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Abstract #10394 Published in IGR 6-1

Simultaneous comparison of relative damage to chromatic pathways in ocular hypertension and glaucoma: correlation with clinical measures

Castelo-Branco M; Faria P; Forjaz V; Kozak LR; Azevedo H
Investigative Ophthalmology and Visual Science 2004; 45: 499-505


PURPOSE: To use a new methodological approach, based on luminance noise, to assess without bias the relative damage of blue-yellow and red-green pathways in ocular hypertension and glaucoma, and to correlate the measurements obtained with clinical markers of disease progression. METHODS: A psychophysical procedure modified from the Cambridge color test was used to assess color discrimination in three groups: patients with primary open-angle glaucoma (n = 51 eyes), patients with ocular hypertension (n = 95 eyes), and control subjects (n = 46 eyes). Viewing conditions were such that the function of the macula was being tested, using a discrimination task under noisy conditions. Confusion vectors and parameters obtained from discrimination ellipses were correlated with perimetric and clinical data taken from the same groups. RESULTS: The lengths of the major axis of chromatic discrimination ellipses and all confusion vectors were significantly different between the groups. These measurements followed a significant gradient of worsening performance from the control to hypertensive and glaucoma groups, which was steeper for the tritan axis. There was a significant global positive correlation between test parameters and cup-to-disc ratio and a significant negative correlation with the perimetric mean deviation index. Ellipse length in patients with ocular hypertension correlated significantly with the duration of their hypertensive state. CONCLUSIONS: This psychophysical test can detect visual dysfunction in a significant subset of patients with long-term hypertension with preserved visual fields. Macular function is damaged earlier than previously believed, in both the blue-yellow and red-green pathways.

Dr. M. Castelo-Branco, Center for Ophthalmology, Department of Biophysics, Instituto Biomedico para a Investigacao da Luz e Imagem, Faculty of Medicine, Coimbra, Portugal. mcbranco@ibili.uc.pt


Classification:

6.6.3 Special methods (e.g. color, contrast, SWAP etc.) (Part of: 6 Clinical examination methods > 6.6 Visual field examination and other visual function tests)



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