Myopia is said to be caused by an elongation of the eyeball. This means that the oblong (as opposed to normal spherical) shape of the myopic eye causes the cornea and lens to focus at a point in front of the retina.
1 Bonds pay interest every six months until they mature. When a bond matures, the owner is paid the face value of the bond. 2  Bonds can be held until maturity or sold before maturity.  More about Treasury bonds rates and terms in the Research Center.
The bonds issued during this eight-year period earn an interest rate during each six-month rate period that is 90% of the average yield for five-year Treasury securities in the previous November-April or May-October period.