Farbtests

Farbtests are assessments used to evaluate color vision and color perception. They are applied in ophthalmology, neurology, psychology, and occupational screening to detect color vision deficiencies and to measure color discrimination abilities. The tests vary in complexity, purpose, and what aspect of color vision they probe.

Among the most widely known is the Ishihara test, designed to screen for red–green deficiencies. It uses plates with colored dots forming numbers or paths that are visible to those with normal color vision but hidden to many with color deficiencies. Other commonly used tests include the Farnsworth–Munsell 100 Hue Test and the Farnsworth D-15/D-10 series, which require arranging colored caps in order and yield a quantitative error score. Computer-based tests such as the Cambridge Color Test measure color discrimination thresholds in a controlled color space. The Nagel anomaloscope offers precise matching of red and green wavelengths and is used to diagnose anomalous trichromacy. The Farnsworth Lantern serves as a practical screening tool for aviation and maritime settings where color signals are critical.

Administration typically occurs under standardized lighting, with results compared to normative data. Tests can indicate the type of deficiency (e.g., red–green versus blue–yellow) and, for some methods, estimate severity. Limitations include variable sensitivity, potential miss of subtler deficiencies, and influences from age, media opacity, or testing illumination. Consequently, color tests are used as screening tools or part of a broader clinical assessment rather than definitive diagnoses on their own. See also color vision deficiency and related diagnostic instruments.