Ab-interno trabeculo-canalectomy: surgical approach and histological examination.

PURPOSE: To evaluate, on eye bank eyes, a new surgical approach aimed at removing a quadrant of the trabecular meshwork (TM), with an ab interno approach. METHODS: Gonioscopically controlled ab interno removal of the TM was done with a subretinal forcep on six human bank eyes. Serial histological sections were obtained from the treated and untreated part of each globe to assess the effect of the technique on intraocular tissues. RESULTS: Under the gonioscope, the TM was easily removed in strings of varying length. Histological examination showed, unexpectedly, that this resulted in a well-defined deep furrow in the middle of the trabecular region involving both the TM and the inner wall of Schlemm's canal. The operation created a direct communication between the anterior chamber and Schlemm's canal lumen without any evident damage to the outer canal wall and adjacent ocular structures such as the iris base and corneal endothelium. CONCLUSIONS: Our small series on human bank eyes showed that the procedure involves both the TM and the inner wall of Schlemm's canal and is therefore called ab interno trabeculocanalectomy (AITC). The intraoperative findings and the histological evidence are encouraging, and suggest that the procecedure could have potential clinical application.