Terrien’s marginal degeneration. A clinical case report

Background. Terrien’s marginal degeneration (TMD) is a rare corneal disorder. Accurate diagnosis is essential but often challenging due to its highly variable clinical presentation. Purpose: to present a clinical case of Terrien’s marginal degeneration. Case description. A 49-year-old male presented to the ophthalmology department at Perm Regional Clinical Hospital in August 2023 with complaints of growths on both eyes. Slit-lamp biomicroscopy revealed marked thinning of the inferior peripheral cornea in both eyes, accompanied by stromal scarring and conjunctival vascular ingrowth, forming a pseudopterygium. Autorefractometry showed against-the-rule astigmatism in both eyes. Anterior segment OCT of both eyes revealed a cavitary structure bounded by thinned corneal stroma and adjacent iris tissue. displaced anteriorly toward the cornea with the formation of iridocorneal synechiae in the anterior chamber angle bilaterally. Ultrasound biomicroscopy confirmed these findings. Based on the clinical history, comprehensive ophthalmologic examination, and anterior segment OCT data, a diagnosis of Terrien’s marginal degeneration complicated by corneal staphyloma was established. Conclusion. This clinical case of Terrien’s marginal degeneration in a 49-year-old male underscores the importance of accurate diagnosis. The disease course and clinical features are consistent with the limited published descriptions of this condition. Ancillary imaging techniques, including anterior segment OCT and ultrasound biomicroscopy, enhance diagnostic accuracy in atypical presentations. Patients with TMD require long-term ophthalmic follow-up.