|
Lens Types |
ILT Lenses
- Individual Lens Technology
Bespoke lenses for
distortion free vision
The
parameters required to produce a distortion free lens have, in the past,
been so numerous that it has been impossible for lens manufacturers to
supply a lens with no distortion. With the advancements in computer
technology in the past few years, it is now possible to create a tailor
made lens, individually designed not only to your prescription, but also
specially adjusted to take into consideration the position the
spectacles sit on your face. By measuring the distance the lens sits
from the eye, and the angle it sits at (measurements which in the past
lens designers have taken a national average) we can supply a custom
made spectacle lens with practically no distortion.
Prior to ILT
technology, lens designers have traditionally relied on a set of
parameters, determined by a national average, as a basis for lens
design.
How it
works
Like a
camera, the eye has a film, called the retina. Unlike the film in a
camera, the retina is spherical, like the inside of a ball.
The eyes focusing system converges light on the retina and this creates
a clear image.
When the eye requires a corrective spectacle lens, the spectacle lens
also creates an arc of focus.
Ideally, the arc of focus created by the spectacle lens should
correspond perfectly with the retina of the eye.
The position of the arc of focus is controlled by the lens deisgners.
The distance the lens sits from the eye, and the angle, both vertically
and horizontally, determine the position of the arc. As these distances
and angles are unknown to the designers, an average figure is taken.
However, should your spectacle lens sit differently to that of the
average, this has an adverse effect on the arc of focus.
The effect this has on higher prescription, especially for varifocals
can be considerable. The distortion created by a varifocal on lower
prescriptions looks something like this.
With higher prescription however, simply by the lens not sitting infront
of the eye as the manufacturers intended, the distortion can be as much
as below.
This results in a very small field of view, not only in the reading
area, but in the distance as well.
ILT
lenses, designed around not only your prescription, but the position
they are worn within the spectacle frame, eliminating these distortions
giving far superior peripheral vision. |
