This work reports a case of Prader-Willi syndrome, with dyschromatopsia, its clinical characteristics and ophthalmological changes, monitoring and treatment, in a 6-year-old child. Prader-Willi syndrome is rare, being an autosomal dominant disorder caused by the exclusion of the proximal long arm of the paternal chromosome 15 (15q11-q13) or inheritance of both pairs of chromosomes 15 from the mother. Clinical m...