Some implementations disclosed herein provide systems, methods (200) and devices (10) that use a
retinal imaging technique to assess a user's eye (45)
accommodation (i.e., focusing) during use of an electronic device (10), e.g., in real-time. One or more light sources (322a-d, 1022a-d) produce one or more illuminated spots (320, 420, 520, 620) on the
retina that are detectable via a sensor (324, 1024). The size and shape of the spots (320, 420, 520, 620) depend on the eye
accommodation / focusing, and thus are used to identify
accommodation / focusing changes or measure the eye's accommodation / focusing. Eye accommodation can be determined in real-time while a user is viewing, interacting with, or otherwise experiencing
electronic content via the electronic device.