How to Distinguish Retinal Disorders from Causes of Optic Nerve Dysfunction?

The clinical presentation of acute unilateral visual loss in a young patient can be due to a number of conditions including possible retinopathy or optic neuropathy. Although demyelinating optic neuritis is the most common unilateral optic neuropathy to present in a young adult to a neuro-ophthalmologist, the possibility of acute retinopathy should also be in the differential diagnosis especially when specific red flags for retinal disease are present. The overlapping clinical presentation of retinal and optic nerve disorders in this setting can be challenging and will affect the patients evaluation, treatment and prognosis. The main diagnostic dilemma is that a young otherwise healthy female patient who presents with acute unilateral visual loss may have idiopathic or demyelinating optic neuritis or a subtle or occult retinopathy (e.g., acute zonal occult outer retinopathy). This manuscript will describe the key differentiating clinical symptoms and signs and the specific diagnostic testing that might help h making the correct diagnosis.