Purchase this article with an account.
Monika Ewa Danielewska, Patrycja Krzyzanowska-Berkowska, D Robert Iskander, Biomedical Signal Processing Group; Assessing the incidence of ocular dicrotism in healthy and glaucomatous eyes. Invest. Ophthalmol. Vis. Sci. 2014;55(13):5877.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To ascertain whether the incidence of ocular dicrotic pulse (ODP), recently observed in elderly subjects (Danielewska, OVS 2014; 91(1)), shows increased levels in glaucomatous eyes and those of glaucoma suspects.
A study including 261 subjects aged 47 to 78 (mean±SD, 63.0±7.8 y.o.) was performed at the Glaucoma Clinic of the Department of Ophthalmology, Wroclaw Medical University. All subjects underwent general medical history review and ophthalmologic examination. The screened patients were classified in three groups: diagnosed primary open angle glaucoma (POAG: 70 patients; 60.0±6.4 y.o.), primary angle-closure glaucoma (PACG: 61 patients; 65.0±7.6 y.o.) and glaucoma suspects with glaucomatous optic disc appearance (GODA: 60 patients; 66.6±9.7 y.o.). The control group (CG) consisted of 70 healthy subjects (61.2±5.3 y.o.). A new non-contact ultrasonic method was used to measure corneal indentation pulse (CIP). Synchronically, to monitor cardiovascular activity, measurements of electrocardiogram (ECG) signal and blood pulse wave were taken. The acquired signals were numerically processed in a custom written program in Matlab. Due to signal nonstationarity Dynamic Time Warping algorithm was applied to average signal shapes for one heart cycle. A double peak-shaped character of CIP signal was assessed based on the relative relationship between the peaks in the CIP waveform. The ODP waveform was declared when the valley between any two peaks in an averaged CIP signal was below a level corresponding to 0.707 of the lower of the two peaks (−3dB criterion).
The double-peak-shape of the CIP signal (ODP) was observed in the majority of examined subjects. Mean percentage of ODP occurrence (MPO) was 66%, 82%, 65% and 77% for the POAG, PACG, GODA and CG, respectively. Additionally, subjects in each group were divided into two subgroups: ≤63 and >63 y.o. The percentage of ODP change with age was POAG (ΔMPO=29%), PACG (ΔMPO=30%), GODA (ΔMPO=−3%) and CG (ΔMPO=10%).
Increased incidence of ocular dicrotic pulse was observed in older subjects (>63 y.o.) and was most evident in PACG group. Greater ocular rigidity or biomechanical changes of eye tissue in glaucomatous eyes might be an additional factor to age responsible for this phenomenon.
This PDF is available to Subscribers Only