HERE’S HOW WE DO IT…
This ensures that the prescription takes into account all focusing requirements, history, feedback from previous glasses, and a thorough understanding of the visual requirements of the wearer. Adam needs to have an extensive and current knowledge of all of the lens types available and we pride ourselves on this.
2. LENS SELECTION
Optimum lens selection is chosen by discussion during the visual analysis. There are subcategories of progressive lenses: some that range from computer distance to closeup, others specific for driving and the dashboard, perhaps for a music stand at 80cm and to see the conductor as well. Or a good all-rounder. Often a single-focus lens would be recommended.
3. 3D DESIGN
In recent years there’s been a revolution in progressive lens design - using 3D computer-aided design, advanced lenses are now designed with minimum distortion and have wide zones of clarity to reduce any visual discomfort. In parallel with improved design is improved manufacturing - using nanotechnology, the sophisticated designs can be made with accuracy measured in microns.
We use the most current digital measurement techniques, accurate to 0.25mm, to ensure lens positioning accuracy. Gone are the days of a pen being used on the lens and crude handheld ruler measurements. We measure reading distance, computer distance and height, dashboard distance, neck angle, all using sophisticated measuring methods. The refraction is measured using the latest Nidek instrumentation and Adam can refract accurately to 0.125 Dioptre.
If the lenses aren’t cut with the same precision as the measurements, errors will creep in. Again, we only use the latest digital methodology to ensure glazing accuracy. We always take into account contrast sensitivity and low illumination variation, such as during night driving.
COMPUTER AIDED DESIGN
We use progressive lenses made using nanotechnology which offer far more precise distance vision, wider fields of vision and an optimised reading zone compared to previous generations of lenses. The top-of-the-range bespoke lenses require additional measurements to be taken such as angle of gaze, computer distance and sat-nav position.
It's one thing having amazing computer-aided design, but unless there are machines capable of producing lenses to the same level of detail, it's for nought. Luckily, the newest generation of freeform lenses can be made with the required accuracy.
CUSTOM LENS DESIGNS
Through a combination of careful discussion and measurement of key distances such as your computer screen and other required visual requirements, Adam designs a lens specifically tailored for you. These are guaranteed to work - all you need is a little patience. They will always require a degree of adaptation.
RESEARCH AND DEVELOPMENT
A number of lens companies are investing massively in research and development into increasingly better progressive lenses. Each generation of lens offers an improvement over the last, e.g. less distortion and wider middle vision. These incremental improvements are being made through highly sophisticated computer modelling and extensive field testing. We reap the benefit of their hard work. All we have to do is order them!
THE IMPORTANCE OF CENTRATION
We measured 242 pairs of varifocals made by other opticians and found the following, bearing in mind that for success wearing progressive lenses, the centres have to be positioned accurately, within 1mm of each pupil centre.
Centres accurate to within 1mm: 14%
Generally fine and the wearer should be happy as long as the other conditions are met.
Centres out by 1mm to 2mm: 29%
Probably not thrilled with the lenses but tolerable (and therefore missing out on optimum vision).
Centres out by more than 2mm: 57%
Possibly will not tolerate the lenses and return them to the optician or stop wearing them. Either way, this will result in sub-par vision and dissatisfaction with the glasses.
This means that over half of our sample were getting sub-optimal vision due to poor implementation of their lenses - and a lot of these were high-end lenses that would have cost over £600 per pair.
Only 14% of progressive lenses in our survey were made accurately! That's shocking - except that it's not - there's way too much shoddy glasses-making going on since the advent of the optical chainstores like Specsavers and Vision Express - and this is why the public by-and-large have negative attitudes towards varifocals. That's why a Dispensing Optician trains for three years - and an Optometrist for over four - TO DO THE JOB PROPERLY!