Elsevier

Ophthalmology

Volume 116, Issue 5, May 2009, Pages 848-855
Ophthalmology

Original article
Evaluation of Trabeculectomy Blebs Using 3-Dimensional Cornea and Anterior Segment Optical Coherence Tomography

https://doi.org/10.1016/j.ophtha.2008.11.019Get rights and content

Objective

To investigate the internal structures of trabeculectomy blebs using 3-dimensional cornea and anterior segment optical coherence tomography (3-D CAS OCT).

Design

Observational case series.

Participants

Thirty-eight filtering blebs in 31 patients who had undergone trabeculectomy examined retrospectively.

Methods

Intrableb structures were examined using 3-D CAS OCT. The blebs were classified clinically as successful (intraocular pressure [IOP] <18 mmHg without glaucoma medication) or failed.

Main Outcome Measures

Bleb structures were assessed in terms of the visibility of the drainage route, scleral flap, and microcysts. The length and height of the internal fluid-filled cavity, maximum and minimum bleb wall thickness, total bleb height, volumes of the internal fluid-filled cavity and hyporeflective area, and number of microcysts were analyzed.

Results

Intrableb drainage route, scleral flap, and microcysts were observed in 92.1%, 94.7%, and 86.8% eyes, respectively. The IOP showed a significant negative correlation with horizontal and vertical length of the fluid-filled cavity (Spearman correlation coefficient [rs] = –0.634; P<0.0001; and rs = –0.539; P = 0.0008, respectively), height of the fluid-filled cavity (rs = –0.334; P = 0.031), maximum bleb wall thickness (rs = –0.491; P = 0.0023), total bleb height (rs = –0.629; P<0.0001), volume of the internal fluid-filled cavity (rs = –0.480; P = 0.0029), volume of hyporeflective area (rs = –0.443; P = 0.0056), and number of microcysts (rs = –0.451; P = 0.0045). There were 26 successful (64.8%) and 12 failed (31.6%) blebs. Significant differences were observed between these groups in IOP (P<0.0001), horizontal and vertical length of the fluid-filled cavity (P<0.0001 and P = 0.0019, respectively), height of the fluid-filled cavity (P = 0.0046), maximum bleb wall thickness (P = 0.0029), total bleb height (P = 0.0003), volume of the internal fluid-filled cavity (P = 0.0006), volume of hyporeflective area (P = 0.0020), and number of microcysts (P = 0.0025).

Conclusions

The internal aqueous humor outflow channel and scleral flap could be visualized, and the 3-D volume of the intrableb cavity was calculated using 3-D CAS OCT. The successful blebs exhibited a large internal fluid-filled cavity, an extensive hyporeflective area, and thicker bleb walls with more microcysts.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Patients and Methods

We retrospectively examined 38 filtering blebs in 31 patients who had undergone trabeculectomy. They were recruited from the consecutive cases seen at the glaucoma clinic of Tsukuba University Hospital. All the patients were of Asian origin with a heavily pigmented iris. The patients comprised 25 males and 6 females in the age range of 20 to 79 years (mean±standard deviation, 57.8±13.9 years). There were 9 eyes with primary open-angle glaucoma, 3 eyes with primary angle-closure glaucoma, 12

Results

Representative photographs and 3-D CAS OCT images of the successful and failed blebs are shown in Figure 2, Figure 3. The microcysts, internal fluid-filled cavity, hyporeflective area, and scleral flap are delineated clearly. The well-functioning blebs exhibited a relatively thick wall, a large internal fluid-filled cavity, and many microcysts. In contrast, the nonfunctioning blebs exhibited a thin wall, a small or no internal fluid-filled cavity, and no microcysts. As shown in Figure 4, the

Discussion

In the present study, the internal morphologic features of filtering blebs were examined by using 3-D CAS OCT. As shown in Figure 1, Figure 2, Figure 3, the microcysts, internal fluid-filled cavity, and scleral flap were visualized clearly by 3-D CAS OCT. The scleral flap and aqueous humor drainage route in the bleb could be detected in more than 90% of the cases. In the successful bleb groups particularly, the scleral flap and aqueous drainage route in the bleb were detected in all eyes. These

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Manuscript no. 2008-651.

Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Supported in part by the Japan Society for the Promotion of Science (Grant-in-Aid for Scientific Research no.: 19791256), Tokyo, Japan.

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