Objective To analyse blebs of phacotrabeculectomies performed with Ologen collagen implants (ProTop & MediKing, Taipei, Taiwan) and to compare these with blebs of mitomycin C (MMC)–augmented phacotrabeculectomies.

Methods 33 participants underwent phacotrabeculectomy with Ologen implants, and 33 controls underwent phacotrabeculectomy with MMC. Blebs were analysed for height and area using anterior segment optical coherence tomography (ASOCT) at 30, 60 and 90 days after surgery and were also graded clinically with the Moorfields bleb grading system (MBGS) 60 days after surgery.

Results With ASOCT, there was no difference in mean bleb height at 30 and 60 days, but at 90 days, bleb height was lower in the Ologen group (Ologen vs MMC, 0.74±0.20 vs 1.00±0.28 mm, p<0.001). There was no difference in mean bleb area at 30, 60 or 90 days. Mean reduction in intraocular pressure at 90 days was greater in the MMC group (Ologen vs MMC, 2.18±4.93 vs 8.00 ±7.60 mm Hg, p<0.001). At 90 days, the Ologen implants were visible in ASOCT images in 13 (39.4%) of 33 participants. With the Moorfields bleb grading system at 60 days, there was no difference in maximal bleb area score between the groups, but bleb height score was lower (Ologen vs MMC, 1.53±0.51 vs 1.81±0.59, p=0.05) and central bleb vascularity score was higher in the Ologen group (3.88±0.55 vs 2.91±0.59, p<0.001).

Conclusions Within 3 months of surgery, mean bleb height was lower in the Ologen blebs compared with the MMC blebs. The Ologen implants had not degraded in a third of eyes.