Surgical alternative to trabeculectomy.

Non-penetrating glaucoma surgery, represented by deep sclerectomy and viscocanalostomy, is an effective method to lower intraocular pressure (IOP) in glaucomatous patients. Both procedures reduce IOP by allowing aqueous humor drainage without opening the anterior chamber. Deep sclerectomy, similar to trabeculectomy, provides aqueous external filtration in the subconjunctival space. This technique, with the adjunctive use of implants, antimetabolites, and goniopuncture, may provide final IOP comparable to those obtained with trabeculectomy, but with less complications. Viscocanalostomy is less dependent on external filtration since it increases trabecular aqueous outflow facility by micro-disrupting Schlemm's canal walls and juxtacanalicular trabecular meshwork. This technique is very safe, but it provides higher final IOPs compared to trabeculectomy. Non-penetrating surgery should be therefore considered a surgical alternative to trabeculectomy in specific clinical cases.