Editing Progressive lens (section)

{{Short description|Corrective lens used in eyeglasses}}
{{more citations needed|date=January 2013}}
[[File:20100105 MultifocalGlass.jpg|thumb|right|View through a progressive lens at some distance. In normal use, a much smaller section of the lens is used, so that the distortion is much smaller.]]
'''Progressive lenses''' are [[corrective lens]]es used in [[glasses|eyeglass]]es to correct [[presbyopia]] and other disorders of [[accommodation reflex|accommodation]]. They are characterised by a gradient of increasing [[optical power|lens power]], added to the wearer's correction for the other [[refractive errors]]. The gradient starts at the wearer's distance prescription at the top of the [[lens (optics)|lens]] and reaches a maximum addition power, or the full reading addition, at the bottom of the lens. The length of the progressive power gradient on the lens surface depends on the design of the lens, with a final addition power between 0.75 and 3.50 [[dioptre]]s.  The addition value prescribed depends on the level of [[presbyopia]] of the patient. In general the older the patient, the higher the addition. They are also known as '''multifocal lenses''', '''progressive addition lenses''' ('''PAL'''), '''varifocal lenses''', '''progressive power lenses''', '''graduated prescription lenses''', or '''progressive spectacle lenses'''.