Some pathogenetic mechanisms of visual disorders formation in patients with cerebrovascular disease

Abstract

Background. Changes occurring in the body during cerebrovascular disease (CD) inevitably influence the structural and functional state of the visual system, thereby determining the development of clinically advanced or latent ischemic damage to the visual organ, which represents a combined or comorbid form of the disease.

The aim of this study was to assess regional cerebral blood flow and the degree of retinal and choroidal microcirculation impairment and their relationship with the structural and functional characteristics of the visual system in patients with CD and in combination with chronic ischemic optic neuropathy (CION).

Materials and methods. The study involved 85 people (48% men, 52% women) aged 60 to 75 years. Based on the examination results, 3 groups of patients were formed: 1 – patients with CD and CION (n = 34); 2 – patients with CD and the absence of morpho functional changes in the visual analyzer (n = 30); 3 – individuals of comparable age without characteristic neuroimaging changes in the brain, no structural and functional disorders of the vision organ (n = 21).

Results. In patients with "isolated" CD, compared with the controls, the following were revealed: increased tone of large cerebral vessels; decreased density of parafoveal capillaries in the foveolar avascular zone; total perfusion density of the superficial vascular plexus; capillary density of the lower half of the deep vascular plexus of the para foveolar region; vessel density in the lower half of the radial peripapillary plexus. In patients with CD and CION, compared with the controls, the following were revealed: increased tone of medium and small cerebral arteries; decreased systolic blood flow to the brain during one cardiac cycle in the carotid and vertebrobasilar basins; increased dicrotic index in the carotid basins; decreased venous outflow; decreased perfusion density of the foveolar avascular zone of the retina. In these patients, compared to both the control and the group of individuals with "isolated" CD, the blood flow velocity in the carotid artery system is reduced, the thickness of the intima-media complex and the degree of stenosis at the bifurcations of the common carotid arteries are increased; the area and perimeter of the foveolar avascular zone; diffuse rarefaction of the capillary density in all zones; decreased density of the capillary bed of the superficial vascular plexus, especially in the upper half of the para foveolar zone; the density of the entire microcirculatory bed.

Conclusion. Indicators of structural and functional changes in the visual system, cerebral circulation, and ocular microcirculation in patients with CD combined with CION are interrelated.