I’ve never heard of conjecture Vitus. Perhaps you mean conjunctivitus, which is inflammation of the eye? There are many things which can cause this sort of inflammation, but the most common are infections and allergies.
I’m not sure of conjecture vitus either. If it is conjunctivitis then there can be bacterial and viral causes. My son gets conjunctivitis a lot and our GP thinks it is just a virus he can’t shift. It usually goes away on its own.