The cause of simple glaucoma remains unknown. It cannot even be stated whether the primary cause should be sought within the eye itself or outside the eye, as in the nervous system, or in both.
A series of observations point to the probability that disturbances of the central nervous system are to be considered among the pathogenic factors of glaucoma. Thus it seems justifiable to take a stand on the question whether the disturbances of pupillary reaction, which so far have been present in all cases (about 40) of glaucoma studied, are of central origin or whether they originate in secondary modifications of the receptor or effector organs in the eye.
In this paper we present the results of pupillographic studies in which one eye was clinically unaffected. The question arises : How do the pupillary reflexes of the seemingly normal eye behave, and what is the significance of their behavior?
LOWENSTEIN O, SCHOENBERG MJ. PUPILLARY REACTIONS OF THE SEEMINGLY UNAFFECTED EYE IN CLINICALLY UNILATERAL SIMPLE GLAUCOMAPUPILLOGRAPHIC CONTRIBUTIONS TO DIAGNOSIS OF GLAUCOMA IN THE PRECLINICAL STAGE. Arch Ophthalmol. 1944;31(5):392–398. doi:10.1001/archopht.1944.00890050042004