Modern medical technology and devices have paved the way for identifying and treating diseases in their early stages but often does not dampen their occurrence in a population. Whilst you would not consider myopia, commonly known as short sight, as a medical condition, its prevalence is also increasing. The incidence of short sight is estimated at 30-40% of the population of Europe and the United States and up to 90% in some countries in Asia.
What might be the reason for this increasing prevalence?
Genes versus environment
Any condition or trait can be affected by your genes or the environment in which you live, and sometimes the two interact with each other. It is likely in the case of short sight that its increased occurrence is related to the two. Twin studies are often used to pick apart the relationship between genes and the environment in determining a trait. For a strong genetic component, the incidence in identical twins is higher than in non-identical twins raised in the same environment and similar in identical twins raised apart. Read also The Benefits of Scalp Massages for Healthier Hair.
However, differences in twins raised apart can indicate the impact of the environment. Indeed twin studies do indicate that there is a strong genetic component to myopia, but that the environment is also likely to play a role. The main environmental factor usually cited as the cause of increasing short sight seen in children in recent generations is an increase in reading in the young and work were done at a too close distance. Whilst the majority of children in industrialized nations undertake close work during their education, only a quarter to a third of these children typically develops short sight, so this is another piece of evidence for a genetic influence.
When humans were hunter-gatherers, the ability to see at distance was important for survival, both to be able to identify potential prey and threats. In these times, individuals with good eyesight were more likely to survive and reproduce, therefore passing their genes on to their children. This natural selection of those with favorable eyesight follows Darwin’s principle of natural selection.
However, in many modern societies where there is a plentiful supply of food that can be purchased from the supermarket and where threats are greatly diminished, perfect vision is no longer essential. Therefore as short sight is not in the equation now for survival, individuals with myopia are just as likely to have their own children, leading to an increase in the number of people carrying the specific genetic defects predisposing to short sight.
The impact of vision correction
While there is no denying that the inability to see at distance will still cause various problems and make certain tasks more difficult or impossible in modern life – reading from a board, watching the television or driving for instance – it is thanks to opticians and optometrists that even these problems can be eliminated.
Where would those of us with short sight be without our glasses or contact lenses?
We have become so reliant on devices to correct our vision that it is hard to imagine how we would now manage without them. No doubt we would struggle, so hopefully, we will never have to deal with this situation.
Have we become a victim of our success regarding the correction of short sight?
While it is difficult to know whether the use of glasses and contact lenses is hastening the deterioration of vision in our populations, it is certainly an interesting thought on which to ponder and an area into which further scientific research will likely be conducted. That said, even if found to be the case, no one is ever going to suggest that we should stop correcting people’s sight, as where would that leave us?