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.

There are several health-related effects of blue light emitted from screens, such as:

• During the day, you may experience visual tiredness;

• At the end of the day, you'll have headaches;

• Having trouble falling asleep and having sleepless nights;

• Retinal degeneration is more likely.

• Increased vulnerability post-cataract surgery.

Blue cut lenses block 40% of this hazardous light thanks to a filter added to these glasses. This filtration is more than enough to restore proper blue light levels reducing adverse effects. Wearing blue light filter glasses protects your eyes as well as your health!

What are photochromic lenses made of?

Photochromic lenses are made of molecules composed of trace amounts of silver chloride (the same chemical compounds used to develop film). When this silver chloride is exposed to ultraviolet light, the molecules become silver metal, allowing the lenses to absorb visible light and turn darker in the process.

Unlike film exposure, photochromic lenses are also made with copper chloride, which strips the silver of its chloride electron. This allows the lenses to return to their original, non-absorbing state in the absence of ultraviolet light.

More modern photochromic lenses often contain organic molecules called naphthopyrans instead of silver chloride. Naphthopyrans change their molecular structure when ultraviolet light strikes them, making the lenses darken.

The difference between photochromic and Transitions lenses

The difference between photochromic lenses and Transitions lenses is that Transitions is a brand of photochromic lenses — one of several brands.

Photochromic lenses are also often referred to as transition lenses (lowercase t), hence the understandable confusion.

Let's take a closer look at the differences:

Photochromic lenses

Traditional photochromic lenses are made of plastic, glass or polycarbonate and change from transparent lenses to darker lenses when exposed to sunlight.

There are several terms used to describe photochromic lenses, including light-adaptive, light intelligent, variable tint and transition lenses.

Photochromic lenses are available in virtually all lens materials and in a variety of tints made for general-purpose lenses as well as contact lenses. Some sunglasses manufacturers even make tinted lenses that go from dark to darker shades rather than from clear to dark.