Fig. 4. Photostress test. A. The retina is bleached with bright light as the patient occludes the other eye. B. The recovery phase is timed. C. The second eye is exposed to light. D. Photo-stress recovery times in macular and optic nerve disease. The dotted line represents 50 seconds, the upper limit of normal for 99% of control eyes. CSR, central serous retinopathy, RPE, retinal pigment epithelium; SMD, senile macular degeneration. (From Glaser JS, Savino PJ, Sumers KD: The photostress recovery test: A practical adjunct in the clinical assessment of visual function. Am J Ophthalmol 83:255, 1977)