As a paediatric optometrist, time and time again I see parents mortified at the thought that their child has been going about their daily activities coping with an underlying vision problem that they didn’t have a clue about. Kids were born with one pair of eyes, so however they are working, their perception is often that the way they see the world must be “normal”. As children have such strong eye muscles they are truly remarkable at compensating for and tolerating higher prescriptions, masking the underlying issues.
Also concepts such as whether something looks ‘blurry’ or ‘clear’ are not easy for younger children to comprehend – that is why a variety of methods and testing resources are necessary for us to be able to test even the tiniest of eyes. If you have any concerns at all – the sooner the eye test the better, we have checked bubs as young as 10 months old.
I have decided to focus on one of the conditions at the top of my list of why parents should have their children’s vision checked – the lazy eye without the presence of an obvious eye turn. This is the least parent-friendly to detect, as a child can appear to have completely normal vision as their better eye takes over doing all the work. A ‘lazy eye’ (amblyopia) is a rather generalized term to describe the fact that one eye has poorer sight (in some cases even legal blindness) relative to the other eye.
There are two primary reasons why this occurs: the first is a very large asymmetry in prescription between the two eyes (refractive amblyopia), and the second is an eye turn (strabismic amblyopia) which shifts the focal point of the eye off-centre. In some rare cases ocular health problems such as a congenital cataract (being born with a cloudy lens) or retinoblastoma (infantile tumour at the back of the eye) can also cause amblyopia.
Refractive amblyopia occurs because a child’s better eye ends up carrying the bulk of the visual workload, overtaking the amblyopic eye. As the brain does not favour the poorer eye or in some cases suppresses it altogether – the neurological connections wiring our eye to our brain that develop only whilst we are children (before 10 years of age) do not form and the child is left with permanently impaired vision in one eye.
The treatment in these instances is often glasses (or contact lenses) to correct each eye with the required prescription this typically means that one glasses lens will appear thicker than the other as the poorer eye needs a stronger prescription to assist it to focus. If there is a significant difference in vision level between a child’s eyes, the better eye may also need to wear an eye patch for 2-3hours/day at home to encourage the brain to use the amblyopic eye.
Strabismic amblyopia is much easier for parents or other health practitioners (eg. paediatrician) to pick up. Straightening the eye turn is achievable with glasses correction in the majority of instances however, in more severe cases surgical realignment of the extraocular muscles may need to be performed by an ophthalmologist.
I cannot stress how important it is to have a child’s vision checked, because we only have such a short time frame to correct any issues! Research indicates that the wiring of nerve fibres connecting the eye to the brain, finishes between the ages of 8-10 years old in most children. This means that we need to implement treatment options as early as possible to have fully corrected the problem before a child reaches this age range.
I will conclude with a list of some subtle signs that you can monitor your little one for that may suggest an underlying condition, but even in the absence of any concerns – an eye exam prior to starting prep in my opinion is mandatory.
- Short attention span for near activities
- Squinting or excessive blinking when watching the TV
- Sitting close to the TV
- Repetitive eye rubbing
- Headaches or tired eyes
- Holding the book too close when reading
- Poorer than normal fine/gross motor skills
- Slow to meet developmental milestones (eg. walking, tying shoelaces)
- An eye turn when tired
- Any reporting of double vision
- Letter mix-ups and/or skipping rows when reading
- Abnormal colour discrimination
Kylie McNeill – Paediatric Optometrist
“Hey Kylie – I am qualified to test your eyes, honestly!”