Compensation Of Astigmatism By Accommodation After Small Incision Lenticule Extraction

To analyze compensatory effect of astigmatic accommodation on refractive astigmatism and evaluate the changes of ocular residual astigmatism after small incision lenticule extraction (SMILE) conducted with vector planning

Yonsei University College of Medicine and Eyereum Eye Clinic, Seoul, South Korea.

This was a retrospective case series study of 40 patients (80 eyes) diagnosed with myopia and astigmatism who underwent uneventful SMILE on both eyes between 2017 and 2020. Corneal astigmatism, refractive astigmatism, and ocular residual astigmatism (ORA) were measured using Nidek OPD scan. Visual acuity, manifest refraction, corneal topography, ocular aberration were measured preoperatively and postoperatively.

At 3 months postoperatively, all treated eyes achieved 20/20 or better uncorrected distance visual acuity (UDVA) and 74% of eyes achieved 20/16 or better UDVA. 90% and 86% of all evaluated eyes were above the safety and efficacy cut-off levels, respectively. Astigmatic accommodation measured with OPD scan and vector analysis were 0.24 ± 0.18 D and 0.34 ± 0.27 D, respectively. Linear regression analysis for amount of ORA changes and compensated amount of postoperative refractive astigmatism had statistically significance.

Astigmatic accommodation after myopic astigmatism correction was identifiable after vector planned SMILE and had linear correlation with mitigated postoperative residual astigmatism. Analysis of ORA and extent of astigmatic accommodation provided new insights to enhancing postoperative residual astigmatism correction in SMILE. However, astigmatic accommodation can also act as a confounding factor for the predictability of astigmatism correction with SMILE and further correlation analysis and nomogram adjustment for astigmatism correction is needed.