Achromatopsia

Achromatopsia is a disorder in which color vision is absent or severely impaired, often alongside light sensitivity and reduced visual acuity. It can be inherited or acquired.

Cone cell: A light-sensitive retinal cell that supports color vision and detailed vision in bright conditions. Impaired cone function is central to congenital achromatopsia.
Retina: The light-sensitive tissue lining the back of the eye that converts light into neural signals. Achromatopsia arises from dysfunction in retinal cone pathways.
Achromatopsia (acquired): Loss of color vision caused by damage to visual pathways or color-processing regions rather than an inherited cone disorder. It can resemble congenital achromatopsia but begins after neurological or ocular injury.
Electroretinography: A test that records the electrical responses of retinal cells to flashes of light. It can reveal severely reduced or absent cone responses.
Rod cell: A retinal photoreceptor specialized for vision in dim light, with little role in color discrimination. Rod-mediated vision often remains functional, making the world appear in shades of gray.
Color vision: The ability to distinguish light wavelengths as different colors, mediated chiefly by cone photoreceptors. Its absence or impairment defines the disorder.
Dyschromatopsia: Impaired color discrimination in which color vision is abnormal but not necessarily absent. Achromatopsia generally causes a more profound loss than partial color deficits.
Genetic testing: Analysis of DNA to identify genetic variants associated with a condition or trait. Testing can confirm a molecular cause and support family counseling.
Phototransduction: The process by which photoreceptor cells convert light into electrical signals. Inherited forms disrupt proteins needed for cone phototransduction.
Visual acuity: The sharpness of vision, commonly measured by the smallest details that can be resolved. Cone impairment can reduce fine-detail vision as well as color discrimination.

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