Netarsudil works by which mechanism?

• A. Increases aqueous humor production
• B. Increases trabecular outflow and decreases episcleral venous pressure
• C. Decreases ciliary body blood flow
• D. Causes cycloplegia

Answer: (B)

Netarsudil lowers intraocular pressure by increasing trabecular outflow and reducing episcleral venous pressure. As a rho-kinase inhibitor, it relaxes cells in the trabecular meshwork and Schlemm’s canal, which lowers resistance to drainage through the conventional outflow pathway. At the same time, it lowers episcleral venous pressure, the downstream pressure against which aqueous humor must drain. Lowering this venous pressure reduces the pressure gradient driving drainage, further boosting outflow. The net effect is decreased IOP.

This isn’t achieved by increasing aqueous humor production, decreasing ciliary body blood flow, or causing cycloplegia, so those mechanisms don’t fit how netarsudil works.