LAUSR

The purpose of this study was to evaluate whether the complexity of corneal pulse (CP) signal differentiates primary open-angle glaucoma (POAG) patients from healthy subjects. The study sample consisted of 28 POAG patients and a control, age-matched group of 30 subjects. After standard ophthalmic examination, the CP signal of a randomly selected eye of each participant was measured using a non-contact ultrasonic micro-displacement measurement technology. After preprocessing, the complexity of CP signals was estimated using the refined composite multiscale fuzzy entropy (RCMFE) up to a scale factor No. 50. The average values of RCMFE were computed from three repeated measurements of the CP signals for each participant and each scale factor. Complexity of the CP signal in glaucomatous eyes was higher than that observed in healthy ones. Also, RCMFE of the CP signal was found to statistically significantly differentiate between the two groups for scales in the range from 26 to 43. For these scales, the one for which the lowestp-value (t-test;p= 0.017) was obtained when comparing RCMFE between the two groups was selected as the optimal scale. Next, a receiver operating characteristic analysis for the optimal scale showed that the proposed approach of calculating the multiscale entropy of the CP signal has some potential to discriminate between POAG patients and healthy controls (sensitivity, specificity, and accuracy of 0.643, 0.700, and 0.672, respectively). In conclusion, RCMFE, as a complexity measure, may be considered an auxiliary indicator supporting glaucoma diagnostics.