Coincident PAMM and AMN and Insights Into a Common Pathophysiology

To analyze imaging characteristics and the clinical course of patients demonstrating coincident lesions of paracentral acute middle maculopathy (PAMM) and acute macular neuroretinopathy (AMN) in the same eye.

Retrospective, observational case series.

Lesions from patients presenting with coincident PAMM and AMN in the same eye were evaluated with multimodal imaging including optical coherence tomography (OCT). The association with ocular and systemic findings was also investigated.

Fifteen subjects (17 eyes) were included in the study. The mean age was 44.4 ± 15.3 years and the follow-up period ranged from 1 to 32 weeks (mean, 11.9 ± 11.4 weeks). The mean visual acuity was 0.8 ± 0.6 logarithm of minimal angle of resolution (Snellen equivalent 20/126) at baseline and 0.3 ± 0.4 logarithm of minimal angle of resolution (Snellen equivalent 20/40) at the last follow-up. PAMM and AMN lesions occurred in the setting of Purtscher's retinopathy (4 eyes, 3 patients), retinal vein occlusion (7 eyes, 7 patients), central retinal artery occlusion (1 eye, 1 patient), and idiopathic retinal vasculitis (1 eye, 1 patient). In 4 eyes (3 patients), an association with other ocular disorders was not identified as evaluated with multimodal imaging. Of the total cohort, 11 eyes (64.7%) showed extension of the AMN hyperreflective bands in Henle's fiber layer with a Z-shaped morphology on OCT B-scan.

The presence of coincident PAMM and AMN suggests a common pathophysiologic etiology. This may be the result of retinal vein impairment and hypoperfusion at the level of the deep retinal capillary plexus possibly leading to injury to the Müller glia or photoreceptors in Henle's fiber layer.