glaucoma: the 'silent medical disorder' that most of us don't know we have
glaucoma can only be detected through a routine eye exam, and if left untreated, it can lead to permanent damage, vision loss and blindness.
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these four common eye disorders are on the rise and they are stealing our sight
the federal government has yet to follow through on its 2003 promise to implement a national vision health plan.
may 18 2022
7 minute read
vision loss and blindness affect 1.2 million canadians, and it can be treated or prevented in 75 per cent of cases. getty
if eyes are the window to the soul, cataracts and other eye diseases are like frosted glass. or shutters, depending on the severity.
the four most common eye disorders — cataracts, glaucoma, macular degeneration and diabetic retinopathy — are on the rise, simply because we’re living longer, and all these conditions are age-related, says vancouver ophthalmologist dr. jean chuo.
what are cataracts?
“cataracts are like wrinkles,” says chuo. “if you live long enough, you’re going to have them. it’s just a matter of time and a matter of severity. i usually tell my patients, which they don’t find funny, that if you don’t have cataract surgery during your lifetime, you died too early.”
on the bright side, surgery for cataracts, which is a gradual clouding on the eye’s lens, has improved immensely. chuo says 30 years ago you’d be hospitalized because the surgical wound was so big. “we literally just squeezed it out,” she says. “and sometimes, unfortunately, the cataract came out and so did the rest of the inside of the eye,” leading to higher complication rates.
today the wound is 2.7 mm. the cataract itself, however, is one cm, so to fit it through the small opening, it’s broken up using an ultrasound probe and sucked out. it’s then replaced with an artificial lens which is so soft “we can roll it up like a newspaper and inject it into the eye through that 2.7 mm wound and, once in place, it will slowly open up by itself.”
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she says she can adapt that lens to the condition, such as near-sightedness, far-sightedness or astigmatism, although you may still need glasses for reading. the surgery itself is done in about 20 minutes on an outpatient basis.
to help delay the inevitable, get regular eye exams, don’t smoke, don’t drink alcohol to excess, follow a healthy diet and wear sunglasses.
what causes glaucoma?
glaucoma is actually a group of eye disorders that damage the optic nerve, caused by abnormally high pressure in the eye due to a build-up of fluid. however, chuo says there are many people with glaucoma whose eye pressure is normal.
“we don’t know why some people have low pressure glaucoma,” she says. “it’s likely a difference of pressure between the brain and the eyeball. or it’s a difference in anatomy that’s surrounding the optic nerve that makes these individuals more susceptible despite normal eye pressure.”
many forms of glaucoma, which affect over 400,000 canadians, have no warning signs and the effect is so gradual that you might not notice a change in your vision until it’s at an advanced state. untreated, it can lead to permanent and irreversible vision loss and blindness. it’s more prevalent among those with high blood pressure or diabetes, have a family history, are of african, asian or hispanic heritage, or had previous eye injuries.
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“there’s a pattern of damage to the optic nerve that [causes] tunnel vision, so you start to lose vision peripherally,” chuo says. “we call it the ‘silent thief’ because it’s such a gradual onset.”
she says treatment for glaucoma currently focuses on decreasing eye pressure through drops, laser or surgery. unfortunately, she adds, none will bring back vision but will hopefully prevent further damage.
larissa moniz, ph.d, director of research for fighting blindness canada , says there’s a new class of surgery called minimally invasive glaucoma surgeries that involve smaller incisions with fewer side effects.
“some are more effective than others and they aren’t all available in an even way across the country because more research needs to be done to show they are cost effective and effective,” says moniz. “this is still a very active area of research.”
she says researchers are looking at ways to protect the optic nerve from further damage as well as restorative strategies. stem cell therapy to replace optic nerve damage is also in the works.
age-related macular degeneration affects 2.5 million canadians
age-related macular degeneration (amd), caused by a combination of genetics and environment (smoking, diet), can result in loss of central vision, particularly for those over 50. in advanced stages, you can lose the ability to drive, see faces and read fine print. it affects about 2.5 million canadians.
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although he has no family history, never smoked, drank excessively or is overweight — in fact he’s very fit from 60 years of playing hockey and lifting weights — doug purdy of vancouver was diagnosed with both glaucoma and dry macular degeneration. he gets monthly injections for his amd, and eye drops for his glaucoma.
“it’s a bit weird, the notion of a needle stuck in your eye,” he says. “they do topical freezing, there’s a little penetration and you can kind of feel it. but i’m an old hockey player, i’ve taken pucks in the face and i have a high pain tolerance so it doesn’t really bother me. i just put myself into a zen state and there you go.”
there are actually two types of amd — dry and wet. dry is the most common, and happens when the macula becomes thinner and less able to support the retina’s photoreceptors, the cells that convert light into visual signals. it usually occurs one eye at a time, which is why, in early stages, you may have no signs or symptoms. in later stages, your vision may be blurry or straight lines may appear wavy.
“the majority of people start off with dry amd, and one in 10 will progress to wet amd,” says moniz. “even though most people with dry amd don’t have vision loss, some do progress to advanced dry amd, which is also called geographic atrophy, a small subset of dry amd [which can lead to permanent vision loss].”
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wet amd, while less common, can lead to severe vision loss. it occurs when abnormal blood vessels start to swell in the back of the eye, leaking fluid and blood, hence “wet” amd, and can create a large blind spot in the centre of your vision.
there is no treatment for early stage dry amd, but regular eye exams can catch progression. for intermediate and late-stage amd, treatment with specially formulated supplements called areds or areds2 can decrease progression to wet amd by about 25 per cent.
treatment for wet amd involves injections, usually monthly or bi-monthly, of anti-vascular endothelial growth factor (anti-vegf) drugs that can stop the bleeding and reduce the damage from leaky blood vessels. “in one third and up to half of patients, vision actually improves, because it dries up the blood,” says chuo.
moniz says current research is looking at making the treatments last longer, so injections could be four or six months apart, as well as gene therapy trials in which your own cells make the drug for you. also, stem cell therapy for vision loss due to dry amd is in clinical trials, as are treatments to reduce the inflammation, which are showing promise.
diabetic retinopathy can cause blurred vision
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there are several types of retinopathy, but all involve disease of the small retinal blood vessels, according to the journal of the american medical association. the most common is diabetic retinopathy which, as the name suggests, is related to diabetes.
according to fighting blindness canada, it affects about one million canadians and, in early stages, may not have symptoms. if diagnosed early, it can be managed and vision loss prevented. if untreated, it may develop into diabetic macular edema, where damaged blood vessels leak into the macula, causing blurred vision and distorted images.
it can be classified as either proliferative (growing) or non-proliferative (not growing). in non-proliferative, the blood vessels in the retina weaken, and can lead to retinal hemorrhages. symptoms can be mild or non-existent, and treatment may not be necessary. keeping blood sugar levels under control, as well as following diet and exercise recommendations from health professionals, can help control the progression.
in proliferative, the advanced stage, new blood vessels grow to compensate for the damaged ones, but they are weaker and more susceptible to breaking, which can lead to bleeding into the vitreous cavity and blurred vision.
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treatments to prevent further vision loss include injectable drugs (steroids or anti-vegf), laser surgery, or vitrectomy surgery.
vision loss and blindness affect 1.2 million canadians, and it can be treated or prevented in 75 per cent of cases. moniz says fighting blindness canada continues to lobby the federal government to implement a national vision health plan, which it promised back in 2003, but has yet to follow through on, as well as broader access to treatment, including for covered eye exams at younger ages.
in the meantime, doug purdy says, “do all things in moderation because there are factors like being overweight, diet, smoking, etc. that can damage your eyesight. but most important is to get regular eye checkups, because [eye specialists] are not simply looking at the eye chart, they’re looking for other eye conditions.”
for more information about keeping your eyes healthy and to connect with others, visit fighting blindness canada, glaucoma research society of canada and the canadian association of optometrists .
robin roberts is a vancouver-based writer.
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