Understanding and Avoiding Contact Lens Complications: Overwear Syndrome
Contact lenses are a wonderful mode of vision correction and provide an excellent alternative to eyeglasses, but patients should remember that they are medical devices, available by prescription. Like many other medical interventions, they are subject to complications and risk of adverse events.
Most contact lens-related complications involve either decreased oxygen levels getting to the cornea or lens care and cleaning issues. By following instructions as to wear schedules, lens replacement and cleaning regimens, contact lens wearers can virtually eliminate most sources of complications and adverse events.
Those complications caused by a decrease in oxygen flow to the cornea can also result in a loss of corneal sensitivity, so that a foreign body under the lens may not even be felt by the patient at all. Those complications that are caused by lens care and cleaning issues can result in a much higher risk of infections; some infections can be very serious, even vision-threatening.
For successful contact lens care and wear, your eyecare practitioner and you form a partnership; in it, the obligation of the eyecare practitioner is to provide quality contact lenses, the proper fit and give the patient information and resources to properly care for the lenses. It is the obligation of the patient to use the lenses according to instructions and care for them properly, using the correct solutions, to follow all instructions and ask questions if needed for clarification.
Signs and Symptoms of Overwear
Overwear syndrome is caused by just what one would expect it to be: overwearing contact lenses. This can take the form of wearing the lenses too long in a day, or even in sleeping with lenses on the eye that were not meant to be used in an extended-wear manner.
The actual culprit in overwear is a decrease in the amount of oxygen getting to the cornea from the atmosphere, and to a lesser extent, from the exchange of tears under the lenses.
Added factors like computer vision and its related dry eyes can add to the impact of overwear, because we don’t blink as often or produce as many tears overall when using a computer.
Improvements in lens materials have greatly increased the amount of oxygen getting through the lens, but even so, some patients have corneas that respond to decreased oxygen sooner than others.
In overwear, the patient will experience inflammation of the cornea (keratitis), redness and swelling of the conjunctiva (the transparent skin covering the whites of the eyes and lines the insides of the eyelids), varying degrees of lens intolerance, eyelid swelling, light sensitivity and corneal edema (swelling). Because a swollen cornea is also cloudy and not perfectly transparent, vision will be affected as well.
Overwear symptoms can be thought of as resulting from our eyes letting us know that they are also “tired,” of supporting a contact lens and that we should reduce our wearing time.
Overwear syndrome is usually bilateral because both eyes are subjected to the same lens type, but if the patient wears different lens types in each eye (as in the case of different amounts of refractive error, for instance).
Treatment of Overwear
The first thing to do is to eliminate the source of the problem by suspending all contact lens wear until all signs and symptoms are resolved.
With lens wear suspended, the cornea usually heals over the course of several days to weeks. Patients will often require switching to new lens materials that are extremely high in oxygen permeability. There are lens materials available today that cause almost no interference with the flow of oxygen at all, and these may prevent overwear from recurring again. Often daily disposable lenses are recommended.
Patients who have a case of overwear should not be in any extended-wear modality, but should remove their lenses every time they sleep, even just for a quick nap. Once a person has experienced the discomfort of overwear syndrome, he or she is usually very willing to do whatever it takes to prevent it from happening again.
Discontinuing contact lens wear totally is almost never required with today’s lens technology.
Overwear syndrome is much less frequent today than in the past, largely due to the huge technology leaps made in lens materials and designs. Patients experiencing symptoms over overwear syndrome should discontinue their contact lens wear and see their eyecare practitioner right away.