Optical coherence tomography angiography in acute unilateral nonarteritic anterior ischemic optic neuropathy: A comparison with the fellow eye and with eyes with papilledema

Abstract

Purpose:The purpose of this study is to detect the optic nerve head (ONH) and peripapillary perfusion in eyes with acute nonarteritic anterior ischemic optic neuropathy (NAION) compared to the fellow normal eyes using optical coherence tomography angiography (OCTA) and to compare with nonischemic disc edema (papilledema).Methods:Retrospective analysis of patients with unilateral NAION who underwent OCTA was performed. All patients underwent comprehensive ocular examination including visual field testing. ONH was imaged using 6 mm × 6 mm scan by Topcon DRI Triton® OCT system. Vascularity loss was analyzed using ImageJ software in diseased eyes in comparison to normal fellow eyes and eyes with papilledema.Results:Twenty-one patients (15 males, 6 females) with unilateral NAION and 9 patients (18 eyes) with papilledema were included in the study. In eyes with NAION, two distinct patterns of loss of vasculature were noted – (a) diffuse loss of microvasculature cuff and vascular network around the optic disc in all the patients (100%) and (b) additional area of sectoral loss of vasculature extending from the disc in 12 of the 21 eyes (57.14%). All 18 eyes with papilledema showed loss of the microvasculature cuff; however, none showed the focal pattern of vascular defect. The mean area of the peripapillary vascular zone in eyes with NAION was significantly lesser than that in normals. Of the 12 eyes with NAION with focal loss of vasculature, 11 correlated with visual field defects (91.6%).Conclusion:Deficient peripapillary choroidal vasculature is present in NAION and has a different pattern than in nonischemic disc edema and can cause corresponding visual field deficits.

Optical Coherence Tomography Angiography in Neurodegenerative Disorders

“…The differential diagnosis between with arteritic anterior ischemic optic neuropathy (A-AION) and NA-AION has important clinical implications because the former may lead to profound bilateral loss of vision that may be prevented with high-dose corticosteroid treatment [ 101 ]. In patients with NA-AION, OCT-A studies revealed perfusion deficit at the level of radial peripapillary capillaries with preserved choriocapillaris perfusion [ 102 , 103 , 104 ]. On the other hand, two studies evaluating the vascular changes in patients with A-AION reported choriocapillaris perfusion deficit on OCT-A [ 105 , 106 ].…”

Comment on: Optical coherence tomography angiography in acute unilateral nonarteritic anterior ischemic optic neuropathy: A comparison with the fellow eye and with eyes with papilledema

“…Gandhi et al . [1] seem erroneously to imply that their study is the first to show that. They seem to reinvent the wheel.…”

“…I was interested to read the article by Gandhi et al .,[1] who reported the presence of peripapillary choroidal filling defect in acute nonarteritic anterior ischemic optic neuropathy (NA-AION) seen on optical coherence tomography angiography. In 1974, I described, for the first time, the clinical entity of “anterior ischemic optic neuropathy.”[2] Since then, I have exhaustively investigated, both experimentally and clinically, the pathogenesis and various aspect of NA-AION, including doing fluorescein fundus angiographic (FFA) studies in over a thousand patients with acute NA-AION.…”

“…I have described my findings extensively in numerous of publications for more than 40 years and recently summarized those in my book entitled “Ischemic Optic Neuropathies.”[3] In the light of those studies, I have the following comments about the article by Gandhi et al . [1]…”

“…Gandhi et al . [1] have used confusing terminology in their article. The peripapillary region has two vascular beds: anteriorly, the retinal vascular bed, and posteriorly, the choroidal vascular bed.…”