Kids' sunglasses: why children's eyes take in more UV than yours
Eye health, 5 min read, August 2026
We protect children's skin without thinking about it. Their eyes, far less, even though they are more exposed and less well defended than an adult's.
The human eye has a natural filter against ultraviolet light: the crystalline lens, the internal lens that handles focusing. In an adult, that lens has clouded with time and blocks a significant share of UV before it reaches the retina. In a child, it is still very clear.
The accepted orders of magnitude leave little doubt. A child under ten transmits a far higher proportion of UV to the retina than an adult does, and that proportion drops gradually over a lifetime. In other words, the same hour spent in the sun does not have the same effect at seven as it does at forty.
Why it matters more in the tropics
Three factors stack up near the equator. The sun sits high, so its rays cross a thinner layer of atmosphere. The UV index stays high for much of the year. And sand, water and pale concrete reflect a large share of the radiation upwards, which reaches the eye from below, exactly where a hat offers no cover.
A child playing for three hours on a beach therefore takes direct UV, UV scattered by the sky and UV bounced back by the sand. It is the most demanding situation there is, and it is also the most common one in Bali.
The toy sunglasses trap
This is the most important point in this article. Tinted glasses without certified UV protection are more dangerous than no glasses at all.
The reason is mechanical. In bright light, the pupil contracts to limit what comes in. Behind a dark lens the eye believes it is in the shade, the pupil opens up, and if the lens does not filter UV it lets in more ultraviolet than the naked eye would.
Glasses sold at markets, in souvenir shops or as costume accessories often fall into this category. The tint is a dye, not a filter.
"A dark lens with no UV filter opens the door instead of closing it. It is the only case where a pair of glasses makes the problem worse."
What to check before buying
The UV400 marking, or a "100% UV" claim with the matching standard. This is the one non negotiable criterion. It means the lens blocks radiation up to 400 nanometres, which covers both UVA and UVB.
The tint category. For everyday outdoor use in strong sun, category 3 is the reference. Category 4, very dark, is meant for high mountains and is not advised for general use. Categories 0 and 1 are decorative and not enough in full sun.
Coverage. A wide lens with a slight curve, sitting close around the eye, limits what comes in from the sides. That matters especially for children, whose faces are small and whose eyes are constantly on the move.
The frame. Flexible, with no aggressive metal parts and a hinge that forgives. Children do not handle their glasses delicately, and a frame that breaks on the first knock will never be worn.
Getting children to accept their glasses
This is the real obstacle, far more than the technical choice. Three things genuinely help.
Let the child pick the colour and the shape. A chosen pair gets worn, an imposed pair ends up in the bag.
Start with short sessions at a pleasant moment, rather than in the middle of the beach at noon when everyone is already on edge.
Use a cord for the youngest, and a hard case from day one. A pair lost on the first day protects nobody.
And babies
Before the age of one, shade remains the best protection: pram hood, wide brimmed hat, avoiding direct exposure between 10am and 4pm. Sunglasses become genuinely useful once the child walks, goes out in the sun alone and accepts keeping them on.
Try them on in store: our teams fit children's frames and check their protection, addresses on Maison Mata Stores in Bali.
This article is informative and does not replace medical advice. For any question about your child's eye health, consult a healthcare professional.