Major Structures Of The Eye

Explain the visual process, including the stimulus input, the structure of the eye, and the transduction of light energy.

After being shown a picture of an elephant they eye will take the light that is reflected from the object and it will enter the eye through the pupil. Then the light will be focused by the cornea and the lens to form a sharp image of the elephant in the retina. The retina is the network of neurons that cover the back of the eye and contains the visual receptors for a person vision. The visual receptors are made up of cones and rods that contain light sensitive chemicals called visual pigments. Visual pigments reacht to light and cause a triggered electrical signals to occur. These electrical signals will then flow through a network of neurons and this network of neurons is what makes up a persons retina. After the flow through the network of neurons occurs the electrical signals will emerge from the back of the eye in the area

Focusing an image clearly onto the retina is the initial step in the process of vision, but although a sharp image on the retina is essential for clear vision, a person does not see the picture on the retina. Vision occurs not in the retina, but in the brain. Before the brain can create vision, the light on the retina must activate the visual receptors in the retina by a two-element

Eye Vision Inc, a long-standing medical device manufacturer, has signed a contract to sell Holland Hospital the Clear View Laser and a two-year separately priced maintenance plan for $1 million and $0.2 million respectively. On a when-and-if available bais, Eye Vision Inc. will provide software updats that is embedded with the Laser to maintainance purchasor. The software has never been sold without Laser for its functional necessity. In this memo, as explained below, we conclude that:

 A.accommodation B.the concentration of cones in the fovea C.chemical structure of the vitreous humor D.the prevalence of amacrine cells in the

When it comes to vision, we see things based on the light reflected from surfaces. The reflected light waves enter the eye through the cornea at the front of the eye, it's resized at the pupil, focused by the lens, and hits the retina at the back. The light is then detected by rods and cones, photoreceptors, which alters the light into electrical signals. The optic nerve transmits those vision signals to the lateral geniculate nucleus, where visual information is transmitted to the visual cortex of the brain then converts into the objects that we see.

The retina is what houses the eye’s rods and cones. The eye has about 6 million cones and 120 million rods. Both rods and cones get their names from their shape. Rods do not provide color vision, and are sensitive to dim light. Cones function well in the day and provide color vision.

The primary focusing lens is the cornea, the clear window at the very front of your eye. The internal lens, called the crystalline lens, is adjustable and alters your focus from distance to near. Sometimes, one of these two lenses may have a radius of curvature that is too steep. In myopia, it is often the cornea that is too highly curved. It is this curvature which is altered in laser eye surgery. Shortening the eyeball has been tried, but it has not been without the potential of serious and permanent damage. Often in situations where the crystalline lens is forced into an excessive plus power curvature, myopia can result. This may occur from near vision stress, a

The eyeball holds many parts to allow eyesight. The retina holds the key to allowing the human eye to see color. The pupil appears as the black part of the eye that people see, the pupil however does not have much to do with comprehending color. As Clarence Rainwater said in his book “The pupil is simply the hole in the iris through which light enters the eye.” (84) The light then has to pass through many parts of the eye before reaching the retina such as the transparent cornea, the aqueous humor, the lens, and the vitreous humor. Clarence Rainwater described the retina as “... the eye’s sensitive inner surface.” (86) The exciting part of the eye starts here. The retina holds the key as stated by Clarence Rainwater, “... a complex system

In the center of the iris is the pupil. Iris function is to control the size of the pupil. This pupil dilation allows a certain amount of light to enter the eye. A bright environment stimulates limiting diaphragm to contract the sphincter muscle and reducing the amount of light entering the eye. A dark room stimulates the dilator to relax and dilate in the effort to increase the amount of light entering the eye. The pupil constriction also occurs when the lens changes focus so that the eye can see something on a fence. This is known as the, Äúnear reflection., AU Sometimes the student does not respond properly due to problems in nerve or cranial

Fluid circulating inside the front portion of the eye is produced by a structure called the ciliary body, which is located behind the iris. This fluid moves through the opening of the pupil, passes into the space between the iris and the cornea, and drains out of the eye through a tissue called the angle. With glaucoma, the passing of fluid

Pax6 is a transcription gene it functions as a regulatory gene transcription, and plays a key role in the development of the eye during embryonic development. Because Pax6 is a transcription factor gene to ensure that there is proper development, it has the ability activate or deactivate gene expression. That being said Pax6 acts a master control gene as stated before for the development of the eye and other sensory organs. There are more functions for the Pax6 gene, but I will be focusing more on the evolution of it as well as more on the formation of the eye, in a variety of species. Pax6 is an interesting gene because it is the same gene, or relatively the exact same gene in many species. One could take Pax6 from a human or mouse, which both have the same amino acids sequence and introduce it to a Drosophila melanogaster. The fruit fly will produce a perfectly functioning fruit fly eye even though the regulatory gene in fruit flies is called eyeless. This is because they are orthologous to each other. The development can vary in all species on how the eye develops “Eyes of very diverse type and structure ranging from simple light-sensitive receptors to complex image-forming eyes can be found in the animal kingdom” (Tomarev). It can be seen that genes like Pax6 or eyeless are all related in that they create photosensitive cells.

The eyelids are made up of four layers, the skin, muscle, connective tissue and conjunctiva. The process of vision occurs when light waves from an object, enter through the iris. Light then passes through the lens of the eye, a double convex structure that is used to focus the light, and then reaches the retina. Inside the retina are rods and cones. Rods are used to sense light and dark, and cones are used for sensing colors. Whether the light entering the eye hits the cones or rods, a signal is sent across the optic nerve to the brain where it is processed and viewed as an image. Some issues people have with eyesight are as follows. Those who are farsighted are unable to see things clearly at a short distance, compared to a long distance. This occurs when the light that enters the eye is focused behind the retina, and not directly onto it. When the cornea is not curved enough, this happens. Nearsightedness is when one can see objects clear at a short distance, but not at a longer distance, and this is often caused by a change in the cornea. A Blind spot is the location the optic disk, where the optic nerve fiber exits, and at this location there are no cones or rods, so there is a blind spot.

I looked into the physics of the eye itself and into corrective lenses because I wear glasses. The human eye is a very complex piece of anatomy. Like a camera, the eye is able to refract light and produce an image that can enable someone to see.