Affiliation:
1. Hainan Eye Hospital and Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Centre, Sun Yat-sen University, Guangzhou, China
2. Yichang Maternal and Child Health Hospital, School of Clinical Medicine for Women and Children, China Three Gorges University, Hubei, China
3. The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China
4. Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-Sen University, Guangzhou, China
Abstract
Purpose To evaluate the corneal biological parameters stability between the different corneal residual bed thickness (RBT) after Small Incision Lenticule Extraction (SMILE). Methods In this prospective clinical trial, 127 eyes of 64 patients underwent SMILE. According to the corneal RBT, the patients were divided into the 250–270 µm, 270–290 µm and 290–310 µm groups. Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) and Scheimpflug camera (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany) measurements were performed preoperatively, 1 day, 1week, 1month and 3 months after surgery. Results The keratometer values among the three groups were no significant differences in postoperative periods (each P > 0.05), except the corneal thickness values (each P < 0.05). In the 250–270 µm and 270–290 µm groups, the keratometer and corneal thickness values were decreased at postoperative 1 week and increased at 1 and 3 months. The 290–310 µm group significantly higher posterior maximum elevation (PME) than the 250–270 µm group at 1 and 3 months (P = 0.022, 0.022, respectively), and higher preoperative thinnest point (PTE) at 1 week and 1 month (P = 0.013, 0.035, respectively). The PME of the 290–310 µm group was higher than the 270–290 µm group at 3 months (P = 0.045), and higher PTE at 1 week and 3 months (P = 0.022, 0.02, respectively). In all three groups, the maximal deformation amplitude (DA) was significantly higher at 1 and 3 months compared to postoperative 1 day and 1 week, and the IOP was decreased at 1 month then recovered at 3 months (each P < 0.05).The DA of the 250–270 µm group was significantly higher than the 290–310 µm group at postoperative 1 week, 1 and 3 months (P = 0.001, 0.01, 0.02, respectively). The change of the posterior corneal elevation and biomechanical parameters values were no significant differences among the three groups in postoperative periods (each P > 0.05). Conclusions The range of 250–310 µm RBT was safe and stable at the early postoperative of SMILE. The RBT may be positively correlated with the posterior corneal elevation.
Funder
the Hainan Province Clinical Medical Center
National Natural Science Foundation of China
Hainan Natural Science Foundation Youth Fund Project
Science and Technology Planning Project of Hainan Province
Subject
Ophthalmology,General Medicine