Small Incision Lenticule Extraction(SMILE) In Correcting Low Astigmatism:RCT

Objective To investigate the safety,effectiveness,stability and predictability of smile surgery for correction of low astigmatism≤-0.50 D,and whether there is any difference in refractive effect after surgery.Methods This is a randomized controlled trial.A total of150 patients with astigmatism degree≤-0.50 D and undergoing smile surgery were randomly divided into group A(uncorrected astigmatism)and group B(corrected astigmatism).The visual acuity and refractive index were measured before and 1,3,6months after operation.Alpin’s vector analysis was used to evaluate the effect of astigmatism.Results Three months after surgery,86% and 92% of the eyes in group A(non astigmatism group)and group B(corrected astigmatism group)had a visual acuity of20 / 20 or above,respectively;the number of eyes with BCVA unchanged or better than that before operation accounted for 100%;the safety indexes of group A and group B were1.00 and 1.13,respectively.The results of vector analysis of astigmatism showed that there was no significant difference in the evaluation indexes of astigmatism correction effect between the two groups at 1,3 and 6 months after operation,except that there was statistical difference in IOS at 6 months after operation.Conclusion astigmatism ≤-0.50 D with or without correction in SMILE surgery is safe,effective and predictable.There is no significant difference in astigmatism outcome after surgery,it can be considered that astigmatism within-0.50 D not be corrected in SMILE surgery.