Potential Diagnostic System for Alzheimer's Disease

Development of a Long Time Pupil Area Measurement System Using Pupil+Iris Area Compensating Method

Abstract

A potential link between Alzheimer's disease and hypersensitive pupil dilation has been reported. Patients diagnosed with probable Alzheimer's disease by standard clinical criteria exhibited a marked hypersensitivity in the pupil dilation response to a cholinergic antagonist, tropicamide, placed in their eyes. We have devised a system to measure pupil area stably and intermittently for 60 minutes. This system could potentially be used for Alzheimer's disease diagnosis using this neurobiological test. The system consists of a probe with a high resolution infrared CCD camera and a real time pupil area analysis system using computer imaging processing. Averaging the pupil area during times of eye open, pupillary waves and blinking, and using the constant pupil+iris area to compensate for eye image size variation allows accurate measurement.