The Differences Between Spherical Aberration and Aspherical Lenses?

What is Spherical Aberration?

A correctly functioning lens focuses all incoming rays of light onto a single focal point. Those of us lucky enough to enjoy 20-20 vision have eyes which focus light onto our retinas like this, meaning we don’t need glasses! But a distance vision impairment, such as near or farsightedness, usually stems from having a focal point which does not align perfectly with the retina. 

Just like our eyes, artificial lenses can also suffer from imperfections. So-called simple lenses (like we find in magnifying glasses or reading glasses) are parts of a plane or sphere: as such, they do not focus light perfectly, and the degree of imperfection is known as a spherical aberration.

Aspherical Lenses

Aspherical lenses, on the other hand, have a more complex surface curvature, which compensate for the aberration. This is especially useful for people who have strong prescription powers for nearsightedness, which can lead to a “bug-eye” look with classical lenses. Aspherical lenses are much thinner, thus reducing the magnifying effect. This also gives the wearer a slimmer profile, as the frames do not need to be as thick or chunky.

Optical Advantages

The aesthetics are not the only advantage of aspherical lenses. Their optical quality is also superior. In conventional, “simple” lenses, the further away from the centre of the lens we look, the more distorted our vision becomes. Aspherical lenses offer a wider field of clear vision, as well as improved peripheral vision. The same rule applies to camera lenses too, and top-spec models also feature an aspherical curvature.

If you are interested in trying out the advantages of these lenses, all of our glasses come with aspherical lenses, as testament to their superior quality both optically and aesthetically. For more information, speak to our expert opticians.