The symptoms of conjunctivitis will depend on the cause, but generally they include:
•eye redness: this happens as a result of the inflammation and widening of the tiny blood vessels in the conjunctiva (thin layer of cells that covers the front of the eyes)
•watering eyes: the conjunctiva contains thousands of cells that produce mucus and tiny glands that produce tears – inflammation causes the glands to become overactive, so that they water more than usual
Although only one eye tends to be affected at first, symptoms usually affect both eyes within a few hours.