Progressive Addition Lenses (PAL) are multifocal lenses (glasses)
They’re used to correct focusing disorders that occur in most people after the age of 40 (presbyopia). These lenses may also be used for younger people that have disorders of accommodation, or for those individuals who have demanding near visual needs beyond the eye’s normal focusing capability. In this particular lens, distance vision is accessible through the top or “straight ahead” portion of the lens. Intermediate vision is viewable through the middle part of the lens, and reading/close vision is viewable through the bottom part of the lens. Unlike a lined bifocal or trifocal, the lens changes power in a gradient fashion from the top to the bottom of the lens – so no demarcation lines segment or obscure the lens, making this the top choice for the ability to multi-task between different visual distances and cosmetic appearance.
However, not all progressive lenses are equal! Many people have tried (and failed to adapt to) older style/conventional/basic tier lens designs that constrict the field of view to a very narrow corridor of vision, causing a very large distortion area to the immediate right and left of straight ahead gaze. These types of conventional progressives, utilize four- decades-old technology (often from the 1980’s) and are basically “semi-finished” manufactured lens blanks. They cannot be customized and are being phased out by most manufacturers due to poor wearer experience and the inability to meet modern visual demands. A wearer is expected to have narrow fields of vision, and is required to move/tilt their head significantly to find the ‘sweet spot’ in the lens. An adjustment period of up to three weeks is typical, if a person is able to adjust at all. If you or someone you know has had a bad experience with progressives in the past – chances are, this is the type of lens that gave you that bad experience (there are many retail establishments that still offer this type of product due to the low cost of manufacturing them since they are not customized at all).
In the past, there weren’t many progressive design choices available so progressive wearers had to “put up with” the limited technology that was available at the time.
However, the visual experience with progressives has changed a lot over the last few years as newer technology and newer customized lenses designs have enhanced the choices to the point where this is now the primary lens of choice for people with differing focusing needs.
Newer progressives, such as the Shamir Autograph Intelligence, now feature a specific area to see your cell phone and also have a wider field of vision for the computer to better accommodate today’s wearers. These higher quality progressives will have wider areas of vision (to the left and right of straight ahead gaze) that provide more usable vision in the lens. In contrast, lower quality progressives will have a narrower field of vision and have more peripheral distortion throughout the lens. The quality level of a progressive lens can be defined by the terms “Conventional” (see above), “Digital”, and “Free Form”.
Digital progressives have become more common due to the ease of manufacturing them. The term “digital” means that the tools used to manufacture the lens were computerized, which provide enhanced clarity to a lens – but not necessarily a wider field of vision. Digital progressives are semi-molded and then finished at a later point with the wearer’s prescription. While these lenses are clearer than conventional progressives, they are still limited by their semi-molded designs. If “digital” is the only enhancement to the lens, it may be more clear facing forward but still have significant side distortion that makes the wearer feel “sea sick”, similar to a conventional (basic) progressive lens. Many retail establishments will incorrectly market these as the “highest quality” of progressives – but digital surfacing by itself only produces a mediocre lens at best. (Free Form progressives are the highest quality lenses available.) An adjustment period of two to three weeks is typical with digitally enhanced lenses.
Free Form progressives, such as the Shamir Autograph Intelligence, are the highest quality lenses for an enhanced visual experience.
These are completely customized prescription lenses, and do not start out with pre-made lens blanks. Similar to digital progressives, they are made using computerized tools, *but* they are not limited by semi-finished/molded designs – they are completely customized from start to finish. True Free Form lenses will be branded lenses from reputable optical technology leaders, and utilize patented technology from years of research and user feedback. This patented lens technology cannot be duplicated or simulated by any generic or private label lens. Be skeptical of retail establishments that offer ‘Free Form’ with no specific brand name such as Shamir Autograph Intelligence, as these may just be standard/conventional digital progressives. Free Form progressives are made uniquely based on several parameters: your individual glasses prescription, the measurements/shape of your specific frame of choice, and custom measurements of how that particular frame sits on your face. The Shamir Autograph Intelligence progressive offers the widest and clearest area of distortion-free vision in a progressive and provides the easiest adjustment period. Most new wearers immediately adjust to their prescription within just a few days and is the #1 choice of all our patients in terms of enhanced wearer experience and visual quality.