Don’t Fire Until You See the Whites of Their Eyes

What do people fear the most? It’s often said that giving a speech tops the list. But a recent survey shows that it’s losing one’s sight. Today, with an aging population, an increasing number of people face the ultimate fear—a condition called age-related macular degeneration (AMD) that destroys vision and can even lead to blindness.

“Don’t fire until you see the whites of their eyes” was a command once given to British soldiers. But if these soldiers had AMD, they wouldn’t have fired a single shot. AMD destroys the macula, a tiny spot in the retina responsible for central vision.

AMD is the leading cause of blindness for those over 50 years of age and affects more people than cataracts and glaucoma combined. It affects close to 300,000 Canadians, more Canadians than those who have breast cancer, prostate cancer, Parkinson’s disease, and Alzheimer’s disease combined. Close to 30,000 will develop this condition in 2009, and by age 75, one in three North Americans has early signs of AMD.

The effects of vision loss are devastating because it robs patients of their independence. The decline in everyday functioning due to vision loss may lead to depression and to anxiety and despondence in a caregiver, often a family member.

There are two types of macular degeneration. The common dry type of AMD affects 90 percent of patients. Vision is decreased due to the appearance of small yellow deposits that cause thinning and dryness of the macula, a tiny spot that allows you to look someone straight in the eye.

The wet type, the most serious, strikes 10 percent of those with this disease. In this case abnormal blood vessels grow under the macula. This growth pushes the macula from its normal position, distorting and eventually destroying central vision.

Without central vision, we cannot recognize faces, see fine detail, or drive a car. In the early stages of wet AMD, patients may not notice any significant difference in their vision, particularly if only one eye is affected. But eventually straight lines appear wavy or crooked, decreasing central vision, making the central spot become blurry.

Patients may also complain of decreased color vision, increased sensitivity to light, or a dark spot in the center of the vision surrounded by a distorted image. Or there can be a combination of all these troubles.

The diagnosis of wet AMD can mean severe central vision loss and possibly even blindness in a matter of weeks or months.

We can’t control aging, but we can decrease the risk of developing AMD. For instance, make sure that your diet is rich in lutein, a powerful antioxidant that helps to protect the eye from visible and ultraviolet light. Lutein is found in fruits and dark leafy vegetables. The recommended daily allowance of lutein is 6 milligrams.

There is no known cause for AMD. The strongest risk factor is age. And there’s an increased chance if there’s a family history of this disease or there has been an excessive exposure to sunlight, smoking, a diet low in antioxidants, or if you’re a woman.

High doses of vitamins A, C, E, and zinc also help to prevent macular degeneration and reduce the risk of further vision loss for those already diagnosed with this disease.

Medical consumers need to recognize the signs of AMD early enough to seek treatment before AMD severely compromises their ability to function independently. So if you start to see that your straight vision is becoming abnormal, be sure to consult your doctor.

Dr. Gifford-Jones is a medical journalist with a private medical practice in Toronto.
Dr. Gifford-Jones’s Web site

Last Updated
Dec 1, 2008