Uveitis is not a single disease but a collection of 30 to 40 different disorders that may be characterized by clinical symptoms, anatomic location, morphology, presence or absence of key anatomic findings (such as ciliary flush, keratic precipitates [KP], iris nodules, synechiae, snowballs, snowbanks, retinal vasculitis, macular edema, and optic neuropathy), and response to treatment. A thorough history and review of systems with a complete examination will typically narrow the differential diagnosis to a much more manageable number of possibilities on which the workup should be based. There is no one “uveitis workup.” The use of a “shotgun” approach to diagnostic testing is not only not cost-effective but will often lead to incorrect diagnoses and treatment based on a misunderstanding of the sensitivity, specificity, and positive and negative predictive values of a given test.

The Standardization of Uveitis Nomenclature Working Group has emphasized the clinical presentation of the disease, laterality, and the anatomic location of inflammation in the evaluation of patients with uveitis.

• The history defines the course of the disease.
  • Onset (sudden versus insidious)
  • Duration
    • Limited (<3 months) versus persistent (>3 months).
  • Course
    • Acute (sudden onset and limited duration).
    • Recurrent (flare-ups occurring >3 months after stopping therapy).
    • Chronic (persistent or flaring up <3 months after stopping therapy).
    • Note that by these criteria, the term “acute or chronic” has no meaning, and uveitis controlled with medication should be considered “suppressed” and not “in remission.”
• Laterality
  • Unilateral.
  • Unilateral/alternating (bilateral and nonsimultaneous).
  • Bilateral and simultaneous.
• Anatomic location
  • Anterior: cells limited to the anterior chamber (iritis) or with some anterior vitreous involvement (iridocyclitis)
    • Anterior chamber cells must be greater than vitreous cells.
    • Isolated anterior uveitis should NEVER be diagnosed without assessment of the retina.
  • Intermediate uveitis: Cells in the vitreous cavity (vitritis) without chorioretinal involvement; may have anterior chamber cells
    • Vitreous cells must be greater than anterior chamber cells.
  • Posterior: isolated retinitis, choroiditis, or both
    • Retinochoroiditis: primarily retinal with secondary choroidal involvement.
    • Chorioretinitis: primarily choroidal with secondary retinal involvement.
    • There may be posterior vitreous cells.
    • Optic disc edema and hyperemia may be present.
    • Neuroretinitis.
    • Retinal vasculitis
      • Venous.
      • Arterial.
      • Mixed venous/arterial.
    • Lesions in posterior uveitis should be characterized by:
      • Color
        • White lesions are usually retinal.
        • Yellow lesions are usually choroidal.
        • Pigmented lesions usually indicate long-standing disease.
      • Presence or absence of hemorrhage
      • Presence or absence of retinal vasculitis
      • Border appearance: creamy versus granular versus sharply defined
      • Pattern
        • Focal or paucifocal.
        • Multifocal.
      • Morphology
        • Placoid.
        • Punched-out.
        • Serpiginous.
        • Amoeboid.
        • Ovoid.
        • Punctate.
  • Panuveitis: concurrent anterior, intermediate, and posterior uveitis.

NOTE:

Macular edema and peripheral retinal vasculitis do not by themselves define posterior uveitis (e.g., pars planitis may have cystoid macular edema [CME], peripheral vascular sheathing and leakage, and optic disc edema but it is still an intermediate uveitis).

Hypopyon (layering of white blood cells in the anterior chamber)

• Usually white, flat-topped.
• Bloody hypopyon often suggests herpetic uveitis.
• Shifting hypopyon (changes with head position) suggests Behçet disease.

Consider different causes of or predisposing factors to uveitis (recognizing there may be substantial overlap)

• Infectious.
• Systemic inflammatory disease.
• Vascular disorders.
• Host immune status.
• Genetic.
• Drug-induced.
• Trauma.
• Environmental.

The principles of the uveitis workup should be as follows:

1. Distinguish infectious from noninfectious uveitis.
2. Distinguish purely ocular disease from uveitis associated with systemic conditions.
3. Consider masquerade syndromes (e.g., retained intraocular foreign body, tumors, chronic retinal detachment, etc.).
4. Obtain additional testing only if the results will influence the differential diagnosis, medical or surgical management, prognosis, or referral patterns.
5. Recognize that up to 40% of uveitis is undifferentiated (the term preferred to “idiopathic,” since nearly all noninfectious uveitis has no known cause) and explain this to patients.
6. Imaging, like laboratory testing, should be based on the disease and not used indiscriminately. Testing may include:
   • Optical coherence tomography (OCT).
   • Intravenous fluorescein angiography (IVFA).
   • Indocyanine green angiography (ICGA).
   • Fundus autofluorescence (FAF).
   • OCT angiography.
   • Visual field testing.
   • Electrophysiology.