Aim To assess the epithelial features of the bulbar conjunctiva using in vivo confocal microscopy in patients with glaucoma undergoing canaloplasty.

Methods Thirty consecutive patients with glaucoma were enrolled. Canaloplasty was considered successful if the preoperative intraocular pressure (IOP) was reduced by one-third. The conjunctiva was examined using confocal laser-scanning microscopy 1 week before (baseline) and 12 weeks after surgery. The mean density (MMD, cysts/mm²) and mean area (MMA, μm²) of conjunctival microcysts and IOP were measured. Anterior segment optical coherence tomography was performed to evaluate post-operative trabecular distension and scleral modifications at the surgery site.

Results Twelve weeks after surgery, canaloplasty was successful in 23 patients (group 1) but unsuccessful in 7 (group 2). At baseline, IOP was 28.1±2.98 and 28.3±2.81 mm Hg, MMD was 10.61±4.31 and 11.35±5.6 and MMA was 2845.02±411.85 and 2700.56±518.85 in groups 1 and 2, respectively (p>0.05). Twelve weeks after canaloplasty, mean IOP was 13.2±4.48 (p<0.05) and 24.6±3.48 mm Hg in groups 1 and 2, respectively. In group 1, MMD and MMA were 37.86±21.4 and 11997.84±8630.35, respectively, a fourfold increase compared to baseline (p<0.001); no significant differences were found in group 2. Conjunctival bleb was not documented in any case.

Conclusions Conjunctival microcysts were evident in all glaucomatous eyes prior to surgery, and tended to increase in density and surface area after successful canaloplasty. These findings indicated enhanced aqueous humour filtration across the sclera and conjunctiva after canaloplasty.