Side effects

The retina in the back of the eye contains two light-detecting cells called photoreceptors. The photoreceptors convert light into electrical signals sent to the brain via the optic nerve. These light-detecting cells are the rods and cones. Rods are highly sensitive to light and are responsible for night vision and peripheral vision. Cones detect red, green, and blue light. Red-sensing cones make up about 60 percent of cones. Green-sensing cones make up about 30 percent of cones, and blue-sensing cones make up about 10 percent of cones. People with protanopia cannot perceive red light, those with deuteranopia cannot perceive green light, and those with tritanopia cannot perceive blue light.

Color vision deficiency is inherited and primarily seen in males. Females are carriers of the color-blindness gene. Any abnormalities of the retina, optic nerve, and visual cortex in the brain can cause defects in color vision. Diseases like diabetes, glaucoma, and cataracts can alter color vision.  

Color-blindness in aviation is a significant issue because of our reliance to perceive red, green, and blue hues. Pilots rely on identifying navigation lights, aircraft position lights, airport beacons, runway lights, taxiway markings, sectional maps, and cockpit instruments that all contain green, red, and blue colors. The inability to recognize these colors could lead to misinterpretations of visual objects, causing endangerment to the pilot and passengers.   

Starting January 1, 2025, digital testing equipment is required for all initial medical certificates and current color-blind restrictions. If the color-blind applicant with a night flying restriction passes the digital test, the restriction will be removed and will not have to retest at future FAA medical exams.

Larry M. Diamond has a doctor of pharmacy degree and has been a pharmacist for 37 years. He is a CFII and a pilot for more than 33 years.

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