The Eyes Have It: Color Vision Deficiencies and the FAA

The human eye is a remarkable anatomic marvel however most modern mammals have dichromatic vision—that is they have red-green color blindness.   Color vision in the human eye is the result of specialized cells called cones.   The healthy human eye has 6 – 7 million cone cells and 100- 130 million rod cells to produce normal vision. The cones—blue, green, and red—are located in the center of the retina —the part of the eye that receives images from the lens and converts them to electrical impulses to send to the brain— and are responsible for color vision, light adaptation, and fine detail. The rods are located in the periphery of the retina and are responsible for night vision, brightness perception, and distinguishing shapes.

Humans, as a result, have trichromatic vision which allows them to identify over 7 million different colors!

It is estimated that approximately 1 in 12 men and 1 in 200 women in North America have some form of color vision deficiency, though most retain some ability to distinguish some colors.  True, complete color blindness is extremely rare, though the term ‘color blind’ is universally used to describe all color vision deficiencies by most non-health professionals.  Red-green deficiency is the most common color vision deficiency.

Color Vision Deficiencies 101
Protanomaly describes a deficiency where blue-green and red-purple are perceived as an indistinct grayish shade.

Deuteranomaly describes a deficiency where green and red-purple are perceived as an indistinct grayish shade.

Both protanomaly and deuteranomaly are forms of anomalous trichromatism, which means that blue, green, and red cones are present, but the pigments contained within them are abnormal.  Nearly 50% of the people with anomalous trichromatism can make precise color matches but not as precisely as those with normal color vision.
 
Red-green color vision deficiency is called dichromatism (two colors), in which one of the three cone types is absent. Dichromatism is divided into two subtypes, protanopia—where blue-green and red-purple are perceived as gray—and deuteranopia—where green and red-purple are perceived as gray.

The rarest form of color deficiency is monochromatism (one color), which is divided into rod and cone subtypes.

A person with cone monochromatism has good central vision but cannot make most color distinctions because two of the three cone types are missing.

A person with rod monochromatism, or achromatopsia (no color), has no cones at all and can therefore make no color distinctions.  A person with achromatopsia sees everything in shades of gray.

Achromatopsia affects about 1 in every 30,000 people in the US and individuals with this condition generally have very poor visual acuity and experience difficulty adjusting to bright light.

Although color vision deficiencies can be caused by eye diseases or normal aging, the majority are inherited—impacting men far more commonly than women.
 
Men therefore often pass the genetic predisposition to their daughters who are symptom-free carriers, who can then pass the gene to their sons to the extent that each male child of a female who carries the gene for a color vision deficiency has a 50-50 chance of getting the gene from his mother.

Color Vision Deficiency and the Airman FAA Medical Candidate Medical
Color vision is essential for recognizing aircraft position lights, light-gun signals, airport beacons, approach-slope indicators, and chart symbols, especially at night. The 14 CFR Part 67 regulations state that a pilot must have “the ability to perceive those colors necessary for the safe performance of airman duties” for all medical certification classes, which is why color vision assessment is a part of the flight physical for all classes.

Many new airman candidates with a color vision deficiency don’t know they have it, because it doesn’t impact them day-to-day.  Even many report having passed many other vision tests including non-commercial drivers’ license testing, because color vision assessment was not a part of the process.

Many will learn about a color vision deficiency during their first visit to an AME resulting in an automatic minimum restriction prohibiting anyone failing a color vision test from flying at night or by reference to light-gun signals.

The good news is there are certain circumstances where these color vision deficiency-related restrictions may be removed.

If you are a new pilot are found to have a color vision deficiency or if you are a current pilot with an existing color vision restriction, Steel City Direct Care may be able to help remove the restriction from your medical certificate.

Please connect with us, because we know pilots, we know the regs and we are here to help.

Whether you simply love to fly, or you fly for a living, Steel City Direct Care works to keep you healthy, well and flight-ready!

We look forward to connecting with you!

Christopher T. Conti, MD is the Founder and Owner of Steel City Direct Care, LLC, a Pittsburgh, PA-based medical practice specializing in the care of athletes and aviators.  He is an emergency medicine physician with additional training in sports and concussion health.  He is currently a Team Physician for the US Soccer Federation (USSF), U14-U17 Youth National Team player pools, Medical Advisor for the PA West Soccer Association, a local affiliate of the United States Youth Soccer Association and the Medical Advisor for the Woodland Hills School District in suburban Pittsburgh, PA. Dr. Conti serves as Medical Advisory Board Member for  SportGait and is also a Credentialed ImPACT Consultant (CIC) for sports concussion care.  Dr. Conti is a designated Senior Aviation Medical Examiner (AME) for the Federal Aviation Administration (FAA)

Disclaimer
The information, opinions and content presented do not necessarily represent the policies or opinions of USSF, the FAA, PA West Soccer, USYS, FIFA, ImPACT, SportGait, the Woodland Hills School District or Steel City Direct Care, LLC.

None of the information presented should be construed as formal medical advice, nor should it be considered an acceptable substitute for a formal virtual or in-person encounter with an appropriately trained and licensed healthcare professional.  None of the above-listed entities, including Steel City Direct Care, LCC, are responsible for any adverse outcome associated with this content.
 
If you would like to schedule a virtual or in-person visit with Dr. Conti, please contact Steel City Direct Care

Steel City Direct Care is a Direct Patient Care (DPC) practice that provides targeted & specialized in-person and virtual care for aviators and athletes of every age and level of skill and participation.