Automated standardized pupillometry with optical method for purposes of clinical practice and research

Abstract

The aim of the current study was the introduction and standardization of two experimental conditions for dynamic pupillometry. Pupillometry is a method that can provide valuable data concerning the functioning of the autonomous nervous system. The system for recording the pupil reaction was developed in the Laboratory of Clinical Neurophysiology of the 1st Department of Neurology of Aristotle University of Thessaloniki, in co-operation with the Laboratory of Fluid Mechanics of the Aristotle University of Thessaloniki. This system is fully automated. It includes an infra-red video camera, which has the capacity to record in complete darkness, and an SLE (clinical photic stimulator) lamp. A software application automatically performed all the procedures. During the first experiment, one flash was administered. During the second experiment, a series of 25 flashes (1 Hz frequency) was administered. Fifty physically and mentally healthy subjects aged 23-48 years took part in the study. Means, standard deviations and ranges for all variables characterizing normal subjects during both experimental conditions are reported. Test/re-test results and comparisons of the two eyes are also reported. The combined use of these two experimental conditions in dynamic pupillometry may be a very useful tool in medical research. There are already reports on the usefulness of pupillometry in the research of various diseases, including depression and Alzheimer's disease. It is expected that it will also be a valuable research tool in the study of diabetes, alcoholism, myasthenia gravis, cancer, multiple sclerosis, etc.

Dysfunction of the pupillary light reflex in experimental autoimmune autonomic ganglionopathy

“…We found that the response of the dark-adapted pupil to the first light stimulus was variable and often contaminated by movement artifact. After four conditioning light stimuli, the pupillary light response stabilized (figure 1A), an observation also seen in previous studies with human subjects (Fotiou et al, 2000). The last three pupillary light responses in the sequence were reproducible, and we used the average of these three responses for further analysis.…”

“…Likewise the ratio between the initial pupil diameter and the peak constriction is expressed as the relative peak constriction amplitude. Relative peak constriction amplitude is the most commonly used single quantitative measure of the pupillary light reflex (Fotiou et al, 2000).…”

“…Our observations in EAAG rabbits indicated that redilation latency is a useful parameter to detect early pupil abnormalities. The time to 75% redilation was less reliable than other measures but was included as a measure of sympathetic pupil function (Fotiou et al, 2000).…”

“…Pupillometry is a simple, relatively inexpensive, non-invasive technique that can be used to assess the functioning of both branches of the autonomic nervous system with minimal patient cooperation (Fotiou et al, 2000, Gavriysky, 1995, Piha and Halonen, 1994, Wachler and Krueger, 1999. Modern pupillometry systems use infrared digital video systems that automatically detect and measure pupil diameter with high temporal resolution.…”

Immediate effects of a thoracic spine thrust manipulation on the autonomic nervous system: a randomized clinical trial

“…14 Owing to the pupils exclusive autonomic innervation, more recently an interest has emerged to measure the pupil diameter to obtain a direct impression of autonomic function. [53][54][55][56] A dilation of the pupil is a result of simultaneous increasing activity of the sympathetic system and decreasing parasympathetic activity. 45,47,49 There is a lack in the literature accounting for some of the neurophysiological effects that seem to take place following manipulation techniques.…”