Cataract Surgery and Effect on Intraocular Pressure for Open-Angle Glaucoma

As the population ages worldwide, the prevalence of cataract and glaucoma combined has been increasing. It is well known that phacoemulsification with intraocular lens implantation lowers intraocular pressure (IOP) and the number of IOP-lowering medications required by the patient. Reduction in IOP seems to be greater in patients with closed-angle glaucoma than in patients with primary open angle glaucoma. Variation in the reduction of IOP can also be explained by some preoperative predictors including higher IOP before phacoemulsification, anterior chamber depth, lens thickness, lens vault, angle open distance, gonioscopy score, and iris thickness. Possible mechanisms of IOP reduction are mechanical influence of the lens removal, increased uveoscleral outflow, and increased trabecular outflow. An increasing number of studies suggest that cataract surgery, combined with MIGS, increases the effects in IOP reduction. Nonetheless, infrequent complications related to glaucoma after phacoemulsification have been reported. The most relevant are IOP spike after surgery, long-term IOP increase, the need for further glaucoma surgery, and the need for an increased number of glaucoma medications.