<i>C. mast</i> (IMAGE) NIH/National Eye Institute Caption C. mast is a commensal bacterium living on the surface of the eye. Credit Rachel Caspi and Anthony St. Leger Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.