Effect of carbachol on postoperative intraocular pressure.

Carbachol instilled in 125 eyes at the time of extracapsular cataract extraction and posterior chamber lens insertion had a statistically significant effect on lowering the postoperative intraocular pressure (IOP) at 24 hours (average IOP 14.0 mm Hg) and at 72 hours (average IOP 11.6 mm Hg) (P less than .001). The percentage of patients with an acute IOP elevation at 24 hours was also significantly reduced: carbachol 10% versus control 33% (P = .001). Carbachol's prolonged lowering of postoperative IOP may increase the safety of cataract surgery, particularly in patients with compromised optic nerves.