Geometry of the lenses
Spherical lenses: they are lenses with a spherical curvature on its entire surface. They are easy to make. They give a very good image quality, but in high graduations there appear certain optical distortions and they are thicker than other geometries.
Aspheric lenses: they are lenses with a frontal curvature that is flattened as we move away from the center. It is usually combined with high refractive indexes to achieve more aesthetic lenses. It is especially recommended in high powers. In large powers and diameters, they give broader fields of vision due to a better image quality on the periphery. Another advantage is that they reduce the effect of minification of negative lenses or magnification of positive lenses on the image of the eyes of those wearing glasses.
Atoric lenses: every surface of a lens minimizes aberrations for a given power. When there is farsight or myopia there is only one graduation. When there is astigmatism, especially if it is high, there are two different values. Then, if you opt for a graduation, you can not do it for the other. Atoric geometry is achieved through two different aspheric powers on the same surface. The result is a lens with a much wider field of vision. Until recently, they could not be manufactured.
Free-form lenses: general use lenses, first manufactured in semi-finished. The front face is fixed by a range of powers and the rear face just gives the necessary power. Cut a spherical surface (for myopia or farsightedness) or toric (when there is astigmatism there are two spherical radii of curvature). Cutting tools are spherical.
With free-form lenses, the cutting tools are point-to-point, that is, there is no limitation when cutting a surface. We can customize the lens according to the exact graduation, the characteristics of the frame and the facial measures. There is total freedom when cutting surfaces, spherical, toric, aspherical, atoric and what we consider without limitation. You can configure the anterior and posterior surfaces so that between them they cancel the aberrations of the lenses.
In short, there are no limits in order to achieve lenses with broad, clear visual fields with high definition vision.