Posterior capsule opacification (PCO) is the most common complication after cataract surgery, with an incidence of 30%. It tends to be considered a normal event in the natural history of cataract surgery. Better understanding of its pathophysiology and advancement of intraocular lens material and design along with the improvement of phacoemulsification technique have contributed to decrease the incidence of PCO. Although treatment by Nd: YAG laser posterior capsulotomy is quick and non-invasive, the opening of the posterior capsule may be associated with numerous complications. Prevention remains the best measure for controlling this pathology.