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Mentions: Tropicamide solution of 0.005% concentration was prepared just before each test. Before the test, the images of the eyes were taken as rest pupil size, and then one drop of 0.005% tropicamide was administered to one eye of each subject, while one drop of normal saline solution was administered to another eye. The images of the eyes were taken every 5 minutes for 60 minutes after drug administration. The images were stored in computer memory for future analysis (Figure 1). Pupil and iris sizes were measured, using Photoshop software (Figure 2). The ratio of pupil size to iris size before drug administration was expressed as 100%. The graph of percent changes in pupil size versus time after drug administration was plotted.
An image processing technique for diagnosis of Alzheimer's disease
Bottom Line: Every 5 minutes for 60 minutes, image of the eye's shape were taken, and the diameter of the pupils was measured.ROC analysis showed that after 35 minutes the sensitivity and specificity of the test were 100%.Based on our results, we concluded that this recording system might be an appropriate and reliable tool for pupil response diagnosis test of Alzheimer's disease.
Affiliation: Razi Institute for Drug Research, Department of Pharmacology, Iran University of Medical Sciences, Tehran, Iran.
Background: Patients with Alzheimer's disease (AD) reportedly exhibit hypersensitivity to much diluted tropicamide solution (0.005%), a M4 muscarinic receptor antagonist. Therefore intraocular application of 0.005% tropicamide may be useful for screening dementia. The aim of this study was to simplify the pupil response test by using a new image analyzing system, which consists of a cheap, simple, and easy to use web-camera and a computer.
Methods: Intraocular tropicamide of 0.005% concentration was administered in 3 groups: Alzheimer's disease patients (n = 8, average age = 76 ± 5), non-Alzheimer's disease elderly (n = 6, average age = 65 ± 7), and young subjects (n = 8, average age = 28 ± 5). Every 5 minutes for 60 minutes, image of the eye's shape were taken, and the diameter of the pupils was measured.
Results: The results showed that differences in pupil dilation rate between Alzheimer's disease and non-Alzheimer's disease subjects were statistically significant. ROC analysis showed that after 35 minutes the sensitivity and specificity of the test were 100%.
Conclusions: Based on our results, we concluded that this recording system might be an appropriate and reliable tool for pupil response diagnosis test of Alzheimer's disease.