Moral of story: If your 10-year-old wants to dye their hair, don't stand around arguing about the color. Help them do it safely.
[Accidental staining of corneal nerves by methylene blue.]
[Article in German]
A 10-year-old child presented after accidental exposure of the left eye to a blue hair dye containing methylene blue. Mild ocular surface changes and a selective blue staining of the usually invisible corneal nerve fibre bundles were present. Corneal sensitivity was reduced. Despite copious lubrication a transient neurotrophic keratitis developed which did not resolve until corneal sensitivity became normal 2 weeks later. Association of mild chemical burns with neurotrophic keratitis is unusual but is of high clinical relevance as keratitis is a vision-threatening complication.
Peter S, Reichart E, Poyntner L, Mennel S.
Abteilung für Augenheilkunde, Landeskrankenhaus Feldkirch, Carinagasse 47, 6800, Feldkirch, Österreich, Silvia.Peter@LKHF.at.
I've always thought there might be reduced sensation on the eye surface for children who've got surface changes from eyedrops eg with BAK. I think this because despite dry eyes, my daughter can outstare anyone by a long way and we've always had the problem that after blitzing with random prescribed meds for 1y from age 11 when the ophth didn't know what it was, she didn't feel discomfort very much despite the damage so didn't drop enough. Now much better at age 15 she feels dry eye more like an adult.
The paed ophth say it's because children don't complain about pain like adults because they don't know what's normal and just go along with it, ie they don't necessarily say 'there's something wrong with my eyes'. Eg they might remove a bandage contact lens after surgery and there is infection and inflammation, whereas an adult would have known immediately there was a problem.
But a small degree of neurotrophic keratitis from chemicals in eyedrops sounds like our experience. This is also about formulating eyedrops for children's eyes, smaller area and more sensitive and absorbent, I guess, like their skin. And the age-old problem of working out how adult meds affect children, which is sometimes very differently.