If you are like many Canadians, you probably don’t know a lot about AMD. Even if you already have it, you may not fully understand what is going on inside your eyes. As its name suggests, AMD is a disease linked to age. Specifically, people over age fifty are affected. In spite of the fact that AMD is the leading cause of severe vision loss and legal blindness in people over 50 in the Western world, it’s still relatively unknown. Currently, about one third of people 55-74 years of age and almost 40% of those over the age of 75 have some form of AMD.

AMD is a chronic, age-related, degenerative disease of the macula. The macula is a very small and specialized area in the centre of the retina. The macula allows you to see fine details directly in front of you such as the words in a book or images on television. So, while the entire retina lets you see that there is a book in front of you, the macula lets you see what is written in the book.

There are two types of AMD - dry AMD and wet AMD. Generally, dry AMD progresses quite slowly and is usually less severe than the wet type. Both types damage the macula and both can take away your central vision. Early detection and intervention are important in preventing or delaying vision loss. In the case of dry AMD, unless it is detected in a routine eye exam, you may not even realize that you have the disease until it reaches an advanced stage. This is due to its usually slow and painless progression over a period of years and the ability of one eye to compensate for any weakness in the other. However, wet AMD can cause severe and irreversible central blindness, often within months. Therefore, it is important to visit your eye doctor regularly, especially if you determine that you’re at risk.

Risk Factors
There are a number of risk factors, both in and out of your control, that can put you at increased risk for developing AMD. Some of the known or suspected risk factors that we cannot control are:
  • Age: Risk increases with advancing age (from 8.5% for people 43-54 years of age to 36.8% for people over 75)
  • Family History: Up to 3 times greater risk within families (parents and siblings)
  • Gender: Females are more susceptible
The following are risk factors in your control:
  • Smoking
  • Diet: A diet low in antioxidant vitamins and minerals is a significant risk factor
  • Excessive sunlight exposure
  • High blood pressure
  • Excessive weight/obesity
Obviously you can’t change everything that puts you at risk, but lifestyle changes can certainly reduce your risk.
What is Dry AMD?
Most of the time, AMD will begin as the less severe dry type and for approximately 80% of people, it will remain as such. Dry AMD can develop in one or both eyes. The early stages of dry AMD begin with the appearance of drusen. Drusen are small white or yellowish deposits that begin to accumulate in of the deepest layers of the retina – you will not be aware that these deposits are forming. The build-up begins to disrupt the layers above it – eventually damaging the layer of photoreceptor cells (cells that receive visual images from the lens) resulting in “blank” or blind spots in your central visual field. As the disease continues to progress, the likelihood of it turning into the more severe wet AMD increases significantly. Your eye doctor will work with you to develop a plan to slow the progression of the disease. Regular visits to your eye doctor are critical for early detection and preservation of your vision. Since dry AMD develops quite slowly, it can affect the vision in your eyes without you being aware of it. Your eyes and brain are very good at compensating for the weakness.

Treatment of dry AMD is focused on monitoring and slowing the progression of the disease. Your eye doctor will monitor your progress at specific intervals with timely office visits – you can also be told to monitor your vision at home with an Amsler Grid (useful and simple tool to monitor your central vision). Modifications in lifestyle issues may also help slow the progression of the disease and specific high-dose vitamin therapy has been shown to delay the progression of dry AMD and preserve vision. Your eye doctor will discuss all of these with you.
Wet AMD is named because of the involvement of blood in the deepest layers of the retina. New and abnormal blood vessels begin to grow beneath the retina and push their way up through it (like tree roots or weeds growing up through cracks in the pavement). This process eventually results in “blank” or blind spots in the central visual field. This eventually results in the growth of scar tissue which can cause severe and permanent vision loss. Although wet AMD can occur spontaneously, it is usually preceded by dry AMD which make regular check-ups especially important.

Your vision is precious – do whatever is in your control to hold on to it:
  • Visit your eye doctor regularly
  • Take specific ocular vitamin supplements if recommended by your eye doctor
  • If you notice a change in your vision, contact your eye doctor immediately
  • Stop smoking – ask for help if you need it
  • Improve your diet- include fresh fruits and vegetables (especially dark green leafy vegetables like spinach)
  • Maintain a healthy body weight
  • Avoid excessive exposure to direct sunlight- wear sunglasses and wide-brimmed hats to protect your eyes from UV light
  • Keep high blood pressure under control
  • Be proactive about vision rehabilitation and the use of visual aids 
If you have any inquiries regarding the content of this article please contact your Smith Drugs & Apothecary pharmacist or your personal eye care professional
Norm Corriveau, B.Sc.Phm
The AREDS Formulation and Age-Related Macular Degeneration, Govt. Summary, 2011
Age-Related Eye Disease Study, National Eye Institute, 2011
A guide to understanding AMD, Novartis, 2011
Self Care & Wellness: Issues in Eye Care, Canadian HealthcareNetwork.ca, Nov. 2012