Characteristics of colour vision disorders
In colour vision disorders, the perception of some colours is reduced. Statistically, the most common of these is green colour blindness (deuteranomaly). In colour blindness (achromatopsia or achondroplasia), we distinguish between the following conditions:
- Achondroplasia > total colour blindness
- Monochromasia > only one colour is perceived
- Dichromasia > two colours cannot be distinguished
Men are affected more frequently
As colour vision disorders are predominantly congenital and carried the X chromosome, these disorders affect 8% of men and only 0.4% to 1% of women. The imperfect gene causes a reduction or even absence of certain colour cells in the retina. This leads to a faulty mixing of colours in the brain. There are three cell types in total: rods for the perception of red, green and blue.
Treatments for colour vision disorders
A colour vision disorder is diagnosed at the ophthalmologist with appropriate tests. There are currently no treatments to replace the missing cells. The most common colour vision disorders include green and red-green colour-blindness. Colour vision disorders are only rarely the result of certain eye diseases, such as cataracts or glaucoma, and have a chance of being corrected.
Contrast vision disorders
Unlike colour vision disorders, contrast vision disorders are often acquired. This is the ability or inability to perceive different brightness levels or shades of grey. Most often, the light entering the eye is compromised. This means that media opacities such as corneal changes of all kinds, lens opacities (cataracts), vitreous impurities (haemorrhages) or optic nerve diseases (glaucoma) are the culprits and very often treatable.
How is a contrast vision disorder recognised?
The measurements are made with so-called Landolt rings with different brightnesses, with and without glare. These methods are particularly important in car license and airworthiness examinations. You will probably have come across some of these tests during childhood.
Would you like to be tested? Testing is totally uncomplicated and quick. We will be happy to advise you at our practice at Zurich Bellevue.