In clinical and in vitro conditions, the effect of intravitreously injected silicone oil upon the electroretinogram and electrooculogram was investigated. The recorded potentials were lower in the eyes with silicone oil compared to those in which the retinas were reattached without silicone. Retinal changes, caused by the previously existing detachment and the operations already performed, are discussed as possible factors responsible for lower values of the recorded potentials. No arguments could be found in favor of silicone retinopathy.