Corneal ectasia (also called "kerectasia" or "keratectasia") is an infrequent but serious complication of LASIK surgery.
If the laser removes too much tissue during LASIK or the flap made too deep, the structure of the cornea can be weakened. This weakening can cause the cornea to bulge forward in an irregular fashion, causing increasing astigmatism and distorted vision that cannot be corrected with eyeglasses, contact lenses, or a LASIK enhancement procedure. In its most extreme form, treatment of ectasia may require a corneal transplant.
A corneal transplant is performed by replacing damaged central corneal tissue with healthy tissue from a donor. Corneal transplants are performed routinely in the United States, however this surgery still has a certain amount of risk attached to it.
Patients with thin corneas have a higher risk of developing ectasia. Keratectasia after LASIK is similar to a condition that afflicts 1 in 2,000 people, called keratoconus.
Corneal Crosslinking for Ectasia Therapy
Patients with keratectasia should not have additional eye surgery that removes corneal tissue. Rigid gas permeable (RGP) contact lenses are often the treatment of choice for restoring good vision. A new treatment to strengthen the cornea called CXL or corneal crosslinking is showing promise in controlling corneal ectasia. The non-invasive procedure consists of placing riboflavin eye drops on the eye and activating it with UV light. The activated riboflavin penetrates the cornea and strengthens the corneal tissue, stabilizing the corneal shape.
In some cases, after the cornea has been stabilized with CXL, the eye can be treated with topography-guided PRK to bring the cornea into a more normal shape to improve vision.
As eye doctors have learned more about ectasia, better screening methods have been developed to assess a person's risk for LASIK-induced keratectasia during preoperative exams. Also, there appears to be less risk of ectasia with PRK, epi-LASIK and LASEK, compared to LASIK.