Correlation between ocular pulse amplitude measured by dynamic contour tonometer and colour doppler flow imaging of the arteric retrobulbar vessels

Abstract

Introduction. An altered perfusion of the optic nerve head has been proposed as a pathogenic factor in glaucoma. Objective. The aim of this study was to evaluate the correlation between ocular pulse amplitude (OPA), measured by Dynamic contour tonometer (DCT) and colour Doppler imaging (CDI) of the arteric retro- bulbar vessels. Methods. Twenty patients older than 50 years were examined, and divided into two equal groups. The first group comprised of patients with normal tension glaucoma treated with topical antiglaucomatous therapy, and the second group included patients with ocular hypertension and glaucoma suspicious without any antiglaucomatous therapy. Ocular pulse amplitude (OPA) was measured with DCT. CDI was also performed. We measured haemodynamic parameters of the internal carotid artery (ICA), ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary arteries (PCA). Peak systolic (PSV), end- diastolic (EDV) velocities were measured, and resistance index (RI) and pulsatility index (PI) were calculated. Results Correlation with OPA showed indirect servitude in the RI of the ICA, RI and PI of the CRA, in the first group; and in the PSV and EDV of the ICA, in the RI and PI of the OA, EDV and RI of the CRA, and RI of the PCA, in the second group Conclusion. Increase of OPA was mostly followed by the increase of the parameters (PSV, EDV, RI, and PI) of the arteric retrobulbar vessels in the first group; in the second group, increase of OPA was in almost 50% of parameters followed by their decrease.

Keywords

• ocular pulse amplitude
• dynamic contour tonometer
• colour Doppler imaging