In the United States, in 1971, only 25% of the population was nearsighted. By 2004, that number had risen to 42%. If current trends continue, it is estimated that half of the world’s population will be nearsighted by 2050.
For decades, researchers believed that whether or not you needed glasses was a genetic issue. Having one parent who is nearsighted doubles your chances of being nearsighted, and if both parents are affected, your risk increases fivefold. However, human genetics do not change that rapidly.
The sudden increase in nearsightedness is due to environmental factors. (Illustrative image).
This sudden increase is attributed to environmental factors. There are two key influences. Time spent focusing on close objects and time spent indoors.
In a healthy eye, the muscles must contract the lens to focus images at close range onto the retina. Some experts hypothesize that if your eye grows and strains to see things up close, it will elongate to alleviate that strain.
A more common cause is the time spent indoors. Exposure to outdoor light stimulates the production of dopamine in the retina. This neurotransmitter regulates eye development; without enough dopamine, the eye does not know when to stop growing, and it is difficult to have an adequate amount indoors. Sunlight can reach up to 100,000 lux on a sunny day, while indoor light levels generally hover around 200 to 300 lux.
With the rise of electronic devices and a growing emphasis on studying, eye care experts believe that today’s children are growing up in conditions with too little daylight and spending too much time doing things at close range.
In the long term, the consequences of distorted eyeball shape can become severe. Professor Mark Bullimore, an optometry expert at the University of Houston, explains: “You see, you are born with a finite amount of tissue that makes up the different layers of the eyeball. Excessive elongation simply puts more pressure on those structures. The retina has been stretched to the point where it starts to tear and then peels off like an old paint chip. The longer the eye is elongated, the higher the risk of developing disorders like myopic macular degeneration.“
