The characteristics of multimodal fundus imaging in AMN patients following COVID infection

Abstract

We investigated the features of multimodal fundus imaging in patients with both Coronavirus disease 2019 (COVID-19) and acute macular neuroretinopathy (AMN). This study included 15 patients with 29 eyes, all of whom underwent comprehensive fundus examinations and were followed for 3 months. Based on the diagnosis, patients were categorized into the AMN group and the AMN_PAMM group (AMN combined with paracentral acute middle maculopathy [PAMM]). At baseline, outer nuclear layer (ONL) thickness was not decreased in either group. However, a notable reduction in both outer retinal and full retinal thickness was observed in the AMN_PAMM group but not in the AMN group. Optical coherence tomography angiography (OCTA) demonstrated decreased vessel density (VD) in the intermediate capillary plexus (ICP) and deep capillary plexus (DCP), whereas the VD of the radial peripapillary capillary plexus (RPCP) and superficial vascular plexus (SVP) was increased in both groups. After 3 months of follow-up, ONL thickness and both outer and full retinal thickness were decreased in both groups. The VD of RPCP and SVP showed a significant decrease in the AMN_PAMM group. Visual acuity improvement was observed only in the AMN group, which may be attributed to the increase in choroid vascular index (CVI).

Keywords: Acute macular neuroretinopathy (AMN); Coronavirus disease 2019 (COVID-19); Optical coherence tomography angiography (OCTA); Paracentral acute middle maculopathy (PAMM).

Fig. 1

Fundus photographs of AMN patients. (a–d) Lesions observed in color fundus photography (CFP). (e–h) Scanning laser ophthalmoscopy (SLO) images. (i–l) Infrared fundus photography (IR) images. (m–p) Confocal scanning laser ophthalmoscopy (cSLO). images showing lesions with palm-like, wedge-shaped, trapezoidal, and petal-like characteristics. (q–s) Measurement of lesion area using cSLO.

Fig. 2

Fluorescein fundus angiography (FFA) and Indocyanine green angiography (ICGA) of patients. (a, b) FFA of patients. (a) A focal hypoperfusion in the perifoveal vascular arch region arch region (yellow arrow) in FFA in AMN patients. (b) Spot-like transparent fluorescence around the macula (red arrow) in FFA in AMN_PAMM patients. c-d. ICGA of patients. Weak fluorescence at the lesion located in macular area (black arrow) in the late stage of ICGA was observed in AMN and AMN_PAMM groups.

Fig. 3

Optical coherence tomography (OCT) finding in AMN patients. (a) At baseline, the AMN group exhibited hyperreflective signals extending from the outer boundary of the outer plexiform layer (OPL) to the ellipsoid zone (EZ) and the outer segment tips phagocytosed by the pigment epithelium (PhaZ) in the OCT. The lesion exhibited ellipsoid band and PhaZ discontinuity. (b, c) The OCT presentation of AMN at 1mo (b) and 3mo (c) of follow up. The hyperreflective bands in the the outer nuclear layer (ONL) gradually resolved. The discontinuity of the ellipsoid zone and PhaZ has been had greatly recovered.

Fig. 4

OCT findings in AMN_PAMM patients. (a) At baseline, the hyperreflectivity band extend extends from the outer plexiform layer (OPL) to ellipsoid zone and phagosomes zone (PhaZ), simultaneously appears in the inner nuclear layer (INL). The lesion exhibited discontinuity of ellipsoid band and PhaZ. b-c. The OCT presentation of AMN_PAMM at 1mo (b) and 3mo (c) of follow up. The disappearance of hyperreflective bands in both the outer nuclear layer (ONL) and INL in the macular region. The discontinuity of the ellipsoid zone and PhaZ has been had greatly recovered but not recovered completed.

Fig. 5

Vascular density (VD) in AMN and AMN_PAMM patients in OCTA. (a–c) The VD of AMN patients at baseline (a), 1mo of follow up (b), 3mo of follow up (c). (d–f) The VD of AMN_PAMM patients at baseline (d), 1mo of follow up (e), 3mo of follow up (f). Different color blocks represent different regions of the macular ETDRS grid. The O represent the macular fovea. O → A represents a circular area of 1 mm radius centered on the macula fovea (yellow block, 0-1 mm). O → B represents a circular area of 3 mm radius centered on the macula fovea (yellow block + green block, 0–3 mm). O → C represents a circular area of 6 mm radius centered on the macula fovea (yellow block + green block + brown block, 0–6 mm). A → B represents a ring area (green block, 1–3 mm). A → C represents a ring area (green block + brown block, 1–6 mm). B → C represents a ring area (brown block, 3–6 mm). We measure VD in the S, T, I, N quadrant in the 1–6 mm ring area and presented it in the macular ETDRS grid. S superior, T temporal, I inferior, N nasal, RPCP radial peripapillary capillary plexus, SVP superficial vascular plexus, ICP intermediate capillary plexus, DCP deep capillary plexus.