As a model for our study we selected 11 pseudophacic patients with secondary cataracts who experienced good postoperative visual acuity after extracapsular cataract extraction. Besides best visual acuity and contrast sensitivity Pattern-ERG (PERG) and Contrast-Transfer-Ratio (CTR) were measured before and after YAG-Kapsulotomy was performed. Visual acuity and contrast sensitivity increased in all patients after treatment, whereas CTR increased in eight patients. PERG was measured in five patients, in two cases its amplitudes were higher, the other measurements revealed unchanged or lower amplitudes. Our model shows that in addition to the usual psychophysic tests, with CTR and PERG there are objective methods available to measure discrete opacities of the visual system.