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Ears, Nose, Throat and Health

Contacts, taking care

Are You Using Contact Lenses Safely?

By Dr. W. Gifford Jones

July 8, 2000

Today 35 million North Americans wear contact lenses. They don't fall off, break or steam up. They're great for sports. Most people find them comfortable and more flattering than glasses. And they're also a great boon for patients following cataract surgery. But there is a downside and it's vital that users know about it.

Dr. Dwight Cavanagh, Professor of Ophthalmology, University of Texas Southwestern Medical School, at Dallas, warns that contact lens wearers may be at risk of corneal erosion. In fact, in some patients infections can be devastating. Dr Cavanagh stresses that this complication can occur with either soft, hard, extended or disposable lenses.

It's the old story that one rarely gets something for nothing. Good sense dictates that placing a foreign substance in the eye for many hours is bound to incur potential problems. Particularly when you realize that the human eye blinks 20,000 times a day.

This natural reaction moves a contact lens up and down over the eye. The distance over 24 hours is equivalent to three football fields in length! Small wonder that corneal injury may occur.

Dr.Cavanagh reported a three year study of patients wearing different contact lenses. Some wore soft or rigid lenses. Others rigid gas permeable (RGP) lenses. Or the new ultra�oxygen transmissible lenses.

Tests were then done to ascertain how well oxygen was transmitted through these various lenses. And was there any relationship between the number of bacteria stuck to the corneal cells and how much oxygen passed through the lenses?

Patients were then examined at regular intervals. Eye washes obtained corneal cells for study. These were examined for the presence of bacteria.

Dr. Cavanagh concluded that corneal ulcers were the result of three factors. Mechanical friction from prolonged use of contact lenses. How well bacteria adhere to the surface of the lens and how easily oxygen passes through the lens.

The ultra�oxygen transmissible lens, the best transmitter of oxygen, had the least amount of bacterial growth. (The brand name of the lenses was not revealed).

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There are several ways patients can decrease the risk of corneal ulcers. First of all, don't wear contact lenses when you sleep. And wear them less than 12 hours at a time. Remember that the only way oxygen gets to the eye is through the cornea which is covered by the contact lens.

Corneal ulcers can sometimes be traced to contaminated cleaning solutions and faulty care of the lens. So be sure to keep the lens clean.

Dr. Jerry Nolfi, a Toronto optometrist, says several products are available for lens care. He prefers "Complete Comfort Plus" because it performs several functions. It fights dryness, cleans the cornea and disinfects the surface of the eye.

Complete Comfort Plus contains hydroxypropyl methylcellulose which is present in products called artificial tears. This provides lubrication, retains fluid and makes the lens more wettable. A moist lens provides better comfort and allows people to wear the lens longer each day. It also contains sodium and potassium. These electrolytes wash away protein that forms on the cornea from natural tears.

Dr. Nolfi explains that disposable soft lenses consist of plastic and water. Consequently, if tear volume decreases slightly this causes an imbalance and the need for additional lubrication.

Contact lens users, Dr. Nolfi stresses, face another problem. The recycled air in office buildings is often dry. Moreover, constantly looking at a computer screen decreases the number of times the eye blinks. Complete Comfort Plus relieves this dryness and causes less discomfort for the person who must sit before the screen. This is an important point as patients are more likely to use it routinely.

I warned readers 13 years ago about the possible complications of contact lenses. Dr Mathea Allansmith of The Harvard Medical School reported at that time that contact lenses invariably caused a change in the ocular surface of the eye.

This sometimes triggers an allergic reaction causing blurred vision, mucous discharge and redness of eyes. By the end of the day patients feel as if their lenses are drying up in their eyes and they start squinting like Popeye.

The message is don't get careless with contact lenses. Your eye doctor can direct you to what he or she considers the safest lens. And remember, if you develop a "red eye", be sure to consult your doctor immediately.


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