Dr. Caldwell is an internationally recognized expert in the field of vascular endothelial cell biology. His research program is focused on defining the mechanisms of vascular endothelial cell dysfunction in diabetes in relation to activity of the arginase enzyme. His primary interest in vision research is on the regulation of retinal vascular tone. He collaborates extensively with other members of the group and is co-investigator on two NEI-funded projects. He has applied his knowledge and expertise to studies of vascular dysfunction in models of diabetic retinopathy and retinal inflammatory disease. Dr. Caldwell serves on the thesis committees of several graduate students pursuing vision research projects and collaborates with many members of the VDI including Drs. Bartoli, El-Remessy, Smith, and R. Caldwell.