Ophthalmic – Glaucoma Agents

• Beta blockers
• Prostaglandin analogs
• Alpha-adrenergic agonists
• Carbonic anhydrase inhibitors
• Rho kinase (ROCK) inhibitors
• Fixed Combination Medications
• Preservative-Free Products
• Benzalkonium chloride (BAK)-Free products
• Comparative effectiveness of glaucoma drops
• New Selection tool

Background

          Primary open-angle glaucoma (POAG), is the most common form of glaucoma in the United States with an estimated 2.7 million people affected.  The risk of the disease increases with age and it is the leading cause of blindness in African Americans, who are three to four times more likely than Caucasians to have the disease.  Open-angle glaucoma develops slowly over time and it usually affects peripheral vision first, followed by central vision, and eventual permanent blindness if not treated. Risk factors for glaucoma include increased intraocular pressure, a family history of the condition, and high blood pressure.   If treated early, it is possible to slow or stop the progression of the disease.

Key points

• The goal of topical therapies is to preserve visual function by lowering intraocular pressure (IOP) below a level that is likely to produce further damage to the optic nerve.
• The growth in available agents for the medical treatment of glaucoma has increased dramatically over the years.
• It is important to note that no individual medication can be used in all patients in all circumstances.  The goals of therapy are preserving function with the lowest risk, fewest adverse or undesirable effects, and least disruption of the patient's life.
• An initial reduction in the intraocular pressure of 20% from baseline is suggested.
•  Patients with more advanced disease on initial presentation require lower initial reductions to prevent further progression and vision loss.
• The reduction of IOP to the target pressure range does not guarantee that progression will not occur. Therefore, the target pressure range needs to be constantly reassessed and changed as dictated by IOP fluctuations, optic nerve changes, and/or visual field progression.
• Generic versions of these topical products do not have to prove bioequivalence or equal effectiveness. Data is generally not available for guidance on selection.
• Topically administered glaucoma medications can have significant systemic absorption.  Patients must be instructed on the proper administration techniques to reduce the risk of systemic adverse effects.

Instillation Techniques

Steps

1. Start by tilting your head backward while sitting, standing, or lying down. With your index finger placed on the soft spot just below the lower lid, gently pull down to form a pocket.
2. Look up. Squeeze one drop into the pocket in your lower lid. Don't blink, wipe your eye, or touch the tip of the bottle on your eye or face.
3. Close your eye - helps the medication penetrate the eye (increased intraocular levels). Keep closed for two to three minutes without blinking.   Closing the eye also decreases the systemic absorption of the drug.
4. Optional: Gently press on the inside corner of your closed eyes with your index finger and thumb (nasolacrimal occlusion) for two to three minutes.  Further reduction in possible systemic absorption or draining into the throat area.
5. Finally,  blot around the eyes to remove any excess medication.

Follow up

Have the patient demonstrate the proper technique of drop instillation
on a subsequent visit.