[Clinical outcomes of SMILE Xtra for myopia correction].

Abstract

Purpose: This study assesses the treatment outcomes of patients with thin corneas and/or borderline corneal topography who underwent combined refractive surgery using the SMILE Xtra technique.

Material and methods: The study included 53 patients (105 eyes) with myopia and a risk of developing keratectasia according to the Randleman criteria. All patients underwent prophylactic crosslinking following the SMILE procedure by introducing riboflavin solution into the corneal pocket, followed by ultraviolet irradiation according to the SUB-400 protocol with additional acceleration. The results were evaluated using data from Scheimpflug analyzer, analysis of corneal biomechanical properties, optical coherence tomography (OCT), and standard ophthalmological examinations. Follow-up lasted up to 12 months.

Results: The preoperative spherical equivalent of refraction was -4.09±1.30 D, and postoperative measurements on day 1, day 7, and at 1, 3, 6, and 12 months were: -0.08±0.64; 0.1±0.53; 0.2±0.48; 0.05±0.52; -0.29±0.47; 0.1±0.49 D, respectively. On day 1, uncorrected visual acuity (UCVA) increased to 0.78±0.17, rising to 0.94±0.11 by day 7, and remained stable throughout the follow-up. Mean keratometry values preoperatively were 44.32±1.3 D, and 40.89±1.65 D on day 1, with no statistically significant changes throughout the follow-up. Central corneal thickness decreased from 528.30±28.71 μm preoperatively to 459.32±28.92 μm on day 1 and 440.54±29.12 μm on day 7. Patient complaints of blurred vision on day 1 were associated with mild corneal edema due to residual riboflavin and energy load from UV treatment; these symptoms resolved by day 7. No regression of refractive results or keratectasia was observed throughout the follow-up period.

Conclusion: SMILE Xtra can be used for myopia correction in cases with an increased risk of postoperative keratectasia in patients with thin corneas and/or borderline corneal topography readings.