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Colour vision
Anatomy & Optics
Key Points
- •Normal colour vision is trichromatic (S/M/L cones) - explained by Young-Helmholtz theory at the receptor level and Hering opponent process theory at the neural processing level
- •Congenital red-green CVD is X-linked recessive, affecting ~8% of males; deuteranomaly is the most common form (~5% of males)
- •Kollner's rule: optic nerve disease → red-green defect; macular disease → blue-yellow defect
- •The anomaloscope is the gold standard for classifying and grading red-green CVD; Ishihara plates are for screening only (detect red-green, cannot classify protan vs deutan)
- •Achromatopsia (rod monochromacy): no functional cones → no colour vision, VA ~6/60, nystagmus, photophobia, absent cone ERG
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17 more sections are included with the Clinical plan.
- Definition
- Epidemiology
- Aetiology and causes
- Pathogenesis
- Classification
- Risk factors and associations