Ms Ellie Bowditch, Dr Yu Xiang George Kong Jamie E Craig
Purpose: Colour vision testing is a routine part of the assessment of optic neuropathy, and is often used to distinguish glaucomatous optic neuropathy from other types. However, the nature of colour vision defects in glaucoma is poorly-understood. In this study we aimed to assess the nature and preva- lence of acquired colour vision defects in a tertiary glaucoma population using the desaturated (L?Anthony) D-15 arrangement test.
Method: This prospective, cross-sectional study recruited 110 subjects with established glaucoma, seven with compressive optic neuropathy (CON), and 15 normal controls from the Royal Victorian Eye and Ear Hospital. Colour vision testing with the desaturated D-15 was conducted following screen- ing for congenital dyschromatism using Ishihara plates.
Results: A signiftcant difference in colour vision test scores was identifted across all glaucoma subtypes (POAG & OHT, PACG, secondary glaucoma) and CON compared to normal controls, with both glau- coma and compressive optic neuropathy participants producing more erroneous colour vision test scores (p<0.001 for each group). Glaucoma and CON were not distinguishable by the severity of acquired dys- chromatopsia alone. However, proportionally more subjects with CON produced a mixed-type defect (both B-Y and R-G) compared to subjects with glau- coma that tended to have a pure B-Y defect. Conclusion: This study revealed that subjects with glaucoma are more likely to have a pure B-Y defect compared to subjects with CON and normal con- trols. The desaturated D-15 is a simple and more speciftc tool for assessing colour vision defects in patients with glaucoma.