Small-incision lenticule extraction yielded higher corneal sensitivity, better tear breakup time and less dry eye than femtosecond LASIK, according to a meta-analysis.
The study authors searched the Cochrane Central Register of Controlled Trials, PubMed and the Embase database for prospective comparative studies published between 2000 and 2016. Five trials were selected.
Studies were chosen if SMILE and femtosecond LASIK were performed to correct myopia and myopic astigmatism, with a minimum follow-up of 6 months. LASIK procedures with a microkeratome-created flap were excluded from the meta-analysis. Prospective randomized or non-randomized controlled clinical trials were included; retrospective controlled clinical trials and comparative cohort analyses were excluded.
Schirmer test scores, tear breakup time, ocular surface disease index, tear osmolarity, corneal sensitivity and corneal subbasal nerve density were compared for the two procedures.
Schirmer scores and tear osmolarity were similar between the SMILE and LASIK groups.
Tear breakup time was significantly greater in the SMILE group than in the LASIK group (P = .004 at 1 month and P = .02 at 6 months).
OSDI scores were significantly better in the SMILE group than in the LASIK group at 6 months (P = .0008).
Corneal sensitivity was significantly greater in the SMILE group at 1 month (P < .00001) and 6 months (P < .0001).
Corneal subbasal nerve density was significantly higher in the SMILE group than in the LASIK group at 1 month (P = .01).
“It can be assumed from this meta-analysis that the SMILE procedure has fewer negative impacts on the ocular surface and corneal innervation than does [femtosecond] LASIK,” the study authors said. – by Matt Hasson
Disclosure: The authors report no relevant financial disclosures.