**3. Indications**

Accurate diagnosis of the etiology behind intraocular inflammation is essential in order to provide the proper treatment and management and for prognostic reasons. While the general approach to uveitis patients includes history taking, review of systems, examination, and ancillary tests, at times none of these result in a conclusive diagnosis. In these atypical cases a diagnostic vitrectomy may lead to the correct diagnosis. An example for such an indication is primary intraocular lymphoma (PIOL), which requires a definitive tissue diagnosis to diagnose and commence treatment.[3]

Another indication for this procedure is failure of conventional therapy. While this might result from an intractable disease, it may also be the result of a misdiagnosis, requiring an invasive approach to reach the correct diagnosis.

A third indication is a sight-threatening disease, where the disease rapidity necessitates an invasive approach for diagnosis, and at times also for treatment. Examples for infectious entities that correspond to this description include infectious endophthalmitis [4] and ARN. [5]
