Junjie Wang1,2, Bernardo T Lopes3, Hechen Li1, Riccardo Vinciguerra4, Si Cao1, Songan Wu1, Rong Zhu1, Qinmei Wang1,2, Xiaobo Zheng5,6, Fangjun Bao7,8, Ahmed Elsheikh3,9,10. 1. Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China. 2. The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China. 3. School of Engineering, University of Liverpool, Liverpool, L69 3GH, UK. 4. Humanitas San Pio X Hospital, Milan, Italy. 5. Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China. xbjay911@126.com. 6. The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China. xbjay911@126.com. 7. Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China. bfjmd@126.com. 8. The Institution of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, 325027, Zhejiang, China. bfjmd@126.com. 9. National Institute for Health Research (NIHR) Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK. 10. Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China.
Abstract
BACKGROUND: Corneal refractive surgery has become reliable for correcting refractive errors, but it can induce unintended ocular changes that alter refractive outcomes. This study is to evaluate the unintended changes in ocular biometric parameters over a 6-month follow-up period after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE). METHODS: 156 consecutive myopic patients scheduled for FS-LASIK and SMILE were included in this study. Central corneal thickness (CCT), mean curvature of the corneal posterior surface (Kpm), internal anterior chamber depth (IACD) and the length from corneal endothelium to retina (ER) were evaluated before and after surgery over a 6-month period. RESULTS: Both the FS-LASIK and SMILE groups (closely matched at the pre-surgery stage) experienced flatter Kpm, shallower IACD and decreased ER 1 week post-surgery (P < 0.01), and these changes were larger in FS-LASIK than in SMILE group. During the 1 week to 6 months follow up period, Kpm, IACD and ER remained stable unlike CCT which increased significantly (P < 0.05), more in the FS-LASIK group. CONCLUSIONS: During the follow up, the posterior corneal surface became flatter and shifted posteriorly, the anterior chamber depth and the length from the corneal endothelium to retina decreased significantly compared with the pre-surgery stage. These unintended changes in ocular biometric parameters were greater in patients undergoing FS-LASIK than SMILE. The changes present clear challenges for IOL power calculations and should be considered to avoid affecting the outcome of cataract surgery.
BACKGROUND: Corneal refractive surgery has become reliable for correcting refractive errors, but it can induce unintended ocular changes that alter refractive outcomes. This study is to evaluate the unintended changes in ocular biometric parameters over a 6-month follow-up period after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE). METHODS: 156 consecutive myopicpatients scheduled for FS-LASIK and SMILE were included in this study. Central corneal thickness (CCT), mean curvature of the corneal posterior surface (Kpm), internal anterior chamber depth (IACD) and the length from corneal endothelium to retina (ER) were evaluated before and after surgery over a 6-month period. RESULTS: Both the FS-LASIK and SMILE groups (closely matched at the pre-surgery stage) experienced flatter Kpm, shallower IACD and decreased ER 1 week post-surgery (P < 0.01), and these changes were larger in FS-LASIK than in SMILE group. During the 1 week to 6 months follow up period, Kpm, IACD and ER remained stable unlike CCT which increased significantly (P < 0.05), more in the FS-LASIK group. CONCLUSIONS: During the follow up, the posterior corneal surface became flatter and shifted posteriorly, the anterior chamber depth and the length from the corneal endothelium to retina decreased significantly compared with the pre-surgery stage. These unintended changes in ocular biometric parameters were greater in patients undergoing FS-LASIK than SMILE. The changes present clear challenges for IOL power calculations and should be considered to avoid affecting the outcome of cataract surgery.
Entities:
Keywords:
FS-LASIK; Internal anterior chamber depth; Posterior corneal surface; SMILE; The length from corneal endothelium to retina