Many of our patients are on drugs which reduce intraocular pressure. We do this not so much because the patient has glaucoma, as because by reducing the intraocular pressure we can often improve the function of the optic nerve. Some of the drugs actually increase the blood flow through the optic nerve into the macula through the ciliary circulation. Gonioscopy allows us to make sure that the channels are open for fluid to get out of the eye. This is performed with a contact lens. That is the only way that the channels in what is called the angle of the eye can be viewed. We can tell whether they are open or whether drugs are an appropriate way to help these patients. This is often performed on your visit prior to seeing the doctor. It takes but a few minutes to perform the test.