Learning Curve of Small Incision Lenticule Extraction: Challenges and Complications.

PURPOSE: To describe the intraoperative complications observed during the initial learning curve of small incision lenticule extraction (SMILE) and their management.

METHODS: Prospective evaluation of 100 consecutive eyes (50 patients) undergoing SMILE was performed at an apex tertiary care ophthalmic center. Patients older than 18 years with a stable refractive error ranging from -1.0 to -10.0 D myopia and up to 3.0 D astigmatism were included. Any intraoperative complications and their management were noted. Postoperative examination including visual acuity was performed on day 1, 1 week, and 1 month.

RESULTS: Intraoperative difficulties observed in the initial 100 eyes included suction loss (2%), black spots (11%), opaque bubble layer (19%), epithelial defect (2%), and difficult lenticule extraction (9%). Difficult lenticule dissection and extraction was the most surgically challenging step and resulted in posterior stromal damage, anterior cap tear (1%), side-cut tears (4%), partially retained lenticule (1%), and completely retained lenticule (2%). Its incidence decreased from 16% (8/50) in the initial 50 cases to 2% (1/50) in the next 50 cases. Two eyes with completely retained lenticule were re-treated with flap-based excimer laser ablation after 3 months. Optimal visual and anatomical outcomes could be achieved, and no sight-threatening complication was observed in any case.

CONCLUSIONS: The learning curve of SMILE is surgically challenging. Lenticule dissection and extraction is the most difficult step and leads to a multitude of complications. Most complications that result in delayed visual recovery are observed in the initial 50 cases.