BACILLARY LAYER DETACHMENT OVERLYING REDUCED CHORIOCAPILLARIS FLOW in ACUTE IDIOPATHIC MACULOPATHY

Purpose: To report new multimodal imaging features that enhance our understanding of the inflammatory and ischemic nature of acute idiopathic maculopathy (AIM) and to correlate structural and functional changes due to a reversible initial choroidal ischemia over a clinical course of 3.5 months. Methods: A 31-year-old man presented with acute central vision loss in his right eye due to coxsackievirus-associated AIM. Serial multimodal retinal imaging including confocal true color fundus photography, blue-light fundus autofluorescence (BAF), near-infrared reflectance (NIR), spectral domain optical coherence tomography and swept-source optical coherence tomography (SD-OCT + SS-OCT), and en face SS-OCT angiography (SS-OCTA) were performed over a 3.5-month follow-up. Eidon true color confocal scanner camera (Centervue, Padova, Italy) was used for color and BAF imaging. Near-infrared reflectance and SD-OCT images were obtained with the Heidelberg Spectralis OCT (HRA2 + OCT; Heidelberg Engineering, Heidelberg, Germany). For SS-OCT and en face SS-OCT and SS-OCTA images, the PLEX Elite 9,000 (Carl Zeiss Meditec, Inc, Dublin, CA) was used. Central alterations in choriocapillaris flow were analyzed with SS-OCTA using the University of Washington choriocapillaris (CC) flow deficit quantification algorithm available through the ARI Network. Flow deficit area and density values were analyzed and compared between the first and last examinations. Corresponding en face OCT imaging was used to distinguish true flow defects from artifacts secondary to shadowing. Results: In the acute stage of AIM, a bacillary layer detachment appearing as a yellow-grayish foveal elevation surrounded by a hypopigmented parafoveal ring was evident in a Bull’s eye configuration, corresponding to a hyperreflective ring upon NIR and a hyperautofluorescent ring with BAF. SD + SS-OCT showed mostly intraretinal fluid consistent with a bacillary layer detachment in conjunction with a thickened inner choroid. At presentation, SS-OCTA demonstrated a marked reduction of choriocapillaris flow signal. At 1 week, early resolution of retinal fluid was followed by restoration of the ellipsoid zone at 5 weeks, while restoration of the interdigitation zone and reduction in retinal pigment epithelium/Bruch membrane complex thickening occurred more slowly. Swept-source OCT angiography showed a gradual, but incomplete, recovery of inner choroidal flow signal at 3.5-month follow-up. Conclusion: Acutely, AIM may present with a photoreceptor splitting foveal bacillary layer detachment associated with a marked reduction in inner choroidal flow signal on SS-OCTA. Thereafter, restoration of the outer retinal layers and gradual normalization of choroidal flow signal appear to support the often-benign nature of the disease.