Acute anterior uveitis, also known as iritis, is the inflammation of the anterior or posterior chamber and iris. It is not a true ocular emergency, and with proper treatment and follow-up, it has a good prognosis.
Uveitis is subdivided into anterior and posterior components.
Uveitis may involve inflammation of any of these components and also can include other surrounding tissues such as the optic nerve, sclera, and retina. Uveitis is often idiopathic, but it may be triggered by genetic, immune, traumatic, or infectious mechanisms.
Symptoms of uveitis depend on the type (anterior, posterior, or intermediate) and duration (acute or chronic).
Most cases of iritis are idiopathic, while 20% are due to blunt force trauma. Nontraumatic iritis often is associated with systemic diseases including juvenile rheumatoid arthritis, ulcerative colitis, Reiter syndrome, sarcoidosis, and ankylosing spondylitis. Infectious causes also include tuberculosis, herpes simplex, toxoplasmosis, varicella-zoster virus, and syphilis.
Anterior uveitis is the most common form of uveitis (occurring every 12 per 100 000 cases). It predominantly occurs in young and middle-aged people. In western countries, 50% to 70% of all uveitis cases are classified as anterior uveitis.
Eye pain is thought to be due to irritation of the ciliary nerves and ciliary muscle spasm. Photophobia is caused by irritation of the trigeminal nerve from the ciliary spasm. Increased permeability of blood vessels in anterior chamber allows proteinaceous transudate ("flare") and WBCs ("cells"), the characteristic 'flare and cells' seen with the slit lamp.
The majority of cases of uveitis are idiopathic, however, a systemic cause must always be considered.
Important causes that should suggest uveitis as the underlying cause of ocular pain include a history of any of the following:
Given the wide range of causes for iritis, a thorough ophthalmic, medical, and family history including recent trauma, infection, or medication is important for proper evaluation. A complete review of the system also will be important as complaints of systemic symptoms can alert the health care provider to the need for further workup. The patient will complain of unilateral pain which is bilateral with systemic disease. Other common findings may include conjunctival injection, consensual photophobia, and decreased vision.
Physical exams should include a penlight exam, visual acuity, and intraocular pressure readings. Typical history and "cell and flare" (WBCs and/or proteinaceous fluid in the anterior chamber) seen on slit lamp examination is diagnostic for anterior uveitis.
If systemic involvement or infectious disease is suspected to be the underlying cause, further laboratory tests or imaging may be required.
Chest radiography may be considered if sarcoidosis or tuberculosis as the underlying cause of uveitis is a consideration.
Laboratory workup is usually not necessary. In mild unilateral nongranulomatous uveitis with trauma or no evidence of systemic disease laboratory studies are unlikely to be helpful.
If there is the presence of bilateral granulomatous or recurrent uveitis, a workup is indicated. Tests to consider include:
Treatment is primarily aimed at reducing inflammation and pain and preventing complications. First-line treatment involves topical cycloplegics (dilate the pupil, prevent ciliary body and pupillary spasm) and topical steroids (decrease inflammation). The patient should be referred to an ophthalmologist within 24 to 48 hours.
Block nerve impulses to the ciliary muscles and pupillary sphincter to decrease photophobia and pain.
Cyclopentolate 0.5% to 2%
Corticosteroids decrease inflammation. Treatment should only be initiated after consultation with an ophthalmologist.
Tumor Necrosis Factor Blockers
Infliximab or adalimumab may be used as second-line treatment for patients with vision-threatening chronic uveitis caused by seronegative spondyloarthropathy.
The differential diagnoses includes:
The prognosis is good with appropriate treatment.
If untreated, complications can include decreased visual acuity and/or blindness, glaucoma, cataracts, and irregular pupil.