasal and temporal papillary halves in 100 normal eyes are demonstrated in the x and y plane. The palor range in atrophy is in the upper left part of the scale in comparison to normality. The mathematical relationship between visual acuity and temporal papillary palor is demonstrated in a defined group of 98 eyes. A formula has been derived with which the probable visual acuity can be calculated from the measured color coordinates and its clinical use is described.

Color↗

PubMed1998

Good visual acuity in an adult population with marked posterior segment changes secondary to retinopathy of prematurity.

PURPOSE: To show that good visual acuity can be compatible with marked posterior segment changes secondary to retinopathy of prematurity (ROP) in the adult population. METHODS: A retrospective chart review of adult patients with regressed ROP. We found 14 eyes in 12 patients who were older than 21 years with a visual acuity of 20/60 or better associated with marked posterior segment changes secondary to ROP. RESULTS: Of the 14 eyes, 11 were myopic, with six eyes having the spherical equivalent of > or = -6.00. Best-corrected visual acuities ranged from 20/15-20/60. One eye had a macular fold. Thirteen eyes had macular ectopia. CONCLUSIONS: Good vision can be compatible with marked posterior segment changes secondary to ROP in an adult population. This emphasizes the need to follow these patients closely during childhood and treat them promptly for any amblyogenic condition that could prevent them from reaching their full visual potential.

Adult↗

PubMed2004

Are routine preoperative medical tests needed with cataract surgery? Study of visual acuity outcome.

PURPOSE: The aim of this prospective randomized clinical trial was to investigate whether routine medical testing before cataract surgery reduced the rate of ocular surgical complications and to study its impact on visual acuity outcome. METHODS: The study was carried out in an academic medical center in Brazil, at State University of Campinas, between 10 February 2000 and 10 January 2001. The scheduled cataract operations were randomly assigned to one of two groups: 1) to be preceded by routine medical testing (the "routine-testing group") or 2) not to be preceded by routine medical testing (the "selective-testing group"). If the patient was assigned to the selective-testing group, it was requested that no preoperative testing be performed unless the patient presented with a new or worsening medical problem that would warrant medical evaluation with testing. In the case of patients assigned to the routine-testing group, three tests were requested: a 12-lead electrocardiogram, a complete blood count, and measurements of serum glucose. Ocular surgical complications, preoperative and postoperative best-corrected visual acuity were recorded on a standardized form. RESULTS: The sample of 1025 patients scheduled to undergo cataract surgery was comprised of 512 assigned to the routine-testing group and of 513 assigned to the selective-testing group. The two groups had similar proportions of operations canceled and not subsequently rescheduled, 2% in each group. The cumulative rate of ocular surgical complications was similar in the two groups, 20.5% in the routine-testing group and 19.3% in the selective-testing group (p = 0.624). The preoperative and the postoperative best-corrected visual acuity were similar in both groups (p = 0.999 in the former and p = 0.664 in the latter). CONCLUSIONS: The results of this study suggest that routine medical testing before cataract surgery did not reduce the rate of ocular surgical complications and did not influence visual acuity outcome.

Academic Medical Centers↗

PubMed1997

Visual vestibular interaction in the dynamic visual acuity test during voluntary head rotation.

BACKGROUND: Although intact vestibular function is indispensable to maintaining spatial orientation, no good screening tests of vestibular function are implemented in the aviation community. High frequency voluntary head rotation was selected as a vestibular stimulus to isolate the vestibulo-ocular reflex (VOR) from visual influence. METHOD: A dynamic visual acuity test that incorporates voluntary head rotation was evaluated as a potential vestibular function screening tool: 27 normal subjects performed voluntary sinusoidal head rotation at frequencies from 0.7-4 Hz under 3 different visual conditions: visually-enhanced VOR, normal VOR, and visually suppressed VOR. Standardized Bailey-Lovie chart letters were presented on a computer monitor in front of the subject, who then was asked to read the letters while rotating his head horizontally. The electro-oculogram and dynamic visual acuity score were recorded and analyzed. RESULTS: There was no significant difference in gain or phase shift among 3 visual conditions in the frequency range 2.8-4 Hz. The dynamic visual acuity score shifted less than 0.3 log MAR at frequencies under 2.0 Hz. CONCLUSION: The dynamic visual acuity test at frequencies around 2 Hz can be recommended for evaluating vestibular function.

Adult↗

PubMed2001

Changes in visual acuity in a population over a 10-year period : The Beaver Dam Eye Study.

PURPOSE: To describe the change in visual acuity in a 10-year period. DESIGN: Population-based cohort study. PARTICIPANTS: Included 3684 persons 43 to 86 years of age at the time of a baseline examination in 1988 to 1990, living in Beaver Dam, Wisconsin, at a follow-up examination in 1993 to 1995 and/or 1998 to 2000. METHODS: Best-corrected visual acuity was measured, after refraction, with logarithm of the minimum angle of resolution charts using a modification of the Early Treatment Diabetic Retinopathy Study protocol. MAIN OUTCOMES MEASURES: Doubling of the visual angle and incidence of visual impairment. RESULTS: The change in the mean number of letters read correctly over the 10-year period varied in the right eye from -0.9 (standard deviation [SD] = 5.5) and in the left eye from -1.2 (SD = 6.6) in people between 43 and 54 years of age to -11.0 (SD = 20.0) in the right eye and -12.6 (SD = 20.4) in the left eye in people 75 years of age or older (n = 184) at baseline. Over the 10-year period, 5.9% of the population had impaired vision (20/40 or worse in the better eye) develop, 0.8% had severe visual impairment (20/200 or worse in the better eye) develop, 4.8% had doubling of the visual angle, and 3.9% had improved vision. People who were 75 years of age or older at baseline were 15.0 times (95% confidence interval [CI], 10.9-20.6; P < 0.001) as likely to have impaired vision develop, 9.3 times (95% CI, 6.5-13.3; P < 0.001) as likely to have doubling of the visual angle, and 19.8 times as likely (95% CI, 8.4-46.4; P < or = 0.001) to have severe visual impairment develop than people younger than 75 years of age at baseline. For the 82 persons 75 years of age or older, currently residing in a nursing or group home at follow-up, they were 2.6 times (95% CI, 1.45-4.52) as likely to have impaired vision develop, 1.6 times (95% CI, 0.47-5.62) as likely to have severely impaired vision develop, and 3.6 times (95% CI, 1.96-6.78) as likely to have had a doubling of the visual angle than those not residing in a nursing or group home at follow-up. CONCLUSIONS: These data provide precise population-based estimates of the 10-year incidence of loss of vision over a wide spectrum of ages and show that decreased visual acuity in people 75 years of age after 10 years is a common finding, especially in those who are admitted to nursing or group homes.

Adult↗

PubMedDate not supplied

Self-reported acute decrease in visual acuity after photodynamic therapy for age-related macular degeneration.

PURPOSE: To evaluate the incidence of self-reported decrease in visual acuity within 7 days of photodynamic therapy (PDT) for choroidal neovascularization secondary to age-related macular degeneration (AMD) and to describe the anatomical and clinical course of patients with documented significant visual loss. METHODS: Consecutive records of all patients with exudative AMD treated with PDT over a 16-month period at a community-based retina referral practice were reviewed for instances of self-reported visual change within 7 days of treatment. The primary outcome measure was Snellen visual acuity. Secondary outcome measures were fluorescein angiography (FA) and anatomical findings. RESULTS: Among 1,894 PDT treatments performed for 821 patients, there were 32 instances (for 30 patients) of self-reported visual change within 7 days of PDT. A decrease in > or =2 lines of Snellen visual acuity was documented for 10 patients (1.2% of patients or 0.5% of treatments), and all occurred within 3 days of PDT (median, 1 day) in all patients. Median pre-PDT vision was 20/60 (range, 20/50 to 20/200). Vision within 3 days after PDT was 20/100 or worse in all 10 cases and counting fingers or worse in 3. Subretinal hemorrhage occurred in four cases. FA of eyes without hemorrhage showed a circular area of choroidal hypoperfusion (corresponding to the PDT spot) in all five eyes with persistence of the hypofluorescence up to 4 months later. Visual improvement after the initial acute decrease was seen in 3 patients (30%; 95% confidence interval, 7-65%) by 3 months after PDT. CONCLUSIONS: Acute visual decrease after PDT for AMD is uncommon. Visual recovery may occur in some patients, but a precise estimate is difficult to determine given the small sample size.

Acute Disease↗

PubMed1994

Effect of a low dose of alcohol on dynamic visual acuity.

An experiment was carried out to investigate the relationship between dynamic visual acuity and a low dose of alcohol. For the study, 18 subjects ranging from 18 to 25 years of age were chosen. The subjects' dynamic visual acuities were compared before and after drinking 16.5 ml of alcohol, the amount in one standard can of beer. It was found that the acuity improved 30 min. after consuming this low volume of alcohol.

Adolescent↗

PubMed1993

On the statistical reliability of letter-chart visual acuity measurements.

PURPOSE: To determine boundary values of test-retest reliability and sensitivity to acuity change that are unlikely to be exceeded in any clinical situation, for a popular visual acuity chart (Lighthouse/ETDRS) with three scoring methods; to discuss general methodological issues associated with statistical accuracy of optotype chart testing; and to link measures of test reliability to measures of sensitivity to change. METHODS: Five highly practiced subjects were tested using a computer-controlled acuity testing system in a procedure designed to reduce measurement error. Subjects read the computerized chart 156 times, yielding a sample of 78 test-retest comparisons. RESULTS: Under conditions likely to minimize variability, visual acuity may, with 95% confidence, be ascertained only within +/- 0.1 log units, using this chart with the recommended letter-by-letter scoring. Detecting a significant change in visual acuity requires about +/- 0.14 log units for the same degree of confidence. CONCLUSIONS: These measurements may be viewed as approaching the upper limit of reliability of this letter chart. Reliability probably is considerably less in typical usage.

Humans↗

PubMed2001

[Nd YAG laser microsurgery for pupil centering and improvement of visual acuity].

PURPOSE: To define the use of Nd YAG laser treatment for centering the pupil--coreoplasty and improvement of the visual acuity. MATERIAL AND METHODS: We used Nd YAG laser for coreoplasty in 29 eye of the patient, aged between 6 and 90. The eyes were classified in four groups using the disposition of the pupil according to the optic axis criteria. We used our own methods for centering the pupil. The average power was 3 +/- 0.2 mj, and the average number of applications--5 +/- 2. RESULTS: The Nd YAG laser coreoplasty succeeded in all 29 eyes. In 96.55% of the eyes the visual acuity was very good and excellent. CONCLUSION: The dislocation of the pupil according to the optic axis due to trauma or surgery complication always decreases the function of the damaged eye. The Nd YAG laser helps to improve the visual acuity--an excellent effect, produced in several minutes in dispensary conditions.

Adolescent↗

PubMed2006

Visual acuity in children with glaucoma.

PURPOSE: To investigate the risk factors that influence outcome of visual function in children with glaucoma. DESIGN: Retrospective noncomparative interventional case series. PARTICIPANTS: One hundred twenty-six patients (204 eyes) who had childhood glaucoma observed over 30 years, with a mean follow-up of 11.6 years. INTERVENTIONS: Full ophthalmologic examination, including measurement of corrected visual acuity (VA), slit-lamp and fundus examinations, intraocular pressure (IOP) measurement, and gonioscopic evaluation; periodic cycloplegic refraction and perimetry; and treatment of amblyopia. MAIN OUTCOME MEASURES: Type of glaucoma; final best-corrected VA of good (6/6-6/12), fair (6/15-6/30), or poor (< or =6/60); patient age at time of development of glaucoma complications; and percentage of IOP measurements of < or =19 mmHg, perimetry results, and cup-to-disc (C/D) ratio during follow-up. RESULTS: The most recently measured VAs of children treated for glaucoma were good in 29%, fair in 24%, and poor in 47%. The most favorable outcome was for patients with primary infantile glaucoma followed by secondary glaucoma. Amblyopia and optic nerve damage due to glaucoma were the most frequent complications affecting VA. Patients with an IOP of < or =19 mmHg on 80% of determinations had stable optic nerve C/D ratios and visual fields. CONCLUSIONS: Vision sufficient to qualify for a motor vehicle driving license was attainable in almost 30% of affected eyes. Visual acuity achieved at 6 years of age remained stable over the study period. Treatment of amblyopia is important to achieve this result.

Adolescent↗

PubMed1994

Risk of accidents among elderly car drivers with visual acuity equal to 6/12 or 6/15 and lack of binocular vision.

To document the risk of road accidents associated with minimal visual acuity (equal to 6/12 or 6/15) and lack of binocularity (stereoacuity > or = 200 sec arc), 1400 drivers who had had an accident during their 70th year were compared with 2636 controls randomly selected from the 30,000 70-year-old drivers who had had no accident during the same time. Information on visual characteristics and demerit points was obtained for all subjects from the Quebec Automobile Insurance Board. Mileage and prevailing driving conditions were documented through a mail questionnaire. The relative risks of accidents were estimated while controlling for traffic convictions, mileage, time spent and frequency of driving during rush hours. Drivers with minimal visual acuity alone had the same risk of road accidents as other drivers (OR = 0.97 CI 95%: 0.68-1.38). The risk of accidents among drivers with both minimal visual acuity and lack of binocularity was moderately higher than among other drivers (OR = 1.23, CI 95%: 0.88-1.72).

Accidents, Traffic↗

PubMed2001

Octreotide reduces vitreous hemorrhage and loss of visual acuity risk in patients with high-risk proliferative diabetic retinopathy.

OBJECTIVE: Growth hormone and insulin-like growth factor-I have been implicated as strong promoters of proliferative diabetic retinopathy. We studied reduction of bleeding and preservation of visual acuity by treatment with the long-acting somatostatin analogue, octreotide, in diabetic patients at an advanced stage of proliferative diabetic retinopathy. RESEARCH DESIGN AND METHODS: Randomized trial in a University hospital setting. Reading ophthalmologists were masked for octreotide use, diabetologists were aware of that treatment. Nine patients received 100 microg tid octreotide (verum) subcutaneously for a maximum of 36 months. Nine diabetics served as controls, no placebo treatment was used. Episodes of vitreous hemorrhages were counted, measurement of visual acuity, estimation of neovascularization by stereoscopic fundus photography and fluorescein angiography were carried out. RESULTS: After 3 years of treatment, the incidence of vitreous hemorrhages and the need for vitreoretinal surgery was significantly lower (log rank test p = 0.002) in the octreotide-treated patients. Visual acuity was preserved and significantly better in the octreotide treated group compared to controls (p = 0.05). CONCLUSIONS: In diabetics with high-risk proliferative retinopathy after full scatter laser coagulation, octreotide reduced the number of vitreous hemorrhages, preserving visual acuity.

Adult↗

PubMed1995

Measurement of visual acuity with two different charts; a comparison of results and repeatability in patients with cataract.

PURPOSE: To compare two different optotypes to measure visual acuity. METHODS: Experiment 1: Fifty patients with moderate cataracts were asked to read a chart consisting of letters of the alphabet (Sloan letters) first and a chart comprising Landolt's broken rings afterwards. Experiment 2: Half of patients were instructed to repeat the reading with a second letter chart, the other half was instructed to read the chart with the broken rings again. RESULTS AND CONCLUSIONS: Experiment 1: It was found that with the letter chart more optotypes (two to four) were recognized than with the broken ring chart. The different result of visual acuity measurement with the two optotypes is irrespective of the visual acuity. Experiment 2: The re-read instruction revealed that the measurements were reproduced equally for both charts.

Cataract↗