aspherical Lens design
Ordinary Lenses are spherical in shape. The disadvantage of this is that only the central portion can be viewed without experiencing image distortion called "Spherical aberration".
Let us call that central area as "infocus" area and area outside of that is "area of aberration". When a line is viewed across the lens the line along the periphery of the lens tend to bend while those in the focus area appear straight. The higher the power of the lens the more the bending appears and the smaller the "infocus" area becomes. This is why for foirst lime lens wearer the floor may appear to cave in when looking down. This can limit your field of view and may cause nausea and headache especially for first time lens wearers.
Below is the sample of the image of grid lines when viewed through spherical lens compared to the aspheric design of Optical Dynmamics Lens.
Optical Dynamics As[pheric Lens (+3.00D)
Our Lenses use ASPHERIC DESIGN. The shape and form of the lens is calibrated and configured to expand the infocus area and minimize the area of aberration. For lens wearers this makes a big difference because aspheric lenses gives you a wider of field of vision without any distortion. Because the lens is cast from a liquid to solid form using predesigned and configured molds, there is high level of precision of lens powers and it produces the thinnest possible lens without compromising the lens quality and durability.
The rainbow colors that appear at the sides of the line is another lens aberration called "Chromatic aberration". This is prominent for high power lens especially and more visible with certain plastic lens materials used.