In this prospective study, researchers compared the early visual recovery of patients undergoing small-incision lenticule extraction (SMILE) and laser in situ keratomileusis (LASIK).
Study design
Researchers consented 46 patients (sphere 1.0 to 8.0 D) scheduled to undergo bilateral SMILE (n=23) or LASIK (n=23). Contrast sensitivity, objective scatter index (OSI) and patient-reported quality of vision (QoV) were evaluated 1, 7 and 30 days after surgery.
Outcomes
Postoperative contrast sensitivity was better in the LASIK group compared with the SMILE group at day 1 and day 7 (P=0.014 and P=0.001, respectively), but the difference was no longer significant at 1 month. Eyes in the LASIK group had a better OSI at postoperative day 1 (P=0.036). There were no differences in uncorrected distance visual acuity, efficacy or safety at any timepoints.
Patients in the SMILE cohort reported worse quality of vision at day 7 (P=0.010) and had more visual symptoms, including trouble focusing, halos and fog during the first postoperative week. There were no differences in visual symptoms at 1 month.
The overall satisfaction score, however, was very good (>4 on a scale of 1 to 5) and did not differ between the 2 groups at any timepoint.
Limitations
The study could have included preoperative questionnaires and OSI to allow for a better comparison of the outcomes. The SMILE parameters used in this study were different compared with what is available in the United States. Although this study did not compare SMILE and LASIK complications, more studies will need to be performed to demonstrate how to manage the nuances of each. This study did not address surgical learning curves and laser optimization.
Clinical significance
Theoretically, many patients may benefit from SMILE because it conserves the biomechanical stability of the anterior cornea and preserves the subbasal nerve plexus, reducing risk of dry eye. This, combined with the knowledge that overall patient satisfaction was the same for LASIK and SMILE, could influence a surgeon’s choice on the appropriate refractive procedure for a patient. However, the visual recovery for SMILE is slower. Appropriate expectation management is therefore of paramount importance.