The Impact of Small Incision Lenticule Extraction on the Biomechanical Properties of the Cornea: A Review

Recently, due to advancements in keratorefractive surgery, small incision lenticule extraction (SMILE) has become increasingly recognized as a top surgical technique for treating refractive defects. The technology employs a femtosecond laser to precisely incise a stromal lenticule, which is subsequently extracted through a small incision, thereby preserving the front and most rigid regions of the cornea with minimal damage. Despite the widespread recognition of SMILE for its safety, biomechanical stability, effectiveness, and predictability, studies consistently document occurrences of postoperative keratectasia and a notable reduction in corneal biomechanical stability following the surgery. Hence, it is imperative to conduct further research on the several parameters linked to corneal biomechanical stability following SMILE. This narrative review comprehensively synthesizes the current literature on this topic and examines the literature on the evaluation of corneal biomechanics before and after SMILE. It provides a thorough review of the fundamental principles of corneal biomechanics, measurement techniques, the impact of various keratorefractive surgeries on corneal biomechanics, and the mechanisms through which SMILE affects corneal biomechanics.