Aqueous Humor Flow in Normal Human Eyes Treated With Brimonidine and Timolol, Alone and in Combination

Effect of Timolol on Aqueous Humor Outflow Facility in Healthy Human Eyes

“…Of note, the 1 μL/min flow rate threshold identified by Johnson is lower than the nocturnal flow rate in humans, when aqueous humor production decreases by approximately 50% 38 and lower than the flow rate typically achieved with timolol eye drops. 4,5,[16][17][18][19][20][21] Another possible explanation for the reduction in outflow facility by timolol is that changes in outflow facility in response to decreased aqueous humor flow are not pathologic, but are instead pressure regulatory mechanisms. Acott et al 39 hypothesized and reviewed the evidence that resistance within the conventional outflow pathway is continually adjusted in response to cell stretch from sustained IOP changes.…”

Effect of Timolol on Aqueous Humor Outflow Facility in Healthy Human Eyes

“…Of note, the 1 μL/min flow rate threshold identified by Johnson is lower than the nocturnal flow rate in humans, when aqueous humor production decreases by approximately 50% 38 and lower than the flow rate typically achieved with timolol eye drops. 4,5,[16][17][18][19][20][21] Another possible explanation for the reduction in outflow facility by timolol is that changes in outflow facility in response to decreased aqueous humor flow are not pathologic, but are instead pressure regulatory mechanisms. Acott et al 39 hypothesized and reviewed the evidence that resistance within the conventional outflow pathway is continually adjusted in response to cell stretch from sustained IOP changes.…”

Brimonidine and Timolol Fixed-Combination Therapy Versus Monotherapy: A 3-Month Randomized Trial in Patients with Glaucoma or Ocular Hypertension

“…These findings are consistent with earlier studies that suggested that the concomitant use of brimonidine and timolol provided greater IOP lowering that did either drug administered separately. 20,21,23,25 A formulation of brimonidine 0.15% preserved with Purite ® (Alphagan ® P, Allergan, Inc.; Irvine, CA) is available in the United States. This formulation shows equivalent efficacy and improved tolerability compared with brimonidine 0.2% preserved with benzalkonium chloride (BAK).…”

Ocular Drug Delivery into the Eyes Using Drug-Releasing Soft Contact Lens

“…Moreover, α-adrenergic agonists such as brimonidine bind α-adrenergic receptors on the surface of ciliary epithelial cells and consequently reduce aqueous humor secretion. Intriguingly, a combination of brimonidine and β-blockers such as timolol reduced the intraocular pressure by 15.4% greater than the contralateral timolol-treated eye in a randomized, double-masked, placebo-controlled study of 20 human subjects [56].…”

“…There are three targets for drug therapy for dry eye: the lipid layer, the aqueous/mucus layer, and the corneal epithelium [56,61]. Mild symptoms can be improved with eye drops.…”

Effect of Timolol on Aqueous Humor Outflow Facility in Healthy Human Eyes

“…Of note, the 1 μL/min flow rate threshold identified by Johnson is lower than the nocturnal flow rate in humans, when aqueous humor production decreases by approximately 50% 38 and lower than the flow rate typically achieved with timolol eye drops. 4,5,[16][17][18][19][20][21] Another possible explanation for the reduction in outflow facility by timolol is that changes in outflow facility in response to decreased aqueous humor flow are not pathologic, but are instead pressure regulatory mechanisms. Acott et al 39 hypothesized and reviewed the evidence that resistance within the conventional outflow pathway is continually adjusted in response to cell stretch from sustained IOP changes.…”

Brimonidine and Timolol Fixed-Combination Therapy Versus Monotherapy: A 3-Month Randomized Trial in Patients with Glaucoma or Ocular Hypertension

“…These findings are consistent with earlier studies that suggested that the concomitant use of brimonidine and timolol provided greater IOP lowering that did either drug administered separately. 20,21,23,25 A formulation of brimonidine 0.15% preserved with Purite ® (Alphagan ® P, Allergan, Inc.; Irvine, CA) is available in the United States. This formulation shows equivalent efficacy and improved tolerability compared with brimonidine 0.2% preserved with benzalkonium chloride (BAK).…”

Ocular Drug Delivery into the Eyes Using Drug-Releasing Soft Contact Lens

“…Moreover, α-adrenergic agonists such as brimonidine bind α-adrenergic receptors on the surface of ciliary epithelial cells and consequently reduce aqueous humor secretion. Intriguingly, a combination of brimonidine and β-blockers such as timolol reduced the intraocular pressure by 15.4% greater than the contralateral timolol-treated eye in a randomized, double-masked, placebo-controlled study of 20 human subjects [56].…”

“…There are three targets for drug therapy for dry eye: the lipid layer, the aqueous/mucus layer, and the corneal epithelium [56,61]. Mild symptoms can be improved with eye drops.…”

Effect of Timolol on Aqueous Humor Outflow Facility in Healthy Human Eyes

“…Of note, the 1 μL/min flow rate threshold identified by Johnson is lower than the nocturnal flow rate in humans, when aqueous humor production decreases by approximately 50% 38 and lower than the flow rate typically achieved with timolol eye drops. 4,5,[16][17][18][19][20][21] Another possible explanation for the reduction in outflow facility by timolol is that changes in outflow facility in response to decreased aqueous humor flow are not pathologic, but are instead pressure regulatory mechanisms. Acott et al 39 hypothesized and reviewed the evidence that resistance within the conventional outflow pathway is continually adjusted in response to cell stretch from sustained IOP changes.…”

Brimonidine and Timolol Fixed-Combination Therapy Versus Monotherapy: A 3-Month Randomized Trial in Patients with Glaucoma or Ocular Hypertension

“…These findings are consistent with earlier studies that suggested that the concomitant use of brimonidine and timolol provided greater IOP lowering that did either drug administered separately. 20,21,23,25 A formulation of brimonidine 0.15% preserved with Purite ® (Alphagan ® P, Allergan, Inc.; Irvine, CA) is available in the United States. This formulation shows equivalent efficacy and improved tolerability compared with brimonidine 0.2% preserved with benzalkonium chloride (BAK).…”

Ocular Drug Delivery into the Eyes Using Drug-Releasing Soft Contact Lens

“…Moreover, α-adrenergic agonists such as brimonidine bind α-adrenergic receptors on the surface of ciliary epithelial cells and consequently reduce aqueous humor secretion. Intriguingly, a combination of brimonidine and β-blockers such as timolol reduced the intraocular pressure by 15.4% greater than the contralateral timolol-treated eye in a randomized, double-masked, placebo-controlled study of 20 human subjects [56].…”

“…There are three targets for drug therapy for dry eye: the lipid layer, the aqueous/mucus layer, and the corneal epithelium [56,61]. Mild symptoms can be improved with eye drops.…”