Last month, we discussed using rigid gas permeable (RGP) contact lenses to help patients who still need correction following refractive surgery. Soft lenses are also an option for many post-LASIK patients, especially when the residual refractive error is small.

Making soft lenses work

Post-LASIK patients are better candidates than RK patients for soft lenses; they display less abrupt mid-peripheral corneal changes, and neovascularization isn't an issue because the limbus is untouched. In addition, disposable lenses make it affordable to switch lenses if the patient's refractive power changes.

The downside of soft lenses for these patients is that they're not normally designed for an oblate-shaped cornea. Blinking can cause the lens to buckle or flex and become aberrated. Fortunately, several specialty lenses that address this problem are now available:

�         The Softperm lens. The center of this combination lens from Wesley Jessen is a gas permeable lens; the periphery is a soft contact lens "skirt." The 14.3-mm diameter lens is sterilized using chemical systems. It's available in base curves from 7.1 to 8.1 mm, and powers from +6 to -13 diopters.

�         The Flexlens Post-Refractive Lens. This soft lens, from X-Cel Contacts of Duluth, Ga., is specifically designed for these patients. It functions like a reverse geometry RGP lens, incorporating a central optic zone that's flatter than the mid-periphery. Base curve options range from 6.0 to 9.9 mm; diameters from 10 to 16 mm. All powers are available, but only in a spherical design.

�         The Flexlens Piggyback Lens. This lens features a piggyback design. The patient places a gas permeable lens into a groove in the soft contact lens.
Because of this unusual design, the patient must have good hand-eye coordination. For that reason, I use this lens as a last resort when other lenses fail to maintain centration.
The Piggyback Lens is available in all powers, with base curves ranging from 6.0 to 10.8 mm, and overall diameters from 12.5 to 16.5 mm. The diameter of the cutout ranges from 6.5 to 12.5 mm. The RGP lens is usually cut 1 mm smaller than the diameter of the cutout.

Managing complications

Complications are more likely to occur in post-surgery patients. Watch for:

�         Decentration. If this occurs, a change in parameters may be necessary.

�         Excessive deposits on the lenses. Make sure your patient cleans the lenses thoroughly -- especially if they're nondisposable specialty lenses.

�         Neovascularization from limbal impingement. This is most likely to be a problem with patients treated using the older RK techniques (i.e., incisions to or through the limbus). The soft lenses rub the limbus, producing neovascularization. This can lead to hemorrhaging and additional scarring. (RGP lenses may be more appropriate for these patients.)
Post-RK patients treated more recently, with shorter and fewer incisions (the mini-RK technique), may be able to use soft high DK/L lenses because of the 2- to 3-mm clear zone between the limbus and the end of the incision.

Timely follow-up

It's important that you follow these patients closely. I recommend seeing them on the following schedule:

�         first follow-up visit: 1 to 2 weeks after fitting

�         second visit: 1 month after fitting

�         third visit: 3 months after fitting

�         regular visits every 6 months.

This schedule should work equally well for RGP or soft lens wearers.

Dr. Koffler is director of the Kentucky Center for Vision in Lexington, Ky., and associate clinical professor of ophthalmology at the University of Kentucky Medical Center. He currently serves on the board of directors of the Contact Lens Association of Ophthalmologists, and is past president of the Kentucky Academy of Eye Physicians and Surgeons.