Electroretinogram (ERG) to test the function of visual cells
During the ERG test, you will wear eye patches and sit in a dark room for 30 minutes. Then the researcher will tape electrodes to your forehead (this is painless, as are all uses of electrodes in these tests) and remove the eye patches. The surfaces of your eyes will be numbed with eye drops, and contact lenses will be placed on your eyes. You will look inside a hollow, dark globe and see a series of light flashes. Then a light will be turned on inside the globe, and more flashes will appear. The contact lenses sense small electrical signals generated by the retina when the light flashes.
