Severe proliferative retinopathy as the only sign of sickle cell hemoglobin C disease

A 48-year-old black woman developed severe bilateral hypoxic proliferative retinopathy without other clinical manifestations. The hemoglobin level was 10.6 to 11.5 g/100 ml, reticulocyte level was 2.2%, targeted and sickled red blood cells were seen on blood smears, and hemoglobins S and C were demonstrated by electrophoresis. Glucose tolerance test was normal. The development of neovascular proliferation, vitreous hemorrhage, and retinal detachment unassociated with other clinical symptoms is unusual in sickle cell hemoglobin C disease.