Cataract extraction yielded a long-term reduction in IOP in patients with ocular hypertension, according to data culled from the Ocular Hypertension Treatment Study.
“By using the [Ocular Hypertension Treatment Study] dataset, with its careful method for measuring IOP, we have confirmed the general results of previous studies and provide important new information about the magnitude and duration of the IOP-lowering effect of phacoemulsification in eyes with elevated IOP,” the study authors said.
The comparative case series included 63 eyes of 42 patients who underwent cataract extraction. A control group comprised 743 eyes of 743 subjects who did not have cataract surgery.
Mean patient age was 64.1 years in the cataract surgery group and 55 years in the control group.
The investigators determined a “split date,” a point at which cataract surgery was reported in the study group and a corresponding date was set in the control group.
The primary outcome measures were differences in preoperative and postoperative IOP.
Mean preoperative IOP in the surgery group was 23.9 mm Hg. In the control group, mean IOP before the split date was 23.8 mm Hg.
Postoperative IOP in the surgery group was 19.8 mm Hg; the decrease from preoperative IOP was statistically significant (P < .001).
In the surgery group, postoperative IOP was lower than preoperative IOP for at least 36 months. The average decrease in IOP was 16.5%; postoperative IOP was at least 20% lower than preoperative IOP in 39.7% of eyes.
Eyes with the highest preoperative IOP had the most reduction in postoperative IOP.
Mean IOP in the control group after the split date was 23.4 mm Hg.