Single vision lenses are those that have the same focal power throughout the lens. They can be used to treat short-sightedness, far-sightedness or astigmatism.

The conventional stock lenses provide sharp view at the center of the lens, with some distortion in the peripheral areas. The lenses are fitted to the particular wearer and optimised for clear vision. Stock lenses are available in restricted power range only and are limited to frame sizes. While these lenses can be ideal for people that are short-sighted (minus powers), we recommend grind lenses for people that are long-sighted (especially high plus powers), that result in a thinner and lighter product.

Grind lenses are made with advanced optical design technology and are specially surfaced to the correct thickness for the dimensions of the frame. These lenses provide sharp view and minimal distortion in the peripheral areas. There are different lens technologies available to grind single vision lenses. Besides the standard grind lenses, CR Surfacing offers Digital and Digital Accuracy lens designs, that take single vision performance to the next level.

For general purpose, everyday wear, we recommend using Satin UV Anti-Reflecting Coating. Our Satin UV Anti-reflective coating is developed to improve vision by reducing glare, eliminate eyestrain by enhanced visual performance, protect your eye health by blocking UV rays, and enhance cosmetic appearance by cancelling out reflections on the lens surface. This coating also helps extend the life of the lenses. The Satin UV coating consists of layers specially formulated to create a scratch-resistant, water and dust repellent coat, making the lenses last longer. An ideal solution for everyday use, no matter the environment.

If you spend a lot of time on computers or digital devices, to give your eyes as much comfort as possible, we recommend to pair these lenses with Satin Blue coating. CR Surfacing’s special anti-reflective Satin Blue coating filters out harmful blue light coming from digital surfaces, as well as natural and artificial lights. Approximately one third of all visible light is blue light, a high-energy light that has a number of biological effects, including on the eye. Blue light penetrates all the way to the retina and can damage the light-sensitive cells and can increase the risk of age-related macular degeneration. Although not all blue light is bad, as it helps boost alertness, memory and cognitive function, the harmful wavelengths can be filtered out with Satin Blue coating, providing maximum comfort, enhanced visual performance and protection for your eyes.

Progressive lenses and the advantages of having them

Progressive lenses are no-line multifocal eyeglass lenses that look exactly the same as single vision lenses. In other words, progressive lenses will help you see clearly at all distances without those annoying (and age-defining) "bifocal lines" that are visible bifocals and trifocals.

Progressive lenses are line-free multifocals that have a seamless progression of added magnifying power for intermediate and near vision.

The power of progressive lenses changes gradually from point to point on the lens surface, providing the correct lens power for seeing objects clearly at virtually any distance.

Bifocals, on the other hand, have only two lens powers — one for seeing distant objects clearly and a second power in the lower half of the lens for seeing clearly at a specified reading distance. The junction between these distinctly different power zones is defined by a visible "bifocal line" that cuts across the center of the lens.

Progressive lenses sometimes are called "no-line bifocals" because they don't have this visible bifocal line. They have a significantly more advanced multifocal design than bifocals or trifocals.

Most people start needing multifocal eyeglasses sometime after age 40. This is when a normal aging change in the eye called presbyopia reduces our ability to see close objects clearly.

Progressive lenses also are the lens of choice for anyone who needs corrective lenses to see distant objects clearly (due to nearsightedness, farsightedness and/or astigmatism) and for those who are presbyopic.

For anyone with presbyopia, progressive lenses have significant visual and cosmetic benefits compared with traditional bifocals and trifocals.

As already mentioned, bifocals have just two powers — one (in the top half of the lens) for distance vision, and a second (in the lower half of the lens) for near vision.

Trifocals go one step further — they have a third power for seeing objects clearly at arm's length. This "intermediate" power of a trifocal lens is located in a thin horizontal zone between the distance and near power zones.

Progressive lenses, on the other hand, have many more lens powers than bifocals or trifocals, and there's a gradual change in power from point to point across the surface of the lens.

The multifocal design of progressive lenses offers these benefits:

• It provides clear vision at all distances (rather than at just two or three distinct viewing distances).

• It eliminates "image jump" caused by bifocals and trifocals. This is where objects abruptly change in clarity and apparent position when your eyes move across the visible lines in these lenses.

• Because there are no visible "bifocal lines" in progressive lenses, they give you a more youthful appearance than bifocals or trifocals. (This may be the reason why today more people wear progressive lenses than the bifocal and trifocals combined.)