Fluorescein Angiography in the Diagnostic Workup for Uveitis
Yes, fluorescein angiography (FA) is an essential component of the diagnostic workup for uveitis, particularly for evaluating posterior segment involvement, detecting occult retinal vasculitis, and assessing macular edema.
Role of Fluorescein Angiography in Uveitis Evaluation
Fluorescein angiography serves several critical functions in uveitis diagnosis:
- Detects occult retinal vasculitis that may not be visible on clinical examination alone 1
- Evaluates the extent of macular edema, which is a common complication of uveitis 2
- Identifies areas of capillary dropout, leakage, and vascular abnormalities that characterize posterior segment inflammation 3
- Distinguishes between different types of uveitis based on characteristic angiographic patterns
- Helps determine disease activity even when the eye appears clinically quiescent 4
Diagnostic Algorithm for Uveitis
Initial clinical examination:
- Visual acuity assessment
- Pupillary assessment for relative afferent pupillary defect
- Slit-lamp biomicroscopy
- Intraocular pressure measurement
- Gonioscopy (especially when iris neovascularization risk is high)
- Dilated fundus examination 5
First-line imaging:
- Optical Coherence Tomography (OCT) to evaluate macular edema and structural changes
- Color fundus photography to document retinal findings 5
Fluorescein angiography when:
- Posterior segment involvement is suspected
- Macular edema is present on OCT
- Disease activity assessment is unclear
- Treatment response needs to be evaluated 1
Evidence Supporting FA Use in Uveitis
A recent 2024 study demonstrated that ultra-wide-field fluorescein angiography (UWFFA) altered disease activity assessment in 18.3% of eyes and changed management decisions in 27.4% of eyes compared to clinical examination with only fundus photography and OCT 1. This underscores the importance of FA in the diagnostic workup.
Another study found that 79% of pediatric uveitis patients with apparently quiescent disease on clinical examination showed evidence of occult retinal vasculitis on FA 4. This highlights FA's ability to detect inflammation that might otherwise be missed.
Complementary Role of OCT and FA
While OCT is often the initial imaging test due to its lower cost, greater safety, and higher likelihood of obtaining usable information (90.4% for OCT vs. 77% for FA), the agreement between OCT and FA in diagnosing macular edema is only moderate (κ = 0.44) 2.
- OCT detects macular thickening
- FA detects macular leakage
- These are related but distinct pathological features 2
Therefore, when one test is negative but clinical suspicion remains high, performing the second test is justified.
Practical Considerations
- FA carries risks including rare severe reactions (death in approximately 1/200,000 patients) 5
- Fluorescein crosses the placenta but no documented fetal harm has been reported 6
- Patient should be informed about temporary yellow discoloration of urine 6
- Ultra-wide field angiography has become the preferred technique for evaluating intermediate and posterior uveitis as it better visualizes peripheral pathology 7
Conclusion
Fluorescein angiography provides critical information in uveitis evaluation that cannot be obtained through clinical examination or OCT alone. It should be included in the diagnostic workup of patients with suspected posterior segment involvement, particularly when treatment decisions depend on accurate assessment of disease activity.