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The progressive lens is a multifocal lens that is the closest to the natural eye.
As its name indicates, the progressive lens progresses
an RX prescription from a near prescription leading to
the distance prescription including every prescription
in between. Cosmetically speaking, progressive lenses are
the most aesthetically pleasing multifocal lens by
making the progression of prescriptions virtually
seamless and showing no immediate evidence of multi
prescriptions on the lens.
The progressive lens has a visual field anatomy
of an hour glass (see image below). The two dominant
prescriptions (distance and near) have a wider field of
view. The progression in between has a narrow field of
view leaving a peripheral distortion.
There are premium progressive
lenses to help minimize peripheral distortion. Wave
front technology was introduced to spectacle lenses as a
way to minimize overall distortion. Wavefront is
commonly used as a diognosis of the eyes Freeform
progressives have also been introduced as a new
technology. By placing the ADD power and entire
prescription on the back of the lens freeform lenses
claim to eliminate front curve distortion. By
eliminating front curve distortion the freeform design
considerably increases all visual fields of view
including the intermediate, hence minimizing peripheral
distortion. |
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