Spectacle lens spectacular

April 15, 2011

What is in your lens toolbox?

Key Points

What is in your lens toolbox? Each "shelf" and "drawer" should contain many types of lenses: digital lenses, high-index lenses, impact-resistant lenses, polarized and photochromic lenses, and occupational lenses.

Digital lenses

Who are these lenses suited for? The answer is: everyone. Although these lenses can be pricey, isn't your patients' vision worth it? Simply ask them if they want the most advanced technological lens design available.

High-index lenses

We have come a long way since crown glass, CR-39, and Hi-Lite Glass were the only lens material options. Dispensers now have polycarbonate, mid-index plastic, high-index plastic, and super high-index plastic available for patients who are interested in thinner, lighter lenses.

When do you begin thinking high index? Right after you ask your patients if thickness is an issue with them. Most people do not want to sport thick lenses.

Have a nice lens display, depicting several different lens powers in all the index of refraction lens materials. Be sure to tell patients that the thinner a lens is, the lighter it'll be. Obviously, the high-index lenses are a savior for your patients with really high lens powers.

Be sure to know the power range in which lens materials are available. For instance, the power range is higher for minus-powered lenses than plus powers.

As for weight considerations, the lower the specific gravity (grams per cubic centimeter) the lighter the lens will be. One last consideration is the Nu Value of the lens. This number represents how much chromatism a lens will have. Chromatism is the breaking up of light into its component colors. Think how a prism or crystal shines rainbows on a sunny day. The same thing can happen when the Nu Value is low, and this can detract from clear vision.

Impact-resistant lenses