What Are High-Intensity Eyeglass Lenses?

High-intensity glasses are also called high index, or hi-index, lenses. These specialty spectacle lenses are designed to be thinner and lighter and are used for people with vision problems that normally require high-power, thicker lenses.

Significance

• Spectacle lenses work by bending light into the eye. The more near-sighted or far-sighted a person is, the stronger the required power of his lenses. Also, the stronger the lenses, the thicker they are.

Intensity and Index

• The term index means the "index of refraction" when referring to high-intensity lenses. The index of refraction is affected by the type of material that the light is passing through and the material's thickness, which causes light to bend differently into the eye.

Features

• High-intensity, or high index, lenses use a new material that bends light more efficiently than do regular plastic or glass lenses.

Benefits

• High-index lenses are thinner and lighter than traditional lenses. The glasses look better cosmetically, reducing the "coke bottle" effect, and weigh less, which makes the glasses more comfortable to wear.

Considerations

• High-index lenses tend to cause more glare problems. Anti-reflective (AR) coatings can be added to high-intensity lenses to reduce glare and make driving at night more comfortable.