Small incision corneal refractive surgery using the small incision lenticule extraction (SMILE) procedure for the correction of myopia and myopic astigmatism: results of a 6 month prospective study

Aim This 6 month prospective multi-centre study evaluated the feasibility of performing myopic femtosecond lenticule extraction (FLEx) through a small incision using the small incision lenticule extraction (SMILE) procedure. Design Prospective, non-randomised clinical trial. Participants Ninety-one eyes of 48 patients with myopia with and without astigmatism completed the final 6 month follow-up. The patients' mean age was 35.3 years. Their preoperative mean spherical equivalent (SE) was -4.75 +/- 1.56 D. Methods A refractive lenticule of intrastromal corneal tissue was cut utilising a prototype of the Carl Zeiss Meditec AG VisuMax femtosecond laser system. Simultaneously two opposite small 'pocket' incisions were created by the laser system. Thereafter, the lenticule was manually dissected with a spatula and removed through one of incisions using modified McPherson forceps. Main outcome measures Uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity (BSCVA) after 6 months, objective and manifest refraction as well as slit-lamp examination, side effects and a questionnaire. Results Six months postoperatively the mean SE was -0.01 D +/- 0.49 D. Most treated eyes (95.6%) were within +/- 1.0 D, and 80.2% were within +/- 0.5 D of intended correction. Of the eyes treated, 83.5% had an UCVA of 1.0 (20/20) or better, 53% remained unchanged, 32.3% gained one line, 3.3% gained two lines of BSCVA, 8.8% lost one line and 1.1% lost >= 2 lines of BSCVA. When answering a standardised questionnaire, 93.3% of patients were satisfied with the results obtained and would undergo the procedure again. Conclusion SMILE is a promising new flapless minimally invasive refractive procedure to correct myopia.