The opportunities for single-vision aspheric lenses are relatively well known. Aspheric lenses improve the cosmetics of a pair of glasses by using surface curves that are flatter centrally and progressively flattened (in plus  prescriptions) as one moves from lens center to edge. The result is lenses that are thinner overall than the same prescription in standard spherical lenses with steeper curves. This thinning and flattening reduces the magnification of the wearer’s eyes as seen through the lens by others, as well as the world the wearer sees, and when specifically controlled ensures peripheral vision is optimized to be equal to or better than the peripheral vision in standard “best form” spherical design lenses.

For the wearer, this results in lenses that look better and perform better since the world they see is closer to natural size. In addition, the lenses provide a larger clear field-of-vision through the window of the lens frame, since magnification of objects seen through the lens has been neutralized. However, modern aspheric semi-finished lens blanks are rotationally symmetrical—that is, within a base curve, there is only one amount of asphericity and it is the same in all meridians for all prescriptions for which the lens blank is intended. Therefore, prescriptions with cylinder corrections (for astigmatism) have only
one meridian corrected by the asphericity.

For patients with astigmatism, the resulting areas of clear vision are improved most significantly in the sphere power meridian of the prescription. The cylinder meridian would not have the correct asphericity due to the difference in power and the field of clear vision in that meridian would be reduced when compared to the other meridian. If the ability to aspherize the power in the cylinder meridian was also possible, then the field of clear vision in both meridians would be further improved and you would be able to offer the same
quality of vision to the full range of single-vision wearers, including those with high prescriptions. This is, in fact, the case for lenses called double aspheric.

These lenses have two different amounts of asphericity on the same surface, located 90 degrees apart. Only a few manufacturers cast finished lenses with
an atoric back surface (different asphericity in each meridian) and these have been typically limited to 1.67 high-index lenses. Another option is to free-form
the back surface of the lens with the correct asphericity for each power, but this approach is as yet very limited in availability.

A unique and patented solution is to use the Double Aspheric lens from Augen Optics. It is available to your laboratory as a front surface, double aspheric, semi-finished lens blank in Trivex and 1.56 high-index. Your laboratory only needs to grind the back surface to create the prescription in the same way it now supplies any Rx back to you.