Summary of Colour Vision Deficiency and Testing

What is Colour Vision Deficiency?

  • Inability or decreased ability to perceive colors under normal lighting.
  • Caused by absence of color-sensitive pigment in the cone cells of the retina.

Causes of Color Blindness

  • Genetic inheritance through X chromosome.
  • Sons can be color blind if the mother carries the gene; daughters may be carriers but not affected.

Types of Colour Vision Deficiency (CVD)

  1. Red-Green Deficiency
    • Most common, difficulty distinguishing reds and greens.
  2. Blue-Yellow Deficiency
    • Rare condition, difficulty distinguishing blue from green, yellow may appear pale.

Specific Types of CVD

  • Protanopes: Cannot see red.
  • Deutranopes: Cannot see green.
  • Tritanopes: Cannot see yellow or blue.

Treatments for Color Vision Deficiency

  • No definitive treatment available.
  • Color filters/contact lenses may enhance brightness.
  • Gene therapy showed promise in research for restoring color vision in non-human studies.

Ishihara's Colour Blindness Test

  • Main test for red/green color blindness, not effective for blue color blindness.
  • Contains 24 plates with colored dots to determine vision ability.
  • Plate responses categorized to assess color vision:
    • Normal vision can read more than 9 plates correctly.
    • Fewer than 9 plates indicates color deficiency.

Challenges Faced by Color Blind Individuals

  • Difficulty in tasks like choosing food, gardening, sports, driving, and understanding emotional cues through facial color changes.