Optic Nerve Angle in Idiopathic Intracranial Hypertension

Area of Science:

• Neuro-ophthalmology
• Radiology
• Intracranial Pressure Disorders

Background:

• Idiopathic intracranial hypertension (IIH) is characterized by elevated intracranial pressure (ICP).
• Optic nerve tortuosity, quantified by the optic nerve angle (ONA), may reflect ICP changes.
• The relationship between ONA, ICP, and visual function in IIH requires further investigation.

Purpose of the Study:

• To investigate the correlation between the optic nerve angle (ONA) and cerebrospinal fluid (CSF) opening pressure.
• To determine if ONA correlates with visual function in patients with idiopathic intracranial hypertension (IIH).
• To assess the utility of ONA in identifying patients with raised ICP.

Main Methods:

• Retrospective study comparing IIH patients and controls with brain MRI and CSF opening pressure measurements.
• Neuro-ophthalmologic assessments including visual acuity and Humphrey Visual Field (HVF) were performed.
• Sagittal ONA was measured on MRI, and papilledema was graded using the Frisén scale.

Main Results:

• Patients with IIH exhibited a significantly smaller ONA compared to controls.
• No significant correlation was found between ONA and CSF opening pressure in the IIH group.
• ONA did not correlate with visual acuity, HVF mean deviation, or papilledema severity (Frisén grade).

Conclusions:

• The optic nerve angle (ONA) is significantly reduced in patients with idiopathic intracranial hypertension (IIH).
• ONA does not correlate with cerebrospinal fluid opening pressure, papilledema severity, or visual function.
• ONA may aid in identifying patients with elevated ICP but not necessarily those with poor visual prognosis.