Saccadic eye movements were observed and recorded by electrooculography and a limbal sensing device (Eye Trac) in patients with lateral rectus palsies. These movements were produced voluntarily by shifting fixation or involuntarily in the recovery phase of optokinetic nystagmus. Visual inspection of the eye movement and study of the recordings indicated that the speed of eye movement as the result of contraction of a normal muscle was significantly greater than the speed of eye movement caused by contraction of a paretic muscle. The simplicity of this technique, availability and lack of discomfort, and the ability to perform and interpret the test in the office, make it clinically useful as a guide to the presence and amount of paralysis.
Metz HS, Scott AB, O'Meara D, Stewart HL. Ocular Saccades in Lateral Rectus Palsy. Arch Ophthalmol. 1970;84(4):453-460. doi:10.1001/archopht.1970.00990040455010