Color Commentary

Now that the summer months are upon us and we are in vacation mode, I thought I would take a break from proselytizing about optometry. I was thinking about a question my son asked me, which every optometrist likely hears at some point: “Why is the sky blue?” This question reminds me of how complex color perception really is. Much of our understanding of color focuses on physics. Yet in practice, as optometrists, what often matters more is how people perceive color in everyday life. As I sit here watching the World Cup, it makes me think about color vision deficiencies and sports.

Statistically, 1 in 12 men and 1 in 200 women have a color vision deficiency. Most of the time, when a patient has a color vision deficiency, I chart it, and if it is a child, I educate the family about potential vocational limitations that may arise, such as certain military aviation careers. Generally, however, I do not make a big deal about it.

During the World Cup, I realized that maybe I should be more considerate of the effects color vision deficiency can have in the sporting arena. The ‘kits’ (a.k.a. uniforms) of the team are such an important part of a team’s culture and a billion-dollar moneymaker for professional sports. Historically, the home team wore a colored (typically dark) jersey and the away team wore a white jersey. This created a contrast between teams regardless of one’s ability to perceive the colors. However, over the years, this convention has frequently been violated, resulting in opposing teams wearing jerseys that may appear indistinguishable to a viewer with red-green color vision deficiency. 

People with red-green color vision deficiency may have difficulty distinguishing reds from greens and may also confuse shades of brown, orange, and yellow, depending on the type and severity of the deficiency. There is a classic example from a 2015 NFL “Color Rush” game in which the Buffalo Bills wore all-red uniforms while the New York Jets wore all-green uniforms. This was very difficult for many viewers with color blindness and brought public awareness to some of the challenges that people with color deficiencies may experience. 

Athletes with a color vision deficiency have an ‘invisible’ handicap. The percentage of male elite athletes with color deficiencies is thought to be closer to 5% in contrast to 8% in the general population. In addition to deciphering jerseys of the opposing team, they may have difficulty seeing a red or orange ball or cone on a green field. Fields used for multiple sports may also contain a variety of colored lines that are difficult to distinguish. Additionally, tracking colored balls across colored backgrounds, such as a blue sky, may be more challenging. 

Not to say this cannot be overcome. Optometrists can help athletes explore contrast-enhancing, filtered lenses or tinted lenses that may improve performance in certain situations and allow them to reach their fullest potential. 

Now back to the initial question, “Why is the sky blue?”  It really has little to do with color perception. Blue is among the shortest wavelengths in visible spectrum and is scattered more strongly by molecules in the atmosphere, a phenomenon known as Rayleigh scattering. Because shorter wavelengths are scattered in all directions, the sky appears blue to our eyes. 

Erin Draper, O.D.
POA President