Dexamethasone protection against photochemical retinal injury

Photochemical retinal injury was produced in the foveomacula of the rhesus monkey using the light from an indirect ophthalmoscope. The eyes were examined by both light and electron microscopy. Damage consisted of vacuolization of the retinal pigment epithelium and neurosensory retinal layers. Pretreatment with subcutaneous injection of dexamethasone for 16 weeks prior to light exposure markedly decreased damage to the retinal pigment epithelium, but had no apparent effect on damage to the neurosensory retina in eyes examined 18 hours after exposure. The mechanism responsible for this protective effect is unknown.