Glaucoma

Question 1

Question

Nitric oxide has been shown to lower intraocular pressure by which of the following mechanisms?

Increasing outflow through the trabecular pathway
Decreasing aqueous humor production through active secretion
Decreasing aqueous humor production through ultrafiltration
Increasing outflow through the uveoscleral pathway

Answer 1

Increasing outflow through the trabecular pathway

Explanation
Nitric oxide is a component of a new glaucoma medication known as Latanoprostene bunod (which also contains the prostaglandin analogue latanoprost). Latanoprost decreases intraocular pressure (IOP) by enhancing uveoscleral outflow, while nitric oxide lowers IOP through direct action on the trabecular meshwork. The mechanism of action involves the relaxation of cells in the trabecular meshwork and Schlemm’s canal via rearrangement of actin-myosin interactions by decreasing myosin phosphorylation. This leads to increased aqueous humor outflow and reduction of IOP.