Abstract :
It has long been recognized that visual damage may follow the administration of anesthesia. In 1937, Guedel noted “We still see too much conjunctivitis and traumatic keratitis following anesthesia”. The injuries at that time were attributed to open drop ether through a gauze covered mask in hard to handle subjects who half opened their eyes during light anesthesia (the patient was deemed in part responsible). A towel was customarily placed over the eyes and often became saturated quickly. Given that about 90% of anesthetics were produced by ether, mostly by an open or simple mask system throughout the first half of the 20th century, it is not surprising that serious corneal injuries were common but considered a small price to pay for a pain free surgical experience. Administration of gas through an oral tube was considered and rejected by John Snow in 1858 because he claimed that the tube fell out as the patient lost consciousness. Also, he considered his inhalation device via a mask with pliable sheet lead edges superior. The first use of tracheal tubes, a flexible gum catheter, was for resuscitation. The Scottish neurosurgeon, Sir William Macewen, described several cases in 1880 in which he admitted patients several days preoperatively to practice placement of an endotracheal tube before induction of chloroform anesthesia. But endotracheal anesthesia did not become general practice until after the development of the laryngoscope by Magill and others and the detachable blade by MacIntosh in 1941. The incidence of eye injuries decreased dramatically. Over the past two decades not only have short acting drugs been developed but the need to monitor oxygenation has been emphasized. Once more corneal injuries are prone to occur as patients, still partially anesthetized rub their eyes with fingers attached to a pulse oximeter.
