Ulcers do not look the same as blood vessels. They will appear as small white dots or may not be visible at all. When the eye is "stained" it is done so using flourescene (sp). They look at the eye with a light that helps them see what has been stained. The florescene stains viruses that may be infecting the eye, like herpetic infections, etc. The shape of the virus stained enables them to tell what type it is, how they need to treat it, if it is contagious, etc.
I would think that with greenish discharge, it is more likely an infection that an ulcer. |