What is myopia and what causes it?
Commonly known as “short-sightedness”, the condition of myopia describes a defect in the eye, where light from a distant object is vision comes into focus before that light reaches the retina, located at the back of the eye. This means that, when the light reaches the retina, the image is out of focus. A too-curved cornea – the surface of the eye – can cause myopia, or myopia can be caused by an overly long distance between the retina and the cornea.
Medical science has long studied what we now understand as “myopia”. Several studies demonstrate that environmental and genetic factors can both play an important role in the myopia development in children. Parents of children with myopia may themselves be myopic, or modern life’s emphasis on increased near-sight work (reading and working on digital devices, for example), coupled with a decreased in the amount of time spent outdoors.
When we look at the human organism in the context of its evolutionary history, we can see that human eye has mostly suffered slight long-sightedness, but mostly normal vision. (This means there is no refractive error caused by the development of the eye. When a clinical study was completed on Inuit populations, the study recorded an enormous difference between younger and older populations. Those in their 40s and above showed a very low incidence of myopia (1.5% incidence), compared to younger Inuit – those under 40 – who showed an incidence of about 50% myopia across the population. This reflected a change in the “life style” of the population in line with economic development, industrialisation, urbanisation and the rise of education in the general population. The development of screens for both education, play and general use has perhaps only accelerated this trend.
This reflects a general trend throughout the world, where myopia has reached almost epidemic proportions.
It is true that close-work has developed in a pivotal part of education in industrialised countries. Not all children in these industrialised countries develop myopia, so there are clearly genetic factors at play. However, it seems clear that modern environmental problems activate the gene in ways that pre-industrial human beings would not have experienced. Excessive near-work seems to be a clear causal factor in myopia (that is, reading and the use of digital devices).
The facts about myopia
Around 90% of teenagers in East Asia have become short-sighted (myopic) in recent times. In Seoul, the number is even higher, at 96% for males who are 19-years old. Myopia has rise in the USA, as well, now affecting 42% of the population. Myopia has become common among Australia school children as well, affecting up to 40% of the population. The ‘myopic progression’ defines the feature of myopia in children: it tends to worsen each year.
Not just glasses
Myopia does not only affect the clarity of someone’s vision. It can also cause eye disease, such as retinal detachment and glaucoma. A short-sighted eye stretches the eye’s delicate structures. This can cause damage and breakage in the eye. This is why it’s important to develop ‘myopia control’: a slow down of the progress of myopia degeneration.
Myopia management versus myopia control
In “myopia management”, the first goal must be clear vision of objects seen from afar. “Myopia control” means, rather, two goals: better farsightedness, but also the slow-down of the myopia development itself.
Various methods of myopia control can be deployed and have been carefully studied over the years, these include but are not limited to, orthokeratology contact lenses, atropine therapy, exposure to sunlight, multifocal glasses:
- Exposure to sunlight means, simply, more time spent outdoors. This reduces, according to several studies completed, the chance of myopia developing, but cannot prevent the progress of the diseases once it has taken root. (Glass walled classrooms, or “outdoor classrooms”, have been proposed as an antidote to this).
- Atropine therapy is the administering of eye drops to the eye, which has been shown to reduce myopia.
- Multifocal glasses and contact lenses have been shown to be successful in the prevention or slowing of progress in children’s myopia. It may be possible to combine methods for the most effective treatment and prevention.
No matter which therapy suits you, you need to make sure you consult with an optometrist experienced in the given methods, which can effectively treat myopia in your child.