We performed a pilot study of electroretinographic monitoring of retinal function during eye surgery performed with local anesthesia. A contact lens with a built-in light-emitting diode was sterilized and used as both a stimulus source and a recording electrode for 30-Hz flicker electroretinograms. Each recording required 7 seconds, during which the operating light (but not the room light) was switched off. Electroretinograms recorded during surgery on 10 patients with minimal retinal abnormality were evaluated for the effects of light adaptation caused by regular exposure to an operating light source or operating microscope. The fluctuations of the amplitude and peak time were small, indicating that this technique can be used to monitor retinal function during eye surgery. Some results during retinal and vitreous surgeries are shown.