The five senses include sight, sound, taste, hearing and touch. Sight, like the other senses is closely related to other parts of our anatomy. The eye is connected to the brain and dependent upon the brain to interpret what we see. How we see depends upon the transfer of light. Light passes through the front of the eye cornea to the lens. The cornea and the lens help to focus the light rays onto the back of the eye retina.
The cells in the retina absorb and convert the light to electrochemical impulses which are transferred along the optic nerve and then to the brain. The eye works much the same as a camera. The shutter of a camera can close or open depending upon the amount of light needed to expose the film in the back of the camera. The eye, like the camera shutter, operates in the same way. The iris and the pupil control how much light to let into the back of the eye. When it is very dark, our pupils are very large, letting in more light.
The lens of a camera is able to focus on objects far away and up close with the help of mirrors and other mechanical devices. The lens of the eye helps us to focus but sometimes needs some additional help in order to focus clearly. Glasses, contact lenses, and artificial lenses all help us to see more clearly. Over time, the vitreous becomes more liquid and can detach from the back part of the eye, which can create floaters.
If you notice new floaters or flashing lights, it is important to see your eye doctor, because a detached vitreous can cause a hole a condition called a macular hole to develop in the retina. The retina is the light-sensitive tissue that lines the inside surface of the eye, much like wallpaper. Cells in the retina convert incoming light into electrical impulses. These electrical impulses are carried by the optic nerve which resembles your television cable to the brain, which finally interprets them as visual images.
The macula is the small sensitive area in the center of the retina that provides clear central vision. The fovea is located in the center of the macula and provides the sharpest detail vision.
The retina is the light-sensitive tissue that lines the inside surface of the eye. The retina contains photoreceptor cells that convert or process incoming light into electrical impulses. There are two types of photoreceptors: rods and cones, which are the light-processing cells responsible for peripheral side and central straight-ahead vision.
You can get a closer look at different parts of eye with this interactive eye diagram from the National Eye Institute. You can learn more about the parts of the eye and refractive errors, including myopia nearsightedness , hyperopia farsightedness , and astigmatism both near and far blurriness at Refractive Error and Astigmatism and A Guide to Eye Conditions.
Jake Whalen: Living and Coping with Keratoconus Jake Whalen is a freelance copywriter who has struggled for most of his life with keratoconus. Learn more about the basics of effective eye care, including: The difference between normal eye and vision changes and symptoms of vision problems The different types of eye care professionals Questions to ask when you see an eye care specialist.
Check out our Getting Started Kit for more ideas to help you live well with low vision. Sign up with VisionAware to receive free weekly email alerts for more helpful information and tips for everyday living with vision loss. Some Facts about the Retina The retina is the light-sensitive tissue that lines the inside surface of the eye.
Rods The specialized, highly light-sensitive retinal processing cells that are able to function in low light levels. They are less sensitive to color perception. Composed of retinal nerve fibers that exit the eyeball through the optic disc, traverse the orbit, pass through the optic foramen into the cranial cavity, where they meet fibers from the other optic nerve at the optic chiasm.
Variable-sized black circular opening in the center of the iris that regulates the amount of light that enters the eye. Forms a thin membranous lining of the rear two-thirds of the globe; consists of layers that include rods and cones; bipolar, amacrine, ganglion, horizontal and Muller cells; and all interconnection nerve fibers. Transparent, colorless gelatinous mass that fills the rear two-thirds of the eyeball, between the lens and the retina.
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