Retinal vasculitis:

To define the case as retinal vasculitis you should have the following findings

1)vitreous cells (if absent with exudates along vessels consider; diabetic retinopathy, Vein occlusion, adult Coat's, radiation or sickle cell)

2)perivascular infiltrate or sheathing in more than one vessel

3)FFA evidence of vascular leakage and/or occlusion

4)absence of multifocal choroiditis
The next step is to look for evidence of systemic manifestations or lab changes mainly
1)fever, malaise
2)arthritis
3)rash
4)CBC

5)ESR, CRP
If No systemic manifestations and negative screening labs (no need for expensive labs in these cases)
1)child----frosted branch angiitis
2)20-40----pars planitis, acute retinal necrosis, Eale's
4)40's---- birdshot, autoimmune vasculitis
5)50's+---intraocular lymphoma

If there are systemic manifestations and positive screening labs, think of and do investigations accordingly;
1)Child; exanthemata, leukemia, Kawasaki
2)20-40 male; Behçet's, Sarcoidosis, TB, HIV/CMV, Syphilis
3)female; SLE and other collagen, sarcoidosis, TB, MS
4)above 60; temporal arteritis, lymphoma
5)Immunocompromised; HIV/CMV, Syphilis, Toxoplasmosis, Systemic leukemia or lymphoma, Systemic candidiasis
6)Rare; Lyme's, Whipple's,