Abstract
Purpose :
Non-arteritic anterior ischemic optic neuropathy (NAION) is considered an ischemic disorder of the optic nerve head, but current methods to measure blood flow using fluorescein and OCT angiography do not adequately quantify blood flow in the optic nerve head and adjacent peripapillary choroid. We sought to quantify the dynamics of blood flow longitudinally using laser speckle flowgraphy (LSFG), which provides a non-invasive quantification of blood flow simultaneously in the retinal, optic nerve head and choroidal vascular beds during the cardiac cycle.
Methods :
A case-control study of 48 patients with NAION and 15 control subjects > 50 years of age were tested by LSFG. Eleven patients were tested during the acute stage. Six of the patients were tested during both the acute and atrophic stages to assess change over time. Blood pressure, intra-ocular pressure, OCT and visual field testing were performed. Ocular perfusion pressure was used to calculate vascular resistance for each region of interest defined after the 4 second video was recorded.
Results :
A highly significant correlation was found between each of the 8 sectors of the optic nerve rim tissue and corresponding adjacent peripapillary choroid in the NAION patients (coefficient R=0.727; p=0.0001) and in the normal subjects (R=0.683; p=0.0001). Most importantly, there was a proportional decrease in both optic nerve rim blood flow and corresponding peripapillary choroid over time.
Conclusions :
The high correlations between LSFG blood flow in the optic nerve rim tissue and corresponding peripapillary choroid further supports that both the prelaminar optic nerve vascular bed and peripapillary choroid are supplied by distal branches of the same parent posterior ciliary arteries. The proportional reduction in blood flow in the optic nerve head tissue and corresponding sectors of the peripapillary choroid over time supports that ischemia to both of these vascular beds occurs in NAION.
This is a 2020 ARVO Annual Meeting abstract.