The eye is the organ of vision. It has a complex structure consisting of a transparent lens that focuses light on the retina. The retina is covered with two basic types of light-sensitive cells-rods and cones. The cone cells are sensitive to color and are located in the part of the retina called the fovea, where the light is focused by the lens. The rod cells are not sensitive to color, but have greater sensitivity to light than the cone cells. These cells are located around the fovea and are responsible for peripheral vision and night vision. The eye is connected to the brain through the optic nerve. The point of this connection is called the "blind spot" because it is insensitive to light. Experiments have shown that the back of the brain maps the visual input from the eyes.
The human eye is not sensitive to the polarization of light, i.e., light that oscillates on a specific plane.
Because the eye is such an important and complex part of our body, we have many features which protect the eye. The eyebrows are the strips of hair above your eyes which prevent sweat from running into them. Eyelashes help keep the eye clean by collecting small dirt and dust particles floating through the air. The eyelashes also protect the eye from the sun's and other light's glare. The eyelids sweep dirt from the surface of the eye. The eyelid also protects the eye from injury. Tears are sterile drops of clean water which constantly bathe the front of the eye,keeping it clean and moist.
Not all people have perfect vision. People who can see things up close, but not far away are considered to be nearsighted. This happens when the light entering the eye focuses on a point in front of the retina. On the other hand, people who can see far away objects but not those that are up close are farsighted. Farsightedness occurs when the light that enters the eye focuses on a point behind the retina. Whether a person is nearsighted or farsighted, glasses or contacts help that person to see things much more clearly.
RECOMMENDATION
It’s so important to take care of your eyes, but you may not think about it very often. No matter how much makeup you put on them or how much you workout, if your eyes look tired or lack luster it will show. Be alert for symptoms of vision problems or visual stress , like tired or burning eyes , blurred vision , difficulty with distance vision , difficulty reading , or doing close work and trouble reading . Wear proper safety eye wear when doing things like using power tools, playing sports like basketball, karate or kick boxing. Provide adequate lighting when reading and watching TV. Take rest breaks from visually demanding tasks and from the computer screen. Wear proper sunglasses for protection from the sun. Necessarily schedule a comprehensive eye health and vision exam every 12 to 18 months to help ensure your correct eyesight.
Your eyes require specific vitamins and minerals optimum health and function. Current medical studies suggest that patients with several diseases of the eyes may benefit from daily dietary supplements of antioxidant vitamins that include zinc, selenium , vitamin A , vitamin C and vitamin E.
You May Also Find These Documents Helpful
-
• rods and color vision- scoptic-refers to dim light levels at or below the level of bright moonlight; rods are sensitive to scoptic light levels; but all rods have same sensitivity to wavelengths of light, making it impossible for them to discriminate colors…
- 2092 Words
- 9 Pages
Better Essays -
Nearby objects are clear but far objects are blurry and the eyeball has grown too long or the cornea is too steep in Myopia. And Hyperopia is and eye imperfection that is usually caused by the lens not being round enough or the eyeball is too short, with this close objects are blurred.…
- 278 Words
- 2 Pages
Satisfactory Essays -
Our retina is partially composed of many small nerves (which function as receptors of light); these receptors are arranged in rows on the inside of…
- 478 Words
- 2 Pages
Satisfactory Essays -
Occipital Lobe – this is the part of the brain that controls eyesight and our ability to see…
- 2398 Words
- 9 Pages
Better Essays -
1. The cornea controls and focuses light in the eye. The cornea is responsible for about 75 percent of the eye's focusing power. As light enter the eye, the cornea refracts it onto the retina to help the eye focus on objects.…
- 506 Words
- 3 Pages
Satisfactory Essays -
Phase Contrast Microscope: contrasting lit intensities are provided by the optical system, even if the object is unstained…
- 901 Words
- 4 Pages
Good Essays -
Depth perception is the ability to determine the distance of objects and spatial relations of objects at various distance. The retina is made up of several layers within contain rods and cones. Cones are any of the cone shaped receptors in the retina that respond to color. Rods are the long shaped receptors that respond to faint light. The eye perceives optic illusions because of blind spots in the eye that are due to where the optic nerve enters the eye and is lacking rods and cones. This area is insensitive to light; the brain will often assume what is there and fills it in with what makes sense.…
- 3746 Words
- 15 Pages
Better Essays -
In Jorge Luis Borges’ piece from Ficciones, “Blindness” and Annie Dillard’s piece from Pilgrim at Tinker Creek, “Seeing”, we read writers’ perspectices on their own blindness. The writers contradict the common fallacies our culture has about blindness with their own personal experiences. Although both writers portray blindness in a positive light, each writer uses his disability to enhance his lives differently. Borges depicts his loss of sight as an opportunity to learn new things about life and himself, while Dillard uses her blindness as a way to better appreciate nature.…
- 589 Words
- 3 Pages
Good Essays -
“I always come this far and open my eyes. The spell breaks and I try to re-see the rabbits, so tame through having never been hunted, that played in the hedges and along the road.” (Pg 35) In the novel Invisible Man, by Ralph Ellison, the motif eyes reoccur constantly, the first time being in this quote. Throughout the novel eyes come to resemble many different things such as the ability and inability to judge, the taking in of surroundings, and many other things.…
- 1245 Words
- 5 Pages
Good Essays -
Besides the cones, which detect light entering the eye, the biological basis of the opponent theory involves two other types of…
- 895 Words
- 3 Pages
Good Essays -
There are three distinct layers in the eye with the outer layer consisting of the cornea and sclera, the middle layer containing the iris, ciliary body and choroid and lastly the inner layer which has the retina (Galloway et al. 2006). The cornea’s main functions is to protect the eye against infection and to refract and transmit the light to the lens and retina. The iris controls the size of the pupil, thus limiting the amount of light that reaches the retina. The ciliary body controls the shape of the lens and the choroid provides nutrients and oxygen to the eye. The retina contains neurons that capture and processes light. Light enters the eye via the outer components and travels through the neurons of the retina and is accordingly captured by the photoreceptors present at the back of the retina. The neurons then translate the visual information received from the eye into nerve impulses that travel from the optic nerve to the lateral geniculate nucleus to be interpreted (Willoughby et al. 2010). Each eye sees a marginally different image which is combined in the brain to become one…
- 1776 Words
- 8 Pages
Better Essays -
Occipital Lobe – this is the part of the brain that controls eyesight and our ability to see…
- 3316 Words
- 10 Pages
Powerful Essays -
cells do not discriminate among colors of light. They help us see in dim light. Cone cells…
- 657 Words
- 3 Pages
Good Essays -
The human eye works like a camera. The cornea acts like the window of the eye; when light enters through the cornea, the light rays bend in a way that they pass freely through the pupil. The cornea is also where most of the focusing in the eye occurs. The…
- 1568 Words
- 7 Pages
Good Essays -
The outer consists of a white layer called the sclera. The front of the eye, in the area protected by the eyelids, the sclera is covered by the conjunctiva, which runs to the edge of the cornea the clear, curved layer in front of the iris and pupil. Light enters the eye through the cornea, the cornea serves as a protective covering for the front of the eye and also helps focus light on the retina at the back of the eye. After passing through the cornea, light travels through the pupil. The iris controls the amount of light that enters the eye. The pupil dilates and constricts as the amount of light in the immediate surroundings changes. The iris allows light into the eye when the environment is dark and allows less light into the eye when the environment is bright. The size of the pupil is controlled by the action of the pupillary sphincter muscle and dilator muscle. Behind the iris sits the lens. By changing its shape, the lens focuses light onto the retina. Through the action of ciliary muscles, the lens becomes thicker in order to focus on nearby objects and thinner to focus on distant objects. The most sensitive part of the retina is a small area called the macula, which has millions of tightly packed photoreceptors and each photoreceptor is linked to a nerve fibre that all bundled together to form the optic nerve. The optic disk, the first part of the optic nerve, is at the back of the eye. The…
- 1774 Words
- 8 Pages
Powerful Essays