PERIPHERAL COLOR CONTRAST - A NEW SCREENING-TEST FOR PREGLAUCOMATOUS VISUAL-LOSS

• Tipo: Artigo em Revista Científica Internacional
• Data: 1991

Autores

YU, TC (Autor) Outra; Falcão-Reis F (Autor) FMUP; SPILEERS, W (Autor) Outra; ARDEN, GB (Autor) Outra

Revista

Título: Investigative ophthalmology & visual science

Vol. 32

Páginas: 2779-2789

ISSN: 0146-0404

Indexação

ISI Web of Knowledge - 54 Citações

Scopus - 54 Citações

Outras Informações

ID Authenticus: P-001-QGC

Abstract (EN): A new test of peripheral color contrast is described. A high-definition color monitor driven by a personal computer with a graphics interface card displays an annulus subtending 25-degrees at the eye. The color contrast between the annulus and the background can be varied. Forty-five degrees of the annulus is randomly removed in one of four quadrants. Patients are asked to identify the position of the gap while fixating a central spot. The minimum color contrast between annulus and background at which the identification is possible is between 13-16% for the protan, deuteran, and tritan axis in normal subjects. This threshold value changes little with age, refractive error, or pupillary aperture, and test-retest variability is low. Testing one eye takes only 1-2 min. The test was applied to ocular-hypertensive and glaucomatous patients. All patients with glaucoma had thresholds greater than two standard deviations (SD) above the normal mean. In addition, 97% of glaucoma patients had thresholds greater than four SDs, and 95% had thresholds more than five SDs above the normal mean. Most patients with ocular hypertension and clinical signs indicating a low or medium risk of conversion to glaucoma had thresholds under the upper limit of normal. High-risk patients with ocular hypertension fell into two groups. One approximated to normal; the other had elevated thresholds, which in many cases were more than four SDs above the normal mean. The epidemiologic consequences of this test are discussed.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 11