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At least 919 records · Page 51Linked to original sources

Cone dysfunction in a subgroup of patients with autosomal dominant cerebellar ataxia.

Four patients with autosomal dominant cerebellar ataxia and retinal degeneration underwent neurologic and ophthalmologic examinations and computer-assessed corneal electroretinography. Previous reports described progressive panretinal degeneration initially involving the cones and subsequently spreading to the rods. By contrast, all our patients displayed evidence of selective dysfunction of the cone system in one or two successive electroretinograms, irrespective of their age or duration of visual symptoms. Color vision testing, funduscopy, and fluorescein angiography suggested a cone dystrophy. Within the period of observation only one patient showed progression of cone dysfunction. In patients with hereditary ataxias, quantitative electroretinography provides an objective and sometimes early indication of retinal degeneration and helps to characterize it.

Adult↗

The clinical profile of optic neuritis. Experience of the Optic Neuritis Treatment Trial. Optic Neuritis Study Group.

The baseline characteristics of 448 eligible patients entered into the Optic Neuritis Treatment Trial are described in an effort to summarize the clinical profile of acute optic neuritis. A total of 77.2% of the patients were women. Mean age was 31.8 years. Pain accompanied the visual loss in 92.2% of cases. The optic disc appeared swollen in 35.3% of the patients and normal in 64.7%. A wide variety of visual field defects were present. Abnormalities in asymptomatic fellow eyes were noted, particularly on perimetry. Magnetic resonance imaging showed changes consistent with demyelination of the brain in 48.7% of the patients. Magnetic resonance imaging, serologic studies (such as the antinuclear antibody test and the fluorescent treponemal antibody absorption test), chest roentgenography, and lumbar puncture were of limited utility in defining a cause for visual loss other than optic neuritis associated with demyelinative disease.

Adolescent↗

A family with X-linked optic atrophy linked to the OPA2 locus Xp11.4-Xp11.2.

Autosomal dominant optic atrophy (ADOA) is the most common inherited optic atrophy. Clinical features of ADOA include a slowly progressive bilateral loss of visual acuity, constriction of peripheral visual fields, central scotomas, and color vision abnormalities. Although ADOA is the most commonly inherited optic atrophy, autosomal recessive, X-linked, mitochondrial, and sporadic forms have also been reported. Four families with X-linked optic atrophy (XLOA) were previously described. One family was subsequently linked to Xp11.4-Xp11.2 (OPA2). This investigation studied one multi-generation family with an apparently X-linked form of optic atrophy and compared their clinical characteristics with those of the previously described families, and determined whether this family was linked to the same genetic locus. Fifteen individuals in a three-generation Idaho family underwent complete eye examination, color vision testing, automated perimetry, and fundus photography. Polymorphic markers were used to genotype each individual and to determine linkage. Visual acuities ranged from 20/30 to 20/100. All affected subjects had significant optic nerve pallor. Obligate female carriers were clinically unaffected. Preliminary linkage analysis (LOD score = 1.8) revealed that the disease gene localized to the OPA2 locus on Xp11.4-Xp11.2. Four forms of inherited optic neuropathy, ADOA, autosomal recessive optic atrophy (Costeff Syndrome), Leber hereditary optic neuropathy, and Charcot-Marie-Tooth disease with optic atrophy, are associated with mitochondrial dysfunction. Future identification of the XLOA gene will reveal whether this form of optic atrophy is also associated with a mitochondrial defect. Identification of the XLOA gene will advance our understanding of the inherited optic neuropathies and perhaps suggest treatments for these diseases. An improved understanding of inherited optic neuropathies may in turn advance our understanding of acquired optic nerve diseases, such as glaucoma and ischemic optic neuropathy.

Chromosomes, Human, X↗

Effect of levodopa treatment on contrast sensitivity in Parkinson's disease.

We studied contrast sensitivity function in 10 parkinsonian patients before and after levodopa treatment. Pretreatment contrast sensitivity function was abnormal in 16 of the 20 eyes. After treatment, only high-frequency loss was observed in 6 eyes. All other types of deficit disappeared under treatment. These changes of contrast sensitivity function following treatment suggest that dopamine is a functional transmitter in the visual pathways.

Aged↗

State motor vehicle laws and older drivers.

After teenage males, elderly individuals have the highest per capita motor vehicle fatality rate in the United States. Surprisingly, there has been only limited work examining the effect of state motor vehicle laws on older driver fatalities. This paper uses state-level data from the 1985-2000 Fatality Analysis Reporting System to examine the effects of changes in state laws dealing with license renewal, seatbelt use, speed limits, and driving while intoxicated on fatalities among drivers and others aged 65 and over. Negative binomial regressions are estimated using alternatively state and year fixed effects, or age and year fixed effects. In-person license renewal reduced fatalities among the oldest drivers, but vision tests, road tests and the length of the license renewal cycle generally did not. In terms of policies that apply to all drivers, seatbelt laws, particularly with primary enforcement, were generally the only policies that reduced older driver fatalities. These results are noteworthy because a number of policies that have been effective towards increasing younger driver safety are not relevant for older drivers, implying that policymakers must think broadly about using state laws to improve older driver safety.

Accidents, Traffic↗

Ophthalmological aspects of chronic CS2 intoxication.

As a pilot study preliminary to a large scale survey on chronic CS2 toxicity 30 workers of a viscose rayon industry in Belgium have been examined. Twenty of them were working in the xanthation spinning department where chronic CS2 intoxication is more likely to occur and ten controls were chosen form the supposedly safe bleaching division. Ophthalmological evaluation included visual fields, coulour vision testing, fluoro-angiography, ERG and EOG. In both groups fundus anomalies, abnormal EOG's and subnormal or supranormal ERG's were found. The fundus anomalies consisted either of discrete pigmentary changes in the posterior pole or microvascular retinal lesions.

Adult↗

Electrophysiologic testing techniques for children.

This practical article for clinical electrophysiologists discusses the evaluation of infant and child patients' visual systems using electroretinographic (ERG), electrooculographic (EOG), and visually evoked potential (VEP) techniques. These techniques not only help to secure specific diagnoses, but by systematic assessment of function along the visual pathways can also localize dysfunction underlying visual deficits of pediatric patients. Among children, development as well as disease can affect electrophysiological parameters. Therefore diagnosis of normal or abnormal depends critically on an adequate description of normal responses for age. Procedures that the authors have found feasible, reliable, and valid are summarized. Standardization of pediatric testing appears to be an important next step. The power of ERG, EOG and VEP recordings to demonstrate the neurophysiological basis for pediatric visual impairment is predicted to stimulate further research in this area.

Adult↗

Main types of bull's eye maculopathy. Functional classification.

Bull's eye maculopathy is a non-specific reaction of the posterior pole of the eye. The concentric dispersion of pigment occurs when the disease interferes with the function of the retinal pigment epithelium. The site of the primary process may be the bipolar cell layer, the receptor cell layer or the retinal pigment epithelium. By means of electrodiagnostic techniques and color vision testing the site of the primary lesion as a rule can be retraced.

Adolescent↗

Towards a classification of visual impairment.

For the rehabilitation of people with impaired vision, it is essential to have adequate (preferably quantitative) information about their residual visual functions. Special attention is given to the extra information provided by the results of measurement of the contrast sensitivity, especially in combination with the results of other measurements, such as the visual field, the amount of intraocular straylight and the visual acuity. The value of the contrast sensitivity function as a predictor of the extent of dysfunctioning in the visual activities of everyday life, such as outdoor vision, reading and recognition of faces, will be discussed. As far as this is concerned, a comparison is made between the value of visual acuity and contrast sensitivity as measures of the extent of vision and visual dysfunctioning.

Contrast Sensitivity↗

Contrast sensitivity and pattern visual evoked potential in patients with glaucoma.

Contrast sensitivity and pattern visual evoked potential (VEP) were measured in cases of ocular hypertension and primary open-angle glaucoma at various stages. The visual field of each eye was examined quantitatively and the retinal nerve fiber layer and optic disc were precisely assessed with magnified stereoscope fundus photography. This study revealed that contrast sensitivity of the eyes with glaucoma was within the normal range in the very early stage of the disease. As optic nerve damage advanced, high- or low-frequency loss developed. Further optic nerve damage produced a level type of loss. Pattern VEPs also showed increasing abnormalities as glaucomatous optic nerve damage progressed. Measurements of contrast sensitivity and pattern VEP were found not to be as sensitive as quantified precise visual field measurement or color stereoscopic fundus photography for detection of minor optic nerve damage in cases of early glaucoma. These methods may be useful, however, as an objective and subjective monitor of progression of optic nerve damage in glaucoma.

Adolescent↗

Alternating hyperphoria. Dissociated vertical deviation (DVD) 'occlusion hyperphoria'.

Alternating hyperphoria (synonyms: dissociated vertical deviation (DVD) or occlusion hyperphoria) and variants like 'unilateral patching hyperphoria' ('periodic vertical squint') and monocular vertical nystagmus, which may arise after strabismus operations or loss of the function of one of the eyes, have dynamic properties which differ from those of the vertical vergences or fusional movements in normal binocular vision. Alternating hyperphoria is the result of an early intense disturbance of binocular vision, leading to the absence of vertical fusional vergence or the detection of disparity necessary for this. Vertical disparity vergence is essentially a stabilizing and adaptive system.

Adolescent↗

Illumination research as part of a visual assessment of visually impaired individuals.

In this paper we describe a method for the preliminary assessment of the illumination needs of partially sighted individuals. The method is based on determining the smallest readable lettersize under different levels of illumination. Half of the partially sighted in our population had a performance that was dependent upon the level of illumination. At the same time, most of those for whom no improvement in performance was found, did express a preference for a certain level of illumination. Therefore, there remain discrepancies between the objectively determined optimal level and the preference for a certain level. We conclude that the current method is a useful but insufficient method of determining the illumination needs of partially sighted individuals.

Adolescent↗

Natural versus haploscopic stereopsis.

Natural stereopsis is better with a large interpupillary distance (IPD). With haploscopic devices, depth perception is better with a small IPD. This apparently unknown fact has been trigonometrically calculated and experimentally shown by enlarging and diminishing the IPD in 20 subjects.

Adolescent↗