A team from the University of California, San Diego, has developed a smartphone app that can accurately measure changes in pupil size as a potential method for assessing a variety of neurological conditions and disorders, including Alzheimer’s disease and ADHD. The technology relies on nearby infrared cameras, which newer smartphones use to recognize faces. The system is easy to use and can allow people to participate in home diagnostics of conditions previously diagnosed in other ways. Researchers consult with older people while designing the system to ensure that it is suitable for use by this group of patients.
Changes in the size of your pupils in response to various stimuli can reveal more about you than you think, including your cognitive state when performing complex tasks. Such information may be useful in diagnosing or monitoring neurological conditions, although this area is still relatively early for such applications. However, so far, measuring pupillary reactions has only been possible with the help of bulky and expensive hospital equipment.
This latest technological endeavor aims to make this technique accessible to everyone at home using a smartphone. “Although there is still a lot of work to be done, I am excited about the potential of using this technology to transfer neurological screening from clinical laboratory conditions to homes,” said Colin Barry, a researcher involved in the study. “We hope this opens the door to new research into the use of smartphones to detect and monitor potential health problems earlier.
Newer smartphones feature a close-up infrared camera, which is commonly used for facial recognition, along with a simple selfie camera. The researchers used both cameras to perform pupilometry based on a smartphone. The near-infrared spectrum allows the camera to more easily distinguish between the pupil and the surrounding iris with sub-millimeter levels of accuracy. This can be difficult for ordinary cameras, especially if the iris is a dark color.
Meanwhile, the app uses a simple selfie camera to measure the distance between the camera and the user’s face, which allows the system to calculate the pupil diameter in millimeters. The measurements that the system can obtain are comparable in their accuracy with those obtained with a gold standard pupillometer.
Researchers also consult with older people while designing the system to make sure it is easy to use. “For us, one of the most important factors in the development of technology is to ensure that these solutions are ultimately applicable to everyone,” Barry said. “This includes people like older people who may not be used to using smartphones.
Watch a video about the system below.
Learn in CHI Conference on Human Factors in Computing Systems, 2022: Pupilometry at home with the help of cameras for facial identification of the smartphone
through: University of California, San Diego