Choroidal Neovascular Membrane Formation in Idiopathic Intracranial Hypertension: A Scoping Review

Choroidal neovascular membrane (CNVM) formation is an uncommon but vision-threatening complication of idiopathic intracranial hypertension (IIH). While papilledema and optic neuropathy are recognized sequelae of raised intracranial pressure (ICP), the relationship between CNVM and conventional markers of disease severity remains unclear. A literature search of PubMed, Embase, and Scopus was conducted to identify published cases of CNVM in IIH. Case-level data were extracted where available, including ICP, intraocular pressure (IOP) and Frisén papilledema grade. Quantitative and narrative synthesis were performed. Forty patients (43 eyes) were identified across 26 publications. Twenty-three patients contributed extractable case-level data. CNVM occurred across a wide range of ICP values (25-40 cmH₂O) and papilledema severity (Frisén grades 1-4), without evidence of a dose-response relationship. Nearly half of patients developed CNVM at ICP ≤ 30 cmH₂O, and over a quarter had only grade 1 papilledema. CNVM in IIH arises independently of extreme ICP or papilledema, suggesting local biomechanical, vascular, or inflammatory factors contribute. Clinicians should remain vigilant for CNVM even in apparently moderate disease. These findings highlight the need for modeling and prospective studies to define predictive mechanisms and improve surveillance strategies.