What are the treatment options for glaucoma?

Treatment Options for Glaucoma

Prostaglandin analogs should be used as first-line therapy for glaucoma due to their superior efficacy, once-daily dosing, and favorable side effect profile. 1

First-Line Medical Therapy

Prostaglandin analogs are the preferred initial treatment for glaucoma for several key reasons:

• Most efficacious at lowering intraocular pressure (IOP)
• Well-tolerated by most patients
• Convenient once-daily dosing regimen
• Relatively safe side effect profile

The goal of treatment is to maintain IOP in a range that prevents visual field loss from affecting quality of life. For most patients, a target of 20% reduction from baseline IOP is reasonable, though this may need to be more aggressive in cases of advanced disease or high baseline IOP. 1

Treatment Algorithm

1. Start with prostaglandin analog (e.g., latanoprost)

   • If target IOP achieved → continue and monitor
   • If inadequate response → either switch to different medication or add second agent

2. Second-line options (if prostaglandin analog is ineffective or contraindicated):

   • Beta-adrenergic antagonists (e.g., timolol)
     • Caution: Avoid in patients with asthma, COPD, bradycardia, heart block 2
     • Note: Avoid nighttime dosing due to reduced efficacy and potential systemic effects
   • Alpha-2 adrenergic agonists (e.g., brimonidine)
   • Topical carbonic anhydrase inhibitors (e.g., dorzolamide, brinzolamide)
   • Rho kinase inhibitors (e.g., netarsudil)

3. Combination therapy (when monotherapy is insufficient):

   • Fixed-combination medications (e.g., prostaglandin-timolol combinations)
     • Advantages: Improved compliance, reduced preservative exposure, convenience 3, 4
     • Note: May be slightly less effective than unfixed combinations but better tolerated

Medication Efficacy Comparison

Drug Class	IOP Reduction	Key Advantages	Key Disadvantages
Prostaglandin analogs	25-35%	Once daily dosing, most effective	Conjunctival hyperemia, iris color change
Beta-blockers	20-25%	Well-established efficacy	Systemic side effects (bronchospasm, bradycardia)
Alpha-2 agonists	20-25%	Neuroprotective potential	Allergic reactions, fatigue
Carbonic anhydrase inhibitors (topical)	15-20%	Minimal systemic effects	Less effective than other classes
Carbonic anhydrase inhibitors (oral)	20-30%	Effective	Significant systemic side effects
Rho kinase inhibitors	10-20%	Novel mechanism	Conjunctival hyperemia

Special Considerations

• Angle-closure glaucoma: Requires different approach - immediate intervention to reopen the angle is the primary objective. Beta-blockers like timolol should not be used alone in angle-closure glaucoma. 2

• Renal impairment: Avoid dorzolamide in severe renal impairment (CrCl < 30 mL/min) 5

• Respiratory conditions: Avoid non-selective beta-blockers in patients with asthma or COPD; consider cardioselective beta-blockers with caution 1

• Pregnancy: Consider risk/benefit profile - most glaucoma medications are pregnancy category C 1

Common Pitfalls to Avoid

1. Inadequate target pressure: Failing to adjust target IOP based on disease progression or risk factors

2. Improper administration: Patients should avoid touching the tip of the bottle to the eye or surrounding structures to prevent contamination 5, 2

3. Washout effect: When using multiple medications, instill at least 5 minutes apart to prevent the second drop from washing out the first

4. Overreliance on monocular trials: Recent evidence suggests monocular trials may not reliably predict long-term efficacy 1

5. Neglecting adherence issues: Complex regimens reduce compliance; fixed combinations may improve adherence 4

The ultimate goal of glaucoma treatment is to preserve visual function and quality of life by preventing progressive optic nerve damage through effective IOP control. Regular monitoring of IOP, optic nerve structure, and visual fields is essential to evaluate treatment efficacy and disease progression.