Visual and keratometric outcomes in eyes undergoing small incision lenticule extraction for compound myopic astigmatism

Abstract

Context The use of small incision lenticule extraction (SMILE) for compound myopic astigmatism has been subject to experimentation in the recent years. Furthermore, examination of corneal alterations has revealed conflicting conclusions, which could be attributable to demographic variation. Aims The aim of this study was to measure visual and keratometric efficacy of SMILE and correlate spherical equivalent (SE) decrements to keratometric alterations. Settings and design This was a prospective nonrandomized study. Thirty eyes of 15 patients were included in the study. Preoperative assessment included oculus Pentacam analysis. Patients were followed-up for up to 3 months, after which tomography was repeated. Statistical analysis used Descriptive statistics, t test, and linear regression analysis were carried out. Results There was a statistically significant improvement in postoperative uncorrected distance visual acuity and SE and a statistically significant change in Q value (P<0.001). The mean residual SE postoperatively was −0.14 D. A highly statistically significant negative correlation existed between SE difference and mean K difference with r=−0.980 and P value less than 0.001, and a highly statistically significant positive correlation existed between SE difference and Q value difference, with r=0.787 and P value less than 0.001. Conclusion SMILE is a safe and effective technique to correct cases with myopic astigmatism with an SE of up to −10 D, and a predictable positive correlation could be established between decrements in SE and decrements in anterior corneal steepening.

Keywords

• keratometry
• Pentacam
• refractive correction
• small incision lenticule extraction