Posterior capsule opacification is a common postoperative complication after extracapsular cataract extraction and lens implantation. If the patient's visual acuity is reduced markedly, a capsulotomy with a Nd-YAG laser may become necessary. Various attempts have been made with the aim of developing an injectable solution capable of damaging the epithelial cells of the capsule bag irreversibly and thereby avoiding posterior capsule opacification. This solution should be applied for a short time during the operation. In tissue culture we tested the influence of two injectable solutions [lens epithelial necrosis factor (LENF)] and aqua bidest. on cellular growth. Balanced salt solution served as control. We used human epithelial carcinoma cells, type HEp-2. The results were evaluated by vital staining (ethidium bromide and acridin orange), hemotoxylin staining, autoradiography and measurement of protein and DNA synthesis. The results showed that LENF is capable of damaging 100% of the epithelial cells irreversibly if it is applied for 20 s or longer. The influence of each of these solutions was tested on 20 human capsular flaps, which were excised during the operation. The flaps were immersed for 30 s in the different solutions. Vital staining of these flaps led to the following results: LENF causes a 100% cell damage of all epithelial cells of the capsular flaps. No vital cells remained. On the other hand Aqua bidest. cannot guarantee 100% cell damage of the capsular flap epithelia. Sixty percent of the capsular flaps treated with aqua bidest, showed differing amounts of remaining vital cells.