You should never take your eyes for granted; don't wait until you have a problem to have a vision exam. You should have your eyes checked annually.
The eye is very delicate and in order to see well, all parts must be able to function properly. Always try to protect your eyes. Did you know that the bones in your head protect your eyes from injury; even the eyelids close out unwanted light and also dirt. Your tears from nearby tear ducts work hard to keep the eye's surface moist and clean.
The eye is filled with a clear jelly in its center called the vitreous humor. Three layers of tissue surround the vitreous humor. There is an outer layer, which has tough tissues and protects the eye; then ...view middle of the document...
The focus is the point at which all of the light rays intersect. After light passes through the lens, it falls on the retina, the part of the eye that absorbs light rays and changes them into the electrical messages that then create images.
There are receptors in the retina called photoreceptors. These are of two types: rods and cones. Rods are cells that are very sensitive to light but can only distinguish black from white, and cones detect color but are not very sensitive to light. At the center back of the retina is a small yellow spot called the fovea, which contains no rods; it allows the eye to view things in great detail. There is also a blindspot at the point at which the optic nerve joins the eye, and it contains neither rods nor cones. The cord of nerve fibers that carries messages to the brain is the optic nerve. The process by which the brain puts these different images together is called stereoscopic vision. Peripheral vision is the process of seeing objects at the sides of your eyes.
Healthy vision requires three basic processes: formation of an image on the retina (refraction), stimulation of rods and cones, and conduction of nerve impulses to the brain. Malfunction of any of these processes can disrupt this chain of processes, producing a visual disorder.
Here are some tips to protect your eyes. When you work in an area in which the eyes need protection, be sure to wear protective safety glasses to keep the eyes from harm. This will protect your eyes from chemicals, light, and heat. If you are participating in sports, you will also need the proper helmets or goggles to prevent injury. When working near moving particles where there is a great deal of blowing sand or dust or even smoke, don't forget to wear goggles. These are common for many industrial workers, but some work around the home also makes their use necessary.
Many rays injure the eyes. The cutting flame of the acetylene torch produces rays highly injurious to the conjunctive. Bright light from glowing blocks of metals and arc lamps also affects the conjunctive and may produce blurred vision. Infra-red rays from glowing glass have long been known to produce "glass blower's cataracts." Infra-red rays are also responsible for a condition known as snow blindness, which is not caused by snow but from the rays reflected from the snow. Permanent or serious damage to the eye can result from any of these rays, and the use of protective devices, goggles, or sunglasses is necessary.
There can be many wounds made by penetration of the eye that cause loss of sight or even permanent damage. Children playing with sharp-pointed toys, scissors, darts, etc., can be very dangerous. The use of wooden sticks is dangerous, too, because these can become broken and then form sharp, jagged ends. Prevention is important, so it is wise to discard toys that can damage and be very careful about buying new toys that may cause harm, especially to small children.
When you do very close reading,...