Sickle cell disease is a genetic condition where the gene that makes hemoglobin (the protein in red blood cells that carry oxygen) is abnormal. Everyone inherits two genes for hemoglobin, one from each parent. If both genes are abnormal, you have sickle cell disease. If only one gene is abnormal, you have sickle cell trait which is normally asymptomatic. However, both sickle cell trait and sickle cell disease can result in sickle cell retinopathy. Due to this abnormal gene, when oxygen levels are low, the protein can become misshapen resulting in distorted or sickle shaped red blood cells. These red blood cells can clog capillaries (the tiniest blood vessels) resulting in areas of no blood flow. This in turn causes a worsening of the lack of oxygen and nutrients in the tissues downstream from the blockage, resulting in the release of chemicals like vascular endothelial growth factor (VEGF). In the retina, VEGF causes abnormal blood vessels to grow in the retina. These abnormal blood vessels can bleed into the eye (vitreous hemorrhage) or contract resulting in tractional retinal detachments. Patients who have sickle cell disease or sickel trait can develop sickle cell retinopathy. Sickle cell retinopathy is treated with laser, surgery, or rarely injections. If you or someone you know has sickle cell disease or is a relative of someone with sickle cell disease, you should be seen by a retinal surgeon to prevent the development of complications leading to permanent vision loss.