The Farnsworth Lantern Test (FALANT) is one of the more forgiving color vision tests for people with mild color deficiency, but passing it requires knowing exactly what to expect and how the scoring works. You need to correctly name 9 out of 9 color pairs on your first attempt, or score at least 16 out of 18 on a second series if you miss any on the first round. Here’s what the test involves and how to give yourself the best chance.
How the Test Works
The test shows you pairs of colored lights, one on top and one on bottom. The only three colors used are red, green, and white. You’ll see them in various two-light combinations, including pairs of the same color. Each pair appears for about 2 seconds, and you call out the top color first, then the bottom.
You’re told upfront that the only possible answers are red, green, or white. If you call out “yellow,” “pink,” or any other color, the examiner will remind you to choose only from those three options. That reminder itself is actually useful information: the white light can look yellowish or pinkish depending on your color vision, so knowing the answer has to be “white” helps you categorize what you’re seeing.
The first series is 9 pairs. Get all 9 correct and you pass immediately. Miss even one, and you move to a second series of 18 pairs. On that second round, you need at least 16 correct to pass. There is no third chance.
Why People Fail
Color-deficient test takers tend to make two specific types of errors. The first involves the white light. When white appears next to red, people with red-green deficiency often call the white light “green.” When white appears next to green, they call it “red.” Essentially, the brain interprets white as the complement of whatever color is beside it. Recognizing this tendency in yourself is the single most useful thing you can do before test day.
The second common error happens when two lights of the same color appear together but at different brightness levels. The test deliberately presents some pairs where one light is 50% brighter than the other. A bright green next to a dim green, for example, can look like “white and green” to someone with color deficiency. Knowing that same-color pairs with different brightness exist in the test helps you avoid jumping to “white” when you see a brighter light.
Preparation That Actually Helps
You can’t change your color vision, but you can optimize the conditions around it. The most practical strategies involve managing your eyes and your environment before the test.
Rest your eyes beforehand. Spending hours in front of screens or under harsh artificial lighting can shift your color perception. Fluorescent office lighting, which skews toward the blue end of the spectrum, is particularly problematic for people with red deficiency. Some test takers report that spending time outdoors in natural daylight before the exam helps their eyes calibrate.
The test itself is supposed to be administered under specific lighting conditions, around 5500K color temperature, which mimics daylight. In practice, many offices use standard fluorescent tubes that don’t meet this standard. If you’re taking the test at an optometrist’s office or military facility, you can politely ask whether the room lighting meets the test specifications. An improperly lit room can make the difference between passing and failing for someone on the borderline.
Practice the mental framework before you walk in. You only have three choices: red, green, white. Train yourself to think in those categories. If a light looks ambiguous, ask yourself whether it has a clear hue or looks washed out. Washed out, pale, or warm-toned lights that don’t look distinctly red or green are almost certainly the white stimulus.
Color-Correcting Lenses Are Not Allowed
Products like X-Chrom or EnChroma lenses are explicitly prohibited during official color vision testing for both FAA and Coast Guard purposes. The regulations specify that color-sensing lenses cannot be used. Don’t plan around them.
Where the FALANT Is Still Used
The FALANT’s role has narrowed over the years, so it matters which career path you’re pursuing.
For U.S. military service, the Navy accepts the FALANT or the Optec 900 (a modern device that uses the same test protocol). The original FALANT hardware is no longer manufactured, so most military testing facilities use the Optec 900 instead. Despite the different hardware, pass/fail levels between the two are comparable.
For merchant mariners, the U.S. Coast Guard lists the Farnsworth Lantern as an accepted color vision test for deck officer credentials. It’s one of several options alongside the Ishihara plates and the Farnsworth D-15 Hue Test.
For pilots, the landscape changed significantly in January 2025. The FAA now requires approved computer-based color vision screening tests, and any test not specifically listed is no longer acceptable. If you’re pursuing an FAA medical certificate, confirm with your Aviation Medical Examiner which tests currently qualify before scheduling anything.
Finding a Test Location
Because the original lantern is out of production, finding a facility that has one (or an Optec 900) takes some effort. University optometry schools are among the most reliable sources. The University of Houston College of Optometry and SUNY College of Optometry in Manhattan have both been used by applicants seeking the test.
For aviation purposes, FAA regional offices and Flight Standards District Offices (FSDOs) can direct you to providers. One important limitation: the FAA will only allow you to take the FALANT once through their own offices. After that, you need to find a private practitioner or pursue a different qualifying test, such as the Signal Light Gun Test.
Call ahead to confirm the facility still has working equipment and can administer the test under proper conditions. A wasted trip to a clinic with a broken or retired device is more common than you’d expect.
What to Do on Test Day
Arrive with well-rested eyes. Avoid prolonged screen time for at least a couple of hours beforehand. If you wear corrective lenses for distance, bring them, as the test is administered at 8 feet and you need to see the lights clearly.
When the test begins, respond quickly but don’t rush. You have about 2 seconds per pair. Call the top light first, then the bottom. Stick to the three-word vocabulary: red, green, white. If something looks ambiguous, lean toward “white” rather than inventing a color that isn’t one of the options.
If you miss one in the first series of 9, don’t panic. The second series of 18 gives you room for up to 2 errors. Many people with mild color deficiency pass on the second round. Stay focused and apply what you noticed from the first series. If you caught yourself confusing white with green, for instance, use that awareness to adjust.
The FALANT was specifically designed to identify people whose color deficiency is mild enough that they can still reliably distinguish signal lights in real-world conditions. About 30% of people who fail the Ishihara plates can pass the FALANT. If your deficiency is moderate to severe, the test may simply be beyond what preparation can overcome, and pursuing an alternative pathway like the Signal Light Gun Test for aviation or the D-15 for maritime engineering roles may be a more productive route.