A procoagulant effect was reported previously after injection of 0.50 to 0.75 ml of sodium hyaluronate (Healon) into the vitreous cavity at the end of phakic diabetic vitrectomies. A multicenter, randomized, prospective trial was done to study this effect. In the treatment group the media was clear in 50% of eyes in the immediate postoperative period compared with only 8% in the control group. At 2 to 6 weeks, there was no statistically significant difference between the two groups. The authors conclude that such sodium hyaluronate injection provides clear media in a significant number of eyes in the immediate postoperative period, potentially allowing thorough postoperative evaluation and early retinal photocoagulation if needed.