Everything You Need to Know About Red-Green Colour Deficiency Tests for Marine Certification
Most people with colour vision deficiency working in industries, such as marine industries, have to face great challenges if their condition is not improved because colour cues are frequently used.
Many marine certification roles require the ability to spot colours very vividly, and accurately telling colours is very important to ensure safe navigation, signalling, and more.
This blog takes a deep dive into the essentials of red green colour deficiency test for marine certification from test types, to their accuracy, and all this has meant for certification.
Why Do Marines Need Colour Vision?
Colour vision is fundamentally essential in marine roles for many reasons :
- Navi channel markers and safety colours: Normally, port and starboard navigation lights are two different colours, and buoys also use channel markers. Identifying all of these colours is indispensable in preventing collisions and ensuring safe navigation.
- Emergency indicators and equipment labels: Emergency equipment and controls are usually colour-coded. Misidentifying these colours can sometimes mean unwanted delay or inappropriate action at critical times.
- Another method of communication used by mariners is colour-coded signals that are not only used onboard but also when communicating with other vessels or port authorities.
Types of Red-Green Colour Deficiency Tests for Marine Certification
Ishihara Test: The most common red green colour deficiency test used is the Ishihara Test. With the test, individuals must read numbers or follow paths on a set of plates filled with dots. In this setup, the dots are arranged in forms that people suffering from red-green colour deficiency tend to miss.
- Pros: Easy to use, valid for diagnosing mild to severe red-green deficiency.
- Cons: Cannot identify cases of mild deficiency and no measuring scale can determine the deficiency.
Anomaloscope: The anomaloscope is a gold standard for diagnosing red-green colour vision deficiency. In this technique, the person has to adjust the intensities of red and green lights so that these two colours blend perfectly.
- Pros: Very precise and measurable in terms of the extent of deficiency.
- Cons: Equipment is expensive, and requires a small number of trained individuals for conducting the test.
Farnsworth Lantern Test: This is intended for operations where red, green, and white light identification is required in maritime, military, or aviation use. In this test, the individual must identify consecutive pairs of lights that may be presented in a random sequence.
- Pros: Tests the recognition of red and green lights used in navigation directly.
- Cons: Will not notice tiny defects, but this will be enough for concrete examination purposes.
Validity of Red-Green Colour Deficiency Tests
- Ishihara Test: It has a very high sensitivity to actually diagnose approximately 90% to 95% of most cases of red-green colour vision deficiency. However, lighting and other problems in the test plates.
- Anomaloscope Test: It is very sensitive, especially under controlled conditions. It may be up to 99% sensitive. It measures the deficiency level, and this stands to be very vital for dangerous professions such as in the maritime or military.
- Farnsworth Lantern Test Accuracy: While not as sensitive as the anomaloscope, it is much closer to real-life conditions. Thus, it is particularly useful for the certification needs of mariners. It is quite practical in detecting severe and moderate deficiencies.
Certification Process for Mariners with CVD
If a marine role applicant develops some degree of red-green colour vision deficiency, then his or her certification process may vary depending on the severity and considering the specific needs of the role:
- Minor deficiency: The minor maritime authorities will issue their certificate to those candidates with minor deficiencies, provided they pass the tests undertaken to simulate real-life situations in distinguishing between red and green lights, such as the Farnsworth Lantern Test.
- Major deficiency: The certification will still be issued to the candidates with greater deficiencies but limited to specific positions, which would usually involve navigation and emergency operations.
Policies differ from one country and organization to another, so applicants are advised to consult the relevant maritime authority or certification board in their region of origin to understand the specific requirements and allowances for CVD.
Inclusive Companies with Inclusive Practices Towards Colour Vision Deficiency
Some organizations are beginning to develop inclusive practices in the workplace for employees with colour vision deficiencies, noticing the hindrances that CVD may create. This ranges from adopting a system of using symbols or text in addition to colour coding for critical signals, to even providing aids such as colour vision deficiency glasses.
One example is Maersk, one of the world’s biggest shipping companies. The Royal Navy in the UK, too, has directives allowing personnel who fail the colour vision test to be accommodated in non-navigational occupations.
Conclusion
A large component of marine certification entails tests for red-green colour deficiency for those whose roles depend on accurate colour perception. Even though various tests exist, the Ishihara Test, anomaloscope, and Farnsworth Lantern Test are among those most recognized by the industry.
Colour blindness can impact people in the maritime industry because they may need to see colours correctly to identify lights, signals, symbols, and maps. If companies subsidize effective colour blindness glasses for individuals found with such issues, overall productivity can be significantly increased. Companies like COLORON’s offer advanced designs and hi-tech colour blindness glasses for red and green colour vision deficiency.
By filtering specific wavelengths, COLORON’s lenses amplify red-green colour signals, helping employees with colour vision deficiencies see distinctions more clearly. This enhanced colour perception reduces errors, improves safety, and boosts productivity, particularly in roles relying on colour-coded tasks. With decades of research behind their technology, COLORON offers an affordable way for companies to support an inclusive and visually accessible work environment for all.
