Theoretical relations between light streak characteristics and optical properties of retinal vessels

Abstract

Abstract Due to the various surfaces of overlying structures, direct high magnification studies of retinal vessels in the living human eye is not yet possible. Our knowledge of microcirculatory mechanics of flow and morphological changes in vessel walls, is obtained by analysing information contained in reflected light from the retina. Different characteristics of the central light reflex seen on retinal vessels have, in both clinical and theoretical studies, been sought correlated to morphological wall changes in various systemic vascular diseases. In this paper we perform a theoretical study on effects of density changes and increased thickness of a vessel wall on the width and the intensity of the light streak. Assuming that the reflex originates from the intravascular column of streaming erythrocytes, we show that variations in thickness of the wall or changes in its refractive index do not influence the final image of the width of the reflex. The intensity, however, is affected by density changes in overlying structures.