Chloroquine retinopathy in Nigerian patients with heart block.

Twenty-six patients with heart block were examined for evidence of chloroquine retinopathy. Detailed histories of chloroquine intake showed that 50% (13 of 26) of these patients were chloroquine abusers. Retinal changes typical of chloroquine retinopathy were seen in 53.8% (7 of 13) of the chronic chloroquine abusers. Patients with heart block of unknown cause should have their fundi examined so that signs of chloroquine retinopathy may be sought.