Application of hyaluronidase after unsuccessful trabeculectomy

Trabeculectomy fails to control the intraocular pressure (IOP) adequately in some cases. The effect of the enzyme hyaluronidase--300 IU Hylase 'Dessau' (commercially available ampuls)--applied in subconjunctival injection in the region above the filtering bleb in case of postoperative rise in IOP following trabeculectomy was studied. Successful IOP control was defined as an IOP below or equal to 20 mmHg with or without medication. The investigation concerned 62 eyes (46 patients) with primary open angle glaucoma (POAG) divided in three groups: Group I--39 eyes with early postoperative rise in IOP (7-20 days postoperatively), group II--15 eyes with late rise in IOP (6 months-1 year after surgery), group III--8 eyes with one previous unsuccessful trabeculectomy. In all examined cases IOP was over 20 mmHg (mean IOP was 26.23 +/- 3.46 mmHg) postoperatively before application of hyaluronidase. The follow up period ranged from 6 to 34 months. We found statistically significant lowering in IOP in group I (p < 0.01), group II (p < 0.05) and group III (p < 0.05). Complications related to the use of hyaluronidase were not observed up to now. Postoperative subconjunctival injection of hyaluronidase appears to improve the prognosis following unsuccessful trabeculectomy in POAG patients.