Can the Sun Change Color Perception More Than a Mild Color Vision Deficiency?

Brett wants to become a pilot. But he is suffering from a mild form of color vision deficiency which disqualified him.

He is now looking for any possibility which could show, that in some cases weak colorblind people are not less suitable than people with normal color vision as there are many factors which can have quite an impact on your performance and which you always have to be aware of.

Read his request, you might be able to help him:

I have been diagnosed with mild deuteranomaly and have been disqualified from USAF pilot training. I am currently working to get an exception to policy that would allow me to still go to pilot training, and I know how difficult this will be. But I need help with research for my exception to policy package. Today I came up with a simple but interesting idea and tried researching but was unable to find the information I need.

The idea is that since I have mild deuteranomaly, my M (green) cones are shifted a few nanometers towards the L (red) cones. I also know that many other factors can affect the color perception of people with normal color vision, such as the position of the sun in the sky, weather, hazy, cloudy, etc… So what I’m looking for is a measure of how much the position of the sun would affect the color of an object. I’d bet the bank on the sun shifting light wavelength more than my condition.

I’ve looked into color temperature a bit and found at dusk or dawn sunlight has a color temp of approx. 3200 K and at noon its around 6500 K. My problem is I’ve been unable to relate this change of 3200 K to 6500 K to a change in wavelength (nanometers).

Any information on how much the sun would affect color perception, or how many nanometers a person with mild deuteranomaly would be shifted would be greatly appreciated.

I can be contacted at:

After reading his thoughts you maybe realized that your situation is quite similar. Hereafter you can read his whole story which might help us all to find a better solution to the problem, that many colorblind people are rejected from a job just because of some color vision tests, which are most of the time to unspecific and much to restrictive.

So I’ll start my story about 3 years ago when I began applying to become an Air Force Pilot through OTS. I was in my senior year at Virginia Tech working on my degree in Aerospace Engineering. After turning in my application to OTS I had to wait a while for the boards to make their decision, so I asked to have my flight physical done so that I would know if I was medically qualified before I even entered the Air Force. With the exception of distant visual acuity everything went well and I was given a waiver for my vision (20/200 uncorrected). I passed the PIP1 color vision test with 13/14 each eye. Unfortunately I ended up not being accepted to OTS and was quite disappointed.

Searching for what’s next, I found the possibility of a 2-year AFROTC program I could do while working on my Masters degree. I looked at school and was accepted to Embry-Riddle Aeronautical University’s Aerospace Engineering Master’s program and the AFROTC program their. During my first year their I was selected for a Pilot slot before even going to field training.

I went on to complete my work at Embry-Riddle and commission 3-MAY-09. I had to sit around all summer waiting to EAD but finally did on 3-SEP-09 and began to long drive to Laughlin AFB to wait for ASBC at the end of October, IFS, and someday UPT. I’ve been at Laughlin for just over a month now and received orders to go to Brooks AFB last Wednesday for MFS (Medical Flight Screening). At MFS they did a a few tests, but the only thing I was a bit worried about was my distant vision waiver. All of my tests went fine except for color vision. I scored 10/14 for the PIP1 for each eye failed a few other tests. They kept me for additional color vision tests and determined that I have hereditary red-green (deuteranomalous) green-weak, color deficiency. This is completely disqualifying for Pilot, Navigator, ABM (not sure about this one), Combat Control, Combat Rescue, Special Tactics Officer, OSI, Test Pilot School as an Engineer, and 99% of Astronaut positions.

This has been quite devastating since all of those jobs I listed have been my dreams and backup plans in case my dreams didn’t work out. Having them all stripped away in one day has motivated me to fight this to the end. I’ve been researching quite a bit to come up with anything I can do. I don’t really know who to contact but I’m planning to start with my commander. I plan to tell my whole story and explain why I believe I am fit for at least one of those jobs.

I’ve gone my entire life (24 years) without knowing I had any form of color deficiency and have accomplished a lot; I just don’t see how it can be so bad that I would be at a disadvantage now. I’ve read about potential advantages that red-green colorblind people have such as better night vision (which I found one paper going against this), being able to see “faster” (I haven’t found any scientific evidence), and most notably being able to see through and detect camouflaged objects more easily (still don’t have a solid source, just mentioned in other sources).

From what I can tell the only way I might be able to get around this is to get my commander or someone above him to write an “exception to policy” that would basically say that they are willing to take a risk on me since I might be able to make up for a deficiency with other aptitudes. Other than that, political figures may be able to use their pull somewhat to get me around this (but I know none personally).

If anyone has any information that may be useful to my cause please contact me at Otherwise I’ll be busy looking for other careers (which don’t require perfect color vision) that will be as exciting, dangerous, noble, and challenging (both mentally and physically) as that of an Air Force Pilot.