Spectacle Lens Technology

Consumers today have an amazing selection of lenses to choose from. Technology has given us lenses that darken and lighten according to lighting conditions, thinner, lighter lenses, coatings that are easy to clean, and lens designs that maximize the clear viewing area on the lens. Our doctors and staff attend industry seminars to keep current about the newest products and we are able to help you find the right lenses for your prescription, your needs and your budget.

There is a lot to know about lenses. The following information will help get you started.

Lens Materials

Lens Material

Standard plastic is the most common lens material. It has a refractive index of 1.50, is lightweight, durable, and has excellent optics. It can be made with a number of different coatings and tints and is a good all-around choice.

High index plastics are thinner, lighter lens materials suitable for higher prescriptions. The refractive index can range from 1.60 to 1.74, depending on your needs, with a higher index material resulting in a thinner lens. They can also be tinted and coated.

Glass is an old favourite for some people. It has excellent optics and is naturally scratch resistant. However, compared to other materials, glass is significantly heavier and breaks more easily, so it has been used less often in recent years.

Polycarbonate is sometimes offered under different trade names. It is a light, tough material with a refractive index of 1.58. However, its optical qualities are not as crisp as other materials, meaning that your vision may not seem as clear with polycarbonate lenses. Polycarbonate also scratches more easily than other materials. Because of this, we generally do not recommend polycarbonate.

Lens Types

Single vision lenses provide one power only, for the correction of nearsightedness, farsightedness and astigmatism.

Bifocal lenses are designed with a distance power at the top of the lens and a reading power in the lower part of the lens. Bifocals have a visible line.

Trifocal lenses have a distance power at the top, a reading power at the bottom, like bifocals, but they also have an intermediate power in between. Trifocals have two visible lines.

Progressive lenses also have distance powers at the top and near powers toward the bottom. Unlike bifocals and trifocals, the powers are blended together, so progressives have no line.  

Computer lenses are designed to improve clarity and visual comfort for prolonged computer use. They may be a special type of progressive lens, a bifocal lens, or a single vision lens depending on your needs.

Coatings and Tints

Scratch resistant coatings make the lenses more durable. This coating is often standard on plastic lenses.

Antireflective coatings reduce the light reflected from the lenses. This improves light transmission for a clearer, more comfortable lens.

Photochromic lenses have built in tints that darken and lighten, depending on lighting conditions. Transitions is a brand of plastic photochromic lenses, with different types of tints for different applications. Drivewear is another brand of plastic photochromic lenses, and it is designed as a sunglass lens for driving.

Polarized lenses are sunglass lenses that are tinted in a way that blocks reflected light and reduces glare.

As an independent clinic, we are able to offer lenses from many manufacturers. We usually prefer Nikon lenses because of their high quality products and excellent service.

Trust us to help you make the right choice for your needs!