Blind World


Cornea-shaping contact lenses damage some eyes.





October 16, 2004.

By CAROLYN ABRAHAM,
The Globe and Mail.




TORONTO:- Susanne Corbin had worn glasses since she was 10 years old, so in the beginning it was as liberating as walking barefoot.


She could swim at the cottage, spectacle-free. She could ski. She could buy funky non-prescription sunglasses. All this, she thought, and she never had to undergo the daunting prospect of a laser cutting into her cornea to correct her shortsightedness. All she had to do was pop inrigid contact lenses before bed.


Custom fit to squeeze and flatten the curvature of her cornea, the lenses helped to correct her sight while she slept. Come morning, she peeled them off, enjoyed the day with better vision and then reinserted the lenses at bedtime, when, like a Cinderella effect, her cornea rebounded to its usual shape. Ms. Corbin raved about it to her friends.


"I was amazed," the 43-year-old Toronto woman said. "I kept saying to people, 'and I didn't have to have laser eye surgery.' "


But her dream treatment soon became something of a nightmare. And her story is now one of four troubling Canadian cases linked to the use of corneal reshaping lenses.


A Globe and Mail investigation, which has triggered a probe by Health Canada, has raised questions about how these lenses, now surging in popularity, especially among children, are being regulated, marketed, sold and monitored.


In August, 2001, six months into her nightly routine, Ms. Corbin's right eye began to sting. Three weeks later, her head "in constant excruciating pain" and her eye swollen shut, Ms. Corbin learned she had contracted an acanthamoeba infection.


It was burrowing through her cornea, a one-celled parasite so tenacious that anti-parasitic agents, antibiotics, even chlorine, can be powerless to flush it out.


Ms. Corbin lost her sight in one eye for two years. A software company accounts manager, she missed 10 months of work. In June, she underwent a corneal transplant, but it remains unclear how well she will see. "You think, 'Hey, it's a contact lens,' " said Ms. Corbin. "You think, 'Hey, how unsafe can that be?' "


At least 20 reports of vision-impairing infections have been linked to the use of corneal reshaping lenses in Asia and Australia in the past two years, and now the first troubling cases are coming to light in Canada.


The procedure, known as orthokeratology, involves wearing hard lenses overnight that squash the cornea into a shape that can correct nearsightedness. This allows a patient to be free of glasses or contact lenses the following day. When the patient stops wearing the lenses nightly, the cornea generally returns to its original shape within a few days.


But many ophthalmologists warn that these lenses increase the risk of serious, even sight-threatening infection because they are worn overnight, fit more tightly than soft contact lenses and block oxygen from reaching the eye. These factors are believed to stress the cornea and leave it susceptible to bacteria and parasites.


Canadian ophthalmologists have recently uncovered four cases of serious infection linked to the lenses. Along with Ms. Corbin's experience, there is a 12-year-old girl in Vancouver lucky to recover from a corneal ulcer, a 14-year-old Calgary girl who has suffered permanent vision loss in her right eye, and a 15-year-old girl in Edmonton left legally blind after contracting an acanthamoeba infection in both eyes. That young patient is now awaiting a double corneal transplant -- for the second time.


"A lot of people are promoting this without telling anyone that serious complications can occur," said Toronto ophthalmologist Allan Slomovic, the clinical director of cornea service at the University Health Network who treated Ms. Corbin. "There haven't been any large studies, so we simply don't know the overall infection rate."


Dr. Slomovic, researcher Natasha Yepes and colleagues from Western Canada have submitted their patient cases to the journal Cornea.


A licensed manufacturer is legally required to report adverse events associated with its product to Health Canada, but no doctor is obliged to inform the manufacturers, or the government, resulting in a critical gap in the system.


Unlike drugs, overnight reshaping lenses are considered to be medical devices in Canada; as such they do not have to undergo clinical trials before they can be licensed for sale, but rather a "pre-market review." This involves the manufacturer signing a declaration that it has evidence on file showing its product is safe and effective, but not necessarily having to provide it before it receives a licence.


The Globe has found this burgeoning field offers little comfort to the consumer. Studies evaluating the risks and benefits of overnight reshaping lenses are limited and there are no guarantees that the orthokeratology lenses sold in Canada have been tested for that purpose.


Only one company, Paragon Vision Sciences of Arizona, has been licensed in Canada to sell them. But there are at least five other brands of orthokeratology lenses on the market. Fred Lapner, head of Health Canada's medical devices branch, confirmed these have never been issued a licence for orthokeratology.


Optometrists governed by provincial bodies are the practitioners who most often prescribe these lenses, and just as a drug approved for pain relief can be prescribed as a blood thinner, optometrists are free to prescribe "off label" uses of certain lens designs.


But, according to Health Canada, it is the manufacturer or importer who must license the lenses if they are to be sold to doctors for overnight corneal reshaping.


Without a licence, there is no public assurance lenses have proven to be safe or effective, nor what, if any, adverse reports a manufacturer has received about them. Health Canada, for example, knew nothing of the four Canadians who suffered the lens-related infections until it received phone calls from the Globe this week.


Kim Dix, manager of Health Canada's medical devices compliance unit, is now looking into the licensing matter. "In a case where a device does not have a licence, there are certain steps that are taken to stop sales of the device, there may be recalls involved as well, it depends on the factors involved in the situation," Mr. Dix said.


While the promise and pitfalls of laser eye surgery have captured most of the attention in the vision-correction market in the past decade, the $3-billion (U.S.) contact-lens industry has been quietly fighting back with orthokeratology.


One Alberta lens manufacturer pegged the growth of the practice at 10 to 15 per cent a year in the past five years, with roughly 300 optometrists offering it across Canada. Children, too young to undergo laser eye surgery while their corneas are still developing, have become a prime target market.


Yet most of the reshaping lenses available on the market have either been tested in very limited numbers of children, or none at all. Dr. Slomovic, who is also president of the Canadian Cornea External Diseases and Refractive Society, said: "The particular danger here is that a lot of people going in for ortho-k are young kids, and the warnings should be made particularly clear to them."


Promoters bill orthokeratology, which has been around for 30 years, as a safe, non-surgical alternative to allow vision-impaired patients to see, unaided, during the day. They believe that new lens materials and designs significantly reduce the risk of infection, and that the overnight procedure allows the naked eye to recover from any stresses and soak up maximum oxygen by day.


But Oliver Schein, an ophthalmology professor at Johns Hopkins University in Baltimore, was the author of a key 1994 finding that wearing lenses overnight increases infection risk eightfold, still feels the new generation of orthokeratology lenses leave the eye more vulnerable to disease than regular daily-wear lenses.


"To me, it's self-evident, the simple closure of the eyelid during sleep reduces the amount of oxygen that gets to the cornea," he said. At the same time, the cornea begins to shed some of its cells. "So if you add another barrier with a contact lens to the eye, it's more likely you will have trauma to the surface layer of the cornea," Dr. Schein said.


This interferes with the production of tears, he said, stressing the cornea further, "giving the chance for bacteria to set up shop, and start to get a little inflammation going.


"The unanswered question is what is the magnitude of that risk," Dr. Schein said. "We don't know whether this happens in one in 100 patients, or one in 1,000.


"My own personal belief is that this was a product that gained approval for use in adolescence, but most of the research was done in adults, and they were relatively small studies. My concern is that this is not well tested in younger groups."


Joe Sicari, president and CEO of Paragon, which has roughly 30 eye-care practitioners selling its reshaping lenses, is forthright about the appeal the therapy holds in the child and adolescent markets. Even the parents of those as young as 7 are attracted, he said: "Mom and Dad are always wondering whether Johnny is wearing his glasses at school, whether he can see the board to learn."


But Vivian Hill, a pediatric ophthalmologist in Calgary, firmly believes no child can properly give informed consent for a temporary treatment that may have permanent side effects.


Last year, she treated a 14-year-old who had been using ortho-k lenses for two years and ended up in hospital in pain. Although the girl believed she had removed the lenses, Dr. Hill discovered the one in her right eye was still in place, and beneath it, a bacterial infection had festered into a large ulcer in the centre of her cornea.


The girl has been left with a corneal scar. "This is permanent loss of vision that no glasses will help. This is what you're risking," Dr. Hill said. "She almost lost her eye."


Yet Dr. Hill, like other ophthalmologists, has heard from the parents of the patients they have treated that orthokeratology has been offered to them not simply as temporary means of correcting vision, but as a mode of slowing the progression of myopia.


"The parents are being told by people selling [the lenses] that the child's myopia is getting worse, and if they don't put these lenses in, the myopia is going to continue to get worse," Dr. Hill said. "I'm not saying it's all optometrists, but they are being pressured by some."


Although there is no hard evidence that ortho-k can slow the progression of myopia, it has become one of the most attractive -- and contentious -- reasons parents opt for this procedure for their children.


Joan Hansen, president of the Canadian Optometrists Association, does not practice ortho-k, but feels parents worry that without the overnight lenses their child might end up wearing the high-prescription "coke-bottle glasses."


"We always work on the premise that if you put hard contact lenses on a child that they would not end up as shortsighted as if you had done nothing," Dr. Hansen said.


This hope has made orthokeratology a popular therapy among Asians, who suffer the world's highest and most severe rates of myopia.


Herman Shen, an optometrist in Burnaby, B.C., who largely serves the Asian community, said he has prescribed the lenses to 400 patients, some as young as 8, in the past five years. "I actually had patients coming in, some of the recent Asian immigrants, asking me about it," Dr. Shen said. "A lot of Asian moms think the prescriptions [for glasses] will get too [strong]."


Dr. Shen said his young patients regard orthokeratology as a form of myopia control, something of a stop-gap measure to carry them through adolescence until they are old enough to undergo the potentially permanent fix of laser eye surgery.


"I may try it on my kid," said Dr. Shen, who noted that he has seen little more than a few cases of conjunctivitis and abrasions in children wearing the lenses.


The U.S. Food and Drug Administration prohibits ortho-k manufacturers from marketing their lenses as tools to slow myopia. Health Canada's Dr. Lapner said federal authorities would intervene if companies here made such an unsubstantiated claim.


But for a 15-year-old honours student in Edmonton who can no longer dream of being a fighter pilot, or an athlete or a microsurgeon, that information comes too late.


The girl, whose family declined to be interviewed, began wearing orthokeratology lenses when she was 11. She was only mildly shortsighted, but her parents followed the recommendation of the optometrist who told them the overnight lenses could keep her eyesight from getting worse, said Joseph Leong-Sit, a University of Alberta ophthalmologist.


Dr. Leong-Sit met her two years later, after "she had been relegated to sitting in the dark. Neither natural light nor room light could be tolerated. She was functionally blind in both eyes."


As with Ms. Corbin, the girl had contracted acanthamoeba parasitic infection, but in both eyes. She underwent a double corneal transplant 18 months ago that has restored some degree of vision: She can read her school exams, if they are written in large type.


But she has recently suffered rejection of the donated corneas, Dr. Leong-Sit said, and is awaiting a second double transplant. He has referred her to the Canadian National Institute for the Blind for assistance.


"The parents feel devastated that they gave consent for their child to start this treatment," Dr. Leong-Sit said. "And here they thought they were protecting her from advancing myopia."


The story of Dr. Leong-Sit's patient has made its way through the local optical community, with many members suggesting the infection was the result of improper care of the lenses. The girl has admitted to rinsing the lenses with tap water, which the acanthamoeba parasite commonly inhabits.


Those who practice ortho-k insist a good deal of the risk involving infections in children may have more to do with whether the patients are mature enough to take proper care of their lenses. But to paint the entire ortho-k practice as dangerous is wrong, said Rikke Dootjes, founder and president of Viscon Contact Lens Manufacturing Ltd. in Edmonton. "[Ophthalmologists] say they don't like [ortho-k] because there is no good science behind it. But there was not much science behind laser eye surgery."


Mr. Dootjes's company manufactures two brands of orthokeratology lenses for practitioners in five provinces. These include the Dream Lens, designed and patented by a Florida optometrist, and a generic known as AOK. He notes that there are at least two other brands available in Canada, the BE Lens and another generic known as Cardinal.


According to Health Canada's Dr. Lapner, none of the lenses Mr. Dootjes mentioned have received a licence to be sold as orthokeratology lenses.


Mr. Dootjes is unapologetic. He argues that these lenses have been sold for five years and use materials that Health Canada has licensed for use in extended-wear contact lenses. Of the Health Canada investigation into the matter, he said: "This will end up being for me a long, drawn-out argument."


Viscon pays the patent holder from $7 to $10 for each lens manufactured, and then sells them to the practitioners. They, in turn, fit them for patients and conduct follow-up visits, charging from $800 to $4,000, putting it on par with laser surgery, Mr. Dootjes said.


Optometrists have to make a sizable investment to do the fittings properly, investing in a $20,000 to $30,000 computer topography machine that allows them to measure dimensions of the cornea down to the micron. But not all of them make that investment.


One of Mr. Dootjes's concerns is that optometrists "can graduate from university with no experience fitting rigid lenses." Viscon has helped hold seminars on orthokeratology for the growing number of practitioners interested in the therapy.


Paragon requires that doctors take a two-hour certification course before fitting its lenses, a training program required by the U.S. FDA and Health Canada. But for those prescribing unlicensed lenses it is unclear what, if any, training is provided.


One on-line article in the Review of Optometry offered tips for how optometrists might get training. It is entitled Six Steps to Becoming an Ortho-K Expert.



Source URL: http://www.theglobeandmail.com/servlet/ArticleNews/TPStory/LAC/20041016/LENSES16/TPHealth/.




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