This disclosure relates to systems, media, and methods for quantifying and monitoring visual acuity, motor skill, and cognitive ability of a user through measuring user activities while the user responds to prompts on an electronic device. Disclosed embodiments may receive image data from a user-facing camera, motion data from a sensor device attached to the user, location data from a touchscreen, and time data measuring a user's response times. Disclosed embodiments may provide graphical user interfaces to which the user responds and calculate health metrics based on characteristics of the user's response. Disclosed embodiments may calculate visual acuity, motor skill, and cognitive ability metrics based on data measured while the user responds to the graphical user interfaces. Disclosed embodiments may include comparing the metrics to respective baseline values and providing an alert when the metrics deviate from threshold values indicating a change in user health.
