![]() Second, the uncontrolled, repetitive, back-and-forth eye movements occur, which are diagnosed as nystagmus. First, the child avoids daylight, which is the symptom of photophobia – an increased sensitivity to light connected with strong discomfort or eye pain during the exposure to daylight. Symptoms of Achromatopsia appear in the first few months of life and can be observed by parents of the child with non-functioning cones. ![]() It is estimated that 75% of Achromatopsia cases are caused by mutations in genes CNGA3 and CNGB3 3. ![]() It is notable that cones of incomplete Achromats do not lose their function entirely, enabling people to see a limited number of colours and decreasing the severity of other visual problems. Losing their functionality, cones do not participate in transmitting visual signs from the eye to the brain – the process is thus entirely operated by rods, which results in lack of colour vision and emerging of other severe visual symptoms. Because of congenital mutations in genes CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, OPN1LW or OPN1MW 2, cones cannot function properly, which leads directly to Achromatopsia. These light receptor cells are responsible for transmitting visual signs to the brain, providing night and daylight vision, including colour vision, which is enabled by red, green and blue cones. CausesĪchromatopsia is a genetic disorder of the retina – a part of the eye which consists of rods and cones. A non-profit Colour Blind Awareness’ Community compares Achromats’ visual experience to “seeing the world on an old black and white television set” 1 and presents Achromats’ vision among other types of colour blindness, such as Trichromacy and Dichromacy (see Types of Colour Blindness*). Achromatopsia, also known as monochromacy, is a type of colour blindness. Achromatopsia is a non-progressive disorder, related to several other problems with vision, such as photophobia, nystagmus and low visual acuity. The incomplete Achromats have some functional cones in the retina and less severe visual symptoms. On the other hand, the incomplete type of this disorder is much milder and connected with discrimination of some colours. Complete Achromats have no functional cones in the retina and suffer from severe visual aberrations. The complete Achromatopsia enables people to see only white, black and many shades of grey, without perceiving any colours. There are two types of Achromatopsia: complete and incomplete. Achromatopsia is a rare and hereditary visual disorder caused by the absence or impairment of functional cones in the retina.
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