Correlation of Optic Disc Morphology Using Hrt Imaging and Ocular Blood Flow Parameters in Patients With Primary Open Angle Glaucoma

Abstract

Purpose: : Several lines of evidence indicate that beside intraocular pressure altered ocular blood flow regulation may contribute to the pathogenesis of glaucoma. Little information is, however, available about the relationship between morphological changes of the optic disc and different ocular blood flow parameters. In the present cross-sectional study vascular parameters were correlated against parameters of structural damage of the optic nerve head as assessed with the Heidelberg retina tomography (HRT II).

Methods: : 103 patients with primary open angle glaucoma, documented visual field defects and optic disc morphology changes were included in this cross-sectional study. Choroidal and optic nerve head blood flow was assessed using Laser Doppler Flowmetry. Retinal blood velocities were measured with Laser Doppler Velocimetry and retinal vessel diameters were measured with a Retinal Vessel Analyzer. Retinal blood flow was calculated based on retinal vessel diameters and retinal blood velocities. To evaluate optic nerve head morphology HRT II imaging was performed.

Results: : Optic nerve head blood flow was negatively correlated with cup/disc area ratio (r = -0.29; p = 0.022) and positively correlated with RNFL cross sectional area (r = 0.28; p = 0.030). Retinal blood flow velocity was negatively associated with cup/disc area ratio (r = -0.33; p = 0.005).

Conclusions: : Reduced blood flow in the optic nerve head was associated with increasing degree of visual field defect and glaucoma-induced morphological changes of the optic nerve head. In contrast to retinal vessel diameters, optic nerve head blood flow is closely associated to the disease process in glaucoma.

Clinical Trial: : www.clinicaltrials.gov NCT00803504

Keywords: optic disc