Related Experiment Video
Updated: Apr 7, 2026
09:29
A Standardized Obstacle Course for Assessment of Visual Function in Ultra Low Vision and Artificial Vision
Published on: February 11, 2014
13.6K
A lantern color vision test for the rail industry
1School of Optometry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada. jhovis@uwaterloo.ca
American Journal of Industrial Medicine
|November 9, 2000
Summary
A new lantern test effectively assesses rail signal color identification, proving more occupationally relevant than standard screening. It accurately identifies individuals with color vision defects, crucial for railway safety.
Area of Science:
- Ophthalmology
- Occupational Health
- Transportation Safety
Background:
- Accurate wayside signal color identification is vital for railway operational safety.
- Standard color vision screening tests may lack occupational relevance for rail industry roles.
Purpose of the Study:
- To develop and validate a functional color vision test for the rail industry.
- To assess the occupational relevance of color discrimination in railway signal identification.
Main Methods:
- A novel lantern test (CNLAN) was created for functional color assessment.
- The CNLAN was validated against a simulated field trial.
- Participants included 81 individuals with normal color vision and 74 with red-green defects, classified using a Nagel Anomaloscope.
Main Results:
- 97% of individuals with color vision defects failed both the CNLAN and simulation trial.
- The CNLAN demonstrated higher specificity than the Ishihara test, correctly passing all color-normal individuals.
- The Ishihara test incorrectly failed 3.7% of color-normal individuals who passed the simulation and lantern tests.
Conclusions:
- The developed lantern test offers a practical functional assessment for identifying rail signal colors.
- Applying a strict failing criterion enhances the test's effectiveness for screening.
- This test is particularly valuable for ensuring the occupational suitability of personnel in the rail industry.
Related Concept Videos
01:22Photoreceptors and Visual Pathways
11.1K
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category,...
11.1K
01:24Color Vision
1.9K
Color perception begins in the retina, the light-sensitive layer at the back of the eye. Two main theories explain how colors are seen: the trichromatic theory and the opponent-process theory. The trichromatic theory, proposed by Thomas Young in 1802 and extended by Hermann von Helmholtz in 1852, suggests that color vision is based on three types of cone receptors in the retina. These cones are sensitive to different but overlapping ranges of wavelengths corresponding to red, blue, and green.
1.9K
01:28Survey Safety
486
Surveying near highways, rough terrain, or power lines involves significant risks. Working along highways is particularly dangerous and requires the use of warning signs and flagmen. It is safest to avoid working directly on roads and use offsets whenever possible. When highway work is unavoidable, it must follow all safety guidelines. Surveyors should wear bright clothing, such as orange reflective vests, to ensure visibility to motorists, coworkers, and hunters. In construction zones, wearing...
486