1 Has your child had a recent head injury or an injury to the eye?

2 Has your child suddenly lost all or part of his or her vision?

3 Has your child been suffering from double vision?

4 Is your child's vision blurred at all distances?

5 Are one or both eyes red and painful?

6 Is there a sticky, pus-like discharge, and is normal vision restored when the eye is cleaned?

7 Could your child have taken drugs prescribed for an adult or have eaten poisonous plants or fungi?

8 Does your child have difficulty seeing either near or distant objects?

9 Has your child been seeing flashing lights or floating spots?

10 Has this happened in the past, and has a severe headache followed?

11 Is your child taking any prescribed drugs?

12 Emergency! Call an ambulance

Possible cause A head injury can affect the part of the brain that is responsible for vision. A head injury resulting in a vision problem or an eye injury always requires immediate medical attention.

Action In hospital, the injury will be assessed and tests, such as skull X-rays and MRI scanning, may be carried out in order to determine the appropriate treatment.

13 Emergency! Call an ambulance

Possible cause and action Sudden loss of vision is always a serious symptom, even if it only lasts a few minutes or affects only one eye. Your child's eyes will need to be examined by a specialist. Your child may also be admitted to hospital for tests.

14

Possible cause A squint can cause double vision. This is because the images relayed to the brain from the eyes are not the same. If a squint is not corrected, the brain will suppress the image from one eye and vision will then fail to develop normally. Consult your doctor.

Action Your doctor will examine your child's eyes and will probably refer him or her to an eye specialist, who will explain the different treatment options used to correct a squint.

15 See your doctor within 24 hours

Possible cause Blurred vision may be caused by a discharge due to conjunctivitis, which is a bacterial infection. Your child's vision should be completely normal once the discharge has been gently cleared away from the eyes (see Coping with conjunctivitis).

Action Your doctor will probably prescribe antibiotic eye drops or ointment, which will need to be applied for several days.

16 Call your doctor now

Possible cause Iritis, inflammation of the coloured part of the eye, is possible.

Action Your doctor may refer your child to a specialist for an eye test and to look for associated disorders such as arthritis. If iritis is diagnosed, your child will need urgent treatment with corticosteroid eye drops or tablets to prevent permanent damage to his or her sight.

17 Emergency! Call an ambulance

Possible cause and action Poisoning caused by taking certain drugs, such as antidepressants, or by eating some types of plants and fungi can cause blurred vision. Carry out the first-aid measures for swallowed poisons while waiting for the ambulance to arrive.

18

Possible cause Longsightedness (difficulty seeing close objects) or shortsightedness (difficulty seeing distant objects) is likely. Consult an optometrist.

Action The optometrist will examine your child's eyes and check his or her vision (see Vision testing in children). Your child may need glasses.

19

Possible cause Migraine, recurrent severe headaches, may begin in childhood. This is especially likely if the condition affects one or both of the parents. Consult your doctor.

Action If migraine is diagnosed, your doctor may prescribe painkillers for your child to take during attacks. Try self-help measures for relieving a child's headache and for reducing the frequency of migraine.

20

Possible cause and action Certain drugs can cause blurred vision as a side effect. Call your doctor to ask whether you should stop giving the prescribed drug.

21

Possible cause A severe focusing disorder may cause blurred vision at all distances. Consult your doctor.

Action Your doctor will examine your child's eyes and will probably recommend that your child receives a complete vision assessment carried out by an optometrist Depending on the results, your child may need glasses and/or referral to a specialist for further treatment.

22

See your doctor within 24 hours if your child has a vision problem and you are unable to make a diagnosis from this chart.

23

See your doctor within 24 hours if your child has a vision problem and you are unable to make a diagnosis from this chart.