In my last blog about ARMD (age related macular degeneration) I went over the bare basics of what macular degeneration is. There’s a lot more to macular degeneration than what I discussed and many people are confused about what exactly is going on. In this blog I want to go over one form of macular degeneration: dry macular degeneration.

Dry ARMD is the most common form. It makes up about 90% of all ARMD. The good news though is that it only accounts for about 10% of serious vision loss. That’s not to say that people with dry ARMD don’t suffer a loss of central vision and have trouble seeing, it just means that they are still able to function reasonably well. But what IS dry ARMD. What does it mean? For that we have to dive into a little bit of anatomy and physiology (I promise it's not too hard).

You might remember from science class that our retina has a bunch of different layers. The important ones for ARMD are the photoreceptors (better known as the rods and cones) that detect light and the retinal pigmented epithelial layer that keeps food and oxygen going where it should (these layers were not named to be short… that’s why we call that one the RPE). So what goes wrong in someone with ARMD? It all starts with little yellow flecks called drusen.

The yellow flecks in the middle are drusen. You don't want these.

Drusen are thought to be clumps of waste product from the cells of the retina that haven’t been cleared out by your blood vessels. Some more recent research suggests they come from ongoing inflammation. Regardless of where they come from they mean trouble. Drusen on their own do not mean that someone has ARMD. In fact the great majority of people with drusen don’t have ARMD at all! Drusen are a huge risk factor for developing the disease though and shouldn’t be ignored.

Like many things in the eye the exact way that drusen cause damage to the RPE isn’t fully understood but the most commonly accepted reason is that drusen decrease the amount of food and oxygen that can get to the RPE. Unsurprisingly this isn’t good for the RPE and it dies. Since the RPE’s job is to feed the photoreceptors in the eye when the RPE goes the photoreceptors in the same area die off too. This degeneration of the RPE and photoreceptors is what we call dry macular degeneration or if you want to be really fancy and impress your friends the official term for this is geographic atrophy.

In some cases though, these drusen do not lead to degeneration of the RPE and photoreceptors. In some cases they cause wet macular degeneration. We'll learn more about wet ARMD in another blog.

If you want to read more feel free to check out the following links or as always you can contact us on Twitter, Facebook, Google +, via our website or phone us at (403) 474-6744.

CNIB - ARMD

Doctors of Optometry Canada - ARMD

AMD.org - Dry ARMD

Mayo Clinic - Dry ARMD

Age Related Macular Degeneration (ARMD) is the most common cause of blindness in Canada, affecting more than one million Canadians. That is more people than breast cancer, prostate cancer, Alzheimer’s and Parkinson’s combined! As you may have guessed from the name, it primarily affects people over the age of 50. In its earliest stages ARMD has no symptoms and can only be detected during a regular eye examination. In the later stages of ARMD, central vision is distorted or completely lost, leaving a central blindspot.

This is what things can look like in advanced ARMD.

So what if you’re under 50? What then? Doesn’t that mean that you have nothing to worry about? Well, sort of. ARMD doesn’t typically strike people when they’re young in the same way that skin cancer doesn’t typically affect younger people. That means that someone who is 30 is almost definitely not going to show any signs of ARMD. However, just like you can wear sunscreen to decrease your risk of skin cancer there are things that you can do to decrease your risk of getting ARMD. And just like sun protection, the younger you protect your eyes, the lower your risk.

Alright, so maybe now I’ve convinced you that prevention and detection are important. What can you do? Lifestyle plays a huge role in ARMD. People who smoke have a greatly increased risk of developing ARMD. Poor eating habits and a lack of cardiovascular activity also increase your risk. Exposure to UV light is also harmful and increases your risk. There also factors that you cannot change such as age, gender, family history and ethnicity that increase your risk. As you age your risk increases, women are more commonly affected than men, people with lighter coloured eyes or skin colours have a greater risk and if someone in your family has ARMD you have a higher risk (good ol’ genetics). All that said, if you wear sunglasses, avoid smoking or second hand smoke and live a healthy lifestyle you can greatly decrease your risk of developing ARMD. A healthy diet is often a challenge even for the most health conscious of people and there are specific eye vitamins on the market both for people with risk factors for ARMD and for people who currently have ARMD. Speak with your optometrist about which of those vitamins is right for you.

Since there are no symptoms even if you’re doing everything right it’s very important to see your optometrist regularly. Even though ARMD cannot be cured, early intervention and detection can help slow down how rapidly the disease progresses and keep your vision from worsening. Technology such as an OCT scan, which is offered at our clinic, can help to detect ARMD at its earliest stages.If you have any questions feel free to call or email us. You can also reach us on Twitter, Facebook, Google + or via our website. For more information feel free to explore these other sites.

CNIB - Macular Degeneration

Doctors of Optometry Canada - Macular Degeneration