Abstract
Purpose:
Arteriovenous (AV) crossing sites can be used to identify and evaluate arteriosclerosis. These sites are generally assessed using two-dimensional fundus photographs. Here, we evaluate three-dimensional morphological features of AV crossing sites using optical coherence tomography (OCT) images and examine associations between OCT and fundus photograph findings.
Methods:
Eighty-one eyes from 81 subjects (mean age = 70.1 ± 9.1 years) with no retinal diseases had one retinal arcade AV crossing site examined with sequential thin sectioning Spectralis OCT. Fundus photographs were also taken and the crossing phenomena (normal, concealment, tapering) were evaluated.
Results:
Crossing phenomena were observed on fundus photographs in 60 of 81 AV crossing sites (concealment in 22 sites, tapering in 38 sites). Sequential thin sectioning OCT clearly revealed morphological features of the retinal vasculature. Major retinal arteries and veins ran straight within the inner retinal layers in all eyes examined. At AV crossing sites, veins abruptly deepened to pass under retinal arteries. Mean retinal arterial diameter was unchanged at crossing sites, but mean venous diameter was reduced by 13.4% in normal eyes and by 25.6% in eyes with crossing phenomena. Venous narrowing was more severe in eyes with crossing phenomena (P < 0.001). Interestingly, At the AV crossing site, venous lumen was narrowed, but not flattened. Additionally, in eyes with crossing phenomena, mean arterial diameter was significantly larger (P < 0.001) than that in normal eyes, and veins passed deeper through the retina (P = 0.007).
Conclusions:
Sequential thin sectioning OCT clearly shows the three-dimensional architecture of the retinal crossing sites. Crossing phenomena at AV crossing sites observed on fundus photographs may be associated with a larger arterial diameter and venous narrowing.
Keywords: 550 imaging/image analysis: clinical •
688 retina •
419 anatomy