CCR -- A Hazard of
Extended Wear

BY BARRY FARKAS, O.D. & VINCE MCGLONE, O.D.
JULY 1996

Michelle, a 52-year-old extended wearer of disposable, hydrogel lenses, appeared for a routine examination in 1992. She had been wearing her lenses for up to two weeks at a time since 1987 and had been asymptomatic at all previous evaluations.

Previous biomicroscopic examinations had revealed no significant corneal epithelial compromise or appearance. Although we had observed a mild neovascularization 360 degrees in scope with less than one millimeter of corneal penetration, there were no signs of edema, even upon early morning evaluation.

On this particular visit, Michelle presented with a biomicroscopically observable sign we had not seen in previous evaluations -- bilateral corneal compression rings (CCR).

CORNEAL COMPRESSION RINGS ARE JUST ONE OF THE AVENUES THAT CAN LEAD TO PERIPHERAL ULCERS.

CCR: A WARNING SIGN

CCR seems to occur as a result of an inward pressure on the cornea by the peripheral portion of a contact lens as it dehydrates and puckers. Limbal hypertrophy, a condition that is often associated with CCR, has been reported by Rodger Kame, O.D. The shared concern relates to the entrapment of debris and waste products while the patient wears the lens in this puckered state.

A classic antigen/antibody reaction subsequent to such an occurrence may well be one culprit in the all-too-frequent occurrence of peripheral (sterile) ulcers.

We advised Michelle to restrict extended wear to a maximum of two to three nights to allow for adequate venting of entrapped material. Regretfully, she ignored our advice and presented with a peripheral ulcer OS exactly two weeks later.

Subsequent extended wear was limited and uneventful, but at each evaluation, Michelle asked to resume one- to two-week extended wear since "everything has been so perfect for so long."

Happily, the most recent evaluation, almost three years since we first observed the CCR, found Michelle wearing her lenses primarily on a daily wear basis with only minimal CCR occurrence. Since the compression rings appear to be secondary to some individual tear composition alteration, extending this patient's wear schedule seems an unnecessary risk.

EVALUATING SIGNS & SYMPTOMS OF CCR

In recent years, we have noticed CCR occurrence in a number of asymptomatic extended wearers who have not yet developed any peripheral ulceration. It's rare, however, that patients presenting with peripheral ulcers, do not also display CCR.

We can further categorize a CCR by its depth and completeness. A shallow or incomplete CCR would seem to pose less risk of toxic entrapment by at least partially venting these substances. Indeed, we have noticed that individuals who display this incomplete CCR formation are at considerably less risk than those whose CCR is more complete and deep.

Clearly, there are likely a number of conditions that may create an environment for the occurrence of peripheral ulcers. CCR with its debris entrapment potential and added mechanical pressure on the limbal vasculature is just one of those possibilities.

The appearance of a CCR is an important sign in hydrogel extended wear evaluations. Along with signs of oxygen deprivation, it is among the most significant and easily recognizable hazards to look for in extended
lens wearers. CLS

Dr. Farkas is in private practice limited to contact lenses. He is past chair of the AAO Cornea and Contact Lens Section and is a trustee at the Pennsylvania College of Optometry.

Dr. McGlone is in private practice in the Washington, D.C., area and spent four years working in the offices of Dr. Farkas and Kassalow. He is a graduate of the University of California, Berkeley, College of Optometry.