Anterior Ischemic Optic Neuropathy

The Sonographic Assessment of the Optic Nerve Sheath in Giant Cell Arteritis (SONIC-GCA) study will evaluate the performance of the optic nerve sheath diameter (ONSD), measured via ultrasound, to diagnose and monitor GCA. SONIC-GCA builds upon our previous pilot studies and will answer the following questions: 1. What is the performance of ONSD to identify patients with new-onset, active GCA? 2. Is ONSD useful for monitoring GCA relapses during follow-up? 3. What is the intra- and interobserver reliability of ONSD measurements? 4. Does ONSD differ between patients with and without GCA-related retinal findings?

This observational study aims to enhance the description of the different ways Giant Cell Arteritis (GCA) affects vision. The latest technology and knowledge are used to improve how we diagnose and predict patient outcomes. GCA is the most frequent vasculitis, an inflammation of vessels, in older adults. It involves large and medium-sized arteries and causes ischemic alterations such as stroke and blindness, through damage of extracranial arteries. The primary objective is to compare the frequency of the various ocular findings between the main alterations of arteritic and non-arteritic aetiology, such as Arteritic Anterior Ischemic Optic Neuropathy (A-AION) Vs. Non-Arteritic Anterior Ischemic Optic Neuropathy (NA-AION) or Central Retinal Artery Occlusion (CRAO) from GCA Vs. from other causes, through a comprehensive clinical and instrumental evaluation.