Since the discovery of the Argyll Robertson or fixed pupil in 1869, many attempts have been made to explain the loss of the pupillary reactivity to light in this syndrome. In the majority of these the fixed pupil has been accounted for on the basis of a central interruption of the afferent path of the light reflex somewhere along its course to the oculomotor nucleus. A knowledge of the central course of the pathway of the light reflex has, therefore, assumed major importance for an explanation of the Argyll Robertson disorder, and in most of the publications on this subject either clinical or experimental evidence bearing on the localization of this pathway has been presented.
Extensive as this literature has been, it has not furnished satisfactory evidence concerning the course of that part of the arc situated within the interior of the brain, because this part of the arc
MAGOUN HW, RANSON SW. THE AFFERENT PATH OF THE LIGHT REFLEXA REVIEW OF THE LITERATURE. Arch Ophthalmol. 1935;13(5):862–874. doi:10.1001/archopht.1935.00840050140015