Macular Degeneration

Diagnosis

At Mayo Clinic, diagnosis of macular degeneration begins with a thorough eye exam using the latest diagnostic technology. Following diagnosis, the doctor may perform additional tests to determine the location and extent of the disease.

Drusen (yellow spots) deposits in and around the macula

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Distorted view of the Amsler grid due to macular degeneration

Fluorescein angiography image showing blood vessel leakage in the retina

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Eye exam

During the eye exam, the doctor looks for abnormalities in the macula, such as yellow deposits called drusen. In addition, the appearance of the macula is important to sharp central vision. If the pigmentation is mottled or uneven, instead of its normal even reddish color, macular degeneration may be the cause.

Amsler grid test

As a part of the eye examination, the doctor may evaluate vision using a printed grid. If macular degeneration is present, the lines of the grid may seem faded, broken or distorted. By noting where the distortion occurs (usually near the center of the grid), the doctor can better determine the location and extent of macular damage.

Fluorescein angiography

After diagnosis, the doctor may perform a fluorescein angiography test to determine the extent of damage from macular degeneration. First, the doctor injects fluorescein dye into a vein in the patient's arm. As the dye circulates through the bloodstream and eventually to the eye, a camera takes flash photographs of the eye every few seconds for several minutes. The photos help identify pigmentation changes, blood circulation patterns and abnormal blood vessels.

Indocyanine green angiography (ICGA)

ICGA is another type of angiography of the eye vessels that sometimes provides additional useful information for the doctor to review. 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 to visualize retinal blood vessels, and the deeper, harder to see choroidal blood vessels.

Optical coherence tomography image of the retina

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Optical coherence tomography (OCT)

OCT is an imaging method that uses ultrasound technology to provide detailed, cross-section images of the retina and its underlying layers. OCT is useful for checking retinal thickness and thinness because it is capable of clearly displaying well-defined tissue boundaries in high resolution. Bright colors are added to the image to highlight specific areas of the retina and to determine how much light they reflect.

Genetic testing

In nearly half of patients with age-related macular degeneration, a gene mutation occurs that is responsible for a protein associated with immune system function called Complement Factor H. This is one of the most important discoveries in macular degeneration to date. Mayo Clinic was the first medical center to have routine testing for this gene available to patients.