Eyes that have undergone LASIK eye surgery with the corneal flap created with a femtosecond laser may be less likely to develop epithelial ingrowth if an enhancement (re-treatment) surgery is needed, according to a study published last month in Journal of Refractive Surgery.
Researchers in Indianapolis, Ind. reviewed the results of 272 consecutive LASIK enhancements performed by a single surgeon over a 4-year period, with the objective of identifying eyes that developed clinically significant epithelial ingrowth after the enhancement procedure.
Epithelial ingrowth is a LASIK complication where cells from the outer surface of the cornea (epithelium) get trapped or migrate under the LASIK flap and continue to multiply. Epithelial ingrowth is considered clinically significant if it causes either discomfort or vision problems and requires the refractive surgeon to re-lift the flap and remove the epithelial cells from the flap interface.
Re-lifting the flap during a LASIK enhancement can cause flap defects that increase the likelihood of epithelial ingrowth.
Among the eyes in the study, enhancements were performed on 132 eyes that had flaps created with a mechanical microkeratome in the initial LASIK surgery, and on 140 eyes that had flaps created with a femtosecond laser.
The same technique was used to lift the flap in all enhancement procedures, regardless of the method of flap creation in the original LASIK procedure.
Analysis of the data revealed:
- Among eyes with microkeratome-created flaps, epithelial ingrowth was identified in 11 eyes (8.3 percent) after enhancement, and 8 eyes (6.1 percent) required surgical intervention.
- Among eyes with femtosecond laser-created flaps, epithelial ingrowth was identified in 2 eyes (1.4 percent) after enhancement, and neither eye required surgical intervention.
The researchers concluded that eyes treated with bladeless LASIK flaps may be less likely to develop epithelial ingrowth after a LASIK enhancement procedure when compared with eyes with LASIK flaps created with a mechanical microkeratome.
They also said the difference in the rate of epithelial ingrowth may be related to the geometry of the flap edge. (Laser-created flaps typically have a 90-degree edge, whereas microkeratome-created flaps have a low-angle “knife” edge.)
[DISCLOSURE: One of the authors of this study is a consultant for Abbott Medical Optics (Santa Ana, Calif.), the manufacturer of IntraLase femtosecond lasers.]
SOURCE: Influence of original flap creation method on incidence of epithelial ingrowth after LASIK retreatment. Journal of Refractive Surgery. November 2009.