420 mongoloid children aged between one month and 14 years were examined in a special ophthalmology department for disabled children employing biomicroscopy, retinoscopy under atropine and, if possible, visual acuity testing. Epicanthal folds were present in 46%, mongoloid slanting of the lids in 72% of cases. A decrease in binocular vision was present in 40% of the children. Brushfield's spots were encountered in 86% of the patients in a circular arrangement, whilst in 7% only the temporal half of the iris was involved. Lens changes of a variable degree were present in altogether 55% of cases and an increase in the number of retinal vessels, as well as their radial arrangement, as described by Williams, were documented in 46% of the cases. A comparison of the incidence and degree of refractive anomalies in mongoloid and normal children was undertaken. The present findings are discussed and compared with the results of other investigators.