[Evaluation of visual function and patient satisfaction 5 years after SMILE with micro-monovision in myopic patients...

Objective: To evaluate the changes of binocular visual function and patient satisfaction after small-incision lenticule extraction (SMILE) with micro-monovision in myopic patients with presbyopia. Methods: This was a single-arm clinical trial. Myopic patients with presbyopia who underwent micro-monovision SMILE at Beijing Tongren Hospital, Capital Medical University, from January 2019 to March 2021 were enrolled. The surgical design principle was full correction of the dominant eye for distance vision, with the non-dominant eye undercorrected by -1.50 D to -0.50 D for near vision. Best corrected distance visual acuity and best corrected near visual acuity (CNVA) for the dominant eye, non-dominant eye, and both eyes were measured before surgery. Uncorrected distance and near visual acuity (UDVA, UNVA), CDVA, and CNVA for the dominant eye, non-dominant eye, and both eyes were measured at 1, 3, 6 months, 3 years, and 5 years after surgery. Accommodative function parameters were measured preoperatively and at each postoperative follow-up visit, including binocular accommodative amplitude (AMP) measured by the push-up method, accommodative response (BCC) measured by the binocular cross-cylinder method, negative relative accommodation (NRA), and positive relative accommodation (PRA), as well as distance and near stereopsis and Worth 4-dot tests. A visual satisfaction questionnaire was administered after surgery. Results: A total of 51 patients (102 eyes) with myopia and presbyopia were included, comprising 19 males and 32 females, aged (41.68±2.47) years. Sixteen patients (32 eyes) completed the 5-year follow-up. The binocular UDVA and UNVA were (-0.02±0.06) logMAR and (0.01±0.09) logMAR at 5 years after surgery, respectively. The spherical equivalent of the dominant and non-dominant eyes was (-0.24±0.22) D and (-0.80±0.37) D, respectively. The binocular AMP decreased from (5.66±0.28) D before surgery to (4.36±0.19) D at 1 month after surgery, and returned to the preoperative level at 3 months after surgery; The PRA decreased from (-1.93±0.17) D before surgery to (-1.33±0.13) D at 1 month after surgery, and returned to the preoperative level at 6 months after surgery. The BCC increased at 1 month after surgery and returned to the preoperative level at 6 months after surgery (differences across time points were all statistically significant, P<0.05). These indicators slightly decreased at 3 and 5 years postoperatively compared with their respective recovered levels. There were no statistically significant differences in NRA and near stereopsis at any postoperative follow-up time point compared with preoperative values. All patients achieved 60″ distance and near stereopsis at each postoperative follow-up visit point, and the Worth 4-dot tests showed both central and peripheral fusion function in both eyes. The subjective satisfaction score was (9.06±1.18) (out of 10) at 5 years after surgery, with a satisfaction rate of 15/16. Conclusions: SMILE with micro-monovision had an impact on accommodative function in the early postoperative stage. The AMP, PRA, and BCC returned to preoperative levels at 3 and 6 months postoperatively, with a slight decrease at 3 to 5 years. The procedure did not affect binocular visual functions such as fusion and stereopsis. At 5 years after surgery, patients exhibited good distance and near vision, maintained binocular visual functions, and reported high subjective satisfaction.