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160 Ophthalmic Lenses

near addition, generally resulting in a larger progression length for a low
addition and hence soft design. The corridor length becomes shorter and
the design harder as the addition increases. The multi design concept is
well illustrated with the change of power progression profile by addition
in the Figure 11.40.
Essilor introduced the fourth generation of progressive lenses under
the brand name of Varilux Comfort in 1993, which offered more natural
vision than any previous progressive lens designs. The near vision area in
this lens design is located high, so that the wearer can reach it easily and
naturally when lowering their gaze. Fewer head and eye movement are
required to explore the near and intermediate vision fields and hence the
wearer enjoys more comfortable posture. These advantages were because
of specific power profile in the progression zone adopted for Varilux
Comfort. For example in case of + 2.00 D addition, 85% of the full addition
is reached just 12 mm below the fitting cross compared to a minimum of
14mm or 15 mm for previous progressive designs. Due to the softness in
the lens periphery, the wearer enjoys additional comfort in the peripheral
and dynamic vision as the necessary horizontal head movement required
to explore the full of the field was greatly reduced. The asymmetry design
incorporated also offered balanced binocular vision, while at the same time
integrating the multi design concept of previous progressive lens design.
Several competitive designs from other manufacturer appeared during the
decade.
In 2002, the fifth generation progressive design – “Varilux Panamic”
was introduced. This new design was based on the success achieved by
Varilux Comfort in providing a larger field of vision, which resulted from
the softness and regularity of the lens periphery. The Varilux Comfort

Fig. 11.40: Multi-design progressive addition lens