A hand-held device that measures the contraction of the pupils of accident victims in response to bright light will help to ensure they get the correct treatment.
When paramedics are called to an accident one of the first things they do is shine a light in the eyes of the survivors to see how their pupils react. If they contract sluggishly the person may have serious head trauma. Extra pressure in the brain caused by internal bleeding constricts the nerve that controls the pupil’s response to light.
But spotting changes in the pupil’s responsiveness is difficult, particularly when different doctors and nurses take measurements at different times.
“It is one of the only physiological parameters which still relies upon manual assessment,” says Andrew Clark, a medical technologist at Newcastle upon Tyne Hospitals NHS Trust in the UK and a member of the team that developed the new device.
To record the pupils’ reaction, doctors compare their size with a standard chart and classify the speed of the change as fast, slow or non-existent. But the technique is time-consuming and extremely subjective.