Human Perception of Light

Human Perception of Light

Sources

http://www.richmondeye.com/eyehealth_contacts.asp

http://kilby.sac.on.ca/departments/science/snc2d/CourseDocs/sb_pdf/is10_unit_d12-1.pdf

http://www.boybdream.com/articles.php?articleid=91385

http://en.wikipedia.org/wiki/Optics_and_vision#Contact_lenses

Contact Lenses

An alternative to glasses are contact lenses. Contact lenses are an excellent alternative for correction of refractive errors, and the technology of lenses continues to improve.

Contact lenses perform the same function as eyeglasses but they have more advantages when it comes to areas such as work, sports, or where glasses are inconvenient. Contacts are worn right on the cornea of the eye which provides vision that is more natural, objects appear in correct position and size without any distortion. Contact lenses do not get affected by rapid body movements in sports or similar activities and they remain in place where eyeglasses are unstable during the same activities. As far as comfort and convenience, they do not pinch your nose, press against your ears, or slide down when you perspire.

Optics

Perception of light is an ability that not everyone shares equally. Many people at some point in their life benefit from procedures or technologies that improve perception of light. The most important technological device related to human perception of light is the lens. It can be a tiny plastic contact lens that floats on your cornea, a lens made of hardened plastic or tempered glass used in eyeglasses, or actually reshaping your cornea through laser

eye surgery.

Laser Surgery

Eyeglasses

Glasses are frames bearing lenses worn in front of

the eyes for vision correction and protection from

UV rays. Modern glasses are supported by temple arms

placed over the ears and pads on the bridge of the nose.

Many people have trouble focusing clearly at some

point in their life. As you age, many people become less able to see clearly as a result of the lenses in their eyes gradually hardening. Far-sighted people see distant objects clearly, so if you wear glasses with a converging lens in front of the eye, it brings objects into focus. Near-sighted people see nearby objects clearly, and in this case a diverging lens is placed in front the eye to bring objects into focus. Polarized sunglasses block harmful UV rays and reduce glare. Anti-glare night vision glasses help drivers at night when trying to see past

the headlights of oncoming cars. In cases like these,

eyeglasses with yellow or blue tint are

helpful.

Laser eye surgery, also called refractive eye surgery, is a procedure that involves reshaping the cornea using energy from a laser in order to allow the eye to focus correctly. It can be used to correct near-sightedness, far-sightedness and astigmatism. Laser surgery eliminates the need for corrective lenses (contacts or glasses). Since laser surgery is only several decades old, some people delay having this procedure because

long-term effects are still unknown.