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Progressive Addition Lenses 161

design showed that the vision was a global process and the wearer would
perceive their field as larger if they had the ability to see comfortably
through the lens periphery. In the Varilux Panamic design, the balance
between the control zone and the periphery was shifted towards the
peripheral zone of the lens, so that peripheral effect were lens dramatic
than the previous designs. This change also brought the advantages of
reducing the swimming effects obtained by rotation of the head and eyes
around the field and improving binocular fusion in the lens periphery.
Clinical trials have found significant enlargement in the field of vision in
all zones of the lens.
New generation designs from other manufacturers include the BBGR
Evolis, the Nikon Presio W, the Pentex Super Atoric F, the Seiko P-ISY –
the first of the new designs to have the progression on the concave surface,
Hoya’s Hoyalux D design, is double sided progressive.
The most recent development in the progressive addition lenses is the
Varilux Ipseo from Essilor – the personalized progressive lens that takes
into account the actual degree of head and eye movement which the wearer
employs when viewing through the intermediate and near zones of the
lens. Research has been shown that each individual has specific head and
eye behavior, which can be measured and then the progressive surface is
designed to incorporate the wearers behavior.
Over the last few years rapid strides have taken place in ophthalmic
lens production technology. Through a combination of better software,
faster computer processing and free form surfacing, it has become possible
to modify some aspects a progressive design to take into account the
individual characteristic of the frame in which the lenses are to be mounted.

CURRENT PROGRESSIVE LENS DESIGN DEVELOPMENT
With the changing scenario in the trend of spectacle dispensing, lot of new
development have come in progressive addition lens designing, with special
regard to the followings:

Shorter Corridor Progressive Lens

Fig. 11.41: A typical shorter corridor progressive