When eyeglasses need a strong prescription, ordinary lenses bulge forward from the frame, causing a “bug-eyed” look. Aspheric lenses are slimmer, thinner and lighter and eliminate that unflattering look.
Aspheric lenses can be used for essentially all prescriptions, but the difference between them and regular lenses is especially dramatic in lenses that correct high levels of farsightedness.
Aspheric vs. Traditional Lenses
Traditional eyeglass lenses have a spherical front surface, which means it has the same curve across the entire surface, much like a tennis ball.
With aspheric lenses, innovative optical design allows eyeglass lenses to be made with flatter curves, giving them a leaner, more attractive shape. They have a more intricate front surface that gradually changes in curvature from the center of the lens to outer edges.
Most aspheric lenses are also high-index lenses which are lenses that have a higher index of refraction. The refractive index determines how much light is bent, or refracted, when entering the lenses. That means high-index lenses have a greater ability to bend light rays to provide clear vision for people with strong prescription glasses.
Aspheric Minus Lenses
Lenses that correct myopia, or nearsightedness, have the opposite shape to lenses for farsightedness. These lenses are thinnest in the center and thickest at the edges. Although the slimming effect of aspheric lenses is less dramatic in minus lenses, there is still a noticeable reduction in the thickness of the edges as compared to traditional lenses for myopia correction.
When you look away from the center of a traditional lens – up, down, left or right – a slight distortion is created. Aspheric lenses reduce or eliminate these distortions, giving you a wider field of view and better peripheral vision. This is why expensive camera lenses feature aspheric curves.
- Aspheric lenses fit closer to your face
- Less lens bulging from the frames gives the wearer a slimmer, more flattering profile
- People who must have a strong prescription can choose from a wider selection of frames
Traditional round lenses with a strong prescription for farsightedness, cause unwanted magnification that makes objects appear larger and closer than they really are and give the wearer’s eyes an unnaturally magnified bug-eyed look.
The opposite is true for traditional lenses for nearsightedness. These lenses make things look smaller than they actually are and give the wearer’s eyes a small, beady-eyed look.
Aspheric lenses reduce these undesired effects significantly so that the world looks more natural to the wearer and the wearer’s eyes look more natural to others.