Glaucoma

• Glaucoma is an eye disease resulting in damage to the optic nerve and loss of the visual field.
• Most cases of Glaucoma involve intraocular pressure (IOP) greater than the normal range of 12-22 mmHg.
• The goal of glaucoma treatment is to reduce IOP.
• Factors like genetics, age and medications can cause an increase in IOP.

Drugs That Can Increase IOP

• Anticholinergics like antihistamines can increase IOP.
• Oxybutynin, tolterodine, benztropine, scopolamine and tricyclic antidepressants
• Decongestants like pseudoephedrine
• Chronic steroids, especially eye drops like prednisolone (Pred Forte)
• Topiramate (Topamax)

Two Major Types of Glaucoma

• Open-Angle Glaucoma is the most common type in North America.
• Open-Angle Glaucoma often presents without symptoms and is a chronic, slowly progressive disease.
• Open-Angle Glaucoma is primarily found in patients older than 50 years.
• Visual field loss, normal or elevated IOP, and optic disk changes are all signs of Open-Angle Glaucoma.
• Eye drops and surgery are treatments for Open-Angle Glaucoma.
• Closed-Angle Glaucoma involves a sharp, sudden increase in IOP due to a blockage, requiring a medical emergency.
• Eye pain, headaches, and decreased vision are typical symptoms of Closed-Angle Glaucoma.
• Closed-Angle Glaucoma is treated surgically.
• Angle-closure glaucoma is another name for Closed-Angle Glaucoma.
• Closed-Angle Glaucoma is more prevalent in Asia.

Glaucoma Treatment Goal

• Glaucoma treatments decrease IOP by targeting the aqueous humor.
• Strategies to reduce IOP focus either on making less fluid or moving fluid out.
• Aqueous humor production can be reduced using beta-blockers (ex. timolol) and carbonic anhydrase inhibitors (ex. dorzolamide).
• Aqueous humor outflow can be increased using prostaglandin analogs (ex. latanoprost).
• Alpha-2 agonists (ex. brimonidine) can reduce fluid production and increase fluid outflow.

Patient Care Process for the Management of Glaucoma

• The Patient Care Process for Glaucoma Management involves steps: Collect, Assess, Plan, Implement, and Follow-up (Monitor and Evaluate).

Collect

• Collect patient characteristics, like age, race, sex, and pregnancy status.
• Patient history, changes in vision, current medications, and objective data are collected.
• Objective data includes IOP measurements, disc changes/abnormalities, and visual field changes/losses.

Assess

• Assess medications that may contribute to the condition, along with the patient's history of adverse effects.
• If primary Closed-Angle Glaucoma is suspected, manage or refer as an ophthalmologic emergency.
• Identify a current target IOP goal based on past history and current situation.

Plan

• The drug therapy regimen is designed to achieve the target IOP.
• Continuation and discontinuation of existing therapies should be specified.
• Monitor, at minimum, a 20% reduction in IOP (25%-30% if no reduction) from baseline 4-6 weeks after starting therapy to assess for adverse effects.
• Referrals to other providers (e.g., ophthalmologist) should be made when appropriate.

Implement

• Provide patient education regarding all elements of the treatment plan.
• Use motivational interviewing and coaching strategies to maximize adherence.
• Schedule follow-up, usually 4-6 weeks after therapy starts, and every 3-4 months once target IOPs are achieved.

Follow-up: Monitor and Evaluate

• Measure IOP; monitor the optic disc and visual fields.
• Assess adverse effects/tolerability to medications and adherence to technique.
• Poor adherence or nonadherence occurs in 25%-60% of glaucoma patients.

Medications Used in the Treatment of Open-Angle Glaucoma

• First-line recommended agents, such as Prostaglandin (PG) analogs, are most effective at decreasing IOP (~30%).
• PG analogs are generally safe, used once daily and provide better 24-hour IOP control; lower-cost generics are available.
• Ophthalmic beta-blockers are commonly used as initial treatment with a long history of successful use.
• They provide a combination of clinical efficacy and general tolerability.
• A beta-blocker is preferred if the pressure is high in one-eye-only.

Prostaglandin Analogs

• Bimatoprost (Lumigan): 1 drop QHS
• Latanoprost (Xalatan, Xelpros) + Netarsudil (Rocklatan): Do not exceed once daily dosing to avoid decreased efficacy.
• Travoprost (Travatan Z): Select products with benzalkonium chloride (BAK); remove contact lenses before use.
• Latanoprostene bunod (Vyzulta)
• Tafluprost (Zioptan)
• Bimatoprost (Latisse) is indicated for eyelash hypotrichosis: do not use with PG analogs indicated for glaucoma.
• Ocular effects of Prostaglandin Analogs: darkening of the iris, eyelid skin and eyelashes, eyelash length and number can increase.
• Side effects: blurred vision, stinging, increased pigmentation of the iris/eyelashes, eyelash growth/thickening

Beta-Blockers

• Timolol 0.25% and 0.5% (Timoptic, Timoptic-XE, Istalol, Timolol GFS, Betimol, Timoptic Ocudose): 1 drop daily or BID.
• Timolol + dorzolamide (Cosopt, Cosopt PF)
• Timolol + brimonidine (Combigan)
• Betaxolol (Betoptic S)
• Carteolol
• Levobunolol (Betagan)
• Timoptic-XE, Timolol GFS (gels): shake once before use, wait 10 minutes after eye drops before inserting gel, dosed daily.
• Contraindications: sinus bradycardia, heart block > 1st degree, cardiogenic shock, uncompensated cardiac failure, bronchospastic disease
• Side effects: burning, stinging, bradycardia/fatigue, bronchospasm, itching of eyes/eyelids, change in vision, sensitivity to light
• All are non-selective beta-blockers except betaxolol; betaxolol is less likely to cause pulmonary adverse effects in patients with chronic lung disease.

Adrenergic Alpha-2 Agonists

• Brimonidine is considered a second-line or adjunctive agent.
• Apraclonidine is generally used only short term after ocular surgery.
• Alphagan P and Lodipine are dosed TID.
• CNS depression: caution use with heavy machinery, driving.
• Side effects: sedation, dry mouth, dry nose.

Carbonic Anhydrase Inhibitors

• Dorzolamide and Brinzolamide are topical agents - Considered second line after PG analogs and beta blockers.
• Systemic CAI Agents reduce IOP by 25% to 40% and are considered third-line agents.
• Eye drops side effects: burning, blurred vision, blepharitis, dry eye.
• Oral (acetazolamide): CNS effects (ataxia, confusion), photosensitivity/skin rash

Rho Kinase Inhibitors

• Netarsudil received FDA approval on December 18, 2017 as first in its class of antiglaucoma medications with beta-blockers efficacy.
• Netarsudil/latanoprost ophthalmic solution (Rocklatan) was approved on March 13, 2019, and boasts a superior IOP reduction to either constituent alone.
• Dosed at 1 drop daily in the vending; contains the preservative BAK.
• Side Effects: burning/eye pain, corneal disease, conjunctival hemorrhage and conjunctival hyperemia.

Parasympathomimetics

• Treatment of glaucoma has decreased significantly with these agents due to local ocular adverse effects.
• Pilocarpine is the parasympathomimetic agent of choice offering a 20-30% reduction in IOP.
• Carbachol->Inadequate response to or intolerance of pilocarpine-> patients frequently do well.
• S/E->Poor vision at night (due to pupil constriction), corneal clouding, burning (transient), hypotension, bronchospasm, abdominal cramps/GI distress.
• Use with caution in patients with a history of retinal detachment or corneal abrasion.

Approaching Pharmacoherapeutics

• Monotherapy: optimally started as a single agent. If medication monotherapy is insufficient to decrease IOP: consider combination therapy and switching medications.
• Good eye drop technique and adherence are Adequate treatment requirements.
• When drug therapy fails, is not tolerated, or proves too complicated, surgery may be the solution.

Key Concepts

• Reduction of IOP is essential to treat glaucoma.
• Prostaglandin analogs are considered the most potent topical medications for reducing IOP.
• Patient education and reinforcing adherence are essential to prevent glaucoma progression.