Why is myopia on the rise in the population?
The main causes of avoidable blindness in the world include refractive errors (myopia, hyperopia and astigmatism), which are more or less disabling, depending on the socio-geographical location or their extent. They entail dependence on ophthalmic or contact lenses, surgery and its ensuing costs.
With regard to myopia, the rapid increase in global prevalence in recent years and its consequences is worth mentioning, as it is one of the main risk factors for other more disabling diseases (retinal detachment, cataracts, glaucoma, etc.), which can lead to an operation, such as cataract surgery or retinal surgery.
The prevalence of myopia has even doubled over the last century. Asians are the most affected population, followed by Europeans and North Americans, from 10-20% to 80% at present, mainly in adolescents and young people. The most affected countries, such as Singapore, Hong Kong and Taiwan, have around 80% of young people with myopia, compared to 25% decades ago. In the West, it now stands at 30-50%, but is steadily increasing as well. The problem is not just ametropia, which can vary and be disabling, depending on its extent, but rather that a myopic eye is an eye with a greater risk of other disorders and even, in the most severe cases, irreversible vision loss.
Causes of increased myopia
The main cause of myopia described to date was the genetic factor, which does not explain the increase experienced in the last century, so science has gone on to study changes in lifestyle that may explain this phenomenon.
Another cause of acquired myopia that has been considered until now was prolonged reading. However, at present the time spent on other tasks at close distance is gaining more importance, whether it be a mobile phone, tablet or computer. They take up a large part of our time, either because of work or visual demands in studies, or for the leisure they provide. In short, all of the above leads to less time spent outdoors, which is becoming a factor that scientists are studying as a possible trigger of what is starting to be considered an epidemic.
Studies compare the amount of time a child spends outdoors in Singapore and Australia. In both countries, the rate of myopic adults is similar, while 29.9% of children in Singapore are myopic and in Australia 3.3%, i.e. the latter spend more time outdoors. Even how a higher incidence of light with greater outdoor exposure may affect us is being studied.
Diet and exercise do not seem to be factors that have a major impact on the progression of myopia in developing eyes. What is being studied and science seems to show is that more outdoor activities and fewer smartphones may be a good option for a society that, if left unchecked, faces an estimated 50% of myopic population by 2050, as well as the consequences this entails, both economically and in terms of social impact on quality of life.
