Sunglasses for children are often treated as an accessory. There are two reasons to take them more seriously than that, and both are about biology rather than fashion.
Children get more exposure
The first is straightforward: children spend more time outdoors than most adults, and they do it in the middle of the day. A meaningful share of a person’s lifetime ultraviolet exposure is accumulated before adulthood, simply because that is when people are outside the most.
Their eyes filter less of it
The second is less obvious. The lens inside the eye yellows gradually with age, and in doing so it absorbs more ultraviolet. A child’s lens is clearer than an adult’s, which is good for their vision and means more ultraviolet reaches the back of the eye. Their pupils also tend to be larger, which lets in more light again.
The practical upshot is that the same afternoon in the sun does not deliver the same dose to a six-year-old as to a forty-year-old.
What to look for
- The ultraviolet specification, not the tint. UV400, or a statement of 100% UVA and UVB filtering. A dark lens without it is worse than nothing, because it opens the pupil and lets more ultraviolet through.
- Impact-resistant lens material. Polycarbonate is the usual choice and is standard in children’s eyewear for obvious reasons.
- Flexible frames. Nylon and similar polymers bend and return rather than snapping. They will be sat on.
- A strap or band for the youngest. Glasses that end up in the sand get abandoned.
- Coverage. A slightly wrapped frame blocks light coming in from the sides, which a small flat lens does not.
Getting them worn
The most protective pair is the one that stays on a face. Comfort and the child’s own choice of colour do more for compliance than any specification. Adults wearing sunglasses helps too, since it makes them normal rather than a rule.
Hats deserve a mention: a broad brim cuts a substantial share of the ultraviolet reaching the eyes, and works well alongside sunglasses rather than instead of them.
Keeping it in proportion
This is not a reason to keep children indoors. Outdoor time is good for developing eyes, and there is reasonable evidence that time spent outside is associated with lower rates of short-sightedness in children. The sensible position is straightforward: let them be outside, and give them decent sunglasses and a hat while they are.
If you have specific concerns about a child’s vision, an optometrist is the right person to ask.
