Uveitis is a group of troublesome diseases that collectively represent a cause of blindness comparable to diabetes. Most forms of uveitis are either infectious or immune-mediated. The investigators propose to create a data base on peripheral blood gene expression for patients with 3 of the most important diseases associated with uveitis: ankylosing spondylitis, sarcoidosis, and Behcet's disease. The investigators will quantitatively measure the expression of consistent alteration in peripheral blood from patients with more than 40,000 gene sequences using microarray gene chip technology. This approach is known to detect systemic immune-mediated disease. The investigators will use this data base to:

1. Determine if patients with uveitis and ankylosing spondylitis, sarcoidosis, or Behcet's can be distinguished from a normal population or controls with the same systemic disease but no history of uveitis
2. Determine if the profile of gene expression can distinguish infectious or idiopathic forms of uveitis from patients with spondylitis, sarcoidosis, or Behcet's
3. Determine how this gene profile changes over time as episodic disease such as spondylitis or Behcet's activates or remits
4. Correlate the changes in gene expression with the prognosis of the ocular inflammatory process.

The creation of a gene expression data base for patients with uveitis has the potential to clarify the pathogenesis of disease, establish new diagnostic tools, and provide a means for predicting prognosis.