Evaluation of trabeculectomy blebs using 3-dimensional cornea and anterior segment optical coherence tomography

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

Observational case series.

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

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.

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.

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 [r(s)] = -0.634; P<0.0001; and r(s) = -0.539; P = 0.0008, respectively), height of the fluid-filled cavity (r(s) = -0.334; P = 0.031), maximum bleb wall thickness (r(s) = -0.491; P = 0.0023), total bleb height (r(s) = -0.629; P<0.0001), volume of the internal fluid-filled cavity (r(s) = -0.480; P = 0.0029), volume of hyporeflective area (r(s) = -0.443; P = 0.0056), and number of microcysts (r(s) = -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).

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.

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