Open Angle Glaucoma: Treatment

Recall that in open-angle glaucoma, the stiff trabecular meshwork impedes the aqueous humor outflow, increasing intraocular pressure.

It is treated by reducing aqueous humor secretion or improving aqueous humor outflow to lower the intraocular pressure.

To decrease humor secretion, drugs acting on adrenergic receptors of the ciliary body  are commonly used.

For instance, brimonidine binds to α₂-adrenergic receptors. While timolol binds to both β₁ and β₂ receptors on the ciliary epithelium.

In addition, carbonic anhydrase inhibitors, such as brinzolamide, are also used to decrease aqueous humor secretion.

Alternatively, to increase aqueous humor outflow, cholinomimetic drugs, such as pilocarpine, bind to muscarinic receptors and stimulate ciliary muscle contraction, thereby lowering intraocular pressure.

Similarly, rho kinase inhibitors and prostaglandins also enhance the outflow and lower intraocular pressure.

These drugs are administered topically as eye drops.

However, they may exert several side effects. For example, brimonidine can cause sleepiness, timolol may lead to bronchoconstriction, and pilocarpine may weaken vision.