If there was a simple test you could take that would tell you your risk of losing vision from eye disease, would you take it?
This is one of the questions being asked about new genetic testing for age-related macular degeneration (AMD), the leading cause of blindness in Canada. While not everyone goes blind from AMD, some degree of vision loss is likely. The risk of getting AMD increases with age, from only 2% in middle-age to almost 30% for those over the age of 75.
Now there are tests available that can help predict one’s risk for developing vision loss from AMD. These tests are designed to pick up certain genetic markers – small changes in DNA – that are seen in AMD. The most common one used in Canada involves taking a saliva sample which is then analyzed for the key genetic markers.
The argument for genetic testing for AMD is due to the fact that this eye disease has both genetic AND environmental risk factors. Knowing the risk for this condition may prompt someone to make the lifestyle changes necessary to reduce their risk as much as possible. For example, one of the biggest lifestyle risk factors for AMD is smoking. Smokers have a 2-3 X increased risk of vision loss from AMD overall, however, having a certain genetic marker called CFH Y402H SNP and being a smoker increases that risk by 34 times!
We also know that diets rich in dark green leafy vegetables and fruits help reduce the overall risk for getting AMD. Some of the new research may soon help your eye doctor tailor your specific diet and vitamin intake to reduce your chances of vision loss from AMD. Lastly, knowing whether someone is genetically at risk for AMD will help your eye doctor decide how often to see that person for checkups. Early detection of more advanced forms of AMD is critical, and timely treatment can prevent or delay vision loss considerably.
On the other hand, knowing that one is at high risk for this condition may affect quality of life by causing a great deal of anxiety. Since there is no outright cure for AMD, some argue that genetic testing may result in a lot of unnecessary stress about future vision loss.
Our position at Mountain View Optometry is that the choice of whether or not to undergo genetic testing for AMD is entirely a personal one. We can definitely provide lots of general information about lifestyle adjustments to reduce your risk, even without the knowledge about the genetic markers you may have.
Come and speak to our eye doctors during your next appointment so we can discuss your specific risk factors for AMD and other conditions.
-Dr. Tom Wilk