Intraocular lenses are used to correct nearsightedness, farsightedness, astigmatism and cataracts. To treat cataracts, the cloudy lens is first removed and then replaced with plastic lenses. But to correct myopia, the lens of the eye remains intact and a flexible lens is implanted through a small slit in front of the eye lens. Phakic intraocular lenses (PIOL) are used to correct farsightedness, nearsightedness and high astigmatism.