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18 2. Pupillary reactions elicited from the fovea and from the retinal periphery 53 (a) Influence of experimental procedure 56 (b) Criteria of pupillary responsiveness 57 (c) Pupil perimetry 57 Stimulus Color 58 1 . The literature 58 2 . Pupillary spectral sensitivity 60 Other Features of Pupillary Reactions to Light 65 1. Adaptation 65 (a) Adaptation to darkness 65 (b) Light adaptation 65 2. Effect of the entrance pupil 67 3. Binocular interaction 67 THE PUPILLARY REACTION TO NEAR VISION 69 CONCLUSIONS 77 BIBLIOGRAPHY , 80 As in all chapters of the literature on the pupil, there have been controversies concerning the role of the pupil in connection with both (1) the perception of light and (2) near vision. The chief questions raised about the first subject relate to the identity of the receptors for the light reflex: even today some authors hold that the rods play no pupillomotor role, while at the same time, the pupillary spectral sensitivity has been reported to show a scotopic curve even under photopic conditions (Bouma, 1962). As to near vision, the relations between accomodation, con- vergence, and the pupil have been discussed at length. It is the purpose of the present paper to give a reasonably concise experimental review of this literature, and to see what general conclusions can be drawn from it at this time. Criteria for Selection of Papers In all surveys of the literature, reviewers are faced with two main difficulties: they have to decide where to draw the limits that will outline the subject at hand most effectively, and they have to bear the nagging awareness that their material may be not at all complete. Were there more time to search for additional material, a large group of papers of most direct interest might be discovered around the next corner.. . In the present case, then, the publications presented are the ones available to the author at this time, which have as their chief subject either pupillary movements related to the retinal receptor mechanism, or pupillary movements related to near vision. It should
17 PUPILLARY MOVEMENTS ASSOCIATED WITH LIGHT AND NEAR VISION1 An Experimental Review of the Literature Irene E. Loewenfeld Department of Opthhalmology, Columbia University College of Physicians and Surgeons and Presbyterian Hospital, New York \ TABLE OF CONTENTS INTRODUCTION 18 CRITERIA FOR SELECTION OF PAPERS 18 PUPILLARY REACTIONS TO LIGHT 20 Stimulus Intensity 20 1. The literature 20 2. Features of the reactions to light of different intensities .. 24 3. Modifying effects of fatigue and emotional excitement 24 Time Characteristics of the Stimuli 37 1. The literature 37 2. Influence of stimulus duration 37 (a) Moderate intensity range 37 (b) Threshold reactions 39 (c) Very strong light 39 (d) Stimulus duration in clinical examinations of the pupil .. 40 3. Influence of stimulus frequency 41 4. Sinusoidal stimuli 42 5. Other time characteristics of pupillary reactions to light . 42 (a) Pupillary movements which occur during steady illumination 42 (b) The darkness reflex 47 (c) The latent period 48 Stimulus Area (Spatial Summation) 49 Retinal Location of the Stimuli 52 1. The literature 52 1 This work was supported by the Harriman Fund and by grants from the U.S. Public Health Service (NB 00253 and 5-K3-NB-16, 542-01).
