The protective effect of early intraoperative injection of viscoelastic material in trabeculectomy.

In a prospective study, we evaluated the effect of intracameral injection of sodium hyaluronate (HA) in trabeculectomy on short- and long-term results, including the effect on the corneal endothelium. Twenty-two patients were randomly assigned into two groups: group A, consisting of 11 patients, underwent standard trabeculectomy; in group B (11 patients), additionally, HA was injected into the anterior chamber immediately following paracentesis in an attempt to minimize shallowing of the chamber after the subsequent trabeculectomy. Both groups had comparable age distributions, preoperative intraocular pressures (IOPs), preoperative endothelial cell counts, postoperative IOPs after 3 months, and glaucoma medication indices. The reduction in the number of endothelial cells after 1 month was significantly greater in group A than in group B (16.1% vs 6.7%). Also, significantly more shallow anterior chambers occurred in group A (three eyes vs one eye). However, 1 day postoperatively, the average IOP was 16.4 mm Hg in group A, as compared with 25 mm Hg in group B. Thus, although HA, injected early in trabeculectomy, appeared to protect against corneal endothelial loss and flat anterior chamber, it also seemed to be associated with early IOP spikes.