To analyze the incidence and clinical course of epithelial ingrowth after laser in situ keratomileusis (LASIK) using a femtosecond laser.

We retrospectively evaluated the results of 1158 eyes of 581 patients who received LASIK with the flap created by a femtosecond laser from February 2006 to March 2009 at our institute. We investigated the incidence and clinical course of LASIK in which the flap was created by a femtosecond laser.

Epithelial ingrowth was first detected one week after surgery in 12 (57%) of 21 eyes and within one month in 19 eyes (90%). Epithelial ingrowth was localized most commonly near the temporal and nasal flap edge in 12 eyes (57%). In two eyes (9.5%), an isolated ingrowth mass was located in the pupillary area. The development of more than 2.0 mm of epithelial ingrowth was observed in three eyes (0.25%). Among 28 eyes with loose epithelium or epithelial detachment during surgery, epithelial ingrowth was observed in six eyes (21.4%) compared with 15 (1.32%) of 1130 eyes without loose epithelium or epithelial detachment. Therefore, epithelial detachment during surgery was significantly associated with epithelial ingrowth ( p = 0.00).

In LASIK in which the flap is created by a femtosecond laser, damage to the epithelial layer increases the chances of epithelial ingrowth. Therefore, avoiding epithelial defects with a gentle maneuver is needed to reduce the chance of epithelial ingrowth during surgery.