Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Visual Acuity”

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

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

At least 145 records · Page 8Linked to original sources
PubMed1990

Visual acuity loss in retinitis pigmentosa. Relationship to visual field loss.

We compared visual acuity with visual field radius in 235 patients with typical retinitis pigmentosa and no evidence of other visual acuity-limiting problems (such as cataract or foveal cystoid edema). Results show a strong relationship between visual acuity loss and proximity to the fovea of the visual field border (shortest distance from the foveal center to the border of the V-4-e isopter) for these patients. Ninety-six percent of patients with central visual field radii greater than 30 degrees have visual acuities of 20/40 or better; 32% of patients with central visual field radii smaller than 10 degrees have visual acuity of 20/40 or better.

Humans↗
PubMed2000

Which ocular and neurologic conditions cause disparate results in visual acuity scores recorded with visually evoked potential and teller acuity cards?

PURPOSE: We investigated whether disparity between visually evoked potential (VEP) acuity scores and Teller Acuity Card (TAC) scores varied according to presence of ocular or neurologic conditions. METHODS: Charts from 175 children (mean age, 34.8 months; range, 3 to 158 months) referred for visual acuity testing were examined. All children had been tested with pattern-alternation VEP and TAC and had undergone a complete eye examination. VEP and TAC acuity scores were relative to age-expected acuity scores for each acuity test. The absence and degree of macular abnormality, retinal abnormality, optic nerve hypoplasia, optic nerve atrophy, cortical visual impairment, developmental delay, cerebral palsy, seizures, and nystagmus were noted. Analysis of variance models were used to determine whether differences between VEP and TAC scores varied according to the presence of specific deficits. Logistic regression analysis determined whether degree of specific deficits was associated with a greater chance of inconsistency between VEP and TAC scores (>0.3 log unit difference). RESULTS: Inconsistent scores were found in 48% of children. Developmental delay was associated with relatively poorer TAC than VEP score, and the chance of inconsistency increased with severity of developmental delay. CONCLUSIONS: Diagnosis-dependent variability exists between TAC and VEP scores. Therefore knowledge of the clinical picture is necessary in interpretation of VEP and TAC scores. It is not clear which test is more useful when a disparity exists, either from this or previous studies. When visual acuity is assessed longitudinally in a given child, then consistency in method for acuity assessment is important.

Aging↗
PubMed1995

[The Freiburg Vision Test. Automated determination of visual acuity].

The Freiburg Visual Acuity Test is an automatic computerized procedure for self-administered measurement of visual acuity. Landolt-Cs are presented on a monitor in one of eight orientations. The subject presses one of eight buttons, which are spatially arranged according to the eight possible positions of the Landolt-C's gap. To estimate the acuity threshold, a best-PEST procedure is employed, assuming a psychometric function with a constant slope on a logarithmic acuity scale. The discreetness artifacts in computer monitors limit the presentation of small stimuli. By anti-aliasing (smoothing of contours by gray-shading), the spatial resolution was improved by a factor of four, such that the shape of Landolt-Cs with oblique gaps is adequate and visual acuities from 0.06 up to 3.6 can be tested at a distance of 5 m.

Artifacts↗
PubMed2003

Beyond visual acuity: new and complementary tests of visual function.

Visual acuity is an essential component of the routine ophthalmic examination and the most common measure of visual function. There is increasing recognition, however, of the need to evaluate visual function beyond the limited extent afforded by visual acuity. The primary objective of this article is to introduce a variety of new and lesser-used techniques for measuring visual function that complement visual acuity assessment, each of which has been shown to detect visual dysfunction in patients with normal visual acuity.

Color Perception↗
PubMed1986

Visual acuity in newborn and preterm infants measured with grating acuity cards.

Binocular visual acuity of normal newborn infants, preterm newborn infants, and newborn, full-term infant patients with nonophthalmologic abnormalities was measured by means of grating acuity cards. Each test took about six minutes to complete, and 89% of the tests (154 of 174) were successful. Visual acuity of infants at 39 to 40 weeks of gestational age was about 0.023 stripes per minute of arc, or 0.69 cycles per degree (20/866). Between 34 and 44 weeks of gestational age, visual acuity improved at the rate of 0.46 octaves per month. This test is simple, fast, and reliable, and requires no apparatus except the cards themselves.

Gestational Age↗
PubMed2006

Posterior capsule opacification: comparisons between morphology, visual acuity and self-assessed visual function.

PURPOSE: To investigate whether posterior capsule opacification (PCO) morphology, visual acuity (VA) and self-assessed visual function correlate, and to compare perceived visual disabilities with those of cataract patients with corresponding VA. METHODS: Twenty-one patients with PCO were examined before capsulotomy. In adjunct to the ophthalmological examination, the patients completed a Catquest questionnaire and a digitized retroillumation image was acquired. The images were analysed with the Evaluation of Posterior Capsule Opacification (EPCO) program. Data for visual function were compared with data from the National Swedish Cataract Register (NCR). RESULTS: The epco values were correlated with VA in the PCO eyes: the higher the epco score, the lower the VA. There were also correlations between the epco scores, satisfaction with vision, and perceived disabilities in daily life. Symptoms of glare were not significantly correlated with epco scores or with VA. Visual acuity in PCO eyes was better correlated with perceived disabilities and satisfaction with vision than VA in eyes with cataract. CONCLUSIONS: There was a significant correlation between epco scores and VA and between epco scores and Catquest. Consequently, the morphological method was related to the self-assessed visual function. Patients with PCO seemed to have more disturbed visual function, as defined by Catquest, than cataract patients with the same VA.

Adult↗
PubMed1986

Visual acuity and the flash visually evoked cortical potential in albinos.

The flash visually evoked cortical potential (VECP) was recorded in 18 human albinos. In some individuals P2 (latency 100-120 msec) formed the major component while in others P1 (latency 60-80 msec) was the largest component and dominated the response. The relative amplitude of P1 compared to P2 was calculated, and the results compared to the levels of monocular Snellen Visual Acuity measured. A relationship was found such that the greater the amplitude of P1 compared to P2, the lower the level of acuity. (Group 1: rs = -0.509, P less than 0.05. Group 2: rs = -0.536, P less than 0.05).

Adolescent↗
PubMed2002

Visual acuity and quality of life outcomes in cataract surgery patients in Hong Kong.

BACKGROUND: Visual acuity, visual functioning, and vision related quality of life outcomes after cataract surgery were assessed in a population based study in a suburban area of Hong Kong. METHODS: A cluster sampling design was used to select apartment buildings within housing estates for enumeration. All enumerated residents 60 years of age or over were invited for an eye examination and visual acuity measurement at a site within each estate. Visual functioning (VF) and vision related quality of life (QOL) questionnaires were administered to interview subjects who had undergone cataract surgery and to unoperated people with presenting visual acuity less than 6/60 in either eye, and a sample of those with normal visual acuity. RESULTS: 36.6% of the 310 cataract operated individuals had presenting visual acuity 6/18 or better in both eyes, and 40.0% when measured by pinhole. 4.5% were blind, with presenting visual acuity less than 6/60 in both eyes. Of operated eyes, 59.6% presented with visual acuity 6/18 or better. 11.2% of the operated eyes were blind with vision less than 6/60. Visual acuity outcomes 6/18 or better were marginally associated with surgery in private versus public hospitals. Lens status (pseudophakic versus aphakic) and surgical period (within the most recent 3 years versus before) were not significantly related to vision outcomes. Mean VF and QOL scores decreased consistently with decreasing vision status. Spearman correlation with vision status was 0.420 for VF scores and 0.313 for QOL scores. Among VF/QOL subscales, correlation was strongest for visual perception (r = 0.447) among VF subscales and weakest for self care (r = 0.171) among QOL subscales. Regression adjusted VF and QOL total scores for cataract operated individuals were slightly lower than for those of visually comparable unoperated individuals (p<0.05). CONCLUSIONS: Cataract operations in Hong Kong did not consistently produce good presenting visual acuity outcomes, suggesting that postoperative monitoring would be useful to minimise visual impairment in this population. Although vision outcomes were consistently correlated with all VF/QOL subscale scores, there was a differential impact with VF subscales usually being affected more by reduced acuity than the more general QOL subscales.

Aged↗
PubMed1994

The Cardiff acuity test used for measuring visual acuity development in toddlers.

The Cardiff acuity test was used in estimating the binocular and monocular visual acuity norms of 231 toddlers between 12 and 36 months. Mean binocular acuity increased from 4.5 to 1.2 min arc and monocular acuity from 4.5 to 1.4 min arc over the age range. Interocular acuity difference was not significant and for 99% of the children, the difference in acuity estimate was < or = 1/3 octave. Success rates ranged from 96 to 100% for binocular tests but fell to a range of 41-91% for monocular testing. Acuity assessment was fast and the intraobserver reliability was high. Age norms of visual acuity useful in clinical settings are presented for toddlers between the ages of 12 and 36 months.

Child Development↗
PubMed2005

Comparison of the potential acuity meter and pinhole tests in predicting postoperative visual acuity after cataract surgery.

PURPOSE: To compare the accuracy of potential acuity meter (PAM) and pinhole (PH) tests in predicting visual acuity after cataract surgery. SETTING: Department of Ophthalmology and Visual Sciences, University of the Philippines, Philippine General Hospital, Manila, and Asian Eye Institute, Makati, Philippines. METHODS: This prospective study comprised 64 eyes with mild to moderate cataract that had uneventful phacoemulsification. The PAM and PH tests were performed to predict postoperative visual acuity. Best corrected visual acuity (BCVA) 4 weeks after surgery was compared with the predicted visual acuity. The number of lines of inaccuracy was calculated by subtracting the BCVA from the predicted visual acuity. The variables analyzed were type of predictive test and preoperative BCVA. The eyes were divided according to preoperative BCVA as follows: Group 1, 20/20 to 20/50; Group 2, 20/60 to 20/100; Group 3, 20/200 or worse. RESULTS: The PH predicted visual acuity was correct in 5% of eyes and the PAM predicted acuity, in 17%. The PH predicted acuity was accurate within 1, 2, and 3 lines of BCVA in 23%, 40%, and 54% of eyes, respectively, and the PAM predicted acuity, in 64%, 81%, and 92% of eyes, respectively. The mean number of lines of inaccuracy was significantly less with the PH than with the PAM (3.47 lines +/- 2.42 [SD] and 1.60 +/- 1.55 lines, respectively) (P=.0005). The mean lines of inaccuracy in Group 1 were 2.49 +/- 1.52 for the PH and 1.14 +/- 0.99 for the PAM (P=.027); in Group 2, 3.17 +/- 1.99 PH and 1.65 +/- 1.80 PAM (P=.642); and in Group 3, 6.58 +/- 3.03 PH and 2.67 +/- 2.10 PAM (P=.240). CONCLUSIONS: The PAM was more accurate than the PH in predicting visual acuity after cataract surgery. The accuracy of both tests decreased in patients with poorer preoperative visual acuity.

Aged↗
PubMed2004

[Presentation of visual acuity in ophthalmological publications].

BACKGROUND: Visual acuity is one of the most important functions of the visual system. Visual acuity is the basis of many decisions in clinical practice. The assessment of visual acuity is clearly defined (norm EN ISO 8596). In this study, the presentation of results of visual acuity assessments in the ophthalmological literature was analysed. MATERIALS AND METHODS: All the issues of the journals "Klinische Monatsblatter fur Augenheilkunde" and "Der Ophthalmologe" of the years 2002 and 2003 were reviewed especially concerning the procedure of visual acuity assessment, the scaling in the lower visual acuity range, axis scaling and the calculation of mean values of visual acuity. RESULTS: In total, 550 publications were reviewed. Of these papers, 207 contained at least one visual acuity value and 42 papers presented detailed data concerning either the change of visual acuity over a certain time interval, or mean values, or using charts. A linear scale was used in 9 of 28 papers with presentation of visual acuity measurements in a chart. Of 32 publications with visual acuity measurements less than 0.2, only 2 used a logarithmic scale in the lower visual acuity range, while in 14 papers, scaling was rather rough or not numeric (e. g., counting fingers). Sixteen papers used the units "finger counting" or "hand movements" to describe low visual acuities. The way of calculating mean values remained obscure in 36 papers. CONCLUSIONS: Regarding a correct assessment of visual acuity and the effect of therapy, the fundamental guidelines of visual acuity assessment and its correct presentation should be considered.

Humans↗
PubMed2005

Development of visual acuity in children with cerebral visual impairment.

OBJECTIVE: To study the development of visual acuity in term-born children with cerebral visual impairment and a history of neonatal hypoxic-ischemic encephalopathy. METHODS: We studied 19 term-born children, aged 6 months to 6 years, with moderate to severe neonatal hypoxic-ischemic encephalopathy and behaviors indicative of cerebral visual impairment. Longitudinal measures of grating acuity were obtained using preferential looking (PL) and visual evoked potential (VEP) procedures. Visual acuities at first and last visits were compared. The courses of acuity development in the 9 children who underwent both VEP and PL acuity assessment at 4 or more ages were compared with normal development. RESULTS: All children had measurable PL and VEP acuity, despite poor visual behavior. In nearly all, both PL and VEP acuity were below normal for age. For both PL and VEP measures, acuity at the last visit was, on average, 1 octave better than at the first visit, with a rate of improvement lower than normal. Although parallel courses of PL and VEP development occurred in many, substantial disparities in PL and VEP acuity were observed in others. CONCLUSIONS: Modest increases in PL and VEP grating acuity occur during early childhood in many of these patients. The rate of increase is lower than normal.

Blindness, Cortical↗
PubMed2004

Visual acuity and the ability of the visually impaired to read medication instructions.

BACKGROUND/AIMS: Although medical information is often communicated in writing, little attention is given as to whether patients can read it--for example, the miniscule writing on the side of the medication bottles (equivalent to 6/6 reduced Snellen). The authors wished to determine a distance visual acuity threshold, using routine assessments of visual acuity (VA), beyond which patients are unable to read their instructions. METHODS: 180 patients, subgrouped according to the best line of Snellen acuity (from 6/9 to 6/60) achieved in either eye were recruited. Subjects were asked to read the printed manufacturer's instructions on the side of the drops box without magnification. RESULTS: Those subjects with best corrected VA of lower than or equal to 6/24 showed a significantly diminished ability to read the instructions on their eye drops bottles (p<0.001 for each comparison). When this group selected a font size of their choosing, the mode for preferred Arial font sizes were 16 for the 6/24 group, 18 for 6/36, and 22 for 6/60. CONCLUSION: This study documents the inability of patients with visual impairment to read the instructions on their bottle of eye drops. There is evidence of a distance VA threshold effect such that, although the majority of patients with 6/18 VA are able to read their instructions, patients whose VA is worse cannot. This latter group would benefit from a larger font size, a size of Arial 22 being sufficient. We recommend that all printed information for patients with visual acuities between 6/24 and 6/60 be printed in font Arial 22 or equivalent.

Adult↗