ACE and blood pressure trait: Interventional studies with angiotensin converting enzyme inhibitors have shown a reduction in progression of retinopathy in adults with type 1 diabetes,35 in the absence of hypertension, and in type 2 diabetes.36, 37 Although this suggests that lowering of high blood pressure influences the risk of retinopathy, these drugs may have benefits on the eye independent of their antihypertensive properties, possibly by affecting local production of angiotensin converting enzyme by retinal vascular endothelial cells.38