PURPOSE To compare theoretical values from the small incision lenticule extraction (SMILE) lenticule thickness readout with change in axial length measurements taken with the IOLMaster. METHODS We prospectively studied 214 eyes from 107 patients undergoing bilateral SMILE surgery for myopia or myopic astigmatism between December 2014 and May 2017 at an ophthalmological practice in Singapore. All eyes were examined pre-operatively and 1 and 3 months post-operatively with the IOLMaster following SMILE surgery. Achieved lenticule thickness was taken as the change in axial length after surgery. A linear mixed-effects model was used to examine changes in axial length, spherical equivalent and acuity over time. The relationships between change in axial length and theoretical lenticule thickness and spherical equivalent were examined with multiple linear regression analyses, and model prediction was assessed with adjusted R2 statistics. RESULTS Mean (95% confidence interval [CI]) spherical equivalent pre-operatively was - 5.25 (95% CI - 5.38 to - 5.12) diopters (D), at 1 month was 0.04 (95% CI - 0.09 to 0.17) D (p < 0.001), and at 3 months was - 0.02 (95% CI - 0.15 to 0.11) D (p < 0.001). Mean (95% CI) pre-operative axial length was 27,726 (95% CI 25,595 to 25,857) μm. Post-operative axial length at 1 month was significantly shorter at 25,595 (95% CI 25,464 to 25,726) μm (p < 0.001) with no change thereafter (p = 0.647). Pre-operative mean ± standard deviation (SD) refractive target was 0.24 (± 0.3) D, and mean difference between target and post-operative spherical equivalent at 1 month was 0.20 D (95% CI 0.16 to 0.25 D, p < 0.001). Multiple regression analysis showed that change in axial length at 1 month was, on average, 5% lower than theoretical lenticule thickness, indicating an average difference of 5.4 μm (95% CI 5.2 to 5.6 μm). Preoperative spherical equivalent predicted negative association with change in axial length at 1 month (β = - 14.8, 95% CI - 18.2 to - 11.3, adjusted R2 = 0.457, p < 0.001). CONCLUSIONS Calculated lenticule thickness values were less than expected, and post-operative refractive outcomes at 1 month showed a slight under-correction. Further research in this area is needed to validate these findings.

中文翻译：

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与使用IOLMaster进行轴向长度测量的变化相比，小切口小孔摘除（SMILE）的小孔厚度读数。

目的将小切口小孔镜摘除（SMILE）的小孔镜厚度读数与IOLMaster进行的轴向长度测量值的变化进行比较，以比较理论值。方法我们在新加坡的眼科诊所前瞻性地研究了2014年12月至2017年5月之间接受双侧SMILE手术的近视或近视散光的107例患者的214眼。SMILE手术后，在术前以及术后1个月和3个月使用IOLMaster检查所有眼睛。手术后获得的小孔厚度作为轴向长度的变化。使用线性混合效应模型来检查轴向长度，球当量和视敏度随时间的变化。通过多次线性回归分析检查了轴长变化与理论小透镜厚度和球面当量之间的关系，并通过调整后的R2统计量评估了模型预测。结果术前平均（95％置信区间[CI]）球形当量为-5.25（95％CI-5.38至-5.12）屈光度（D），1个月时为0.04（95％CI-0.09至0.17）D（ p <0.001），而在3个月时为-0.02（95％CI-0.15至0.11）D（p <0.001）。术前平均轴向长度（95％CI）为27,726（95％CI为25,595至25,857）μm。术后1个月的轴向长度显着缩短为25,595（95％CI 25,464至25,726）μm（p <0.001），此后没有变化（p = 0.647）。术前屈光目标的平均值±标准差（SD）为0.24（±0.3）D，1个月时目标与术后球体当量之间的平均差为0.20 D（95％CI 0.16至0.25 D，p <0.001）。多元回归分析显示，在1个月时，轴向长度的变化平均比理论小透镜厚度小5％，表明平均差异为5.4μm（95％CI 5.2至5.6μm）。术前球形当量与1个月时轴向长度变化呈负相关（β=-14.8，95％CI-18.2至-11.3，调整后R2 = 0.457，p <0.001）。结论计算得出的微透镜厚度值低于预期，术后1个月的屈光结果显示矫正略有不足。需要对该领域进行进一步研究以验证这些发现。多元回归分析显示，在1个月时，轴向长度的变化平均比理论小透镜厚度小5％，表明平均差异为5.4μm（95％CI 5.2至5.6μm）。术前球形当量与1个月时轴向长度变化呈负相关（β=-14.8，95％CI-18.2至-11.3，调整后R2 = 0.457，p <0.001）。结论计算得出的微透镜厚度值低于预期，术后1个月的屈光结果显示矫正略有不足。需要对该领域进行进一步研究以验证这些发现。多元回归分析显示，在1个月时，轴向长度的变化平均比理论小透镜厚度小5％，表明平均差异为5.4μm（95％CI 5.2至5.6μm）。术前球形当量与1个月时轴向长度变化呈负相关（β=-14.8，95％CI-18.2至-11.3，调整后R2 = 0.457，p <0.001）。结论计算得出的微透镜厚度值低于预期，术后1个月的屈光结果显示矫正略有不足。需要对该领域进行进一步研究以验证这些发现。术前球形当量与1个月时轴向长度变化呈负相关（β=-14.8，95％CI-18.2至-11.3，调整后R2 = 0.457，p <0.001）。结论计算得出的微透镜厚度值低于预期，术后1个月的屈光结果显示矫正略有不足。需要对该领域进行进一步研究以验证这些发现。术前球形当量与1个月时轴向长度变化呈负相关（β=-14.8，95％CI-18.2至-11.3，调整后R2 = 0.457，p <0.001）。结论计算得出的微透镜厚度值低于预期，术后1个月的屈光结果显示矫正略有不足。需要对该领域进行进一步研究以验证这些发现。