In the UK, the proportion of teenagers with myopia has doubled over the past 50 years (McCullough et al, 2016). Globally, almost one-third of individuals currently have myopia, with a projected rise in high myopia (–5.00 dioptres or more)(Holden et al, 2016).
While genetics takes hundreds of years and numerous generations to change, the rapid rise of myopia strongly suggests that environmental and lifestyle factors, for example time spent outdoors, are at play (Tedja et al, 2019). With mixed opinion and evidence, what advice and action should optometrists take to manage myopia as well as limit associated pathologies in later life?
“Children are born hyperopic and become emmetropic through a process that regulates axial eye growth to match the eye’s focal length with its focal power. Myopia occurs when the eye fails to maintain its emmetropic state and is not a failure of the emmetropisation process,” explains Sayantan Biswas, an optometrist and myopia researcher at Aston University. He adds that the earlier the onset of myopia, the higher the risk for high myopia and associated sight-threatening conditions later in life: “Delaying the onset of myopia may delay or prevent pathological myopia.”