Factors Affecting Visual Outcome after Small Incision Lenticule Extraction (SMILE) Pro

To report the factors affecting visual outcomes after small incision lenticule extraction (SMILE) in eyes treated with the Visumax 800.

This is a retrospective study with cross-sectional design of eyes underwent SMILE Pro using Visumax 800 at Jakarta Eye Center. Patients ≤40 years old with a corrected distance visual acuity of >20 / 25, manifest refractive spherical equivalent ≤10.0 diopters (D), and cylinder refraction <5.0 D were included. Evaluation of visual outcomes was conducted at 1 day and 1 month postoperatively.

A total of 258 eyes from 132 patients were analyzed. Among the total, 94% achieved an uncorrected distance visual acuity (UDVA) of 20 / 20 at 1 month postoperatively. Of the eyes with high myopia, 81% achieved a UDVA of 20 / 20, followed by 97% and 99% in moderate and low myopic eyes, respectively. Spherical equivalent refraction (r = 0.273, p < 0.01), optic zone (OZ; r = 0.260, p < 0.01), cap thickness (r = 0.209, p < 0.01), and residual stromal thickness (RST; r = 0.256, p < 0.01) showed a significant but weak correlation with UDVA at 1 month postoperatively. There is increasing risk to get <20 / 20 UDVA in right eyes (odds ratio [OR], 3.101; p < 0.045), eyes with high myopia (OR, 9.964; p < 0.01), 100-μm cap thickness (OR, 4.578; p < 0.01), ≤6 mm OZ (OR, 10.556; p < 0.01), and <300-μm RST (OR, 9.100; p < 0.01) at 1 month postoperatively.

SMILE Pro results in promising visual outcome in early postoperative period. Patients with low to moderate myopia have better visual outcomes than those with high myopia. A small OZ, thin cap thickness, and low RST could increase the risk of not achieving the maximum visual outcome after SMILE. A prospective study with a longer follow-up period that includes comprehensive variables is needed to fully understand the factors affecting visual acuity after SMILE.