The edrophonium (Tensilon) tonogram was devised to magnify the objective response of paretic extraocular muscles to a test dose of an antimyasthenic agent. While the intravenous administration of edrophonium chloride (Tensilon), as a rapid diagnostic procedure for myasthenia gravis is widely practiced, edrophonium tonography represents a sensitive refinement in recording the myasthenic response. In cases of subtle and confusing ophthalmoplegia, the value of this procedure may be of diagnostic significance. Derivatives of physostigmine had been used therapeutically by Walker1,2 and others,3-6 but the diagnostic value of a rapid test was not emphasized until Osserman and Kaplan7 described the intravenous use of edrophonium. This analogue of neostigmine is a rapid anticurare agent whose maximum effect occurs within one minute. Breinin8 has evaluated anticholinesterase and anticurare agents by use of electromyography. He suggests the occurrence in myasthenic patients of characteristic innervation patterns and drug response patterns. Kornblueth et