Iritis is a type of uveitis, an inflammation of the uvea, the middle portion of the eye. Iritis affects only the iris, the colored portion of the eye. The terms iritis and anterior uveitis are often used interchangeably, the American Optometric Association (AOA) states. Iritis causes pain, reddening, light sensitivity and often pupillary constriction. Many disease processes cause iritis.
Idiopathic Iritis
Iritis has no identifiable cause 50 percent of the time, the Merck Manual states. The disease is assumed to be an autoimmune response in these cases, and treatment is aimed at reducing inflammation with corticosteroid drops or injections into the eye. Aspirin and non-steroidal medications may also be given to reduce inflammation.
Trauma
Trauma to the eye is the most commonly recognized cause of iritis, according to Merck. Trauma can be caused by blunt injury to the eye, scratches or injury to the cornea, ocular burns or foreign bodies in the eye. Vision may be affected by iritis caused by trauma, and an ophthalmologist may see blood in the anterior chamber on examination, the AOA states. Intraocular pressure (IOP) may also be elevated. Corticosteroid drops or intraocular injections may be prescribed to reduce inflammation.
Connective Tissue Disorders
The genotype HLA-B27 is associated with anterior uveitis, the Indiana University School of Optometry reports. Six to 8 percent of people in the United States have this genotype. Diseases associated with this genotype include spondyloarthropathies, diseases that cause inflammation of the spine. Around 20 percent of people with anterior uveitis have spondyloarthropathies such as anklylosing spondylitis. Inflammatory bowel disease, psoriatic arthritis and reactive arthritis are also associated with anterior uveitis, along with juvenile idiopathic arthritis and systemic lupus erythematosus. People with sarcoidosis account for between 10 to 25 percent of cases of uveitis overall, Merck states. Chronic iritis can be caused by juvenile rheumatoid arthritis
Infections
Infections such as herpes simplex, Lyme disease, tuberculosis and syphilis may also cause iritis. Iritis caused by infectious disease can be treated with anti-viral of antibiotic medications. In rare cases, mumps, chlamydia, measles or flu can also cause iritis, Indiana University School of Optometry reports.
