Understanding how AMD develops

Understanding how AMD develops Dr. Bernard Hurley, MD, FRCPC, Vitreoretinal Surgeon

Duration: 3:27

AMD is an aging change that affects the retina and the back of the eye. It typically begins to develop after the age of 50. The initial things we see in the back of the eye are little dark spots. We call them aging spots, but we use the term Drusen in ophthalmology.

These changes are more common in people who have a mix of risk factors. Most of the risk factors are genetic and are related to inflammation that occurs in the back of the eye. There are, however, other factors such as cardiovascular disease, obesity, diet and exposure to sun that may also affect the development and progression of dry AMD.

In the early stages of dry AMD there are no visual symptoms and you would not know you have AMD unless you have your eyes examined by an eye care provider. Over time, the drying and Drusen progress.

Visual symptoms will start to develop if you have the following: • The formation of larger drusen • The development of areas where the pigment cells in the back of the eye die • If there is blood vessel growth under the retina in the back of the eye.

The latter of those suggests wet AMD is developing.

If you think of the back of the eye like a freshly paved sidewalk where over time the sidewalk starts to crack and crumble, this is like dry macular degeneration that we see in an aging eye. These cracks can occur slowly and might take decades to develop. You can then start to get new blood vessels that try and grow through these cracks, for example, sometimes a tree, or even grass might start to grow up through one of the cracks in the sidewalk and cause damage very quickly. The tree and grass are metaphors for blood vessels that can grow through the cracks in the macula. These new blood vessels are damaging to the eye and indicates the development of wet macular degeneration where blood vessels start to grow up underneath the retina. This can occur very quickly and lead to vision loss and damage.

We typically don't know how to repave the sidewalk but there are medications that can work kind of like weed killer in the back of the eye and can stop the growth of these abnormal blood vessels in the back of the eye.

If you have anyone in your family who have a history of dry AMD or vision loss and you are concerned about your eye health, please make sure to see your local optometrist or ophthalmologist for proper screening.

Presenter: Dr. Bernard Hurley, Ophthalmologist, Ottawa, ON

Local Practitioners: Ophthalmologist