Evaluation of filtering blebs exhibiting transconjunctival oozing using anterior segment optical coherence tomography

To explore the features of filtering blebs exhibiting transconjunctival oozing via three-dimensional anterior segment optical coherence tomography (3D AS-OCT). In this cross-sectional study, 131 eyes of 131 patients exhibiting filtering blebs were examined. Of those, 20 eyes were excluded as flat-shaped, non-functioning bleb. Transconjunctival oozing was defined as transconjunctival aqueous egress evident on the bleb surface, in the absence of any point leak observable using a slit-lamp, as confirmed by application of digital pressure. Total bleb height, the height of the fluid-filled cavity, and bleb wall thickness and density were measured using 3D AS-OCT. Patient age, the etiology of glaucoma, postoperative follow-up period, number of glaucoma medication classes prescribed, intraocular pressure (IOP), grade of bleb vascularity, and bleb parameters were compared in eyes with and without bleb oozing. Sixty (54.0 %) of 111 eyes excluding non-functioning flat blebs exhibited oozing; mean IOP value (11.7 +/- 4.5 vs. 14.8 +/- 4.0 mmHg) and bleb vascularity grade (1.5 +/- 0.7 vs. 2.4 +/- 1.0) were lower than those of eyes without oozing. Total bleb height (1.1 +/- 0.4 vs. 0.9 +/- 0.4 mm), bleb wall thickness (0.7 +/- 0.4 vs. 0.5 +/- 0.3 mm), and bleb wall density (131.3 +/- 45.7 vs. 180.9 +/- 39.8 optical density units) differed significantly between the two groups (oozing vs. non-oozing). Transconjunctival oozing after trabeculectomy with MMC was associated with a low IOP, low-level bleb vascularity, an elevated total bleb height, a thicker bleb wall, and low bleb wall density.