THE TAPETUM lucidum, an iridescent cellular or noncellular layer of the choroid, which is responsible for the metallic reflex seen at night in the eyes of many mammals, is not present in the human eye. However, in rare instances a ta[etal-like retinal luster has been observed ophthalmoscopically. In the 2 cases described by Mann1 the abnormality occurred in women and was unaccompanied with any impairment of vision. Concerning one of these women, it was said that in childhood "her eyes used to glow in the dark like an animal's.'' Dr. Mann's patients were not known to be related, and their families were not investigated.2 To our knowledge, only 1 other instance of a tapetal reflex has been mentioned in the ophthalmologic literature, this being the case of a woman described by Niccol.3 During the course of a genetic study which originated with a 30 year old man