Trabecular meshwork bypass tube shunt: initial case series.

AIMS: This study describes a prospective consecutive case series of the initial six eyes of five patients undergoing implantation of the trabecular bypass tube shunt.
METHODS: A prospective consecutive case series. The initial six eyes of five patients with uncontrolled open angle glaucoma who had never previously undergone ocular surgery. Implantation of the trabecular bypass tube shunt measuring 150 micro m outer diameter and 50 micro m inner diameter was performed with the distal end placed in Schlemm's canal and the proximal end in the anterior chamber. The main outcome measures were visual acuity, intraocular pressure, glaucoma medication use.
RESULTS: The tube was successfully implanted in five of six eyes. In four eyes longer term follow up of 5-9 months showed no loss of visual acuity with decreased intraocular pressure from preoperative levels (mean 23.4-16.5 mm Hg) and reduced requirement of glaucoma medications (mean 3-0.5). In a subset of two eyes, there was no measured increase in aqueous flare or reduction of endothelial cell count. In one eye the tube was explanted because of presumed misplacement by excessive bleeding during surgery. Two eyes showed a diffuse bleb.
CONCLUSIONS: This study reports the initial experience with a novel approach to surgical glaucoma therapy. This very small tube allows a direct communication to be established between the anterior chamber and Schlemm's canal, effecting a trabecular bypass. In this small number of eyes this procedure reduced intraocular pressure and the need for glaucoma medications without appreciable side effects.