Distribution Of Blood Flow In Retrobulbar Arteries Over The Cardiac Cycle In Glaucoma Patients

Abstract

 

Purpose:

 

Altered ocular perfusion has been identified as a risk factor for the progression of primary open angle glaucoma. Therefore Color Doppler Imaging (CDI) is used in clinical and scientific practice to make these hemodynamic disturbances more objective. Results of CDI examinations are usually shown as peak systolic velocity (PSV) and end diastolic velocity (EDV) as well as derived indices like the resistivity index (RI). The distribution of blood flow velocities over the whole cardiac cycle is not reflected by these measures. The present study investigates the distribution of blood flow over the cardiac cycle in glaucoma patients and a control population.

 

Methods:

 

96 glaucoma patients and 40 healthy volunteers were enrolled in the study. Color Doppler Imaging was performed with a Siemens Elegra set–up (transducer 7.5L40 at 6.5 MHz). The ophthalmic artery (OA), the central retinal artery (CRA) and the short posterior ciliary artery (SPCA) were investigated in color doppler mode, registering PSV, EDV, RI, TAMn and the spectral waveform of blood flow velocity over the whole cardiac cycle. The distribution of blood flow over time was categorized arbitrarily in "normal" showing blood flow throughout the entire cardiac cycle, "abnormal" showing absence of end–diastolic blood flow and "intermediate" showing partial end–diastolic blood flow.

 

Results:

 

 

 

Conclusions:

 

Glaucoma patients show a predominantly abnormal blood flow in the short posterior ciliary artery, while it is normal in the large majority of the control population. If it comes to evaluate a patient’s blood flow, the spectral waveform of flow velocities throughout the entire cardiac cycle gives important information which cannot be provided by the solitary measurement of PSV or EDV.

 

Keywords: blood supply