Abstract
Purpose :
Development of enhanced depth imaging (EDI) – optical coherence tomography (OCT) and OCT angiography revealed that choroidal vessels play an important role in pathology of chorioretinal diseases. However, the involvement of vortex vein (VV), which is a drainage route of blood flow of choroid, in the pathophysiology of the diseases is still unknown. The purpose of this study was to quantify the number and distribution of the VV in healthy eyes with a montage of ultra-wide field (UWF) images.
Methods :
An retrospective study was conducted in Kagoshima university hospital. UWF pseudocolor images steered center, superiorly, and inferiorly, were captured using the Optos California (Optos plc), and were converted into stereographic projection versions by Optos Advance (Optos plc) and extracted long wavelength images from those. We applied geometric transformation to register off-axis images to corresponding on-axis images, to make an UWF choroidal vessel enhanced images from the montaged images. The montaged images were projected to 3 dimensional eye model with using spherical trigonometry which can be adjusted by axial length to measure configuration of VV and optic disc. We analyzed the number of VV and the distances between optic disc and VV in quadrants (i.e. supretemporal (ST), inferotemporal (IT), supuranasal (SN) and inferonasal (IN) areas). Above factors were analyzed between the areas by Friedman test and Kruskal-Wallis test.
Results :
74 eyes of 74 subjects (male 37) were enrolled. Mean age was 36.7±10.3, mean best corrected visual acuity (logMAR) was -0.22±0.08 mean axial length was 24.9±1.11 mm and mean spherical equivalent was -3.3±2 D. The total number of VV were 8.1±1.4 and the regional number of VV were 1.8±0.66 in ST, 2.1±0.63 in IT, 2.2±0.71 in SN and 1.9±0.57 in IN. And the difference of the numbers of VV between quadrants were statistically significant. (p<0.01, Friedman test) And regional mean distances between optic disc and VV were 14.1±1.2mm in ST, 15.5±1.4mm in IT, 13.3±1.1mm in SN and 13.6±1.4 in IN, and the differences between quadrants were statistically significant. (p<0.00, Kruskal-Wallis test)
Conclusions :
The number and distribution of vortex veins are significantly different between each quadrant in healthy eyes. Because choroidal vascular structure has something to do with progression of diseases, the present study would provide an important and basic information for that
This is a 2020 ARVO Annual Meeting abstract.