Cataract surgery has long been known for its side benefit of lowering IOP for patients with glaucoma. While that’s still true, it may not help as much as you might think, according to a new community-based study. However, the evidence is mounting  The evidence is mounting The researchers noted that surgeons should expect IOP to fall by approximately 1mm Hg to 2mm Hg with phacoemulsification in patients with preoperative IOP less than 20mm Hg.

The researchers measured IOP in 16,169 matched pairs of patients with glaucoma who underwent phacoemulsification and patients who did not, for up to 36 months post-op.

They found the average IOP was lower in the surgery group compared with controls throughout the 36 months of follow-up. The difference was greatest in the first 18 months, during which IOP increased by 0.22mm Hg in the average non-phaco patient and decreased by 0.99mm Hg in the average phaco patient. They also noted that the average difference was greatest for patients with ocular hypertension (2.00mm Hg) and for patients with preoperative IOP ≥20 (2.46mm Hg).

By 30 to 36 months, 5% fewer cataract patients used an ophthalmic medication. In the phaco group, the odds of selective laser trabeculoplasty was reduced for those with ocular hypertension or glaucoma suspect, while the odds of glaucoma surgery were elevated in surgical patients with primary open-angle glaucoma.