Computer Speeds Contact Fittings

Fitting contact lenses can be a trial-and-error experience, as many of the nation’s 22 million wearers know.

After all, it’s not a simple process: An eye doctor has dozens of lens designs and types from which to choose; wearers have a variety of vision abnormalities.

But new computer software programs promise to make lens fitting easier, decreasing time and money spent at the eye doctor’s office.

The programs, recently introduced by several companies, help create a topographical map of the cornea. The doctor uses the map and computer to “fit” different lenses without actually touching the patient’s eye. The process continues until the best fit is found.

The software is run on existing computer systems, which some eye doctors already use to detect corneal disease, plan surgery and, to a much lesser extent, fit lenses.

“The patient looks into a cone-like device with illuminated rings,” says Stephen Klyce, a Louisiana State University professor, describing TMS 1, a system he helped develop.

Most eye doctors use a method called keratometry to evaluate corneal curvature and abnormalities, then prescribe the best corrective lens, says Penny Asbell, an associate professor of ophthalmology at Mt. Sinai School of Medicine, New York. The new software systems measure 80% or more of the corneal surface, she says, much more than the surface measured by keratometry.

Corneal mapping probably won’t be in widespread use for contact-lens fitting for five or even 10 years, experts say. One stumbling block is the price. At $25,000 and up, the system’s price tag is out of reach for many eye doctors, industry experts say. Until corneal mapping becomes common, there are other ways to improve the fit of contact lenses:

A special harmless dye used in small amounts can ease the fitting of rigid gas-permeable lenses, says Rodger Kame, a Los Angeles optometrist who also uses the corneal mapping system to fit contact lenses. After the dye is introduced, a doctor can evaluate the topography of the cornea under ultraviolet light, Kame says.

A special set of “diagnostic” lenses, placed on a patient’s eye, can help doctors evaluate fit before deciding on a specific lens.

Giving your doctor adequate information about your lifestyle can boost the chance of a successful fit, says optician Carl Moore, president of Concise Contact Lens Co. and a past president of the Contact Lens Manufacturers Assn. According to Moore, every eye doctor should ask such questions as: “What do you do for a living? Do you sit under an air-conditioning unit at work? What do you do for fun?” Listening carefully can help a doctor choose the best type of lens.