Correlation of chromatic, spatial, and temporal sensitivity in optic nerve disease

Spearman rank-order correlations (R) were made between the color-mixture threshold, spatial contrast sensitivity, and flicker sensitivity measurements of 38 patients with a variety of optic nerve disorders. Patients had to satisfy the following criteria: greater than 0.5 log unit loss of chromatic or achromatic sensitivity (compared to age-matched normals), central fixation, no congenital color defects, and no ocular media abnormalities. The results of the analysis show a significant correlation between selective losses of high spatial frequency sensitivity (relative to low) and selective losses of red/green and blue/yellow sensitivities [R = -0.680 (P less than 0.001) and R = -0.439 (P less than 0.01), respectively]. A mild correlation was found between selective spatial and selective temporal losses [r = -0.399 (P less than 0.05)] (ie, low temporal frequency losses correlate with high spatial frequency losses and vice versa). A stronger correlation was found between selective red/green and selective blue/yellow sensitivity losses [R = 0.657 (P less than 0.001)]. No correlation was found between selective temporal losses and selective chromatic losses. These findings can be explained in terms of differential losses of three types of fibers: (1) fibers that are particularly sensitive to red/green color, high spatial and low temporal frequencies; (2) fibers signalling blue/yellow color; and (3) fibers that are relatively sensitive to high temporal frequencies and low spatial frequencies.