Abstract
Purpose :
The femtosecond laser has some theoretical advantages over the use of a mechanical microkeratome in LASIK, these advantages are controversial in the clinical setting. We performed a systematic review to compare the effectiveness and safety of femtosecond laser versus mechanical microkeratome in LASIK for myopia.
Methods :
We included randomized controlled trials comparing femtosecond laser-assisted LASIK versus mechanical microkeratome-assisted LASIK. Study inclusion was not restricted on the basis of language or publication status. The electronic searches were performed by the Cochrane Eyes and Vision (CEV) Information Specialist using electronic databases for randomized controlled trials. The studies were assessed against pre specified inclusion criteria, evaluated the risk of bias using the "“Cochrane Risk of Bias Assessment Tool” and extracted data from the selected studies. We calculated mean difference (MD) with 95% confidence intervals (CIs) for continuous measures and risk ratios (RRs) with the corresponding 95% CIs for dichotomous outcomes to estimate treatment effects. The full protocol was registered at the Cochrane Library.
Results :
The electronic searches identified 4,409 references, after the selection process, a total of 9 studies, representing 550 eyes, were included in the review. The MDs of the mean uncorrected visual acuity after surgery, best corrected visual acuity after surgery and mean spherical equivalent of refractive error after surgery were 0 (-0.03, 0.02), -0.01 (-0.04, 0.02) and 0.20 (0.13, 0.26) respectively. The RRs of the proportion of eyes within 0.5 diopters of target refraction after surgery (Figure 1) and diffuse lamellar keratitis (Figure 2) were 0.91 (0.83, 1.00) and 0.27 (0.10, 0.78).
Conclusions :
The use of femtosecond laser to create the corneal flap in LASIK is related to a higher risk of producing diffuse lamellar keratitis, and there is no significant benefits in visual outcomes compared with the mechanical microkeratome. There are few studies in the literature that focus on patient oriented outcomes and report adverse events, therefore a significant uncertainty in efficacy and accuracy between LASIK with femtosecond laser or mechanical microkeratome exist. Future clinical trials should focus on reporting patient oriented outcomes using a standardized protocol of outcomes and follow-up intervals.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.