Although ankylosing spondylitis mainly affects the joints of the spine, it may also affect other parts of the body. One such part is the middle layer of the eye, called the uvea. Inflammation in the uvea is also called uveitis. Since your iris (the colored part of your eye) is also part of the uvea, this kind of inflammation can also be called iritis. Between 30 and 40% of people with ankylosing spondylitis will develop uveitis or iritis at some point.
Symptoms of the condition include:
- Photophobia (sensitivity to light)
- Blurry vision
- Excessive tears
The condition usually affects one eye, although it can also occur in both. Since uveitis can occur suddenly and lead to permanent vision loss, it is important to consult an eye doctor if you experience any of the above symptoms.
There are four types of uveitis. They are classified depending on which part or parts of the eye are inflamed:
- Anterior uveitis affects the inside of the front of your eye (between the cornea and the iris) and the ciliary body. It is also called iritis and is the most common type of uveitis seen in patients with ankylosing spondylitis.
- Intermediate uveitis affects the retina and blood vessels just behind the lens, as well as the gel in the center of the eye (the vitreous body).
- Posterior uveitis affects a layer on the inside of the back of your eye, either the retina or the choroid.
- Panuveitis occurs when all layers of the uvea are inflamed, from the front to the back of your eye.
Diagnosis and treatment of uveitis
Patients with ankylosing spondylitis are advised to look out for such signs as sensations of flashing lights, a red or painful eye, and blurry vision. Talk to your doctor about these signs early enough to avoid misdiagnosis and prolonged symptoms. Many people with anterior uveitis have an undiagnosed case of ankylosing spondylitis.
Your doctor will want to test and confirm the cause of your symptoms, which could be syphilis, tuberculosis, and Lyme disease. One particular test is the screening for HLA-B27, a gene that is found in 88% of ankylosing spondylitis patients. Treatment for uveitis typically includes topical or injectable corticosteroids. However, your doctor may also decide to treat you with additional medicines if the severity and frequency of recurrence of your condition demand it.