Peripheral vision, or side vision, is that part of vision that detects objects outside the direct line of vision (Encyclopedia, 1987).
For instance, when you read a word on a page, you are using your central vision, but it’s your side vision that tells you if the word is at the beginning or end of a sentence, or at the top or bottom of a page. Your peripheral vision also tells you where to look if someone enters the room or if a car is approaching from the side. Like most people, you are probably not aware of the limitations that would exist without peripheral vision, because you are constantly moving your eyes in order to focus with your central vision (“Peripheral Vision.” Peripheral Vision. Web. 12 Mar. 2010).
There is a small area in the center of the retina called the macula, which is less than ¼ inch in diameter, that is responsible for sharp, clear central vision and ability to perceive color densely packed photoreceptor (light-sensitive) cells in the macula control the eye’s central vision and are responsible for the ability to read, drive a car, watch television, see faces, and see detail in anything (Encyclopedia – “Peripheral Vision.” 12 Mar. 2010).
The rest of the retina handles peripheral vision that enables the eyes to see objects off to the side while looking forward. Peripheral vision is sometimes broken into rings, like a target (“Peripheral Vision.” World Book Encyclopedia. Vol. 15. Chicago: World Book, Inc, 2002. 288-89).
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In the center of the retina is the detailed macular vision where the fovea is located.
There are two versions of peripheral vision. The near-peripheral, or “paracentral” vision, is just around the center of the retina and is surrounded by the mid-peripheral vision. On the other hand, the far peripheral vision is at the edges of the field of view (“Peripheral Vision.” World Book Encyclopedia. Vol. 15. Chicago: World Book, Inc, 2002. 288-89.) There are two types of photoreceptor cells in the retina — rods and cones (“Peripheral Vision.” World Book Encyclopedia. Vol. 15. Chicago: World Book, Inc, 2002. 288-89).
The rods work best at low light levels, and the cones provide sharp vision and discrimination. The macula contains a high concentration of cones, which accounts for the sharper focus of straight-ahead vision, particularly in bright light. Peripheral vision is better in the dark because cone cells are not very useful when there is little light or color (Klarquist, 1998).
It is also very good at detecting motion.
Rod cells, concentrated at the edge, detect motion (“Peripheral Vision.” Peripheral Vision. Web. 12 Mar. 2010).
Most of the rods are located in the periphery of the retina (“Peripheral Vision.” World Book Encyclopedia. Vol. 15. Chicago: World Book, Inc, 2002. 288-89).
This is why you can often see faint objects more clearly if you don’t look directly at them. For example, a dim star is best seen when your eyes are not aimed directly at it. When you see something out of the corner of your eye, its image focuses on the periphery of your retina and you are unable to distinguish the color of what you are seeing (“Peripheral Vision.” World Book Encyclopedia. Vol. 15. Chicago: World Book, Inc, 2002. 288-89).
But because there are fewer rods, the ability to resolve the shapes of objects at the periphery of vision is limited. Normal peripheral vision, called visual field, for one eye is approximately 150 degrees from side to side. For both eyes, it is approximately 180 degrees (“Peripheral Vision.” Peripheral Vision. Web. 12 Mar. 2010).
Most eye examinations include a perimetry or visual field test to check peripheral vision (Coombs, 1992).
Vision compared to our World Today Our world today is almost the same as what George Orwell explains in his book “1984”. George Orwell came up with a story like 1984 and it is amazing that his book is almost similar to how life is in 2013. For example, in 1984: telescreens were in all public and private places, so the populace could be watched to prevent thoughtcrime. Now: Surveillance cameras are ...
The perimetry test is used to detect and monitor damage from glaucoma and other conditions that may affect the visual pathway from the eye to the brain. In medical terms, perimetry is a systematic measurement of visual field function. An instrument called a perimeter is used to plot the central or peripheral field of vision (Encyclopedia – Peripheral Vision.” Web. 12 Mar. 2010. http://www.visionrx.com/ peripheralvision.asp) Loss of peripheral vision can actually be more difficult than the loss of visual acuity. However, many low vision aids are available for people who have lost all or a portion of their peripheral vision (Hubert, 2005).
Training and optical devices, such as prisms, mirrors, reverse telescopes, and minus lenses, can improve awareness of the environment and independent travel ability.
Peripheral vision is sometimes broken into rings, like a target (Coombs, 1992).
In the center is the detailed macular vision where the fovea is. The near-peripheral, or “paracentral” vision, is just around the center and is surrounded by the mid-peripheral vision (Coombs, 1992).
The far peripheral vision is at the edges of the field of view (“Peripheral Vision.” Peripheral Vision. Web. 12 Mar. 2010).
Actual eye color comes from the iris. Variations in eye color depend on the amount of pigmentation located in the stroma. The amount of pigmentation influences how much light is reflected and absorbed. The eye color seen is actually a result of reflected light. Brown irises absorb a lot of light and are densely pigmented with melanin (Rostein, 1991).
While blue irises are lightly pigmented and have longer wavelengths that are absorbed with shorter wavelengths being reflected back cause a blue color (Hubert 2005).
Peripheral vision is used everyday whether you notice it or not. While you are driving you naturally see with your peripheral vision, the cars that on your sides. As another everyday use of peripheral vision, basketball is a great example. Guards look straight ahead while knowing where their opponents are located around them. Not everyone can see the same amount of area out of their peripheral vision. Peripheral vision is a very useful tool for knowing about your surroundings without having to turn your head.
Introduction From simple heredity experiments with garden peas, to cloning sheep, the field of genetics has come a long way. Now we are closer to mapping out the human genetic map due to advances in technology, and years and years of research. Perhaps the most influential and groundbreaking scientist, Gregor Mendel, he was responsible to provide a path to where genetics is now today with his ...