Prospective observation of filtration blebs in high-risk eyes with limbal-based conjunctival flap

To evaluate time-dependent changes in filtering bleb parameters using 3-dimensional anterior segment optical coherence tomography (3-D AS-OCT) in high-risk eyes after a limbal-based trabeculectomy procedure.

Prospective, observational study.

Twenty-three patients who underwent uncombined limbal-based trabeculectomy surgery and who also had a history of prior intraocular surgery.

Of 23 eyes, 15 eyes were followed for 1 year without additional glaucoma surgeries, and their bleb parameters were measured 0.5, 3, 6, and 12 months after the trabeculectomy using 3-dimensional anterior segment optical coherence tomography. The correlations of these parameters to other clinical data were investigated.

Statistical analysis showed significant changes in the bleb wall thickness (0.7 ± 0.4 mm vs 0.4 ± 0.2 mm; p = 0.007) and fluid cavity height (0.3 ± 0.2 mm vs 0.7 ± 0.4 mm; p = 0.005) between 0.5 and 3 months only. The width of the filtration openings at 0.5 months after trabeculectomy (2.1 ± 1.0 mm) was significantly associated with the intraocular pressure at 12 months (15.1 ± 5.7 mm Hg; R² = 0.37, t = -2.65, and p = 0.021).

The width of the filtration opening in the early stage may be a prognostic factor for long-term intraocular pressure control.