Acute zonal occult outer retinopathy

A rare retinal disease affecting vision

Acute zonal occult outer retinopathy (AZOOR) is a rare retinal disorder characterized by sudden onset of visual field loss, often accompanied by photopsia, or the perception of flashing lights. The condition primarily affects young to middle-aged adults and is more prevalent in females. AZOOR is part of a group of retinal diseases known as the "AZOOR complex," which also includes acute macular neuroretinopathy, acute idiopathic blind spot enlargement, and multifocal choroiditis.

Pathophysiology

The exact cause of AZOOR is not well understood, but it is believed to involve an inflammatory process affecting the outer retina, particularly the photoreceptor layer. The disease may be associated with viral infections or autoimmune responses, although no specific pathogen has been consistently identified. The condition is characterized by the loss of photoreceptors in one or more zones of the retina, leading to the characteristic visual field defects.

Clinical Presentation

Patients with AZOOR typically present with sudden onset of visual disturbances, which may include:

• Loss of visual field in one or both eyes
• Photopsia (flashing lights)
• Decreased visual acuity
• Metamorphopsia (distorted vision)

The visual field loss is often described as a "zonal" defect, affecting specific areas of the visual field while sparing others. The condition can be unilateral or bilateral, and the severity of symptoms can vary widely among patients.

Diagnosis

The diagnosis of AZOOR is primarily clinical, based on the patient's symptoms and the characteristic appearance of the retina on examination. Diagnostic tests that may be used to support the diagnosis include:

• Visual field tests to map the extent of visual field loss
• Optical coherence tomography (OCT) to assess the integrity of the retinal layers
• Electroretinography (ERG) to evaluate retinal function, often showing reduced or absent responses in affected areas
• Fluorescein angiography to rule out other retinal vascular conditions

Management

There is no specific treatment for AZOOR, and management is primarily supportive. Some patients may experience spontaneous improvement in their symptoms, while others may have persistent visual field defects. Treatment options that have been explored include:

• Corticosteroids to reduce inflammation
• Immunosuppressive therapy in cases suspected to have an autoimmune component
• Antiviral medications if a viral etiology is suspected

Prognosis

The prognosis for patients with AZOOR varies. Some individuals may experience partial or complete recovery of vision, while others may have permanent visual field defects. The condition can be stable or progressive, and long-term follow-up is often necessary to monitor changes in vision.

Related pages

• Retinal disease
• Photoreceptor cell
• Visual field
• Autoimmune disease