A Guide to the Design of Electropupillometer

Abstract

The design method of closed-circuit TV pupillometer is discussed, especially from two viewpoints, and a model is made.
From the viewpoint of the safety of infrared illumination against the eye, illumination power 1 mW/cm² was adopted, based on the fact of infrared exposed level of workers at glass or steel manufacturers and calculation of natural light exposed in our daily life.
From another viewpoint of sensitivity and dynamic performance, silicon-vidicon tube was adopted, together with good optical system. Its sensitivity is enough under the level of safe infrared illumination. By processing TV video signal electronically, the area, vertical diameter and horizontal diameter of pupil can be measured. As the after image of this tube is reduced so much, the dynamic performance of this pupillometer is greatly improved to have the band width of about 5 Hz.
A binocular electropupillometer was also made in order to measure both pupil diameter at a time. It will be possible to apply this binocular electropupillometer to clinical use.