Structural and functional correlates in color vision deficiency.

PURPOSE: The aim of this study is to assess the photoreceptor integrity, using spectral domain optical coherence tomography (SD-OCT), and to measure the retinal sensitivity of patients with congenital red-green color vision deficiency (CVD).
METHODS: In all, 14 eyes from 7 patients with congenital red-green CVD (diagnosed by Farnsworth Munsell 100 hue test), and 14 eyes from 7 control subjects were examined by SD-OCT and microperimetry. Radial scans (7-mm) were taken of the macula. The center of the fovea was defined. The thickness of different retinal layers, at the foveal center, and at multiple defined points along all six radial scans, was measured. The median readings were compared between the two groups using Mann-Whitney U-test.
RESULTS: SD-OCT demonstrated normal total retinal thickness, normal thickness of the photoreceptor layer, normal thickness of the outer nuclear layer, normal vertical thickness of the outer segments (OSs), and normal vertical thickness of the inner segments. OS horizontal diameter was less in left eye in cases with CVD when compared with controls. The mean retinal and foveal sensitivity was similar between cases and controls.
CONCLUSIONS: In subjects with congenital red-green CVD, there are no discernible anatomical abnormalities seen on SD-OCT in various retinal layers, except for a narrower foveal pit. However, further studies with larger sample size are required.