PURPOSE To describe a new intraoperative sign called the "gas bubble escape" (GBE) sign to predict the ease of dissection and immediate postoperative quality of vision after small incision lenticule extraction (SMILE). METHODS The term GBE sign refers to the escape of gas bubbles followed by an immediate clarity of the interface on delineation of the lenticule planes in SMILE. This sign may indicate an optimized laser energy, which may facilitate an easy dissection of lenticule, potentially resulting in good quality of vision immediately postoperatively. This prospective study included 100 eyes of 50 patients undergoing bilateral myopic SMILE, wherein a randomly selected 32 (29 patients) of 68 eyes showing the GBE sign intraoperatively were compared with 32 eyes (20 patients) that did not show this sign. A single surgeon performed all surgeries using the same technique and energy parameters (150 nJ energy, 4.5 µm spot spacing). At postoperative 1 day and 1 month, uncorrected distance visual acuity (UDVA), Objective Scatter Index (OSI) score, and modulation transfer function (MTF) cut-off were compared between the two groups using a double-pass system. RESULTS On day 1, the mean OSI score was significantly lower (0.78 ± 0.32) in the GBE group compared to the no GBE group (1.11 ± 0.90) (P = .03). The mean UDVA was also significantly better in the GBE group (P = .001). MTF cut-off was comparable between both groups. However, at 1 month all of the above parameters were comparable between the two study groups (P > .05). CONCLUSIONS The gas bubble escape sign may be a useful indicator of energy optimization, potentially resulting in good visual outcomes in the immediate postoperative period following SMILE. [J Refract Surg. 2019;35(7):467-472.].

中文翻译：

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气泡逸出征：一种新的术中征兆，可预测小切口小孔摘除后的即时视觉质量。

目的描述一种新的术中体征，称为“气泡逃逸”（GBE）体征，以预测小切口小孔镜摘除术（SMILE）后的解剖简便性和术后立即的视觉质量。方法GBE符号是指气泡的逸出，然后根据SMILE中微透镜平面的轮廓立即清晰地显示界面。该体征可能表明激光能量最佳，这可能有助于轻松摘除微透镜，可能在术后立即产生良好的视觉质量。这项前瞻性研究包括50例接受双侧近视SMILE的患者中的100眼，其中随机选择了术中显示GBE征象的68眼中的32眼（29例）与未显示该征象的32眼（20例）进行了比较。一位外科医生使用相同的技术和能量参数（150 nJ能量，4.5 µm点间距）执行所有手术。术后1天和1个月，使用双通道系统比较两组的未矫正远视力（UDVA），客观散射指数（OSI）得分和调制传递函数（MTF）截止值。结果在第1天，GBE组的平均OSI得分显着低于无GBE组（1.11±0.90）（P = .03）（0.78±0.32）（P = .03）。GBE组的平均UDVA也明显更好（P = .001）。两组之间的MTF截止值是可比较的。然而，两个研究组在1个月时所有上述参数均具有可比性（P> .05）。结论气泡逸出迹象可能是能源优化的有用指标，在SMILE术后不久可能会导致良好的视觉效果。[J Refract Surg。2019; 35（7）：467-472。]。