Drugs classified as beta-blockers have proved to be valuable in the treatment of patients with glaucoma. Timolol has become the most widely used ocular hypotensive agent. Actual and potential side effects associated with its non-selective beta-blockade have prevented its use in patients with reactive airways disease, and to a lesser extent, with various cardiovascular conditions. Betaxolol is a relatively selective beta-1 blocker which in most patients is almost as effective as timolol in lowering intraocular pressure, and may be partly additive with dipivefrin. It is probably safer in patients unable to tolerate non-selective beta-blockers. However, it needs to be used with caution in these patients, who are unpredictably susceptible to systemic side effects.