Tropicamide eyedrops cannot be used for reliable diagnosis of Alzheimer's disease

Neill R. Graff-Radford, Siong Chi Lin, Paul W. Brazis, James P. Bulling, Thomas J. Liesegang, John A. Lucas, Ryan J. Uitti, Peter C. O'Brien

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Abstract

Objective: To evaluate the mydriatic effect of tropicamide eyedrops as a diagnostic test for Alzheimer's disease. Material and Methods: In a double- blind, placebo-controlled study, we assessed pupillary responses in 22 normal control subjects, 23 patients with probable Alzheimer's disease, 4 patients with isolated memory difficulty, and 6 patients with non-Alzheimer's dementia. Three separate studies were performed, the second and third on a subset of the original group. With use of infrared binocular pupillography, after 5 minutes of dark adaptation, we averaged pupil size during a 1-minute interval for baseline determinations. We then instilled 0.01% tropicamide into one eye. In the first two studies, we averaged pupil size for a 1- minute period at 5-minute intervals for 30 minutes, followed by a pupil light reflex test. In the third study, we measured pupil size every 5 minutes for 45 minutes and omitted the light reflex test. Results: No significant difference was noted in pupil dilatation between normal subjects and patients with Alzheimer's disease and between patients with non-Alzheimer's dementias and the Alzheimer's disease group in all three studies. Furthermore, on reperformance of the test in the same patients, more than 50% changed from a group above or below 13% pupil dilatation (a cutoff reported tO distinguish Alzheimer's disease from normal control subjects) to the opposite group. Conclusion: Results of this study indicate that pupil measurement after instillation of tropicamide cannot be used as a reliable diagnostic test for Alzheimer's disease. Moreover, test-retest reliability with use of dilute tropicamide eyedrops is questionable.

Original languageEnglish (US)
Pages (from-to)495-504
Number of pages10
JournalMayo Clinic proceedings
Volume72
Issue number6
DOIs
StatePublished - Jan 1 1997

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Cite this

Graff-Radford, N. R., Lin, S. C., Brazis, P. W., Bulling, J. P., Liesegang, T. J., Lucas, J. A., Uitti, R. J., & O'Brien, P. C. (1997). Tropicamide eyedrops cannot be used for reliable diagnosis of Alzheimer's disease. Mayo Clinic proceedings, 72(6), 495-504. https://doi.org/10.4065/72.6.495