Effectiveness and the nomogram of small incision lenticule extraction in the correction of myopic anisometropia in adults
Authors:   Chongqing Medical University, Chongqing 400000, China, Zhang Tong , Zuo Hang-Jia ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Chen Zhi-Jun ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Ji Yan ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Yang Xin ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Lu Xiao-Rong ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Wu Qiong ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Wang Qing ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Xia Jiu-Yi ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Li Meng ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Zhou Chun-Jiang ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Wang Yao ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Hu Ke ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China, Wan Wen-Juan ,   Chongqing Medical University, Chongqing 400000, China; The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing Branch (Municipality Division) of National Clinical Research Center for Ocular Diseases, Chongqing 400000, China
Published: October 2023

AIM: To evaluate the safety, effectiveness, and predictability of small incision lenticule extraction (SMILE) for the treatment of anisometropia, and to explore the personalized design scheme of SMILE in correcting adult myopia anisometropia based on the nomogram.
METHODS: It’s a prospective cohort study. Patients with anisometropic myopia of refractive difference ≥ 2.0 diopters (D) who underwent SMILE between September 2020 and March 2021 were enrolled. Clinical features and visual function were assessed preoperatively and at 1wk, 1, 3, and 6mo after the operation. The examination included tests for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive errors, effectiveness index (preoperative CDVA/postoperative UDVA), safety index (postoperative CDVA/preoperative CDVA), nomogram and stereoscopic function. Paired t-test, Wilcoxon signed-rank test and repeated-measures analyses of variance were used for continuous variables, and Pearson Chi-squared test was used for categorical variables.
RESULTS: The study involved 45 consecutive patients (average age: 25.0±6.9y; 82 out of 90 eyes underwent SMILE, while 8 eyes were not operated). The average preoperative spherical equivalent (SE) was -4.74±0.22 D. Six months after surgery, the effectiveness index was 1.05±0.12, and the safety index was 1.09±0.11. Seventy eyes (85.4%) exhibited SE correction error within ±0.5 D. The percentage of eyes with Titmus stereoscopic function equal to or less than 200” significantly increased from 55.6% preoperatively to 88.9% postoperatively (P<0.05). There was statistically significant difference between higher myopia eyes and contralateral eyes in average nomogram value/spherical refraction ratio.
CONCLUSION: SMILE is safe, effective and predictable in correcting myopic anisometropia, and it improves stereoscopic visual function of anisometropia patients. The precise and individualized design of the nomogram is a vital element to ensure the balance of both eyes after SMILE.