When it comes to progressive lenses, the offer is as vast as the price range. Regularly, the communication departments of major lens manufacturers announce the release of new progressive lenses with innovative technologies. "HD, Panoramic, 360, Comfort+, etc...". For the client (and the vision health professional), it can be difficult to distinguish between marketing and real technological progress.
What is a progressive lens?
Progressive lenses are lenses that correct presbyopia, this natural aging of the eye becoming problematic around the age of 40 and making near vision more difficult. These lenses also correct all other visual deficiencies of the wearer (myopia, hypermetropia and astigmatism). Thus, the wearer can see in a single bezel at all distances (Near, Intermediate and Far).
Blurred areas ("Optical Aberration") at the periphery
Laws of physics oblige, areas of aberrations (blur) are induced on the periphery of the lens resulting in a reduced field of vision compared to a single vision lens:
Above: sketch of the lateral aberration zones of a progressive lens
Consequently, the transition to progressive lenses requires an adaptation period depending on the individual, the usage and the prescription.
- Far vision: look ahead, always in line. It is the head that must turn, not the gaze.
- Intermediate vision: you have to look in the middle of the glass, with your head straight.
- Near vision: always keep your head straight, but this time look down at the bottom of the glass.
- Areas of aberrations: avoid looking to the sides because vision in these areas is distorted.
- Stairs: With the steps appearing much closer, look two or three steps further.
New generation progressive lenses: "Free-form" or "HD" progressive lenses
Over the past ten years, traditional lens machining has been largely replaced by point-by-point digital machining. The prescription is slightly modified to take into account the different parameters and the glass is shaped with expensive machines of very high precision. Today, almost all progressive lenses on the market use these technologies. This has made it possible to slightly widen the visual field, but the intermediate vision zone (for computer use for example) remains limited and the aberration zones are still present. If you work long hours in front of a computer, these glasses probably won't be your best friends.
In addition, the HD designation can be confusing. It is an image, by its number of pixels per square cm which determines the definition, not a lens through which we look at this image.
Simple vision and degressives to your rescue
If you work several hours a day on a computer or read a lot, it is quite possible that here at Bonhomme à lunettes, we will strongly advise you to invest in specialized lenses. Single vision lenses will give you perfect vision over the entire surface of the lens. At a given distance, it's the most comfortable solution and it also happens to be the most affordable! Added advantage: it does not require any adaptation.
If you work at several distances (double screen, reading + computer for example), we could recommend decreasing lenses offering a small variation in power between the top and the bottom of the lens. The field of vision is wider than with progressive lenses.
In conclusion
When you are offered the best glasses and the bill is close to 4 figures, what to do?
We work outside of “classic marketing for optical boutique”. We therefore offer you what, in our opinion, is the best value for the money with a guarantee of adaptation to your glasses. Because no matter the asking price, progressive lenses may not be the product for you. It depends on your lifestyle, your visual needs or the ergonomics of your workstation. That's why it's important to discuss these issues with your eye care professional.