The patient had severe peripheral nonperfusion with associated neovascularization and old vitreous hemorrhage in each eye. The most common cause in a young African-American person is sickle retinopathy. Patients with SS disease have the “S” hemoglobin variant on both DNA strands and usually have anemia with red blood cells that tend to transform to a “sickle” configuration that obstructs capillary blood flow. Those with SC disease have the S variant on one allele and the “C” variant on the other allele. Alone, the C variant does not cause significant anemia or other problems. Patients with SC disease tend to have less severe anemia but, curiously, more severe retinopathy than those with SS disease. Our patient had hemoglobin electrophoresis and was found to have SC disease.
Patients with sickle retinopathy typically have peripheral nonperfusion and fronds of neovascularization that resemble sea fans. Because patients with sickle retinopathy are often young people with extensive posterior hyaloid attachment to the retina, preretinal hemorrhages often localize to the subhyaloid space, resulting in oval patches of hemorrhages (“salmon patch” hemorrhages). The trapped blood can induce pigment migration, leading to patches of hyperpigmentation known as “sunburst spots.” In our patient, salmon patch hemorrhages can be seen in the temporal periphery of the right eye, and a sunburst spot can be seen in the temporal periphery of the left eye at about 2:30.
There are other diagnostic considerations in patients with bilateral peripheral nonperfusion. These include retinal vasculitis from causes such as Eales’ disease, Behcet’s disease, sarcoidosis, and lupus retinitis. Our patient did not have clinical evidence of active retinitis, and blood testing did not support these diagnoses. Another possibility is familial exudative vitreoretinopathy, a genetic disorder with highly variable penetrance that features peripheral nonperfusion. There is often temporal dragging of blood vessels, which can resemble inactive retinopathy of prematurity. Other causes of peripheral nonperfusion, for which accompanying history and/or findings are lacking in this patient, include retinopathy of prematurity, incontinentia pigmenti, branch retinal vein occlusion, talc retinopathy, radiation retinopathy, diabetes, and chronic myelogenous leukemia.
Evidently, our patient’s retinal detachment was due to vitreoretinal traction from largely fibrosed peripheral neovascularization. Peripheral panretinal photocoagulation to the areas of ischemia was performed in both eyes, and two years later our patient had a visual acuity of 20/25 OD and 20/20 OS without correction. There was no active neovascularization in either eye.