Office of Aerospace Medicine Technical Reports
FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-78/22
Title and Subtitle: Aeromedical implications of the X-Chrom lens for improving color vision deficiencies
Report Date: April 1978
Authors: Welsh KW, Vaughan JA, Rasmussen PG
Abstract: The X-Chrom contact lens is a recent device recommended to improve defective color vision. The red lens is usually worn on the nondominant eye and may require extended wearing for optimum color vision enhancement. A battery of tests was given to 24 individuals, 12 with normal and 12 with defective color vision. A mix was made between standard clinical color vision tests, spectral signal light tests, and visual/oculomotor performance tests.
Between the first and second evaluations (approximately 7 weeks), individuals with defective color vision wore X-Chrom contact lenses for 6 hours each day. While wearing X-Chrom lenses, subjects had significantly improved scores on standard clinical pseudoisochromatic plate tests, including the Hardy-Rand-Rittler, Ishihara, and Dvorine plates.
Our data indicated that color identification scores using the Farnsworth Lantern, Color Threshold Tester, and the Aviation Signal Light Gun were not significantly different for evaluations made with and without the X-Chrom lens. Minimal changes were found on several tests including the Farnsworth D-15, aeronautical chart color identification task, Holmgren Yarn, visual acuity, phorias, and stereoscopic depth perception. The majority of control and experimental subjects noted a change in the perceived path of the swinging pendulum (Pulfrich test) while viewing through a monocular red filter or an X-Chrom lens, respectively.
Key Words: Color vistion, X-Chrom lens, Signal lights, Aviation safety
No. of Pages: 21
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-78/22
Title and Subtitle: Aeromedical implications of the X-Chrom lens for improving color vision deficiencies
Report Date: April 1978
Authors: Welsh KW, Vaughan JA, Rasmussen PG
Abstract: The X-Chrom contact lens is a recent device recommended to improve defective color vision. The red lens is usually worn on the nondominant eye and may require extended wearing for optimum color vision enhancement. A battery of tests was given to 24 individuals, 12 with normal and 12 with defective color vision. A mix was made between standard clinical color vision tests, spectral signal light tests, and visual/oculomotor performance tests.
Between the first and second evaluations (approximately 7 weeks), individuals with defective color vision wore X-Chrom contact lenses for 6 hours each day. While wearing X-Chrom lenses, subjects had significantly improved scores on standard clinical pseudoisochromatic plate tests, including the Hardy-Rand-Rittler, Ishihara, and Dvorine plates.
Our data indicated that color identification scores using the Farnsworth Lantern, Color Threshold Tester, and the Aviation Signal Light Gun were not significantly different for evaluations made with and without the X-Chrom lens. Minimal changes were found on several tests including the Farnsworth D-15, aeronautical chart color identification task, Holmgren Yarn, visual acuity, phorias, and stereoscopic depth perception. The majority of control and experimental subjects noted a change in the perceived path of the swinging pendulum (Pulfrich test) while viewing through a monocular red filter or an X-Chrom lens, respectively.
Key Words: Color vistion, X-Chrom lens, Signal lights, Aviation safety
No. of Pages: 21
Last updated: Friday, June 1, 2012