Laser visionaries
Since its introduction a decade ago, more than 100,000 Canadians have undergone laser eye surgery to correct vision problems. However, the procedures have risks that need to be weighed before the surgery takes place.
Full Text (1267 words)
Copyright Rogers Publishing Limited Feb 15, 1999
Doug Bezpalko began wearing eyeglasses as a rambunctious eight-year-old growing up on a cattle ranch near Elk Point in northeastern Alberta. He lost them in the mud, they were trampled on by calves, and they were always expensive to replace. Finally, in 1997, Bezpalko, an engineering technologist in Calgary, was ready to have his eyes operated on. He was 38 and still active--enjoying water skiing and racquetball--but loathed seeing his glasses fog up with maddening regularity and having to take diligent care of contact lenses. Like many other Canadians, he turned to laser eye surgery. For $4,800, an ophthalmologist nicked the cornea of Bezpalko's eye with a diamond-edged scalpel and then reshaped it with a laser beam, giving him excellent vision. "I'm elated," says Bezpalko, who has not had to wear glasses now for close to a year and a half. "I can't say enough."
There are no precise figures available on how many Canadians have had laser eye surgery to correct nearsightedness (myopia), farsightedness (hyperopia), and astigmatism (caused by an irregularly shaped cornea). But Dr. Patricia Teal of Fort Erie, Ont., past president of the Canadian Ophthalmological Society, estimates that more than 100,000 patients have undergone the procedure since its introduction to Canada a decade ago. And as success stories like Bezpalko's are told, laser eye surgery's popularity seems to be growing, despite the fact that neither medicare nor most private medical plans pay for the expensive procedure. But along with the potential for remarkable results, the procedure entails risks that have to be weighed carefully.
Results vary from case to case. Sometimes, the procedure merely means the patient uses a weaker corrective lens instead of getting rid of it entirely. And in rare instances there have been serious complications, including damage to a patient's vision that cannot be corrected even with glasses. "People should be wary of being swept along by hype," or by the lower prices some eye clinics are offering across Canada, says Teal. "It's not like picking up a dress on sale. You're actually having someone permanently change the shape of your eyes."
There are two main types of laser eye surgery: the older, more established PRK technique; and the LASIK procedure, which has come to the forefront in the past two or three years. Both alter the shape of the cornea, the eye's clear front surface. Both use an excimer laser, a so-called cold laser of ultraviolet light that removes successive layers of the cornea. Each layer is the thickness of about one micron--1/1,000th of a millimetre (or 1/100th the diameter of a fine human hair). Typical procedures remove 50 to 70 microns from the 500-micron thickness of a cornea. The excimer laser does not burn, but instead breaks the molecular bonds of cells in the cornea, in effect vaporizing them, sending up a plume of water and cellular debris that the patient does not see, says Bezpalko's ophthalmologist, Dr. Robert Mitchell, head of the Mitchell Eye Centre in Calgary.
The patient does not feel the laser during either procedure because the eyeball is anesthetized with drops (there are no needles involved). A metal or plastic device then holds the eyeball in place. With PRK, the laser strikes the surface of the cornea, carving away a prescribed amount of tissue. Recovery is somewhat painful, and the patient's vision does not clear for at least a week. Full recovery requires three to six months.
With LASIK, a technique commonly referred to as "flap and zap," the surgeon nicks the cornea with a computer-operated scalpel, then folds part of it back like a hinge. The laser then trims tissue from the interior of the cornea. Once the LASIK treatment is completed--in about 30 minutes for both eyes--the flaps are closed and remain in place without stitches. Vision clears in as little as a day and there is virtually no pain during recovery.
As with all surgeries, there are possible negative consequences. "It's possible," Teal says, "that you could be left permanently with an inability to see 20/20--no matter what anybody does." Other potential side-effects include reduced night vision, seeing haloes around lights at night and infections that can cause scarring. Health Canada warns that anyone whose work depends on night vision should be cautious about having laser eye surgery, and that there is no information about possible lifetime risks associated with the relatively new procedures.
Ironically, laser eye surgery in some cases creates a need for glasses in situations where the patient did not previously require them. Specifically, nearsighted patients over the age of about 45 will almost certainly need reading glasses once their distance vision is corrected. That is because, generally speaking, nearsighted people can read without glasses but need them for seeing further away. After the surgery, the horizon comes into focus unaided. The ability to read without glasses, however, is lost because the corneas have been reshaped in such a way that "it's as if you have your glasses on all the time," Teal says. "What you're doing is trading your uncorrected near vision for uncorrected distance vision." Younger patients do not need the reading glasses because their eye muscles are more supple and therefore adaptable.
There is a way around the problem. Mitchell in Calgary offers all of his patients over 45 what he calls "mono-vision," in which one eye is corrected for distance, while the second is carved just enough to allow a person to read, though not so much as to create a perceptible imbalance or alter depth perception. "As a result, the brain uses one eye for distance, the other eye for near," Mitchell says, "and the patient is usually unaware of which eye they're using."
Another unwelcome possibility is regression--a spontaneous return of the eye to less than perfect vision (though usually better than the eyesight that the person started out with). Early PRK procedures, for example, often required a second or even a third operation. But newer lasers have improved PRK's effectiveness. Because of the dearth of national statistics on laser eye surgery, it is hard to say how many patients suffer unwanted side-effects. But Health Canada estimates that they can occur in as many as five per cent of all operations. If the corrective work is minimal, Teal says, the risks diminish to less than one per cent of cases.
Meanwhile, improvements in software and hardware are happening rapidly and new lasers are constantly becoming available. In Canada, the medical devices bureau of the Health Protection Branch regulates the sale of lasers and requires testing and clinical trials before each model goes on the market. "The technology is just incredible," says Dr. Fred Lapner, an adviser with the medical devices bureau. Still, Lapner says a laser remains no more than a surgical tool. "The outcome," he adds, "depends on the skill of the ophthalmologist."
Bruce Waugh, a Toronto lawyer who has had the PRK procedure three times, is looking forward to trying LASIK this month. Three years ago, he paid $4,500 to correct nearsightedness and a significant astigmatism. Six months later, his eyesight regressed to the point where he needed to wear glasses again, although his vision was significantly better than it had been. Two more operations--at no charge--yielded similar results. "People going into this should realize that some people will need it twice," says the 49-year-old Waugh, "and a smaller percentage will need it more than that." As Teal notes, laser eye surgery has improved the vision of thousands of Canadians. But, she cautions, "It's something you want to go into with--so to speak--your eyes wide open." *** END OF DOCUMENT ***
Full Text (1267 words)
Copyright Rogers Publishing Limited Feb 15, 1999
Doug Bezpalko began wearing eyeglasses as a rambunctious eight-year-old growing up on a cattle ranch near Elk Point in northeastern Alberta. He lost them in the mud, they were trampled on by calves, and they were always expensive to replace. Finally, in 1997, Bezpalko, an engineering technologist in Calgary, was ready to have his eyes operated on. He was 38 and still active--enjoying water skiing and racquetball--but loathed seeing his glasses fog up with maddening regularity and having to take diligent care of contact lenses. Like many other Canadians, he turned to laser eye surgery. For $4,800, an ophthalmologist nicked the cornea of Bezpalko's eye with a diamond-edged scalpel and then reshaped it with a laser beam, giving him excellent vision. "I'm elated," says Bezpalko, who has not had to wear glasses now for close to a year and a half. "I can't say enough."
There are no precise figures available on how many Canadians have had laser eye surgery to correct nearsightedness (myopia), farsightedness (hyperopia), and astigmatism (caused by an irregularly shaped cornea). But Dr. Patricia Teal of Fort Erie, Ont., past president of the Canadian Ophthalmological Society, estimates that more than 100,000 patients have undergone the procedure since its introduction to Canada a decade ago. And as success stories like Bezpalko's are told, laser eye surgery's popularity seems to be growing, despite the fact that neither medicare nor most private medical plans pay for the expensive procedure. But along with the potential for remarkable results, the procedure entails risks that have to be weighed carefully.
Results vary from case to case. Sometimes, the procedure merely means the patient uses a weaker corrective lens instead of getting rid of it entirely. And in rare instances there have been serious complications, including damage to a patient's vision that cannot be corrected even with glasses. "People should be wary of being swept along by hype," or by the lower prices some eye clinics are offering across Canada, says Teal. "It's not like picking up a dress on sale. You're actually having someone permanently change the shape of your eyes."
There are two main types of laser eye surgery: the older, more established PRK technique; and the LASIK procedure, which has come to the forefront in the past two or three years. Both alter the shape of the cornea, the eye's clear front surface. Both use an excimer laser, a so-called cold laser of ultraviolet light that removes successive layers of the cornea. Each layer is the thickness of about one micron--1/1,000th of a millimetre (or 1/100th the diameter of a fine human hair). Typical procedures remove 50 to 70 microns from the 500-micron thickness of a cornea. The excimer laser does not burn, but instead breaks the molecular bonds of cells in the cornea, in effect vaporizing them, sending up a plume of water and cellular debris that the patient does not see, says Bezpalko's ophthalmologist, Dr. Robert Mitchell, head of the Mitchell Eye Centre in Calgary.
The patient does not feel the laser during either procedure because the eyeball is anesthetized with drops (there are no needles involved). A metal or plastic device then holds the eyeball in place. With PRK, the laser strikes the surface of the cornea, carving away a prescribed amount of tissue. Recovery is somewhat painful, and the patient's vision does not clear for at least a week. Full recovery requires three to six months.
With LASIK, a technique commonly referred to as "flap and zap," the surgeon nicks the cornea with a computer-operated scalpel, then folds part of it back like a hinge. The laser then trims tissue from the interior of the cornea. Once the LASIK treatment is completed--in about 30 minutes for both eyes--the flaps are closed and remain in place without stitches. Vision clears in as little as a day and there is virtually no pain during recovery.
As with all surgeries, there are possible negative consequences. "It's possible," Teal says, "that you could be left permanently with an inability to see 20/20--no matter what anybody does." Other potential side-effects include reduced night vision, seeing haloes around lights at night and infections that can cause scarring. Health Canada warns that anyone whose work depends on night vision should be cautious about having laser eye surgery, and that there is no information about possible lifetime risks associated with the relatively new procedures.
Ironically, laser eye surgery in some cases creates a need for glasses in situations where the patient did not previously require them. Specifically, nearsighted patients over the age of about 45 will almost certainly need reading glasses once their distance vision is corrected. That is because, generally speaking, nearsighted people can read without glasses but need them for seeing further away. After the surgery, the horizon comes into focus unaided. The ability to read without glasses, however, is lost because the corneas have been reshaped in such a way that "it's as if you have your glasses on all the time," Teal says. "What you're doing is trading your uncorrected near vision for uncorrected distance vision." Younger patients do not need the reading glasses because their eye muscles are more supple and therefore adaptable.
There is a way around the problem. Mitchell in Calgary offers all of his patients over 45 what he calls "mono-vision," in which one eye is corrected for distance, while the second is carved just enough to allow a person to read, though not so much as to create a perceptible imbalance or alter depth perception. "As a result, the brain uses one eye for distance, the other eye for near," Mitchell says, "and the patient is usually unaware of which eye they're using."
Another unwelcome possibility is regression--a spontaneous return of the eye to less than perfect vision (though usually better than the eyesight that the person started out with). Early PRK procedures, for example, often required a second or even a third operation. But newer lasers have improved PRK's effectiveness. Because of the dearth of national statistics on laser eye surgery, it is hard to say how many patients suffer unwanted side-effects. But Health Canada estimates that they can occur in as many as five per cent of all operations. If the corrective work is minimal, Teal says, the risks diminish to less than one per cent of cases.
Meanwhile, improvements in software and hardware are happening rapidly and new lasers are constantly becoming available. In Canada, the medical devices bureau of the Health Protection Branch regulates the sale of lasers and requires testing and clinical trials before each model goes on the market. "The technology is just incredible," says Dr. Fred Lapner, an adviser with the medical devices bureau. Still, Lapner says a laser remains no more than a surgical tool. "The outcome," he adds, "depends on the skill of the ophthalmologist."
Bruce Waugh, a Toronto lawyer who has had the PRK procedure three times, is looking forward to trying LASIK this month. Three years ago, he paid $4,500 to correct nearsightedness and a significant astigmatism. Six months later, his eyesight regressed to the point where he needed to wear glasses again, although his vision was significantly better than it had been. Two more operations--at no charge--yielded similar results. "People going into this should realize that some people will need it twice," says the 49-year-old Waugh, "and a smaller percentage will need it more than that." As Teal notes, laser eye surgery has improved the vision of thousands of Canadians. But, she cautions, "It's something you want to go into with--so to speak--your eyes wide open." *** END OF DOCUMENT ***
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