Tag Archives: retina

“What Color is This?”

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Throughout my life I have been corrected numerous times when stating the color of an object or material. Shades of purple and blue can get mixed up as well as shades of green and red. I am often corrected by my fiancé when picking out new clothing at a store, and there are even times when I have to ask her, “What color is this?” Although it can be frustrating at times admitting that I am wrong and my fiancé is right, this form of colorblindness has not affected me too much in my daily life. Maybe this colorblindness is a reason as to why I often chose neon colors as my favorite because they are the easiest for me to identify?

Unfortunately for my younger sister, this problem has become much more of an obstacle. During this class we have learned that red/green colorblindness can be hereditary and this has proved to be true for her as well. She is in her sophomore year at The United States Air Force Academy and recently found out she is red/green colorblind just like I am. However, she suffered immediate consequences regarding her future in the military. This colorblindness meant that she will never be allowed to pilot an airplane like she had once hoped. Many of the indicator lights in an airplane are small dots of red and green next to each other, so the slightest hesitation in determining them could prove deadly. Although I know this seemed like a huge setback for her at first, I believe she is handling it quite well. As a result of not being able to fly a plane, she has learned to fly her body, and has become an avid skydiver over the last year. She even is planning on helping me earn my skydiving license this summer.

This red/green colorblindness is a result of genetics. When light enters the eye is hits the rods and cones in the retina. The cones are responsible for color vision and contain photo pigments that respond to the amount of light that is hitting them. There are three types of cones in the eye that allow a person to see color when they send signals to the brain together. However, if any of the cones are deficient, then a person will not be able to see a full spectrum of color. My sister and I have most likely both inherited this from our parents due to a bad X chromosome. The difference is that I inherited this from only my mother because as a male I only have one X chromosome. My sister however, has received deficient X chromosomes from both my mother and father because she has two X chromosomes and still is red/green colorblind.

There are many tests to determine if a person is colorblind and the most popular is a dot test. These tests are often available for free online and can help a person gain some insight into their ability to see color. The following website has a free colorblind test for those readers who are interested.

http://enchroma.com/test/instructions/

Walt Disney World’s IllumiNations at Epcot

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For Spring Break I travelled with a few of my friends to the happiest place on earth where the days were beautiful and sunny and the nights were clear and mild. On Wednesday night we travelled to Epcot and stayed late enough to see the IllumiNations: Reflections of Earth fireworks show. For those of you who have not had the pleasure of visiting Epcot, the park is a circle comprised of different countries and in the center is a huge lake. This is where IllumiNations is held and throngs of people crowd around the “world” to watch the magic begin over the water. The sun was finally setting and the last rays of light danced across the water. I’ve seen a number of sunsets before but this was the first time I was able to break down what was really happening with the light, the way it traveled through my eye and how I was still able to see the light show in the dark.

Let’s begin with the sunset and how the light from the sun traveled into my eye. Here’s a picture of what it looked like:

sunset

We learned in class that when the sunlight is traveling through the atmosphere some rays are absorbed by particles while others are scattered in different directions. Next, the light that has made it through the atmosphere will either be absorbed or reflected when it hits the surface of an object. I had time before the sun went down to snap a picture of Rafiki and Simba to show you what I mean. The colors that you see have been reflected while the colors you don’t see have been absorbed. For example, let’s take a closer look at Rafiki’s light blue cheeks. We see light blue because that color blue on the electromagnetic spectrum has been reflected into our eye while the other wavelengths like red, yellow, green, etc. have been absorbed.

lionkingflowers       rafiki cheek

The light that is reflected from Rafiki’s light blue cheeks first makes contact with the cornea of our eye. The cornea is a clear surface at the front of the eye so most of the light is transmitted through it into the eye. The cornea is the primary refractive surface of the eye and has 80% of the focusing power, which means the cornea is able to bend the light in such a way that the picture becomes a clear image on the retina. Once the light reaches the retina it will strike photoreceptors, which will basically absorb the light, which leads neurons in the retina to fire action potentials all the way up to the brain. The retina transduces, or serves as a translator that receives the light and sends the “message” up to the brain in a language that the brain can read and understand. Thus we are able to clearly focus and recognize the world around us!

The light of day was quickly disappearing and the light show was about to begin. The entire park went dark except for an illuminated globe that was floating across the water. We learned in class that we are able to see glow-in-the-dark objects because they become our new light source. You can see what I mean from the picture below.

illumi

IllumiNations was a great show and the fireworks were fantastic! I have a new found appreciation for the world around me now that I know the process that goes into letting me see.

fireworks

Works Cited

“Sensation & Perception: Home.” Sensation & Perception: Home. N.p., n.d. Web. 17 Mar. 2014. <http://sites.sinauer.com/wolfe3e/home/startF.htm>.