Electrophysiology

The retina, like other tissues of the brain and nervous system, is electrically active (meaning it produces an electrical current). In the case of the eye, light passes through the cornea and lens and is absorbed by the retina, which generates an electrical signal. This is transmitted through the cable of the eye called the optic nerve. From there, it arrives at the back of the head (a region called the occipital lobe) where visual perception occurs. We literally see from the back of our head! Electrophysiological (EP) testing of the retina/macula is a noninvasive technique that measures the electrical activity of the eye. The pattern electroretinogram (PERG) is an effective and quantitative diagnostic tool to measure function, especially in patients with macular diseases such as age-related macular degeneration, diabetic macular disease, various inherited retinal/macular diseases, and optic nerve diseases. The PERG test can help distinguish between macular and optic nerve disease. Comprehensive Retina Consultants has very significant experience in the understanding and use of retinal EP testing.

Another type of EP testing is the visual evoked potential (VEP) that can specifically detect optic nerve function including glaucoma, optic atrophy (e.g., ischemic optic atrophy), papilledema, and optic neuritis associated with multiple sclerosis (MS). The third type of EP testing that Comprehensive Retina Consultants utilizes is the multi-focal electroretinogram (mfERG). This test is specifically used to diagnose and monitor acquired and hereditary macular diseases, along with potential drug toxicities associated with plaquenil, chloroquine, tamoxifen (taxo), and other drugs. mfERG is the most sensitive and objective test for macular function. It can be used with a test like OCT or qAF to monitor both the structure and function of the macula while a patient is being treated.