Birdshot chorioretinopathy is a rare inflammatory eye disease that can gradually steal your vision if left untreated. Named for the scattered pattern of cream-colored spots it leaves across the back of the eye (resembling the spread of birdshot pellets from a shotgun), this chronic condition primarily affects white adults between the ages of 40 and 60. It strikes roughly 0.035 people per 100,000 each year, making it one of the least common forms of eye inflammation.
How Birdshot Affects Your Eyes
Birdshot chorioretinopathy is a severe form of posterior uveitis, a category of diseases that damage tissue at the back of the eye. The condition is autoimmune in nature: your immune system produces inflammatory cells that attack the choroid (the blood vessel layer beneath the retina) and the retinal pigment layer that supports it. These immune cells trigger inflammation that disrupts the barrier between the blood supply and the retina, letting fluid and inflammatory signals leak into areas they shouldn’t reach.
Over time, this ongoing inflammation produces the disease’s signature finding: dozens of oval or round, yellowish spots scattered across both eyes. The spots represent areas where the choroid has been damaged. Left unchecked, the inflammation can also cause fluid buildup in the central retina (macular edema), which is one of the most common complications. In a long-term study of 142 patients, more than 60% needed multiple rounds of treatment to resolve this swelling, and recurrence was frequent.
Early Symptoms to Recognize
The first signs are usually floaters or mildly blurred vision. Because these symptoms are so common and often harmless, birdshot is easy to dismiss in its earliest stages. Over weeks to months, you may notice:
- Increased floaters in one or both eyes
- Blurred or hazy vision that doesn’t improve with new glasses
- Difficulty seeing in dim light or adapting to darkness
- Loss of peripheral vision, which can progress if inflammation continues
- Color vision changes, where colors appear washed out
The disease almost always affects both eyes, though one may be worse than the other initially. Central vision (the sharpness you use for reading) can often be preserved long term with treatment, but peripheral vision tends to narrow gradually, especially in people who only receive short-term care.
The Genetic Link: HLA-A29
Nearly 96% of people diagnosed with birdshot carry a specific genetic marker called HLA-A29. This is a protein on the surface of your cells that helps your immune system distinguish your own tissue from foreign invaders. In people with HLA-A29, something causes the immune system to misidentify the retinal pigment cells as a threat and mount an attack against them.
Carrying HLA-A29 doesn’t mean you’ll develop birdshot. About 7% of white populations carry this marker, while the disease itself is extraordinarily rare. Some additional trigger, still not fully understood, appears to be necessary for the disease to activate. Testing for HLA-A29 is, however, a key part of diagnosis. A negative result makes birdshot very unlikely.
How Birdshot Is Diagnosed
Diagnosis relies on a combination of what your eye doctor sees during an exam, genetic testing, and specialized imaging. The characteristic cream-colored or yellow-orange spots on the choroid are the hallmark finding, but in early disease these spots can be subtle or absent entirely.
A type of imaging called indocyanine green angiography (ICG) is particularly valuable because it can reveal the choroidal spots as dark patches before they become visible on a standard eye exam. This makes ICG one of the most important tools for catching birdshot early. Fluorescein angiography, a related test, helps detect leaking blood vessels in the retina. Optical coherence tomography (OCT), which creates cross-sectional images of your retina, can identify macular edema and show disruption of the retinal layers. About 64% of patients show specific changes in the choroid on enhanced OCT imaging.
The formal diagnostic criteria, established by an international group called the Standardization of Uveitis Nomenclature, require either the classic spot pattern in both eyes or a positive HLA-A29 test combined with characteristic findings on ICG angiography.
Treatment and Long-Term Outlook
Steroids are typically the first treatment to bring active inflammation under control quickly, but they are not enough on their own. Corticosteroids alone are considered ineffective at preventing relapses, and the side effects of long-term high-dose steroids (weight gain, bone thinning, elevated blood sugar) make them a poor standalone strategy. In one study, prolonged steroid therapy controlled inflammation in only about half of patients.
For this reason, most specialists add a second medication early in the course of treatment to suppress the immune system more precisely while allowing steroid doses to be tapered down, often to less than 5 mg per day. When these first-line options aren’t enough, biologic medications that target specific immune pathways have shown effectiveness in stubborn cases. One biologic in particular showed the lowest rate of macular edema recurrence (around 10%) compared to other treatments in a large long-term study.
The prognosis depends heavily on how consistently you stay on treatment. Research tracking patients over years found that those who received long-term immune-suppressing therapy maintained stable peripheral visual fields, while those who only received short-term treatment experienced measurable worsening over time. Central visual acuity, the kind of vision you rely on for reading and recognizing faces, can generally be preserved long term with sustained care. The takeaway is clear: birdshot is a marathon, not a sprint, and ongoing monitoring with regular imaging is essential to catch flare-ups before they cause permanent damage.