Spherical intraocular lenses have a uniform curvature across the surface of the intraocular lens much like the surface of a ball. Aspheric intraocular lenses have a more complex but more non-uniform shape which is better in terms of the quality of vision that a patient can achieve. Aspheric intraocular lenses are a more advanced form of intraocular lenses. Spheric intraocular lenses were developed earlier before the development of aspheric lenses.
The purpose of asphericity or making an aspheric intraocular lens is to reduce the optical spherical aberration which is a type of optical distortion that affects the quality of the image that a patient sees, especially at the edges of their visual field. Minimizing spherical aberration can also potentially lead to a vision which is sharper, more detailed, particularly in low light conditions or in individuals who have larger pupils. Because aspheric intraocular lenses are more advanced and newer forms of lenses, there is of course a price difference between spherical and aspheric lenses. The advantages to using an aspheric intraocular lens are better contrast sensitivity, reduced layer and halos, better potential for night vision, and an overall improved quality of vision.
Aspheric intraocular lenses come in mono focal lenses as well as multifocal aspheric intraocular lenses. The final choice of placing an aspheric or spherical intraocular lens depends on the needs of a patient and their preferences. The surgeon’s expertise is also extremely important, and a surgeon’s experience and preferences in the use of a particular kind of lens also plays a role in determining the most suitable type of intraocular lens that he or she chooses for their patient.