Iritis (uveitis)

2.03 Iritis (uveitis)

Presentation
The patient usually complains of unilateral eye pain, blurred vision and photophobia. He may have had a pink eye for a few days, trauma during the previous day, or no overt eye problems. There may be tearing but there is ususally no discharge. Eye pain is not markedly relieved after instillation of a topical anesthetic. When you look at the junction of the cornea and conjunctiva (the corneal limbus) you will see a corcumcorneal injection which, on close inspection, is a tangle of fine ciliary vessels, visible through the white sclera. This limbal blush or ciliary flush is usually the earliest sign of iritis. A slit lamp with 10x magnification may help, but is usually evident on close inspection. As the iritis becomes more pronounced, the iris and ciliary muscles go into spasm, producing an irregular, poorly reactive, constricted pupil and a lens which will not focus. The slit lamp may demonstrate white blood cells or light reflection from a protein exudate in the clear aqueous humor of the anterior chamber (cells and flare).
What to do:



Perform a complete eye exam, including topical anesthesia if necessary; visual acuity, pupillary reflexes, funduscopy, slit lamp examination of the anterior chamber (including pinhole illumination to bring out cells and flare) and fluorescein staining to detect any corneal lesion.



Attempt to ascertain the cause of the iritis (is it generalized from a corneal insult or conjunctivitis, a late sequela of blunt trauma, infectious, or autoimmune?)



Explain to the patient the potential severity of the problem: this is no routine conjunctivitis, but a process which can develop into blindness.



Arrange for ophthalmologic consultation or followup, and, if acceptable to the consulting ophthalmologist . . .



Dilate the pupil and paralyze ciliary accommodation with 1% cyclopentolate (Cyclogyl) drops once, which will not only relieve the pain of the muscle spasm, but will keep the iris away from the lens, where meiosis and inflammation might cause adhesions (posterior synechiae). For a prolonged effect, instill 1 drop of homatropine 5% before discharge.



Suppress the inflammation with topical steroids, like 1% prednisolone (Inflamase) drops once;



Prescribe po pain medicine if needed; and



Ensure that the patient is seen the next day in followup.
What not to do:



Do not let the patient shrug off his "pink eye" and escape followup, even if he is feeling better, because of the real possibility of permanent visual impairment.



Do not overlook a penetrating foreign body as the cause of the inflammation.



Avoid dilating an eye with a shallow anterior chamber and precipitating acute angle closure glaucoma.
Discussion
Iritis (or anterior uveitis) always represents a real threat to vision which requires emergency treatment and expert followup. The inflammatory process in the anterior eye can opacify the anterior chamber, deform the iris or lens, scar them together, or extend into adjacent structures. Posterior synechiae can potentiate cataracts and glaucoma. Treatment with topical steroids can backfire if the process is caused by an infection (especially herpes keratitis); thus the slit lamp examination is especially useful.
Iritis may have no apparent cause, or be associated with ankylosing spondylitis, Reiter's syndroms, psoriatic arthritis, sarcoidosis and infections such as tuberculosis, Lyme disease and syphilis.
Sometimes an intense conjunctivitis or keratitis may produce some sympathetic limbal blush, which will resolve as the primary process resolves, and require no additional treatment. A more definite, but still mild, iritis, may resolve with cycloplegics, and not require steroids. All of these, however, mandate ophthalmologic consultation and followup.
References



Au YK, Henkind P: Pain elicited by consensual pupillary reflex: a diagnostic test for acute iritis. Lancet 1981;ii:1254-1255.