Dyschromatopsia in diabetes mellitus and its relation to metabolic control.

In 102 insulin-dependent diabetic patients without retinopathy and with visual acuity 20/20, the Farnsworth-Munsell 100-Hue test was performed, and glycosylated hemoglobin (GlHb) levels were determined. In 70% of the patients, a dyschromatopsia in the yellow-blue axis (tritanopia) was found. No correlation existed between duration of diabetes and tritanopia. On the other hand, the degree of this visual defect was positively correlated with GlHb levels. Thus, dyschromatopsia might be associated with poor metabolic control. It is suggested that dyschromatopsia is a consequence of hypoxia at the neuroepithelial level. The high levels of GlHb could be a contributory cause of hypoxia by reduction of both oxygen release capacity and erythrocyte deformability.