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On this page we offer an in-depth look into the advantages of digitally engineered lenses by examining some of the difficulties in correcting vision.


The Inherent Problems of Seeing Through a Lens

Most people are unaware of just how tricky the physics of light passing through our lenses can be. The truth is that correcting our vision would be a whole lot easier if lenses were paper thin, if the lens surface was always the same distance from the eye, and (this is rich) our eyes never moved! Clearly that is not the case, and so despite the wonderfully innovative lenses available, visual distortions (aberrations) will always be present on some level. Here's a look at how some factors create distortions.


Thickness of Lenses
Figure 1A: Thickness of Lens Ideally:
The front and back surfaces of the lens are parallel. This causes the refraction (angling of light) to occur uniformly.
Figure 1B: Thickness of Lens In Reality:
Thickness varies throughout lens. The amount of light refraction (convergence or divergence) changes towards the edges of the lens and may no longer match your prescription.


Distance Between Eye and Lens
Figure 2A: Distance of Light From Lens Ideally:
Lens surface is a perfect sphere perfectly matching the curve of the eye. Distance from lens to eye is the same as the eye moves around.
Figure 2B: Distance of Light From Lens In Reality:
Lens does not follow the curve of the eye. Movements of the eye cause changes in distance traveled by light causing magnification or minification.


Angle of Light From Lens
Figure 3A: Angle of Light From Lens Ideally:
Again, the lens surface is a perfect sphere matching the curvature of the eye. The angle of light from lens is the same as the eye moves around.
Figure 3B: Angle of Light From Lens In Reality:
The angle of light from the lens is a major factor in refracting light. As the angle changes, the prescription from the lens begins to change.

The Progressive Lens Problem

To further complicate matters, let's examine progressive lenses. These lenses start off with the Reading (Near) prescription already ground on the front of the lens. Once your prescription is received, an appropriate Reading lens is selected and your Distance power is ground onto the back surface. This means that the shift between Reading and Distance powers on your progressive lens is created using template models instead of being completely tailored to the way you use your eyes. There are hundreds of templates out there to match the customer's visual needs as close as possible, but the match will never be 100% perfect.


So What Is the Solution?

We always knew the inevitable shortcomings of lenses -that is, the way light gets slightly distorted here and there. But now, by using digital generators we can create lenses (like Essilor's Ipseo lens or Nikon's Seemax lens) that have microscopic corrections specifically positioned throughout the lens to account for these distortions. These microscopic corrections on the lens surface redirect the light to where it should theoretically be shining on the eye!

In the case with progressive lenses, these corrections are incorporated:

This last model is the highest quality and most advanced lens available. By studying your eye movements the lenses are ground to create a progressive lens that is 100% unique to your own vision! That is a remarkable evolution in progressive vision!


The Results?


Ask your eye-care professional about the incredible advantages digitally engineered lenses can offer you. We're always pleased to answer any questions or concerns that you may have.