Myopia or near sightedness, is one of the most common vision conditions.
Myopia is a common eye condition that is becoming more widespread. Objects up close are in focus while objects in the distance appear blurry.
Myopia is reaching epidemic proportions as young people spend more time focusing on close work on their numerous digital devices. Once myopia starts in childhood, it usually gets worse and worse every year until the age of about 20-25. Unfortunately, the worse myopia gets, the higher the risk of future eye diseases.
Luckily, research has shown that certain treatment strategies can delay or slow down myopia – which should mean less chance of getting an eye disease in the future.
What is myopia?
Myopia, also known as short sightedness and near sightedness, is an eye condition which is reaching epidemic proportions worldwide. It causes blurry distance vision, while objects up close remain clear and in focus.
This most often happens because the eyeball grows longer than normal.
The definition of myopia is having a refractive error (or glasses prescription) of at least -0.50D in one or both eyes.
The opposite of myopia is hyperopia or hypermetropia (also known as long sightedness), which means having a refractive error of +0.50D or more. Hyperopia can cause blurry reading or close vision, and higher levels of hyperopia can also cause blurry distance vision.
Optometrists distinguish between myopia and hyperopia during an eye examination. Believe it or not, sometimes one condition may mimic the other and several specialised tests may be required. Simply reading letters on a chart at a GP’s office or at a school vision screening does not give any information or diagnosis about what someone’s eye condition is.
The definition of high myopia has varied over the years, however it is generally considered to be high when the spectacle prescription reaches -5.00D or greater in one or both eyes. The higher the amount of myopia, the higher the risk of eye diseases such as glaucoma, cataract and retinal detachment.
Myopia generally develops in the childhood or teenage years and this can be influenced by a combination of genetics, environment and other individual visual characteristics.
Some children are more at risk of developing myopia compared to others. Having any of the following risk factors puts a child at an increased risk of developing myopia:
|Age||The earlier myopia begins the quicker the progression|
|Ethnic Background||Myopia is much more common in children of East Asian descent|
|Family History||Having 1 myopic parent = 3x higher risk (2 parents = 6x risk)|
|Refractive Error||Children should normally be long sighted (hyperopia).|
|Time Spent Outdoors||Less than 1.5 hours per day increases myopia risk|
|Time Spent on Near Work||More than 2.5 hours per day increases myopia risk|
There seems to be an increase in the prevalence of myopia globally. East Asians are at greatest risk. It is believed that the increased paced 1st world has created an environment where children do not go outdoors and spend considerably more time staring at computers and digital devices. A study of university students in Singapore revealed the alarming figures of over 90% of this cohort had myopia. It is believed that genetically it should be less than 10%.
Why the massive discrepancy in Singapore?
One theory is that Singapore is a very small area with an oppressively hot climate. It is just a lot more comfortable to stay indoors in air-conditioning, which means that staring at computer screens and smart phones all day is the norm.
Why does myopia get worse every year?
Once myopia starts, it generally gets worse as time goes on. If it gets worse at a fast rate, there is more chance of ending up with high myopia. It is also important to note that in most cases most people with myopia slow down dramatically after the age of 25. It is thought that the myopia progression slows down after 25 because humans have grown to a maximum and the eye structures (in particular the sclera becomes more sclerotic, which in turn means that the eyes cannot stretch any further. The longer the eye becomes, the more myopic it will become.
Effects of myopia
Unfortunately, myopia (even a very low amount) increases the risk of many eye diseases. The higher the myopia, the higher the risk.
Here are some examples of the increased risk, compared to someone that does not have myopia:
|Amount of Myopia||Retinal Detachment Risk||Glaucoma Risk||Cataract Risk||Macula Disease|
|-1.00 to -3.00||3.1x higher risk||4x higher risk||2.1x higher risk||2.2x higher risk|
|-3.00 to -6.00||9x higher risk||4x higher risk||3.1x higher risk||10-40x higher risk|
|-6.00 to -9.00||21.5x higher risk||4x higher risk||5.5x higher risk||127x higher risk|
|-9.00 or greater||44.2x higher risk||4x higher risk||5.5x higher risk||349x higher risk|
The good news is, there are simple strategies that can delay the onset of myopia and also slow it down once it starts.
Delaying or preventing myopia can reduce the risk of getting high myopia, and thus reduce the risk of future eye diseases.
A pair of glasses can make the distance vision clear, but glasses alone do not stop the myopia from getting worse. Myopia control treatments aim to slow down or stop myopia from getting worse. Atropine eye drops, orthokeratology and multifocal contact lenses are all options to slow progress of this condition. Based on the latest research, the following treatments can slow down myopia:
|Treatment||Effect on slowing down myopia|
|Orthokeratology (ortho-k) lenses||30 – 56%|
|Multifocal soft contact lenses||25 – 72%|
|Atropine eye drops||34 – 96%|
|Executive Bifocal glasses||39 – 51%|
|Progressive glasses||11 – 33%|
Depending on each child’s individual characteristics, optometrists at The Eye Practice can customise a treatment plan to help achieve the maximum myopia control effect possible. It is not uncommon for us to combine treatments, especially in high risk cases, where the child is young and one or both the parents are myopic.
PLEASE READ: The information given under Eye Conditions is of a general nature and is not intended to be advice on any particular matter. Please take the appropriate Optometrical advice before acting on any information given under Eye Conditions of The Eye Practice web-site.