Warning Signs for CL Wearers
Q. I see many patients with keratoconus in my practice. At what point should I refer them to a surgeon?
A. The decision depends mainly on the severity of the patients condition. Some studies suggest that you can manage most keratoconus patients without surgery for up to 10 years.1
Spectacle correction is often enough to control myopia and astigmatism in the early course of the disease. Eventually, gas permeable contact lenses will likely be necessary to provide optimal vision. Patients generally begin with mild symptoms where things look distorted even with correction. They may notice their Rx changes more frequently, but spectacles or contact lenses can still provide adequate acuity, says Leawood, Kan., optometrist Jennifer Uhl.
As the condition progresses, patients may describe their vision with correction as if they were looking through ice or dirty glass. At this point, patients may simply need GP lenses, if theyre not already wearing them. Unless there is a question about diagnosis, or the optometrist does not have the necessary equipment, there is no reason to refer, says Dr. Uhl.
Fortunately, there are several contact lenses on the market specially designed for keratoconus patients. Try a variety of specialty fitting sets to see which will fit your patient best. Manufacturers will often work with you to find the best lens.
Fitting specialty lenses isnt more difficult than other contacts, its just time consuming. We set aside one afternoon a week to do new keratoconus fits. When you find the lens that works, its a very rewarding experience, says Dr. Uhl. A study conducted at Johns Hopkins University found a majority of keratoconus patients who were referred for keratoplasty could be successfully fitted with contact lenses and most remained in the lenses for five years or longer.2
Vogts striae, seen here, are one sign of keratoconus.
A referral is appropriate when you no longer have anything to offer the patient, Dr. Uhl says. Patients nearing the end stage of keratoconus may no longer be able to tolerate a contact lens. Or, you may be unable to get a lens to stay on the eye. Thats when surgical intervention is prudent, she says.
If corneal thinning progresses and the patient is at risk for scarring or perforation, immediate surgical
intervention is necessary. This is rare, however. These patients are not likely to perforate even when the apical thinning appears to be extremely thin, says Joseph P. Shovlin, O.D., of Scranton, Pa.
Keratoconus patients also need to be counseled about strict compliance to care regimens. The National Keratoconus Center Foundation urges patients to call their eyecare provider if they experience any of these symptoms:
Pain upon lens insertion, during wear or upon removal.
Burning, redness, tearing or discharge.
Inability to keep eyes open.
Severe photophobia, glare or haze.
White spots on the cornea.
Even so, Dr. Shovlin says, you should be concerned when there is progressive peripheral thinning. Although exceedingly rare, these patients should receive a surgical consult in order to minimize potential graft size to decrease the antigen load, he says.
Also, pay attention to patients who develop corneal hydrops. Vascularization in these patients may warrant a surgical consult.
The Center for Keratoconus (www.kccenter.org), a group that supports keratoconus research and education, says corneal transplantation is only necessary in about 10% of patients and has a success rate of 90%, though spectacle or contact lens correction may still be necessary. Visual rehabilitation generally takes about nine to 10 months, but visual correction can be prescribed as early as three months post-op.
1. Weed KH, McHee CN. Referral patterns, treatment management and visual outcome in keratoconus. Eye 1998;12(pt4):663-8.
2. Smiddy WE, Hamburg TR, Kracher GP, Stark WJ. Keratoconus contact lenses or keratoplasty? Ophthalmol. 1988;95:487-92.
