Optical coherence tomography analysis of anterior segment parameters before and after laser peripheral iridotomy in primary angle-closure suspects by using CASIA2.

Laser peripheral iridotomy (LPI) is effective in primary angle-closure suspects (PACS); however, predictors for anterior segment alterations after LPI are limited. We aimed to evaluate the anterior segment biometric parameters before and after LPI in PACS using the recently developed, CASIA 2 device of anterior segment optical coherence tomography (AS-OCT). We performed LPI in 52 PACS. Anterior segment parameters, including anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber volume (ACV), iris curvature (ICURVE), iridotrabecular contact (ITC), lens vault (LV), lens thickness (LT), radius of the lens, angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and trabecular iris angle (TIA) at different distances (i.e., 500 μm from the sclera spur), were evaluated before and after LPI using CASIA 2. Eyes of PACS after LPI had a greater ACV, AOD, ARA, TISA, and TIA, and a lower ITC and ICURVE (all p < 0.001) than those before LPI. On a 360° scan, the anterior chamber angle in the superior quadrant increased the most after the LPI. A higher baseline LT was significantly associated with a greater postoperative increase in AOD 500, ARA 500, TISA 500, and TIA 500 (p = 0.001, p = 0.010, p = 0.004, and p < 0.001, respectively). We found that LPI widens the anterior chamber angle in the PACS, especially, in the superior quadrant around the iridotomy hole. Eyes with a thicker lens are more likely to experience angle opening because of the LPI.

激光周边虹膜切开术（LPI）对原发性闭角型青光眼疑似患者（PACS）有效；然而，LPI术后眼前节改变的预测因素有限。我们旨在使用新近研发的眼前节光学相干断层扫描仪（AS - OCT）的CASIA 2设备评估PACS患者LPI前后的眼前节生物测量参数。 我们对52例PACS患者进行了LPI。使用CASIA 2在LPI前后评估眼前节参数，包括前房深度（ACD）、前房宽度（ACW）、前房容积（ACV）、虹膜曲率（ICURVE）、虹膜小梁接触（ITC）、晶状体拱高（LV）、晶状体厚度（LT）、晶状体半径、房角开放距离（AOD）、房角隐窝面积（ARA）、小梁虹膜间隙面积（TISA）以及不同距离（即距巩膜突500μm）的小梁虹膜角（TIA）。 PACS患者LPI术后的眼睛与术前相比，ACV、AOD、ARA、TISA和TIA更大，ITC和ICURVE更低（所有P < 0.001）。在360°扫描中，LPI术后上方象限的前房角增加最多。较高的基线LT与术后AOD500、ARA500、TISA500和TIA500的更大增加显著相关（分别为P = 0.001、P = 0.010、P = 0.004和P < 0.001）。 我们发现LPI使PACS患者的前房角增宽，尤其是在虹膜切开孔周围的上方象限。晶状体较厚的眼睛更有可能因LPI而出现房角开放。