Some accounts claim that the Roman emperor Nero ( AD 37-68 ) would gaze through an emerald in order to see gladiator fights more clearly. Nero's jewel is believed to be one of the earliest remedies for nearsightedness, a common vision condition in which one can see nearby objects clearly but things that are farther away appear blurry.
Some one in three Americans suffers from nearsightedness, which is also known as myopia. The changes that cause the problem usually begin in childhood and progress until about age 20. Most often, the cornea, which is the clear cover on the front of the eye, becomes too curved. As a result, the light that enters the eye doesn't focus properly, which makes objects in the distance appear blurred. Genetics usually dictates whether someone develops myopia, although research suggests that the stress of too much close work, such as reading small type or staring at a computer screen on a regular basis, can exacerbate the condition.
Nearsightedness can range from mild cases, in which people can see objects several feet away, to more severe instances, in which people can clearly see only objects that are a few inches away. Refractive lenses in glasses and hard or soft contact lenses are easy and inexpensive ways to corrcet this vision problem. Surgery can also reshape the cornea to improve vision. Some of the most common eye procedures include laser-assisted in situ keratomileusis, photorefractive keratectomy, and anterior intraocular lens implants.
Contrary to popular belief, sitting too close to the television or reading in dim lighting does not increase the risk of nearsightedness.
If you don't wear glasses or contacts and have no eye trouble, experts recommend having an eye exam once between the ages of 20 and 39, every 2 to 4 years from age 40 to 64, and every 1 to 2 years beginning at age 65.
안경이나 콘택트를 착용하지 않고 시력 문제가없는 경우 전문가는 20 세에서 39 세 사이, 40 세에서 64 세 사이의 2-4 년마다, 그리고 65세의 나이부터 시작하여 1-2 년마다 한번씩 시력 검사를받는 것이 좋습니다.
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