Current Imaging Modalities for assessing Ocular Blood Flow in Glaucoma

Abstract

Glaucoma may be caused by an interplay of elevated intraocular pressure (IOP), vascular, genetic, anatomical, brain, and immune factors. The direct assessment of ocular hemodynam-ics offers promise for glaucoma detection, differentiation, and possibly new treatment modalities. All the methods currently in use to measure ocular blood flow have inherent limitations and measure different aspects of ocular blood flow. This review article attempts to provide detailed information on ocular perfu-sion pressure as well as an overview of the newly developed imaging technologies used to investigate ocular blood flow in glaucoma patients.How to cite this articleMohindroo C, Ichhpujani P, Kumar S. Current Imaging Modalities for assessing Ocular Blood Flow in Glaucoma. J Curr Glaucoma Pract 2016;10(3):104-112.

Evaluating ocular blood flow

“…[ 8 14 ] It is not clear, however, if the resistive index which is obtained represents the retinal vascular resistance accurately. [ 17 18 ]…”

“…[ 19 ] This noninvasive technique measures centerline blood velocity (mm/s), vessel diameter (m), and cross-sectional area, and thus total BF (L/min) can be assessed. [ 18 ]…”

“…BF can be measured with a high-level of accuracy, and LDV is one of the few methods which provides volumetric BF in units. [ 18 21 ] This technique has been used to study the effect of various antiglaucoma medications and other experimental drugs on ocular BF. [ 22 23 ] The main drawback of this method is that it may be confounded by eye motion and centerline displacement along with tear film break up, upper lid obstruction, inadequate dilation, blurred images due to media opacities; and it cannot be used to measure circulation in optic nerve head (ONH).…”

“…[ 22 23 ] The main drawback of this method is that it may be confounded by eye motion and centerline displacement along with tear film break up, upper lid obstruction, inadequate dilation, blurred images due to media opacities; and it cannot be used to measure circulation in optic nerve head (ONH). [ 18 20 24 ]…”

“…The variation pattern is dependent on the flow of blood cells in the tissue – the higher the BF velocity, the greater the rate of variation. [ 18 32 ]…”