A 34-year-old male is referred to the eye clinic for a painful red right eye. He says the eye became red and painful overnight three days ago and has persisted since. He also complains of severe photophobia and blurred vision. There are no symptoms of floaters, flashes, or visual field loss. His past ocular and medical history are unremarkable and there is no recent history of illness.

On exam, best-corrected visual acuity is 6/12 and 6/6 in the right and left eyes, respectively. Intraocular pressures are 18 and 14. Anterior segment exam is shown below: there is diffuse conjunctival injection with ciliary flush. There are also keratic precipitates (KPs), 3+ cell in the anterior chamber, and a 2 mm hypopyon. Posterior segment exam is normal, with no evidence of vitritis.

Anterior uveitis is defined as inflammation of the iris alone (iritis), anterior part of the ciliary body (anterior cyclitis), or both structures (iridocyclitis).¹ It is the most common cause of uveitis overall, accounting for about 90% of cases.² The annual incidence is approximately 8 cases per 100,000 per year.² There are numerous causes of anterior uveitis, with the condition being more common in HLA-B27 positive individuals. Generally it is more common and less severe than posterior uveitis, especially with prompt recognition and early treatment.