Farnsworth Lantern Test (FALANT)

What the lantern test is

Developed by the US Navy in the 1940s, the FALANT shows pairs of small coloured lights, red, green and white, which you name aloud. Unlike the Ishihara plates, it isn't designed to diagnose the type of colour deficiency. It's an occupational test: it checks whether, in practice, you can reliably identify signal colours. Some people with a mild red-green deficiency still pass, because the task tolerates mild anomalies.

Who has to take it

Colour-signal safety roles, including:

• Aviation: pilots and some air-traffic roles, where signal lights and cockpit indicators matter.
• Maritime: deck officers and mariners reading navigation lights at sea.
• Rail: drivers and signallers who depend on coloured lineside signals.
• Military: many roles with colour-coded equipment and signals.

Exact standards vary by country and authority (for example, the FAA, national maritime bodies, and rail regulators each set their own rules), and the FALANT is only one of several accepted tests.

The pass standard

Broadly, you're shown a series of light pairs and must name them with very few errors. Because the specific pass criteria and permitted retests depend on the authority and the year, always check the current medical standard for the licence you're pursuing rather than relying on general descriptions.

Can you practise it online?

Not faithfully. The FALANT depends on calibrated coloured light sources at a set distance and brightness, which a computer or phone screen can't reproduce. What you can do online is a useful pre-check: if you clearly fail a red-green screen, you're likely to struggle with a lantern test, and it's worth knowing before an official medical.

How to prepare

• Take an honest colour vision screen and the red-green test first, so there are no surprises.
• Be well-rested and take the official test in good conditions; fatigue and glare hurt performance.
• Don't rely on colour-blind glasses, most colour-vision medicals are taken without them.
• If you're borderline, ask the examiner which alternative tests the authority accepts.