This type of lens allows the wearer to focus on all distances, there being a gentle change from distance to intermediate to near focus as one looks through different parts of the lens. Progressive lenses provide more natural vision than bifocals or trifocals and are aesthetically more attractive. They are popular with people who think that the dividing lines in bifocal and trifocal spectacles 'make them look old'. Lens tints and coatings Tints are generally used for sun protection, although they can also be used simply for fashion purposes. Tints can be of almost any colour but grey tints are generally the best for preventing glare, as they do not distort colour perception.
Colour perception is particularly important when driving.
Lenses can be coated to reduce scratching. The coatings will help extend the life of a pair of spectacles, although no coating can prevent all scratches. If you purchase plastic lenses make sure that they have a scratch resistant coating. The extra light improves vision, particularly for older people. The reduced amount of reflection enhances the appearance of the spectacles, and is particularly effective in improving the appearance of higher powered lenses and high refractive index materials.