The mucous membrane lining the inner surface of the eyelids also covers the front of the eyeball, although so transparent here that it is not apparent to the observer. Inflammation of this membrane is more commonly limited to that portion covering the inner surfaces of the lids, but may extend to the eyeball when the eye becomes “bloodshot” and the condition more serious. For the sake of convenience we may speak of a mild form of sore eye, as congestion of the eyelids , and the more severe type, as true conjunctivitis