Our expert paediatric orthoptist Rudrika Joshi-Borrel tells us all about vision development in babies:
Did you know that almost all babies are long sighted when they are born? In most cases the eyes will correct themselves within 2 years, in a process called emmetropization.
As an orthoptist, I am a specialist in helping people with squints and similar eye conditions. If I am examining a 2 year old child, glasses are not always necessary due to the commonality of long-sightedness. On the contrary, short-sightedness in children of this age is much more unusual. Read more about long and short sightedness in our blog: "What are myopia, hypermetropia and astigmatism?”
Emmetropization is when the eye’s process of aligning its axial length to the focal length of its optics; however, imperfect alignment causes short-sightedness, and both genetics and environment can have an impact upon this process. For example, there is strong evidence to suggest that children who less time outside are more at risk. (refer below for the studies). When emmetropization doesn’t happen, light entering the eye isn’t properly focused on the retina and so the brain receives a blurred image. A secondary effect of this is that neural pathways in the brain responsible for sight start to get ‘lazy’, thus working less effectively.
An eye test, called a refraction test, needs to be done in this case as this measures which prescription lenses the child will need in order to correct their sight. If the child is given the right prescription, their vision be immediately corrected whilst wearing the glasses, and refractive adaptation will begin. So wearing glasses can actually exercise the visual system in such a way that the eye and brain eventually adapt to self-correct the child’s sight.
The more often a child wears their glasses the more adaptation occurs.There is a bit of neuroscience behind this; because the brain now receives a clear image from the optical nerves the visual pathways in the brain are stimulated to work properly. This reawakens the neural pathways.
Refractive adaptation does not always completely restore perfect vision, but does much to significantly improve it. Depending on the length of time the child’s vision has been left untouched, treatments such as occlusion may well be needed in order to further stimulate the cells, so the earlier the better. Research shows that a full 18 weeks with glasses is the maximum potential time period for refractive adaptation to have an impact, before occlusion is necessary.
Glasses make up for the miscalculation between the lens and the size of the eye; however, this will only slightly change as a child grows, as long as the prescription is very small. In these cases, the optician may advise them to wear their glasses as teenagers when at school, work, the cinema and whilst driving. For children under the age of 10, however, it is advisable to wear glasses full time.
The coordination of eye movement develops after birth once a baby sees for the first time. Whilst this development progresses it can be normal for babies to look slightly cross eyed up until about 6 months of age.
Naturally if you’re a parent you might be concerned by this, especially if it continues beyond 6 months. If you’re a bit worried, seek medical advice at the GP. If a problem is spotted then the GP may refer your child to a paediatric ophthalmic (children’s eye specialist), like My iClinic. From there a proper diagnosis and treatment plan can be made by a doctor if necessary.
If you are wondering who do you need to see, here is a list of specialists and what they do in the eye world:
Opticians and Optometrist specialise in glasses and eye tests, prescribing glasses and may detect eye diseases.
Orthoptists specialise in the non-surgical diagnosis, such as the management of squints, amblyopia and eye movement disorders, isolated and secondary to systemic disease.?
Ophthalmologists are the medically trained doctors and surgeons specialised in the diagnosis and treatment of eye diseases and disorders. They can also perform “refraction tests” and prescribe glasses.