title: The intensity of the light reflex on retinal arteries and veins.
abstract: The intensity profiles of the central light streak on various sized retinal vessels were measured by a computerized high quality scanning microphotometer. From the fundus photographs in 40 young men 240 arteries and 240 veins were analysed, and light streaks were found on 171 arterial and 170 venous sites. Differences in reflected intensities between arteries and veins and between small and large vessels were studied. In the whole range of vessels measured (50-200 microns) significantly higher intensities were found on arteries compared to veins (P less than 0.01). Large vessels (100-200 microns) reflected the light more intensely than small vessels (50-99 microns) (P less than 0.001). Variations in haemodynamics of flow and in physical properties of the streaming erythrocytes might account for the reflectivity differences between arteries and veins.
mesh_terms: D000328:Adult; D006801:Humans; D008027:Light; D008297:Male; D010783:Photometry; D012018:Reflex; D012161:Retinal Artery / Q000033:anatomy & histology / Q000502:physiology*; D012169:Retinal Vein / Q000033:anatomy & histology / Q000502:physiology*