Recently, biodegradable collagen matrix has been used as a possible substitute for anti-metabolite in trabeculectomy in order to control the responsiveness of the wound healing process. This paper reports a case of encapsulation of the biodegradable collagen matrix after trabeculectomy.

We conducted a fornix-based trabeculectomy on a 58-year-old man with medically uncontrollable steroid-induced glaucoma. We implanted biodegradable collagen matrix onto the sclera flap beneath the conjunctiva. Immediately after the surgery, we observed a localized bleb with high elevation. In the three months of follow-up, the bleb became encapsulated, and an increase in intraocular pressure was noted. During the wound revision, encapsulated material surrounded by thick fibrous membrane was found and removed from the subconjunctival space, followed by biopsy. Biopsy results demonstrated that amorphous collagenous material was surrounded by spindle and inflammatory cells.

It is important to note that the fibrous encapsulation of collagen material is a possible complication of biodegradable collagen matrix-augmented trabeculectomy.