SRP reverses presbyopia and increases the baseline tension of the ciliary muscle, which increases the trabecular meshwork pore size. Caution should be used. This procedure is an investigational device and, as such, is limited by US law to investigational use. Ocular hypertension and POAG are caused by a decrease in aqueous outflow.
Aqueous outflow is controlled predominantly by trabecular meshwork pore size.
Davanger examined the relationship of pore size to intraocular pressure using a hydrodynamic model. He found that as pore size decreases, intraocular pressure increases according to a hyperbolic function as shown in Picture 2 . Because the crystalline lens equatorial diameter increases throughout life, the baseline tension on the ciliary muscle decreases with age. A simple analogy can be made to the change in the baseline tension of the biceps muscle as the forearm is moved passively from the extended to the flexed position. Although the ciliary muscle generally is considered to be smooth muscle, it resembles skeletal muscle, and as the crystalline lens equatorial diameter increases with age, the baseline tension of the ciliary muscle is decreased.