Achromatopsia

Achromatopsia is a visual disorder characterised by the absence of colour vision, nystagmus (involuntary movement of the eyes), light sensitivity, and reduced vision. It is hereditary and non-progressive. The cause is the absence of functioning cones in the retina, which is at the back of the eye. The cones are light sensitive photoreceptor cells that are responsible for your colour vision and ability to see fine detail.

Patients that have complete Achromatopsia see the world in black, white and shades of grey. Patients with incomplete Achromatopsia have less serve visual symptoms as they still have some functioning cones.

Achromatopsia is not the same as red/green colourblindness.

Absence of colour vision

Nystagmus – involuntary eye movements/shaking eyes

Photophobia -Light sensitivity

Reduced vision

Achromatopsia is a genetic condition where a baby is born without functioning cones.

CNGA3, CNGB3, GNAT2, PDE6C, PDE6H and ATF6 are the known gene mutations to cause Achromatopsia. There are three types of cones, red, green and blue. You need all three to detect colour and have normal vision.

Achromatopsia is normally detected at your routine eye test. Patients typically complain of light sensitivity and have poor vision, which cannot be resolved with correction. Advanced retinal imaging such as an OCT scan of your central vision (the macula where the cones are located) would also show results of abnormality, further assisting in the diagnosis.  A colour vision test such as Ishihara (H-R-R & City University colour vision tests can also be used) would detect the patient’s absence of colour vision indicating further investigation with an Ophthalmologist. A specialised test such as the ERG (electroretinography) would also help confirm the diagnosis as specific waveform shapes are detected in patients with Achromatopsia.

Unfortunately there is no cure for Achromatopsia, however there is ongoing medical research on gene therapy.

Patients with Achromatopsia including children should have regular eye tests to assess for a glasses prescription. Correction of a patients prescription with glasses or contact lenses may help improve limited vision but not give patients with Achromatopsia the same normal levels vision as patient's that do not have the condition.

Red coloured lenses may help reduce light sensitivity and may improve visual function. A newer device such as eyeborg may also help patients with no colour vision to perceive colours.

Children can usually attend mainstream school with help from governing bodies. Large print books, a front seat in the classroom and magnifying devices have been found to be helpful. A low vision assessment would need to be performed via the Ophthalmologist before school starts to assess the visual needs of the child.

For further help and information:

https://www.rnib.org.uk/nb-online/life-in-black-and-white

https://www.rnib.org.uk/supportingyou