Colour vision testing

Ishihara Test

Demonstration plate: visible by all persons, normal or color blind Transformation plates: normal people will see different numbers than individuals with colour vision defects, and people with total color vision defects will not see any number Vanishing plates: only normal people will see numbers Hidden digit plates: normal people will not see any numbers Diagnostic plates: to determine the type of color vision defect (protanopia or deuteranopia) and the severity Tracing plates: for illiterate persons

Red-green color vision deficiency

Type 1 (protan defects): affect the red cones (L-cones)

Protanomaly: certain shades of red look more green and less brightProtanopia: unable to tell the difference between red and green at all

Protanopia: unable to tell the difference between red and green at all

Type 2 (

Deutan defects: affect the green cones (M-cones) Deuteranomaly: certain shades of green look more red (most common type of red-green color vision deficiency) Deuteranoia: unable to tell the difference between red and green at all

Protan defects: affect the L-cones (red)

Protanomaly: certain shades of red look more green and less bright Protanopia: unable to tell the difference between red and green at all

Blue-yellow color vision deficiency Tritan defects: affect the blue cones (S-cones)

Tritanomaly: hard to tell the difference between blue and green and between yellow and red Tritanopia: unable to tell the difference between blue and green, purple and red, and yellow and pink, colors look less bright

Complete color vision deficiency/monochromacy/achromatopsia (rare) Can't see colors at all, may also have trouble seeing clearly, and may be more sensitive to light

Protanopia: Deuteranopia Type 1 color vision/monochromacy/achromatopsia: rare condition where individuals cannot perceive any colours, seeing the world in shades of grey, black, and white, because of lack of functional cone cells, which are responsible for color vision

Reading list: https://www.ophthalmology24.com/types-of-color-blindness