Diffraction always occurs during the propagation of light waves.
Each surface of any IOL (“refractive” or “diffractive”) generates a phase shift in light waves.
Based on the level of phase shift the diffractive interference can be constructive or destructive in the image space.
![](https://liberty-lens.com/wp-content/uploads/2018/10/constructive-destructive-wave1-002-1-e1539335796594.png)
![](https://liberty-lens.com/wp-content/uploads/2018/10/WI-_1.png)
ELEVATED PHASE SHIFT * (EPS)
TECHNOLOGY
The Liberty Concept uses EPS in the central part of the optic to generate constructive interference between the 0 (far) and 1st (near) diffractive order. This revolutionary optical design generates the 3rd focal point for intermediate vision in a very unique way: