Unit of lens refractive power, equal to the reciprocal of the lens focus length in meters.

The clarity or sharpness of vision measured at a distance of 20 feet.

A way to measure chromatic aberration in lenses.

Anti-reflective coatings improve the quality and the value of your lenses. An anti-reflective coating reduces disturbing reflections. It makes your lenses more attractive. And you will experience the most precise, crisp and clear natural vision in a brilliance that is not possible with uncoated lenses.

Safety standards that must be met for glasses to be considered safety glasses

A misshape of the eye, where vision is blurred by an irregularly shaped cornea. The cornea, instead of being shaped like a sphere, is ellipsoidal (like an egg) and reduces the cornea’s ability to focus light.

Indicates the placement in degrees of the astigmatic lens.

Polycarbonate lenses

Involves high velocity projectiles. Ballistic eyewear

The curve on the back surface of the contact lens.