Dual Digital Vision - A New Way to Look at Digital Surfacing

By Bob Colucci
The term “digital surfacing” describes a process for transferring an optical surface onto a lens. The main difference between digital surfacing and traditional surfacing is the ability of digital surfacing to produce complex surfaces with extreme accuracy— whereas traditional surfacing can only produce spherical and toric surfaces Traditional Surfacing is accomplished using hard tools called “laps.” Because laps are rigid, they are only capable of producing surfaces which are spheres or toric (cylindrical). This is the primary limitation of traditional surfacing.

Digital Surfacing uses a pointed cutter that travels across the lens like a record needle. A computer program controls the position of the point, instructing it to cut deeper in some places and shallower in others along a predetermined path. The resulting surface is relatively smooth. By eliminating the need for a rigid tool, digital surfacing is capable of producing complex aspheric or even progressive surfaces.

Design Drives Lens Performance

Digital surfacing is a process for making optical lenses—it is not a design. Digital technologies open new possibilities, but just being “digital” is not enough to guarantee high visual performance. Using a digital surfacing process to create a progressive lens does not have any bearing on the quality of the progressive design. The ability of a lens to provide visual comfort and performance is determined by the quality of the design—not the process used to produce the lens.

Digital surfacing is not a standardized process shared by all manufacturers. There are numerous variables in both equipment and production processes that may affect the quality of the finished lens:

•The most significant variable involves the process used to calculate the design. Essilor uses a completely unique calculation for each prescription

•Some manufacturers use standard equipment while others like Essilor invest in R&D to modify equipment, improve quality and consistency

•Digital surfacing requires significantly more calibration and process control compared to traditional surfacing. Some manufacturers only generate data files necessary to produce the lens while others like Essilor make sure that the equipment is producing what has been designed.

Two Sides are Better Than One

In looking at lens design, Essilor realized that performance can be optimized by using complex curves on both the front and back surfaces of the lens. Providing better vision through dual side design requires a comprehensive approach, including lens design, high technology manufacturing equipment used to create each lens, and the manufacturing protocols that ensure quality at every step of the process. With the advent of digital surfacing, Essilor stepped back and took a “from the ground up” look at the entire process of lens creation. From this global reassessment, Essilor created Dual Digital Vision (DDV) a new approach to both lens design and lens manufacturing.

Just like Blu ray HD technology has set a new standard in home media entertainment, Essilor DDV sets a new standard in digital surfacing technology. To enjoy a high quality viewing experience with HD DVD, it requires High Definition content, Blu Ray DVD player and a HD TV.

Likewise, to provide a better visual solution to consumers with digital surfacing, it requires a superior design, controlled processes to translate consistently this design, and high precision manufacturing equipment to transfer the design on to the lens. Only Essilor DDV lenses integrate dual surface design, controlled processes, and patented precision equipment to provide visual benefits beyond the capability of any other lenses.

Essilor DDV Lens Availability

The Varilux 360° series and Definity lenses are all Essilor DDV lenses.

Dual Digital Vision sets Essilor digital surfacing lenses apart from the competition by considering the lens design and the lens production from every angle. By taking this comprehensive approach, DDV allows Essilor to take full advantage of the benefits digital surfacing can offer.

Bob Colucci is the head of Essilor’s Independent Distribution Division (IDD).

CURRENT ISSUE


September/October 2014