Applying Information Gain to Explore Factors Affecting Small-Incision Lenticule Extraction: A Multicenter Retrospective Study

Shuang Liang; Shufan Ji; Xiao Liu; Min Chen; Yulin Lei; Jie Hou; Mengdi Li; Haohan Zou; Yusu Peng; Zhixing Ma; Yuanyuan Liu; Vishal Jhanji; Yan Wang

doi:10.3389/fmed.2022.837092

Applying Information Gain to Explore Factors Affecting Small-Incision Lenticule Extraction: A Multicenter Retrospective Study

Front Med (Lausanne). 2022 May 3:9:837092. doi: 10.3389/fmed.2022.837092. eCollection 2022.

Authors

Shuang Liang¹, Shufan Ji², Xiao Liu², Min Chen³, Yulin Lei⁴, Jie Hou⁴, Mengdi Li¹, Haohan Zou¹, Yusu Peng³, Zhixing Ma⁴, Yuanyuan Liu⁵, Vishal Jhanji⁶, Yan Wang^{1

7}

Affiliations

¹ Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
² School of Computer Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing, China.
³ Qingdao Eye Hospital, Shandong First Medical University, Qingdao, China.
⁴ Jinan Mingshui Eye Hospital, Jinan, China.
⁵ Department of Health Statistics, College of Public Health, Tianjin Medical University, Tianjin, China.
⁶ Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.
⁷ Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Tianjin, China.

Abstract

Purpose: This retrospective study aimed to identify the key factors influencing postoperative refraction after small-incision lenticule extraction (SMILE) using information gain.

Methods: This study comprised 2,350 eyes of 1,200 patients who underwent SMILE using a Visumax 500-kHz femtosecond laser (Carl Zeiss Meditec AG) in three ophthalmic centers: Tianjin Eye Hospital (center A), Jinan Mingshui Eye Hospital (center B), and Qingdao Eye Hospital (center C). Anterior segment features, including corneal curvature and central corneal thickness (CCT), were obtained from Pentacam HR (Oculus, Wetzlar, Germany). Information gain was calculated to analyze the importance of features affecting postoperative refraction.

Results: Preoperative and postoperative mean spherical equivalent (SE) refraction were -5.00 (-6.13, -3.88) D and 0.00 (-0.25, 0.13) D, respectively. None of the patients lost more than two lines of corrected distance visual acuity. The safety index was 1.32 ± 0.24, 1.03 ± 0.08, and 1.13 ± 0.16 in centers A, B, and C, respectively. The efficacy index was 1.31 ± 0.25, 1.02 ± 0.08, and 1.13 ± 0.17 in centers A, B, and C, respectively. At least 95% of the eyes were within ±1.00 D of the attempted correction. Postoperative refraction was related to preoperative spherical diopter refraction (r = 0.369, p < 0.001), preoperative SE (r = 0.364, p < 0.001), maximum lenticule thickness (r = -0.311, p < 0.001), preoperative uncorrected distance visual acuity (r = 0.164, p < 0.001), residual stromal thickness (r = 0.139, p < 0.001), preoperative mean anterior corneal curvature (r = -0.127, p < 0.001), preoperative flattest anterior corneal curvature (r = -0.122, p < 0.001), nomogram (r = -0.100, p < 0.001) and preoperative CCT (r = -0.058, p = 0.005).

Conclusions: SMILE was considered a safe and effective procedure for correcting myopia. Based on information gain, postoperative refraction was influenced by preoperative mean anterior corneal curvature, CCT, refraction, and residual stromal thickness.

Keywords: contributing factors; information gain; multicenter; myopia; small-incision lenticule extraction.