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

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.

• Authors: N R Graff-Radford, S C Lin, P W Brazis, J P Bolling, T J Liesegang, J A Lucas, R J Uitti, P C O'Brien
• Journal: Mayo Clinic proceedings (Mayo Clin Proc) Vol. 72 Issue 6 Pg. 495-504 (Jun 1997) ISSN: 0025-6196 [Print] England
• PMID: 9179132 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Mydriatics
• Ophthalmic Solutions
• Tropicamide

Topics

• Aged
• Aged, 80 and over
• Alzheimer Disease (diagnosis)
• Double-Blind Method
• Female
• Humans
• Male
• Middle Aged
• Mydriatics (administration & dosage)
• Ophthalmic Solutions
• Reproducibility of Results
• Tropicamide (administration & dosage)