The Eyecare Trust estimates that half of parents who have children under the age of eight have never taken them for a sight test.
It states even in the present economic climate parents should book their children in for an appointment with an optician - and reminds them eye tests for the under-16s are free.
Trust chairman Iain Anderson said: "It"s vital we encourage more people have regular sight tests - generally once every two years unless advised otherwise by your optometrist."
David Cartwright, director of professional services at Boots Optician, described how children"s vision can be permanently affected if they have a condition that goes untreated.
These included lazy eye (amblyopia), which can be corrected if it is caught early enough but can cause lifelong problems if it is not.
While children under eight years old are often considered too young to have contact lenses, older ones can be taught how to clean and put them in by themselves.
by Martin Burns