“Pharmacologic or medical trabeculectomy” is a term first used in the 1970s. This describes a process by which the trabecular meshwork can be biochemically manipulated in order to reduce the outflow resistance and, thus, the intraocular pressure (IOP).
In cases of primary open angle glaucoma and normal-tension glaucoma , the IOP can be controlled by either reducing the inflow of aqueous humor into the eye or by increasing the outflow. Most of the medications in use now reduce aqueous production or the aqueous egress through the unconventional uveoscleral pathway.
According to one school of thought, decreasing the aqueous production and thus reducing aqueous outflow through the trabecular meshwork will progressively be detrimental to the trabecular function. This could be further accelerated by concurrent usage of prostaglandin analogs, which direct aqueous away from the meshwork to the ciliary body.
In order to overcome this, and to develop a new line of approach to the management of glaucoma, interest is focusing on the trabecular outflow pathways, and the modulation of which, can be used to reduce IOP.
In this review we take a look at the agents that have been investigated to improve the facility of aqueous outflow.