HealthAgenda

Short-sightedness is on the rise. We investigate ways to manage and even prevent it in both children and adults.

Nicola Conville
January 2019

Myopia, also called short-sightedness, is a common condition in which close objects appear clear, but faraway objects appear blurry. It’s the most common eye problem affecting children and is rapidly growing around the world, reports the Brien Holden Vision Institute. There are currently 4 million cases of myopia in Australia, which is tipped to jump to 22 million by 2050.

But why is it on the rise? Some experts say spending time indoors, away from natural light, could be partly to blame.

Understanding the condition

Myopia usually begins in childhood (from age 6 onwards) and can worsen through to early adult years. It can also occur in adults with no prior history of eye problems and affect babies at birth (known as congenital myopia).

A myopic eye is too long from front to back, says the US National Eye Institute. As a result, light rays focus in front on the retina instead of on it, bringing clarity to close vision but blurriness far away. The retina is at the back of the eye.

Professor Padmaja Sankaridurg, head of the Global Myopia Centre at the Brien Holden Vision Institute, says that uncorrected short-sightedness in children can impact classroom involvement, social development and peer engagement. If uncorrected into adulthood, there can be further complications.

“High myopia increases the risk of vision impairment and also sight-threatening complications such as myopic maculopathy, cataracts, glaucoma” and retinal detachment.

Although the condition can’t be cured, corrective glasses or contact lenses to adjust the focus onto the retina can improve vision and reduce future deterioration. Prof Sankaridurg recommends regular testing and monitoring to ensure you stay on top of treatment.

What causes myopia?

Short-sightedness is influenced by both genetic and environmental factors but an exact cause isn’t known. Optometrist Dr Jessica Chester explains that if both of your parents have myopia, you’ll probably develop it too.

Environmental factors, she adds, can include staring at close objects such as books and screens for too long without regular breaks.

The Royal Australian and New Zealand College of Ophthalmologists explains that although there’s no hard evidence that screen time adversely affects children’s eyesight, we should keep it to a minimum. Read the Australian Government guidelines on screen time.

The benefits of light

What is emerging though is growing evidence of the role of outdoor time (safe exposure to natural daylight) on healthy eye development.

Researchers from the University of Sydney say exposure to sunlight at a young age assists in the growth of a healthy eyeball, preventing it from growing too fast or becoming too long (front to back) or oval-shaped instead of round. Their Sydney Adolescent and Eye Study found that children who spent more time outdoors were less likely to have myopia, even if children were also doing a lot of reading and studying.

Prof Sankaridurg explains the benefits could be related to higher levels of light exposure outdoors compared to indoor environments; the composition of light; the fact that the pupil is smaller when outdoors; or the extended depth of field.

She recommends adults and children spend a minimum of 2 hours outside daily, with more time considered beneficial. Putting on a pair of sunglasses to stay sun safe won’t detract from the benefits, she adds, as daytime light levels are high.

While too much exposure to the sun’s UV light is harmful, safe exposure to natural light is key. For young children it could be gained, for example, through a morning play at the park, walking to and from school, after-school sports, and being outdoors at recess and lunchtime.

Clocking up healthy daylight time for adults could include enjoying lunch outdoors in the shade, walking to and from the train station or an early evening walk.

When to get an eye test

Visit an optometrist for an eye exam if you or your child shows signs of sight problems. In kids it can be hard for them to notice blurriness because it feels normal to them, but you might find they:

• screw up their eyes to see distant objects
• have difficulty reading the whiteboard at school
• show poor posture when reading, such as hunching over a book or pulling it close to their face
• show a lack of interest in playing outdoor games, as they may not see well enough to confidently participate.

For adults, you might have difficultly seeing objects in the distance, such as road signs, scoreboards and faces.

Regular eye check-ups will help diagnose problems early and correct your vision. Dr Chester advises children have yearly eye tests and adults every 1-2 years. The Royal Australian and New Zealand College of Ophthalmologists encourages parents to get their child’s sight tested before the age of 5.