Can perforations of descemet's window (DW) improve the outcome of canaloplasty in open angle glaucoma?

Purpose: This study evaluates whether additional opening of the descemet's window (DW) in canaloplasty has a positive effect on the intraocular pressure (IOP), glaucoma medication, visual acuity and postoperative complications and further interventions within the subsequent 12 months. This study also compares the difference of myopia and non-myopia based on the respective surgical method, as well as the quality of life after surgery by means of a questionnaire.

Patients And Methods: This retrospective study included 114 patients who had a complete ophthalmic examination at baseline, as well as the first post-operative day and at 1, 3, 6, and 12 months following the procedure. The patients were divided into three groups: group 1 with intact DW (n = 35), group 2 with accidental rupture of the DW (n = 40), and group 3 with scheduled puncture of the DW (n = 39). Main outcome parameters were IOP reduction and the number of IOP-lowering medications. Intraoperative and postoperative complications were documented systematically.

Results: With a follow-up period of 12 months, all three groups showed statistically significant reductions in mean IOP and number of glaucoma medications as compared with preoperative values. At 12 months, group 1 (group 2/3) had a mean IOP reduction of 27.3% (33.1%/36.3%) and medication use reduction of 75% (82.6%/91.7%). Comparing the three surgical groups, there was no significant difference in terms of reduction of IOP and medication (p > 0.05) at all time points. Surgical complications were similarly rare. The number of subconjunctival blebs was statistically significantly different in the three groups (p < 0.05; group 1, 0%; group 2, 15%; group 3, 12.8%). Only in group 1, a revision after surgery was necessary in three cases. A significant difference concerning IOP, medication use, and visual acuity was not found between myopic eyes and non-myopic eyes after canaloplasty. The postop-surgical questionnaire showed that with 90.5% in group 1, 88.5% in group 2, and with 90.5% in group 3, the patients were highly satisfied with the results of surgery.

Conclusion: The intraoperative scheduled puncture of the DW in tendency showed better but no statistically significant results after 1 year regarding lowering of the IOP, the visual acuity, and postoperative medication usage. In addition, no increased risk of complications was observed in the myopic eye after the opening of the DW.