Are your contact lenses as safe as you think?

ARE YOUR CONTACT LENSES AS SAFE AS YOU THINK?

Are contact lenses as safe as we alwaysthought they were? That's a question many contact lens wearers may be asking after seeing frequent stories in the news media about vision-threatening problems with contact lenses.

The contact lens problem that hasreceived the most press recently is a possible link between extended-wear lenses and corneal ulcers--eruptions on the surface of the eye (cornea). There are many types of ulcers; some are caused by a variety of infections. Symptons include vision changes, redness of the eye, eye discomfort or pain, and excessive tearing. In severe cases, these lesions can lead to partial or complete blindness. Corneal ulcers can occur in people who wear hard, rigid gas-permeable, or soft lenses, but they can also occur in people who don't wear contact lenses at all.

However, preliminary data compiledby FDA suggest that users of extended-wear contact lenses have a greater chance of developing corneal ulcers than people who wear other types of contact lenses. This could be due to a buildup of deposits on the lenses, or the lenses preventing enough oxygen from reaching the cornea (the cornea has no blood vessels; it gets oxygen directly from the air). The number of cases of corneal ulcers associated with all lenses seems to be increasing, with 135 reported to FDA during 1986 compared to 35 in 1985. A study sponsored by a group of contact lens manufacturers is under way to determine more definitively if there is an increased risk of corneal ulcers with extended-wear lenses. The study, which should be completed within a year, will complement FDA's efforts to uncover the cause of the reported problems.

Although definitive data on extended-wearlenses and corneal ulcers are not yet available, changes are already evident in the way extended-wear lenses are being used. First, fewer are being prescribed. Also, doctors are prescribing shorter wearing times--one to two weeks rather than 30 days. And doctors are monitoring patients more closely, with frequent follow-up visits to screen for problems.

While research continues on cornealulcers, another sight-threatening eye problem has recently been associated with the use of contact lenses. Approximately 40 cases of acanthamoeba keratitis, an infection of the cornea caused by an amoeba, were reported last year to the U.S. Centers for Disease Control. The cases were primarily among users of daily-wear lenses. This has prompted experts to reconsider problems that may be common to both extended-wear and daily-wear lenses.

Acanthamoeba, which also causesa rare form of meningitis, was only recently linked to eye infections. Symptoms are similar to those of corneal ulcers. The number of cases of acanthamoeba keratitis is small among the roughly 20 million contact lens wearers in the United States, but those who get it can really suffer. Like corneal ulcers, acanthamoeba keratitis can scar the cornea, leading to partial or complete blindness. Compounding the difficulty in treating acanthamoeba keratitis is the difficulty in diagnosing the infection. It mimics the symptoms of herpes virus eye infections and, in fact, certain herpes treatments can cause it to subside, only to flare up again when treatment is ended. It can then only be treated surgically. Certain drugs are being tested, but their effectiveness is not established.

CDC studies indicate that acanthamoebakeratitis is strongly linked to the use of homemade saline solution. Most victims were using non-sterile saline solution made from salt tablets and distilled water to rinse their lenses after disinfection. Homemade saline solution should never be used as wetting solution or as a rinsing solution after disinfection. Directions for use in the labeling for salt tablets clearly indicate that rinsing contact lenses after disinfection with this non-sterile saline solution can cause problems.

The types of problems associatedwith contact lenses, and their causes, are many and varied. The causes most often cited by eye experts are certain patient characteristics--for example, dry eye (not enough tears); the lens material or its design; inadequate direction from the eye-care practitioner; and improper lens care.

A recent survey of 200 extended-wearcontact lens users turned up some two-thirds who were not following lens-care instructions. Only 10 percent retained the printed instructions they received. Yet, many of these wearers believed they were following instructions correctly.

Regardless of whether poor care directlyresults in corneal ulcers or acanthamoeba keratitis, lack of proper lens care can damage lenses and shorten lens life. Eye doctors are stressing that patients should not treat contact lenses as innocuous cosmetic items, but as the medical devices they are.

The array of solutions needed to carefor contact lenses, especially soft contact lenses, can be intimidating. And procedures vary with the type of lens. More care is needed for soft contact lenses than hard lenses. Nevertheless, here are some "Do's and Don'ts" that are true for all lenses: