Birdshot Chorioretinopathy

Birdshot chorioretinopathy (pronounced: koor-ee-oh-reht-in-OHP-ah-thee) is a rare inflammatory eye disease that can lead to permanent vision changes or complete loss of sight. This long-term (chronic) condition is a severe form of posterior uveitis, a group of diseases that damage eye tissue. It damages your:

• Retina, the light-sensitive tissue at the back of your eye
• Choroid, which connects your retina to the white part of your eye (sclera)

Eye care specialists can see the hallmark signs of birdshot chorioretinopathy on a dilated eye exam. They appear as cream- and orange-colored oval spots in your deep retina and superficial (top layer) choroid. The spots resemble the pattern from birdshot, small shotgun pellets (bullets). The condition usually affects both eyes.

Birdshot chorioretinopathy is rare. Researchers believe it affects less than 1 in every 100,000 people worldwide. Other names for the condition include:

• Birdshot retinochoroidopathy
• Birdshot uveitis
• BSCR

While there’s no cure, birdshot retinochoroidopathy is a treatable disease. Early detection is essential to the success of the treatment.

Symptoms of birdshot retinochoroidopathy

BSCR symptoms can vary. It’s a disease that develops gradually, with symptoms that typically worsen over several months to years.

The first signs of birdshot chorioretinopathy are often floaters or blurred vision. BSCR doesn’t usually involve eye pain or redness, but you may also experience:

• Changing vision or vision loss
• Decreased ability to see to the side (peripheral vision) or judge depth
• High eye pressure (ocular hypertension)
• Night blindness (nyctalopia)
• Problems with color vision (color blindness) and telling certain colors apart (dyschromatopsia)
• Sensitivity to bright lights or glare (photophobia)

Some people experience unusual changes in their vision or perception. Symptoms may include:

• Ceiling fan effect (when you close your eyes, you see something like a ceiling fan or pinwheel whirring around)
• Seeing flashing or flickering lights (photopsia) or distorted shapes (metamorphopsia)
• Shimmering, blurred or hazy vision (like looking through water or dirty glass)

In severe cases, symptoms may include cataracts or glaucoma, which can cause severe vision loss even after you treat inflammation. Birdshot uveitis may also lead to issues with your central retina, including cystoid macular edema and epiretinal membranes.

It’s possible to have the early stages of this condition and not even realize it because symptoms don’t always appear right away. The earliest signs might only be low levels of inflammation that only your provider can detect through a complete eye exam.

What causes BSCR?

Researchers don’t know the exact cause of birdshot retinochoroidopathy. They suspect it may be an autoimmune disease, when your body’s immune system mistakenly attacks healthy tissues.

Most people diagnosed with BSCR inherit (receive from their biological parents) a substance (antigen) called HLA-A29 that triggers an immune response. But just because you inherit this antigen doesn’t mean you’ll get the disease. And though it’s less common, you can develop birdshot chorioretinopathy even if you don’t have HLA-A29.

Risk factors for birdshot retinochoroidopathy

Anyone can develop birdshot chorioretinopathy, though females may be slightly more likely to develop the condition. It most often affects white people between the ages of 40 and 60. It rarely affects children.

How doctors diagnose birdshot chorioretinopathy

Diagnosis of BSCR can be difficult. It’s a rare disease, and its unique spots may not be visible in the early stages of the disease.

Eye care specialists like ophthalmologists most often diagnose BSCR with an eye exam. They also use a blood test to confirm if you have the HLA-A29 antigen. They may run additional tests to diagnose and monitor the disease, including:

• Fluorescein angiography (FA): An FA is an imaging test that provides your eye care specialist with information about the blood vessels at the back of your eyes.
• Indocyanine green (ICG) angiography: Similar to an FA, an ICG angiography uses an injected green dye to evaluate the health of your choroid.
• Optical coherence tomography (OCT): An OCT scan takes pictures of your retina to look for signs of swelling or nerve damage.
• Electroretinogram: This test checks your eyesight and the functioning of your photoreceptors (rods and cones).
• Visual field test: This test evaluates your entire field of vision, including your central and peripheral vision.

Healthcare providers may use a combination of these tests to monitor you over time. Stay in touch with your provider to receive the care you need.

How is birdshot retinochoroidopathy treated?

Birdshot chorioretinopathy treatment depends on the severity of your condition and how it changes over time. The goal of treatment is to reduce swelling in your eyes and prevent or reverse vision loss.

Healthcare providers typically first recommend high doses of corticosteroids to control inflammation in your eyes. Then, they lower the dose as much as possible due to the risk of side effects. You may receive these steroids through:

• Eye drops
• Oral medicines
• An implant placed surgically in your eye (intravitreal implant)
• Injection
• IV (intravenously, through a vein)

Many people also need long-term treatment with immunosuppressants. These drugs stop your immune system from attacking your eyes and may include:

• Alkylating agents
• Antimetabolite drugs
• Biologic agents
• T-cell transduction/calcineurin inhibitors

Are there any side effects from BSCR treatment?

Long-term steroid and immunosuppressant use can cause serious side effects, including gastrointestinal or bone issues. They may also increase your risk of developing cataracts or glaucoma.

Your healthcare provider will monitor you for any side effects and prescribe other medications if you need them. If you’re taking steroids by mouth, providers will check you for bone damage (osteoporosis) and fracture risk.

Your provider may also recommend a bone density scan. You may receive medication to prevent bone loss (bisphosphonates).

When should I seek care?

Birdshot uveitis requires prompt diagnosis and treatment from an ophthalmologist. Even if your vision is fine, an eye exam can detect low levels of inflammation.

Alert your healthcare provider to any side effects of medication or any change in symptoms or vision. You may receive different medications as needed. Your healthcare provider can discuss options that work best for you.

What’s the outlook for birdshot chorioretinopathy?

The outlook for birdshot chorioretinopathy varies depending on the severity of the condition at the time of diagnosis and the effectiveness of treatment. In milder cases, vision can remain stable or improve with treatment. Some cases can remain stable even without treatment.

How can I reduce my risk of developing birdshot chorioretinopathy?

There’s no known way to prevent birdshot chorioretinopathy. In most cases, researchers believe a specific antigen (a molecule that triggers an immune response) passed down in families triggers it.

Regular eye exams can help detect early symptoms, so you can receive timely treatment if needed. Tell your healthcare provider if any family members have eye disease.