High Index Lenses

If You Have Thick Glasses, Can You Make Them Thinner?

If your prescription results in thick eyeglasses lenses, you’re well aware of the negatives and the stigma they can cause.

Can I Make My Thick Glasses Thinner?

For starters, they’re very heavy. All-day use can lead to constant slippage and leave indentations on your nose. The lenses may not fit properly within the frame, sticking out behind it and adding to their obvious thickness. Perhaps worst of all, you feel like you’re wearing a magnifying glass in from your eyes; the distortive effects of your strong prescription makes your eyes appear either too small or two large for your face.

Luckily, high index lenses are available to eliminate most of these concerns. Available in a number of different indexes, high index material can result in lenses that are lighter, thinner, and less distortive than conventional glass or plastic lenses. But they’re not perfect, and they’re not for everyone. To help you decide if they’re right for you, let’s look at the advantages and disadvantages.

High Index Material Advantages:

• Higher index results in less use of material
• Lighter than standard plastic or glass
• Thinner than standard plastic or glass
• Reduced edge size
• Allows for multiple single- and progressive-use designs

“Index” is a measurement of how much light is refracted, or bent, through the material of a lens. It’s this refraction that focuses light in the right places and corrects your vision condition. The higher the index rating, the less material required to make a lens in a particular prescription…hence the lightness and thinness of high index lenses.

If you suffer from a very strong prescription, the curvature required of your lenses is relatively severe. If formed from standard glass or plastic, a substantial thickness of the material is necessary to accommodate that curvature. But because of their refractive properties, high index lenses allow the same prescription to be cut using much material. The result is lenses that are thinner, lighter, and with smaller edges.

High Index Material Disadvantages

• Higher cost
• Abbe value
• More brittle and reflective

For some, the difference high index lenses make in their eye-wear is almost miraculous. But this “miracle” comes at a price. The expense of high index material – due to the cost of the manufacturing process and the material waste that is associated with the more exacting process of forming, grinding, and finishing high index prescriptions – can lead to eye-wear that costs significantly more than standard-lens eyeglasses.

Additionally, Abbe value – a measurement of the lens distortion you see when you look through your lenses – is also increased in high index lenses. So although thinner, lighter high index lenses offer cosmetic benefits, they do not surpass traditional lenses (especially those made of glass) in vision quality. And high index lenses can be more brittle and much more reflective than standard materials. Because of this, an anti-glare coating is strongly recommended with the purchase of any high index lenses.

Consider all these factors when trying to determine if high index lenses will benefit you. You don’t have to live with thick lenses anymore…but be prepared to experience the above-mentioned drawbacks if you make the switch to high index lenses.