University of Washington neurologist Dr. Lynn McGrath has worked with the University of Washington's Computer Sciences department to devise a smartphone app which can deliver an almost instant diagnosis. Taking inspiration from the penlight and working with a team of colleagues, the team from the two universities came up with PupilScreen - a smartphone-based diagnosis app. PupilScreen works uses the stimulation of the smartphone's flash to enable its camera to measure even the smallest changes in someone's pupil, providing results on the phone's screen in seconds. A small clinic-based pilot study earlier this year demonstrated almost perfect diagnostic accuracy for PupilScreen and there are plans for field tests in the near future.