Simulated eye test for Alzheimer's disease. Normal eye with pupil dilated (widened) after application of tropicamide eye drops. The same eye is shown in photo M108/327 with contracted pupil before the eye drops. This dilating pupil reaction is being tested to diagnose patients with Alzheimer's disease. The eyes of Alzheimer patients are highly sensitive and react (dilate) to tropicamide eye drops at low concentration, to which healthy eyes do not respond. Alzheimer's disease is usually only confirmed after postmortem. An eye test would enable early treatment of Alzheimer's disease. Tropicamide is widely used in normal eye tests.