Reduction in Intraocular Pressure after Cataract Extraction: The Ocular Hypertension Treatment Study

Purpose To determine the change in intraocular pressure (IOP) after cataract extraction in the observation group of the Ocular Hypertension Treatment Study. Design Comparative case series. Participants Forty-two participants (63 eyes) who underwent cataract surgery in at least 1 eye during the study and a control group of 743 participants (743 eyes) who did not undergo cataract surgery. Methods We defined the “split date” as the study visit date at which cataract surgery was reported in the cataract surgery group and a corresponding date in the control group. Preoperative IOP was defined as the mean IOP of up to 3 visits before the split date. Postoperative IOP was the mean IOP of up to 3 visits including the split date (0, 6, and 12 months' with “0 months” equaling the split date). In both groups, we censored data after initiation of ocular hypotensive medication or glaucoma surgery of any kind. Main Outcome Measures Difference in preoperative and postoperative IOP. Results In the cataract group, postoperative IOP was significantly lower than the preoperative IOP (19.8±3.2 mmHg vs. 23.9±3.2 mmHg; P