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 SMILE surgery. Although this refractive procedure offers several advantages, such as a smaller incision and no risk of flap-related complications, EI can still occur, and due to the specific nature of the surgical technique, it can be challenging to manage.

In a new study led by Dr. Miao Zhang from Shenzhen Eye Hospital, researchers investigated the mechanisms behind the development of EI and explored effective treatment options. The study, which included four case reports, revealed that the formation of the opaque bubble layer (OBL) during SMILE surgery may create microchannels, that allow epithelial cells to migrate into the corneal stroma and lead to EI. This finding challenges the traditional understanding that EI is primarily caused by trauma to the flap margins.

The team used imaging techniques, including anterior segment optical coherence tomography (AS-OCT), corneal topography, and corneal confocal microscopy, to diagnose and monitor the cases. They found that the location and shape of the OBL closely matched the areas of epithelial ingrowth, suggesting a direct link between OBL formation and EI.

To address this complication, the researchers used sub-flap debridement, a standard procedure in which involves carefully cleaning the epithelial tissue at and around the incision site is carefully cleaned to remove any debris that might contribute to EI. The study reports significant clinical improvements in all four cases, with no recurrence of EI observed during follow-up.

“Our findings suggest that the microchannels created by OBL during surgery may play a crucial role in the development of EI,” said Dr. Zhang. “This highlights the importance of precise surgical techniques and effective postoperative management to prevent this complication.”

The study also emphasizes the need for preventive measures to minimize OBL formation during SMILE surgery. These measures include the careful use of anaesthesia to prevent eye movement, accurate positioning of the suction cone, and controlled suction. Additionally, post-operative use of topical corticosteroids and bandage contact lenses can promote healing and reduce the risk of recurrence.

This novel research provides valuable insights into the prevention and management of corneal epithelial ingrowth following SMILE surgery and highlights the need for continued advancements in surgical protocols and technology to improve patient outcomes.