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Leading causes of blindness

Three million Canadian seniors, or 82 per cent of the population aged 65 and older reported vision problems in 2003, according to data from the Canadian Community Health Survey.

Three million Canadian seniors, or 82 per cent of the population aged 65 and older reported vision problems in 2003, according to data from the Canadian Community Health Survey.

While it is common for many people to experience various eye and vision problems as they get older, the incidence of vision impairments which are unable to be remedied with eyeglasses increases with age.

Three leading causes of blindness, which are particularly relevant to seniors, are cataracts, glaucoma, and macular degeneration.


A cataract is the clouding in the lens of the eye, impeding the passage of light, which leads to vision loss. This painless condition usually occurs with aging, but there are risk factors which accelerate or foster development, such as prolonged exposure to ultraviolet (UV) light, tobacco use, physical trauma and diabetes.

Diagnosis and assessment of cataracts are made by your eye doctor, usually with a comprehensive dilated fundus (retina) exam. Treatment involves removal of the cataract, and placement of an artificial lens implant. Cataract removal is one of the most common and safest surgeries per-formed today, but as always, discuss any risks with your eye care professional. An updated eye glass prescription can sometimes delay the need for cataract surgery.

To help slow the progression of cataracts, your optometrist or ophthalmologist may recommend sunglasses with good UV protection and reducing risk factors such as alcohol consumption, smoking, managing diabetes, and corticosteroid use. Some also believe that a diet high in vitamins, antioxidants, and carotenoids (contained in some fruits and leafy green vegetables) may help protect against cataracts.


Glaucoma is an eye disease affecting the optic nerve. According to the Glaucoma Research Foundation, half of people with the disease are unaware that they have it. Glaucomatous vision loss usually begins peripherally and progresses centrally, so a surprising amount of vision may be compromised before such loss is even noticed. Vision loss associate with glaucoma is permanent and irreversible.

Risk factors for glaucoma include elevated eye pressure, family history, age, ethnicity, suspicious optic nerve appearance, and various medical conditions. Your eye doctor can determine if you have glaucoma using a variety of diagnostic tools, including optic nerve analysis, measurements of eye pressure, peripheral vision or visual field tests, and measurements of corneal thickness. Compliance of regular eye examinations is the best thing you can do to improve your chances of early detection of glaucoma.

Because of the irreversible nature of vision loss related with glaucoma, it is imperative to catch glaucoma in its early states.

Technological advances allow us to detect glaucoma earlier, even before vision loss begins. Once diagnosed, treatment involves procedures to reduce eye pressure and protect the optic nerve. Depending on type and severity of glaucoma, those treatments can include medications and/or surgery.

Macular Degeneration

Age related macular degeneration (AMD) is a condition in which damage occurs to the macula, the part of the retina responsible for sharp central vision. There are two forms of AMD - the "dry" form and the "wet" form.

Dry AMD is more common, but wet AMD is more severe, causing irreversible and rapid vision loss due to abnormal blood vessel growth and leakage inside the eye. Treatment of wet AMD involves the injection of medication in the eye to prevent such blood vessels from growing.

While no medical or surgical treatment is available for dry AMD, the role of nutritional intervention in slowing or preventing its progression continues to be explored.

A landmark study for AMD known as the Age-Related Eye Disease Study (AREDS) showed that high amounts of certain antioxidants and zinc can reduce the risk of advanced AMD by as much as 25 per cent for those with intermediate macular degeneration in both eyes or advanced macular degeneration in one eye.

The study did not show that such antioxidants and zinc prevented the development of macular degeneration, and did not have any bearing on the development or progression of cataracts. Still, many eye care professionals advocate the use of nutritional supplements (vitamins A, C and E, and certain other minerals) to help manage or lower risk of AMD, and most do not oppose their patients taking supplements or foods containing these antioxidants.

Phase two of the AREDS study is presently in its late stages, and seeks to evaluate whether similar protective benefits may be associated with other nutrients such as omega-3 fatty acids, lutein and zeaxanthin.

By a retina exam, your eye doctor is able to detect early signs of AMD before symptoms occur. Risk factors for AMD include aging, smoking, lighter skin and eye color, obesity, and heredity and family history. No conclusive evidence has shown that sun exposure contributes to the risk of AMD, although some eye care providers may recommend protection from UV light. Your eye doctor may also send you home with an Amsler grid, a chart of straight black lines, to monitor development to wet AMD; someone progressing to wet AMD may see some of the lines as wavy or blurred around darkened spots.

Dr. John Kim was Assistant Clinical Professor at State University of New York School of Optometry for 10 years and is now the primary optometrist at a local optometry clinic.