Abstract
Purpose :
Impaired choroidal perfusion on fluorescein angiography is known to be a suggestive indicator of arteritic anterior ischemic optic neuropathy (A-AION), but not of non-arteritic anterior ischemic optic neuropathy (NA-AION). Choroidal vascularity index (CVI) is a novel noninvasive tool to assess the vascular status of the choroid. The purpose of this retrospective case control study was to compare CVI in patients with A-AION, NA-AION and control subjects.
Methods :
Macular and optic nerve head optical coherence tomography (OCT) scans of 20 patients with acute A-AION secondary to giant cell arteritis (biopsy-proven), 20 patients with acute NA-AION, and 20 control subjects were acquired with Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany). Images were binarized using the ImageJ software, and total choroid area (TCA), luminal area (LA) and stromal area (SA) were segmented. The main outcome measure was CVI, defined as the ratio of LA to TCA. A one-way ANOVA test was used to compare macular and peripapillary CVI among groups. An ANCOVA was run to determine the differences in macular and peripapillary CVI among groups after adjusting for age.
Results :
Patients with A-AION showed a significantly lower macular and peripapillary CVI compared to both patients with NA-AION (respectively, 67.17±2.35 vs 69.66±4.18, P=0.048; 63.51±3.29 vs 67.67±3.07, P<0.001) and control subjects (respectively, 67.17±2.35 vs 70.00 ± 2.95, P=0.021; 63.51±3.29 vs 68.69 ± 3.19, P=0.002) (Figure 1). Conversely, no significant difference in macular and peripapillary CVI was found between patients with NA-AION and controls (respectively, P=0.942 and P = 0.570). After adjustment for age, the difference of peripapillary CVI among groups remained statistically significant (P<0.001), while the difference in macular CVI did not (P=0.060).
Figure 1. Macular and optic nerve head OCT in a representative patient with A-AION (Part A and C), and in a representative control subject (Part B and D). Red lines represent the TCA; yellow lines represent the LA; CVI was defined as LA/TCA.
Conclusions :
Macular and peripapillary CVI are reduced in patients with A-AION. These parameters may be useful to evaluate quantitatively choroidal vascular dysfunction in A-AION, serving as a new additional diagnostic tool to distinguish A-AION from NA-AION.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.