PupilScreen is revolutionizing neurological care by establishing the first vital sign for the brain. Using an AI-powered smartphone application, PupilScreen enables clinicians to evaluate pupil size and light reactivity as biomarkers for brain health. As a next-generation Software-as-a-Medical Device (SaMD), it offers a simple, easy-to-use solution requiring no special training, setting a new standard in pupillometry for monitoring neurological status and trends.