Peripapillary Halos in Inflammatory Optic Neuritis of Birdshot Chorioretinopathy

Abstract

Purpose : Peripapillary halos (PPHs) are peripapillary changes observed in normal eyes and eyes with different disorders. Recognizing the microstructure and mechanism of development of these halos will help clinicians understand the different associated retinal and optic nerve head (ONH) pathologies. We report the in-vivo histologic characterization of PPH in birdshot chorioretinopathy (BSCR) patients.

Methods : Prospective series of 6 eyes of 3 patients with convalescent BSCR. In addition, to complete ophthalmic examinations, patients underwent ONH imaging using swept-source optical coherence tomography (SS-OCT), color and red-free photography, and fundus autofluorescence (FAF).

Results : In SS-OCT scans across the area of PPH, we observed thinning and interruption of retinal pigment epithelium-Bruch’s membrane (RPE-BM) complex. These halos are a circumferential form of α- zone RPE-associated crescentic PPH, unlike the PPHs observed with myopia and normal aging that are mainly associated with β-zone atrophy. We hypothesize that circumferential PPH (versus crescentic PPA) is the result of swelling of the ONH associated with BSCR papillitis, due to stretching, thinning, and tearing of the retinal layers attached to and surrounding the border tissue of Elschnig (considered to be the optic disc border). After resolution of ONH edema, the retinal layers no longer are fully attached to the disc border and have an atrophic circumferential ring around the ONH (a halo) that is PPH.

Conclusions : PPH in BSCR patients might be used as a clinical marker for prior inflammatory optic neuropathy.

This is a 2021 ARVO Annual Meeting abstract.

 

Right ONH of one of the patients. (A) ONH color photo with a PPH. (B) FAF of ONH shows hypo-autofluorescent lesions indicating thinning and interruption of RPE. (C) Red-free image of the ONH showing the extent of PPH. (D, E) SS-OCT showing thinning and focal loss of RPE with hyper-reflectivity of the underlying choroid in the peripapillary region with white arrowheads marking the extent of PPH"

 

Left ONH of one of the patients. (A) ONH color photo with a PPH. (B) FAF of ONH shows hypo-autofluorescent lesions indicating thinning and interruption of RPE. (C) Red-free image of the ONH showing the extent of PPH. (D, E) SS-OCT showing thinning and focal loss of RPE with hyper-reflectivity of the underlying choroid in the peripapillary region with white arrowheads marking the extent of PPH"