270 consecutive patients with rheumatoid arthritis who had received chloroquine therapy were examined ophthalmologically for toxic retinal lesions. The total annual dose of chloroquine was 70-75 g. The maximum total dose given was 1330 g. The duration of treatment ranged up to 15 years. The primary material was divided into four groups according to total chloroquine dose received: greater than 100 g, 101-300 g, 301-600 g, and less than 600 g. Each dose group was arbitrarily split into two age groups, one with patients under 63 years of age and the other with patients over 63, in order to analyse the effect of age upon the ocular findings. In the present study, slight macular changes were included in the concept of maculopathy and were not thought to contra-indicate chloroquine therapy. Macular changes were found in about 25% of the patients, regardless of age in the lowest dosage group. The frequency of maculopathy increased with increasing total dose only in the older age group. It was also shown that the frequency of maculopathies and other eye diseases also increased with increasing age. This was evident even from the age of 50. The only patient with chloroquine retinopathy was an inadequately controlled 74-year-old woman. Chloroquine treatment of rheumatoid arthritis in the absence of any other disease which may cause retinopathy implies negligible risks in adult patients under 50 years of age. These patients could be less frequently checked. Older patients require regular ophthalmological checks. It is important to use the smallest effective dose possible, and never higher than 4 mg of chloroquine phosphate/kg body weight and day for 10 months annually; in elderly patients, preferably even lower doses.