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Eyeglasses | Optical Centre Smartbuyglasses UK

Thick Glasses: What You Need to Know

Thick Glasses - The Basics

Thick glasses are a pretty common way of improving your eyesight. However, with technologies like high index lenses getting more popular every day, is it time to ditch your thick lenses?

The answer is a pretty resounding yes. It used to be the case that the stronger your prescription, the thicker your eyeglasses’ lenses would be. However, as eyewear manufacturing methods have improved, it’s so much easier to find some incredibly advanced lenses - i.e. both thin and strong prescription. They’re by far the best choice if you want thinner, lighter lenses and eyeglasses that are as attractive and comfortable as possible.

Before we investigate the advantages of high index lenses, let’s discuss thick glasses and why you should consider trying something new.


Why Are Thick Glasses Lenses So Thick?

The stronger your prescription, the thicker your glasses generally are. The way in which eyeglasses correct sight is by using curved lenses. Those who are short-sighted will have lenses that are thicker at the edge and thinner in the middle. It’s the opposite for long-sighted wearers: their lenses are thick in the middle and thin at the edge.

Now for the science: refractive errors in your sight are measured in diopters, but what relevance does that have to lens thickness? As that measurement increases, your lenses require more curvature to correct your sight - i.e. more lens material; the higher your diopter rating is, the thicker your lenses become. Some prescriptions are so high that lenses appear absurdly large and heavy and can distort how you look.


High Index Lenses - The Solution?

The best solution to clunky thick glasses is getting yourself some sleek high index lenses. If you have a long-sighted prescription (which can make conventional lenses very heavy), lightweight lenses can provide an even bigger jump in quality. Most high index lenses also have an aspheric design. This gives them a slimmer, more attractive profile and reduces that magnified ‘bug-eye’ look which is prevalent in traditional long-sighted prescription lenses. This is part of their main two advantages which we’ll examine below.

  • They’re thinner. Because of their ability to bend light more efficiently, high index lenses for short-sightedness have thinner edges than traditional lenses with the same prescription power.

  • They’re lighter. Thinner edges require less lens material, which reduces the overall weight of the lenses. Lenses made of high index plastic are lighter than the same lenses made of conventional plastic, so they're more comfortable to wear.

While high index glass lenses also have thin edges, high index glass is heavier than conventional glass, so there is not quite the same level of weight saving with glass as there is with plastic lenses.


Thick Lens Glasses vs High Index Glasses - Refractive Index

While there is a wide variety of thin, lightweight high index lenses out there, some of them are more efficient at bending light than others.

The light-bending ability of eyeglass lenses is determined by the ‘refractive index’ of the lens material. This index is a number: the ratio of the speed of light when it travels through air to the speed of light when it travels through the lens material.

The more the light is refracted inside the lens, the slower it travels. Therefore, lenses that bend light more efficiently have a higher refractive index than those that bend light less efficiently. 

Additionally, lenses with a higher refractive index are thinner than lenses of the same strength made out of less refractive materials.

Simply put: the higher the refractive index, the thinner the lens.


AR Coatings for High-Index Lenses

All lens materials block some light from passing through the lens. This light reflects back off the lens surface, which can cause distractions or reduce your quality of vision in dark environments. While conventional glass or plastic lenses reflect about 8% of light that otherwise would reach the eye, high-index lenses reflect up to 50% more light than conventional glass or plastic lenses.

For the best quality of vision and aesthetic appeal, it's worth exploring high-index lenses with anti-reflective (AR) coatings already applied. AR-coated high-index lenses allow almost all light to pass through, improving your vision AND how other people see you (AR coating virtually eliminates lens reflections so others see your eyes, not your lenses). Studies have shown that eyeglass lenses with anti-reflective coatings can give you a real advantage when driving at night, as they allow more light to enter your eyes.


Arise HD Prescription Lenses

If you’re looking for some high-quality lenses that don’t compromise on style or substance, the Arise HD Clarity Collection offers the best options for ordering prescription lenses online. When it comes to buying prescription glasses online, SmartBuyGlasses has you covered - with a wide selection of frames at competitive prices, now paired with premium lenses.

The Arise Clarity Lens Collection comes packed with protective elements to provide you with an unbeatable pair of prescription glasses. From scratch resistant and anti-reflective coatings to UV 400 and superhydrophobic protection - these lenses are guaranteed to keep your eyes comfortable in any situation.

If you’ve found this article interesting, read more about diopters and lens indices here. Alternatively, click here to read more about prescription glasses at SmartBuyGlasses.

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