Purpose

To evaluate changes in lamina cribrosa (LC) shape, curvature, and depth after trabeculectomy.

Design

Prospective, observational case series.

Participants

A total of 112 patients (118 eyes) with open- or closed-angle glaucoma undergoing trabeculectomy.

Methods

The optic nerve head was imaged using enhanced depth imaging spectral-domain OCT before trabeculectomy and at 6 follow-up visits throughout the first postoperative year. The anterior LC surface and Bruch’s membrane opening were marked in the serial horizontal B scans for the analysis of LC parameters using Morphology 1.0 software. Postoperative morphologic LC changes were assessed.

Main Outcome Measures

The postoperative LC global shape index (GSI), nasal-temporal (N-T) and superior-inferior (S-I) curvatures, and mean and sectoral LC depth (LCD).

Results

The mean LC GSI increased only during the early postoperative period (P = 0.02), resulting in a change toward the saddle-rut shape. There was a flattening of the LC curvature in N-T (P < 0.001) and S-I (P = 0.003) meridians 12 months after trabeculectomy. A shallowing of the mean and sectoral LCD from baseline was significant throughout the entire follow-up period (P < 0.001) and progressed up to postoperative month 6. Twenty-eight patients showed a deepening of the LC from baseline in at least 1 visit. Eyes with shallower LCD compared with baseline responded to intraocular pressure (IOP) reduction with greater movement anteriorly than eyes with deeper LCD (P = 0.002). Greater IOP reduction (P = 0.007), less retinal nerve fiber layer thinning over the year (P = 0.003), and more superiorly-inferiorly curved baseline LC (P = 0.001) were associated with an increase in GSI. Younger age and IOP reduction were related to LC shallowing (P < 0.001, P = 0.002) and N-T flattening (P < 0.001).

Conclusions

In most eyes, trabeculectomy resulted in long-term flattening and shallowing of the LC. However, in some eyes, LC deepened from baseline. Change in LC global shape appeared to be temporal. Reduction in IOP plays an important role in the early phase of LC change; however, in the later phase, LC remodeling may play a crucial role in view of stable IOP.

中文翻译：

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小梁切除术后板状薄板的长期形状，曲率和深度变化

目的

评估小梁切除术后椎板（LC）的形状，曲率和深度的变化。

设计

前瞻性观察病例系列。

参加者

共有112例（118眼）开角型或闭角型青光眼患者接受了小梁切除术。

方法

在小梁切除术之前以及术后第一年的6次随访中，使用增强深度成像光谱域OCT对视神经乳头成像。在连续水平B扫描中标记前LC表面和Bruch膜开口，以使用Morphology 1.0软件分析LC参数。评估术后形态学LC变化。

主要观察指标

术后LC整体形状指数（GSI），鼻颞（NT）和上下（SI）曲率，以及平均和扇形LC深度（LCD）。

结果

平均LC GSI仅在术后早期才增加（P  = 0.02），从而导致鞍形转向。 小梁切除术后12个月，NT（P <0.001）和SI（P = 0.003）经络的LC曲率变平。在整个随访期间，平均LCD和扇形LCD均较基线显着变浅（P <0.001），并一直持续到术后第6个月。28位患者在至少1次访视中显示LC较基线加深。与基线相比，LCD较浅的眼睛对眼内压（IOP）降低的反应比LCD较深的眼睛具有更大的向前移动（P  = 0.002）。更大的IOP降低（P = 0.007），一年中较少的视网膜神经纤维层变薄（P  = 0.003），以及弯曲曲线基线LC的上下偏上（P  = 0.001）与GSI的增加有关。年轻年龄和眼压降低与LC变浅（P <0.001，P  = 0.002）和NT变平坦（P <0.001）有关。

结论

在大多数眼睛中，小梁切除术会导致LC长期变平和变浅。但是，在某些人眼中，LC从基线开始加深。LC整体形状的变化似乎是暂时的。降低眼压在LC改变的早期阶段起着重要的作用。但是，在后期，考虑到稳定的IOP，LC重塑可能起着至关重要的作用。