This medical term describes when a person cannot see distance objects clearly without the need for a corrective minus lens. The traditional view is that light entering the eye from the distance is focussed too early and so the image is blurred. It is also known as near-sightedness or short-sightedness.
People with myopia are often those who enjoy reading or using a computer a lot, but this doesn’t necessarily mean that their near vision is better than those who do not have myopia.
How common is myopia and when does it start?
In Australia, it is estimated that 20% of adults have myopia and it is generally accepted that the first symptoms of myopia are experienced around puberty. In Asian cultures where children start learning characters at 3 years old, the prevalence of myopia can be as high as 80% of the population.
Recent research has suggested careful screening of children at age eight may help identify those children who are at risk of developing myopia. The scientific community also now agrees that myopia is associated with environmental factors that are responsible for its progression.
Current research is investigating the interaction of prolonged focussing effort with close tasks, eye lid pressures and poor lighting as aetiological factors in the development of myopia. However the exact mechanism is still not known.
What can be done?
Currently there is no cure for myopia. However, recognising that prolonged near tasks may be a contributing factor for the genesis of myopia, your behavioural optometrist will advise you on proper posture, working distance, lighting and other techniques to help reduce the impact of near visual stress.
A lens to make distance viewing clear is the simplest treatment, but is not necessarily the best correction for myopia. It compensates for the distance blur but does not treat any focussing and eye-teaming problems that may also be present and which may be contributing to the myopic progression. Your behavioural optometrist may need to prescribe special spectacle lenses such as enhanced near vision lenses, bifocals or multifocals as a way of clearing the distance blur and at the same time assisting in treating the focusing or eye-teaming problems. Vision therapy may also need to be applied.
Other corrective options available are contact lenses, surgery and accelerated orthokeratology. Clinical trials have indicated that wearers of rigid gas permeable lenses and orthokeratology lenses may show a decreased rate of myopia progression but these results are yet to be fully proven by research.
Orthokeratology involves using a specially designed contact lens to reshape your cornea while you sleep. Upon waking you remove the lens and enjoy good daytime vision without the need for spectacles or contact lenses. Orthokeratology is reversible and so does not permanently cure your myopia.