The Farnsworth D-15 Color Vision Test is a clinically recognized screening tool used to evaluate color discrimination. This online version recreates the classic arrangement test with interactive drag-and-drop discs, detailed scoring metrics, and automated interpretation. It is designed for people who suspect color vision difficulties, students in vision sciences, or anyone interested in understanding their perception of color axes such as protan, deutan, and tritan. It’s free, no registration or e-mail needed.
How to use the test
- Sit in front of your screen under neutral lighting without blue-light filters or night mode enabled.
- Identify the fixed reference disc, which anchors the sequence.
- Drag the colored discs from the pool and arrange them in a smooth hue order around the circle.
- You can swap discs already placed by dragging them back or moving them into another slot.
- When all discs are arranged, press “Score” to receive results.
- Interpretation: a smooth sequence with minimal errors indicates normal vision, while misplacements or large jumps reveal patterns of protan, deutan, or tritan color deficiency.
Features of the test
- Full set of 15 movable discs plus a fixed reference disc, matching the original Farnsworth design.
- Interactive drag-and-drop interface with slot highlights, swap functionality, and double-click/tap placement – just press the circle twice and it will go to the next empty spot.
- Automatic scoring using TES (Total Error Score), CCI (Color Confusion Index), permutation error, maximum and mean jump size.
- Axis analysis identifies whether confusion aligns with protan (red), deutan (green), or tritan (blue-yellow) lines.
- Results include a headline classification (Normal, Mild defect, Moderate/Severe defect, Questionable), numerical metrics, and time taken.
- Side-by-side visual comparison of your sequence with the ideal arrangement.
- Recommendations provided based on the severity and axis of detected confusion.
Understanding color vision axes
Human vision relies on three cone types sensitive to long (L), medium (M), and short (S) wavelengths. Defects in L-cones create protan deficiencies (red-weak), M-cone defects cause deutan deficiencies (green-weak), and S-cone issues lead to tritan deficiencies (blue-yellow confusion). The Farnsworth D-15 test is designed to expose these confusion axes by requiring discs to be ordered in a perceptually uniform hue circle. Misplacements reveal where discrimination breaks down.
- Protan defects shift sensitivity to reds and can affect recognition of traffic signals or safety labels.
- Deutan defects reduce green discrimination, common in hereditary color blindness.
- Tritan defects are rare, often acquired with age or eye disease, and impact blue-yellow perception.
FAQ
- What is the Farnsworth D-15 test? – A standardized color vision test using 15 colored discs to detect major types of color vision loss.
- How accurate is the online version? – It closely replicates the principles, but display calibration and lighting can influence results.
- Can this test diagnose color blindness? – It classifies patterns and severity but cannot replace a clinical diagnosis.
- What do the metrics TES and CCI mean? – TES shows total error magnitude, while CCI compares results against expected thresholds.
- What is a confusion axis? – The direction of errors in color space, revealing protan, deutan, or tritan deficiencies.
- Who should take the test? – Anyone with suspected vision issues, students in vision sciences, or professionals in safety-critical tasks.
- How long does the test take? – Usually between 3 and 6 minutes, depending on user speed.
Sources and references
- American Academy of Ophthalmology – Color Blindness
- National Center for Biotechnology Information – Inherited Color Vision Deficiency
- Official Farnsworth-Munsell
What’s your results in this test? Would you like to see any more features in it? Let us know in the comments below!
CalcuLife.com
Leave A Comment