Postoperative disturbances of the pupil are discussed on the basis of experience with more than 2500 intraocular lenses implanted after extracapsular cataract extraction (planned extracapsular or phacoemulsification). Apart from the changes to the pupil caused by an iris-fixed intraocular lens itself, the pupil may also be affected by blood, fibrinous inflammation, or remnants of cortex material or the anterior capsule after posterior chamber lens implantation. These conditions are frequently followed by synechiae between the pseudophakia and the iris. Mechanical damage to the iris or the sphincter muscle may also occur. Changes in the shape of the pupil often affect its function, and synechiae do so regularly. Secondary cataract necessitating treatment occurred in about 10% of our patients over a 7-year period. Today, YAG laser surgery represents the best means of restoring clarity to the pupil, though there are still a number of unresolved problems with the method. Neither primary nor secondary capsulotomy after pseudophakia implantation can be recommended. The methods of extracapsular cataract extraction with posterior chamber lens implantation are still at a stage of development which is not altogether satisfactory, since optic irregularities of the pseudophakia or the central posterior capsule may result in glare, disturbing the patient in spite of good visual acuity.