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Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
The U.S. Preventive Services Task Force recommends that all women age 65 years of age or older should be screened with bone densitometry.
Amoebae are the simplest type of protozoans, and are characterized by a feeding and dividing trophozoite stage that moves by temporary extensions called pseudopodia or false feet.
Illicit drug use costs the United States approximately $181 billion every year.
Side effects from substance abuse include nausea, dehydration, reduced productivitiy, and dependence. Though these effects usually worsen over time, the constant need for the substance often overcomes rational thinking.