Retinal Diseases

Diagnosis

The diagnosis of a retinal disease is usually made based on a thorough eye exam by an ophthalmologist. An ophthalmoscope allows the doctor to view the inside of the eyes in three dimensions. The ophthalmologist looks for presence of abnormalities anywhere in the eye. Additional tests may be done to determine the location and extent of the disease.

Amsler Grid Test

The physician may use a printed grid to test clarity of central vision. The doctor will ask if the lines of the grid seem faded, broken or distorted, and will take note of where the distortion occurs on the grid. By evaluating the location of the distortion, the physician will better understand the extent of retinal damage caused by disease.

Optical Coherence Tomography (OCT)

Similar in principle to ultrasonography, OCT relies on light waves slicing through tissue layers in the back of the eye. They produce a "backscattering" that converts into high-resolution, cross-sectional images of the retina, macula and optic nerve. Particularly useful in investigating abnormal tissue, OCT allows Mayo clinicians to diagnose diseases such as epiretinal membranes, macular holes and macular edema (swelling). With this new medical imaging technology, clinicians have another painless, precise diagnostic tool.

Fluorescein Angiography

To get more information about a suspected retinal disease, the doctor may use fluorescein angiography to identify leaking blood vessels. First, the doctor injects dye into a vein in the patient's arm. As the dye circulates through the bloodstream and eventually to the eye, the blood vessels in the retina stand out as bright yellow when observed with a special blue light. A camera takes flash photographs of the eye every few seconds for several minutes. The images help identify the blood vessels, new abnormal blood vessels and subtle pigmentation changes in the back of the eye.

Indocyanine Green Angiography (ICGA)

Another type of angiography of the vessels in the eye is ICG. ICG is a dye that lights up when exposed to infrared light. Infrared light is used to take pictures of the back of the eye visualizing retinal blood vessels, and the deeper, harder to see choroidal blood vessels.

Ultrasound

An ophthalmologist can usually find evidence of retinal disease with the ophthalmoscope, but occasionally blood or other problems in the eye prevents a clear view of the retina. In these cases, the doctor may use ultrasound, a painless test that uses sound waves to get a precise picture of the retina. Ultrasound is also used to measure the size of growths in the back of the eye.