in every way
Progressive lenses can be called progressive addition lenses (PAL), progressive power lenses (PPL) or graduated prescription lenses.
What are progressive lenses?
Multifocal lenses help people see clearly across all distances, without the need to switch glasses. An alternative to bifocals or trifocals, they correct refractive errors like presbyopia (age-related far-sightedness, common in people over the age of 40).
How do they work?
A channel (or corridor) of different lens powers runs down the front of a progressive lens. This seamless channel allows the wearer to look up to see objects at a distance, look straight ahead to see objects at middle distance, and down to read or do other close-up activities without changing glasses.
What are the benefits?
Progressive lenses are often preferred aesthetically as they don’t have the visible line that marks the two different zones of a bifocal lens (or lines, in the case of a trifocal lens).
Instead, progressive lenses provide a seamless graduation of lens strength. This avoids the jump in vision a wearer gets with bifocals and trifocals, and actually trains the eye to improve vision.