In our office we use predominantly Nikon lenses. We also have access to Essilor, Hoya, Rodenstock, Sola, and Zeiss lenses.
Quite often you will hear us talk about technology advances with progressive lenses. We like to explain this to you because there is a huge difference in progressive lenses 20 years ago and progressive lenses today. Although we still have access to some of those older lenses, we will usually put you into a newer design. We want you to have the best vision possible. Ok, so now to explain some of this to you…
Short-corridor vs. Long-corridor
With older style designs, you would get the widest and tallest reading and intermediate area with a long corridor lens, where the minimum segment height requirement was right around 21mm. So if you were a receptionist, we would have suggested a deeper frame to accommodate these.
Short-corridor lenses were more used for aesthetics and less for usability and comfort. They had a more narrow and shallow reading area and almost no intermediate zone compared to long-corridor progressives, but became popular because people wanted smaller frames; and we could accommodate a minimum segment height around 18mm.
Although nowadays they still have short and long corridor lenses, we can give you a comfortable sized reading and intermediate area with a height of 14mm or 15mm.
Hard Design vs. Soft Design
even though most newer styles of progressives are soft designs, we do still have access to hard design lenses. Basically, this is just a way to explain how the progression is in the lens.
With hard design lenses, the 3 zones are very distinct. Some people didn’t like this design because there was no nice flow to the lens.
Soft design lenses still have 3 prescription zones, but the prescription changes gradually to ease the wearer into the next zone. This is usually the favoured by wearers, which is probably why most of the new progressives coming out have a soft design.
Conventional vs. Digital
Older styled progressive lenses had the prescription ground into the backside of a lens using an instrument called a “chuck”. If you make a fist with your hand, that is kind of the shape of it, except it has a material comparable to sandpaper on the end.
This chuck gyrates to sand away the lens. It is a multi-set process, going from using coarse grit sandpaper, gradually working to a fine grit, and then finally the buffing process. This method has been used for almost a century, with the main downfall being that you can never fully polish out or fill scratches, no matter how fine. It is also a pretty timely process, so most companies would use semi-finished lenses, where the prescription was already ground into the front of the lens.
Most of the newer technology lenses are considered digital. They are made using a computer that guides either a diamond drill, a laser, or a combination of the two, to slice away the plastic to generate the prescription. With this precise method, the lens laboratory can create a lens for you within 1/100th of a diopter of your prescription!
Your sight will also be a lot clearer, crisper, and sharper than ground lenses because there are no scratches whatsoever.
We really hope this helps you have a better understanding of what we offer and why we offer the lenses we do. Our main objective is that you see the absolute best possible!