Retinopathy in patients with sickle cell trait."BACKGROUND:  Sickle hemoglobinopathies are among the most prevalent genetic disorders in the United States. Sickle cell trait (hemoglobin AS) is the most common genotype and has traditionally been considered a benign condition. Systemic and ocular complications are seen infrequently in patients with sickle cell trait. In the presence of concomitant systemic diseases or trauma, however, marked retinopathy can occur. The presence of retinopathy in patients with sickle cell trait necessitates a comprehensive medical workup, including serologic testing to rule out systemic conditions. CASE REPORTS:  Two cases are presented. The patient in case 1 is a 44-year-old black man with a positive history of sickle cell trait and uncontrolled hypertension. Best-corrected visual acuities (BCVAs) were 20/20 in the right eye (O.D.) and the left eye (O.S.). Retinal evaluation found vitreo-retinal fibrotic scaffolding and ""sea-fan"" neovascularization. The patient in case 2 is a 45-year-old black woman who presented after a stroke 1-month prior. Her medical history was positive for hypertension, hypercholesterolemia, a recently diagnosed aneurismal dilation of the ascending thoracic aorta, and sickle cell trait. BCVAs were 20/20 O.D., and 20/20 O.S. A single dot hemorrhage was evident O.D., and an inferior-temporal branch retinal artery occlusion with an adjacent area of sea-fan neovascularization was observed O.S. CONCLUSION:  Sickle cell disease remains a major public health concern because of its associated significant morbidity and mortality. Sickle cell trait is considered benign in a healthy patient. However, under conditions of stress, concomitant systemic diseases, or trauma leading to hypoxia, sickle cell trait can become a pathologic risk factor."