Achromatopsia (complete color blindness)

What happens in this disease?

The retina has two kinds of light cells: rods and cones. Cones allow vision in daylight, color vision and sharp vision. In achromatopsia, the cones do not work at all or work very little. The disease usually does not progress; symptoms stay similar throughout life.

Which symptoms can occur?

Symptoms begin in the first weeks after birth. The first thing noticed is usually shaking of the eyes.

• Involuntary shaking of the eyes, called nystagmus
• Extreme sensitivity to light and glare
• Clearly reduced vision, blurred vision
• Seeing no colors or very few colors
• A small blind spot in the middle of the field of vision
• Refractive errors such as hyperopia or myopia

How is it diagnosed?

The eye doctor tests sharpness of vision, color vision and the field of vision. An ERG test shows whether the cones respond to light. Imaging methods such as OCT show the structure of the retina. A genetic test supports the diagnosis.

Treatment and care

There is no approved treatment at the moment. Care aims to ease the symptoms. Glasses with special filters, dark glasses or red-tinted lenses can reduce light sensitivity. Magnifiers and other low vision aids make reading easier. At school, it helps for the child to sit in the front row and away from the window. Eye checks are recommended every 6 to 12 months in childhood and every 2 to 3 years in adulthood. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

It is inherited recessively. For a carrier couple, the chance of an affected child in each pregnancy is 1 in 4. Carrier mothers and fathers usually have no symptoms. This chance can be higher when parents are related by blood. Girls and boys are affected equally often. Genetic counselling is recommended.