Sickle cell retinopathy and hemoglobinopathies

Sickle cell hemoglobinopathies all share the common feature of an abnormal globin chain, which leads to sickling of erythrocytes and obstruction of the microcirculation. Sickle vaso-occlusive events are insidious and affect virtually every vascular bed in the eye, often with visually devastating consequences. Vaso-occlusion most profoundly affects the retina, the light-sensitive tissue that lines the inside wall of the posterior aspect of the eye, because it is exquisitely sensitive to deprivation of oxygen. Even temporary vaso-occlusion, if longer than about 1.5-2 h, can result in permanent infarction of the retina. Most, if not all, of the complications of sickle cell disease in retina originate from the vaso-occlusive processes. The pathological changes can be divided into nonproliferative and proliferative events.