Blindness Various scales have been developed to describe the extent of vision loss and define blindness. Total blindness is the complete lack of form and visual light perception and is clinically recorded as NLP (no light perception). Blindness is frequently used to describe severe visual impairment with residual vision. Those described as having only light perception have no more sight than the ability to tell light from dark and the general direction of a light source. UMLS:C0456909 human_phenotype MSH:D001766 Legal blindness Blindness is the condition of lacking visual perception defined as visual perception below 3/60 and/or a visual field of no greater than 10 degress in radius around central fixation. SNOMEDCT_US:65956007 UMLS:C0271215 HP:0000618 Fyler:4866 Blindness HP:0007839 Total vision loss Reduced visual acuity