Study examines corneal epithelial ingrowth after small incision lenticule extraction surgery

This study identifies mechanisms of epithelial growth post-SMILE surgery and suggests preventive and treatment measures, including subflap debris removal, to address corneal epithelial ingrowth. (Image credit: MedComm-Future Medicine)

A team of researchers in China has examined corneal epithelial ingrowth (EI), a rare but significant complication following SMILE surgery.

While this refractive procedure can offer 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 the study, which was led by Dr. Miao Zhang from Shenzhen Eye Hospital, and Ieng Chong, part of the Faculty of Innovation Engineering (FIE), Macao University of Science and Technology (MUST), in Macao, China, researchers looked at the mechanisms behind the development of EI and explored effective treatment options.¹

The study, which included 4 case reports, revealed that the development of the opaque bubble layer (OBL) during SMILE surgery could 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.

According to the study, the researchers 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.²

The researchers addressed the complication by utilizing 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.¹

“Our findings suggest that the microchannels created by OBL during surgery may play a crucial role in the development of EI,” Zhang said. “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 anesthesia 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.¹

The researchers noted in the study they explored the possible mechanisms of EI, proposing that it may involve the formation of OBL-induced microchannels in Bowman's layer during surgery, which could facilitate epithelial cell migration to the surface.

“To verify this mechanism, extensive clinical observations and animal experiments are necessary,” they wrote. “Additionally, we hope that advancements in noninvasive vo imaging technologies will allow for better visualization of the corneal ultramicroscopic structure, thereby providing stronger evidence to support our hypothesis.”

The researchers concluded their research provides 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.¹

References

1. Miao Zhang, Ieng Chong, Xiaoniao Chen, Juan Yang, Linleng Cheng, Zonghui Yan. Corneal epithelial ingrowth after small incision lenticule extraction surgery: Insights from a case series and mechanistic studies. Medcom Future Medicine. Published September 18, 2024. Accessed September 26, 2024. DOI: https://doi.org/10.1002/mef2.99

2. Corneal epithelial ingrowth after small incision lenticule extraction surgery: Insights from a case series and mechanistic studies. EurekAlert! Published September 26, 2024. Accessed September 27, 2024. https://www.eurekalert.org/news-releases/1059313