Suprachoroidal space as a therapeutic target

The uveoscleral route of aqueous humor outflow has been less well characterized than the trabecular route. The two routes differ physiologically in many respects. Whereas trabecular outflow is dependent on intraocular pressure (IOP), uveoscleral outflow is mostly driven by the higher hydrostatic pressure difference in the anterior chamber relative to the suprachoroidal space (SCS). Outflow through the two routes is also differentially responsive to pharmacological interventions intended to manipulate IOP. For example, prostaglandin-based therapies target the uveoscleral route but have little effect on trabecular outflow. Injection of drugs into the SCS is being investigated as a means of delivery of small molecules and potentially sustained-release formulations of large biological molecules to the back of the eye. The uveoscleral pathway is also being increasingly targeted by diverse surgical approaches, with the potential to avoid some of the more serious complications associated with trabecular surgical interventions.