In a series of 200 consecutive senescent cataracts treated with phacoemulsification, 167(83.5%) were left with an intact posterior capsule at the initial surgery. Subsequently 35% developed an opacified capsule; the incidence rose to 50% in those patients followed for more than three years postoperatively. Polishing the posterior capsule did not prevent or delay the opacification. A secondary capsulotomy was performed in 56 cases with the Haab discission knife; no complications were directly associated with the technique.