FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-65/9

Title and Subtitle: Pupillary movements during acute and chronic fatigue: a new test for the objective evaluation of tiredness.

Report Date: April 1963 (reprint)

Authors: Lowenstein O, Feinberg R, Lowenfeld IE.

Abstract: Spontaneous pupillary movements in darkness were recorded in

1. healthy subjects of different ages when they were rested or fatigued,
2. chronically tired subjects without known neurological defects, and
3. patients with various neurological lesions.

In some of the experiments, local or systemic drugs were used. While the pupils are large and quiet in darkness when the subject is alert, they oscillate under the influence of tiredness. Waves of spontaneous pupillary contraction and dilation accompany periods of increasing sleepiness and spontaneous arousal until, at the moment immediately preceding sleep, the pupils become very small. The mechanism of these movements was analyzed and a simple test described which allows the objective determination of the degree of acute fatigue in a given subject at a given time. In the light of these results, the concepts of 'normal' and of 'pathologic' fatigue were discussed.

Note: this document is a reprint of Investigative Ophthalmology 1963;2(2).

Key Words: fatigue (physiology), photosensitivity(biological), photosensitivity (biological), fatigue (physiology), eye, pathology, oscillation, sleep, stimulation (physiology), drugs, muscles, relaxation(physiology), reflexes, central nervous system, emotions.

No. of Pages: 18