Choroidal Vascular Changes in Arteritic and Nonarteritic Anterior Ischemic Optic Neuropathy

Purpose: To compare choroidal vascularity index (CVI) in patients with arteritic anterior ischemic optic neuropathy (A-AION), nonarteritic anterior ischemic optic neuropathy (NA-AION), and control subjects. Design: Retrospective cross-sectional study. Methods: This study was conducted at the Ophthalmology Unit of the S.Orsola-Malpighi University Hospital (Bologna, Italy). Macular and optic nerve head optical coherence tomography (OCT) scans of 20 patients with A-AION secondary to giant cell arteritis (biopsy-proven), 20 patients with NA-AION, and 20 control subjects were acquired with Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany). Images were binarized using 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. 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 = .048; 63.51 ± 3.29 vs 67.67 ± 3.07, P < .001) and control subjects (respectively, 67.17 ± 2.35 vs 70.00 ± 2.95, P = .021; 63.51 ± 3.29 vs 68.69 ± 3.19, P = .002). Conversely, no significant difference in macular and peripapillary CVI was found between patients with NA-AION and controls (respectively, P = .942 and P = .570). After adjustment for age, the difference of peripapillary CVI among groups remained statistically significant (P < .001), while the difference in macular CVI did not (P = .060). Conclusions: Macular and peripapillary CVI are reduced in patients with A-AION. These parameters may be useful to quantitatively evaluate choroidal vascular dysfunction in A-AION, serving as a new additional diagnostic tool to distinguish A-AION from NA-AION.