Paracentral Acute Middle Maculopathy in a Young-Onset Case Revealing Undiagnosed Hypertension.

Paracentral acute middle maculopathy (PAMM) is a rare retinal ischemic disorder resulting from ischemia of the intermediate and deep retinal capillary plexus (DCP), causing secondary injury to the inner nuclear layer (INL). It typically occurs in older adults with vascular risk factors but can rarely present in young patients without prior systemic disease. A 37-year-old man presented with sudden visual impairment in the right eye. Fundus photography and fluorescein angiography were unremarkable; however, Humphrey visual field testing revealed a paracentral scotoma. Optical coherence tomography (OCT) revealed a band-like hyperreflective lesion in the INL, and OCT angiography (OCTA) revealed a localized DCP dropout. Systemic evaluation identified previously undiagnosed hypertension (213/136 mmHg), and laboratory tests excluded diabetes, dyslipidemia, and hypercoagulable disorders. Therefore, oral antihypertensive therapy was initiated. Three months later, blood pressure normalized (127/86 mmHg), the intensity and thickness of the OCT lesion decreased, and visual symptoms improved, although DCP dropout persisted on OCTA. This case demonstrates that young-onset PAMM may be the first sign of systemic hypertension. Elevated blood pressure can induce retinal microvascular ischemia, and timely management can lead to partial functional recovery despite persistent structural changes. Comprehensive systemic evaluation is recommended in young patients with PAMM to prevent further ischemic damage and improve outcomes.