Farnsworth Lantern Test (FALANT)

What is the Farnsworth Lantern Test?

The FALANT was created by Dean Farnsworth — the same Navy researcher behind the D-15 arrangement test — to answer a practical wartime question: can this sailor read signal lights at sea? The apparatus shows two small lights stacked vertically, each red, green, or white, viewed from across a room. The examinee names both colors, nine pairs per run. There is no hidden number and no arrangement puzzle; it is exactly the task the job requires, miniaturized.

That job-realism is the point. The colors and intensities were chosen to mimic shipboard signal lights at distance, and white is included precisely because desaturated reds and greens are what people with red-green deficiencies most often confuse with it. Scoring is simple: name all nine pairs correctly on the first run and you pass; make errors and the test is repeated, with the average of later runs deciding the result.

Why the FALANT deliberately passes mild color deficiency

Clinical tests like Ishihara are built to catch every deficiency, however mild. The FALANT was built to a different specification: screen out people who would actually misread signal lights, and pass everyone else — including mild anomalous trichromats whose color discrimination is reduced but still good enough for the task. Studies over the decades put the share of color-deficient people who pass the FALANT at roughly 30%, which is not a flaw but the design goal.

This is the key fact for interpreting a FALANT result in either direction. Passing the FALANT does not mean your color vision is clinically normal — it means it was judged operationally adequate for signal recognition. Failing Ishihara but passing a lantern test was, for decades, exactly the path by which mildly color-deficient people entered maritime, rail, and aviation careers.

Where the FALANT stands now

The original Macbeth-built lanterns are long out of production, and successor devices carried the concept forward — the OPTEC 900 series is the FALANT-equivalent commonly cited in US military and Coast Guard contexts, and other countries use their own lanterns, such as the Holmes-Wright in UK maritime licensing. Availability of working, calibrated units has become a real constraint: fewer clinics keep one, and appointments can be hard to find.

The clearest regulatory shift came from the FAA: effective January 1, 2025, pilot color vision screening moved to three approved computer-based tests (CAD, Rabin Cone Contrast, Waggoner CCVT), administered in person — and lantern tests are no longer on the acceptable list. Pilots who passed a FALANT or other lantern test at an earlier FAA medical are grandfathered. Military services and some maritime authorities continue to use lantern-type or cone-contrast testing under their own rules, so the FALANT's operational philosophy survives even where the original hardware is retired.

Can you take the Farnsworth Lantern Test online?

No — and this one genuinely cannot be simulated on a consumer screen. The FALANT's validity depends on small, precisely calibrated light stimuli of controlled luminance and chromaticity, viewed at a set distance in controlled lighting. A phone or monitor cannot reproduce a point light source of known intensity, and a web page claiming to be an online FALANT is a lookalike, not the test. If a lantern result matters for your career, it has to come from a working, calibrated device administered in person.

What a browser screening can honestly do is tell you the underlying variables: whether a red-green deficiency is likely, whether it leans protan or deutan, and roughly how strong it is. A mild result is precisely the profile that historically passed lantern tests, and a strong result means signal-light color naming is likely to be affected — useful information to have before booking any occupational test.

Farnsworth Lantern Test — frequently asked questions

What is a passing score on the FALANT?

Naming all nine light pairs correctly on the first run is a pass. If errors occur, the test is repeated and the average error count across the later runs decides the result — the pass criterion is an average of one error or fewer across those runs, per the original Navy protocol.

Can color blind people pass the Farnsworth Lantern Test?

Mildly color-deficient people often can — studies put the pass rate among anomalous trichromats at roughly 30%. That is by design: the FALANT is an operational aptitude test for signal-light recognition, not a clinical screen, so it intentionally passes deficiencies mild enough not to affect the task. Strong protan or deutan deficiencies are reliably caught.

Does the FAA still accept the Farnsworth Lantern Test?

No. Effective January 1, 2025 the FAA accepts only three computer-based tests (CAD, Rabin Cone Contrast Test, Waggoner CCVT), administered in person, and lantern tests are no longer on the approved list. Pilots who passed a FALANT at a previous FAA medical are grandfathered and do not retest.

Is the FALANT still used by the military?

Lantern-style and cone-contrast testing continue in military and maritime settings under each service's own rules — the OPTEC 900 is the commonly cited FALANT-equivalent in US Navy and Coast Guard contexts, and the Rabin Cone Contrast Test is used across US services. Requirements vary by service and role, so the applicable instruction, not this page, is authoritative.

Is there an online version of the FALANT?

No. The test requires calibrated point-light stimuli at controlled intensity, distance, and ambient lighting — none of which a consumer screen can reproduce. Online lantern tests are lookalikes. A browser screening can estimate the underlying deficiency type and severity, which is useful preparation, but it is not a FALANT result.

What is the difference between the FALANT and the Farnsworth D-15?

Same author, different tools. The D-15 is a clinical arrangement test — order 15 colored caps by hue — that classifies the type and axis of a deficiency. The FALANT is an occupational signal-light test that asks one practical question: can you name red, green, and white lights reliably at distance? A person can fail Ishihara, show a mild axis on the D-15, and still pass the FALANT.