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Ears, Nose, Throat and Health

Risks, eye surgery

Surgery For Near-sightedness

By Dr. W. Gifford Jones

July 31, 1999

How would you like to have good vision without glasses or contact lenses? Benjamin Franklin who invented the first bifocals in the 18th century would say "yes" to that question. Today ads promise that an operation called radical keratotomy can make this dream come true. But before you agree to this surgery it's important to know both the risks and the benefits.

  The shape of the eyeball and cornea, the transparent structure covering the iris and pupil determines whether or not you are nearsighted or farsighted.

  People who are nearsighted have an eyeball and cornea that's too arched. This means images will be focused in front of the retina (the back part of the eye). Those who are farsighted have an eyeball and retina that's too flat. Here the image is focused behind the retina.

  A machine known as an excimer laser produces pulses of light that can alter the shape of the cornea. By so doing light rays from objects will focus on the retina with greater precision.

The operation known as radical keratotomy can be done in two ways. The original laser treatment PRK (photorefractive keratectotomy) does not require cutting of the cornea. Rather, laser energy is just applied to the surface of the cornea.

  A newer version is called LASIK (laser in-situ keratomileusis). In this procedure a thin flap of tissue is raised in front of the cornea. The laser is then applied to the tissue beneath the flap.

  Patients who are treated with LASIK usually see well the day after the surgery. PRK patients require one to two weeks before vision recovers. And it may take up to six months to achieve maximum improvement.

  Excessive haze resulting from an abnormal healing is one of the primary complications after PRK. It is virtually non-existent after LASIK.

  Neither PRK or LASIK surgery involves significant pain. But LASIK patients experience less post-operative discomfort. This is because the sensitive outer cornea is not involved. In addition, the flap acts like a band-aid to facilitate healing and decreasing post-operative discomfort. PRK patients sometimes feel as though a piece of sand is stuck in the eye for several days.

The disadvantage of LASIK is that it involves surgical creation of a flap. Most of the complications are mild. But improper development of the flap could lead to further surgery. But for people with severe nearsightedness the LASIK technique is preferable.

  Surveys show that most patients are pleased with the results regardless of the method. Some patients achieve 20/20 vision. But some advertising claims that people can toss away their glasses are too optimistic.

  Dr. Penny Asbell, a spokesperson for the American Academy of Ophthalmology says, "Very few patients will have perfect vision and patients must have realistic expectations."

  Surgery, for instance, may eliminate the need for glasses or contacts during the day. But patients often require glasses for night driving or in conditions of low light.

  In one study 435 people who agreed to radical keratotomy were examined five years later. 36 percent of the 323 who had surgery on both eyes still needed glasses.

  A report from Johns Hopkins University claims that about 5 percent of patients continue to need glasses all the time following PRK. Another 15 percent continue to require glasses occasionally especially at night or when lighting is poor.

  There's also a possibility of other problems such as infection, scarring or a one percent chance of worse vision, even with glasses, than before the surgery.

  Peeling a few layers of tissue off the cornea also weakens it making it more susceptible to injury. And it may make it more tedious to perform cataract surgery later in life.

  Some patients following PRK ended up with the opposite problem. The surgeon removed too much corneal tissue and they became farsighted.

  The most predictable post-operative difficulty is that the eye continues to age. And you will in all probability need reading glasses in later life regardless of whether or not you have the operation. Nor can this operation prevent other aging problems such as cataracts and macular degeneration where central vision becomes dim.

Patients suffering from chronic medical conditions such as diabetes, glaucoma, severe hypertension, rheumatoid arthritis or heal poorly are not good candidates for this operation. If you're vision seems to be changing too quickly the surgery should be delayed. And no one knows what the long-term results will be. My advice is to give it considerable thought before making a decision.


W. Gifford-Jones M.D is the pen name of Dr. Ken Walker graduate of Harvard. Dr. Walker's website is: Docgiff.com

My book, �90 + How I Got There� can be obtained by sending $19.95 to:

Giff Holdings, 525 Balliol St, Unit # 6,Toronto, Ontario, M4S 1E1

Pre-2008 articles by Gifford Jones

Canada Free Press, CFP Editor Judi McLeod