Background: Decreasing intraocular pressure (IOP) and preventing the IOP rising during cataract surgery, is one of the most important factors in successful cataract surgery. This study was conducted to investigate the effects of intravenous lidocaine on IOP in cataract surgery under sedation.Methods: The study was a double blind controlled trial which firstly, the patient’s IOP was measured. Then the patients were divided into two groups. The lidocaine (experimental) group had injected intravenous lidocaine and the control group had injected intravenous saline. Three minutes later after intervention, IOP was measured again. The data was analyzed using SPSS 15 software and Chi-square, independent t-test and Mann-Whitney tests.Results: Mean age of participants was 56.6 (±9.7) years. The mean of IOP difference after and before intervention was -1.06(±3.96) mmHg (median: 0 and range: -15 to 2) and there was no significant statistical difference between two groups but it decreased more in those with higher pre-intervention intraocular pressure in lidocaine group.Conclusion: A dose of 1.5 mg/kg of intravenous lidocaine may reduce intra ocular pressure of patients who have increased pre-operation IOP. In addition, lidocaine might be used when IOP increases suddenly during eye surgeries that are performed under sedation.