FIGURE 9.

Pressure-dependent outflow system tissue motion and flow. Schematic depiction of outflow structure pressure-dependent motion and related outflow oscillating around a mean setpoint (Supplementary Video 4). (A–E) Depict trabecular meshwork (TM) distention into SC in response to a pressure increase. (F–J) Depict recoil from the distended configuration. As IOP increases (B), the TM and juxtacanalicular region (JCR) progressively enlarge, decreasing SC dimensions. SIV connect the TM to septa that appear as hinged flaps (HF), where they connect to CC entrances. The SIV is obliquely oriented within the circumference of SC. Outward TM motion can cause the SIV to induce tension on the septa and hinged flaps at collector channels (CC). Thin mobile septa provide a barrier between SC and circumferential vascular channels (CVC) adjacent to the canal. As pressure falls, the CVC progressively closes with a resulting increase in resistance (R), as noted in (H). The resulting behavior permits the CVC region to act like an SC outlet valve-like structure (SOV). Progressive closure reduces inward flow from SC and outward flow to radially oriented intrascleral vessels (RISC). IOP-dependent TM movement can act as a sensor controlling the SOV configuration, thereby providing a feedback loop to control IOP. Minimal linear TM motion may amplify flow resistance because of Poiseille’s law. White arrows depict one possible aqueous flow sequence. All aspects of the model are provisional and subject to modification.