A knock to my child's head: when the eyes need checking after a bump or concussion
A fall off the bike, a football to the head, a collision at school. The signs that mean emergency care now, what blurred or double vision can mean afterwards, and why reading feels hard for a while.
Go to emergency care now, not an eye appointment, if…
- A concussion does not need a loss of consciousness (AAP). A child who stayed awake can still have one, so a knock that leaves a child dazed or clumsy is worth a doctor's look.
- Emergency care comes first: seizure, repeated vomiting, a worsening headache, drowsiness, unequal pupils, double vision, clear fluid from the nose or ears, or a baby who will not settle.
- Blurred vision, double vision and light sensitivity are common symptoms. In a clinic sample of 100 teenagers, 69% had a vision diagnosis after concussion, mostly focusing and eye-teaming problems.
- The AAP advises cutting back physical and mental activity for the first 48 to 72 hours, with a stepwise return. A child does not need to be symptom-free to return to school but should manage 30 to 40 minutes of activity.
- An eye check helps when reading, focusing or tracking trouble persists at school. Start with the doctor looking after the concussion and ask about an eye referral.
A fall off the bike, a football to the head, a collision in the school corridor. Your child says "I'm fine", rubs the spot and goes back to playing. An hour later the eyes look different, or the screen is too bright, or the words on the page will not stay still.
This page puts the order of questions right. First, the signs that mean emergency care now and not an eye appointment. Then what a concussion can do to the eyes, how school and screens usually go, and when an eye check helps. I look after children's eyes, not their brains, so the concussion itself is managed by the doctor who assesses your child. My part is the eyes.
What counts as a concussion, and does my child need to have been knocked out?
A concussion is a mild brain injury from a bump, blow or jolt to the head, or from a hit to the body that makes the head move sharply back and forth. Your child does not need to have been knocked out. The American Academy of Pediatrics (AAP) says loss of consciousness is not necessary for a concussion.
So a child who stayed awake the whole time can still have one. A knock to the head that leaves your child dazed, clumsy or unlike themselves is a reason to have a doctor look, even if there is no mark on the skin.
Which signs mean emergency care now, not an eye appointment?
Go to the nearest hospital emergency department or call an ambulance (999) if, after a head injury, your child has a seizure, vomits repeatedly, has a headache that keeps getting worse, becomes very drowsy or cannot be woken, loses consciousness even briefly, or does not recognise people or places. Do not book an eye appointment for these.
Two eye-related signs belong on the same list. The US Centers for Disease Control and Prevention (CDC) lists one pupil larger than the other, or double vision, among its emergency danger signs. NICE, the English guideline body, lists clear fluid running from the ears or nose, and a black eye with no direct injury around the eye, among the signs of a possible skull fracture. Slurred speech, weakness, numbness or poor coordination also need emergency care. Walk through that list before anything else on this page.
What about a baby or toddler who bumps their head?
For a baby under one year, any concern after a head knock deserves a doctor the same day, and some signs mean the emergency department. NICE advises that anyone with concerns after a head injury seek medical advice whatever the severity, and it lists a bruise, swelling or cut larger than 5 cm on a baby's head as a reason for a scan.
A baby or toddler cannot tell you about a headache. CDC lists a child who will not stop crying and cannot be consoled, or who will not nurse or eat, among its danger signs. NICE adds changes in feeding or sleeping, listlessness and loss of interest in things around them. A baby who will not settle after a knock is a baby to take to the emergency department.
If the knock seemed minor, what should I do in the first 24 hours?
Keep a responsible adult with your child for the first 24 hours, and have the child seen if you are worried at all. NICE says a responsible adult should stay with a child for the first 24 hours after a head injury, and that some people seem to recover quickly but have difficulties later. It also lists a headache that does not go away, any vomiting, memory gaps about the injury and unusual irritability or changed behaviour among the reasons to be seen in an emergency department.
That is a lower bar than the emergency signs above, and deliberately so. If you are unsure which side of the line your child is on, ask. A call to the clinic or the hospital emergency department costs you a few minutes, and a missed sign costs far more. Watch the eyes too: a pupil that looks bigger than the other, or a child who suddenly says things look double, moves the situation to the emergency list.
What can a concussion do to my child's vision?
Blurred vision, double vision and sensitivity to bright light are common after a concussion. The AAP says older children and teens may report double or blurry vision or being bothered by light. NICE's list adds seeing stars, looking through a haze and trouble taking in what the eyes are seeing. Most of these ease as the concussion settles, but double vision right after the injury goes back to the emergency list above.
When symptoms linger, the cause is often how the two eyes team up. In a 2016 study of 100 adolescents aged 11 to 17 seen at a concussion programme, 69% had at least one vision diagnosis.
Focusing problems were found in 51% (accommodative disorders, the eye struggling to switch focus), trouble turning the eyes inwards to read in 49% (convergence insufficiency), and jerky eye movements in 29%. Nearly half had more than one. This was a clinic sample, so it does not give the rate in every child. How two eyes work together explains the teamwork behind the reading problems.
How long does it last, and what about school, reading and screens?
Most children recover within 2 to 4 weeks, according to the CDC, and the AAP says up to 30% have symptoms that last longer. For the first 48 to 72 hours the AAP advises temporarily cutting back physical and mental activity. The child may need a few days off school, and does not have to be completely symptom-free to go back, but should manage 30 to 40 minutes of an activity before a break.
The AAP guidance cited here sets no separate rule for screens or homework. Applied to screens, its 30 to 40 minute guide means treating a screen like any other task: stop when the headache, blur or double vision comes back, rest, and try again later.
The AAP clinical report adds that the aim is to reduce activity, not eliminate it, and to return to full activity in steps while watching for symptoms. Your child's doctor sets the pace for sport. If a headache or blur keeps stopping reading at school, tell the teacher, and the doctor.
When does an eye check help, and what if the eye itself was hit?
An eye check helps when vision symptoms persist, especially trouble with reading, focusing or tracking words at school. The 2016 study concluded a comprehensive visual examination may be helpful for some adolescents with concussion, and that school accommodations should take the vision diagnoses into account. The AAP clinical report says knowing when to refer to a specialist matters for prolonged symptoms.
Start with the doctor looking after the concussion, and ask for an eye referral if reading is the trouble. A paediatric eye check looks at focusing, the eyes' alignment and movement, and the health of the eye. For the double vision itself, when a child says they see double sets out the causes and what to do.
If the eye was hit directly, a separate page applies: a child poked in the eye covers a blunt knock to the eye. A knock to the bone around the eye can also cause a fracture of the eye socket. That page is written for adults, but Dr Catherine Chow explains the mechanism in orbital fractures after a knock to the eye. If a knock to the eye or around it is followed by double vision, go back to the emergency signs above.
- Your child has a seizure, or vomits repeatedly, or has a headache that keeps getting worse.
- Your child is very drowsy, cannot be woken, or lost consciousness, even briefly.
- One pupil is larger than the other, or your child sees double after the injury.
- Clear fluid is running from the nose or ears, or there is a black eye with no direct injury around the eye.
- A baby or toddler will not stop crying, will not feed, or will not settle after a knock to the head.
Common questions
Can my child have a concussion without being knocked out?
Which signs after a head knock mean go to the emergency department?
My child has double vision after hitting their head. Is that an eye problem?
What eye symptoms are common after a concussion?
How long before my child can go back to school and use screens?
When should an eye doctor check a child after a concussion?
What if the knock hit my child's eye directly?
- NICE · Head injury: assessment and early management, NG232 (2023) · www.nice.org.uk
- US Centers for Disease Control and Prevention · HEADS UP: concussion signs and symptoms · www.cdc.gov
- American Academy of Pediatrics · HealthyChildren.org: Concussions in Children and Teens · www.healthychildren.org
- Pediatrics · Sport-Related Concussion in Children and Adolescents (Halstead et al., 2018) · pubmed.ncbi.nlm.nih.gov
- Clinical Pediatrics · Vision Diagnoses Are Common After Concussion in Adolescents (Master et al., 2016) · pubmed.ncbi.nlm.nih.gov