RESPONSE OF THE PUPIL TO TROPICAMIDE IS NOT A RELIABLE TEST FOR ALZHEIMER-DISEASE

Objective: To confirm the putative hypersensitivity of the pupil to a weak mydriatic in persons with Alzheimer dementia. Design: Twenty pati ents with Alzheimer dementia and 20 control subjects were examined. Au tomated binocular infrared pupillography was performed in the dark aft er instillation of 0.01% tropicamide or placebo. Ocular penetration of eye drops was assessed simultaneously using 2% fluorescein sodium as a tracer. Setting: Rochester, Minn. Subjects: Twenty patients and 20 c ognitively normal central subjects from the Alzheimer's Disease Patien t Registry of the Mayo Clinic, Rochester, Minn. Main Outcome Measure: Percent change in the diameter of the pupil following topical ocular i nstillation of a diluted concentration of the mydriatic drug tropicami de and penetration of topically applied fluorescein into the aqueous h umor. Results: No statistically significant difference was found betwe en patients with Alzheimer disease and control subjects in either the mydriatic response of the pupil or in the rate of penetration of topic ally applied fluorescein. Conclusion: No evidence of pupillary hyperse nsitivity to an anticholinergic mydriatic drug was found in patients w ith Alzheimer disease or any evidence that this putative hypersensitiv ity could be used as an early, simple diagnostic test for Alzheimer di sease.