The cornea is the clear window over the surface of the eye. It is the first barrier to infection and invasive microorganisms. The cornea has a barrier called the epithelium that is impervious to most infectious organisms. However, the corneal barrier may be violated by trauma, dryness, incomplete lid closure, or contact lenses. When this barrier is violated, there is a route for bacteria, fungi, and protozoa to enter the eye. Other times, the infection can be a virus suc