A recent publication by our laboratory has shown that patients with ocular hypertension (OHT) have reduced uveoscleral outflow and reduced trabecular outflow facility compared with healthy age-matched controls. These changes are the cause of the elevated intraocular pressure (IOP). Aqueous flow rate did not change in these patients. It is logical to assume that it would be more efficacious to treat OHT patients with drugs that reduce IOP by increasing uveoscleral outflow (which is abnormally low) than with drugs that reduce aqueous flow (which is normal in OHT).