High demands are made on the visual perception of individuals involved in driving, navigation and aviation. Aphakic subjects in particular may attain good central function after operation, but are subject to stringent regulations with regard to their fitness to drive, etc. Their uncorrected vision and visual fields are poor. If only one eye is aphakic there are problems especially with binocular vision. Only the implantation of an artificial lens can return the eye to a "normal" condition. Since, for many patients, driving etc. is an essential part of their occupation, there is also a social problem involved. The authors believe that such considerations justify implantation of a lens. Even where very high demands are made on function, as in the case of airline pilots, vision is fully satisfactory for traffic purposes following artificial lens implantation.