Dyschromatopsia is a form of color vision impairment (often generically called "color blindness"). Essentially, the eye doesn't process colors fully because one of the systems responsible for color perception isn't working properly. This makes it difficult to distinguish certain hues, especially in certain combinations (for example, red/green or blue/green).

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How Color Vision Works

The retina contains cones, light-sensitive cells that enable color vision. There are three types of cones, each more sensitive to a different portion of the spectrum (red, green, blue). The brain combines this information to create color perception. If one of the three systems is absent or impaired, color discrimination changes.

Dyschromatopsia and other color defects

In common parlance, "color blindness" is often referred to, but it's useful to distinguish between:

Dyschromatopsia / color vision deficiency: a general term

Dichromatopsia: a condition in which one of the three color channels is absent or malfunctions

The most common forms include:

Protan (red)

Deutan (green)

Tritan (blue)

Is it always congenital?

No. It is most often present from birth and has a genetic basis (especially the red-green forms), but it can also be acquired over time due to ocular or neurological causes, trauma, or certain medications. If a person notices a sudden change in color perception, it is important to have a thorough visual evaluation.

How to Detect

Color vision is assessed with specific tests, including:

Ishihara plates (colored dots with numbers/figures)

Color arrangement tests (ordering colors and shades)

These are simple but very useful tests, especially during school-age children, in the workplace, and when the patient has concerns.

Lenses that Help: What They Really Can Do

It's important to be clear here: filter lenses do not "cure" dichromatopsia and do not restore normal color vision. However, in some cases, they can increase the contrast between colors that the patient confuses, making some differences more noticeable in everyday life.

Types of optical aids that can help

Glasses with color filters/selective filters

Filter contact lenses (in selected cases)

These aids may be helpful for some people, but:

They do not work the same way for everyone

The result depends on the type of color defect

They often improve contrast in specific situations, not "all colors"

What to expect in practice

Many people with dichromatopsia adapt very well in everyday life. The most common difficulties arise when relying on color codes (school, work, maps, cables, signs, graphs). In these cases, an optometric/orthoptic evaluation and a filter trial can be helpful to determine if there is a real functional benefit.

When to have a checkup

It's advisable to schedule a checkup if:

a child often confuses colors

there are concerns at school or in sports

an adult notices a recent change in color perception

an evaluation is needed for work or competitions

you want to understand if lenses/filters can really help you

Contact us for a consultation!