Colour Vision Test for the Driving Licence: What Is Checked and Who Needs It?

When people talk about the driving licence eye test, they usually think of the eye chart and the Landolt rings. But there is another part of vision that matters for driving: colour vision. Traffic lights, road signs and brake lights all use colour to send information, so the ability to tell colours apart is important, especially for professional drivers. This article explains the colour vision test for the driving licence: what is checked, who has to take it, and what happens if the result is not perfect.

The colour vision test for the driving licence is not the same as the standard eye test at the optician. For a normal Class B car licence, no colour vision test is required at all, and many drivers never take one. The test becomes relevant for the licence classes C and D, for lorries and buses, and in a small number of special cases. If you are not sure whether the test applies to you, this guide will give you the answer, and it will take away the worry that colour blindness means the end of your driving plans.

Do you need a colour vision test for Class B

The clear answer for most readers is no. The driving licence eye test for Class B checks only your visual acuity, which is how sharply you can see, and it does not include a test of your colour vision. That means you can apply for a car licence without ever being tested on colours, and a red-green colour weakness has no effect on your Class B application. Many people with a colour vision deficiency drive cars every day without any problem, because they recognise traffic lights by their position and brightness, not only by their colour.

This is different from the requirements for professional drivers. If you want a licence for a lorry or a bus, the law is stricter, and a colour vision test is part of the medical report. The reason is that professional drivers spend many hours on the road, often at night and in difficult conditions, and they have to react to colour signals quickly and reliably. You can read about the standard test in our guide to the eye test procedure, which explains what is checked for Class B.

What is checked in the colour vision test

The colour vision test checks whether you can distinguish between colours, and in particular whether you can tell red and green apart. That combination is important in road traffic, because traffic lights, tail lights and some road signs use red and green as their main signals. The test does not check whether you can see colours beautifully or name every shade of a rainbow. It checks whether your colour vision is good enough to use colour signals reliably in traffic.

Most colour vision deficiencies are inherited, and they affect men far more often than women. About eight per cent of men and less than one per cent of women have some form of red-green colour vision deficiency, and most of them have lived with it all their lives without noticing it in everyday situations. A colour vision deficiency is not a disease of the eye in the usual sense, and it does not get worse with age in the way that other eye problems can.

The Ishihara test: coloured dots that form numbers

The most common colour vision test uses the Ishihara plates. Each plate is a circle made of many coloured dots, and hidden inside the dots is a number. A person with normal colour vision can see the number clearly, while a person with a red-green deficiency either sees a different number or no number at all. You are shown several plates one after another, and the doctor or optician notes how many you get right. The test takes only a few minutes and it is painless.

There are also other tests that use coloured lights or arrange coloured caps in order, but the Ishihara plates are by far the most widely used, because they are quick, cheap and reliable. If the result is unclear, the examiner may repeat the test under different lighting conditions or use a second type of test to confirm the result. Good lighting matters, because poor light can make the colours look different and can change the result.

Red-green colour blindness: the most common form

Red-green colour blindness is the most common form of colour vision deficiency, and it is usually inherited. It does not mean that you see the world in black and white. People with this condition can see colours, but they have difficulty telling certain shades of red and green apart, especially when the colours are pale or mixed with brown, orange or grey. In everyday life this rarely causes problems, because most objects can also be recognised by their shape, brightness or position.

The condition is present from birth, and it does not change much over the years. It affects about eight per cent of men and less than one per cent of women, because the genes responsible are on the X chromosome. If you know that colour blindness runs in your family, you can have yourself tested before you start your driving licence training, so that you know where you stand and can plan accordingly.

Who must take the colour vision test

For the licence classes C and D, a colour vision test is part of the medical report. The doctor checks your colour vision together with your visual acuity, your visual field and your twilight vision, and all of these have to meet the higher standards for professional drivers. If a colour vision deficiency is found, the doctor has to decide whether it is mild enough to be compatible with professional driving or whether it is a reason to refuse the licence for those classes.

For Class B, there is no colour vision test, and a deficiency has no effect on your application. It is also possible that an ophthalmologist will test your colour vision if you are examined for another reason, for example because you had an eye operation or an eye disease. In that case, the result is noted in your medical record, but it does not affect your car licence.

What happens if you fail the colour vision test

Failing a colour vision test for the classes C and D does not automatically mean that you can never drive a lorry or a bus. The doctor will look at the degree of the deficiency and may carry out further tests to see exactly how much it affects your ability to recognise colour signals. Mild forms of red-green deficiency are often acceptable, especially if the rest of your vision is good. Only a severe deficiency is likely to be a reason to refuse the licence.

If you are told that you cannot get a Class C or D licence because of your colour vision, you can ask for a second opinion from another ophthalmologist, and you can ask the driving licence authority what the exact requirements are. For answers to other common questions, see our frequently asked questions page, where we answer the questions we hear most often about the eye test.

Can you drive with colour blindness

Yes, in almost all cases you can drive a car with colour blindness, because the Class B licence does not test colour vision. In practice, drivers with a red-green deficiency learn to use other clues: the position of the lights in a traffic light, the brightness of a signal, and the behaviour of the cars around them. Traffic lights in Germany are built in a fixed order, with red at the top and green at the bottom, so their position is a reliable guide even if the colours are hard to tell apart.

There are also special glasses and contact lenses that are marketed as helping colour blind people, but their effect in traffic is limited, and they are not accepted as a replacement for the medical requirements. The best advice is to be honest about your colour vision, to know your own limits, and to be extra careful in situations that depend on colour, such as a single flashing signal at night.

How the colour vision test is done at the optician

The colour vision test for the driving licence is usually done with a set of plates that show coloured dots in different shades, the so called Ishihara plates. Each plate contains a number or a shape that is made of dots in one colour, while the background is made of dots in a different colour. A person with normal colour vision can see the number clearly, while a person with a red green deficiency sees a different number or no number at all. The test is done in daylight or under a special lamp, and it takes only a few minutes. The optician shows you several plates in a row, and you simply say what you can see on each one. There is no pain and no preparation, and you do not have to study anything in advance.

In some cases the optician also uses a different device, called an anomaloscope, which shows two fields of colour that you have to match by turning a knob. This test is more precise and is mainly used by ophthalmologists when the result of the plates is not clear. A lantern test is another option, in which small coloured lights are shown and you have to name their colour. For most driving licence applicants, the plates are enough, because the question is only whether you can distinguish red and green reliably. The result is noted on your certificate or in the report, and if the result is unclear, you may be sent to an ophthalmologist for a more detailed examination.

Your checklist for the colour vision test

The colour vision test is only a small part of the eye test for most licences, but it is worth knowing what to expect. This checklist covers the test itself, what happens if you have a colour vision deficiency, and when the test matters for your licence.

• Ask in advance whether a colour vision test is part of your eye test, because it is not always included for a Class B licence.
• Be ready for the Ishihara plates, which show coloured dots that form a number, and say the number that you see.
• Do the test in good light, because poor lighting can make the colours harder to tell apart.
• Wear your usual glasses or contact lenses, because the test is done with your normal correction.
• Tell the optician if you know that you have a colour vision deficiency, so that the result is recorded correctly.
• If the result is unclear, the optician may repeat the test or use a different method, such as a lantern test.
• Remember that a colour vision deficiency does not stop you from getting a Class B licence in most cases.
• If you apply for a lorry or bus licence, ask about the stricter colour vision rules before you book the medical report.
• Keep the result with your other documents, because the driving licence authority may ask for it for a professional licence.

Conclusion

The colour vision test for the driving licence is a small part of the whole process, and for most people it does not apply at all. For a Class B car licence, no colour vision test is required, and a red-green colour weakness is no obstacle to driving. For the licence classes C and D, the test is part of the medical report, and a mild deficiency is often still acceptable. If you are not sure about your own colour vision, a quick Ishihara test at an optician or a doctor gives you clarity in a few minutes, so that you can plan your driving licence training with confidence.

Frequently asked questions

Is a colour vision test required for a Class B driving licence?

No. The eye test for Class B checks only your visual acuity. Colour vision is not part of the standard test.

What is the Ishihara test?

It is a test with coloured dots that form numbers. People with normal colour vision can see the numbers, while people with a red-green deficiency see different numbers or no number at all.

How common is red-green colour blindness?

About eight per cent of men and less than one per cent of women have some form of red-green colour vision deficiency. It is usually inherited and present from birth.

Can I drive a lorry or a bus with colour blindness?

It depends on how strong the deficiency is. Mild forms are often acceptable, but a severe deficiency can be a reason to refuse a Class C or D licence.

Can I drive a car with colour blindness?

Yes. Colour vision is not tested for a Class B licence, and drivers with colour blindness use the position and brightness of traffic lights as reliable clues.

Are special glasses for colour blindness helpful?

Their effect in traffic is limited, and they are not accepted as a replacement for the medical requirements for professional driving licences.

Do I need a colour vision test for a Class B driving licence?

No, a colour vision test is not part of the standard eye test for Class B. The standard test only measures your visual acuity and checks your visual field. A colour vision test is usually only needed for professional licences such as Class C and Class D, where the requirements are stricter. If you are not sure whether you have a colour vision deficiency, you can still ask the optician for a separate test, but it is not required for a normal car licence.

Can I fail the driving licence eye test because of colour blindness?

For a Class B licence, no, because colour vision is not part of the standard test. For Class C and Class D, a severe red green deficiency can be a problem, but many people with a mild deficiency still pass, because the test checks whether you can recognise the colours of traffic lights reliably. The decision is made by the ophthalmologist who writes the report, and they look at the degree of the deficiency and the requirements of the licence class.