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At least 955 records · Page 53Linked to original sources
PubMed2000

Hereditary retinal dystrophies and choroidal neovascularization.

BACKGROUND: Choroidal neovascularization infrequently occurs in patients affected by hereditary retinal dystrophies. METHODS: We studied eight patients suffering from different hereditary retinal dystrophies (Best's disease, reticular dystrophy, butterfly-shaped dystrophy, gyrate atrophy, and retinitis pigmentosa) who developed choroidal neovascularization. All patients underwent complete ophthalmic evaluation, electrophysiology, colour vision testing, and fluorescein angiography. In some patients, ICG video-angiography was also performed. Laser treatment was carried out in only one patient. RESULTS: The mean duration of follow-up was 41.7 months (range 6-148 months). At CNV diagnosis, the mean VA was 0.23 (range 0.02-0.6). At the last follow-up, mean VA was 0.34 (range HM to 0.9). At the last follow-up, fluorescein angiography showed a focal, atrophic scar in seven eyes, a fibrotic membrane in two eyes and a still active membrane in two cases. CONCLUSION: We emphasize the relatively favourable visual prognosis in patients suffering from inherited retinal dystrophies complicated with choroidal neovascularization. Therapeutic approaches other than laser treatment could be attempted in these patients.

Adult↗
PubMed1991

The visual and driving performance of monocular and binocular heavy-duty truck drivers.

This study compared the performance of 40 monocular and 40 binocular tractor-trailer drivers on measures of both visual and driving performance. On the visual measures, the mononuclear drivers were significantly deficient in contrast sensitivity, visual acuity under low illumination and glare, and binocular depth perception. They were not significantly deficient in static or dynamic visual acuity, visual field of individual eyes, or glare recovery. Driving measures of visual search, lane keeping, clearance judgment, gap judgment, hazard detection, and information recognition showed no differences between monocular and binocular drivers. Monocular drives were poorer than binocular drivers only in sign reading distance in both daytime and nighttime driving. This decrement correlated significantly with the binocular depth perception measure. There were large individual differences within each group for most of the visual and driving performance measures. It was concluded that monocular drivers have some significant reductions in selected visual capabilities and in certain driving functions dependent on these abilities, compared with binocular drivers. However, monocular drivers are not significantly worse than binocular drivers in the safety of most day-to-day driving functions. Implications of these findings and the large individual differences within each group are discussed.

Adult↗
PubMed1966

Use of water-drinking tonography in mass screening for glaucoma.

The results of mass screening for glaucoma of workers in a factory in Chiba Prefecture, Japan, are reported. At the first-stage examination, tonometry was performed with standardized Schiøtz tonometers on 1,527 subjects (3,054 eyes) with no ocular symptoms. When the tension was 5.0/5.5 gm or higher, the patient was regarded as a preliminary suspect and a detailed ophthalmologic examination was recommended. The second-stage examination, in the University Clinic included campimetry, vision tests, water-drinking tonography, tonometry with applanation and Schiøtz tonometers, funduscopy and gonioscopy. Of the 239 (381 eyes) preliminary suspects, 79 came to the Clinic for the second-stage examination. Water-drinking tonography, done on 104 eyes with tension of greater than 5.0/5.5 gm, revealed that 48 had a Po/C ratio greater than 100, which strongly suggests the presence of glaucoma. In water-drinking tonography, a Po/C ratio greater than 100 was noted in about 34% of 58 eyes with a tension of 4.25/5.5-5.0/5.5 gm, suggesting that the index for separating glaucoma suspects from normals could be brought down to the level of 5.0/5.5 gm. The over-all percentage of glaucoma cases found was 1.3%. The efficacy of water-drinking tonography in mass screening for glaucoma has been discussed.

Adolescent↗
PubMed1993

A dissociation of shape discrimination and figure-ground perception in a patient with normal acuity.

We report the case of a 21-year-old man who sustained brain damage due to anoxia. His visual acuity was normal and his colour perception was adequate if not completely normal. However, his shape discrimination was so impaired that he had great difficulty distinguishing a square from an oblong or a large square from a smaller square. At the same time, other aspects of his shape perception were remarkably intact. His performance on a shape detection task was good. He had no difficulty on tests of figure-ground (boundary) segmentation and his perception of subjective and illusory contours appeared to be normal. S.M.K.'s performance on a number of tasks is compared with that of a patient (F.G.P.) previously reported who showed the opposite pattern of deficit (Kartsounis and Warrington, Neuropsychologia 29, 969-980, 1991). This evidence of a double dissociation between two components of shape perception is discussed in the context of a neurophysiological model of the organization of the visual system.

Adult↗
PubMed1989

Subchronic dosing of macaques with 2,5-hexanedione causes long-lasting motor dysfunction but reversible visual loss.

Visual sensitivity and neurological status were monitored in four female macaque monkeys dosed orally with 2.5-hexanedione (0.64 mM/kg, 5 days per week) for 15 or 17 weeks. The first sign of toxicity was intention tremor seen after 3 months of dosing. This was followed, a week later, by a moderate decrease in visual contrast sensitivity, which returned to baseline 6 to 11 weeks after the end of dosing. Acuity and flicker resolution were not disrupted. A progressive general weakness ensued for 5 to 7 weeks after dosing had ended. Some slow recovery was seen, although the animals remained severely disabled 20 weeks after dosing was discontinued. Pathologic changes were examined 3 weeks (one monkey) and 20 weeks (three monkeys) after dosing. Soon after the end of dosing, axonal swellings were present throughout the distal optic tracts, peripheral nerves, and long tracts of the spinal cord. Twenty weeks after dosing, there was no indication of degeneration in the retinocortical pathway. Peripheral nerves showed widespread axonal loss, residual ongoing degeneration, and only slight regeneration. Axon loss and gliosis were evident in distal dorsal columns, and to a lesser extent, dorsal spinocerebellar and corticospinal tracts. These effects of 2,5-hexanedione on the macaque differ from those found previously for two other axonotoxic compounds, acrylamide monomer and carbon disulfide, which caused marked permanent degeneration that was most prominent in the visual system.

Animals↗
PubMed1982

Interocular transfer of the motion aftereffect in strabismus.

The interocular transfer of the motion aftereffect (MAE) was measured in three groups of strabismic subjects (six with monofixation, nine with alternation, four with anomalous retinal correspondence) and compared with a group of four normal subjects. The duration of the MAE was measured using sinusoidal gratings of 0.5 c/deg subtending a visual angle of 8. Contrary to previous findings, a substantial amount of MAE transfer was found in some stereoblind individuals with strabismus. The mean amount of transfer for each group was found to correlate with binocularity; the order of decreasing transfer being: normal, monofixation, alternation, and anomalous retinal correspondence (ARC). This reduction in transfer which accompanied the loss of binocularity was asymmetric, that is, right-left transfer did not equal left-right transfer. The amount of asymmetry was found to correlate inversely with the amount of transfer. The direction in which the greatest transfer occurred did not correlate with visual acuity. These data substantiate the overall poor binocularity in subjects with ARC, and the relatively good binocularity of subjects with monofixation. Furthermore, the substantial amount of transfer found in subjects with alternating strabismus may be a measure of potentially achievable binocularity.

Adolescent↗
PubMed1982

Adult levels of meridional anisotropy and contrast threshold in 5-year olds.

This study, using a forced-choice technique, shows that 5-yr-old children have greater sensitivity for vertical and horizontal sinusoidal gratings than for obliques. Contrast thresholds for all orientations were similar to those of adults as was the magnitude of the meridional anisotropy. These results suggest that meridional anisotropy does not develop over an extended period of childhood as was previously reported (Mayer, 1977). Reasons for the discrepancy between the two studies are discussed.

Adult↗