In this week's BMJ, senior eye doctors are warning people to keep liquid capsules for fabric detergents out of the reach of children after a wave of eye injuries in young children at their hospital.
Rashmi Mathew and Melanie Corbett from The Western Eye Hospital, Imperial College Healthcare NHS Trust in London report that last year chemical injuries associated with these capsules accounted for 40% of ocular chemical injuries in children under the age of five at their hospital.
They also report that Guy's and St Thomas' Poisons Unit received 192 enquires related to the capsules during 2007-8 and 225 calls during 2006-7, a fifth of which related to ocular exposure.
Of the 13 children they have seen recently, corneal burns resolved with no complications in 12 cases. However, one child received ocular irrigation (copious flushing of the eye with sterile water) only on arrival in accident and emergency and therefore sustained extensive corneal burns.
The capsule in most liquid detergent capsules is a water soluble polyvinyl alcohol membrane, explains co-author Katherine Kennedy, senior chemist at Guy's Toxicology Unit in London. The liquid detergent is a mixture of three active agents - an anionic detergent, a non-ionic detergent, and a cationic surfactant - dissolved in water to give an alkaline solution, making the capsule more dangerous than initially perceived.
The authors warn that alkali injuries are the most severe form of chemical eye injury which can cause irreversible damage and have lifelong ramifications, such as constant discomfort, scarring and even amblyopia (lazy eye).
They conclude: "After recent discussions with Guy's Poisons Unit, some manufacturers have made hazard labels more prominent. But greater consumer awareness is required to reduce injury. Such concentrated cleaning products must be kept out of the reach of children, and immediate irrigation is crucial to reduce the risk of clinically significant injury."