Chen S, Waxman S, Wang C, et al. - In the present study, the researchers sought to describe the effects of netarsudil, a Rho-kinase inhibitor, on the aqueous humor outflow tract distal to the trabecular meshwork (TM). They assumed that netarsudil increases the outflow facility in eyes with and without circumferential ab interno trabeculectomy (AIT) that removes TM. Sixty-four cultures from the anterior segment of the porcine were randomly allocated to groups with (n = 32) and without circumferential AIT (n = 32). Cultures have been exposed to 0.1, 1, and 10 μM netarsudil (N = 8 eyes per concentration). According to findings, netarsudil at 1 μM decreased IOP both in eyes with TM (− 0.60 ± 0.24 mmHg) and in eyes without TM (− 1.79 ± 0.42 mmHg). Vessels of the distal outflow tract dilated by 72% at this concentration. However, at 0.1 μM netarsudil elevated IOP in eyes with TM (1.59 ± 0.36 mmHg) and in eyes without TM (0.23 ± 0.32 mmHg). The dose-dependent IOP changes caused by netarsudil matched the diameter changes of distal outflow tract vessels in the porcine anterior segment culture. After TM removal, hyper- and hypotensive properties of netarsudil continued.