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Color Blindness
Aka: Color Blindness, Color Blind, Color Vision Deficiency, Blue-Yellow Color Blindness, Blue-Yellow Dyschromatopsia, Tritanomaly, Tritanopia, Tritan defect, Red-Green Color Blindness, Red-Green Dyschromatopsia, Deuteranomaly, Deuteranopia, Deutan defect, Red Color Blindness, Protanopia, Protanomaly, Protan Defect, Blue Cone Monochromacy, Achromatopsia, Monochromacy
- See Also
- Retina
- Pathophysiology
- Each of three cone types contains a specific opsin photopigment, and each is encoded by a specific gene
- L-Cones (long wave length cones, yellow-orange, OPN1LW gene)
- M-Cones (middle wave length cones, yellow-green, OPN1MW gene)
- S-Cones (short wave length cones, blue-violet, OPN1SW gene)
- Genetic Defects
- Red Green Color Blindness
- Genetic defect of OPN1LW or OPN1MW
- Abnormal opsin pigments or absent L-Cones or M-Cones
- Blue-Yellow Color Blindness
- Genetic defect of OPN1SW
- Defective S-Cones or premature destruction of S-Cones
- Complete Color Blindness (Blue Cone Monochromacy)
- Genetic defect in both OPN1LW and OPN1MW
- Defective L-Cones and M-Cones, leaving only functional S-Cones
- Acquired Defects
- Glaucoma
- Retinitis Pigmentosa
- Vitamin A Deficiency
- Alcoholism
- Toluene Poisoning
- Medications (e.g. Ethambutol, Phenytoin, Phosphodiesterase Inhibitor)
- Types
- Red-Green Color Blindness
- Most common Color Blindness types
- Far more common in males (X-Linked)
- Males (1 in 12 of northern european descent)
- Females (1 in 200 of northern european descent)
- Difficulty distinguishing between red and green
- M-Cone Disorders (related to green Perception)
- Deuteranomaly (most common, dysfunctional M-Cones)
- Green appears similar to red (mild dysfunction)
- Deuteranopia (loss of M-Cones)
- Unable to differentiate green and blue (severe dysfunction)
- Results in dichromic Vision (red-blue Vision only)
- L-Cone Disorders (related to red Perception)
- Protanomaly (dysfunctional L-Cones)
- Red appears similar to green, and more dull (mild dysfunction)
- Protanopia (loss of L-Cones)
- Unable to differentiate green and blue (severe dysfunction)
- Results in dichromic Vision (green-blue Vision only)
- Blue-Yellow Color Blindness (Tritan defects)
- Less common Color Blindness types (<1 in 10,000 persons worldwide)
- Difficulty distinguishing between blue and green as well as blue and black
- S-Cone Disorders (related to blue Perception)
- Tritanomaly (dysfunctional S-Cones)
- Difficulty distinguishing between blue and green
- Difficulty distinguishing between yellow and red
- Tritanopia (loss of S-Cones)
- Difficulty distinguishing between blue and green
- Difficulty distinguishing between purple and red
- Difficulty distinguishing between yellow and pink
- Colors appear dull
- Complete Color Blindness (Blue Cone Monochromacy, Achromatopsia)
- Rare (<1 in 100,000 persons worldwide)
- Autosomal Recessive genetic disorder
- Results in severe reduction in color Vision and poor Visual Acuity
- May also be associated with photophobia, Nystagmus and Myopia
- Diagnosis
- Color Vision Test (e.g. Ishihara Color Test)
- Management
- Treat underlying causes in acquired Color Blindness
- Eyeglass or Contact Lens colored filters may enhance color contrast and differentiation
- Resources
- Color Blindness (NIH, for patients)
- https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/color-blindness/types-color-blindness
- Color Vision Deficiency (Medline Plus)
- https://medlineplus.gov/genetics/condition/color-vision-deficiency
- References
- Naifeh (2021) Color Vision, Stat Pearls, accessed 12/13/2021
- https://www.ncbi.nlm.nih.gov/books/NBK470227/