Download Relationship of the Relative Afferent Pupillary Deficit and

Previous Colloquia: 8th Colloquium
The eighth colloquium on the pupil was held in Detroit on May 25 and 26, 1973, hosted by Irene
Loewenfeld and Robert Jampel of the Kresge Eye Institute.
The vigor of this biennial colloquium is a tribute to the attractiveness of the pupil as an investigative
tool. It is not only an indicator of drug effects, of mental alertness and of the integrity of its associated
neural pathways but for bioengineers it is a visible example of a biological servo-mechanism. Part of
the attractiveness of the pupil must be this visibility; its movements and responses can actually be
seen. So, although the pupil is a less sensitive indicator of autonomic responses than peripheral blood
flow or the galvanic skin response, many psychologists prefer to work with the pupil; attracted I
suppose by its relative tangibility and by the reverberating rightness of something so visible being
within an organ of vision and seen through the experimenter's own pupils, etc.
Two British clinical pharmacologists with a longstanding interest in the pupil attended the meeting.
Paul Turner (St. Bartholomew's, London) described how he used the pupil as a model with which to
study and predict in humans the systemic actions of new drugs; and Stephen Smith (St. Thomas',
London) described his quantitative studies of tropicamide (Mydriacyl) penetration through the cornea.
The mechanisms of morphine miosis (increased parasympathetic outflow to the sphincter, due to
central disinhibition) were re-examined and confirmed by H. C. Lee and S. C. Wang (New York).
Interestingly, they found some pretectal cells which stopped firing after morphine and started up again
with a dose of the antinarcotic drug levallorphan.
Robert and Kathe Yoss (Mayo Clinic) reported further pupillographic studies on their patients with
narcolepsy.
David Newsome (Bethesda) and Irene Loewenfeld (Detroit) reported that pilocarpine impairs the light
reflex, whereas comparably miotic doses of methacholine and physostigmine do not; and that after
recovery from the miosis caused by a single drop of 2% pilocarpine, the response to light remains
reduced for 24 to 48 hours.
Ekhard Hess's (Chicago) oft repeated notion that the pupils get small when you dislike something, but
dilate when you like something, was firmly put down by his fellow psychologists, M. P. Janisse
(Winnipeg), Dieter Schwartz (Munchen), Arnold Lidsky, and Gad Hakarem (both of New York).
Hakarem's careful studies of pupillary responses to mental activity are exemplary.
Alan Laties (Philadelphia) discussed retinohypothalamic connections and the possible involvement of
the pineal gland in circadian rhythms. Shirley Wray (Boston) showed a videotape of a patient with
Wernicke's controversial hemianopic pupillary phenomenon. Irene Loewenfeld reported that Tournay's
phenomenon (anisocoria on lateral gaze) was seen occasionally in normal subjects. Glenn Fry
(Columbus, Ohio) analyzed some of the component waves of hippus in an attempt to find a correlation
with the discomfort a subject often experiences with constant light. Alan Schein (Philadelphia) studied
the unilateral mydriasis seen with laser irradiation of the eye. Heating of the iris and of the choroid and
other possible mechanisms were discussed. Roberta Pierson and Malcolm Carpenter (New York) reexamined the midbrain connections of the light reflex using tiny lesions and modern staining
techniques and found the pathways and interconnections to be a good deal more complex than
heretofore acknowledged.
Frank Shively (Winnipeg) compared the discharge patterns of cells in the lateral nucleus of the optic
tract in response to light stimuli to known pupillary behavior patterns.
Two separate groups (Arthur Loewy and F. N. L. Kerr, Mayo Clinic; M. C. Koss, - Oklahoma City; and
S. C. Wang, New York) reported detailed stimulation studies tracing the sympathetic (pupillodilator)
pathway down through the brainstem and cervical cord. They were in agreement that the main path is
ventrolateral in the brainstem and becomes lateral in the cord.
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Hans Borgmann (Trier, Germany) and Stanley Thompson (Iowa City) each gave papers on "Adies"
tonic pupil. The sector palsy of the sphincter and the visible changes in the iris stroma were
emphasized.
Louis Palumbo (Des Moines) pointed out that although the sympathetic fibers to the eye must pass to
the upper half of the stellate ganglion from the last cervical and first thoracic segments of the cord, the
lower half of the ganglion and the first thoracic ramus can be excised without producing Horner's
syndrome.
James Boyce and Myles Behrens (New York) presented a preliminary report on their study of the
diabetic pupil. Most of the younger and middle-aged patients' pupils dilated well to mydriatic drugs.
The bio-engineers, led by Larry Stark (Berkeley), John Semmlow (Chicago), and Stanley Day
(Cincinnati) concentrated their efforts on the dynamics of the near response. These pupil colloquia
seem to improve each year. The next one will be held in 1975 in Iowa City; the hosts will be the
Department of Ophthalmology, the University of Iowa, and myself.
H. Stanley Thompson
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