A high refractive index lens is a lens that bends (refracts) light more effectively than ordinary glass or plastic lenses. This is because the lens material has a higher refractive index than ordinary glass or plastic lenses. Lens materials with higher refractive index can produce thinner glass.

So, if you want a pair of thin and attractive glasses, choose lenses made of high refractive index materials on eyeglass mart. Generally speaking, the higher the refractive index of the lens, the thinner your glasses will be.

High-refractive index lenses are especially useful if you have a strong prescription for nearsightedness, hyperopia, or astigmatism. If you have a strong prescription, high refractive index lenses can make a big difference in turning thick glasses into thin glasses.

Lens refractive index range.
The refractive index of glasses lenses is about 1.50 to 1.80. The lens material at the lower end of this range will make your glasses thicker. High-end materials can produce thinner glass. The more serious the myopia and farsightedness, the more obvious the difference.

Lens materials whose refractive index is higher than that of standard CR39 plastic (1.50) and ordinary glass (1.52) are considered high-refractive index lenses. However, some high-index lenses are much thinner than others.

Here's a list of the most common lens materials used for eyeglasses. The materials are listed in order from low refractive index (thick lenses) to high refractive index (thin lenses):

CR39 (standard) plastic — 1.50

Crown (standard) glass — 1.52

Trivex — 1.53

Mid-index plastic — 1.54 to 1.56

Polycarbonate — 1.59

1.60 high-index plastic — 1.60

1.67 high index plastic — 1.67

1.74 high-index plastic — 1.74

How thin the glasses with high refractive index lenses will be depends on the following factors:

Your prescription for lenses.

The refractive index of lens.

The design of the lens.

The size and shape of the frame

You can't change your prescription for lenses-that's what it is. (unless you choose vision correction surgery like LASIK.).

But you can choose to make your glasses as thin as possible based on the other factors mentioned above. The thinnest and most charming glasses:

Select the lens material with a refractive index greater than 1.60. The higher the refractive index, the thinner the lens. The thickness of a lens with a refractive index of 1.67 or more can be less than half of that of an ordinary plastic lens. On the other hand, polycarbonate lenses (index 1.59) may be only 20% thinner than ordinary plastic lenses.

Select a high refractive index lens with an aspherical design. Aspheric lenses have flatter curves and slender contours than ordinary plastic lenses.

Select a smaller frame. The smaller the frame, the thinner your high refractive index lens will be. At the same time, make sure your pupils are as close to the center of the lens as possible. This will also reduce the thickness of the lens.