Case study

Toby Smith was just five when his mother, Sarah, a teaching assistant, noticed him turning his head to one side when they were looking at flash cards. Asked why, "he said he couldn't see anything out of his left eye and only dots out of his right".

Within days, an ophthalmologist at a hospital in Norwich told Sarah and her husband Robin that Toby had a rare inflammatory eye disease called uveitis. "I was," says Sarah, "in complete shock."

Toby is now 12 and the condition is kept under control by eye drops. Although his left eye sees only light and shade, he wears bifocals that make the vision in his right eye almost normal.

"If we had found out earlier he may have had more vision," says Sarah. "Don't wait until your children are five to take them for an eye test."

Rosie Auld, chairman of the British and Irish Orthoptic Society, says parents should ensure that their children receive vision screening between their fourth and fifth birthdays. Orthoptists specialise in children's conditions, and are ideally placed to lead local screening teams. All children under the age of 16 are entitled to a free NHS eye test so, if orthopticled screening is not available, they can take their child to see a optometrist.

Geoff Roberson, from the Association of Optometrists, added: "Good eye health ensures a child develops socially and academically to the best of their ability."

Short sight, long sight and astigmatism should be picked up and corrected by glasses.

It is vital that squint, or strabismus, a condition suffered by 5% of children is diagnosed early. If not picked up and corrected before the age of eight, a squint can result in permanent sight loss as the brain "turns off" one eye, a condition known as lazy eye, or amblyopia. Treated in time, the condition is easily corrected with prescription glasses or, in some cases, by patching the good eye to make the lazy one work.