It’s as important to block ultraviolet rays from your child’s eyes as it is to block it from their skin, so buying them a pair of sunglasses is probably a good idea – and often if you let them help to pick the ones they want it will make life easier when trying to get them to wear them.
You must make sure that when you are buying sunglasses that the product confirms they block out UVA and UVB rays to ensure you are getting the right level of protection. Without this protection the darkened glasses will simply cause the child’s pupil to dilate which will cause even more damaging rays to get at the eye. The shade of glass is a personal choice, but something of a medium darkness is often the best choice, so that it gives enough protection from the glare without being so dark it would cause the pupil to dilate which allows more UV rays to enter. It is not the colour of the glass that offers the protection.