AIM:To study the outcomes of ReLEx^® small incision lenticule extraction(SMILE)for correction of myopia or myopic astigmatism in terms of visual acuity, contrast sensitivity, aberrations, and dry eye.

METHODS: In this prospective, non-randomized clinical study, done at Nethradhama Super Speciality Eye Hospital, a total of 600 eyes that met the inclusion criteria underwent a thorough preoperative examination, including corrected distance visual acuity(CDVA), contrast sensitivity, aberrometry, and dry eye assessment. VisuMax femtosecond laser system was used to perform SMILE. Patients were followed up on 1, 15d and 3mo. Pre and postoperative uncorrected visual acuity(UCVA), CDVA, aberrations, dry eye, and contrast sensitivity during 3mo of follow-up were recorded. Data analysis was done with the help of a computer using SPSS for Windows Software(version 17.0, SPSS, Inc., New York, USA). A paired t-test was used to test the significance of difference between quantitative variables and Yate's Chi-square test for qualitative variables. P value less than 0.05 denoted a significant relationship.

RESULTS: The study enrolled 600 eyes of 305 patients, of which 10 patients underwent SMILE in 1 eye only due to anisometropia. At 3mo, 98.83% of eyes had attained a UCVA of 20/20 or better. No patient had a loss of CDVA, and 37 eyes(6.17%)showed a gain in 1 line in postoperative CDVA. Postoperative induction of coma and spherical aberrations was minimal. Contrast sensitivity reduced immediate postoperatively(P<0.001)but showed improvement by 3mo, especially at lower spatial frequencies(P=0.43, 0.47, 0.46)

CONCLUSION:Our results demonstrate the high refractive accuracy and safety of ReLEx^® SMILE for the treatment of myopia and myopic astigmatism. Increase in postoperative dryness and aberrations, both accepted drawbacks of any corneal refractive surgery were observed, while decrease in contrast sensitivity was insignificant at lower spatial frequencies.