Abstract
PurposeThe goal of this study was to compare small incision lenticule extraction (SMILE) with femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for treating myopia.MethodsThe CENTRAL, EMBASE, PubMed databases and a Chinese database (SinoMed) were searched in May of 2016. Twelve studies with 1,076 eyes, which included three randomized controlled trials (RCTs) and nine cohorts, met our inclusion criteria. The overall quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group framework. Data were extracted and analysed at three to six months postoperatively. Primary outcome measures included a loss of one or more lines of best spectacle corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA) of 20/20 or better, mean logMAR UCVA, postoperative mean spherical equivalent (SE) and postoperative refraction within ±1.0 D of the target refraction. Secondary outcome measures included ocular surface disease index (OSDI), tear breakup time (TBUT) and Schirmer’s 1 test (S1T) as dry eye parameters, along with corneal sensitivity.ResultsThe overall quality of evidence was considered to be low to very low. Pooled results revealed no significant differences between the two groups with regard to a loss of one or more lines in the BSCVA (OR 1.71; 95% CI: 0.81, 3.63; P = 0.16), UCVA of 20/20 or better (OR 0.71; 95% CI: 0.44, 1.15; P = 0.16), logMAR UCVA (MD 0.00; 95% CI: -0.03, 0.04; P = 0.87), postoperative refractive SE (MD -0.00; 95% CI: -0.05, 0.05; P = 0.97) or postoperative refraction within ±1.0 D of the target refraction (OR 0.78; 95% CI: 0.22, 2.77; P = 0.70) within six months postoperatively. The pooled analysis also indicated that the FS-LASIK group suffered more severely from dry eye symptoms (OSDI; MD -6.68; 95% CI: -11.76, -2.00; P = 0.006) and lower corneal sensitivity (MD 12.40; 95% CI: 10.23, 14.56; P < 0.00001) at six months postoperatively.ConclusionsIn conclusion, both FS-LASIK and SMILE are safe, effective and predictable surgical options for treating myopia. However, dry eye symptoms and loss of corneal sensitivity may occur less frequently after SMILE than after FS-LASIK.
Highlights
Laser-assisted in situ keratomileusis (LASIK) has been the standard refractive surgery used for treating myopia since the 1990s[1]
Pooled results revealed no significant differences between the two groups with regard to a loss of one or more lines in the best spectacle corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA) of 20/20 or better, logMAR UCVA (MD 0.00; 95% confidence interval (CI): -0.03, 0.04; P = 0.87), postoperative refractive spherical equivalent (SE) (MD -0.00; 95% CI: -0.05, 0.05; P = 0.97) or postoperative refraction within ±1.0 D of the target refraction within six months postoperatively
The pooled analysis indicated that the FS-LASIK group
Summary
Laser-assisted in situ keratomileusis (LASIK) has been the standard refractive surgery used for treating myopia since the 1990s[1]. One of the critical steps in this procedure is the creation of a corneal flap[2], which is followed by corneal ablation using a separate excimer laser. This corneal flap is traditionally created by mechanical microkeratomes (MK)[3], and the application of femtosecond laser increases predictability of flap depth, allowing LASIK surgery to be safer and more precise. With the introduction of the femtosecond laser (VisuMax, Carl Zeiss Meditec AG) in 2006, a new method of intrastromal keratomileusis, small incision lenticule extraction (SMILE), emerged[4]. A metaanalysis of the existing randomized controlled trials (RCTs) and cohorts using SMILE and FS-LASIK to correct myopia was performed
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