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Emily C. Wright, Sabin Dang, Emily Cole, Carlos E. Mendoza, Thomas Hedges, Laurel Vuong; Optical Coherence Tomography Angiography in Ischemic Optic Neuropathy. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5073.
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© ARVO (1962-2015); The Authors (2016-present)
Non-arteritic anterior ischemic optic neuropathy (nAION) is thought to be a consequence of hypoperfusion of branches of the short posterior ciliary arteries. Optical coherence tomography angiography (OCTA) is a technology that is allowing us to better visualize vascular pathology in ocular diseases. In this study we utilize OCTA to qualitatively depict the changes in the peripapillary vasculature in patients with nAION.
Patients with a prior or new diagnosis of nAION were recruited. The following were acquired for both eyes in each patient: OCTA of the peripapillary vasculature using the Optovue RTVue XR Avanti AngioVue®; structural OCT images of the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCC) using a Zeiss Cirrus 5000; Humphrey Visual Fields (HVF). OCTA images were qualitatively graded for peripapillary retinal capillary and peripapillary choriocapillaris perfusion by a masked reader who reported whether each quadrant had OCTA changes consistent with low flow. The findings were then compared to HVF findings and RNFL and GCC measurements to assess for correlation.
Five patients were recruited, two of whom had bilateral nAION. Among the 7 eyes with nAION, OCTA of the optic nerve head revealed radial peripapillary capillary dropout that correlate with HVF deficits as well as RNFL and GCC thinning on structural OCT. Additionally, in five of the seven eyes, OCTA of the peripapillary choriocapillaris demonstrated ischemic changes which correlated with HVF deficits as well as RNFL/GCC structural OCT findings. In the remaining two eyes, angiography of the choriocapillaris was unreliable due to overlying optic nerve edema and motion artifact. In patients with unilateral nAION, there was an appreciable difference in the flow signal in the peripapillary choriocapillaris and retinal capillaries between the two eyes, with the affected eye demonstrating a relative decreased flow signal and vascular density.
Our findings suggest that flow to both the peripapillary choriocapillaris and the radial peripapillary retinal capillaries are affected in nAION eyes. This has been difficult to demonstrate with traditional angiography. With the depth encoded angiogram provided by OCTA we are able to visualize segmental hypoperfusion of the these regions. To our knowledge, this is the first report to describe these findings. We plan to further this work through quantification of areas of low flow.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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