Anatomopathological Aspects and Clinical Correlation of Conjunctival Bleb Fibrosis Following Encapsulation of a Biodegradable Collagen Matrix Implant in Glaucoma Surgery.
Luisa Castro-Roger, Sara Labay-Tejado, Xavier Suárez et al.
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Case in brief
Four patients with progressive glaucoma and inadequate intraocular pressure control despite maximal medical therapy underwent non-penetrating deep sclerectomy with a biodegradable collagen-glycosaminoglycan implant and adjunctive mitomycin C. Each developed progressive bleb fibrosis requiring surgical revision. Histology of excised tissue showed the implant intact and surrounded by dense fibrotic tissue, with extensive collagen deposition and minimal fibroblast infiltration. The implant showed no significant degradation for up to three years. The authors suggest that patient-specific fibrotic predisposition may contribute to variable tissue responses and surgical outcomes.
What made this case unusual
Despite being designed to limit fibrosis, the implant remained intact within a dense fibrotic capsule—the described “ring-of-steel” appearance—with minimal fibroblast infiltration and no significant degradation for up to three years.
Diagnostic / clinical pearl
When a bleb fails after this procedure, histological examination may show dense encapsulation of an intact collagen-glycosaminoglycan implant rather than substantial implant degradation.
Why it matters
The findings suggest that tissue response to the implant may vary and that patient-specific fibrotic predisposition could be relevant to surgical outcomes.