Early Intrableb Features on Anterior Segment Swept-Source Optical Coherence Tomography Predict Surgical Success After Trabeculectomy in Uveitic and Neovascular Glaucoma

Abstract

Background: This study aimed to evaluate prognostic factors of early filtering blebs using anterior segment swept-source optical coherence tomography (AS SS-OCT) in patients with uveitic and neovascular glaucoma. Methods: This retrospective cohort study included 22 eyes from 22 patients who underwent trabeculectomy (11 eyes each with uveitic or neovascular glaucoma). Intrableb characteristics were assessed using AS SS-OCT at 1 month, postoperatively. Surgical success was defined as intraocular pressure (IOP) ≤ 18 mmHg and ≥30% IOP reduction without medication at 12 months. Logistic regression was used to identify the prognostic factors associated with IOP control. Results: Sixteen eyes (72.7%) achieved surgical success, while six (27.3%) were unsuccessful. Eyes with successful IOP control at 12 months showed thicker and less reflective bleb walls with microcysts compared with unsuccessful cases of IOP control, in the early postoperative phase (all p < 0.033). However, IOP at the time of OCT did not significantly differ between the groups (p = 0.083). Multivariate logistic regression analysis revealed that higher bleb wall reflectivity at 1-month post-trabeculectomy was significantly associated with a higher surgical failure rate at 12 months after trabeculectomy (hazard ratio = 1.072, p = 0.032). Conclusions: Early intrableb assessment using AS SS-OCT may be beneficial for managing filtering blebs after trabeculectomy in uveitic and neovascular glaucoma. Higher bleb wall reflectivity in the early post-trabeculectomy phase may indicate poor features of the filtering bleb, suggesting the need for timely interventions for refractory cases.

Keywords: anterior segment swept-source optical coherence tomography; early filtering bleb; neovascular glaucoma; uveitic glaucoma.

Figure 1

Anterior segment swept-source optical coherence tomography image for measuring intrableb parameters. The white and white dotted line indicate the fluid-filled space height and bleb wall thickness, respectively. The white two-way arrow represents the hyporeflective layers with striping phenomenon. The star denotes the fluid-filled space, while the asterisk indicates the scleral flap. The white arrowhead points to the microcyst.

Figure 2

Flow diagram demonstrating patient selection in each group.

Figure 3

Representative AS-OCT images of filtering blebs at 1-month post-trabeculectomy in eyes with different surgical outcomes at 1 year. Images in the left column represent the successful group, while those in the right column represent the unsuccessful group. All blebs appeared clinically diffuse, without signs of encapsulation on slit-lamp examination. (a) A 61-year-old man with uveitic glaucoma (UG) in the left eye showed an intraocular pressure (IOP) of 10 mmHg. The bleb exhibited a prominent striping layer, diffuse microcyst formation, and low bleb wall reflectivity. (b) A 63-year-old man with UG in the right eye had an IOP of 14 mmHg. The bleb showed a larger fluid-filled space but less striping, limited anterior microcysts, and higher reflectivity. (c) A 56-year-old man with neovascular glaucoma (NVG) in the left eye achieved an IOP of 8 mmHg with a bleb showing limited fluid-filled space, diffuse microcyst formation, and low reflectivity. (d) A 50-year-old woman with NVG in the left eye had an IOP of 10 mmHg. Despite a similar fluid-filled space to (c), the bleb demonstrated higher reflectivity, absence of striping, and minimal microcyst formation.