Myopia (short-sightedness)
The terms short, or near sightedness, are used when the condition myopia exists, which is the ability to have clear vision close-up but not in the distance.
Around 20 -25 percent of Australians are myopic.
People with low amounts of myopia may only need to wear glasses when driving at night and at the movies, while higher amounts of myopia may require glasses to be worn even when reading.
Myopia occurs when light focuses short of the retina at the back of the eye. This is usually because the eye is too long.
People with moderate or low amounts of myopia will find themselves removing their glasses to read once they acquire presbyopia in their mid forties.
Myopia is corrected by wearing glasses fitted with concave or minus lenses, contact lenses or by undertaking refractive surgery.
The most common type of myopia (physiological myopia) develops in childhood and generally continues to increase until the eye is fully grown. The number people in the population with this type of myopia have dramatically increased around the world over the last 50 years and as a result, several new theories on why eyes become myopic are now being debated.
For myopic children, generally multifocal spectacles are fitted to best allow distance and near visual accuracy in the classroom ie so that the distance prescription does not excessively strain the child’s eyes when reading.
In the early stages of myopia or for low to moderate myopia it is possible to undergo Orthokeratology contact lens fitting, which involves wearing contact lenses at night to allow vision unaided during the day.
Some research suggests that Orthokeratology may reduce progression of myopia. This has also been thought to be true, to a lesser extent, with daytime Rigid gas permeable contact lenses.
Other forms of hard and soft contact lenses can be fitted to allow clear vision during the day.