Eyeglass Lenses and Coatings: The Basics
Lens manufacturers have some innovative offerings that can make your eyeglasses more durable and lightweight. But they can also add to the price. Here’s an overview of lens materials and coating options:
• Composite lenses: These light, durable lenses are appropriate for most eyeglass wearers. They include polycarbonate, Trivex, and other materials.
• Plastic lenses: Standard, mid-index, and high-index plastic lenses have varied features. Standard plastic lenses are widely prescribed because they are affordable, lightweight, and durable. Mid-index and high-index options allow you to maintain thinner lenses as your prescription gets stronger.
• High-definition: These thin, lightweight lenses are customized to your eyes by using digital computer technology and diamond-cutting tools, and are suitable for all prescriptions. They can add about 25 percent to the cost of your lenses.
• Photochromic coatings: Glasses with this coating automatically darken to act as sunglasses when exposed to light, protecting the eye from ultraviolet rays.
• Anti-glare: This coating eliminates “ghost images” and halos during situations like night driving.
Alan Glazier, M.D., an optometrist and founder of Shady Grove Eye and Vision Care in Rockville, Md., says getting accurate lenses requires your optician to make a series of measurements that include:
• Pupillary distance, or PD—the distance between the bridge of the nose and each pupil—which often varies among individuals because most people’s faces aren’t symmetrical. If a lens’s optical center isn’t properly aligned over the pupil, you may experience “prismatic effect,” causing your eyes to work harder.
• Eye size, the width of your nose bridge, and temple length.
Learn more about how to prevent falls after getting new eyeglasses.