Myopia (nearsightedness), is the most common refractive error of the eye, and it has become more prevalent in recent years. The exact cause for this increase in nearsightedness is unknown, many eye doctors feel it has something to do with eye fatigue from computer use and other extended near vision tasks, coupled with a genetic predisposition for myopia. If you are nearsighted, you typically will have difficulty reading road signs and seeing distant objects clearly, but will be able to see well for close-up tasks such as reading and computer use.
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 can also be caused by the cornea and/or lens being too curved for the length of the eyeball. In some cases, myopia occurs 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.
Most people with myopia are below -6.00D, but some people have much higher levels of myopia. How high your myopia is can be a sign of whether it may lead to further problems with your eyes. Most people with myopia of less than -6.00D don’t develop any further problems and the blurriness their myopia causes is easily dealt with by glasses or contact lenses. This is sometimes known as simple myopia.
Degenerative myopia (also called pathological or malignant myopia) is a rare and mostly inherited type of myopia that begins in early childhood. In degenerative myopia, the eyeball elongates rapidly and causes severe myopia, usually by the teenage or early adult years. Degenerative myopia may also progress far into the adult years. People with the condition have a significantly increased risk of retinal detachment and other degenerative changes in the back of the eye, including choroid neovascularization (abnormal blood vessel growth), and glaucoma.
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