As someone who has spent over 35 years working with spectacle lenses; lens designs, materials, tints & coatings, I often forget that most people think of them just as a couple of pieces of plastic. Worse than that: people think that they’re all much of a muchness.
Most modern spectacle lenses are hi-tech precision-made, even custom-made items. Twenty years ago it was common to get spectacles made in ‘about an hour’. Now the customisation and huge variation in lens designs means delivery times can be a week or more. That’s progress…
Lens designs vary from the most basic single vision (single focus) to various types of progressive (multi-focals, varifocals) or degressive designs (‘computer’, ‘anti-fatigue’ & ‘indoor’ lenses).
All the above lens types can be made in various different materials to maximise properties such as thickness, weight, scratch resistance & chip resistance.
Lenses can be ‘hard-coated’, tinted, polarised or photosensitive (e.g. Transitions®). Multi-layer anti-reflection coatings allow up to 10% more light to pass through the lens and minimise front surface reflections, ‘ghost’ images etc. These coatings can be blue light blocking (good for intensive computer use) and can prevent back surface UV reflections (good for all outdoor spectacle wear).
Spectacle lens manufacturers, varying from small operations to multi-nationals, are dotted all over the globe. Quality varies hugely, not just in lens materials, but in lens designs (affecting image quality), prescription accuracy and the quality and durability of lens surface coatings.
To ensure you have the most appropriate spectacles for your visual and lifestyle needs, seek expert advice from the Optometrist or Qualified Optical Dispensers at North Lakes Optometry.