Lens Materials

Plastic (CR39)

Much lighter lens material than glass and is very cost-effective.
Suitable for most prescriptions and can be coated to provide scratch resistance, ultra-violet protection and anti-glare qualities.

Polycarbonate

These lenses are thirty percent thinner and lighter than CR-39 and have the added benefit of impact-resistance.
All safety lenses certified by OSHA for use in the workplace are made of polycarbonate.
Offer better scratch-resistance than CR-39 and come with built-in ultra-violet protection.

Hi-Index

These lenses are by far the thinnest choice available. They are available up to forty percent thinner than CR-39 and are the best suited for high prescriptions.
Not as lightweight as polycarbonate nor impact-resistant, however, they come with built-in ultra-violet protection.
Can be treated to reduce glare and add scratch resistance.

Lens Styles

Single Vision

Lenses are designed to correct for hyperopia (farsightedness), myopia (nearsightedness) or presbyopia (needing reading glasses) all of which may include astigmatism.
Have the same focal power throughout (top to bottom).
Most people before the age of 40 wear single vision lenses.

Bifocal

Bi-focal

Has two separate viewing areas.
Top area is used for distance viewing (driving).
Bottom area is used for viewing close up (reading a map).
Have no peripheral (side) blur, however offer no intermediate vision (or range of vision).

Tri-focal

Have three different focus areas: the top for distance vision, the center for intermediate vision, and the bottom for near vision.
Extra focus area allows the wearer to view objects that are arms length away, about 20 to 25 inches from the eye (computer screen).

Progressive

Progressive (no line bi-focal)

Called progressives because they progressively get stronger from the top of the lens to the bottom where you read up-close.
Multifocal, good for viewing objects at all distances.
No visible lines like bifocals which betters your appearance.
Lenses are more like natural vision.

Premium Progressive (premium no-line bifocal)

Advances in design technology means a superior field of view.
Quicker adaptation by the human eye due to improved design.
Greater compatibility with premium AR treatments.