Myopia (Short-Sightedness)

Myopia (Short-Sightedness)

What is myopia?

Myopia (aka short-sightedness or near-sightedness) is a condition of the eye in which objects in the distance (i.e. board at school, TV) appear blurring, but near vision (book, iPad/iPhone) is clear.

The usual reason for this is that the eyeball has grown too long. As a child grows, the eye grows also. For some children, due to factors listed below, their eyes grow longer than normal, especially during rapid changes that occur during puberty. This is why myopia generally develops in childhood or in teens.

What factors increase the risk of myopia? Nature (genetics) versus nurture (environment)

Genetics: for a long time it has been known that there is a genetic component to myopia. Having one parent who is myopic doubles the risk of myopia, and having two parents increases the risk by 8 times.

Environment:

- Time spent indoors vs outdoors – more time outdoors seems to result in less myopia. Recommended is 2 hours a day (14 hours a week) outdoors.

- Time spent on close-up work – more time on reading and on screens is associated with more myopia.

What causes myopia?

Children who have a genetic and/or environmental predisposition, and who also have a visual system which finds seeing up-close stressful (known as near-point-stress), have a high chance of developing myopia.

Previously, the standard approach to managing myopia development was simply to wait until a child became myopic and then to prescribe glasses to correct the distance focus error. As the child’s eyes inevitably worsened, stronger glasses were prescribed. This was continued until the child’s vision stopped getting worse, often in their late teens or early 20s. The result was often a significant visual disability, only correctable with strong glasses or contact lenses.

With a new and greater understanding of what causes myopia, optometrists are now able to determine whether a child has a risk of becoming myopic, and intervene before a child notices any vision problems. This proactive approach to myopia is known as preventive medicine; it reduces the progression of myopia thereby reducing the eye health risks associated with higher levels of myopia.

If a child does become myopic, treatments are now focussed on addressing not just the distance blur, but also the up-close factors that cause progression, with the aim to slow down or stop myopia getting worse. This often involves addressing the near point stress with bifocal glasses or bifocal contact lenses. 

What about the future?

If your child is myopic, the likelihood is that it will continue progress as they grow. For some children, this is a slow rate of progression, while others have rapid vision changes.

Treatment is tailored to your child’s vision and eyes to attempt to reduce the progression as much as possible.

The risk of myopia progressing becomes less during the later teen years and young adult years, however, whilst the environmental risk factors are still present, the risk remains, albeit low.

Hence, for continued effect, treatment needs to continue for as long as there is a risk of myopia increase, which may be through the tertiary study years.

Why is it important to be proactive?

Those with myopia don’t just suffer the hassle of wearing glasses or contact lenses. The longer eyeball length of a myopic eye is associated with an increased risk of retinal detachment, glaucoma, cataract and myopic macular degeneration later in life. These are potential sight-threatening conditions; the worse the myopia the higher the risk. Thus it is important to aim to either prevent or reduce myopia to keep these risks as low as possible.

What treatment is best?

A tailored approach to your child’s needs is critical. Your OCULA optometrist will discuss with you your child’s myopia profile, highlighting the relevant risk factors, and will talk through the treatment options available for your child.

Treatment options

Chance of slowing down or stopping myopia progression

Standard single vision distance glasses or contact lenses

0-5%

Progressive or bifocal glasses

12-55%

Zeiss Myovision glasses

0-30%

Soft, disposable progressive contact lenses

29-45%

Atropine eye drops

30-77%

Progressive or bifocal glasses + atropine

50-77%

OrthoK (orthokeratology)

12-100%

OrthoK + atropine eye drops

30-100%

 

At this time, orthokeratology is considered the most effective form of myopia control. Further information on the specific treatment options is available on these links: orthokeratology, soft contact lenses, atropine and specially-designed spectacle lens. 

Environmental risk factors are unlikely to affect the management pathway, however, they are modifiable and should be considered in view of the overall myopia risk profile. Tips for modifying environmental risk:

Good visual habits

- Spend time outside. Walk the dog, ride a bike, play in the backyard, sit outside in shade. It is the brightness of natural sunlight, which is beneficial rather than UV light–still take sun protection precautions. 

- Take regular breaks from close work. Look away for a minute or so to change your focus, or change your task every 30-60 minutes to alter the demand on your visual efficiency (eye teaming) systems.

- Try to limit near tasks (after school/ work) to 2 hours per day. This also includes leisure time – ensure it is not primarily spent on handheld digital devices or other close vision tasks like reading and drawing. On the weekends, ensure a balance between inside and outside time, and increase natural lighting.