Evaluation of Successful and Failed Filtering Blebs after Trabeculectomy Using Anterior Segment Optical Coherence Tomography

Purpose: To evaluate filtering bleb characteristics using anterior segment optical coherence tomography (AS‑OCT) and analyze correlations between these parameters and intraocular pressure (IOP). Methods: The study included 54 eyes of 43 patients who underwent trabeculectomy with mitomycin‑C. The patients were divided into two groups based on mean postoperative IOP. The criterion for surgical success was mean unmedicated postoperative IOP ≤18 mmHg. Patients with IOP values >18 mmHg were prescribed anti‑glaucoma drops and classified as a surgical failure. All patients underwent AS‑OCT, and maximum bleb height, maximum bleb wall thickness, and maximum fluid‑filled cavity height were measured. AS‑OCT bleb parameters were compared between the successful and failed groups. Results: Of the 54 eyes, 37 (68.5%) were in the successful group, and 17 (31.5%) were in the failed group. Mean preoperative IOP values in the successful and failed groups were 26.9 ± 6.5 mmHg and 22.9 ± 4.9 mmHg, preoperatively, versus postoperative values of 13.3 ± 2.1 mmHg and 22.8 ± 2.8 mmHg, respectively. Mean postoperative follow‑up time was 17.4 ± 9.5 months in the successful group and 19.1 ± 10.1 months in the failed group (P = 0.22). In the successful and failed groups, mean bleb height was 1473.7 ± 150.6 μm and 1165.4 ± 217 μm (P < 0.001), bleb wall thickness was 670.5 ± 119.9 μm and 538.8 ± 144.3 μm (P = 0.001), and fluid‑filled cavity height was 736.5 ± 196.8 μm versus 532.5 ± 226.2 μm (P = 0.001), respectively. Conclusions: The results of this study showed that higher AS‑OCT values for bleb height, wall thickness, and fluid‑filled cavity height were associated with greater functional success. These parameters may be helpful in determining bleb functionality.