Abstract
Purpose :
To compare the safety and efficacy of an ab-externo (canaloplasty) with an ab-interno (the scaffold) Schlemm's canal dilating surgical procedure
Methods :
The records of patients who underwent between January 2011 and January 2012, either a successful canaloplasty (CP-Group, n = 24 eyes of 24 patients) or a successful implantation of a Schlemm's canal scaffoold ("Hydrus" HM-Group, n = 21 eyes of 21 patients) were reviewed. Canalopplasty was performed by using (a) a microcatheter (i-track) and (b) a viscodilation of the canal with high molecular wighht sodium hyaluronate (Healon GV). Only patients with at least a 24-month follow up available were analyzed. Analysis considered the changes in IOP, visual acuity (VA), Visual Field Mean Defect (MD), and number of hypotensive drugs between pre and post-op; differences in the rate of clinical failure, assuming failure as “the need, during follow-up, for either adjunctive glaucoma medications or a further glaucoma surgery”.
Results :
Preoperative IOP (mean±SD) was 26±4 mmHg in the CP-Group and 24±6 mmHg in the HM-Group (p=0.22). After 2 years, IOP decreased to 16±2 mmHg in the CP-Group and to 15±3 in the HM-Group (p=0.18). Final VA and MD did not change significantly in both groups. Two years after surgery, 50% of eyes in the CP-Group, and 33.3% of eyes in the HM-Group were without any adjunctive medications; 41.7% of eyes (10/24) in the CP-Group and 57.1% (12/21) in the HM-Group were on medications; 2 eyes required further glaucoma surgery in each group (p=0.52 for all distributions). No significant difference was found comparing the need of postoperative drugs in the two groups (p=0.73). A previous treatment with LTP was paralleled by a lower success rate in eyes exposed to canaloplasty (Fisher exact test, p < 0.05) . No effect of LTP on failure rate was observed in the HM cohort.(Fisher exact test, p > 0.4) .
Conclusions :
In the hereby presented retrospective comparative case series, CP and HM implant both achieved comparable and significant IOP reductions 24 months after surgery. The rate of clinical failure was also comparable between the two treatment groups. Previous laser trabeculoplasty proved a risk factor for failure only in those eyes exposed to CP.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.