Why are sunglasses important?
As well as sunglasses improving eye sight they also prevent the sunlight from reaching our eyes. Sunglasses are a easy and efficient way of preventing harmful ultraviolet light from reaching our eyes also. Ultraviolet light is responsible for many harmful burns such as sun burn on our skin and if it can burn our skin it can cause similar damage to our eyes. It doesn't have to be sunny and warm to get sun burn and its the same with with our eye.
Ultraviolet light can damage our eyes in many different ways including a temporary but painful burning of the eye surface and cataracts (clouding of the lens) however it does cause harm to the surrounding areas of the eye. Too much sun or extreme sun exposure can cause skin cancer which will affect the eyelids and the skin around the eyes.
What to look for in sunglasses?
To get the best protection from potential UV damage you should check that the sunglasses are labelled with UV 400 and a piece of paper that state that the sunglasses offer 100% UV protection. An important notice to take on board is that even if the lenses are dark it doesn't mean that they have a better protection against UV light. Lens coating such as Crizal Forte UV from Essilor provide UV protection without any tint at all, so it is possible to have glasses that are better at protecting your eyes from the UV light than sunglasses without UV protection. Some experts say that wearing ordinary sunglasses without any UV protection may be worse for your eyes than wearing nothing at all. This is because the dark lenses cause the pupils to open wider which essentially let in more harmful UV light.
When should they be replaces/do they stop working?
The sunglass protection does not reduce over time however if you have had additional coating put over our lenses such as anti-glare coating that can come off the lens if they become scratched. As long as you've properly looked after your sunglasses they can last a very long time.
Are all sunglasses as good as one another?
If you have purchased a pair of adequate protection sunglasses from UV damage then they are doing their job properly. However taking into consideration of the clarity of vision that you can get from looking through the lenses there are a few things to look out for such as;