Small-incision lenticule extraction versus femtosecond lenticule extraction for myopic: a systematic review and Meta-analysis.
OBJECTIVE
To examine differences in efficacy, accuracy, safety, aberrations and corneal biomechanical between Small incision lenticule extraction (SMILE) and femtosecond lenticule extraction (FLEx) for myopia.


METHODS
Comprehensive studies were conducted on the PubMed, MEDLINE, EMBASE, and Cochrane Controlled Trials Register before 31 July, 2015. Meta-analyses were performed on the primary outcomes [loss of ≥2 lines of corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA) ≥20/20, spherical equivalent (SE) within ±0.50 diopters (D), final refractive SE], secondary outcomes were high-order aberrations (HOAs) and corneal biomechanical [central corneal thickness (CCT), corneal hysteresis (CH) and corneal resistance factor (CRF)].


RESULTS
Seven trials describing a total of 320 eyes with myopia were included in this Meta-analysis. No significant differences were found in the efficacy [UDVA weighted mean difference (WMD) -0.01; 95%CI: -0.04 to 0.01;P=0.37, UDVA ≥20/20, OR 1.49; 95%CI: 0.78 to 2.86;P=0.23], accuracy (SE WMD -0.03; 95%CI: -0.12 to 0.07;P=0.58, SE within ±0.5 D OR 1.25; 95%CI: 0.34 to 4.65;P=0.74), HOAs (WMD -0.04; 95%CI: -0.09 to 0.01;P=0.14) and CCT WMD 1.83; 95%CI: -7.07 to 10.72;P=0.69, CH WMD -0.01; 95%CI: -0.42 to 0.40;P=0.97, CRF WMD 0.17; 95%CI: -0.33 to 0.67;P=0.50) in the last fellow-up. But for safety, FLEx may achieve fewer CDVA lost two or more two lines (OR 11.11; 95%CI: 1.27 to 96.86;P=0.03) than SMILE, however CDVA (WMD 0.00; 95%CI: -0.03 to 0.02;P=0.77) is similar.


CONCLUSIONS
SMILE and FLEx are comparable in terms of both efficacy, accuracy, aberrations and corneal biomechanical measures in the follow-up, but FLEx seems to be better in safety measures. The results should be interpreted cautiously since relevant evidence is still limited, although it is accumulating. Further large-scale, well-designed randomized controlled trials are urgently needed.
Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
Jia-Song
JS
Wang
Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
Hua-Tao
HT
Xie
Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
Ye
Y
Jia
Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
Ming-Chang
MC
Zhang
Meta-analysis; femtosecond lenticule extraction; myopia; small-incision lenticule extraction