ABSTRACT
The re-introduction of non-penetrating surgery, such as non-penetrating deep sclerectomy29 and viscocanalostomy,30 has followed recognition of the need to avoid both the early and late complications noted above. Randomized controlled trials comparing both viscocanalostomy non-penetrating deep sclerectomy with trabeculectomy have shown that the trabeculectomy procedure is likely to provide lower IOPs (see Tan and Hitchings for review31).These studies have not been in existence for long enough to demonstrate that either viscocanalostomy can produce a lasting reduction in IOP, although sequential case series reported from both procedures suggest that a lasting reduction in IOP can be achieved.31
