عمى الأزرق (ترايتانوبيا)

Tritanopia affects fewer than 0.01% of the population and is equally common in males and females (unlike red-green deficiencies, which are X-linked). People with tritanopia lack S-cone (short wavelength, blue-sensitive) photoreceptors, causing blue to appear greenish and yellow to appear pinkish. Purple and blue become difficult to distinguish, as do yellow and white. While rare, tritanopia can be acquired through aging, retinal disease, or medication side effects. Designing for tritanopia means avoiding blue-yellow as the sole color distinction and ensuring sufficient luminance contrast.