Age Related Macular Degeneration:

Age related macular degeneration (AMD) is the most common form of macular degeneration and is the leading cause of legal blindness in North America affecting almost 30% of people over the age of 75. This disease results from a slow deterioration in the function of the pigment cell layer under the retina leading to the development of abnormal waste products termed drusen and pigment cell loss. These changes occur over many years and are generally gradual in nature. AMD is currently diagnosed through a clinical examination, no special testing is required, at a routine eye examination. There is no therapy for the dry form of the disease presently, the knowledge that a patient has this condition is important to establish an effective monitoring strategy.

Although the risk factors for macular degeneration are numerous, the most important factors are age, genetics and a history of smoking. Patients with dry macular degeneration or a strong family history should be strongly encouraged to discontinue smoking as this is certainly the most important modifiable risk factor. AMD is not past on through a single gene but rather several genes which contribute to an increased risk and although no specific gene therapy is present at this time genetic testing has recently become available to determine an individual personal level of risk.

For the dry form of the disease current recommendations are that patients with moderate dry AMD findings be started on a daily supplement including vitamins A, C, and E as well as Zinc and Lutein. A large well designed study showed a 25 % risk reduction through inpatients through the use of these vitamins and several products are commercially available without a prescription.

For the wet form of macular degeneration, in which an abnormal vessel grows beneath the vessel resulting in bleeding and leakage of fluid ultimately leading to a scar in the central portion in the patients’ vision, several drugs have recently become available and are actively in clinical use and many more are in future development. Although all of these medications are designed to limit visual loss and cannot be used until the wet form of the disease has developed, they are limited in the degree of visual recovery which they can achieve. The current gold standard treatment available to patients in Canada is Lucentis, a drug injected into the eye on a monthly basis to block the main growth factor in this process. Lucentis has shown exceptional results at limiting further visual loss and provides for a significant visual gain in approximately 1/3 of patients. Ongoing clinical trials are evaluating other agents as well as combination therapy to look at ways of improving visual benefits for our patients and limiting the number of treatments needed.