Pterygium with bulbar conjunctival hemorrhages.

BACKGROUND: This study was carried out to describe the clinical features and electron-microscopic characteristics of the capillaries in pterygium with conjunctival hemorrhage. METHODS: We compared the clinical findings in Japanese and Tunisian primary pterygia and in pterygium with and without bulbar conjunctival hemorrhages. The capillary fine structures of pterygium with bulbar conjunctival hemorrhages were studied by electron microscopy and compared with those without bulbar conjunctival hemorrhages. RESULTS: Conjunctival hemorrhages were noted in 16.4% of Tunisian patients but not in any Japanese patients. The former pterygia were significantly larger, more vascular and more frequently hyperemic than the latter. Pterygia with bulbar conjunctival hemorrhages were more hyperemic than without hemorrhages. Electron microscopy revealed interruptions of the endothelial cells and basement membrane of the capillaries in the pterygia with bulbar conjunctival hemorrhages, with blood cells escaping through the endothelial interruptions. CONCLUSION: Conjunctival hemorrhage in pterygia may be caused by fragility of the endothelial cells and basement membrane in the capillaries, which easily induces hemorrhage when the eyes are irritated by rubbing or by conjunctival foreign bodies. Pterygium with conjunctival hemorrhage is more frequently found in Tunisians than in Japanese.