The effect of learning curve on the surgical outcome of viscocanalostomy

To evaluate the influence of learning curve on the surgical outcome of viscocanalostomy.

Retrospective, interventional study. Chart review of the first consecutive open-angle glaucoma cases that received viscocanalostomy in 1 institution between July 1996 and June 2000. Overall success was defined as no visual field deterioration; postoperative intraocular pressure (IOP) ≤20 mm Hg; and IOP reduction ≥30% compared with baseline values with or without medication. When medications were not required, success was defined as complete. Demographic, procedural, and postoperative data were tabulated and analyzed.

overall and complete success rates.

number of glaucoma medications and surgical complications.

A total of 180 cases were analyzed. Mean follow-up (±SD) was 28.9±5.9 months (range, 12-36 mo). Overall success has significantly improved from 64% to 91% when comparing the first 45 to the last 45 cases of the series (Mantel-Cox, P=0.005). Similarly, complete success has significantly improved from 38% to 73% (Mantel-Cox, P=0.004). The mean number of glaucoma medication (±SD) significantly decreased from 2.58±0.94 before surgery to 0.53±0.79 after surgery (Wilcoxon, P<0.001). Surgical complications decreased from 16 in the first 45 cases to 10 in the last 45 cases without reaching statistical significance (Pearson χ, P=0.315).

Viscocanalostomy appears to safely reduce IOP in cases with medically uncontrolled open-angle glaucoma. Mastering viscocanalostomy procedure is achievable after the first 40 cases.