Learning Curve of Small Incision Lenticule Extraction: Challenges and Complications

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

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.

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.

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.