Spherical lenses are a type of glass lens used in optics to correct for refractive errors such as nearsightedness (myopia) or farsightedness (hyperopia). These lenses are curved, like the surface of a sphere, and work by refracting light rays to a different focal point onto the retina. They are opposite in nature to cylindrical or toric lenses, which are used to correct for astigmatism. Spherical lenses are used both in glasses and contact lens designs.