A
- Abbe number
- absorptance
- absorptive lens
- Active ophthalmic instrument
- addition power
- additive power trial case lens set
- Adjusting rail
- afocal lens
- aid microscope
- aid telescope
- alignment reference marking
- angular magnification
- antireflection coating
- apex
- apical angle
- arm
- as-worn power
- aspheric lens
- aspherical surface
- astigmatic difference
- astigmatic effect
- astigmatic lens power
- astigmatic power lens
- astronomical telescope
- atoric lens
- atoroidal surface
- auxiliary beam
- auxiliary lenses
aspheric lens
Lens in which at least one surface deviates from a spherical shape, i.e. the radius of curvature changes continuously from the vertex to the periphery. Aspheres from Carl Zeiss improve visual quality and also offer major cosmetic benefits. All progressive lens surfaces from Carl Zeiss feature an aspheric design. Unlike the lenses produced by other suppliers of progressive lenses, this does not mean the rise in power towards the addition which inevitably deviates from a spherical shape due to the increase in curvature. The aspheric surface design used for progressive lenses by Carl Zeiss enhances the quality of the wearer’s vision. An additional benefit is flatter, cosmetically more attractive lenses.