Retinal neovascularization in sickle cell retinopathy.

Neovascularization of the retina occurs in several types of sickle cell hemoglobinopathies and is highly characteristic in appearance. It arises in the equatorial plane of the fundus following preliminary arteriolar occlusions and arteriolar-venular anastomoses. Neovascular sea fans arise at the interface of perfused and nonperfused portions of the retina, starting during the first decade of life and continuing for many years thereafter. Although some sea fans undergo spontaneous autoinfarction, most show progressive growth and constant intravitreal transudation of plasma components. Traction on the sea fans and the retina results in bleeding into the vitreous, retinal tears, and retinal detachment. Therapeutic intervention with a variety of coagulative techniques is feasible and is usually indicated whenever sea fans are discovered. All therapeutic modalities are capable of inducing significant complications. This is particularly true of argon laser photocoagulation when energy is concentrated into small areas (less than 200 mu) for short durations (less than 0.2 second). With appropriate precautions, photocoagulation results in a high rate of successful obliteration of neovascular tissue. Both vitrectomy and scleral buckling are valuable therapeutic procedures, but both have disproportionately high complication rates in eyes with the propensity for intravascular sickling of erythrocytes. Specific prophylactic measures are therefore indicated when these operative techniques are employed in patients with sickle cell diseases.