It is the inflammation of the conjunctiva, like a large blister or containing fluid. When it is severe, the tissue becomes so swollen that the eyes cannot be closed properly. It is related to allergies or an eye infection or it can be a complication of eye surgery or it can occur from rubbing the eye too much.
Treatment: Cold compresses and lubricating drops to keep the eye hydrated. When it is caused by an allergic reaction, use antihistamines to control the allergic condition. If it is caused by a bacterial infection, it will be necessary to use antibiotics for at least seven days and keep the eyes at rest and avoid touching them with dirty hands.