The human eye is an extremely sensitive and versatile optical instrument. As mentioned previously, the average human eye can detect electromagnetic radiation which has wavelengths in the approximate region from 400 nm (violet) to about 700 nm (red). Recall that light, or EM radiation, is really an oscillating wave of electric and magnetic fields. As with most optical detection instruments, the human eye is primarily sensitive to the electric field component of the radiation.
In this lecture, we will discuss the physiology and optical make-up of the human eye, and then discuss the most common vision defects along with how these defects can be corrected using corrective lenses (eyeglasses).