Videopupillometry

Videopupillometry is a non-invasive method used to measure the reflexes of the pupil in response to visual stimuli. The technique involves recording changes in pupil size and shape using a high-speed camera, typically at a rate of 30-60 frames per second. The recorded video is then analyzed to extract key parameters such as pupil diameter, area, and constrictory latency.

Videopupillometry is particularly useful in the assessment of autonomic nervous system function, particularly in the context of diagnosing disorders that affect the sympathetic nervous system, such as multiple system atrophy or parkinson's disease. The method has also been applied in the study of attention and cognitive processes, as well as in the evaluation of patients with sleep disorders.

The technique relies on the principle that the pupil responds reflexively to changes in the intensity of light. In a standard session, the subject is seated in front of a screen displaying a sequence of light stimuli, which may include various patterns of intensity and duration. The subject's pupils are recorded as they respond to each stimulus, and the data are analyzed using specialized software to calculate relevant parameters.

Videopupillometry presents several advantages over traditional pupilometry methods, which rely on static measurements of pupil size. The high-speed recording capability of videopupillometry allows for the capture of subtle changes in pupil dynamics, providing a more comprehensive understanding of autonomic and cognitive functions. However, the technique requires specialized equipment and expertise to implement and analyze effectively.