Stein Eye Institute, University of California, Los Angeles.
Doheny Eye Institute, University of California, Los Angeles.
JAMA Ophthalmol. 2018 Sep 1;136(9):1041-1045. doi: 10.1001/jamaophthalmol.2018.2766.
Anterior segment ischemia (ASI) is a rare but potentially serious complication of strabismus surgery. Indocyanine green angiography and fluorescein angiography have been used to reveal iris-filling defects for clinicians considering a patient's risk of ASI. However, both are limited by invasive and time-consuming nature and potential adverse effects. Recently, optic coherence tomography angiography (OCT-A) has been introduced and used to image iris vasculature in individuals without abnormalities.
To determine the use of iris OCT-A for patients undergoing strabismus surgery and who are at risk for ASI.
DESIGN, SETTING, AND PARTICIPANTS: This prospective case series study took place in an academic center. Adults undergoing strabismus surgery on at least 1 vertical muscle were prospectively recruited. The study took place from June to November 2017, and analysis began in January 2018.
Indocyanine green angiography and OCT-A of the iris preoperatively and 1 day postoperatively.
A masked examiner evaluated all images and determined whether any filling defects were present qualitatively (lack of perfusion) and quantitatively (for OCT-A using internal software to calculate vessel density).
Ten eyes of 9 individuals (mean [SD] age, 63 [11] years) were included. Two individuals (22.2%) identified as Hispanic, and 7 (77.8%) identified as white. There were 6 women (66.7%). The mean preoperative vessel density (percentage of the area occupied by vessels) averaged for all quadrants decreased from 57% preoperatively to 55% postoperatively (mean difference, 2%; 95% CI, 0.4%-4.2%; P = .05). When comparing quadrants adjacent to operated muscles, the mean vessel density decreased from 56% to 53% (mean difference, 2.6%; 95% CI, 0.17%-4.8%; P = .02). In addition, OCT-A detected vascular filling defects in the quadrant adjacent to the operated muscle on the patients in whom they were present (n = 1, inferior rectus recession).
In this preliminary study, OCT-A determined iris vessel filling defects when present. In addition, OCT-A gives qualitative vessel density values that can be compared preoperatively and postoperatively although the clinical relevance of small differences is not known. While only 10 eyes were evaluated, and as such generalizability of these findings cannot be determined, the results suggest that OCT-A may be a useful tool in the evaluation of patients undergoing strabismus surgery to determine whether a patient is at risk to develop ASI.
前段缺血（ASI）是斜视手术的一种罕见但潜在严重的并发症。吲哚菁绿血管造影和荧光素血管造影已被用于显示虹膜充盈缺陷，以便临床医生评估患者发生 ASI 的风险。然而，这两种方法都受到侵袭性和耗时以及潜在的不良反应的限制。最近，光学相干断层扫描血管造影（OCT-A）已经被引入并用于成像无异常个体的虹膜血管。
确定在接受斜视手术且有发生 ASI 风险的患者中使用虹膜 OCT-A。
设计、设置和参与者：这项前瞻性病例系列研究在一个学术中心进行。前瞻性招募了至少接受 1 条垂直肌肉斜视手术的成年人。研究于 2017 年 6 月至 11 月进行，分析于 2018 年 1 月开始。
术前和术后 1 天进行吲哚菁绿血管造影和虹膜 OCT-A。
一名经过盲法训练的检查人员评估所有图像，并定性（灌注不足）和定量（使用内部软件计算血管密度对 OCT-A 进行评估）确定是否存在充盈缺陷。
纳入了 9 名个体的 10 只眼（平均[SD]年龄，63[11]岁）。2 名个体（22.2%）为西班牙裔，7 名（77.8%）为白人。有 6 名女性（66.7%）。所有象限的术前平均血管密度（以血管面积占比表示）从术前的 57%平均下降至术后的 55%（平均差异，2%；95%CI，0.4%-4.2%；P=.05）。当比较毗邻手术肌肉的象限时，血管密度从 56%降至 53%（平均差异，2.6%；95%CI，0.17%-4.8%；P=.02）。此外，OCT-A 在存在血管充盈缺陷的患者（n=1，下直肌后退术）的毗邻手术肌肉象限中检测到血管充盈缺陷。
在这项初步研究中，OCT-A 确定了存在的虹膜血管充盈缺陷。此外，尽管尚不清楚小差异的临床意义，但 OCT-A 可提供可用于术前和术后比较的定性血管密度值。虽然仅评估了 10 只眼，因此无法确定这些发现的普遍性，但结果表明，OCT-A 可能是评估接受斜视手术的患者是否有发生 ASI 风险的有用工具。
