If you’ve ever had eyeglasses that feel too heavy to wear, chances are your eyeglass lenses are too thick. Here’s the 411 on different high index lenses that will slim down and lighten up your lenses.
Wearing eyeglasses is an old concept but the idea of thinner and lighter lenses that are more attractive and far more comfortable is relatively new. If you have a stronger prescription for nearsightedness, farsightedness, or astigmatism, high index lenses may be the best choice for you.
Since most people who wear eyeglasses are nearsighted, they require lenses that are thin in the center but thicker around the edges - the strong the prescription, the thicker the edges will be causing unnecessary stress on the nasal cavities. Additionally, many of today’s favorite frames are metal or plastic and have rims that are thinner than the lens itself, so bulky lenses may look awkward. This awkwardness can also be seen if you choose rimless frames since the lenses themselves are exposed.
There are many ways in which high index lenses differ from regular lenses. Eyeglasses correct refractive errors by bending or refracting light as it passes through your lens. Regular glass or plastic lenses can be quite thick and heavy if you have a high prescription because it takes more glass or plastic to refract the light. Thankfully, thinner lenses bend light more efficiently which means less material can be used to correct the same amount of refractive error. This translates into thinner and lighter lenses as opposed to the heavier conventional glass or plastic lenses.
There are quite a few advantages to wearing high index lenses as opposed to regular lenses: they’re thinner, lighter, and more aesthetically pleasing.
Due to their ability to bend light more efficiently, high index lenses for nearsightedness contain thinner edges than lenses made with classic CR39 plastic or glass in the same prescription. Given that thinner equates to lighter, using less material means the overall weight of the lens is drastically reduced. Your nose, sinuses, and ears can breathe a sigh of relief because less pressure will be placed on all three points.
Most high index lenses also have an aspheric design which makes them look slimmer and more attractive since the “bug eye” effect from magnification will be gone!
If you’re interested in purchasing high index lenses, you should know there are quite a few on the market. The wide variety is great for you, the consumer, because you have a lot of options to choose from. Granted, more options means more confusion.
There are a few things you should know before deciding on your lens. The light-bending ability of your lenses is determined by the lens material’s “index of refraction”. The index is basically the ration of the speed of light as it travels through the air and passes through your lenses.
The speed of light is reduced if it has to travel through more lens material. The bottom line: the higher the refractive index is, the thinner the lens will be. A high index lens of 1.67 will be thinner than a high index lens of 1.5.
Not every prescription can utilize high index lenses. If you’re eyeglass prescription is low, chances are you are not a good candidate for high index lenses. Additionally, if your prescription is not high enough and you opt for eye glasses with high index lenses, you could harm your eye sight - so it’s important to discuss recommendations with your optometrist before ordering.
Hillary Glaser is a social networking specialist and expert in cross-media promotion, currently working on promoting prescription eyeglasses . She is the Director of Marketing and Special Projects for GlassesUSA.com - the easiest way to buy glasses online, which now offers free shipping on all US orders with the code FreeShip10.