Hypomelanosis Ito (HI) is a very rare neurocutaneous syndrome which is often associated with cutaneous, cerebral, musculoskeletal and ocular abnormalities. The paper deals with changes in familial HI (mother and daughter) with special consideration of ocular symptomatology; it also presents a review about the relevant literature published to date--not documented with photographs with one exception. The argument is raised whether all ocular changes described in HI actually belong to the syndrome or are partly a mere coincidence. There is also a description of a cataract which has never been observed in cases of HI. Electrophysiological tests (electroretinography, electro-oculography, visual-evoked potential) which to date have not been carried out for HI, are presented and their results reported. Mention is also made of the hereditary factor which has so far been questioned; it is assumed that it is autosomal dominant in character. In this context, the results of a chromosome analysis in both mother and daughter are presented.