Vascular endothelial growth factor (VEGF)

A protein which induces the growth of new blood vessels and is usually produced in response to impaired oxygen flow to tissues. It may be produced in increased quantity in diabetic retinopathy and age-related macular degeneration.

Variable expressivity

The idea that individuals with a particular disease process will not each experience the same severity of disease. For instance, one person may have a milder form of the disease while another person with the same disease has a more severe manifestation of the disease. This is in contrast to incomplete penetrance.

Uveitis

Inflammation involving the pigmented layers of the eye (the iris, ciliary body and choroid).