The strength or power of your optical prescription is measured in dioptres (di-opt-ers) and relates to the angle of light you need to bend into your eye to correct your vision. If you have a negative prescription, you’re short-sighted or have what’s called myopia. It’s also called nearsightedness just to confuse things even further (because you can only see near or close up, and not far away).
So how common or ‘average’ is your eye prescription? This is an area of data that has some gaps, and is not measured by the UK government or NHS. Shocking, right?
There is some information out there though that can help us answer this.
The WHO published that the estimated number of people with myopia will increase from 1.95 billion in 2010 to 3.36 billion in 2030. For high myopia (over -5 diopters), from 277.2 million in 2010 to 516.7 million in 2030 .
They also previously estimated that levels of high myopia would be 10% of the global population by 2050 .
We talk about why these figures are going up in our article about the myopia crisis.
So how is the data spread currently across prescriptions? The graph below from Bio Bank shows a large 2018 UK study with 114,686 participants . Currently about 4% of the UK population is above - 5. The maximum in this study was + 13.9625 and the minimum was - 24.17.
We’re raising awareness of the increasing rates of myopia, and hope in the future to be able to monitor this more accurately in order to plan out our eye healthcare needs. Plus we're creating glasses frames optimised for thicker lenses - take a look.
 2019, The World Health Organisation, World report on vision (who.int)
 2015, The World Health Organisation, The Impact of Myopia and High Myopia
 2018 - Bio Bank - Visual Acuity: assessment