Experimental endoscopic goniotomy. A potential treatment for primary infantile glaucoma.

PURPOSE: The purpose of this study is to determine if an endoscope would improve visualization of the anterior chamber angle and facilitate goniotomy in a surgical cloudy corneal model of primary infantile glaucoma.
METHODS: A 23-gauge needle coupled to a 0.8-mm diameter flexible endoscope entered the anterior chamber of porcine cadaver eyes through a corneal incision near the limbus. Internal structures were observed on a videoscreen and recorded as the needle approached and incised pectinate ligaments near Schwalbe's line. The eyes were then prepared for light microscopy and scanning electron microscopy.
RESULTS: Internal structures were clearly visualized on the videoscreen during the goniotomy. The incision of pectinate ligaments was accompanied by the iris falling back and opening of the trabecular meshwork compared with the untreated portion of the angle. This was confirmed histopathologically.
CONCLUSIONS: An endoscope coaxially coupled to a goniotomy needle tip allows visualization of the anterior chamber angle during goniotomy in the pig despite the presence of a cloudy cornea. The porcine anterior chamber angle is a useful animal model for studying the surgical treatment of primary infantile glaucoma.