Additionally, it has been suggested that American/Western BD patients may have different disease characteristics than their Mediterranean counterparts. The disease characteristics of American/Western and Mediterranean BD patients will be compared and evaluated. Blood samples from BD participants that have participated in other NIH protocols where participants consented for other or future use of samples has been obtained will be collected (particularly from current participants of NIH protocol 03-AR-0173 in which NEI is a collaborator). In summary, the results will be analyzed with respect to disease in different ethnic groups, and clinical features of the disease (e.g., ocular vs. non-ocular involvement, active vs. quiescent disease).