Understanding Geographic Atrophy

Dr. David Maberley, MD, FRCSC, Ophthalmologist

Duration: 3 minutes and 3 seconds

Geographic atrophy is an advanced form of age related macular degeneration that affects the central vision and progresses typically quite slowly over many, many years. Geographic atrophy is a breakdown in the pigment layer underneath the retina that supports it and nourishes it. When that layer dies, the overlying retinal cells, the rods and cones, die as well.

Geographic atrophy usually affects the central part of vision called the macula and is responsible for significant vision loss that is currently is not repairable. In contrast to the wet form of macular degeneration, which is the other advanced form of macular degeneration, the wet form progresses very quickly. Blood vessels grow under the retina, often with sudden onset, and vision loss occurs over a period of a few months.

Treatments for the wet macular degeneration are aimed at stopping the blood vessels growth that drives the damage to the retina. With geographic atrophy, we need to ultimately try to replace these missing layers of the outer retina. Stem cell treatments or transplants might be an option in the future but currently we don't have any ways of effectively reversing these areas of damage.

Geographic atrophy tends to present with central vision loss that progresses slowly over many months, often years, and is often unnoticed by patients. The reason it's unnoticed is we don't tend to register it until it actually enters the central part of our vision. And at that point, there is quite advanced or high risk of losing functional vision.

Geographic atrophy can be diagnosed using photographs and special types of light that are shone into the eye to illuminate the pigment layer under the retina and also can be diagnosed with the same type of laser imaging called OCT that we use for most other retinal conditions. It can also be diagnosed using regular examinations of the back of the eye and typically, it's most commonly picked up by an eye care provider during routine examination of the retina.

Geographic atrophy is difficult to prevent. It tends to be linked to genetic risk factors, as well as potentially other AMD risk factors such as increasing age, sunlight exposure, obesity, cardiovascular disease, high cholesterol, smoking and some forms of diet.

There are new treatments that are currently coming to market that may slow the progression of geographic atrophy, but currently, we still have no way of reversing the damage that occurs with this form of age related macular degeneration.

Presenter: Dr. David Maberley, Ophthalmologist, Ottawa, ON

Local Practitioners: Ophthalmologist