Intoduction: UBM frequencies ranging from the 50-100 MHz. The termultrasound biomicroscopy (UBM) have been applied to this imagingtechnique because of similarities to optical biomicroscopy, i.e., theobservation of living tissue at microscopic resolution. It is a non-specificimaging technique that can be used for any ocular pathology which fallwithin its penetration limits. It was applied to image the anterior segmentstructures & provide a system for anterior segment measurementsfollowing cataract surgery. Also UBM could visualize the area posteriorto the iris & ciliary body which was difficult to be examined, soimproving greatly the diagnostic possibilities. By using UBM, we havedemonstrated the possibility of evaluating IOL implantation regarding theposition of the IOL haptics.Aim of study: the aim of our study is to identify and quantify the anteriorsegment changes following phacoemulsification and extracapsularcataract extraction by using UBM.Methods: this study included sixty eyes of fifty-eight patients hadimmature or mature cataract under went phacoemulsification (group A)and ECCE (group B) with implantation of posterior chamber IOL. UBMwas done preoperatively and postoperatively (1week, 2week and2months) for each patient. The following parameters were measured:ACD,AOD 500μ, TIA, ILA, IT at 500μ and at pupil, TCPD. Also wedetermined the IOL haptics position by UBM.Results: there is increase in postoperative values in ACD,AOD500μ,TIAin both group A and B. No increase in postoperative values in TCPD orIT. There is decrease in ILA ( absent in most cases postoperative). Ingroup A: IOL haptics in Bag (73.4%), in sulcus (23.3%), sulcus -bag(3.3%). In group B: all 30eyes IOL haptics in sulcus. No retation betweenanterior chamber angle width and position of IOL haptics.Conclusion: this study could identify and quantify the anterior segmentparameters by UBM following cataract surgery. Also UBM is an accuratemethod to determine the actual position of IOL haptics.