‘Foveal Tritanopia’

IN his book on colour vision, Dr. W. D. Wright1 discusses blue-blindness of the retinal fovea, which was described by A. Koenig2 fifty years ago and is now maintained by Willmer3 and himself for the same reasons: “This effect does not appear to have been the subject of further extensive study and although other workers were aware of Koenig's observation the general attitude appears to have been one of scepticism. Indeed most people either ignored or were ignorant of the phenomenon until Willmer recently reawakened interest in the subject.” Dr. Wright has apparently overlooked the controversy between E. Hering and A. Koenig.