Here's the rub on keratoconus

Issue: May 1996

BOSTON—For some time, research has pointed to a connection between keratoconus and aggressive eye rubbing. To help patients—particularly those with allergies—avoid the risk of developing keratoconus, optometrists should educate them about the dangers of eye rubbing and help them stop.

Donald Korb, OD, a private practitioner here who sees many keratoconus patients, is emphatic about informing patients of the risks of rubbing, telling them, "This is one of the most important things you'll ever be told because keratoconus is one of the few things that can change your life."

The exact cause and effect has not been determined, Korb said, but "what is established is a very profound relationship between keratoconus and a certain type of eye rubbing: a firm, circular motion with the knuckle or heel of the hand."

Aggressive rubbing

Most people rub their eyes a little, said John Herman, OD, who sees many keratoconic patients in his private Pittsfield, Mass., practice. But with aggressive rubbers, he said, the total time they rub their eyes might be more than an hour a day. "Those who rub their eyes stand the chance of bringing on keratoconus or increasing its severity," Herman said.

Using fluorescein, the effects of eye rubbing can be seen "almost immediately," he said. Some epithelium is rubbed off and a criss-cross pattern on the front of the eye is created that resembles the pattern on the tip of cones. "It looks like there's something similar in each instance," Herman said.

Korb said rubbing results in chemotactic activity, which, in turn, may cause collagen breakdown in the eye. When an eye with keratoconus is biopsied, frequently chemical changes and the presence of enzymes associated with rubbing are found. "It may well be that these enzymes are not part of the disease itself but may be a result of eye rubbing," Korb said.

Genetics or environment?

Herman said nearly all his keratoconic patients rub their eyes aggressively, as do most of the allergy patients he sees. However, the amount of blame that should fall on genetics or environmental factors is still unclear.

"Certainly plenty of people who have ocular allergies don't have keratoconus," Herman said. "Part of the story has to be heredity and part of the story has to be eye rubbing. The theory is that those who are prone to it may bring it on sooner or more severely by rubbing the eye."

Make sure lenses fit correctly

Optometrists can play a big role in preventing their allergy sufferers from the rubbing that may lead to keratoconus.

For contact lens wearers, "The most common defensive mechanism is to have patients take their lenses out and constantly clean them during allergy season," Korb said.

Herman said to make sure the lenses fit right, so there's no external, mechanical reason for the patient to rub the eye. "And, certainly, a dirty lens will induce rubbing and itching," Herman said.

ODs can also help patients eliminate the allergy. Herman said optometrists can recommend that their allergy sufferers see an allergist and get an allergy panel examination to find out the source and get treatment. "There's no medication that will get rid of allergies," Herman said. "They're only eliminated by repeated exposure to the allergen and by letting the body build up its own indifference."

But ODs still need to stay involved, he said, because the process of helping the body build up resistance can take years, and during that time patients could still be rubbing their eyes.

A three-step line of defense

Korb outlined a three-step "defense line" to help remove the allergy cause. The first step is to "clean up your environment," he said: Cleaning or removing pillows, animals, dust, mold, plants, etc.

The second is to flush the eyes with sterile saline solution that is preservative-free. "It's of minimal benefit to put in one or two drops," Korb added. "You have to use copious amounts."

The third step is to keep the outside of the lids and the eyelashes clean, "because they're part of the environment, too," Korb said.

Herman said scaling lids, meibomitis and blepharitis may keep the tears from working, diminishing the capability of the eye to clean itself.

To prevent rubbing, the optometrist can ask that everyone the person lives with inform the patient when they see him or her rubbing, said Korb.

Whenever the eye feels itchy, patients can put a cold compress or ice on the eye, because cold constricts the vessels and alleviates the itching.

Corneal topography valuable

Herman said corneal topography can be invaluable for diagnosing early cases of keratoconus.

He recently bought a topographer, which he said has helped him in discovering four new cases of keratoconus "that would have been very hard to diagnose in a normal slit lamp evaluation."

To help prevent full-blown onset of the disease in early cases, Herman said early keratoconus patients "should be corrected by the method that is easiest on the cornea, and that means eyeglasses. If that becomes no longer visually possible, then we use a soft lens on them. When nothing else works, then put a rigid lens on them."

There are different kinds of cones, and "they are amenable to different kinds of treatment," Herman added. "And there are also different expectations of visual acuity from person to person. Some people are extremely happy seeing 20/30 and other people hate it. You have to determine what kind of person you're dealing with."

Commercial drops can help

Herman said several commercial drops—particularly mast cell inhibitors —can help alleviate ocular itching caused by allergies. In bad cases, nonsteroidal anti-inflammatories can be used, but he said to avoid steroids.

Whatever the drug, Korb said, "Anything that goes on the eyes of these people should not have a preservative, because—even in wetting solutions—they can cause further troubles."