The right eyes of anesthetized, 10-week-old albino rats were exposed to constant photon fluxes at 6 wavelengths for 6 hrs. The left eye of each animal was patched during the exposure and was used as control. Histologic examination of retinal sections disclosed a region in the superior retina that was more damaged than were other areas. Attempting to ascertain an action spectrum by measuring ONL lost in this "sensitive" region failed. However, it was shown that, when ONL thickness was integrated over the entire retinal sections, a rhodopsin action-spectrum emerged. It was concluded that (1) retinal light damage in the albino rat under these conditions was rhodopsin mediated, and (2) proper assessment of the extent of damage could only be made by some method that integrates over the entire retinal section.