AIM: To compare the optical performance of the anterior surface modified prolate Tecnis Z9000 IOL with the standard 911A IOL in terms of contrast sensitivity outcomes. · METHODS: The Tecnis Z9000 silicone IOL shares the same basic characteristics with the 911A IOL including a 12.0mm overall diameter, 3-piece equiconvex 6.0mm optic and angulated cap C polyvinylidene fluoride haptics. This is a randomized prospective study that involved ten consecutive patients (20 eyes) with bilateral cataracts. Each patient underwent phacoemulsification and received randomly the Tecnis Z9000 IOL in one eye and the control (911A IOL) in the fellow eye within 6 weeks period of one another. Contrast sensitivity was measured after six postoperative weeks. The collected data were analyzed through using Mann Whitney U test. · RESULTS: The mean pre-operative best spectacle corrected Snellen visual acuity in the eyes that were randomly selected to receive the Tecnis IOL was 6/8.5 (0.70) and in the eye selected to receive the 911A IOL was 6/9.4(0.64). Postoperatively all 20 eyes achieved best corrected Snellen visual acuity of 6/6 (1.0). Postoperative contrast sensitivity testing showed statistically significant differences (P <0.05) between the two IOLs at 12 and 18 cpd under photopic, at 1.5 and 3 cpd under mesopic, and at 1.5 and 3 cpd under mesopic with glare conditions. · CONCLUSION: The Tecnis Z9000 IOL proved to have statistically significant superior contrast sensitivity to the 911A IOL at high spatial frequencies under photopic conditions and at low spatial frequencies under mesopic and mesopic with glare conditions.