RESUMO
Recent studies have described abnormalities of visual evoked potentials and pattern electroretinography in diabetics without retinopathy. The visual contrast sensitivity, determined by psychophysical tests, has proved to be abnormal in diabetic patients with and without clinical retinopathy. In this study we evaluated contrast sensitivity function using both electrophysiologic and psychophysical methods. The objective assessment of functional visual contrast sensitivity was superior to psychophysical evaluation in the detection of contrast sensitivity alterations. No relationships were found between contrast sensitivity dysfunction and abnormalities of pattern electroretinography or fluorescein angiography. Our data suggest that functional visual deficits might precede background retinopathy and that the involvement of foveal function is early and very frequent in diabetic patients, even if they have normal visual acuity.
Assuntos
Retinopatia Diabética/diagnóstico , Potenciais Evocados Visuais , Percepção de Forma , Reconhecimento Visual de Modelos , Adolescente , Adulto , Angiografia , Criança , Eletrorretinografia , Feminino , Fluoresceínas , Humanos , MasculinoRESUMO
A consecutive series of patients with normal activity and a diagnosis of multiple sclerosis (10 male and 31 female) underwent extensive ophthalmological examination including visual evoked potentials (VEPs) and a new test of contrast sensitivity, which is described in detail. Seventy three per cent of patients had abnormal contrast sensitivity and 83% had abnormal VEPs. There was no association between abnormalities of the two types, but patients who had impaired contrast sensitivity and normal VEPs were younger than those whose contrast sensitivity was normal but whose VEPs were not. The test of contrast sensitivity (which took less than 5 minutes to administer) was the only examination to reveal visual abnormalities in all nine patients with a history of optic neuritis, and would be a useful supplementary test in the examination of patients with suspected multiple sclerosis.
Assuntos
Esclerose Múltipla/complicações , Transtornos da Visão/diagnóstico , Testes Visuais/métodos , Adolescente , Adulto , Fatores Etários , Potenciais Evocados Visuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/fisiopatologia , Transtornos da Visão/etiologia , Transtornos da Visão/fisiopatologia , Percepção VisualRESUMO
Optic pathways are frequently involved in Multiple Sclerosis (MS). However, in some cases the involvement is asymptomatic or gives rise to only slight visual disturbances without alterations of visual acuity or of clinically evident visual field defects. In these cases several diagnostic tests permit an objective evaluation of the visual dysfunction. The aim of this study is to compare the value of contrast sensitivity test (CST), pattern reversal visual evoked potential (VEP), ophthalmoscopy, Goldmann perimetry in 45 MS patients with normal visual acuity. Examination of contrast sensitivity was carried out with a simple two-alternative forced choice test estimating the spatial frequency of 4 cycles/degree. The VEP was performed with a pattern reversal checkerboard at a spatial frequency of 1 and 2 cycles/degree. Fundus examination was abnormal in 12 patients; visual field defects were detected in 16 patients. 32 patients (71.1%) had abnormal CST in one or both eyes. VEP for the 30' checks was abnormal in 32 cases (71.1%) and that for the 15' checks in 36 cases (80.0%). All but 4 patients (91.2%) had one or more abnormal tests. All patients with abnormal perimetry and/or fundus examination had also CST and/or VEP altered. It is apparent that CST and VEP reveal a significant proportion of abnormalities in the visual system that have not been revealed by routine neuroophthalmological examination.
Assuntos
Esclerose Múltipla/diagnóstico , Testes Visuais/métodos , Adolescente , Adulto , Potenciais Evocados Visuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/fisiopatologia , Oftalmoscopia , Reconhecimento Visual de Modelos , Estimulação Luminosa , Valor Preditivo dos Testes , Testes de Campo VisualRESUMO
A simple technique is described for assessing the sensitivity of the human visual system to gratings at threshold contrast. The technique has advantages for clinical use in that it is (1) inexpensive, (2) quick to administer, (3) portable, and (4) relatively free from bias. Forty-two diabetic patients and 84 normal controls have been tested. Fifteen diabetic patients (6/20 with retinopathy and 9/22 without) had test scores more than two standard deviations below the norm for age-matched controls.
