Age-Related Macular Degeneration (AMD): A Guide for Ontario Patients

Age-related macular degeneration (AMD) affects approximately 2.5 million Canadians and is the leading cause of vision loss in those over 50. It does not cause complete blindness — peripheral vision is preserved — but it eliminates the central vision used for reading, driving, and recognizing faces.

The macula

The macula is a small, specialized area at the centre of the retina, approximately 5mm in diameter. It contains the highest concentration of cone photoreceptors and is responsible for fine detail, colour vision, and all tasks requiring central vision. AMD damages this region progressively.

Dry AMD

Dry AMD is characterized by the accumulation of drusen — yellowish protein and lipid deposits under the retina — and the gradual atrophy of retinal pigment epithelium (RPE) cells. It progresses through three stages:

• Early AMD — small drusen, no vision symptoms
• Intermediate AMD — larger drusen, possible mild vision changes
• Advanced dry AMD (geographic atrophy) — large areas of RPE and photoreceptor death; central vision loss

Dry AMD progresses slowly over years. It accounts for about 90% of AMD cases but causes the majority of advanced vision loss only in its geographic atrophy stage.

Wet AMD

Wet AMD occurs when abnormal new blood vessels (choroidal neovascularization) grow under the retina. These vessels are fragile and leak fluid or blood, damaging photoreceptors rapidly. Wet AMD can cause severe central vision loss within weeks if untreated.

Warning signs that require same-day evaluation:

• Sudden distortion of straight lines
• New central blur or dark spot
• Rapid change in vision

Use the Amsler grid — a grid of horizontal and vertical lines with a central dot — to monitor for distortion at home. Your optometrist can provide one.

Risk factors

• Age — risk increases significantly after 55
• Smoking — the single most modifiable risk factor; smokers have 2–4x the risk
• Family history — strong genetic component
• Cardiovascular disease, high blood pressure, obesity
• Lighter iris colour (blue or green eyes)
• Prolonged UV exposure without protection

AREDS2 supplementation

For intermediate AMD or advanced AMD in one eye, the AREDS2 formula (Age-Related Eye Disease Study 2) has been shown to reduce progression risk by approximately 25%:

• Vitamin C 500mg
• Vitamin E 400 IU
• Lutein 10mg
• Zeaxanthin 2mg
• Zinc 80mg
• Copper 2mg

These supplements are available over the counter and are not covered by OHIP, but are widely available at Ontario pharmacies. They are not recommended for early AMD or as a general preventive measure in those without AMD.

Anti-VEGF treatment for wet AMD

Anti-VEGF injections (aflibercept/Eylea, ranibizumab/Lucentis, faricimab/Vabysmo) are administered directly into the eye by a retinal specialist. They block the growth factor responsible for abnormal vessel growth and leakage. Most patients require injections every 4–16 weeks, often indefinitely. These treatments are covered by the Ontario Drug Benefit (ODB) program for eligible patients.

Monitoring at home

Anyone diagnosed with AMD should monitor daily with an Amsler grid and report any new distortion immediately. Do not wait for your next scheduled appointment — wet AMD requires urgent treatment.