In fact, not seeing is exactly what the crisis is all about.

Today 80 per cent of clients of the Canadian National Institute for the Blind (CNIB) are over 60, an age demographic that statistics say will double over the coming quarter century.

"If nothing else changes, we can expect the number of people to be affected by vision loss to more than double in the next 25 years, so we need to come up with some miraculous treatments or prepare for an onslaught of people with vision loss," says Dr. Keith Gordon, director of research for the CNIB.

By far the most serious culprits in robbing Canadians of their vision are glaucoma and age-related macular degeneration (AMD), Gordon says. Cataracts are also common but well treated with surgery. Glaucoma can often be controlled with medication but, while there are some new medications showing promise with AMD, it remains the biggest challenge, he says.

Prevention is a key factor in averting this crisis and an Uxbridge, Ont. optometrist, Dr. Vitu Banh, believes one of the simplest preventive strategies is wearing sunglasses.

Ultra-violet, or UV, rays, are stronger today because of the thinning ozone layer and are often cited as a contributing factor to skin cancers. And they are a huge problem for the eyes as well, Banh says.

"Macular degeneration is linked to UV damage," he says. "It's a form of radiation and any radiation can change the structure of the cell, which causes problems."

He also cites incidence of cataracts at younger ages as an impact of UV. "We used to see cataracts at ages like 60 or 70. But now we are seeing people in their 40s with cataracts, and these are people who have been outdoors a lot, skiing, sunbathing, construction people."

Gordon agrees that sunglasses are a sensible form of prevention and are recommended by the CNIB.

"There is believed to be a correlation between the time people spend in the sun and the development of AMD," he says. "At this stage it's not known if it's causative or not but there is a correlation between the two. So what we are recommending is that people wear sunglasses when they go out and that the kids start wearing sunglasses at a younger age to prevent the potential of a lifelong build up of these radicals that could cause damage to the macula. Whether or not wearing sunglasses is going to have a long-term effect, I think, still has to be established but it makes sense to do so."

Banh points out that it's also important to wear sunglasses year round, not just in the summer when the sun seems brightest and hottest.

The damage doesn't necessarily come from direct sunlight but from reflecting off surfaces such as snow. And research has shown that 80 per cent of the UV rays can penetrate even a very dark cloud.

It's also important that the glasses have the proper protective coating, he maintains. This doesn't mean they must be dark, which many people don't like, or even expensive. "Often we test a pair of $20 sunglasses and find they do as well as a $200 pair," Banh says.

Online information from the University of Waterloo School of Optometry indicates that dark lens tint does not necessarily mean that the lens blocks UV rays. If you are outside a lot, choose sunglasses that have tags or labels that say "UV protection." Look for lenses that provide protection from both UVA and UVB radiation and "sunglasses that have tags or labels saying that they meet the requirements of the ANSI Z80.3 or CSA Z94.5 sunglass standards."

Regular eye examinations are important, says Gordon. "In the case of glaucoma there are no symptoms at all until one loses the peripheral vision," he says. "Peripheral-vision loss creeps in from the side and suddenly you realize you've lost quite a bit of your vision. In the case of AMD the changes are small so you don't notice day to day but if you were to compare how much vision you've lost to two or three months ago you'd see a big difference."

Yet Canadians are generally apathetic about this precaution. Gordon cites a study, a couple of years ago, by the Canadian Ophthalmology Society, that showed that 50 per cent of people hadn't had an eye exam in the previous five years, or ever.