Development of low laser energy levels in small-incision lenticule extraction: Clinical results, black area, and ultrastructural evaluation

Abstract

Purpose:To evaluate the outcomes of 4 low laser energy levels after small-incision lenticule extraction (SMILE) surgery.Setting:Zhongshan Ophthalmic Center, Guangzhou, China.Design:Prospective randomized clinical trial.Methods:This study evaluated consecutive patients who had SMILE to correct myopia or myopia with astigmatism. Eyes were placed into groups based on the laser energy used during surgery (ie, 105 nJ, 110 nJ, 115 nJ, or 120 nJ). All patients had a thorough ophthalmic examination preoperative and at 4 timepoints over 3 months postoperatively. Black areas and surface regularity of the extracted lenticules were observed and evaluated qualitatively and quantitatively.Results:The study comprised 124 eyes of 62 patients (40 women, 22 men), with 31 eyes in each laser energy group. The incidence of black areas was 45.16% (14 of 31 eyes), 12.90% (4 of 31 eyes), 16.13% (5 of 31 eyes), and 12.90% (4 of 31 eyes) for 105 nJ, 110 nJ, 115 nJ, and 120 nJ, respectively. The mean time for lenticule creation was the longest in the 105 nJ group (P =.015). The greatest increase in corneal thickness postoperatively occurred with 105 nJ (P