Purpose

To identify the presence or absence of 3 identifiable landmarks: trabecular meshwork (TM), Schlemm's canal (SC), and a novel landmark termed the band of extracanalicular limbal lamina (BELL), which is a landmark adjacent to SC visible on anterior segment (AS) OCT. These landmarks also were analyzed pathologically to identify all 3 landmarks.

Design

Retrospective review.

Participants

One eye per participant from prior institutional review board-approved studies in which AS OCT imaging was performed.

Methods

Horizontal images from 2-dimensional angle analysis scans using a CASIA SS-1000 (Tomey, Nagoya, Japan) AS OCT were evaluated by masked readers. Logistic regression was used to analyze the potential factors of age, gender, race, intraocular pressure, gonioscopy grade, angle location, and history or presence of surgery on the visibility of these structures. Pathologic correlation on 5 previously enucleated eyes also was performed.

Main Outcome Measures

Presence or absence of angle landmarks—TM, SC, and BELL—using Anterior Chamber Analysis and Interpretation software (ACAI, Houston, TX).

Results

Three hundred three angles of 153 horizontal images were included in this study. The mean age was 51.5±16.0 years, with 98 women (64%) and 100 white persons (66%). The outer border of the BELL was observed in 288 angles (95%), TM was found in 220 angles (73%), and SC was seen in 120 angles (40%). The outer border of the BELL was more visible in white persons (P = 0.02) than Asians and in eyes with a Spaeth gonioscopy grade of E than those with a grade of A (P = 0.02). Both TM (P = 0.001) and SC (P = 0.001) were more visible in temporal angles (81% for TM, 49% for SC) than in nasal angles (64% for TM, 30% for SC). Additionally, SC was more visible in open angles (43%) than in narrow angles (27%; P = 0.02). These 3 structures were verified in a pathologic study.

Conclusions

We identified a novel AS OCT landmark adjacent to SC. This structure also was identified on pathologic samples from enucleated eyes. Further study is needed to determine the pathophysiologic relevance of these findings.

中文翻译：

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表征小梁网复合体的前节OCT角度地标

目的

为了确定是否存在3个可识别的界标：小梁网（TM），Schlemm根管（SC）和一种新颖的界标，称为前小管旁角膜缘带（BELL），这是前节可见的与SC相邻的界标（ AS）OCT。还对这些地标进行了病理分析，以识别所有3个地标。

设计

回顾性审查。

参加者

每位参与者均获得先前经过机构审查委员会批准的研究（其中进行了AS OCT成像）的一只眼睛。

方法

使用带遮罩的阅读器评估了使用CASIA SS-1000（日本名古屋市通美市）的二维角度分析扫描获得的水平图像。使用Logistic回归分析这些结构的可见性，年龄，性别，种族，眼压，角膜镜检查等级，角度位置以及手术史或是否存在手术的潜在因素。还对5只先前摘除眼睛的眼睛进行了病理学相关性分析。

主要观察指标

使用前房分析和解释软件（ACAI，德克萨斯州休斯敦），是否存在角度界标（TM，SC和BELL）。

结果

这项研究包括153个水平图像的303个角度。平均年龄为51.5±16.0岁，其中98位女性（64％）和100位白人（66％）。在288个角度（95％）观察到BELL的外边界，在220个角度（73％）观察到TM，在120个角度（40％）观察到SC。BELL的外缘在白人（P  = 0.02）中比在亚洲人中更明显，在Spaeth角膜镜检查等级为E的眼中比在A级（P  = 0.02）的人更明显。 在颞角（TM为81％，SC为49％ ）中，TM（P = 0.001）和SC（P = 0.001）都比鼻角（TM为64％，SC为30％）更明显。此外，SC在开角（43％）处比在窄角（27％; P = 0.02）。这三个结构在病理研究中得到了验证。

结论

我们确定了与SC相邻的新型AS OCT地标。在摘除眼睛的病理样本上也鉴定出了这种结构。需要进一步研究以确定这些发现的病理生理相关性。