Less Magnification or Minification of the Eyes

Also, the flatter aspheric lenses end up positioned closer to the face. This is a major benefit for anyone wearing a strong correction.

For strong farsightedness, aspheric lenses reduce magnification of the eye. The eye at left is seen through an aspheric lens. Through a conventional lens, the eye at right appears larger, even though the lens is the same power.

Strong farsighted lenses have a tendency to enlarge the wearer's eyes, producing an unattractive magnified look. Strong nearsighted lenses do just the opposite: they minify the wearer's eyes so they tend to look small and beady. Positioning a strong correction closer to the eyes lessens this magnification or minification, for a more attractive, natural look.

In minus lenses for nearsighted people, the front surface curves steepen away from the center and toward the lens edge. As a result of this gradual curve change, lenses end up with thinner edges. From an appearance standpoint, the thinnest possible edges for a strong nearsighted lens are produced when the aspheric lens is made of a high-index material.

An even newer type of aspheric lens for strong nearsightedness has aspheric curves on the back side of the lens. This produces the thinnest possible edges for very strong minus prescriptions.

Source : http://www.allaboutvision.com/lenses/aspheric-lenses.htm

Buying Eyeglasses With Aspheric Lenses

Most popular lens designs can now be ordered in aspheric form, including bifocals, progressive addition lenses (no-line bifocals) and single vision. Some are made from high-index materials, too.

For several reasons, frame selection is important with aspheric lenses. In general, the best looking eyewear results when the frame is not overly large and when the eyes are centered in the middle of the frame opening. Your eye doctor or optician will guide you in selecting the best type of frame to use with your new aspheric lenses.

Taking measurements for aspheric lenses requires greater care and skill on the part of the optician, but this only requires an extra minute or two. Creating the complicated curves used in aspheric lenses makes them a little more expensive than conventional lenses. But the outstanding cosmetic and visual benefits of these marvelous lenses make them a good investment.

Since aspheric lenses are flatter and positioned slightly closer to the face than conventional lenses, some wearers may notice more reflections off the flatter back surface of the lenses. The best way to eliminate these reflections is to order an anti-reflective coating, which also improves vision through the lenses.

Source : http://www.allaboutvision.com/lenses/aspheric-lenses.htm