Abstract
Purpose :
OCT angiography (OCT-A) is a new technology allowing the imaging of retinal microvascular flow without the injection of an intravenous dye. This new tool is mainly used for the visualization of the retinal and choroidal vascularization of the macular area. Some studies have also shown some modifications in peripapillary vascularization in glaucoma patients. But, so far, there is no information related to potential alterations in ischemic optic nerve neuropathy. Even if the most significant contribution to the vascularization of the optic nerve comes from the choroidal blood flow through the posterior ciliary artery, the peripapillary capillaries also contribute to the vascularization of the prelaminar portion of the optic nerve.
The goal of this study is to describe the peripapillary microvasculature in nonarteritic anterior ischemic optic neuropathy (NAION) with optical coherence tomography angiography (OCT-A).
Methods :
Observational study of 10 patients at the acute phase of NAION. OCT-A was performed using a 3mm x 3mm square centered on the optic disc (Cirrus prototype modified to perform OCT Angiography, Carl Zeiss Meditec, Dublin, CA). A qualitative comparison was made with healthy fellow eye of each patient. All patients, except 2, have had a fluorescein angiography (HRA2, Heidelberg, Allemagne) and a visual field examination (Octopus 101®, Haag-Streit, USA).
Results :
In the affected eyes, OCT-A imaging demonstrated clear modifications in the radial peripapillary network. In all these eyes, a focal disappearance of the superficial capillary radial pattern was at least demonstrated and found to be twisted and irregular. In 7 eyes, there is also a lack of vascularization in some focal areas, appearing as dark zones. No correlation was found between vascular alteration topography shown in the OCT-A neither with the early phase of the fluorescein angiography nor with visual field defects.
Conclusions :
OCT-A is a safe and quick imaging tool able to demonstrate a reshaping of the peripapillary capillary network during the acute phase of NOIAN. These modifications are likely related to a decrease of the prelaminar optic nerve blood flow during the acute phase of NOIAN. The lack of anatomo-clinical correlation with visual field defects suggests that the latter are mainly due to posterior ciliary artery blood flow disturbance.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.