THE ENHANCED S-CONE SYNDROME - AN ANALYSIS OF RECEPTORAL AND POST-RECEPTORAL CHANGES

The purpose of the study was to test the hypothesis that the retinae o f patients with enhanced S cone syndrome (ESCS) have more S cones than the normal retina and these cones have replaced some of the L and M c ones, Standard and spectral full-field electroretinograms, measurement s of L, M, and S cone system sensitivities and S cone acuity were obta ined from three patients with ESCS. The results were qualitatively con sistent with the presence of more S cones and more S cone ganglion cel ls, To test this hypothesis further, a model of the receptoral and pos t-receptoral components of the S cone system was used in conjunction w ith psychophysical measurements of S cone system sensitivity under fla shed and steady-state adaptation conditions. Within the context of the model, the data were consistent with an increase in the number of S c ones and S - (L + M) ganglion cells and with a decrease in the total L + M cone input to each S - (L + M) ganglion cell. Copyright (C) 1996 Elsevier Science Ltd.