Case Report: Longitudinal multimodal imaging and microperimetry findings in PAMM: apparent capillary rarefaction and persistent sensitivity loss across 28 months

IntroductionParacentral acute middle maculopathy (PAMM) is classically associated with retinal vascular occlusion or systemic vasculopathy. We describe an atypical presentation of isolated PAMM occurring in close temporal association with the abrupt withdrawal of systemic pharmacotherapy in the setting of isolated marked proteinuria, including a 28-month longitudinal analysis of structural and functional outcomes.Patient presentationA 37-year-old male with a history of asymptomatic proteinuria presented with acute paracentral scotomas shortly after discontinuing a short course of azilsartan and hydroxychloroquine. Multimodal imaging, including spectral-domain optical coherence tomography (SD-OCT) and OCT angiography (OCTA), revealed focal inner nuclear layer (INL) infarction and deep capillary plexus (DCP) hypoperfusion, consistent with isolated PAMM in the absence of macroscopic vascular occlusion. The patient received hyperbaric oxygen therapy (HBOT) during the acute phase; a subsequent transient improvement in localized retinal sensitivity was observed, but best-corrected visual acuity (BCVA) stabilized at 20/40. However, serial microperimetry demonstrated a transient improvement in localized macular sensitivity from 3 weeks to 9 weeks post-onset, followed by a marked secondary decline from 9 weeks to 28 months. This late-stage functional loss was topographically coupled with progressive INL and outer plexiform layer (OPL) atrophy, alongside apparent capillary rarefaction on OCTA.ConclusionsAcute hemodynamic changes following medication withdrawal, combined with a potential hypercoagulability or prothrombotic risk from proteinuria, may have contributed to the development of isolated PAMM. The long-term visual prognosis is closely associated with progressive microvascular dropout and retinal atrophy. Serial microperimetry is essential to evaluate the true functional impairment in these patients.