In his own words, Dr Sun Chen-Hsin, Consultant Opthalmologist from the National University Hospital explains why it is crucial to get ahead of your child’s myopia with timely, evidence-based treatments to prevent sight-threatening conditions in later life
Refractive error is the leading cause of blurry vision in school-going children in Singapore. Blurry vision is typically caused by myopia (short-sightedness), hyperopia (long-sightedness) or astigmatism (blurred distance and near vision), with myopia being the most common eye condition affecting children in Singapore today.
According to the Strabismus, Amblyopia, and Refractive Error in Young Singaporean Children (STARS) study, blurry vision caused by myopia is seen in 11% of children aged 6 to 72 months. Statistics from the Singapore National Eye Centre further reveal that 10% of Singaporean children develop myopia by age 5, increasing to 60% and 80% by ages 12 and 18 respectively.
When blurry vision develops at a young age, pre-verbal children who have not developed their language skills can find it challenging to communicate their vision problems to parents. Most children may not even understand what blurry vision is and assume it is normal, delaying diagnosis and treatment.
If intervention is not introduced early, myopia can progress to high myopia. The Singapore Ministry of Health predicts that by 2050, up to 90% of Singaporean adults over 18 will be myopic, with 15% to 25% at risk of high myopia, which puts them at risk of sight-threatening conditions in later life . High myopia, defined as near-sightedness of more than -6.00 diopters or an eyeball length longer 26mm, increases one’s risk of sight-threatening vision disorders. These include early cataracts, glaucoma, retinal detachment which causes blindness, and macular degeneration where there is no cure.
How to detect blurry vision in children
Because children are often unable to articulate problems with their vision, parents, teachers, and caregivers must be proactive in looking out for signs and symptoms of myopia in young children. For example, pre-verbal children between the ages of 3 and 4 often squint when trying to see distant objects or move closer to objects they want to focus on. Tilting the head to see an object may indicate astigmatism.
For school-going kids aged 5 and above, teachers play a crucial role in noticing if a child has difficulty seeing. Signs such as needing to sit closer to the whiteboard, frequent complaints of headaches, reduced participation in class when seated at the back of the room, and increased participation when seated at the front, could indicate the child is suffering from vision problems.
Fortunately, in Singapore, there are Childhood Developmental Screenings for citizens and permanent residents to assess blurry vision in children. Young children aged one to four are assessed by general practitioners (GPs) in polyclinics to determine if they exhibit symptoms of vision problems such as poor eye contact or uncoordinated eye movements. When children turn 4, they undergo a visual acuity test with the Snellen chart, which is conducted annually under the Health Promotion Board (HPB)’s Youth Preventive Health Services in primary schools.
In general, children with a visual acuity of 6/12 or worse will be directed to eye care professionals (ECPs), with children ages seven and below referred to ophthalmologists, while older children are referred to optometrists.
Treatment options for myopia and myopia progression
Children can experience different types of refractive errors simultaneously, not just myopia, which is why it is crucial to determine the true cause or causes of vision problems.
Blurry vision due to myopia, hyperopia and astigmatism can be made clear by regular “single vision” optical lenses, and they are the go-to treatment for most children with myopia. Although these lenses fixes the problem of blurry vision and enable children to see clearly, they do not prevent further progression of myopia due to progressive elongation of the eyeball. This means the lenses must be updated periodically as the child’s myopia degree increases.
To control myopia progression, we must control its root cause, which is the elongation of the eyeball. Myopia progression can be managed using lifestyle modifications, pharmacological treatments or optical interventions, or a combination of all three.
Generally, I find that lifestyle modifications when coupled with evidence-based treatments, yield the best results. I recommend spending more time outdoors and reducing near work as these have been shown to prevent nearsightedness in children.
In one Australian study, students who spent more time doing near work and less time outdoors had a higher risk of myopia than children who spent less time on near work and more time outdoors . Other studies showed that although Australian children read more books, a form of near work, per week than their Singaporean counterparts, the prevalence of myopia in Singaporean children (29.1%) was significantly higher compared to Australian children (3.3%) as Australian children spend at least three hours outdoors per week, compared to Singaporean children who only spend about 13.75 minutes outdoors per week.
Pharmacological treatments such as atropine eye drops have been shown to control myopia progression effectively even in patients on the lowest dose (0.01%) .
Optical interventions include myopia management contact lenses and spectacles. These novel lenses differ from traditional lenses as they create rings of ‘peripheral defocus’ that bring the focus of light rays forward to match the natural curvature of eyeballs.
Scientists have hypothesized that bringing focus in the peripheral retina to the front of the retina can prevent myopia progression. This has been proven in research including studies of myopia management glasses in Hong Kong which showed that children who wore single-vision lenses experienced an increase in myopia of 100 degrees, while those using myopia control lenses only regressed by 40 degrees over a two-year period. In other research involving a multicentre study of dual-focus contact lenses performed in the United Kingdom, Portugal, Canada and Singapore, these lenses have been shown to slow down myopia progression by up to 50% in children aged eight to 17 years.
While early intervention is ideal when managing myopia, studies show introducing dual-focus contact lenses at any age have been effective in slowing down or controlling myopia progression. Compared to overnight Orthokeratology lenses, daily disposable contact lenses also reduce the risk of eye infection in younger children, who may not be able to care for their lenses without adult assistance.
These special myopia control contact lenses should be considered for children who are very active or those whose myopia continues to progress despite using other interventions. Contact lenses are also ideal for patients who are anisometropic, or have myopia in only one eye, as it eliminates the risk of double vision that can arise with wearing glasses.
Fortunately, while Singapore’s competitive academic environment continues to play a significant role in the rising levels of myopia in our children, eye care practitioners are now equipped to detect and diagnose myopia in children as young as two years old, and a range of evidence-based treatments to control myopia. Hopefully with sufficient awareness and proactive action, the myopia epidemic can be curtailed before it becomes critical.
First published by Medical Channel Asia