LASIK stands for laser-assisted in situ keratomileusis, a common vision correction procedure. During this type of refractive surgery, a flap is created in the cornea, the laser is used to remove tissue from the cornea and the flap is rolled back into place. Certain corneal issues can make it difficult to have a good outcome after the surgery; these conditions can prohibit a patient from being a candidate for LASIK.
Thin Corneas
As noted by the Medical Management Services Group, it is important to have sufficient corneal thickness to have a successful LASIK procedure. Because LASIK surgery requires both a corneal flap and removal of corneal tissue by the laser to correct the vision, there needs to be enough tissue in the cornea to accomplish both parts of the procedure. People with thin corneas may not have enough tissue to create the flap, then to remove enough corneal tissue to correct the vision problem and still have enough cornea left over to keep the shape of the eyeball afterward.
Corneal Scarring
Scars in the cornea may eliminate a patient from being a candidate for LASIK surgery. Scars may interfere with the creation of the flap and the ability to remove tissue with the laser. Previous refractive surgery procedures may have left corneal scarring, depending on the type of procedure used. Previous injuries to the cornea may have scarred the tissue as well.
Dry Eye Syndrome
The Academy of Ophthalmology notes that the presence of dry eyes may prohibit participation in LASIK procedures in its patient guide "Is LASIK for Me?", published in 2008. Development of dry eye symptoms is a common side effect of the LASIK procedure that usually resolves for most patients after a few months as noted in the same publication. For some patients, the dry eye problems can last for a much longer time. If a patient already had severe dry eye symptoms prior to the procedure, the additive effects could make the eye extremely uncomfortable.
Keratoconus
The Eye Surgery Education Council Medical Advisory Board states that the presence of keratoconus precludes LASIK surgery. Keratoconus is a condition in which changes in the collagen in the cornea cause the cornea to thin. By removing corneal tissue with the laser, LASIK surgery also thins the cornea. In patients with keratoconus, LASIK would further weaken an already thin cornea, which could lead to problems. The cornea in these patients may become so damaged that these patients would need a corneal transplant at some point.
