Conventional Progressives

Traditionally, progressive lenses have been produced using a molded blank that incorporates the progressive surface on the front side. These progressive blanks are produced in large quantities, and are available in multiple materials, each with a range of base curves, each with several add values. The wearer prescription is generated using traditional equipment to cut a simple curve, a sphere or a torus, on the back side of the lens.

The progressive design itself is fixed, molded on the front surface, and it doesn’t change for different prescriptions. All wearers of a particular progressive will end up getting identical lens designs. However, ideally a progressive lens should be different for each wearer, and the design should change not only with the prescription, but also with other factors such as the lens material, the selected frame, and the visual needs of the wearer. With conventional progressives, personalization for each wearer is not possible, and that is a significant limitation.


 

Digital Progressive Lenses

What are the advantages
of digital surfacing?

Digital surfacing technology has been a real revolution in the optical industry. This lens production technology allows the optical lab to generate and polish a complex surface on the back side that is specifically designed for each lens. With this new production method, the lens is processed from a molded blank that has a spherical front surface. The progressive design, combined with the prescription, is processed on the back surface of the lens.
The main advantage offered by this technology is the ability to produce personalized lenses. The lens design becomes unique, according to the prescription, material, frame and even the visual preferences selected by each wearer.

What makes some
digital lenses better?

The term “digital lens” applies to any lens made with digital surfacing technology. But in order to achieve optical performance superior to that of conventional progressives, the lens has to be calculated using an advanced lens design technology. The digital surface has to be computed in a way that uses the wearer’s individual information to provide better vision, on every point of the lens, for that specific person. And this is exactly what
Digital Ray-Path® does.


 

Digital Ray-Path® is a lens design technology that improves vision for the wearer through every point of the lens by implementing a realistic computerized simulation of the lens’ optical behavior when it is placed in front of the wearer’s eye. This simulation analyzes the oblique aberrations, which are optical effects that have a negative impact on the lens’ visual performance. These aberrations are evaluated at every point of the lens, taking into account the rotation of the eye and the real position of the lens.

With this information, Digital Ray-Path® is able to optimize the lens surface by compensationally correcting these undesired aberrations. As a result, Digital Ray-Path® creates a lens that provides better vision through every point of the lens. The wearer will perceive wider, more comfortable visual fields in the distance, intermediate and near vision zones.

 
  Step 1

Eye-Lens System

Digital Ray-Path® prepares a simulation of the lens in front of the eye, taking into account all of the wearer’s personalization parameters. The more parameters that are measured and provided, such as tilts or back vertex distance, the more accurate the simulation will be.

  Step 2

Space Object

Digital Ray-Path® uses information about the progressive design selected for the wearer to determine which areas of the lens are meant for distance, intermediate or near vision.

Step 3

Ray Tracing

Digital Ray-Path® simulates how the eye rotates to look in every direction, at various distances. For each position of the eye, it computes the oblique aberrations that would limit the visual quality through that particular point of the lens. Digital Ray-Path® uses this information to minimize these undesired aberrations point by point across the lens.

 

Result

A unique digital lens
optimized for each individual user