Conjunctivitis, or pink eye, is an inflammation of the conjunctiva.
This is the thin clear tissue that lies over the white part of the eye and lines the inside of the eyelid. It is most common amongst children to get it a lot, and it can be highly contagious (it spreads rapidly in schools and daycares), although uncomftable it is not often serious. It is not likely to damage your vision, especially if it is treated quickly. Take care to prevent its spread and do all the things your doctor recommends, pinkeye clears up with no long-term problems.