What is an Electroretinography?

An electroretinography, or ERG for short, is a method of testing used at Marano Eye Care that measure the electrical response of the light-sensitive cells in the eyes. These cells, called cones and rods, form the back portion of the eye, called the retina. Both the cones and rods have a very specific purpose within the retina. The cones are responsible for providing the eye’s sensitivity to color, while the rods are much more sensitive to light. The ERG test will be performed if initial diagnosis points towards retinal disorders like retinitis pigmentosa, macular degeneration, retinoblastoma, retinal separation, or cone-rod dystrophy. ERG testing may also be used to determine the patients need for retinal surgery and other eye surgeries, like the removal of cataracts.

How to Prepare for an ERG

To prepare for electroretinography testing, the patient will be asked to sit or lie in a comfortable position, and the eyes will be dilated, as well as numbed with the use of anesthetic drops. Our team will then put into place a device called a retractor, which is used to hold the eyelids open for the duration of the test. A small electrode, about the size of a contact lense, is placed over each eye to measure the electrical response from the retina. As the ERG testing begins, the patient will be asked to watch a flashing light, first with normal lighting in the room, then in a darkened room.

Data collected via the electrodes on each eye will be recorded on an attached monitor, where the electrical responses, known as A waves and B waves, can be analyzed by the Marano Eye Care staff.