SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF THE OPTIC DISK IN OPTIC NEUROPATHY

Purpose: To evaluate the optic nerve head microvasculature in eyes with acute and chronic optic neuropathies using swept-source optical coherence tomography angiography. Methods: In this cross-sectional, observational study, optical coherence tomography angiography images were obtained from the optic nerve heads of 21 eyes of 12 patients with optic disk edema, pseudoedema and atrophy, and 12 eyes of 6 healthy subjects using a 1,050-nm optical coherence tomography angiography (Topcon DRI OCT; Triton). Peripapillary vasculature was assessed within five horizontal slabs consisting of the nerve fiber layer (NFL), ganglion cell layer, inner nuclear layer, choroidal layer, and full-thickness retinal layer. In addition, prelaminar and laminar slabs were evaluated. Vessel density was measured within a 3.4-mm diameter circle centered on the optic disk. Results: The abnormalities of the peripapillary capillary network were most apparent in the NFL and total retinal slabs. In eyes with disk edema, an increase or decrease in the visibility of the peripapillary capillary network was observed. Eyes with optic atrophy had decreased visibility of peripapillary capillary network corresponding to the region or sector of NFL thinning. Prelaminar capillary network was dilated and tortuous in eyes with disk edema. The mean vessel density was statistically significantly lower and the mean NFL thickness was statistically significantly thinner in eyes with optic atrophy compared with normal eyes (both P < 0.001). Vessel density was significantly correlated with the peripapillary NFL thickness (P < 0.001). Conclusion: Optical coherence tomography angiography provides high-resolution, noninvasive visualization of the microvasculature of the optic nerve head and peripapillary region. Changes in the microvasculature in this region may prove useful in better characterization of optic neuropathies.