Undergrad Rounds: Color Blindness

Retinal Color Blindness

The form of color blindness that results from the disruption of one or more cone types. 

Cortical Color Blindness

The form of color blindness that results from damage to the visual cortex. Cones are fully functional, but damage such as strokes or traumatic brain injuries impacts color vision in half of the visual field. 

Genetic Mutations

Color blindness is genetically inherited, and the gene responsible is found on the X chromosome (making it more common in males since they only have one). Mutations in OPN1LW and ON1MW (red-green), and OPN1SW (blue-yellow) cause different types of color deficiency by affecting the opsin that detects color in cone cells. 

Environmental Factors

Color blindness can happen from injury or illness that affects the visual cortex of the occipital lobe, such as eye diseases, such as glaucoma or age-related macular degeneration (AMD). Alzheimer’s or multiple sclerosis can also cause color deficiency. 

Treatment

Some special lenses or glasses can improve discrimination between colors. They work by increasing the contrast between wavelengths and reshaping the light spectrum, making colors more distinguishable to the brain. 

Also have gene replacement theory, where a vector is used to deliver a correct gene copy to the cone cells to restore or improve their light sensitivity.