Differences Of Purpose - Progressive Lenses
There have been some amazing advances in progressive lens technology. As of this writing, four progressive lenses are leading in technological advances. There are differences in what they try to accomplish, and how they approach that.
Keep in mind that
what is best for one person is not best for another. Some designs may perform better for certain activities, and what is great for general use may not perform well for specialized use.
To give an example, think of these vehicles:
- Panel Van
- Ford Pickup
- Dump Truck
Each of these vehicles is designed for a different purpose. A Lambo would hardly do the job of hauling sheetrock around, and a dump truck would impress a first date in the wrong way.
Why 'Best' Is Relative
So too with progressive lenses. You may want the best, but best is relative to the task at hand. And there is no sense going luxury when you don't need it. Get the lenses that will help you perform at a level you need. Frequently, that means getting multiple pairs rather than trying to get one 'ultimate' lens.
The most advanced progressive lenses are digitally ground, freeform, are customized for the wearer and compensated for the position of wear.
- Digitally Ground - A computer controlled lathe removes material and polishes the back side of the lens. The distance power and add power are ground on the back side of the lens.
- Freeform - There is no single design. several factors can go into determining the shape of the back surface of the lens for the best optics. The computer determines this on the fly on a case by case basis.
- Customized - because of computer control, the design can have longer or shorter intermediate zones (called corridors) between the distance and near zones of the lens, as needed by the patient. The relative widths of the distance, intermediate, and reading zones can also be customized. Some designs consider the power of the opposing eye at any given point to enhance binocular vision.
- Compensated - The is also aspherically ground into the lens to improve the focus at the edges of the lens. This enables flatter, thinner lenses which still deliver excellent clarity.
Sometimes these lenses are referred to as 'high definition'. The proper way to make these lenses is to include measurements such as vertex distance, pantoscopic angle, and frame wrap in addition to the monocular pd and monocular height measurements that are given with less advanced progressive designs. If you are paying for HD progressive lenses, make sure your eye care provider is taking all the measurements.
The Four Technologically Leading Progressive Lenses Are:
Varilux is by far the most recognizable progressive lens brand. The X Series lens supercedes the S Series lens which is now discontinued.
The X series is the only lens to feature Xtend Technology which they say reduces the need for head movement when looking to focus, especially within the intermediate zone.
Essilor's W.A.V.E. Technology, brough over from the S Series lens, increases sharpness and decreases distortion
Synchroneyes - Considers the opposite eye, improves binocular vision, and decreases off-balance sensation
4D Technology - Compensation for position of wear improves optics.
The Camber lens differs from other digital progressive lenses in that it uses an aspheric front surface lens blank. By moving some of the add power of the lens back to the front of the lens (as in older style progressive lenses) it improves the optics and reduces the compensations needed on the back surface of the lens. Both the front and back surfaces of Camber IOT progressive lenses are aspheric. The back surface of the Camber IOT lens is freeform.
The Camber IOT comes in three forms. Distance optimized, near optimized, and intermediate optimized. The corridor length is customizable, and the lenses are compensated for position of wear when that information is provided.
Patients benefit from a wider reading area, better optics, and easier adaptation.
Offers a several fully customizable progressive lenses. They claim 20% wider fields of view through personalization. They feature the following technology:
Eyepoint Technology III - Design differences between minus and plus lenses so that myope and hyperope wearers experience the same optimized viewing zone.
Natural Posture - moves the reading zone based upon the lens power to compensate for magnification or minification prismatic effects. This reduces the need for head tilt in higher prescriptions.
Intellicorridor - a faster progression gives more add quicker. An improvement for comfort when digital devices are pervasive.
As Worn Quadro - Compensation based upon position of wear.
Sport / Performance Lenses
Workplace / Occupational Lenses
A tool from Shamir to help you Select Your Lenses
The Unity VIA progressive lens series was introduced by Vision Service Plan. The VIA series of lenses has 5 designs:
VIA Eiite - most advanced and customized
VIA Plus - somewhat customized
VIA Wrap - a sport oriented lens
VIA Mobile - a digital device oriented lens
VIA - least customized of the series
Unity claims that their VIA progressive lenses were designed through user feedback, and an iterative process of design improvements, producing a lens that has beaten the competing lenses in double blind tests at all add powers and all distances.
VIA progressive lenses feature these technologies
Variable Inset - differences in patient pupillary distance will affect the needed inset for the near zone. This technology ensures that the eye travels through optimal optic zones for the wearer.
Automatic Reading Height Optimization - The Unity Via computer algorithm does computations on the frame size and wearing height to make sure there is enough reading area and enough intermediate for the wearer to get the best vision throughout the range of distances. This customization is automatic and based upon the position of wear parameters.
Digital Viewpoint Technology - A compensation that extends clear viewing out to the periphery of the lens. It is based upon the lens power and position of wear.
Advanced Fit Technology - A Variable Corridor available only in the Unity VIA Elite lens. It is a non linear intermediate corridor. The intermediate corridor is S shaped to better center over the eyes at intermediate distances.
Premium Progressive Lenses Have Their Place
While all the lenses we covered offer exceptional performance, they are not for everyone. Certainly the advanced technology comes at a price premium.
For many, Other lens designs will perform better for the task at hand. You certainly don't want to throw the best lenses available up against an activity that is guaranteed to ruin them - such as surf fishing. For many purposes, a less advanced, and less expensive lens is sufficient.
But for those that demand the best, these are state-of-art technology for progressive lenses.