Comparison Of Epithelial And Corneal Aberrations Following Smile For Varying Degrees Of Myopia Correction.

To compare the epithelial and corneal aberrations in patients following SMILE for varying degrees of myopia correction.

Nethradhama superspeciality eye hospital, Bengaluru, India.

This study included age matched subjects undergoing SMILE procedure for varying degrees of myopia. According to the preoperative spherical equivalent (SE), eyes were divided into three groups: high (> -6.1 D ) , moderate (-3.1 D to -6 D ) and low ( < -3 D) myopia. Follow-up visits were conducted at 1 day, 2 weeks and 3 months. Corneal and epithelial aberrations were measured using an OCT based tomographer (MS-39, Costruzione Strumenti Oftalmici,CSO ITALY ) and compared between the three groups.

A total of 150 eyes from 150 patients (n=50 eyes in each group) were analysed. Pre-op SE in low, moderate and high myopia was -7.04 ± 0.91 , -4.37 ± 0.94 and -1.93 ± 0.67 D which reduced to -0.02 ± 0.06 D, -0.014 ± 0.06 D and – 0.03 ± 0.12 D at 3 months, respectively. A significant increase in corneal HOA’s was noted (p =0.00) , which were mainly contributed by coma, irrespective of the degree of myopia. A corresponding increase in the epithelial HOAs was also noted(p = 0.01), which were equally and significantly contributed by increase in epithelial SA and coma(p=0.00). Epithelial HOAs were significantly increased in the high myopia group compared to the other groups (p = 0.01).

Post SMILE procedure, increase in the total corneal aberration was found to be contributed majorly by the epithelium. Within individual aberrations, significant increase in coma was noted which may be attributed to the non-automated, patient controlled fixation based treatment centration.