The Silent Thief of Sight

By: Jamie Bussin

Estimates are that over 728,000 Canadians are currently impacted by glaucoma – one of the leading causes of irrevocable blindness. And according to a recent survey,  45% of Canadians living with glaucoma had no prior knowledge of their disease before diagnosis. On Episode #227 of The Tonic Talk Show/Podcast I spoke to Dr. David Yan, the Opthamologist in Chief at Mount Sinai hospital and Glaucoma Service Director at Kensington Eye Institute, about the disease and its treatment.

Glaucoma is caused by high eye pressure damaging the optic nerve that transmits the light signals to the brain. It’s known as the ‘Silent Thief of Sight’ according to Dr. Yan, because unlike the other most common causes of blindness (diabetes, cataracts and macular degeneration) it is asymptomatic until very late in the course of the disease. It impacts your peripheral vision first and then your central vision. If you don’t notice that something is wrong, you don’t access the recommended treatment in time. Dr. Yan explains; “It is a disease that causes you to lose your vision very slowly, over the course of months or even years. Because we don’t know how much peripheral vision we should have, we ignore it. It’s dangerous, because if the peripheral vision loss occurs where our sight in each eye overlaps, it would be easy not to notice.”

The problem has been compounded in the last two years during Covid-19, as many Canadians have put off their regular eye exams. Dr. Yan confirms; “We’re finding that many more people are losing their vision during Covid-19 as compared to before. I think that the after effects of this will continue for years to come. The damage that was done due to glaucoma will persist through these patients’ lives and bring them much closer to risk of losing their vision.”

Dr. Yan was not surprised to learn that 45% of Canadians living with glaucoma had no prior knowledge of their disease before diagnosis. Because it attacks peripheral vision first, is incremental in nature and can’t be easily diagnosed by patients themselves, people don’t know they have glaucoma until their vision is significantly impacted. “This is why we advocate that Canadians have regular eye exams, so that we can diagnose the disease early enough that we can institute the treatments that will prevent blindness.”

Being able to access information regarding glaucoma is the strongest defence against people going blind from the disease; that they are aware of it, that they know what to do to check for it and be able to get treatment early. Fortunately, early treatment is effective. The usual way to start treatment is eye drops, which are fairly non-intrusive: Usually taken once or twice a day. As well there is laser treatment for more advanced cases. Laser treatment can be done as a first line treatment or in conjunction with the eye drops. Dr. Yan estimates that less than 5-10% of glaucoma patients require surgery these days -the caveat being that patients are diagnosed early. “The later you are diagnosed with glaucoma, the more likely you’ll require surgery during the course of your lifetime. But as long as you have useful vision in your eyes, it’s never too late to treat glaucoma.”