Corneal lesions may signal underlying systemic conditions

Corneal artifacts may mimic more serious lesions, making them difficult to diagnose and treat.

Issue: September 10, 2009

Superficial corneal lesions may point to serious systemic disease, but not all lesions require treatment, an expert said here.

Ivan R. Schwab, MD, discussed common corneal lesions and strategies for treating them at Cornea Day preceding the American Society of Cataract and Refractive Surgery meeting in San Francisco.

Common lesions include Thygeson’s superficial punctate keratitis, epidemic keratoconjunctivitis, basement membrane dystrophy, late mucous plaque keratitis of herpes zoster and interstitial keratitis, Dr. Schwab said.

Many lesions are difficult to diagnose and treat, and some corneal artifacts may masquerade as more serious lesions.

“Certainly, corneal scars, trauma and such can mimic any of these [conditions] at almost any time at almost any depth,” he said.

Treating with low-dose steroids

Thygeson’s superficial punctate keratitis commonly presents as discrete opacities separated from the limbus, Dr. Schwab said.

“And if you look more closely, you find that they are made up of individual dots,” he said.

The condition is best treated with low-dose steroids or 2% cyclosporine administered three or four times daily and gradually reduced to once daily or once weekly. Soft contact lenses may be effective, but they pose a risk of infection.

Epidemic keratoconjunctivitis presents with subepithelial opacities that typically appear in the central cornea.

“They’re different from side to side,” he said. “That is, one side will have far fewer lesions than the first side affected.”

Lubrication is the optimal treatment for epidemic keratoconjunctivitis. Corticosteroids are addictive and rarely needed but may be appropriate for some patients in low doses.

“Sometimes, I put patients on corticosteroids because they’re so miserable,” he said. “If you feel you have to put them on corticosteroids, use the lowest dose possible, but it will be addictive.”

Use caution with debridement

Opacities associated with basement membrane dystrophy may be discrete or grouped, with sharp edges, almost uniform density and small cysts. These lesions are readily apparent with a dilated pupil and do not usually require treatment, Dr. Schwab said.

Late mucous plaque keratitis, associated with herpes zoster, is signified by lesions that stand just above the corneal epithelium and may be visualized with rose bengal or lissamine green staining.

Basement membrane dystrophy and mucous plaque keratitis of herpes zoster seem suitable for debridement. However, debridement may lead to nonhealing epithelial lesions or neurotrophic ulcers.

“Beware of debridement if you’re wearing a soft contact lens because inevitably what happens is that you get infectious crystalline keratopathy,” Dr. Schwab said. “I know because I’ve done this more times than I wish to admit.”

If herpes zoster lesions require treatment, low-dose steroids, cycloplegia, oral antiviral medications and anti-inflammatory drugs are most effective. He recommended close observation and patient counseling for basement membrane dystrophy and mucous plaque keratitis.

Genetic dysfunction

Interstitial keratitis may point to syphilis, Epstein-Barr virus, leprosy, sarcoidosis and tuberculosis. Those diseases must be diagnosed and may require systemic treatment, Dr. Schwab said.

Salzmann’s nodules commonly appear in the periphery of the cornea and are typically seen in women with long-term contact lens wear. He said he normally does not treat Salzmann’s nodules unless they cause astigmatism or some other corneal irregularity, adding that they may result from genetic factors.

“It may also be a stem cell or fibroblast dysfunction, so there may be some underlying genetic dysfunction here,” Dr. Schwab said. – by Matt Hasson

Ivan R. Schwab, MD, can be reached at University of California-Davis, 4860 Y St., Suite 2400, Sacramento, CA 95817; 916-734-6070; fax: 916-734-6992; e-mail: irschwab@ucdavis.edu.