Glaucoma: Sight stealer

For most people, their greatest health fear – next to contracting cancer – is going blind. Glaucoma is the second leading cause of blindness, but the frightening fact is that half the people in Canada who have it don’t even know it. And the longer their condition is left undetected, the greater the damage to their eyesight.

Dr. Graham Trope, Chair of the Department of Ophthalmology at the University of Toronto, says close to 200,000 Canadians have been diagnosed with glaucoma. Five thousand are registered as blind.

Glaucoma can strike anyone – mostly older people, but sometimes even children. Few know about it because those who have it don’t discuss it. But slowly people are beginning to come forward, including well-known personalities. Former U.S. President George Bush has it, as do former baseball slugger Kirby Puckett, former broadcaster Joel Aldred, and the late feminist Kay McPherson. I have it, too.

Peripheral vision fades
It’s not caused by too much reading or poor lighting. It’s not a tumour or cancer. And it’s not contagious. It’s dubbed “the thief in the night” because there are no advance symptoms, no warning signs. You don’t noce any loss of sight initially because it’s your peripheral vision that fades first – and slowly. Not until you realize you can see only the narrow area in front of you, as though you were looking at the world through a pipe, do you seek help – long after a lot of irreparable damage has been done.

In some cases, glaucoma strikes suddenly and dramatically with swift, permanent damage. Dr. Blair Fearon, a specialist in general practice, says he encounters two or three such cases a month. One man whose eyes had been tested only a few weeks before, and pronounced fine, suddenly had blurred vision with halos around lights, violent nausea and a headache he compared to “being kicked by a donkey.”

His family rushed him down to the emergency ward. The diagnosis: advanced glaucoma. But by that time, it was possible to save only a small part of his sight.

Eye doesn’t drain

  • Think of the eye as nature’s camera. Images pass through its lens and are focussed on the light sensitive lining, the retina. These signals are then sent to the brain through millions of cells in the optic nerve at the back of the eye. Glaucoma is caused by a build up of fluid and pressure inside the eye, which damages the optic nerve.
  • Now think of the eye as a sink with a running faucet and an open drain. Normally, the fluid drains out quickly. But in people with glaucoma the drain becomes blocked – the buildup puts pressure on the optic nerve, causing cells to die and, gradually, peripheral vision is lost.

In most cases, if caught early enough, glaucoma can be controlled. But there’s no cure.
What’s frightening is that even those who visit an eye specialist regularly – as I did – and have routine pressure tests, glaucoma can be missed. Sometimes people who register very high pressure in an eye test don’t have glaucoma. But one in five people who register normal or low pressure, as in my case, do have it.

The only sure way to detect glaucoma is by having regular checkups with an ophthalmologist who will dilate your eye and then closely examine the retina and the optic nerve.

Controlling glaucoma
Provided it’s detected in time, in all but 12 per cent of people, glaucoma can be controlled with eye drops, which reduce the amount of fluid and pressure. Other drops help clear the meshwork in the eye’s drain.

If the drops can’t relieve the pressure, surgery or laser surgery is the next step. Tiny holes are made in the meshwork of the drain to allow the fluid to flow out and help reduce pressure. This can be done with a local anesthetic with a 70-90 per cent rate of success.

Once a person has been diagnosed with glaucoma, in addition to the drops, which must be taken at exact intervals, he or she must also visit an ophthalmologist regularly to check how much damage has been done to the optic nerve.

Even though drops are taken once or twice a day at controlled intervals, patients generally experience a steady deterioration of their sight. Gradually, glaucoma cuts off many activities most of us take for granted – such as driving a car or walking safely in traffic. And always hanging over you is the thread of going completely blind.

What causes glaucoma?
Why does the pressure build up in some eyes and not others? No one can be sure, but some factors are:

  • Low blood pressure which results in not enough blood supply to the eye
  • Myopia or near-sightedness
  • Diabetes
  • Some genetic factors. If any close relative has had glaucoma or lost his or her eyesight, you have a one in 10 chance of getting it.

Two areas Dr. Trope believes crucial:

1. Testing everyone after age 35 at least every three years, and after 60 every two years.
2. Identifying as early as possible anyone who has a family history of glaucoma.

Lack of research, funds
According to Dr. Trope, there has been very little advancement in the understanding of glaucoma in almost 30 years. Yet he feels there are two promising fields that need exploration:

1. Genetics, in order to identify those with a tendency to get glaucoma
2. Regeneration of the optic nerve.

In Canada, researchers have made some remarkable discoveries in the field – often with the help of the Glaucoma Research Society of Canada (a privately funded charitable organization dedicated to research). But money spent on research lags far behind the U.S. As more and more Canadians in our aging population face a possible loss of their sight, the pressure is on to raise funds to find a permanent cure.

Journalist Doris Anderson was editor of Chatelaine magazine from 1953 to 1977. Well-known as a feminist activist, she’s a former president of the National Action Committee on the Status of Women.