[A case of encapsulated filtering bleb after trabeculectomy].

A case of encapsulated filtering bleb after trabeculectomy is reported. A 57-year-old man with primary open angle glaucoma underwent a trabeculectomy one year ago. Six months after the operation the filtering bleb began to shrink and intraocular pressure (IOP) began to rise. It was suspected that the trabeculectomy site was obstructed by scarring, and so sclerostomy ab interno was performed in the site with a Nd: YAG laser. The IOP was higher elevated, however, and the bleb remained unchanged with severe conjunctival injection and aqueous inflammation. The next day trabeculectomy was performed in a new site and two weeks later a dome-shaped, prominent bleb was observed with an increase in the IOP. This was diagnosed as an encapsulated filtering bleb (Tenon's capsule cyst). Cystectomy of the bleb failed and it recurred, therefore, another trabeculectomy was added and the IOP was kept at a reasonable value. We believe that it is important to pay attention to an encapsulated filtering bleb as a complication of filtering surgery after laser therapy to the anterior chamber angle.