Abstract

The assessment of a sensitivity loss in patients with retinal disease is often performed in the presence of a background. Marré and Marré¹, for example, have devised a technique based on Wald's version of Stiles' two-color threshold technique to measure the relative loss in three "basic cone mechanisms", each mechanism is isolated with a single chromatic background. Other investigators have argued for a selective sensitivity loss of a blue cone mechanism or a chromatic mechanism based upon data also collected at one or two adapting field intensities. The implicit assumption is that sensitivity loss of a particular cone mechanism is independent of the level of adaptation. This paper has two goals. First, we review evidence indicating that sensitivity loss is not independent of the level of adaptation in patients with RP, and we propose that models of sensitivity loss must incorporate a model of adaptation². Second, we apply the model of adaptation proposed by Hood and Greenstein³ to assess whether the tvi data from RP patients support the hypothesis that RP primarily affects the receptors.

© 1988 Optical Society of America