What Is Myopia
Myopia is blurry long-distance vision, often called "short-sighted" or "near-sighted". A person with myopia can see clearly up close – when reading a book or looking at a phone – but words and objects look fuzzy on a blackboard, on television or when driving. But a pair of glasses aren't the whole story.
The prevalence among Australian 12 year olds has doubled in 6 years. Myopia in kids tends to progress or get worse throughout childhood, and higher levels of myopia are associated with higher eye disease risks in adulthood. If your child already wears glasses, you can do something to stop their vision worsening. If they don't you can assess their risk of developing myopia.
What causes myopia
If a person’s eyeball is elongated or their cornea is too curved, it affects where light is focussed inside the eye. Instead of hitting the retina at the back of the eye, light falls short of the surface, causing objects in the distance to appear blurry. It’s just like setting up a projector; the image won’t be clear if the screen is positioned too far away from the projector.
Myopia in young children
Myopia progresses quickly in younger children, as their eyes are growing at a faster rate. Younger children with myopia may therefore require a stronger prescription more frequently, and could be at a higher risk of developing additional eye problems in the future. It can be hard to diagnose myopia in babies and toddlers as they often don’t realise or can’t express the problem.
Childhood onset myopia
Childhood onset myopia is most commonly caused when the eyeball grows too quickly, or continues to grow after age 10–12 when eye growth should normally cease. In recent years, short-sightedness in children has been increasing. Rates of myopia among Australian 12 year olds have doubled in 6 years, in part due to the increased use of handheld electronics and less time spent outdoors.
Adult onset myopia
Adult onset myopia is usually caused when the muscles used for focussing the eyes up close become strained or fatigued. This may be due to a significant increase in close work, such as undertaking university studies or working with screens, or could be a result of improperly corrected vision, such as not wearing glasses when needed, or using the wrong prescription.
Why should I be concerned about myopia
Because children’s bodies are still growing, myopia tends to progress or get worse throughout childhood. The condition develops more quickly in younger children than in older children, as their eyes are growing at a faster rate.
The average age for developing myopia is reducing. Younger onset of myopia means faster eye growth over a longer period of time, which causes two main issues for children with myopia: progressively worsening vision throughout childhood, and an increased risk of eye diseases in adulthood.
The following eye diseases can be linked to myopia. These can onset even in early adulthood when myopia is high, and the risk increases with older age:
The retina is the light-sensitive tissue that lines the back of the inside of the eyeball. Retinal detachment is when the retina is pulled away from its normal position. Depending on the severity of the detachment, and how quickly it is treated, it can cause anything from distorted vision to permanent blindness.
Myopic macular degeneration
The macula is the central part of the retina and is responsible for creating a sharp, focussed image. If a person is very short-sighted due to elongation of the eyeball, the macula can stretch and tear over time. This causes a loss of central vision clarity, like having a thick smudge permanently in the middle of your vision.
Glaucoma is a condition where a buildup of fluid in the eye increases pressure on the optic nerve, causing damage. It usually affects both eyes and starts with a deterioration in peripheral vision, which often goes unnoticed for a long period of time. If left untreated, advanced glaucoma can lead to blindness.
Cataracts are caused when proteins and fibres in the eye’s focussing lens start to break down, becoming thicker and less transparent over time. This results in a cloudy patch in the middle of the eye, like a foggy windscreen. Cataracts commonly develop in old age but can be present from birth or develop during childhood. With myopia, cataracts can develop in middle age or earlier.
Why does myopia develop
Myopia can develop during childhood, adolescence or adulthood, and can be caused by a variety of different factors, some of which are out of our control.
Too much close work
Spending more time on close work has been linked to development of myopia. This includes reading, drawing, playing computer games, and using smartphones or tablets. The rise in the popularity of handheld devices means that children are now exposed to close work from younger and younger ages, putting them at a higher risk of myopia development.
While it is often linked to environmental factors, myopia can also be hereditary. A person with one short-sighted parent has 3 times the risk of developing myopia, or 6 times the risk if both parents are short-sighted. Research also suggests a link between Asian ethnicity and faster progression of myopia, with a higher worldwide rate in this group.
Under- or over-corrected vision
Under- or over-corrected vision has been shown to promote the onset and accelerate the progression of myopia. Not wearing the correct glasses prescription, or not wearing glasses when they are needed, can cause eye strain that distorts the shape of the eye, leading to short-sightedness.
Not enough time outdoors
Research has found that spending time playing outside as a child may reduce the chances of becoming short-sighted, and may slow the progression of existing myopia. This may be related to light levels outdoors being much brighter than indoors. Both sport and relaxation outdoors appear to be beneficial in reducing the risk of short-sightedness.
How can I slow myopia progression
Understanding the causes and symptoms can help to reduce the risk of myopia in your child, or slow down its progression.
Step 1Look out for early signs
The earlier you catch signs of myopia, the more can be done to treat it and slow down progression. Familiarise yourself with the symptoms of myopia and pay close attention to how your child interacts with their environment.
Step 2Book regular eye tests
Younger children may not realise or be able to communicate that there is a problem with their vision, so regular eye tests are extremely important. An eye care professional will be able to examine your child’s eyes to assess their vision and eye health.
Step 3Take breaks from close work
Reading, learning from screens and doing homework are important for children and teens, but they should take short breaks from close work every 20 minutes to relax the focussing muscles of the eyes. Keeping at least a forearm’s distance between their eyes and their close work at all times helps to reduce eye strain and risk of myopia.
Step 4Limit screen time
Younger and younger children are using smartphones and tablets on a regular basis. However, too much screen time is linked to myopia, eye strain and dry eye symptoms. School-aged children and teens should ideally not spend more than two hours per day outside of school on screen time.
Step 5Encourage time outdoors
There is evidence to suggest that exposure to outdoor light is beneficial in slowing the onset and progression of myopia. Children should be encouraged to spend 90 minutes outdoors every day, whether that’s walking, relaxing or playing sport, but should make sure to wear a hat and sunglasses and seek shade to prevent UV damage.
Step 6Ask about myopia treatments
Standard spectacles and contact lenses correct blurred vision but don’t slow down the worsening of myopia. Special types of spectacles and contact lenses for children and teens can do both, while atropine eye drops have been shown to help slow myopia. Ask your eye care professional about which of these may best suit your child.
Further reading if your child is already myopic
As well as the steps outlined above, there are a number of options available to slow the progression of myopia and minimise worsening vision and the risk of more serious eye health concerns.
Special types of spectacles and contact lenses currently offer the best vision correction options to slow the progression of myopia, although some work more effectively than others. Standard types of spectacles and contact lenses don’t offer the benefit of slowing myopia progression, and will only correct your child’s blurred vision.
Atropine eye drops have also been shown to slow the progression of myopia. Different concentrations have different effectiveness, so it might take time to find the right option for your child. It’s important to note that these eye drops don’t correct vision, so your child will still need spectacles or contact lenses.
For more advice on slowing the progression of myopia, head to our knowledge centre. Our clinical website for eye care professionals, Myopia Profile, also provides more detail.