To more clearly ascertain the relationship between ocular manifestations of sickle cell disease and diabetes, specifically; whether the presence of sickle cell trait exacerbates the disease progression of diabetic retinopathy.

The objective of this research study is to evaluate the relationship between sickle cell trait and the progression of diabetic retinopathy. People with diabetes have high blood sugar that damages small blood vessels. Damage to the blood vessels that supply the retina in the back of the eye is called diabetic retinopathy. Diabetic retinopathy is worse in African-Americans with diabetes, with earlier and more severe disease progression and common complications including vitreous hemorrhage - where these blood vessels in the eye leak - and retinal detachment - the separation of the nerves of the retina from the back of the eye which may lead to blindness. One explanation for this increased severity of diabetes in African-Americans is the presence of sickle cell disease, or even just sickle trait, which causes damage to red blood cells and blood vessels under conditions of stress; like low oxygen levels, or hyperglycemic acidosis.

Inclusion Criteria:

• Self-identified African-American patients with diabetes will be identified from Dr Bowie's retina clinic at Storm Eye Institute.
• These subjects are either being screened or treated for the progression of diabetic retinopathy.

Exclusion Criteria:

• None

African-Americans with type II diabetes mellitus experience increased systemic vascular morbidity and mortality, even after adjustment for socioeconomic factors.