Achromatopsia

Description

Achromatopsia is a disorder that causes problems with colour vision. The retina, which is the light-sensitive tissue at the back of the eye, contains two types of light receptor cells called rods and cones. Rods provide vision in low light (night vision), while cones provide vision in bright light (daytime vision). Cones are also responsible for colour vision. 

There are two types of achromatopsia: complete and incomplete. People with complete achromatopsia cannot perceive any colour; they see only black, white, and shades of gray. People with incomplete achromatopsia can see some colour.

People with achromatopsia may have additional problems with their vision, including an increased sensitivity to light and glare (photophobia), involuntary back-and-forth eye movements (nystagmus), and significantly reduced sharpness of vision (low visual acuity). Affected individuals may also have a small visual blind spot (scotoma), farsightedness (hyperopia), or nearsightedness (myopia).

Achromatopsia is different from the more common forms of colour vision deficiency (also called colour blindness), in which people can perceive colour but have difficulty distinguishing between certain colors, such as red and green. One form of colour blindness, called blue cone monochromacy (BCM), is sometimes considered a form of incomplete achromatopsia. 

Inheritance patterns

The source lists the following possible inheritance patterns: Autosomal recessive. More than one pattern can apply in different cases.

Related genes

• CNGA3

• CNGB3

• GNAT2

• PDE6C

• PDE6H

• ATF6

Other names

ACHM

Achromatism

Rod monochromatism