Clinical evaluation of aqueous outflow system in vivo and correlation with intraocular pressure before and after non-penetrating glaucoma surgery.

Abstract

The aim of this study was to evaluate the aqueous outflow system through channelography with fluorescein during non-penetrating glaucoma surgery (canaloplasty or phacocanaloplasty) and find correlations with preoperative and postoperative intraocular pressure (IOP). Thirty-six patients (40 eyes) who had channelography while undergoing non-penetrating glaucoma surgery were included in this prospective study. Several parameters assessed during the channelography included: diffuse and superficial scleral staining, the number of visible superficial connections to collectors, trabecular permeability and number of micro-ruptures of the trabecular meshwork. IOP, the best-corrected visual acuity, the number of glaucoma medications was recorded at 1day, 7days, 3months and 6months after the operation. The change in IOP at 6months from baseline significantly correlated with the number of visible superficial connections to collectors (r=0.4, p=0.021). Eyes with canaloplasty showed a mean baseline IOP of 19.4 (4.9)mmHg and mean glaucoma medication usage of 2.9 (1.0), which decreased to 13.2 (3.1)mmHg with 0.3 (0.8) medications, respectively, at 6months postoperatively (p<0.001). Eyes with phacocanaloplasty surgery showed a mean baseline IOP of 28.2 (9.6)mmHg with 2.6 (0.9) mean drugs, which decreased to IOP of 12.8 (3.4)mmHg with 0.5 (0.8) medications at 6months (p<0.001). A larger number of defined visible superficial connections to collectors after injection of fluorescein into SC is related to a more pronounced IOP decrease after non-penetrating glaucoma surgery.