Terrien’s marginal degeneration (TMD) is a rare, slowly progressive, non-inflammatory peripheral corneal thinning disorder that may lead to spontaneous perforation in advanced stages.

We report the case of a 33-year-old man with bilateral peripheral corneal thinning and a spontaneous inferior perforation in the right eye. Slit-lamp examination revealed 360° peripheral stromal thinning with superficial neovascularization and lipid deposition. Seidel’s test was positive in the right eye. The diagnosis of Terrien’s marginal degeneration was made after exclusion of infectious and autoimmune causes. A tectonic, crescent-shaped, lamellar peripheral keratoplasty was performed to restore globe integrity. Postoperative follow-up showed resolution of leakage, improved corneal stability, and partial visual recovery.

Corneal perforation in Terrien’s marginal degeneration represents a therapeutic challenge. Peripheral lamellar tectonic grafting is an effective surgical option to preserve ocular integrity while maintaining central transparency and visual potential.