Curare in ocular surgery; report of 25 cases.

CURARE, a drug extracted from two main plant sources of the natural orders Manispermaceae and Strychnos, was formerly obtained from S. American Indian tribes who used it as an arrow poison in hunting and warfare. The drug acted by paralysing the victim, a large enough dose being rapidly fatal. The important active principle (C38 H44 06 N2) is designated d-tubo-curarine.t From the ophthalmologist's point of view, the special value of curare lies in its selective sequence of paralysis, affecting first the muscles innervated by cranial nerves, then the extremities, and lastly the trunk and respiratory muscles. Roche (1950) described the following sequence: transient blurring of vision, facial flaccidity, ptosis, paresis of the vertical ocular muscles followed by that of the horizontal group, relaxation of jaw, pharynx, larynx, cervical muscles, and horizontal rotators of the globe. The ocular muscles are the first to be affected and the last to recover. The judicious use of curare enables the cataract surgeon to perform his task with greater delicacy and precision, since it renders the patient and his eyes quiet and relaxed. The rigidity and muscular spasm which may be caused by apprehension, fear, or worry, or may be reflex to pain and discomfort, are the source of many complications in cataract surgery, but although these disadvantages of local anaesthesia have long been recognized the risks attendant upon general anaesthesia are even greater. The search for an agent which would overcome muscular spasm and rigidity in general anaesthesia, and which would permit the lightening of such anaesthesia, has led to the application of the akinetic drugs of the curare group. Curare has been employed in general surgery for the last 8 years, but its use in ophthalmology was reported first by Kirby (1949) and a little later by Clark (1949).