What Is Acute Zonal Occult Outer Retinopathy?

Acute zonal occult outer retinopathy (AZOOR) is a rare eye condition that affects the retina, the layer of tissue located at the back of the eyeball. AZOOR often starts with symptoms like sudden flashing lights, blind spots, or blurred vision, and eventually leads to vision loss.

There's no cure for AZOOR, but treatments such as corticosteroids and immunosuppressant drugs can potentially help recover vision loss in some people. This article provides an overview on AZOOR, its symptoms, causes, and treatment.

Symptoms

Eye conditions that affect the retina usually result in changes to your vision. People with AZOOR may notice symptoms such as:

• Sudden onset of a blind spot (a small gap in your visual field)
• Blurred vision
• Flashing or shimmering lights (photopsias)

Typically, just one eye is affected, but sometimes AZOOR-related vision changes can be experienced in both eyes.

Causes

Experts don’t know exactly what causes AZOOR, but some possible theories are:

• Viral theory: Initial research from the 1990s suggests that certain viruses may play a role in the development of AZOOR. Anecdotally, patients have reported having a viral infection (like the flu) before experiencing AZOOR symptoms.
• Autoimmune theory: Other research suggests that AZOOR is the result of autoimmune disease. Studies have shown a link between patients with systemic autoimmune diseases (like Hashimoto’s disease, hypothyroidism, and multiple sclerosis) developing AZOOR.

While the exact underlying cause hasn’t been determined, researchers have narrowed down some more clues based on who typically develops the condition. Anyone can be affected, but AZOOR is most often diagnosed in women, with an average onset age of 36.7 years old.

In addition, it may be linked to nearsightedness, and does not appear to be genetic.

Diagnosis

AZOOR can be difficult to diagnose. This is because when an eye specialist, such as an optometrist or an ophthalmologist, examines your eye, the retina may appear fairly normal. Your specialist will likely have to use additional tests to make a diagnosis, such as:

• Electroretinogram: This test measures the electrical activity of the retina in response to a light.
• Fundus autofluorescence: This type of imaging can provide information about the health and function of the retina by recording fluorescence (emission of light) that occurs in the structure of the eyes.
• Optical coherence tomography: This imaging scan can determine if there is degeneration of the outer layer of the retina.
• Fluorescein angiography: By injecting a safe dye into the bloodstream, specialists can view the blood vessels in the back of the eye more clearly.
• Visual field testing: Standard vision testing can help identify any blind spots or vision loss due to an abnormality in the retina.

Treatment

While there’s no specific treatment to cure AZOOR, healthcare professionals may try a few different types of medications to help recover vision loss, including:

• Systemic corticosteroids: Medications like prednisone that help decrease inflammation in the body are commonly used in AZOOR treatment. In some patients, corticosteroids can help reverse vision loss.
• Immunosuppressive therapies: These medications also help lower inflammation in the body without the steroid component. Studies show they have mixed results in AZOOR patients but are sometimes used after patients taper off corticosteroids.
• Antiviral treatments: This class of drugs is typically used to shorten the severity and duration of a viral infection. Some studies have shown an improvement of AZOOR vision loss in patients after using antiviral medications like valacyclovir.
  

Prognosis

As with other eye conditions, each case of AZOOR is different, so the prognosis can vary.

Some AZOOR patients may experience varying amounts of vision recovery after treatment, while others may continue to experience vision loss even after treatment is complete. Still others may show vision improvement at first, but then experience a recurrence of AZOOR and more vision loss later.

Summary

Acute zonal occult outer retinopathy (AZOOR) is a rare eye condition that can result in vision loss. Symptoms include flashes of light, blind spots, and blurred vision. AZOOR is usually treated with corticosteroid, immunosuppressant, or antiviral drugs, and for some people, vision loss can improve. The exact cause of AZOOR is unknown, but research suggests that certain viruses or the body's immune system response may play a role.

A Word From Verywell

You may or may not have significant vision loss with AZOOR, but dealing with any eye condition that has the potential to cause vision loss can be scary. While there are currently no treatments that will cure this condition for everyone, research is underway to learn more. If you or someone you know is affected by vision loss, support is available through organizations such as American Council of the Blind.