The velocity of saccadic eye movements was recorded by electrooculography in myasthenic and control subjects before and after edrophonium chloride (Tensilon) administration. Increased saccadic velocity and an increase in frequency and amplitude of the optokinetic nystagmus followed edrophonium administration in the myasthenic subjects. No changes occurred in the control subjects. Saccadic velocity testing in myasthenia gravis can be performed simply and rapidly. The eye movement study must be made in the direction of the apparent ocular motor weakness. The test is free of discomfort and provides a sensitive, objective response. It is indicated when ocular motor function improvement is judged equivocal by the subject or by the examiner grossly observing eye movements.
Metz HS, Scott AB, O'Meara DM. Saccadic Eye Movements in Myasthenia Gravis. Arch Ophthalmol. 1972;88(1):9-11. doi:10.1001/archopht.1972.01000030011003