The power of accommodation of the eye is the ability of the eye lens to adjust its focal length so that it can focus on near and far objects clearly on the retina. The ciliary muscles help in changing the shape of the lens by compressing and elongating it, which changes the focal length of the eye lens. The power of accommodation of the eye is limited, which means that the focal length of the eye lens cannot be reduced beyond a certain minimum limit. The standard power of accommodation for normal eyesight is measured in diopters, which is a unit of refractive power and is equal to the reciprocal of the focal length in meters. The power of accommodation for a person with normal eyesight is around 4 diopters.