There Are Two Basic Types of Lenses Available Today for Glasses and Intraocular Lenses
How Does the Eye See Our World?
The human eye works in a very similar manner to how a camera works.
In a camera, the lens focuses light or objects onto the film or now a computer chip.
In the eye, the light is first focused by the cornea (clear portion of the eye in front of the iris and pupil) through the pupil. The lens behind the pupil finishes the focusing of light onto the retina (the portion of the inside lining of the back of the eye that works just like the film of a camera receiving the image and sending it onto the vision center of the brain). If the size and shape of the eye are good then we see clearly. If the size and shape are not normal, then we may be nearsighted, farsighted, or have astigmatism which blurs the vision.
Types of Intraocular and Eyeglass Lenses
A regular conventional lens has the same curvature or shape over the entire surface of the lens.
Light that is focused from the edge of the lens will be refracted or bent stronger than the light that enters in the center of the lens. This leads to aberrations and decreased quality of vision. One way that you can see this is to look out of the peripheral portion of your glasses and you will notice that your vision is not as good. The stronger the strength of the lens the more evident the blurred vision will become.
Aspheric lenses flatten towards the edge of the lens. This allows for more light rays to be focused together. This results in sharper vision with less aberrations or distortion.
Aspheric lenses are used in high end cameras and binoculars. Aspheric lenses are used in telescopes and the Hubble Telescope.
Many lenses used for eyeglass prescriptions are now using this technology to improve the quality of vision with eyeglasses.
Numerous intraocular lenses used during cataract surgery are using this technology. These lenses can provide sharper vision with less distortion and aberrations.