What is Uveitis?
Uveitis is inflammation of the uvea—the middle vascular layer of the eye composed of the iris, ciliary body, and choroid—that causes eye redness, pain, photophobia, floaters, and blurred vision, and represents a rare but sight-threatening condition that can lead to permanent vision loss if untreated 1.
Disease Classification and Epidemiology
Uveitis is classified anatomically based on which structures are inflamed:
- Anterior uveitis (41-60% of cases): Affects the iris and ciliary body
- Intermediate uveitis (9-15%): Involves the pars plana and peripheral retina
- Posterior uveitis (17-23%): Affects the choroid and/or retina
- Panuveitis (7-32%): Involves all uveal layers 1
The condition predominantly affects working-age adults between 20-50 years old 1. Histologically, all forms are characterized by lymphocytic infiltration, predominantly CD4+ T cells 2.
Etiology
Noninfectious uveitis is far more common in high-income countries, representing the majority of cases 3. The disease can be categorized as:
- Idiopathic: 27-51% of cases in the US and Europe
- Associated with systemic disease: 37-49% (including axial spondyloarthritis, Behçet's disease, sarcoidosis)
- Infectious: 11-21% in high-income countries (toxoplasmosis, herpes, tuberculosis, HIV) but up to 50% in low- and middle-income countries 1
Genetic factors (HLA-B27), environmental factors (air pollution), and regional infection rates influence incidence and prevalence 1.
Clinical Significance and Complications
Uveitis is a potentially blinding disease that causes significant morbidity in the working-age population 3, 4. If left untreated, complications include:
- Cystoid macular edema (most common cause of central vision loss)
- Cataracts
- Glaucoma
- Retinal detachment
- Optic nerve damage
- Permanent vision loss 1, 4
Patients rank not meeting vision requirements for driving, developing glaucoma, and needing eye surgery as more concerning than systemic side effects from treatment 3, emphasizing the profound impact on quality of life.
Key Clinical Pitfall
The chronic nature of uveitis requires ongoing treatment and monitoring, as recurrence is common and indicates disease severity 3. The specific therapeutic approach varies significantly by underlying etiology—for example, Behçet's disease requires different management than sarcoidosis 3.