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Results for “Visual Acuity”

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At least 631 records · Page 35Linked to original sources

PubMed1995

Visual acuity as a prognostic indicator in stage I macular holes. The Vitrectomy for Prevention of Macular Hole Study Group.

PURPOSE/METHODS: To evaluate the role of initial visual acuity as a factor for progressive loss of vision or progression to a full-thickness macular hole in eyes with stage I macular holes (tractional foveal detachment without dehiscence). The study population included 35 patients with stage I macular holes with best-corrected visual acuity of 20/25 to 20/80 in one eye, and a full-thickness macular hole in the fellow eye. RESULTS/CONCLUSIONS: Eyes with stage I macular holes with best corrected visual acuity between 20/50 and 20/80 had a 66% (ten of 15 eyes) rate of progression to full-thickness macular hole, whereas eyes with best-corrected visual acuity of between 20/25 and 20/40 had a 30% (six of 20 eyes) risk of progression to full-thickness macular hole. The risk of progression to macular hole is significantly higher in eyes with stage I macular holes with best-corrected visual acuity of 20/50 or worse (P = .03).

Aged↗

PubMed2005

A novel method for assessing variations in visual acuity after the blink.

A novel instrument was developed to assess the visual acuity in correlation with time after blink. The method uses an optical blink detector which triggers the display of a random target symbol on a computer monitor. The delay time between blink and symbol display varies randomly from blink to blink, the exposure duration is fixed at 100 ms. The subject has to identify the correct symbol, a score is kept of the correct responses in correlation to delay time. The recovery of visual acuity after blink was measured for subjects wearing two types of bifocal contact lenses and a control group of non-contact lens wearers. All groups required between 200 and 500 ms to achieve their best visual acuity. Subjects wearing the translating bifocal lenses recovered their vision significantly faster than the subjects wearing no lens or the simultaneous vision bifocal lens.

Adult↗

PubMed1982

Macular vasculature, visual acuity, and irreversibly sickled cells in homozygous sickle cell disease.

Observations of visual acuity and the conjunctival, macular, and perimacular vascularity have been assessed in patients with homozygous sickle cell (SS) disease. There were 17 matched pairs, each consisting of one patient with a high count (greater than or equal to 15%) and one with a low count (less than or equal to 5%) of irreversibly sickled cells (ISCs). The macular vascular bed was assessed by measurements of the foveal avascular zone (FAZ), perimacular avascular zones, and counts of perimacular vascular abnormalities (perimacular counts). Small foveal avascular zones and high perimacular counts were commoner in younger than older patients and there was a significant inverse correlation between size of the FAZ and the perimacular count. These observations were compatible with the hypothesis that perimacular vessel anomalies represent the early vaso-occlusive phase which progresses to ischaemia and the formation and enlargement of avascular areas. Visual acuity was assessed by Snellen's test type and by measuring contrast sensitivity. There was no obvious relationship between acuity measured by the 2 methods and no relationship between acuity and observations of macular vascularity. High ISC counts were significantly related to abnormalities of the conjunctival vasculature, but no relationship was noted with abnormalities of the macular vasculature or with visual acuity.

Adult↗

PubMed2006

Determinants of health related quality of life and health state utility in patients with age related macular degeneration: the association of contrast sensitivity and visual acuity.

BACKGROUND: There has been increasing interest in the use of measures of health related quality of life (HRQoL) and health state utility values in Age Related Macular Degeneration (ARMD). Visual acuity has been found to be an important determinant of such measures in previous studies. More recently, another measure of visual impairment, contrast sensitivity has received considerable attention. We designed a study to examine whether the contribution of contrast sensitivity in explaining HRQoL and health utilities over and above that of visual acuity. METHODS: 209 patients with unilateral or bilateral ARMD were recruited into a cross-sectional study of patients from a large teaching hospital. Patients underwent visual tests (near and distant visual acuity, contrast sensitivity) and completed a vision function questionnaire, the VF-14, HUI3, and time trade-off. RESULTS: Using multivariate regression analysis, the study revealed that contrast sensitivity remained a statistically significant predictor of all outcome measures even when visual acuity was included. This result was supported by the correlation coefficients between measures. CONCLUSIONS: The measurement of contrast sensitivity appears to be better related to a person's HRQoL and health utility. Future studies should consider incorporating contrast sensitivity in addition to visual acuity. Studies, in particular economic evaluations, may underestimate the effect of treatment unless contrast sensitivity is considered.

Adult↗

PubMed1976

New design principles for visual acuity letter charts.

This paper intoduces new principles for the design and use of letter charts for the measurement of visual acuity. It is advocated that the test task should be essentially the same at each size level on the chart. Such standardization of the test task requires the use of letters of equal legibility, the same number of letters on each row, and uniform between-letter and between-row spacing. It is also advocated that, combined with the test task standardization, there should be a logarithmic progression of letter size. Charts incorporating these design features have been made. These charts facilitate the use of nonstandard testing distances which might be used when there is low visual acuity, when examination room layout prevents testing at the standard distance, or when it is necessary to validate visual acuity scores or detect malingering. Adjusting the visual acuity score according to the chosen testing distance is simplified by the use of logarithmic scaling.

Humans↗

PubMed2005

Acute-onset endophthalmitis after cataract surgery (2000-2004): incidence, clinical settings, and visual acuity outcomes after treatment.

PURPOSE: To report the incidence, clinical settings, and visual acuity outcomes of acute-onset endophthalmitis after cataract surgery. DESIGN: Retrospective, observational case series. METHODS: Annual cataract surgery statistics were determined by review of electronic surgical records. The clinical and microbiologic records were reviewed of all patients with clinically diagnosed endophthalmitis within 6 weeks after cataract surgery at a single university-affiliated hospital between January 2000 and November 2004. main outcome measures: Operative technique, intraoperative complications, and visual acuity. RESULTS: The incidence of acute-onset endophthalmitis after cataract surgery was 0.04% (7/15,920) for cataract surgeries of all methods, 0.05% (6/11,462) for cataract surgery by clear cornea phacoemulsification, and 0.02% (1/4,458) for cataract surgery by methods other than clear cornea phacoemulsification (P = .681, Fisher's exact test). Six of seven (86%) cases occurred in the right eye, and all cases were performed by right-handed surgeons through temporal incisions. Five of seven (71%) patients had relative immune compromise. Four of seven (57%) patients had an intraoperative complication: vitreous loss in three patients and iris prolapse in one patient. Two patients had topical placement of lidocaine 2% gel before povidone-iodine preparation. The visual acuity at final follow up was 20/25 or better in four patients and count fingers or worse in three patients. CONCLUSIONS: The incidence of acute-onset endophthalmitis after temporal clear cornea incision phacoemulsification is low (0.05%). Potential risk factors for endophthalmitis may include intraoperative complications, relative immune compromise, application of lidocaine 2% gel before povidone-iodine preparation, and inferior incision location.

Acute Disease↗

PubMed2006

N-3 fatty acids and cognitive and visual acuity development: methodologic and conceptual considerations.

Several randomized clinical studies in infants born preterm and at term have explored the effects on visual acuity development of postnatal supplementation with various sources of docosahexaenoic acid (DHA). Higher visual acuity after DHA supplementation is a consistent finding in infants born preterm. For infants born at term, the results are less consistent and are better explained by differences in sensitivity of the visual acuity test (electrophysiologic tests being more sensitive than subjective tests) or by differences in the amount of DHA included in the experimental formula. Differences in the sensitivity of the test may also be relevant in discussions of whether the effects of DHA on visual acuity are transient or persistent. A smaller number of studies have attempted to study the effects of DHA on cognitive development. The major focus of this article is to review the types of methods that have been used to evaluate the effects of DHA on cognition and to provide the rationale for measures that are a better conceptual fit. Research is needed (1) to probe the effects of variable DHA exposure on infant and child development, (2) to measure outcomes that better relate to preschool and school-age cognitive function, and (3) to reinforce, and in some cases demonstrate, links between specific infant and preschool measures of cognitive development. We strongly encourage collaborations with developmental cognitive neuroscientists to facilitate these research goals.

Child, Preschool↗

PubMed1992

Prediction of visual acuity recovery in cystoid macular edema.

Three consecutive patients participated in a prospective evaluation of pseudophakic cystoid macular edema. The duration of the macular edema ranged from 6 to 8 months. On the initial visit, the best corrected acuity with spectacles was determined and a potential acuity meter reading was obtained; this test suggested potential for visual recovery in two of the three patients. Sub-tenon's injections of methylprednisolone acetate (20 mg) were administered along with topical 1% prednisolone acetate and 1% atropine. One month later, visual acuity was improved by more than 2 Snellen lines in all three of the patients. A visual acuity measurement with the potential acuity meter that is better than the best corrected acuity with spectacles may reflect the presence of intact, but dysfunctional photoreceptors that are capable of restoring visual acuity upon resolution of the edema.

Aged↗

PubMed1976

Readability of approach charts as a function of visual acuity, luminance, and printing format.

This study determined the ability of 12 presbyopic subjects to read numerals from aeronautical approach procedure charts. The readability of chart numerals was determined for 15 size and contrast combinations as a function of near visual acuity (equivalent 20/20, 20/40, and 20/60) and chart brightness (100 and 1.0 ft L). Test subjects were evaluated at the normal near-visual-acuity level (20/20) and the minal near-visual-acuity levels (20/40) for Classes I and II and 20/60 for Class III) as specified in the FAA's Guide for Aviation Medical Examiners. The results indicated that subjects with 20/20 near visual acuity could read all chart numerals under bright and dim luminance conditions. Subjects with 20/40 and 20/60 levels of near visual acuity experienced reading difficulty under bright conditions and increased difficulty under dim luminance.

Aerospace Medicine↗

PubMed1979

[The determination of the maximal angular visual acuity and of the Vernier acuity (author's transl)].

In clinical diagnosis it is important to determine the maximal angular visual acuity by using for example the TNO Landolt C ring chart of Vos. The determination of the Vernier- or Nonius acuity is hardly of any clinical diagnostic significance because in several pathological conditions and in normal eyes the visual acuity is always three times higher than the angular visual acuity. Therefore this does not contribute to further differentiation.

Amblyopia↗

PubMedDate not supplied

Visual acuity after vitrectomy and epiretinal membrane peeling with or without premacular indocyanine green injection.

PURPOSE: To compare postoperative visual acuity of eyes operated for an epiretinal membrane (ERM), with or without intraoperative intraocular indocyanine green (ICG) injection. METHODS: Retrospective study of 75 pseudophakic eyes with epiretinal membrane operated by vitrectomy-peeling. In 20 cases operated in 2001 and 2002 (Group 1), ICG diluted in 5% glucose solution was injected intraoperatively into the vitreous. In another group of 55 cases operated between 1996 and 1999 (Group 2), ICG was not used. RESULTS: The mean visual acuity was 0.32(+1) and 0.32(+2) preoperatively, 0.4(+2) and 0.5 at 1 month, and 0.63 and 0.63(+2) on the final examination in Groups 1 and 2, respectively. Visual acuities were not significantly different between the two groups. CONCLUSIONS: Premacular injection of ICG during vitrectomy to facilitate epiretinal membrane peeling did not appear to compromise postoperative improvement of visual acuity. However, its use is questioned since it did not yield better postoperative results and because potential toxic adverse reactions could not be excluded by this study.

Adolescent↗

PubMed1989

[The incidence of decreased visual acuity (far and near) among 5th- to 8th-grade pupils of the general education schools in the city of Chernovtsy].

Examination of 4159 pupils of the 5th-8th forms in schools of general education in a town of Chernovtsy has revealed decreased visual acuity for far in 16.2% and for near--in 30.3% of eyes. Decreased visual acuity for near with normal vision for far was revealed in 20.9% of the pupils. The incidence of decreased visual acuity was higher in winter than in autumn and spring. In conducting mass examinations of schoolchildren, it is recommended to determine visual acuity not only for far, but for near as well. In cases of decreased visual acuity for near (not lower than 0.8) it is not recommended to master professions connected with a strained visual load at a near distance.

Adolescent↗

PubMed2006

Visual acuity comparison of vitrectomy with and without internal limiting membrane removal in the treatment of diabetic macular edema.

PURPOSE: To evaluate whether internal limiting membrane (ILM) peeling during vitrectomy affects vision outcome in patients with diabetic macular edema. MATERIAL AND METHOD: Fifty-eight eyes of 49 patients were included in the study. Patients with persistent diffuse clinically significant macular edema were divided into two groups according to the surgical method used. Group I subjects (15 patients; mean age 56.60+/-8.50 years; 17 eyes total) underwent vitrectomy with ILM peeling. Group II subjects (34 patients; mean age 57.52+/-11.54 years; 41 eyes total) underwent vitrectomy without ILM peeling. The data recorded for each case were type and duration of diabetes, insulin treatment (yes/no), presence of arterial hypertension, stage of diabetic retinopathy, lens status, history of macular laser treatment, and detection of posterior vitreous detachment during surgery. Visual acuity was measured preoperatively and 1 year postoperatively in decimal notation, and values were converted to logarithm of minimal-angle-of-resolution (logMAR) scores. Mean pre- and postoperative visual acuity were compared within each group, and the mean change in visual acuity in Group I was compared to that in Group II. RESULTS: There were no significant differences between the groups with respect to age; sex distribution; diabetes type; duration of diabetes; numbers of patients on insulin treatment; frequencies of hypertension, proliferative diabetic retinopathy, previous macular laser treatment; or frequency of intraoperatively confirmed posterior vitreous detachment (chi-square, P>0.05 for all). Comparison of pre- and post-operative visual acuity revealed significant improvement in both Group I (1.15+/-0.307 vs. 0.764+/-0.355 logMAR, respectively; Wilcoxon rank test, P<0.01) and Group II (1.22+/-0.516 vs. 0.829+/-0.436 logMAR, respectively; Wilcoxon rank test, P<0.001). The change in visual acuity for Group I was not significantly different from that observed in Group II (0.391+/-0.335 vs. 0.393+/-0.273 logMAR, respectively; Mann-Whitney U test, P>0.05). CONCLUSION: The visual acuity outcomes in the study indicate that vitrectomy without ILM peeling is just as effective as vitrectomy with ILM peeling in the treatment of diabetic macular edema. Both techniques led to significant and similar degrees of improvement in visual acuity.

Diabetic Retinopathy↗

PubMed2001

Hypotony maculopathy: improvement of visual acuity after 7 years.

PURPOSE: To describe a 79-year-old Caucasian male with a history of hypotony maculopathy for 7 years after cataract extraction with subsequent recovery of normal intraocular pressure and improvement of visual acuity. METHODS: Interventional case report. The patient developed an intraocular pressure ranging from 0 to 5 mm Hg after cataract surgery. He developed hypotony maculopathy, and the visual acuity declined to 20/200. On evaluation 7 years later, a superior cyclodialysis cleft was detected and treated with the argon laser. RESULTS: Closure of the cleft with argon laser was successful. The intraocular pressure stabilized at 17 to 20 mm Hg, and the visual acuity improved to 20/30. CONCLUSION: The development of hypotony maculopathy leads to impairment of visual acuity. This case demonstrates that visual acuity can improve after resolution of the maculopathy even after several years of hypotony.

Aged↗

PubMed2005

Effects of prenatal alcohol exposure on infant visual acuity.

OBJECTIVE: To examine the effects of prenatal alcohol exposure ascertained prospectively on infant visual acuity across a range of exposures and factors that mediate or moderate these effects. STUDY DESIGN: Infant visual acuity was examined in 131 Cape Coloured (mixed ancestry) maternal-infant pairs in Cape Town, South Africa. Drinking patterns were documented by maternal reporting during pregnancy. Grating acuity was assessed with Teller Acuity Cards (TAC) at 6.5 months after term. Data were analyzed by correlation, multiple regression, and analysis of variance. RESULTS: Greater average daily prenatal alcohol exposure was related to poorer acuity, as indicated by lower TAC scores. The effect of alcohol on acuity was significant primarily for infants born to mothers > or =30 years of age at delivery, in comparison to infants born to younger mothers. This effect was not mediated by gestational age or birth size or attributable to alcohol-related neurocognitive deficits. CONCLUSIONS: This study linked prenatal alcohol exposure ascertained prospectively to poorer visual acuity in infancy. The results are consistent with clinical and animal evidence of alcohol-related disruption of the visual system.

Adult↗

PubMed1997

Removal of retained lens fragments after phacoemulsification reverses secondary glaucoma and restores visual acuity.

PURPOSE: The purpose of the study is to evaluate the effect of vitrectomy on secondary glaucoma and visual acuity outcomes in patients with retained lens fragments after phacoemulsification. METHODS: A retrospective analysis of 126 patients who had vitrectomy for retained lens fragments after phacoemulsification during the 3-year period between January 1, 1993, and December 31, 1995. RESULTS: Glaucoma, defined as an intraocular pressure of greater than or equal to 30 mmHg, occurred in 42 (36.8%) of 114 patients before vitrectomy and in 4 patients (3.2%) of 126 after vitrectomy. There were no differences in the rates of persistent glaucoma regardless of the intervals between cataract surgery and the vitrectomy: less than or equal to 1 week, 2 patients (4.1%); greater than 1 week to less than or equal to 4 weeks, 1 patient (2.5%) and greater than 4 weeks, 1 patient (2.6%). The visual acuity was 20/40 or better in 13 patients (11.4%) before vitrectomy and in 75 patients (59.5%) after vitrectomy. The rates of visual acuity 20/40 or better also were similar for all intervals: less than or equal to 1 week, 29 patients (59.2%); greater than 1 week to less than or equal to 4 weeks, 22 patients (56.4%) and greater than 4 weeks, 24 patients (63.1%). CONCLUSIONS: Vitrectomy for removal of retained lens fragments reduces secondary glaucoma and yields favorable visual acuity outcomes. In eyes with elevated intraocular pressure, early vitrectomy generally is recommended, but delayed vitrectomy also has favorable outcomes.

Adult↗

PubMedDate not supplied

Occurrence and predictors of retinopathy and visual acuity in Type 2 diabetic patients and control subjects. 10-year follow-up from the diagnosis.

The evolution of visual acuity and retinopathy and their risk factors in patients with newly diagnosed type 2 diabetes and in control subjects. A 10-year prospective study consisting of a representative group of 133 (70 men, 63 women) newly diagnosed type 2 diabetic patients diagnosed at health centers between 1979 and 1981 and 144 (62 men, 82 women) non-diabetic control subjects recruited from the population register. The frequency of retinopathy was determined by grading of 45 degrees fundus photographs at baseline and after 5 and 10 years. By the 10-year follow-up the diabetic patients had lower visual acuity than the control subjects. The impairment of the visual acuity correlated inversely to HbA(1C) value of the 5-year examination. The frequency of retinopathy in type 2 diabetic patients increased sharply after 5 years and at 10-year 55% of diabetic patients had signs of retinopathy. The frequency of retinopathy in the control subjects was low, but detectable. In the diabetic patients poor glycemic control was the most important predictive factor for the development of retinopathy. In the control subjects blood pressure levels were higher and microalbuminuria more common in those with than in those without retinopathy. The visual acuity deteriorated and the frequency of retinopathy increased in newly diagnosed type 2 diabetic patients with duration of disease and poor glycemic control. Interestingly, higher blood pressure levels and microalbuminuria predicted retinopathy in control subjects.

Blood Glucose↗

PubMedDate not supplied

Visual acuity and 10 degrees automated static perimetry in eyes with retinitis pigmentosa.

PURPOSE: In a previous study we demonstrated that the progression of the disease retinitis pigmentosa (RP) can be readily monitored by the mean deviation (MD) measured by Humphrey central 10-2 perimetry, which assesses the sensitivity distribution in the macular area in eyes affected by RP. In the present study, we investigated whether the 10 degrees perimetric results could predict the time of declining visual acuity in eyes with RP in a cross-sectional study. METHODS: Humphrey 10-2 perimetry results and visual acuity were studied in the right eyes of 69 patients with typical RP. Patients whose eyes had cataract, glaucoma, cystoid macular edema, or other complications affecting vision were excluded. RESULTS: Eyes with an MD of -15 dB or greater had almost normal visual acuity. Various degrees of visual acuity loss were observed in eyes with an MD of less than -15 dB. In the 35 eyes with an MD of less than -15 dB, visual acuity correlated well with the corrected pattern standard deviation (CPSD), which is the measure of the degree to which the shape of the measured field departs from the age-corrected normal reference field. CONCLUSION: In the absence of complications, many eyes with RP may experience acuity loss after the field constriction reaches an MD of less than -15 dB. The CPSD may be used as an indicator of acuity because eyes showing a lower CPSD tend to have greater loss of acuity among eyes with an equivalent MD value.

Adolescent↗