Birdshot Chorioretinopathy

What is birdshot chorioretinopathy?

Birdshot chorioretinopathy, birdshot uveitis or BSCR is an inflammatory eye disease affecting both eyes. It is a rare eye condition that causes inflammation of the uvea (a part of eye made up of the iris, ciliary, body and choroid). This eye condition is difficult to treat and is a severe form of uveitis. Uveitis comes in different forms:

• Inflammation of the iris is called anterior uveitis
• Inflammation of the choroid is called posterior uveitis
• Inflammation of ciliary body is called intermediate uveitis
• Inflammation of all the areas of the uvea is called diffuse uveitis

Birdshot uveitis is form of posterior uveitis and it affects the choroid and retina. The retina is light-sensitive tissue at the back of your eye. The choroid supplies the retina with oxygen and nutrients through blood vessels. It also accounts for 85% of the total blood flow in the eye. This eye condition is usually identified through small oval cream-coloured yellow spots on the retina and choroid.

Disruption in the blood flow leads to this rare eye condition. According to the Cleveland Clinic, this disease affects less than 1 in every 100,000 people.

Birdshot chorioretinopathy symptoms

This disease often starts with eye floaters and blurred vision. Eye floaters are various shaped particles within your eye that you see when you look at something bright, such as looking at the sky or a white paper. The main symptoms of this condition are:

• Floaters
• Reduced vision or vision loss
• Night blindness (nyctalopia)
• Problem with colour vision (colour blindness)
• Flashes of light
• Blurry vision, such as looking through a glass
• Soreness/pain (not very common)
• Loss of peripheral vision
• Photophobia – sensitivity to bright lights or glare

Some people might also experience a ceiling fan effect (seeing a whirring around pattern like a windmill or fan when you close your eyes).

Who gets birdshot uveitis?

Although anyone can develop this eye condition, it predominantly affects people in middle age, 45-50 years old. It can also affect people who are much younger.

What causes birdshot chorioretinopathy

This eye condition is an autoimmune disease. An autoimmune disease is when the body’s immune system starts attacking the good cells by mistake. The exact cause is unknown; however, it is said to be connected with a substance called HLA-A29; it is an antigen substance that triggers an immune response. The Cleaveland Clinic explains that more than 90% of the people diagnosed with this disease inherits HLA-A29, showing the part played by this substance in this eye condition. However, you don’t necessarily need to have this antigen to get this disease. You can also have this antigen and yet not get the disease.

How is birdshot chorioretinopathy diagnosed?

As this disease is quite rare, initially people don’t take the symptoms too seriously. The above-mentioned symptoms are not specific to birdshot uveitis and are broad ranged; they can point to various eye diseases. The diagnosis of this condition is difficult, and its unique spots may not be visible in the early stage of this disease. Cream-coloured oval spots may be visible at the back of the eye during an eye examination, and this may indicate birdshot chorioretinopathy. Your optometrist will then refer you for further tests. You will be put through a series of tests, including a blood test to best detect this disease and rule out other possibilities.

Is there a cure to birdshot chorioretinopathy?

No, there’s no cure for this disease. You can either inherit it or develop it at a later stage of your life. However, this eye condition can be controlled, or symptoms can be reduced with timely diagnosis and treatment.

Birdshot chorioretinopathy treatment

For most people, the treatment starts with doses of steroids to control the inflammation of choroid and retina. Your doctor will reduce the doses with time. Steroids can be consumed in different forms, such as eye drops, oral medicines, injection or implants. Other people might be prescribed with immunosuppressants to control the attack of their immune system on their eyes. However, long-term treatment with steroids and immunosuppressants can come with side effects (can be manageable, depending on the person), such as bone problems, digestion-related issues etc. Theres is no set rule of treatment for this disease so, its recommended to monitor your symptoms and work with your doctor.

You will be advised to go for regular eye exams, including visual field tests, optical coherence tomography (OCT) scans, and colour blindness tests.

What kind of ongoing monitoring is important for birdshot uveitis?

Keep a close watch on your symptoms as well as the frequency/pattern of your symptoms. You should even look out for any side effects that you might be experiencing and anything unusual in your body, even a headache should be accounted for. Regardless, you should go for regular eye tests as it will help in detecting any forthcoming eye-related problems.