Farnsworth Lantern Test (FALANT)

The signal-light color vision test used by the U.S. Navy, Coast Guard, FAA, and maritime services since 1954. Identify pairs of colored lights to assess your ability to distinguish navigation signals.

Farnsworth Lantern Test (FALANT)

Identify pairs of colored signal lights, just like the clinical test used by the U.S. Navy, FAA, and military since 1954.

9 pairs of lights shown for 3 seconds each
Identify the top and bottom colors: Red, Green, or Yellow
Trust your first impression — don't overthink

What is the Farnsworth Lantern Test?

The Farnsworth Lantern Test (FALANT) was developed by Commander Dean Farnsworth at the Naval Submarine Medical Research Laboratory in New London, Connecticut. First introduced in 1954, it became the standard color vision test for the U.S. Navy and has since been adopted by the U.S. Coast Guard, Federal Aviation Administration (FAA), and merchant marine services.

Unlike plate-based tests such as the Ishihara, the FALANT uses vertically paired signal lights (red, green, and white) to simulate real-world conditions faced by pilots, sailors, and signalmen. Each pair is shown briefly through a small aperture, mimicking a distant signal light. The test subject must identify both the top and bottom colors.

The FALANT is designed to pass individuals with mild color deficiency who can still perform safety-critical tasks, while screening out those with moderate to severe impairment. Approximately 30% of people who fail Ishihara plate tests can pass the FALANT, making it an important alternative pathway for aviation and maritime careers.

How to Take the Test

1. Observe the Lights

Two colored lights appear vertically for 3 seconds. Pay close attention to both the top and bottom colors before they disappear.

2. Select Colors

After the lights disappear, choose the color you saw for each light: Red, Green, or Yellow. Trust your first impression — the clinical test does not allow second guesses.

3. Complete All 9 Pairs

The test presents 9 randomized light pairs — every possible combination of red, green, and yellow. Your score determines your color vision classification.

Clinical FALANT vs. This Online Version

The original clinical FALANT uses a specialized instrument with calibrated optical filters to produce precise red, green, and white lights viewed through a narrow aperture at a set distance. Our online version adapts the core methodology with the following differences:

Clinical FALANT

- Calibrated optical instrument
- Viewed at 8 feet (2.4 m) distance
- Small aperture simulates distant signals
- Uses true white light (incandescent)
- Administered in controlled dark room

This Online Version

- Screen-based simulation
- Normal viewing distance
- Larger light display on screen
- Yellow substituted for white (screen limitation)
- Results vary with screen calibration

Note: This online test is a screening tool and cannot replace an official FALANT examination. If you require a certified result for employment or licensing, consult a qualified optometrist or occupational health professional.

History and Real-World Impact

Commander Dean Farnsworth developed the lantern test in response to the Navy's need for a practical, real-world assessment of color vision. Traditional plate tests were overly strict — they failed many individuals who could, in practice, safely identify navigation signal lights. The FALANT was designed to test functional color vision rather than theoretical color discrimination.

The test was adopted by the U.S. Navy as the primary color vision test and later by the U.S. Coast Guard, Federal Aviation Administration (FAA), and various merchant marine authorities worldwide. It served as the military standard for nearly four decades.

In 1993, the U.S. Air Force discontinued the FALANT in favor of the Cone Contrast Test (CCT), which uses a computer monitor to assess individual cone function. However, the FALANT remains in active use by naval and maritime services as a secondary or alternative test.

The importance of accurate color vision screening was underscored by the FedEx Flight 1478 crash on July 26, 2002. The first officer, who had a known color vision deficiency, failed to correctly identify approach lighting. The NTSB investigation cited the crew's failure to properly identify visual signals during the non-precision approach. This incident reinforced why aviation authorities maintain strict color vision standards.

Understanding Your Score

8-9 Correct — Normal Vision

You can reliably distinguish red, green, and yellow signal lights. This score would pass the clinical FALANT and qualify for aviation, naval, and maritime duties.

6-7 Correct — Mild Deficiency

You may have difficulty with some color combinations. In the clinical setting, a second test run is typically offered. Some positions may still accept this result.

4-5 Correct — Moderate Deficiency

Significant difficulty identifying signal-light colors. This would not pass the clinical FALANT for safety-critical roles.

0-3 Correct — Strong Deficiency

Major difficulty distinguishing signal lights. This indicates a significant color vision deficiency that would affect safety-critical tasks involving colored signals.

Sources

Farnsworth Lantern Test — Wikipedia — Overview of the FALANT, its development, and clinical use
FAA Guide for Aviation Medical Examiners — Color Vision — FAA's accepted color vision testing methods including FALANT
National Eye Institute (NEI) — Overview of color blindness types, causes, and diagnosis
NTSB Accident Report AAR-03/02 — FedEx Flight 1478 investigation highlighting color vision in aviation safety
PubMed — National Library of Medicine — Peer-reviewed research on occupational color vision testing

Frequently Asked Questions

The Farnsworth Lantern Test (FALANT) is used by the U.S. Navy, Coast Guard, FAA, and merchant marine to screen color vision for safety-critical roles. It tests the ability to correctly identify colored signal lights — red, green, and white — which are essential for navigation, aviation, and maritime operations.

Yes. Approximately 30% of people who fail the Ishihara plate test can pass the FALANT. The lantern test evaluates practical ability to identify signal lights rather than fine color discrimination, so individuals with mild color deficiency may still pass.

In the clinical setting, you must correctly identify at least 9 out of 9 pairs in one of two runs. If you score below 9 on the first run, a second run is given. Our online version uses a scoring scale: 8-9 correct indicates normal vision, 6-7 mild deficiency, 4-5 moderate, and 0-3 strong deficiency.

Computer screens cannot produce the same white light used in the clinical FALANT instrument, which uses incandescent bulbs behind calibrated filters. Yellow is used as a screen-compatible substitute. In the clinical test, white is the hardest color to identify correctly and is most often confused with green by color-deficient individuals.

No. Both were developed by Dean Farnsworth, but they test different things. The Lantern Test (FALANT) evaluates your ability to identify signal-light colors for occupational screening. The Farnsworth-Munsell 100 Hue Test measures fine color discrimination by having you arrange colored caps in order. They serve different clinical purposes.

No. This online version is a screening tool only. Official certification requires an in-person examination using calibrated equipment administered by an authorized medical examiner. If you need a certified result, contact an Aviation Medical Examiner (AME) or military optometrist.