Canaloplasty for open angle glaucoma: a three years critical evaluation and comparison with viscocanalostomy

Summary OBJECTIVE: Patients undergoing primary Canaloplasty for open angle glaucoma, under the care of the two authors, were entered into a common data base. The two authors also pooled their results at three years, from a prospective audit of patients undergoing Viscocanalostomy, from the same sites, in order to provide a comparison of the successes and complications of the two procedures. PATIENTS AND METHODS: Surgery was carried at: Warrington Hospital, Warrington, UK; Spire Cheshire Hospital, Stretton, UK; Augencentrum Porz, Cologne, Germany and University Eye Hospital Padua, Italy, between May 1997 and May 2008. Ninety seven eyes of 75 patients underwent Canaloplasty with a mean age of 67 years (range 41 to 85 years) and a mean follow up of 19 months (range 6 months to 3 years). One hundred and twenty eyes of 92 patients had undergone Viscocanalostomy with a mean age of 68 years (range 26 to 92 years) and a mean follow up of 22 months (range: 3 months to 3 years). RESULTS: There were no statistically significant differences in the mean pre-operative IOP and number of medications between groups. Both Canaloplasty and Viscocanalostomy groups showed a statistically significant reduction in IOP (t = 19.25. p < 0.05 and 15.54. p < 0.05 respectively) and number of medications (t = 21.18 p < 0.05 and 23.04 p < 0.05 respectively) from pre-operative levels. There was a statistically significant difference in favour of the Canaloplasty group in post-operative reduction of both IOP and number of medications compared with the Viscocanalostomy group (Mann-Whitney U 3940.5 and 4109.5 p = < .001 respectively). Of the 97 eyes that underwent Canaloplasty, using the criteria of success as ≤ 21 mm Hg, a success rate of 97% with medication and 92% with no medication was achieved. When success is defined at ≤ 17 mm Hg, the success rate was 87% with medication and 83% with no medication. For the 120 eyes undergoing Viscocanalostomy, using the criteria of success as ≤ 21 mm Hg, a success rate of 96% on medication and 55% with no medication was achieved. However, when success is defined at ≤ 17 mm Hg the success rate drops to 68% on medication and 42% with no medication. There was a statistically significant difference between groups in favour of the Canaloplasty group in the number of patients achieving a post-operative IOP of 17mm Hg or less (t = 2.55 p = .001). CONCLUSIONS: The results reported here show that both Viscocanalostomy and Canaloplasty are safe and effective s