Thinner Lenses
Why bother and When?
The vast majority of lenses glazed in spectacles these days are made of standard plastic of refractive index 1.5.
Most prescriptions will find this material is satisfactory in terms of thickness and comfort, but what about stronger prescriptions and anyone troubled with the weight of their glasses on their sinuses?
Thankfully we also have a whole range of thinner and lighter lenses to choose from. Here is a quick summary of the 4 main lens options to choose from and why you might pick each lens.
1.5 index is readily available as a stock lens at an economical price and looks great in most basic prescriptions. If cost is an issue or the prescription is small this is likely to be the lens of choice.
After 1.5 we have a mid index lens at 1.6 index, which is up to about 20% thinner and lighter than standard plastic 1.5. A prescription above +2.50 or -2.50 would start to see good improvements with a 1.6 index lens. Lower prescriptions may see a little benefit but need to weigh it up with the extra costs involved.
Of course anyone trying to keep the weight of their lenses to an absolute minimal or just wanting the thinnest lens for their prescription possible can consider thinner and lighter options every time. My point would be 20% reduction on a +0.50 may not justify any extra cost involved.
Following on from the 1.6 mid index, the next lens option is the 1.67 Hi-Index plastic lens, which is up to about 33% thinner and lighter than standard plastic 1.5 depending on prescription used. A prescription above +3.50 or -3.50 again would really start to see improvements but perhaps even more so a stronger prescription would benefit from this lens material. If you are a -6.00 lens wearer you will be all to well aware of the weight of your spectacles and this is where hi index “thinner & lighter” lenses can make a world of difference.
The thinnest lens in plastic is the 1.74 index which is up to about 40% thinner and lighter than standard plastic 1.5 depending on the prescription used.. This is an excellent thin & light material for thoses stronger prescriptions giving optimum comfort and aesthetics if cost is not an issue.
Hope this helps make sense of the lens numbers!
Most prescriptions are basic but if you do have a stronger prescription reducing your lens weight and enhancing your lens appearance at the same time it’s your optical win win!
For any further lens information please visit our lens information page or if you have any other questions please just ask: