Those who suffer from conjunctivitis, their conjunctiva is either inflamed or irritated. It partially covers the eyeball and is located on the inside of the eyelid. When inflammation is present, the blood vessels fill up more, causing the affected eye to be red and swollen.
Conjunctivitis can have a variety of causes. Infections by viruses or bacteria, allergies and even chemical or mechanical irritations (e.g. draught, dust) can be triggers. The most common sufferers are children, while the treatment depends entirely on the cause.