Accommodation is the adjustment mechanism of the eye to keep an object in focus on the retina as its distance from the eye varies.
Presbyopia is an age-related condition that causes blurred near vision. As people age, the lens inside the eye becomes harder and less elastic thus begins the loss of reserve accommodation. It typically starts at around age 40 and affects everyone, even those who've never had vision problems before.
When presbyopia begins, people will squint or hold reading materials at arm's length to help their eyes focus. Eye strain, headache, and fatigue are common symptoms of presbyopia.
For centuries presbyopia has been corrected with the use of bifocal lenses.
Progressive Addition Lenses (PAL) commonly referred to as no-line bifocals are actually no-line trifocals whereas they had three fields of vision; distance, intermediate and near.
A progressive corridor uses on average approximately 10mm of the lens vertical surface, located in the prime usable area of the lens. A patient with sufficient reserve accommodation does not require an intermediate zone they only require distance and near vision correction.
The Duolux® bifocal is the ideal solution for emerging presbyopes and conventional bifocal lens wearers because it is a true bifocal (there are only two visual fields distance and near with no intermediate zone).
Wearing the Duolux® will prepare the patient for a possible change to a progressive in the future, when they have lost the majority of their reserve accommodation, making progressive adaption easier