Adeline's Colored Contact Lenses Insight

Vision

How Our Eyes Work

Next time you're caught trying to cut in front of someone in a line, you can truthfully say you didn't see them. That's because our eyes don't "see" objects at all--they only see the light those objects reflect.

When light enters the eye, it is absorbed and converted into electrical impulses by retinal nerves. These impulses are in turn sent to the brain where they are interpreted as visual images.

Vision begins when light enters through the cornea, (the transparent outer covering of the eye) and is focused with the help of a "crystalline lens" behind the pupil at a point directly on the retina. The retina is a thin layer of tissue at the back of the eye that contains millions of tiny light-sensing nerve cells called rods and cones.

In bright light conditions, cones provide clear, sharp central vision and detect colors and fine details. Rods provide peripheral or side vision and also allow the eyes to detect motion and see in dim light and at night. However, only about four in ten people have normal visual acuity. For the rest, clear vision may be attained by refocusing light rays with the use of corrective lenses.

How Do Contact Lenses Work?
Contact lenses are designed to rest on the cornea, the clear outer surface of the eye. They are held in place mainly by adhering to the tear film that covers the front of the eye and, to a lesser extent, by pressure from the eyelids.

As the eyelid blinks, it glides over the surface of the contact lens and causes it to move slightly. This movement allows the tears to provide necessary lubrication to the cornea and helps flush away debris between the cornea and the contact lens.

Contact lenses are optical medical devices, primarily used to correct nearsightedness, farsightedness, astigmatism and presbyopia. In these conditions, light is not focused properly on the retina, the layer of nerve endings in the back of the eye that converts light to electrochemical impulses. When light is not focused properly on the retina, the result is blurred or imperfect vision.

When in place on the cornea, the contact lens functions as the initial optical element of the eye. The optics of the contact lens combine with the optics of the eye to properly focus light on the retina. The result is clear vision.