CORNEA & CONTACT LENS Q&A

A Glaring Problem after LASIK

Edited by Joseph P. Shovlin, O.D.

Question: I am comanaging more LASIK patients these days. How can I help my patients who complain of nighttime glare?  —Jack W.H. Wong, Hong Kong

Answer: First rule out misalignment of the cap and the formation of central islands, says Andrew S. Gurwood, O.D., of the Pennsylvania College of Optometry. If central islands are present, the patient may require additional procedures. Also check for corneal defects such as epithelial erosions or corneal abrasions. If either is present, treat as you would any other corneal abrasion.

Corneal topography can help you determine whether the glare is due to decentration of the treatment, irregular astigmatism or a disparity between the pupil size and treatment zone size, adds refractive surgeon Frederic B. Kremer, M.D., of King of Prussia, Pa.

Glare will often diminish in time. Additional management options include:

• Pilocarpine drops. Patients may use a 0.5 percent concentration (or you can dilute it to 0.25 or 0.125 percent) before a long drive at night or some other event in which they anticipate problems with glare or haloes. "For most patients, it's a very effective way to manage the problem," Dr. Kremer says.

Make sure the patient has had a peripheral retinal exam with scleral depression after the initial surgery to rule out any asymptomatic retinal breaks.

• Contact lenses. Opaque contact lenses can help by creating a pupil with an artificially limited diameter that is smaller than the LASIK zone, Dr. Gurwood says. Patients often resist this option because they look somewhat unnatural.

Rigid contact lenses also are an effective treatment if there is irregular astigmatism, but most patients resist this option. After all, they had refractive surgery so they would not have to wear contact lenses, Dr. Kremer says.

• Phototherapeutic keratectomy. PTK-Biomask can be effective when constant or recurrent corneal surface abnormality causes glare. This may be considered for post-op patients whose best-corrected vision is worse than 20/30 and who have severe haloes and/or ghosting. The surgeon makes a custom mask out of a collagen gel and ablates the mask with an excimer laser. As the beam breaks through the mask, it smoothes the corneal surface and transfers the curvature of the mask's front surface to the cornea, says Dr. Kremer. He is currently performing this technique under an FDA protocol.

Even though treatment options exist, try to avoid the problem by carefully selecting LASIK patients beforehand. Generally, you'll want to avoid LASIK on patients with large pupils, as measured in dim illumination, says optometrist Morris F. Sheffer of Charlotte, N.C. The Colvard pupillometer is an ideal way to measure pupil size.

Dallas optometrist John Potter, with TLC Laser Eye Centers, says larger pupil size does not always result in glare. However, he adds, young women with larger pupils are at greater risk for post-op glare, as are highly myopic patients with very flat corneas.

Educate patients before the procedure about what they might expect afterwards, Dr. Gurwood says.

Question: What should I do if I observe epithelial in-growth in post-LASIK patients?

Answer: In-growth can worsen and lead to complications, so Dr. Sheffer suggests you refer the patient back to the surgeon early on. The surgeon lifts the cap, debrides the epithelium and irrigates the surfaces, and then replaces the cap.

Others say that if the in-growth is small, in the periphery and does not affect vision, you may carefully monitor the patient. These deposits will likely decrease over time, Dr. Kremer says. If the deposits are larger or they affect vision, refer the patient back to the surgeon.

Dr. Potter suggests you monitor patients every few days or once a week. Watch for signs of spread, clumping or nesting of cells with subsequent inflammation, rolling of the edge of the flap, or corneal inflammation. Consider anything larger than 1mm to be a risk. "Left unchecked, epithelial in-growth can cause the corneal tissue to melt as the cells die and become necrotic," Dr. Potter says.