Effect of alcohol and light on the retinal pigment epithelium of normal subjects and patients with retinal dystrophies

Background-Light absorbed by photoreceptors causes oscillations in the volt age across the retinal pigment epithelium (RPE). This is the basis of the c linical test, electro-oculography (EOG). We have previously shown that alco hol causes a sequence of voltage changes which are so precisely the same as those caused by light that they must be produced by the same RPE machinery . There is good evidence that alcohol produces its effect by a direct actio n on the RPE. Consequently, in diseases associated with loss of photorecept ors, alcohol should continue to produce the voltage changes of the EOG unle ss secondary changes have occurred in the RPE. Methods-The alcohol response in patients with retinitis pigmentosa (RP) was investigated using EGG. Results-In no patient with RP was there any alcohol rise. Conclusion-In patients with RP secondary abnormalities of function of the R PE must occur.