A case of spontaneous avulsion of primary pterygium analyzed with anterior segment optical coherence tomography

PURPOSE: This study reports a case of the spontaneous avulsion of primary pterygium with anterior segment optical coherence tomography (AS-OCT) findings. OBSERVATION: A 72-year-old woman complained of acute pain of the left eye. Primary pterygia were noted in both eyes on the initial examination 4 months ago. Slit-lamp microscopy revealed a nasal corneal epithelial defect, and the rolled elevated lesion in the corneal limbus of the left eye. She was diagnosed with a spontaneous avulsion of the corneal pterygium head. Then the avulsed pterygium head slowly recurred. The pterygium head of the fellow eye had a yellow-whitish elevated lesion beneath the epithelium with poor vascularity. AS-OCT revealed hyper-reflective foci beneath the epithelium corresponding to the yellow-whitish elevated lesion. CONCLUSIONS/IMPORTANCE: The present case revealed the spontaneous avulsion of the pterygium head leading to the corneal epithelial defects and ocular pain, while the pterygium head of the fellow eye showed subepithelial hyper-reflective foci suspicious of spheroidal degeneration on AS-OCT. In this case, the cause of spontaneous avulsion of the pterygium head might be potentially weak adhesion to the cornea due to spheroidal degeneration. PRECIS: This case is a primary pterygium leading to spontaneous avulsion, in which hyper-reflective foci were noted in OCT.