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At least 811 records · Page 45Linked to original sources
PubMed2006

Screening amblyopia of preschool children with uncorrected vision and stereopsis tests in Eastern Taiwan.

UNLABELLED: AIMS OR PURPOSE: Screening for amblyopia at earliest age is important for early treatment and better prognosis. This study aimed at evaluating the validity of uncorrected distant and near visual acuity and random dot stereopsis for screening amblyopia. METHODS; In Eastern Taiwan, population-based screen tests were performed for children at age from 3 to 6 years. The tests included uncorrected distant and near visions and random dot stereopsis (300 s) test. The screen performers were registered nurses of local public health service posts. The golden standards of the tests were the results of examination by the ophthalmologists. RESULTS: Including Hans and aboriginal Taiwanese, 5232 children were included. Screened by distance visual acuity with different cutoffs and near visual acuity, 10.3, 30.3 and 8.2% children were abnormal. Screened by random dot, only 2% children were abnormal. By a senior ophthalmologist, 115 amblyopic children were diagnosed amblyopic. The sensitivities of distance visual acuity with low/high cutoff and near visual acuity were 74.7/84.8 and 49.4%, whereas that of the NTU random dot stereogram was 20.5%. Simultaneous testing of either two of the three tests improved the sensitivity. CONCLUSION: Screening for amblyopia by the local nurses using the visual acuity tests or random dot stereopsis test alone does not display a high sensitivity. Simultaneous testing of distant visual acuity and stereopsis test elevate the sensitivity and preserve the specificity.

Amblyopia↗
PubMedDate not supplied

[New method of visual fields color division in diploptic treatment of strabismus].

A new method of color division of the visual fields based on polarized light interference is described. A new method for diploptic therapy of strabismus is developed, based on the above principle and possessing numerous advantages. The method was used in 38 patients with binocular disorders of various severity; binocular function improved in 18. The method is particularly effective in the patients with correct position of the eyes with bifoveal fusion on the synaptophore and parallel color test vision and in the patients with binocular vision and amblyobinopia.

Child↗
PubMedDate not supplied

Is membrane extraction in cases of exudative age-related macular degeneration still up-to-date? A 4-year résumé.

BACKGROUND: Age-related macular degeneration (AMD) is a frequent cause of an irreversible loss of the ability to read. The non-exudative form of AMD has not been therapeutically approached in the past in contrast to the exudative form with choroidal neovascularizations (CNVs). Parafoveal laser coagulation can be applied, and in cases of subfoveal location a pars plana vitrectomy with subretinal resection of the CNV is possible. MATERIAL AND METHODS: Since 1995, we have operated 46 eyes of 45 patients with CNV developing from AMD. Patient ages ranged from 63 to 85 years (mean 71.8 years). Pre- and postoperatively we performed vision tests, fluorescence angiographies with sodium fluorescein and indocyanine green. Follow-up times ranged from 3 to 28 months (mean 12.3 months). RESULTS: Pre-operative vision was 0.10 (range: hand movements to 0.4). Postoperative vision at the end of the follow-up period was 0.12 (range: hand movements to 0.4). Vision at the end of the follow-up was lower in 41%, unchanged in 20% and improved in 39%. In 43 eyes, a non-exudative form of AMD developed. Two eyes had a recurrent CNV, which was removed successfully with a second pars plana vitrectomy. Three patients developed a retinal detachment, which was successfully treated by pars plana vitrectomy, encircling buckle and gas tamponade. CONCLUSIONS: We still have to wait for the results of the photodynamic study trials and a randomized study of macular dislocation. Subretinal removal of the CNV by pars plana vitrectomy allows a stabilization of the visual function in most of our cases of AMD. This method inhibits the development of large pseudotumour-like scars. Postoperatively remaining pigment epithelial defects with choroidal atrophies however limit a visual rehabilitation so that reading vision can only be achieved in cases with good pre-operative vision. Long-term results of photodynamic therapy are still lacking and have to show its effectiveness over greater time spans.

Aged↗
PubMed1988

Heterozygote detection in X-linked recessive incomplete achromatopsia.

Carrier women in a family with X-linked incomplete achromatopsia (XLIA) were evaluated by means of ophthalmologic examinations, psychophysical tests, and electroretinography (ERG). Ophthalmologic examinations of five obligate carrier women and three women at 50% risk were normal except for the finding of high myopia in one carrier and one woman at risk. Detailed color vision testing was normal in all eight women. By contrast, the corneal full-field ERGs of three of five obligate carriers and two of three women at risk displayed major, qualitatively similar abnormalities of their cone components that were readily detected by our quantitative method. These b-wave alterations were similar in all five women regardless of refractive error. Our findings suggest that the ERG can identify some women who carry the gene for this X-linked recessive condition who are normal by clinical and psychophysical testing.

Adult↗
PubMed2005

Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopia.

Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7-12 years and 18-35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia.

Adolescent↗
PubMed2006

Assessment of colour differences in silicone hand and digit prostheses: perceptible and acceptable thresholds for fair and dark skin shades.

This study addresses the dilemma of initial clinical and social acceptance of a newly fabricated silicone prosthesis in relation to its colour match to the natural skin. This was achieved by derivation of specific colour difference thresholds defining perceptible and acceptable levels of colour sensitivity. Two separate sets of 10 fair and dark shade digit prosthesis samples were each fabricated with a stepped increase in colour difference (deltaE) against the baseline hand prosthesis. Ninety individuals with normal colour vision scores were selected as colour assessors. The colour difference of each prosthesis in the two series was evaluated visually against the baseline by the assessors, using defined scores. The thresholds for perceptible and acceptable colour difference determined in this study were deltaE= 0.8 and deltaE= 1.8 for the fair series and deltaE = 1.3 and deltaE = 2.6 for the dark series, respectively. The acceptable threshold values differed from the perceptible threshold values by deltaE= 1.0 for the fair-shade samples and deltaE= 1.3 for the dark-shade samples. This study demonstrated that subjective visual assessment is positively correlated with deltaE values computed from colorimetric measurements for both fair and dark-shade silicone samples (p<0.001). This results shows that human subjects with normal colour vision are capable of accurately assessing colour differences. These observations emphasize the importance of subjective feedback on colour by the patient, provided the latter has perfect colour-tested vision. The study also showed that human subjects were less sensitive to perceived colour differences in darker-shade than fairer-shade samples (p < 0.001). This finding seems relevant in a clinical setting involving a multi-ethnic patient population.

Artificial Limbs↗
PubMed1995

Elderly drivers and simulated visual impairment.

BACKGROUND: The effect of simulated visual impairment on the driving performance of elderly subjects and the relation between changes in driving performance and vision were investigated. METHODS: Vision was impaired by goggles simulating the effects of cataracts, binocular visual field restriction, and monocularity. Driving was assessed on a road circuit free of other vehicles. Visual performance was measured using the Humphrey Field Analyser (HFA), the Useful Field of View (UFOV), and the Pelli-Robson chart. RESULTS: The simulated visual impairment significantly decreased driving performance, even though all drivers satisfied the legal visual requirements for driving. Significant correlations between driving performance and the UFOV and Pelli-Robson chart were found.

Aged↗
PubMed2006

Vigabatrin retinopathy in an Irish cohort: lack of correlation with dose.

PURPOSE: The anticonvulsant vigabatrin (VGB) causes irreversible visual-field constriction in 19-92% of patients. It is unclear whether this correlates with dosing, and the natural history of the retinopathy remains obscure. We conducted a retrospective analysis of patients receiving long-term VGB to examine whether toxicity is related to the daily dose, duration of therapy, or cumulative dose. METHODS: Information from 93 patients taking long-term, stable VGB therapy was analyzed. We recorded data on patient demographics, VGB dosing, and all visual-field assessments. We used the mean redial degrees (MRD) from the right eye to compare the amount of constriction with the dose of VGB. RESULTS: The mean number of assessments was two (range, 1-6). Of patients having more than one assessment (n = 65), the mean follow-up time was 2.4 years (range, 0.7-5.6 years); in 52.7%, visual-field constriction developed. Male and female patients were affected equally. We found no correlation between the average MRD and either the maximum dose of VGB taken, the duration of exposure, or the cumulative dose. The shortest exposure time to development of constriction was 1.1 years. All patients with normal fields on initial assessment continued to have normal fields on follow-up. Most patients who had evidence of constriction on initial assessment and remained taking VGB showed no progression on follow-up. One patient had a substantial recovery of vision after discontinuation of VGB. CONCLUSIONS: Development of visual constriction in patients receiving prolonged, standard doses of VGB does not depend on the daily dose, duration of exposure, or cumulative dose. Other contributing factors were not identified. Our data suggest that field defects may develop within the first few years of therapy and possibly remain stable thereafter.

Adult↗
PubMed1991

Optic nerve sheath decompression for nonarteritic ischemic optic neuropathy improves multiple visual function measurements.

Optic nerve sheath decompression was performed in seven patients with nonarteritic anterior ischemic optic neuropathy. Visual function was evaluated by measurement of visual acuity with standardized Early Treatment Diabetic Retinopathy Study charts, color vision testing, quantitation of relative afferent pupillary defects with neutral-density filters, and Goldmann and Humphrey perimetry. Visual acuity improved markedly in all patients (at least doubling of the visual angle); the peripheral visual field expanded by at least 20 degrees (as measured by Goldmann perimetry) in six patients. Three patients also experienced marked improvement in color vision, relative afferent pupillary defect, and foveal sensitivity. Our experience supports the possible beneficial effect of optic nerve sheath decompression in patients with nonarteritic anterior ischemic optic neuropathy.

Aged↗
PubMed2003

Clinical features of the retinopathy, globe enlarged (rge) chick phenotype.

The purpose of the study reported here was to characterize the clinical aspects of the autosomal recessive retinopathy, globe enlarged (rge) phenotype in chicks (Gallus gallus). Rge/rge, rge/+ and +/+ chicks were studied from hatch to 336 days of age by general clinical examination, post-mortem examination, vision testing with an optokinetic device, ophthalmoscopy, biomicroscopy, tonometry, central corneal pachymetry, a-mode ultrasonography, infrared photoretinoscopy and photokeratometry. Additionally, preliminary electroretinographic and histopathologic investigations were performed. There is a variable degree of vision loss in rge/rge chicks at 1 day of age with further chicks losing vision over the next few weeks until all chicks become functionally blind by 30 days of age (although some optokinetic responses remain in some of the rge/rge chicks). Over the first few weeks of life rge/rge chicks develop thicker corneas with a larger radius, hyperopia, shallower anterior chambers and enlarged globes both radially and axially, compared to controls. A preliminary ERG study showed that 1 day old rge/rge chicks have an elevated response threshold, a lower amplitude a-wave with a markedly shallow leading slope, a lack of both oscillatory responses and c-waves and, at brighter flashes, an increased b-wave amplitude. Light microscopy revealed no gross retinal abnormalities in young chicks to account for the blindness. A thinning of all retinal layers developed in parallel with globe enlargement. The rge defect is a unique progressive retinal dystrophy that results in a severe visual deficit, abnormal electroretinographic waveforms, and secondary globe enlargement.

Analysis of Variance↗