Corneal epithelial ingrowth after small incision lenticule extraction surgery: Insights from a case series and mechanistic studies

Corneal epithelial ingrowth (EI) is a rare but significant complication following Small Incision Lenticule Extraction (SMILE) surgery. During the procedure, the opaque bubble layer (OBL) formation may create microchannels that disrupt Bowman's layer, providing a pathway for epithelial cells to migrate into the corneal stroma. In this study, we investigated the mechanisms behind EI development and proposed preventive strategies. We analyzed four cases of EI post-SMILE surgery, utilizing anterior segment optical coherence tomography (AS-OCT) and corneal tomography for diagnosis. Preventive measures, including careful anesthetic application and precise suction cone positioning, were employed to minimize OBL formation. Here, we show that subflap debris removal surgery led to significant clinical improvement, with no EI recurrence observed. Our findings suggest that the microchannels created by OBL during surgery may play a crucial role in EI development, challenging previous assumptions that EI is primarily due to trauma at the flap edges. This underscores the importance of precise surgical technique and effective postoperative management. Further research, including clinical studies and advanced imaging, is needed to confirm this proposed mechanism and improve outcomes in refractive surgery. The study highlights the necessity for ongoing advancements in surgical protocols and technology to prevent and manage EI effectively.