Pattern visual evoked potentials and their relation to the peripapillary and retrobulbar blood flow in glaucoma

Abstract

To examine the relationship between the development of bioelectric response of retinal cell elements to pattern stimulus and the ocular blood flow. Electrophysiological studies, including pattern-reversal visual evoked potentials (VEP) with large 1 degree (1°) and small 0.25° checks, Color Doppler imaging (CDI) of the retrobulbar vessels, and OCT Angiography in the area of the optic disc and peripapillary retina were performed in 48 patients with initial primary open-angle glaucoma (POAG), 47 patients with advanced POAG, and 42 control subjects. Authors also studied the correlations between VEP values and the parameters used in CDI and OCT-A examination. The most noticeable differences between the study groups were the amplitudes of P100 pattern VEP values for small and large patterns and the OCT-A parameters: Whole-image Disc Vessel Density (widVD), Peripapillary Vessel Density (pVD), Peripapillary Vessel Density Inferior Temporalis (pVD IT). In initial glaucoma, a strong correlation was observed between the amplitude of P100 pattern VEP 1° and pVD IT (r=0.75; p<0.0001); the blood flow rates in ophthalmic artery, central retinal artery, central retinal vein and short posterior ciliary arteries were below normal, while the blood flow in these vessels had statistically reliable correlation with the amplitude of P100 pattern VEP (p<0.05). No correlation was found in patients with advanced stages of glaucoma. Pattern VEP is an informative method of glaucoma diagnostics which accuracy can be enhanced by combining it with OCT-A blood flow examination.