Purpose: The purpose of this study was to investigate the role of Staphylococcus aureus in the onset of ocular catarrhal ulcers.
Methods: We examined the colonization by S. aureus of the ocular surface (conjunctival sac, upper and lower lid margins) of 3 patients with catarrhal ulcers and analyzed the S. aureus isolates by pulsed-field gel electrophoresis.
Results: S. aureus organisms were found on the lid margin of all eyes affected by catarrhal ulcers. The contralateral eye without ulcers harbored S. aureus exhibiting a pulsed-field gel electrophoresis pattern identical to that of the affected eye.
Conclusions: Although S. aureus on the lid margin plays an important role in the onset of catarrhal ulcers, its presence is one among several risk factors.