Patterns of color vision impairment found in ETDRS patients

Researchers have identified 13 distinct patterns of color vision impairment in patients with diabetic retinopathy in a large-scale study.

Franca B. Barton, MS, and colleagues examined the results of the Farnsworth-Munsell 100-hue test, which was administered before treatment in each eye of 2,701 patients enrolled in the Early Treatment Diabetic Retinopathy Study (ETDRS).

Statistical cluster analysis uncovered 13 distinct patterns. Pattern A, which was seen in 1,366 (51%) of the eyes, showed unimpaired hue discrimination. Most patients with this pattern were relatively young with little or no macular edema. Pattern B, seen in 262 (10%) showed generalized impairment of hue discrimination with no main axis defect. Three C patterns (C1, C2, C3), seen in 698 eyes (26%), showed increasing severity of the yellow-blue diabetic retinopathy defect, associated with increasing mean age and increasing macular edema severity. Two D patterns (D1, D2) seen in 164 eyes (6%), were similar to the C patterns but showed a stronger yellow-blue defect. Three E patterns (E1, E2, E3) were seen in 38 eyes (2%), affecting men predominantly. These eyes exhibited the expected pattern for congenital protan defect. Patterns F, G and H were seen in 153 eyes (about 6%), showing distinct patterns of one-sided axes.

The study is published in the July issue of American Journal of Ophthalmology.