Objective: To show tissue changes using ultrasound biomicroscopy (UBM) in eyes with controlled intraocular pressure (IOP) after viscocanalostomy.

Methods: Consultores Oftalmológicos, Fundación Oftalmológica Argentina Jorge Malbran and Hospital Santa Lucía, Buenos Aires, Argentina. Methods: This retrospective noncomparative case series comprised 23 eyes of 19 patients with uncontrolled open-angle glaucoma who had viscocanalostomy and UBM and a mean follow-up of 20 months +/- 5.9 (SD) (range 12 to 30 months). The UBM measurements were taken a mean of 6.8 +/- 5.9 months (range 3 to 14 months) after the viscocanalostomy. In 7 eyes, UBM was again performed a mean of 7.8 +/- 4.6 months (range 7 to 9 months) after the first study. All patients had preoperative and postoperative IOP measurements.

Results: The mean IOP at last examination was 13.3 +/- 2 mm Hg (range 8 to 17 mm Hg). One eye had evidence of a subconjunctival bleb. All eyes had a nonreflective scleral chamber and posterior to it, a hyporeflective zone. In 7 eyes in which 2 UBMs were performed, the scleral chamber was unchanged 7 to 9 months after the first study.

Conclusions: The presence of a scleral chamber and absence of a subconjunctival filtering bleb are the usual UBM findings in eyes with adequate control of IOP several months after viscocanalostomy. These findings suggest that viscocanalostomy is successful when a continuous aqueous flow through the trabeculo-Descemet's membrane is present, maintaining a scleral chamber.