Younger children are often unaware that they have a problem with their vision, so the only noticeable symptoms of a lazy eye may be related to an underlying condition, such as:

• a squint - where the weaker eye looks inwards, outwards, upwards or downwards, while the other eye looks forwards
• childhood cataracts - which are cloudy patches that develop at the front of the eye (the lens)
• ptosis - which is where the upper eyelid drops over the eye, impairing vision

One way to check your child's eyes is to cover each eye, one at a time, with your hand. If they try to push your hand away from one eye, but not the other, it may be a sign they they can see better out of one eye.

Another sign is your child having problems with their depth perception. Due to the mismatch between each eye, children with lazy eyes have difficulty judging how far away objects are.

Signs to look out for include:

• being unusually clumsy for their age, such as running into furniture or falling over a lot
• problems catching a ball
• poor performance in sports

Older children may complain that their vision is better in one eye and that they have problems with reading, writing and drawing.

When to seek medical advice

Many cases of lazy eye are diagnosed during routine eye tests before parents realise that there is something wrong with their child's vision.

If you are concerned, visit your GP, who can refer your child for further testing by an eye specialist (ophthalmologist).