An improved apparatus of infrared videopupillography for monitoring pupil size

Abstract

The intraocular pressure (IOP) can diagnose or track glaucoma generally because it is one of the physiology parameters that are associated with glaucoma. But IOP is not easy and consistent when measured under different measure conditions. Besides, diabetes is associated with diabetic autonomic neuropathy (DAN). Pupil size response might provide an indirect means about neuronal pathways, so the abnormal pupil size may relate with DAN. Hence an infrared videopupillography is needed for tracking glaucoma and exploring the relation between pupil size and DAN. Our previous research proposed infrared videopupillography to monitor the pupil size of different light stimulus in dark room. And this portable infrared videopupillography contains a camera, a beam splitter, the visible-light LEDs for stimulating the eyes, and the infrared LEDs for lighting the eyes. It can be mounted on any eyeglass frame. But it can modulate only two dimensions, and we cannot zoom in/out the eyes. Moreover, the eye diameter curves were not smooth but jagged because of the light spots, lone eyelashes, and blink. Therefore, we redesign the optical path of our device to have three dimension modulation. Then we can zoom in the eye to increase the eye resolution and to avoid the LED light spots. The light spot could be solved by defining the distance between IR LED and CCD. This device has smaller volume and less cost then our previous videopupillography. We hope this new infrared videopupillography proposed in this paper can achieve early detection of autonomic neuropathy in the future.