Purpose: To compare the acute effects of Healon (sodium hyaluronate) and Viscoat (sodium chondroitin sulfate-sodium hyaluronate) on outflow facility in human cadaver eyes and determine which viscoelastic agent is least likely to cause an intraocular pressure (IOP) spike after cataract surgery.
Setting: The Glaucoma Research Lab, University of Toronto, Ontario, Canada.
Methods: In this prospective paired study, 15 pairs of human cadaver eyes were used. Following the construction of a 3.0 mm scleral tunnel, 0.25 cc of Healon was injected into the anterior chamber of 1 eye and 0.25 cc of Viscoat was injected into the contralateral eye. The viscoelastic agents were removed from both eyes in a standardized fashion and the scleral tunnels closed. The eyes were then perfused at a constant IOP of 8.0 mm Hg, corresponding to 16.0 mm Hg in vivo. Outflow facility (microL/minute [min]/mm Hg) was recorded every 15 minutes for 24 hours using standard methods.
Results: Outflow facility in the Viscoat-treated eyes decreased appreciably for the first 3 hours, then recovered somewhat after 12 hours; facility in the Healon-treated eyes showed less of an overall decrease. Over the 24 hour perfusion period, mean outflow facility was 0.037 microL/min/mm Hg +/- 0.015 (SD) in the Viscoat-treated eyes and 0.060 +/- 0.012 microL/min/mm Hg in the Healon-treated eyes. Healon reduced outflow facility significantly less than Viscoat between 3.25 and 10.50 hours postoperatively (P < .05, 2-tailed t test).
Conclusions: Healon reduced outflow facility less than Viscoat between 3.25 and 10.50 hours postoperatively.
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