Does AS Cause Vision or Eye Changes?
A form of inflammatory arthritis, ankylosing spondylitis (AS) is a chronic, progressive disorder that primarily affects the spine, although joints in the arms and legs can also be affected. The chronic inflammation can also cause extra-articular (beyond the joint) manifestations, including inflammation in the eyes, called uveitis.1
What is uveitis and does ankylosing spondylitis cause uveitis?
Uveitis (pronounced you-vee-eye-tes) is inflammation in the eye that occurs in the middle layer of the eye (the uvea). Uveitis is the most common extra-articular manifestation of AS, occurring in about 25 to 30 percent of people with the disease.1 The front (anterior) uvea includes the iris (the colored part of the eyes), and inflammation in the anterior uvea may also be called iritis.2,3 It is estimated that 90% uveitis associated with AS is anterior uveitis, with only 10% being posterior (the back of the eye) uveitis.4
Uveitis seems to occur more frequently in people with AS who have the HLA-B27 marker. It is also more common in those with peripheral AS.2
What is the role of HLA-B27 in uveitis?
HLA-B27 is a genetic marker that has been identified as playing a role in the cause of AS, although not everyone with AS has the HLA-B27 mutation and some people with the HLA-B27 mutation do not develop AS. The exact role of HLA-B27 in uveitis is unknown, although uveitis occurs more often in people with AS with the genetic marker. Researchers have speculated that protein that is produced by the HLA-B27 mutation may be directly or indirectly involved in triggering an autoimmune response. The protein has some similarities with certain bacteria, and a previous infection by one of these bacteria could trigger antibodies that then mistakenly attack the HLA-B27 protein. Other theories suggest that the immune system may react specifically to the HLA-B27 protein, or that the HLA-B27 protein may directly alter the immune system response.2
People with AS with the HLA-B27 mutation tend to develop uveitis at a younger age, have a longer duration of eye disease, and have more recurrences of uveitis. Those with the HLA-B27 marker also tend to have more severe uveitis, which may result in a higher risk of complications and the need for more aggressive treatment.2
What are the symptoms of uveitis?
Uveitis usually occurs in just one eye. However, it may occur in both eyes. While some people may have chronic eye symptoms, most cases of uveitis in people with AS are acute and symptoms occur suddenly. Uveitis can also be is recurrent, with the condition returning after treatment. Because uveitis can be a serious condition, anyone experiencing sudden eye symptoms should consult an ophthalmologist (eye specialist). Symptoms include eye pain, redness, blurry vision, sensitivity to light (photophobia), and increased tear production.1,3
How do doctors treat uveitis?
Uveitis can damage the person's vision if not properly treated. The prognosis is dependent on the ability to control the inflammation in the eye. The goals of treating uveitis are to reduce the inflammation, relieve the symptoms, and preserve or restore the individual's vision.2