Plastic vs. Glass Lenses in Glasses

Picking out new glasses is exciting. Because today's optical stores offer so many choices in style and price, it can also be a bit daunting. In addition to selecting from the vast array of frames offered, you must decide what type of lenses to wear. Plastic, according to the Cleveland Clinic, is the most popular lens material. To make your decision easier, however, just keep four basic things in mind.

Weight

• Glass lenses weigh about twice as much as plastic lenses. The more nearsighted or farsighted you are, the stronger your prescription will be and the heavier your lenses will be. Larger frames require more lens material, which also adds to the weight. For minor vision corrections in a small frame, the difference is minimal.

Thickness

• Plastic lenses are slightly thicker than glass lenses. The thickness is determined by the index of refraction, a number that indicates the speed of light through a material and how it is affected by the density of the material. Your prescription is calculated the same in each material but is slightly different in glass and plastic.

Durability

• Plastic is much more shatter-resistant than glass lenses but glass is more scratch-resistant. Although plastic lenses are usually covered with a scratch-resistant coating, the material is much softer and easier to scratch. Neither material is totally scratch-proof.

Considerations

• Both glass and plastic lenses are available in a variety of colors, including lenses that get darker outside and lighter indoors. Only plastic lenses can have color added to them or taken out. Color in glass lenses is permanent.