A randomized masked study was performed to compare Healon GV, a new higher molecular weight sodium hyaluronate viscoelastic, with Healon in extracapsular cataract surgery with posterior chamber intraocular lens insertion. Seventy patients were randomly divided into two groups. Postoperative intraocular pressures, pachymetry, endothelial cell counts and morphology, amount of viscoelastic and irrigating solution used, difficulty of surgery, and postoperative flare and cells were measured. Postoperative pressures were not significantly different between the Healon and Healon GV treatment groups, except at the eight-hour observation period, when the pressure was higher in the Healon GV group (P = .02). There was a significant (P = .002) reduction in the amount of viscoelastic required in the Healon GV group. Cell counts and morphology were not significantly different between the groups. Other parameters showed no significant difference. Clinically, Healon GV handled like Healon during instillation into the anterior chamber and aspiration at the end of the case. It did, however, appear to be much more effective at maintaining the anterior chamber, as demonstrated in the smaller amount of viscoelastic required.