Ocular Decompression Devices: Liquid Mercury Balloon vs the Tungsten Powder Balloon

Abstract

Purpose: To determine if an intraocular pressure (IOP)-reducing device containing tungsten powder decreases pressure comparably to the traditional mercury-containing apparatus. Design: Prospective randomized, single-blind, controlled, phase I equivalence study. Method: At a tertiary care center, both eyes of 24 volunteers with normal IOP were treated with an ocular compression device containing either liquid mercury or tungsten powder. The IOP was measured at baseline and after 10 minutes of ocular compression. Results: The mean reduction in IOP was 3.6 mm Hg ± 2.0 with the mercury-containing device and 4.4 mm Hg ± 2.1 with the tungsten-filled apparatus. An equivalence study analysis using a paired t-test and a sequential analysis protocol did not demonstrate a statistically significant difference between the IOP-lowering effects of the two devices. Conclusions: The IOP-lowering effect produced by a tungsten powder-filled balloon ocular decompression device compared with a traditional mercury-containing device was not statistically different. © 2006 Elsevier Inc. All rights reserved.