Near binocular visual function after SMILE surgery for myopia

Abstract

KEYWORDSNear heterophoria; Near point convergence; Small incision lenticule extraction (SMILE); Visual fatigue 2 Abstract Purpose: To analyze the changes of near binocular vision function after small incision lenticule extraction and association with asthenopia. Methods: This was a retrospective study Twenty-five myopic patients who underwent small incision lenticular extraction (SMILE) surgery from Tianjin Eye Hospital were included in this study The values of parameters of near binocular vision function were measured at preoperative, 1 week, 1 month and 3 months postoperatively including near heterophoria, near point convergence (NPC), horizontal base-in fusional reserves (BIFR) and base-out fusional reserves (BOFR). The patients were grouped by the preoperative symptoms scores. The comparisons among different follow-up periods were conducted by the repeated measures analysis of variance. The Pearson correlation coefficient (r) was used to evaluate the linear fit of the relationship between variables. Multiple linear regressions were used to analyze the relationship between asthenopia and parameters of binocular and accommodative function. Results: The NPC significantly increased at 1 week and 1 month after SMILE and then get back to the level of preoperatively in 3 months postoperatively. Near heterophoria significantly decreased at 1 week after SMILE and then remained stable in 3 months postoperatively. In the regression analysis, there was no significant association between the values of the fatigue questionnaire at different stages after SMILE operation and the parameters of near binocular visual function (P>0.05). However, there was significant positive correlation among each visit with the preoperative visual fatigue questionnaire P<0.05).There was no significant difference in the parameters of binocular visual function between the normal group and the fatigue group. For the visual fatigue group, there was positive correlation between the score of visual fatigue questionnaire 1 week after SMILE surgery and the difference in near horizontal phoria between 1w postoperative and that preoperative (r=0.523, P=0.046), and significant negative correlation with the recovery point of BOFR at 1 week (r=-0.581, P=0.023). Conclusion: SMILE surgery wouldn't influence the binocular vision in the short term. Since there was no significant association between binocular vision function and visual fatigue, factors of asthenopia in the early period of SMILE surgery should be further studied. Background Declarations Ethics approval and consent to participateThis study was approved by the Ethics Committee of Tianjin Eye Hospital and adhered to the tenets of the Declaration of Helsinki. Written informed consent to use any clinical data for analysis and publication was obtained from all patients prior to surgery.