Question

what is myopia? state two reasons due to which this defect is caused.

Answer 1

Myopia (also called nearsightedness) is the most common cause of impaired vision in people under age 40 — and in recent years, its prevalence is growing at an alarming rate.Myopia occurs when the eyeball is too long, relative to the focusing power of the cornea and lens of the eye. This causes light rays to focus at a point in front of the retina, rather than directly on its surface.

Nearsightedness also can be caused by the cornea and/or lens being too curved for the length of the eyeball. In some cases, myopia is due to a combination of these factors.

Myopia typically begins in childhood and you may have a higher risk if your parents are nearsighted. In most cases, nearsightedness stabilizes in early adulthood but sometimes it continues to progress with age.

Answer 2

Myopia (also called nearsightedness) is the most common cause of impaired vision in people under age 40 — and in recent years, its prevalence is growing at an alarming rate.

A few decades ago, only about a quarter of Americans had myopia. Today, more than 40 percent of the U.S. population is nearsighted.

Globally, research suggests that back in 2000, roughly 25 percent of the world's population was nearsighted — but by the year 2050, it's expected that roughly half the people on the planet will be myopic.

Myopia occurs when the eyeball is too long, relative to the focusing power of the cornea and lens of the eye. This causes light rays to focus at a point in front of the retina, rather than directly on its surface.

Nearsightedness also can be caused by the cornea and/or lens being too curved for the length of the eyeball. In some cases, myopia is due to a combination of these factors.

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