A 6-month longitudinal and comparative study of corneal biomechanical properties after SMILE with two different optical zone sizes

The independent effect of a 0.2 mm difference in optical zone size on corneal biomechanical properties after SMILE appears to be limited. After comprehensive statistical adjustment, the results suggest that preoperative anatomical and surgical parameters, especially corneal stromal ablation depth, are the primary drivers of the postoperative biomechanical response, rather than the minor difference in OZ size itself. This study underscores the importance of confounder adjustment in refractive surgery research and suggests that maximizing the residual stromal bed may be more critical for maintaining corneal biomechanical integrity than fine-tuning the optical zone diameter.