Tips for understanding nearsightedness

Nearsightedness is the most common sight problem, and the most likely sight defect among young people. Here's an explanation of what nearsightedness, or myopia, is. 

• If you are nearsighted, either your eyeball is too long or your cornea is too steep, so light rays coming from a distance are bent too much. The focal point forms in front of the retina, and by the time the rays reach the retina they have spread apart again, so the image is no longer in focus.
• To someone who is nearsighted, distant objects look blurred, though those close-up are seen clearly.
• If you have been told that you have near sight (also called myopia), you probably discovered that you needed glasses during your childhood or in your teens.

• Most babies are born with a degree of farsightedness, so nearsightedness is rare before the age of five. It tends to start in late childhood, roughly between the ages of 8 and 12, but is frequently not picked up until adolescence. That is because nearsightedness develops so gradually that children don't notice that fuzzy vision is a problem or realize that their sight is any different from other people's. As a consequence, myopia is easily overlooked unless a child undergoes regular eye exams.
• It is not uncommon for nearsightedness to be picked up for the first time when a teacher notices that a child has difficulty seeing the blackboard (or, these days, the whiteboard) although he or she can read perfectly normal close-up.
• Sometimes a gym teacher may notice that a child has become less coordinated or less skilled at sports.

• Nearsightedness generally develops at any time up to the age of 25, but after that it is much less likely. The chances are that if you're over 30, you have escaped.
• If you are nearsighted, it probably got worse during the early years and stabilized in your late teens or early twenties. Myopia does not usually progress once someone has stopped growing, though the earlier it starts the more severe it is likely to be.
• Nearsightedness makes distant objects look blurred and also causes tired eyes and headaches, but it is not detrimental to your overall eye health. In fact, as you get older, you may have an advantage over your normally-sighted friends — your eyes effectively have a built-in reading prescription. You won't necessarily escape presbyopia (farsightedness) altogether, but you will probably notice it later and to a lesser extent, so you'll be able to carry on reading without glasses for longer.
• Most nearsighted people are affected to a mild or medium degree, but about one in twenty has high-degree myopia. This is associated with an increased risk of eye disorders in later life, so if your optometrist tells you that you have high-degree myopia you should be extra vigilant about reporting eye symptoms as you get older and, of course, making sure that you have regular eye exams.