Re-treatment after laser in situ keratomileusis for correction of myopia and myopic astigmatism.

Aim: To evaluate the results of laser in situ keratomileusis (LASIK) re-treatment for under correction or regression after primary LASIK procedures for myopia and myopic astigmatism.

Methods: A prospective evaluation of 360 consecutive LASIK-treated eyes, for myopia and/or myopic astigmatism, 32 eyes of 34 patients were retreated and followed at 3, 6 and 12 months post-retreatment. Re-treatment was performed by lifting the original flap after cutting the epithelium around the flap edge with a fine needle. Standard ablation was performed based on the patient's residual refraction.

Results: 9.4% of eyes required retreatment. Prior to re-treatment the mean manifest spherical equivalent (SE) was -0.99 (SD 1.48) D (range -0.75 to -2.63). The mean sphere was -0.79 (1.20) D (range -2.50 to -0.50), and the mean cylinder was -0.90 D (1.14) D (from -2.75 to 1.25). At 1-year follow-up 56% of the eyes were within +/-0.50 D SE, and 78% were within +/-1.00 D SE. 78% of the eyes examined at 1-year post-re-treatment managed unaided vision of 6/9 or better. Peripheral epithelial ingrowth not requiring treatment developed in two eyes. Second re-treatment for regression was performed in one eye. A significant correlation was found between the refractive regression and each of the following: preoperative refraction, attempted correction and ablation depth.

Conclusion: LASIK re-treatment for residual myopia, by lifting the original flap, is an effective option. Refractive results are fairly predictable, and refraction stabilises by 3 months after re-treatment. Lifting the corneal flap after cutting the epithelium on the flap edges is easy to perform and has a very low incidence of epithelial ingrowth.