Eyeglass Lenses

 

Today’s lens technology offers many options, allowing your new lenses to be customized to your individual lifestyle. While this may seem complex, we are here to help. The experts at Triangle EyeCare will take their time to educate you and answer any questions you may have.

Lens Design

Lenses may be either be single vision (one prescription only) or multifocal (bifocals, trifocals and progressive lenses). Progressive (no line) lenses provide a gradually changing prescription so vision is clear at all viewing distances.

Lens Material

Although lenses were originally made of glass, nearly all of the lenses used today are some form of plastic. Today’s plastic lenses are extremely scratch resistant, and are much thinner, lighter, and safer than glass. Lens materials include CR-39 plastic, polycarbonate, Trivex, and various high index choices. We will consider your prescription as well as your lifestyle when recommending the best lens for you.

lens Treatments

There are many lens treatments available that can make your new glasses the best ever. Anti-reflective lenses are nearly always used. By reducing glare, you will both see and look better. Some other options include scratch resistant coatings, UV protection, and polished edges. Some treatments may be included with certain materials.

Lens Tinting

We offer many different tint options ranging from light cosmetic tints to dark tints used in sunglasses. Transitions® lenses adjust the level of tint automatically based on the level of sunlight. Polarized lenses reduce glare, providing safe and relaxed vision.

Lens Designs

Single Vision: These are lenses with one prescription strength. If you only struggle with distance (or close up) vision, you likely need single vision lenses.

Multifocal (bifocal & trifocal): These lenses correct more than one field of vision. They are used for people with presbyopia who need additional prescription to see up close. Bifocals provide two zones; a distance, and a near reading. Trifocals provide three zones; distance, an intermediate zone (such as computer), and near reading. The zones are divided by a visible line. Many find it challenging to switch form one focusing power to another as they are separated by a hard line.

Progressive Lenses: One of the main problems with traditional bifocal and trifocal lenses is the problem of eye fatigue. It can be challenging to switch from one focusing power to another when it is separated by a hard line. This can make your eyes tired, and it can even lead to a headache, sore neck, and sore back. Progressive lenses allow the eye to change focus smoothly between distances without visual jumps which occur when crossing the line in a bifocal or trifocal. A gradual change in power allows the wearer to focus on objects at all distances. An excellent choice for computer users, they are also more flattering as they lack the visible line.

 

 

 

 

 

Lens Materials

 

CR-39 Plastic: Introduced in 1947 as the first light weight eye glass lens (about half the weight of glass), it has low cost and provides excellent optical qualities. They can be tinted almost any color. CR-39 is more impact resistant than glass, however can scratch more easily. Addition of an optional scratch resistant coating is recommended.

Polycarbonate: In the early 1970’s, the first polycarbonate lenses were introduced for use in safety glasses developed for helmet visors for the Air Force. Polycarbonate is lighter and significantly more impact-resistant than CR-39 plastic. It is the lens of choice for sports eyewear, safety glasses, and eyewear for children. They absorb harmful UV light, and can be made ultra-thin because of it’s unique strength.

High Index Lenses: In response for the demand for thinner and lighter lenses, several new high index lenses have been introduced. Optically, they can do the same job as CR-39 or polycarbonate lenses, but with less lens material. The higher the refractive index of a lens material, the less material is required, and the thinner the lens will be. Three different high index materials are commonly available.

Lens Treatments

Scratch Resistant Coating: all plastic lenses require a factory-applied anti-scratch coating for adequate lens durability. Modern anti-scratch coatings make your lenses nearly as scratch-resistant as glass and provide a one year warrantee. With modest additional cost, scratch resistant coating should be considered essential. Many high index lenses provide scratch resistant coating standard.

Anti-Reflective Treatment: Performance of all lens materials can be enhanced with anti-reflective (AR) treatment. Eliminating reflections in the lens and increasing contrast and clarity, AR is particularly effective at reducing eye fatigue when driving at night or operating a computer. They also improve your look as your lenses are nearly invisible. AR is especially important when using high index lenses. The higher the lenses refractive index, the more light it will reflect. Some high index lenses can reflect up to 50% more light than a CR-39 lens. This will result in significantly more glare unless an anti-reflective treatment is applied.

UV Protection: Harmful ultraviolet (UV) radiation has been associated with eye problems including cataracts and macular degeneration. Polycarbonate and nearly all high index lenses offer built in UV protection at no additional cost. However, if choosing a CR-39 lens, this coating must be added to provide the level of UV protection that comes standard on polycarbonate and high-index lenses.
Edge Polish: For thicker lenses, the edge may be polished to make it appear smooth and shiny. Semi-rimless and rimless frames should have their edges polished because the edge of the lens is exposed.

Mirror Coating: A mirror lens coating applied to the outside of a lens and helps to deflect light and keep it from entering the eye. The outside of the lens looks just like a mirror, however the wearer does not see the mirror coating from the inside. For example, if the lenses had a brown tint with a blue mirror, the wearer would see only brown, and other people would see only the blue mirror. It especially useful for conditions of sand, water, and snow.

 

 

 

 

 

 

 

 

 

 

 

Lens Tints

 

 

 

 

 

 

 

 

 

 

Sunglass lenses are tinted to cut down on overall brightness and enhance definition. For activity in bright sunlight you need a sunglass tint color that blocks most of the light such as brown, green, or gray.
Each group or range of colors has a special application that improves clarity and contrast in a variety of settings.

Yellow/Orange: Yellow and orange tints increase contrast in hazy, foggy or low-light conditions. These tints tend to make objects appear sharper both indoors and outdoors, but can also cause color distortion. Choose yellow shades for snow activities and indoor ball sports.

Green: Green tints filter some blue and reduce glare, while offering high contrast and visual sharpness. Shades of green also tend to reduce eyestrain in bright light. Choose green for precision sports such as tennis, baseball and golf.

Amber/Brown: Amber and brown tints reduce glare and block blue light, giving them the ability to brighten vision on cloudy days. By blocking blue light, these tints increase contrast and visual acuity, especially against green and blue backgrounds such as grass and sky. Choose amber and brown tints for fishing, baseball, golf, hunting, cycling, and water sports.

Rose/Red: Rosy tints increase contrast by blocking blue light. These tints have a reputation of being soothing to the eyes and more comfortable than others for longer wear-times. They also help with visibility while driving, and seem to be a favorite among computer users as they reduce glare and eyestrain.