Lens tints and coatings
Tints
Solid tint - Most sunglasses have the same depth of tint over all of the lenses so that the world will look the same no matter which part of the lens you are looking through.
Graduated tint - these tend to have less tint at the bottom of the lens. As you generally need extra light for reading smaller print these can help with close work.
However. graduated tint is only available for lenses over 36mm (1⅖”) in height.
Mirror tint
This will give a touch of mystery to your glasses. They will stop people from seeing your eyes. Instead, they will see themselves mirrored in your glasses. Mirror coating come in gold, silver and blue.
Colour of tint
Sunglasses are generally tinted brown or grey. Grey tints seem darker but make the weather seem more overcast. Brown tints are lighter and make the world seem rosier . Obviously choose the tint which matches your frame colour.
Blue, yellow, pink or purple can be available at extra cost.
Photochromic
Photochromic coating - this turns dark, like sunglasses when you are outside in UV light. It returns to clear when you go inside. This means that you don’t need to carry around 2 sets of glasses, clear glasses and sunglasses, Available in brown or grey.
Unfortunately, you cannot tint polarized or photochromic lenses.
Depth of tint
Depth of tint - very pale (just a touch of colour – these are not useful as sunglasses), medium (useful in mildly sunny conditions), dark (useful for bright sunlight) very dark (only useful in extremely bright sunlight and not legal drive under normal conditions in the UK).
Blue blocking and polarized
Excessive exposure to short wavelength light (blue) may be damaging to your eyes. The biggest source of this light today is from digital screen such as smart phones and VDU screens. Blue light blocking lenses may increase your comfort when looking at screens for long periods of time.
Polarized lenses – these block light reflecting upwards from surfaces such as water, snow or roads. If you go fishing, for example, this means the dazzle from the surface of the water will be reduced, allowing you to see through the surface into the water. Polarized lenses are available in dark green or dark brown
Scratch resistant coating
This gives a much harder surface that is more resistant to scratching, whether from dropping your glasses on the floor or occasionally cleaning them with a paper towel.
Smudge resistant coating
This is a scratch resistant which repels water and grease. It reduces greasy smears which means you spend less time cleaning your glasses.
Anti reflective coating
This improves vision, reduces eye strain and makes your glasses look more attractive. These benefits are due to the ability of AR coating to virtually eliminate reflections from the front and back surfaces of your lenses but they can make greasy marks on your glasses more obvious.