Anterior Segment Optical Coherence Tomography (As-Oct) Imaging Of Conjunctival Filtering Blebs After Trabeculectomy Surgery

To evaluate conjunctival filtering bleb morphology in patients that underwent trabeculectomy/phaco-trabeculectomy in the previous 6-12 months using AS-OCT.

Retrospective observational study at Instituto de Oftalmologia Dr. Gama Pinto, Lisbon, Portugal. 

Study protocol included 15 eyes (from 10 patients) with primary open-angle glaucoma subjected to trabeculectomy/phaco-trabeculectomy, using mytomicin C or Ologen, that underwent AS-OCT imaging of the filtering bleb in 6-12 months postop. Image acquisition included the underlying scleral flap. AS-OCT (using SD-OCT Spectralis) evaluation included: scleral opening, bleb cavity (and its maximum height), bleb wall reflectivity and subepithelial cysts. Patient clinical data included: gender, age, preoperative and 6-12 months post IOP, topical/oral ocular hypotensive medication, laser suturolysis, immeditate postoperative complications (such as ocular hypo/hypertension in the first month).

Mean IOP was 12.2 mmHg (+/- 5.3 mmHg) with median number of glaucoma medication of 1. Patients with clinically functional bleb and low IOP without glaucoma medication tended to have thicker bleb cavities, recognizable scleral opening and lower bleb wall reflectivity.

AS-OCT is a promising imaging tool for filtering blebs after trabeculectomy surgery, as it may help clinicians in distinguishing between functioning and nonfunctioning blebs by describing bleb-wall features, bleb cavity, and scleral opening.