Behaviour of untreated proliferative sickle retinopathy.

The development of ocular lesions in 313 patients with sickle cell disease followed up for periods of 1--8 years is described. Proliferative sickle retinopathy (PSR) was present on initial examination in 68 (12%) of 567 eyes and developed in a further 46 (8%) eyes during the study period. Spontaneous regression (autoinfarction) was present on initial examination in 33 (49%) eyes with PSR initially and developed in a further 45 (39%) eyes during the study. Development of PSR was more common in sickle cell-haemoglobin C (SC) disease, and autoinfarction appeared to occur more commonly in homozygous sickle cell (SS) disease. The two processes were delicately balanced, and some PSR lesions lasted less than a year before undergoing autoinfarction. Although the high prevalence of autoinfarction diminishes the clinical sequelae of PSR, blindness related to PSR occurred in 14/119 (12%) eyes. Autoinfarction closes the feeding vessels of PSR lesions more elegantly than, and without the complications associated with, photocoagulation. A greater understanding of factors involved in the progression and regression of PSR is relevant to defining the role of photocoagulation in this condition.