Simple device for measuring pupil size, first of its kind, designed by Dr Alan Gilston, made for the First World Congress on Intensive Care, London 1974, by Medical and Industrial Equipment Limited

Eye pupil size was measured in patients during cardio-respiratory resuscitation and coma assessment by this simple device. This is the first of its kind made for the First World Congress on Intensive Care, held in London in 1974. The plastic ruler has holes representing pupil dilation at various stages. Change in pupil size can be triggered involuntarily by exposure to bright light and this can be used as a guide to brain activity. Such changes to the pupil can also be caused by strokes, brain tumours, head injuries and the use of illegal drugs. This simple low-tech device is a quick reference tool for physicians in critical care situations.

Dr Alan Gilston was the senior Consultant Anaesthetist at the National Heart Hospital, London. He established the Intensive Care Society in 1974. He initiated the First World Congress on Intensive and Critical Care Medicine later that year.