The most common symptoms of posterior uveitis are blurred vision and floaters, and the most common signs are chorioretinal infiltrates and vitreous cells. 

Posterior uveitis is diagnosed by slit lamp examination and indirect ophthalmoscopy. Imaging modalities, including fundus autofluorescence, fluorescein angiography, indocyanine green angiography, and optical coherence tomography, are key to establishing the extent of disease, identifying complications such as macular edema, and for monitoring disease progression or remission. 

A work up for underlying etiologies is always part of the diagnostic process and is particularly important to distinguish between infectious and non-infectious etiologies. The work up should be guided by the history, review of systems, and examination and imaging findings. For example, HLA A29 testing for birdshot chorioretinopathy should only be done if the examination or imaging show fundus lesions that are consistent with the disease, as approximately 10% of patients of European descent will be HLA-A29 positive, but only a very small minority of these patients will ever develop birdshot chorioretinopathy. However, there are some etiologies that should always be tested for. In particular, serologies for syphilis and a chest X-ray to evaluate for sarcoidosis and tuberculosis should be ordered. Intraocular lymphoma can masquerade as posterior uveitis and should be considered particularly in older patients and those who do not respond to treatment for uveitis as expected