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December 1954

ALTERNATING CONTRACTION ANISOCORIA: A Pupillary Syndrome of the Anterior Midbrain

Author Affiliations


From the Department of Ophthalmology (Laboratory of Pupillography), Columbia University College of Physicians and Surgeons, and the Institute of Ophthalmology, Presbyterian Hospital.

AMA Arch NeurPsych. 1954;72(6):742-757. doi:10.1001/archneurpsyc.1954.02330060078010

AMONG THE clinical cases examined in this laboratory a relatively large group showed a pupillary syndrome which I have named alternating contraction anisocoria. I have used the term contraction anisocoria in order to describe the appearance of inequality of the pupils under the influence of a pupilloconstrictor stimulus, such as light, while the term alternating is used because there is a variation as to which pupil becomes smaller. In alternating contraction anisocoria the pupil of the stimulated eye always contracts more extensively than does the consensually reacting pupil of the opposite side.

Many neurologists and ophthalmologists believe that pupillary inequality due to uneven illumination is a physiological phenomenon. Pupillographic records do not agree with this view. Apparent inequality of the pupils results from an optical illusion on the part of the observer, whereby the pupil of the dimly lighted eye seems larger than that of the brightly illuminated one. Furthermore,

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