Purpose:
To report a case of Streptococcus mitis oralis (S. mitis/oralis) corneal ulcer in a patient with a possible preventable cause.
Methods:
Cultures were obtained from a 64-year-old woman with a 3.5 mm × 5 mm corneal ulcer with hypopyon in the left eye.
Results:
Culture reports demonstrated the growth of S. mitis/oralis, a commensal organism of the oral flora. Fortified vancomycin 5% eye drops were started, and the patient was counseled on the rarity of the bacteria as an etiology of corneal ulcers. On the return visit, the patient, who works in a doctor's office, volunteered information that the preservative free artificial tear vials that she used were difficult to open because of her hand deformity due to rheumatoid arthritis; thus, she had to bite the vials open.
Conclusions:

S. mitis/oralis is an organism commonly found in the mouth but is rarely found in the eye. We report a unique case of an immunocompromised patient with rheumatoid arthritis, severe dry eye, and a history of multiple episodes of keratolysis, who developed a corneal ulcer from a rare pathogen, with a plausible and preventable route of infection.