A person has defective blue colour apprec-iation. His condition is better named as

D. i.e. Tritanomalous Suffix "anomalous" is used for defective colour visionQ & Suffix "anopia" is for absent colour visionQ Term Meaning Nyctalopia Night blindness Hamarlopia Day blindness Achromatopsia Colour blindness Trichromate Individual with normal colour vision Protanomalous Defective red colour appreciationQ Deuteranomalous Defective green colour appreciationQ Tritanomalous Defective blue colour appreciationQ Protanopia Complete red colour blindnessQ Deuteranopia Complete green colour blindnessQ Tritanopia Complete blue colour blindnessQ Mnemonic "BuT GoD RePly Daily & Humoraly" Mnemonic BuT Blue = Tritanopia / Tritanomalous GoD Green = Deuteranopia / Deuteranomalous RePly Red = Protanopia / Protanomalous Daily & Day = Hamarlopia Humorally blindness So anopics have dichromatic colour vision i.e. (are able to see two primary colours) & anomalous have trichromatic colour vision with anomaly (i.e. mechanism to appreciate all 3 primary colours is present but is defective for one or two of them) Protan means first, deuteran means second, and tritan means third. According to decreasing wavelength it is used for red (550-570 nm, so protan), green (520-540 nm, so deuteran) and blue (410-424 nm, so tritan)