One complication of standard eyeglasses is that their lenses can reflect light from both the front and back surfaces, reducing clarity and brightness of the things you see. But anti-reflective lenses increase light transmission to as much as 99.5 percent—a significant difference that’s especially helpful under challenging lighting conditions such as viewing computer screens or driving at night. Anti-reflective lenses also make your eyes more visible to others, improving eye contact—one of the most important communication tools people possess.
Bifocal, Trifocal and Progressive Lenses
Bifocals are a clever invention which allows you to wear two pairs of glasses at the same time. The main lens allows the wearer to focus on distance objects, while the smaller lower lens is designed for reading. Typically, the lenses are separated by a visible line in the glass. In the same manner, trifocals allow for three reading distances with the inclusion of a center section which focus on objects at roughly arm’s length. This also means that trifocals have two lines separating the three sections of lens.
Lined bifocal and trifocal lenses can cause issues while viewing near the lined areas. But newer multifocal lenses, called progressive lenses, minimize the visual interruptions caused by traditional lined lenses, which makes for clearer viewing and reduced eye strain. They also allow for larger reading areas and easier adaptation when moving from close-up vision to distant viewing.
High Index Lenses
Traditional lens materials such as glass and hard resins have a down side: they can be heavy and thick. Newer “high index” materials help solve this problem; because they have a higher index of light refraction, they focus light more powerfully than the same amount of traditional lens material. The advantage is that high-index lenses can be made thinner and lighter, which makes eyeglasses using high-index lenses more comfortable and attractive to wear.
Photochromic Lenses (Transition Lenses)
Photochromic lenses solve the problem faced by anyone going from indoors to outdoors on a sunny day—they automatically become sunglasses. It’s a clever trick performed by photochromic molecules embedded in the lenses which react to ultraviolet light. Photochromic lenses offer a range of colors and strength of tint, so it’s possible to tailor them to your specific needs; you can choose a darker tint if you spend a lot of time outside, for example. Photochromic lenses have some limitations: they don’t transition instantly from one state to the other, and they might not be ideal when driving since a car’s windshield will absorb most UV rays before they reach your glasses. But photochromic lenses are a great option if you’d rather not switch frequently between two sets of glasses.
Polarized lenses allow fishermen to see beneath the surface of lakes and streams. They can also make driving safer and more comfortable by reducing glare from pavement or oncoming vehicles.
Scratch Resistant Coating
High-index lenses have many advantages, but they’re not as scratch-resistant as glass. Scratch-resistant coatings help minimize this issue; by preventing scratches, they help your lenses perform and look better. Scratch-resistant coatings typically include a warranty to further extend your investment. While all lenses can be scratched, scratch-resistant coatings will greatly extend the life and appearance of your lenses.