Comparison of clinical outcomes between 'on-flap' and 'off-flap' epi-LASIK for myopia: a meta-analysis.

OBJECTIVE To examine possible differences in clinical outcomes between off-flap and on-flap epipolis laser in situ keratomileusis (epi-LASIK) for myopia. METHODS Pertinent studies were selected by extensive searches. A total of 9 studies reporting on a total of 958 eyes were included in the present meta-analysis. Statistical analysis was performed using RevMan 5.0 software. RESULTS There were no significant differences in the final refractive spherical equivalent (p = 0.38), manifest refractive spherical equivalent within ±0.50 D of the target (p = 0.76), final uncorrected visual acuity (p = 0.90), loss of ≥1 line of best spectacle-corrected visual acuity (p = 0.99), and corneal haze at 3 months postoperatively (p = 0.96) or more than 6 months (p = 0.64). More patients felt severe pain in the on-flap group than in the off-flap group, although this finding was not statistically significant (p = 0.05). However, off-flap epi-LASIK had a better mean uncorrected visual acuity at 3 days (p = 0.04) and 5 days (p = 0.01), and faster re-epithelialization (p < 0.00001) after surgery. CONCLUSIONS According to the available data, off-flap and on-flap epi-LASIK had equal visual and refractive outcomes for the treatment of myopia. Off-flap epi-LASIK had more rapid re-epithelialization and visual recovery compared to on-flap epi-LASIK.