The exact cause of nearsightedness is not completely understood, but several factors contribute to this refractive error, which is characterized by clear eyesight up close but blurry distance vision.
Researchers who study nearsightedness have identified at least two key risk factors for developing the refractive error.
Genetics
More than 150 myopia-prone genes have been identified in recent years. One such gene alone may not cause the condition, but people who carry several of these genes have a much higher risk of becoming nearsighted.
Nearsightedness — along with these genetic markers — can be passed along from one generation to the next. When one or both parents are nearsighted, there’s a greater chance that their children will develop myopia.
Vision habits
Genes are just one piece of the myopia puzzle. Nearsightedness can also be caused or worsened by certain vision tendencies — specifically, focusing the eyes on objects up close for extended periods of time. This includes consistent, long hours spent reading, using a computer, or looking at a smartphone or tablet.
When the shape of your eye doesn’t allow light to focus correctly on the retina, eye experts call this a refractive error. Your cornea and lens work together to bend light onto your retina, the light sensitive part of the eye, so that you can see clearly. If either your eyeball, cornea or your lens isn’t the right shape, light will bend away from or not focus directly on the retina as it normally would.
If you are nearsighted, your eyeball is too long from front to back, or your cornea is too curved or there are problems with the shape of your lens. Light coming into your eye focuses in front of the retina instead of on it, making faraway objects look fuzzy.
While existing myopia typically stabilizes sometime during early adulthood, the habits children and adolescents establish before then can worsen nearsightedness.
Post time: Feb-18-2022