Are There Filtering Blebs After Canaloplasty?

Purpose: Aim of the study was to assess the development of filtering blebs after canaloplasty. Methods: Twenty eyes of 20 consecutive patients receiving canaloplasty were included. All eyes were examined clinically (slit lamp), and by anterior segment optical coherence tomography and high-frequency ultrasound biomicroscopy to detect filtering blebs. Preoperative and postoperative intraocular pressure (IOP) and medications were recorded. No antimetabolites were used at any time. Two success criteria were defined to assess a possible correlation of bleb formation and success: (1) IOP <= 21mm Hg and minimum 20% IOP reduction without medication and (2) IOP < 18mm Hg without medication. Results: No filtering blebs were detected clinically. One patient had a filtering bleb-like structure as detected by anterior segment optical coherence tomography and ultrasound biomicroscopy. Mean IOP decreased significantly from 22.15 +/- 9.5 mm Hg pre-operatively to 13.3 +/- 9.9mm Hg at last follow-up (at 245 +/- 120.0 d). The number of medications was reduced significantly from 3.15 +/- 1.2 preoperatively to 0.55 +/- 0.94 postoperatively. Complete success rate was 65% for both success criteria. Conclusions: Filtering blebs occur rarely after canaloplasty. In canaloplasty, IOP reduction seems to be independent of subconjunctival aqueous drainage, thus, avoiding the problems of conjunctival scarring.