FEATURE

Sight saved

Early diagnosis and better treatments are helping glaucoma patients like Marc Roy preserve their vision

Sight saved
Marc Roy required immediate care for his condition.
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What is glaucoma?

New surgical technique saves time, money

BY HOLLI MONCRIEFF
Winnipeg Health Region
Wave, September / October 2014

Marc Roy first realized he had a problem with his vision in 2007.

"During the Christmas holidays, I noticed my left eye was somewhat cloudy," the Collège Louis-Riel principal says.

Initially, he was diagnosed with iritis, an often-painful inflammation of the iris. In his case, it became chronic, and, for the next seven years, he was treated by a number of eye specialists. He was prescribed anti-inflammatory eye drops, which he used every day. Unfortunately for Roy, these drops caused another problem.

"Three years ago, my eye started to feel lethargic and heavy. You don't normally feel your eyes, and I could feel them. It was like my eye was getting bigger, like it was pushing against my eyelids," he says.

Roy was referred to Dr. Gdih Gdih, a staff surgeon at Misericordia Health Centre's Eye Care Centre. In short order, Gdih determined that Roy had glaucoma, a condition that can lead to blindness.

As Gdih explains, glaucoma is caused by a buildup of fluid in the eye. A healthy eye produces a certain amount of fluid, which then naturally drains away. If the fluid does not drain away fast enough, it can put pressure on the optic nerve, leading to glaucoma.

As it turns out, increased pressure on the optic nerve is a major side-effect of anti-inflammatory eye drops like the kind Roy was taking.

"It's a very common cause of glaucoma that a lot of people aren't aware of," says Gdih.

Indeed, Roy's condition had progressed to the point that he required immediate surgery. Normally, the intraocular pressure of a normal eye would be 10 to 20 millimetres of mercury (mmHg). The pressure on Roy's eye was 40 mmHg.

"We needed to lower the pressure to save his sight," says Gdih. Roy was Gdih's last patient on a Friday afternoon. By Monday, he was undergoing surgery.

The swiftness of events took Roy by surprise. "I didn't even know what glaucoma was," he says. "It's not something people talk about when you're 35 years old."

That's largely because the risk of developing glaucoma - the leading cause of irreversible blindness in the world - starts to increase significantly after the age of 40, and the risk continues to increase with each additional decade," according to Dr. Lisa Gould, a glaucoma fellowship-trained ophthalmologist and staff surgeon at the Eye Care Centre.

Fortunately, the condition is not as devastating as it once was, says Gould, who is also an associate professor in the Department of Ophthalmology at the University of Manitoba. The rate of blindness from glaucoma has been dramatically reduced over the last few decades, even as the rate of the disease has remained stable.

A study published earlier this year in the journal Ophthalmology underscores the point. It says the likelihood of blindness in glaucoma patients 20 years after diagnosis has fallen by at least half in the last generation. The study, conducted by a group of researchers that included an ophthalmologist from the Mayo Clinic, was based on a review of medical records of people living in Olmstead County, Minnesota.

Gould says she believes the experience in Canada would be similar, if not better.

She attributes the overall drop to earlier detection and better treatment. "Our ways of detecting the disease have improved. If you catch people at an early stage, they're much less likely to go blind," she says.

And once detected, there are more treatment options available. "The only way we can treat glaucoma right now is by lowering the intraocular pressure," she says. "In the past, medications were quite limited and surgery had a higher risk. Now there are several different categories of drops available and many people can avoid surgery. There are more options for laser treatments available as well."

The early stages of open angle glaucoma, the most common type of glaucoma, have no symptoms. "This is why glaucoma is called a 'thief in the night.' It can be stealing your vision without you knowing it," says Gould. "The straight ahead and detailed vision is usually preserved in the earlier stages, so people aren't always aware they're losing their vision around the centre. By the time someone starts to have symptoms, the disease is already moderately advanced."

That's why it is important to see an ophthalmologist or optometrist for glaucoma screening on a regular basis. Since glaucoma is usually related to the aging of the eye, those who are older should be tested more often.

Anyone with high risk factors should be tested every year or two after age 35. According to Gould, risk factors for open angle glaucoma include raised eye pressure, a family history of the disease, myopia (short-sightedness), circulatory diseases (such as abnormal blood pressure, heart disease and diabetes), prolonged prednisone use, and a previous eye injury. Sleep apnea, hypothyroidism and vasopastic disorders (such as migraine headaches, and Raynaud's phenomenon) have also been identified as risk factors in some studies, though further research is required to clarify their significance.

Certain ethnic groups, including people of African descent, are also thought to be at a higher risk. Some lifestyle factors may play a role. Recent studies have shown a link between heavy coffee consumption and glaucoma. One also has to be careful about over-the-counter supplements. For example, glucosamine has been associated with increased intraocular pressure.

Glaucoma screening takes about 60 minutes. In addition to a full eye examination, the optometrist or ophthalmologist will need to take a full medical history, as certain medications and diseases can increase the risk of glaucoma or even mask the disease.

People who have had LASIK surgery should notify their optometrist or ophthalmologist before being screened for glaucoma. LASIK surgery will result in a thinner cornea, which can cause false pressure readings.

Gould says the eye examination for glaucoma involves several steps. The vision is checked (both detailed vision and the field of vision). The eye pressure must also be measured. The most accurate method is with "applanation tonometry," a technique that requires touching the surface of the eye after a drop of anesthetic is applied. "It should not be painful," says Gould. The drainage system of the eye is then viewed with a special lens, and then, through a dilated pupil, the optic nerve is viewed stereoscopically to determine if there are any glaucomatous changes, she says.

 In open angle glaucoma, the first line of treatment is with medicated eye drops.

"The eye drops we use today are much more convenient and have fewer side-effects," says Gould. Occasionally, people will have systemic side-effects, such as shortness of breath, fatigue or achy joints from one of the medications. Local side-effects are common and often minor, such as stinging, low-grade redness or mild irritation. Prostaglandin drops cause the eyelashes to grow longer and darker, and may cause the iris to change colour. Localized allergic reactions and sensitivities can occur. They are not serious but when they occur, the drop has to be discontinued.

If eye drops don't sufficiently lower the intraocular pressure, then laser treatment of the drainage system (laser trabeculoplasty) can be performed.

During this procedure, a laser is focused upon the eye's drain, changing the drainage system in very subtle ways so that fluid is able to pass more easily out of the drain. The procedure is painless, and can be performed in either a doctor's office or an outpatient facility.

If medication and laser fail to control the eye pressure, or are not expected to control the eye pressure, then a surgical procedure, usually a trabeculectomy, is performed. Temporarily, pills to reduce fluid production in the eye can be prescribed, but pills are not used for long-term treatment, except in difficult cases of glaucoma in which the patient is not a good candidate for surgery, or previous surgery has failed.

During a trabeculectomy, the surgeon creates a passage in the sclera for draining excess eye fluid. A flap is created that allows fluid to escape, but which does not deflate the eyeball. When a trabeculectomy fails, or is not expected to work, other drainage devices (such as an Ahmed valve) can be implanted.

Some patients no longer require glaucoma medication after surgery. Of those who still need medication, most will have improved control of their intraocular pressure.

Glaucoma surgery is performed as an outpatient procedure. The number of post-operative visits to the doctor varies, and some activities, such as driving, reading, bending and heavy lifting must be limited for two to four weeks after surgery.

As it turned out, treatment by drops, laser and pills was not an option for Roy.

As Gdih explains, Roy had significant damage to his optic nerve. Since his glaucoma had progressed to the point where his intraocular pressure had to be lowered immediately, a drainage device known as an Ahmed valve was inserted into his affected eye.

An Ahmed valve is a small silicone tube that extends into the anterior chamber of the eye. The tube is connected to one or more plates, which are sutured to the surface of the eye, and are usually not visible. Fluid is collected on the plate and then absorbed by the tissues in the eye.

"Shunts and valves are meant for advanced glaucoma where you want the eye pressure to be very low. Eye stents involve a minimally invasive glaucoma surgery," Gdih says. "The outcome of surgery has improved because we're using medication to raise our success rates."

Roy recovered from his initial surgery very well. "He had a very good outcome. His vision was 20/20 uncorrected and his pressure was perfect," says Gdih.

Unfortunately, things did not turn out as well as they could have. Glaucoma surgery of any type requires two weeks of limited activity, followed by a gradual return to normal activity levels. Patients need to avoid lifting anything over ten pounds, and this limit is gradually increased by the eye surgeon.

When Roy was cleared to lift between 20 and 30 pounds, a neighbour asked him to help with sandbagging.

"I did move a few sandbags, and moving one is moving too many. I basically tore my eye apart," Roy says. "It's not easy to stitch up a tear, and stitches in the eye were painful, but Dr. Gdih is a godsend."

Thanks to the advances in glaucoma treatment, Roy was still able to retain some of the sight in his left eye.

"With all the trauma done to my eye and the damage done by the sandbagging, I've lost 70 per cent of my vision in the left eye, but my intraocular pressure is sitting perfectly where it's supposed to," he says. "Have faith in the specialists who are treating you. Listen to their advice and follow it diligently. You're not Superman, no matter how young you are."

These days, Roy takes special care with his eyes, wearing sunglasses whenever he's outdoors and avoiding any situation that could be potentially harmful.

"Take care of your senses. You don't know what you've got until you're going to lose one," he says. "If you feel uncomfortable about something, don't be scared to go in and get it checked out."

Holli Moncrieff is a Winnipeg writer.

Wave

About Wave

Wave is published six times a year by the Winnipeg Health Region in cooperation with the Winnipeg Free Press. It is available at newsstands, hospitals and clinics throughout Winnipeg, as well as McNally Robinson Books.

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