A common condition in Hong Kong, Vanessa Thai introduces the signs and symptoms of myopia and explains how it can be treated.
What is myopia?
Myopia, also known as short/near-sightedness is the term that describes when you are able to see objects clearly up close (laptop or a book) but not at a distance (TV/movie screen or have difficulty recognising people in the distance).
Myopia occurs in eyes that focus images in front of, rather than directly on, the retina causing blurred vision. This is caused by, either acting alone or in combination, the cornea or lens being misshapen or the eyeball being too long.
Signs and symptoms
Undiagnosed myopia can lead to headaches and eyestrain as distance vision is blurred.
A myopic child may:
Squint to see distant objects
Have trouble seeing the board in the classroom
Have poor reading posture
Show little interest in outdoor games
Onset and prevalence
Genetics and the environment play a role in the development and progression of myopia. Environmental factors include prolonged near focusing tasks, eyelid pressure, poor lighting and reduced outdoor time. Children who suffer from myopia at a young age are at an increased risk of high myopia later in life. High myopia contributes to higher risks of retinal complications, cataract and glaucoma, which may result in blindness.
The prevalence of myopia is increasing at an alarming rate – with studies suggesting that up to 80 per cent of the population in some East Asian countries may be myopic, mainly due to intensive education and less time spent outdoors. It is estimated that 2.6 billion people or 30 per cent of the world’s population will be myopic by year 2020.
Traditional treatment options such as single vision distance glasses and contact lenses correct the distance blur, but do not slow the progression of myopia caused by the lengthening of the eyeball.
Conventional glasses prescribed for seeing clearly in the distance are the simplest treatment option, however, they do not treat any focusing and eye-teaming problems that may also be present. These problems may be contributing to the progression of myopia. Your optometrist may need to prescribe glasses with enhanced near vision or multifocal (progressive) lenses to simultaneously correct the distance blur and help reduce the impact eyestrain at near. Vision therapy may also need to be recommended.
Orthokeratology (also known as ortho-K or OK) involves using a hard contact lens overnight to flatten the cornea. Good vision can be achieved without glasses or contact lenses during the day. However, overnight lens wear increases the risk of eye infections. Studies have shown that ortho-K lens wear can also slow the lengthening of the eyeball and myopia progression. Children as young as six years of age can be successfully fitted with ortho-K lenses. However, it is more commonly prescribed in pre-teens and teenagers.
Topical atropine eye drops
A recent extensive five-year study by ATOM (Atropine for the Treatment of Myopia) showed significant results in myopia control using atropine eye drops. Atropine is used for relaxing the focusing muscles of the eye and dilating (widening) pupils. Higher concentrations of atropine can result in blurred near vision, excessive pupil dilation and significant light sensitivity. However, low dose atropine drops can yield excellent results with minimal side effects.
More outdoor activity may provide a simple solution for myopia control as well protection against the onset of myopia. The risk of myopia is reduced when children spend sufficient time outdoors (more than two hours per day). In Australia, it was found that non-myopic six-year-old children spent four to five hours more per week outdoors compared with myopic children. Asian children living in Sydney spend 11 hours more per week outdoors compared to Asian children in Singapore resulting in three per cent versus 30 per cent prevalence of myopia, respectively.
Which treatment is most suitable for your child?
Multifocal glasses, orthokeratology, atropine and/or time spent outdoors can all slow the progression of myopia. Your optometrist can help advise on the most suitable treatment, or a combination of treatments, for your child depending on their condition.