Background Evaluation of pupillary light reflex (PLR) is an important neurological test with a variety of clinical applications. Obstacles such as severe soft tissue damage or hyphema may obstruct the visual access to the pupil, thus rendering direct PLR observation difficult or impossible. Multipurpose ultrasonic systems, however, can overcome this problem. Methods Using ultrasound imaging, a coronal view of the iris and pupil allowed visualization of PLR upon contralateral stimulation with a penlight. The technique was tested in ten healthy volunteers and a trauma case study. Results Satisfactory visualization of the iris was achieved in all subjects, in an average time of 1 min 10 s. Temporal parameters of pupillary constriction, oscillations (hippos) and relaxation could also be measured on M-mode displays. Conclusions Real-time coronal imaging of the iris using multipurpose ultrasound imaging is found to be a practical, fast and recordable method that can be used for evaluating PLR.