Glaucoma Treatment
Prostaglandin analogs (specifically latanoprost, bimatoprost, or travoprost) are the first-line treatment for glaucoma, but in patients with asthma or COPD, avoid beta-blockers entirely and use prostaglandin analogs as initial therapy, or consider alternative agents like alpha-2 agonists (brimonidine), topical carbonic anhydrase inhibitors (dorzolamide/brinzolamide), or rho kinase inhibitors (netarsudil). 1
First-Line Treatment: Prostaglandin Analogs
Prostaglandin analogs are the most efficacious and well-tolerated glaucoma medications, requiring only once-daily dosing, making them the preferred initial therapy unless contraindications exist 1
Bimatoprost achieves the greatest IOP reduction (5.61 mmHg), followed closely by latanoprost (4.85 mmHg) and travoprost (4.83 mmHg) at 3 months 2
Latanoprost reduces IOP by 6-8 mmHg in patients with baseline pressures of 24-25 mmHg, equivalent to timolol 0.5% twice daily 3, 4
The within-class differences between prostaglandin analogs are small and may not be clinically meaningful, so selection can be based on tolerability, cost, and patient preference 2
Latanoprost has the best efficacy-tolerability ratio among prostaglandin analogs, with significantly better tolerance than bimatoprost or travoprost 4
Critical Consideration: Asthma/COPD Patients
Nonselective beta-blockers (timolol) block both beta-1 and beta-2 receptors and are contraindicated in patients with obstructive airway disease 1
Cardioselective beta-blockers (betaxolol) minimize but do not completely eliminate pulmonary adverse effects 1
In patients with asthma or COPD, comorbidities must be considered when selecting topical ocular hypotensive agents 1
Alternative Agents When Prostaglandins Are Not Tolerated
If prostaglandin analogs cannot be used due to intolerance or contraindications:
Timolol 0.5% twice daily achieves IOP reductions of 7-9 mmHg and is the most effective beta-blocker, but only use in patients WITHOUT pulmonary disease 5
Alpha-2 agonists (brimonidine) reduce IOP by 3.59 mmHg and are effective second-line agents 2, 6
Topical carbonic anhydrase inhibitors (dorzolamide 2.49 mmHg, brinzolamide 2.42 mmHg) are safe alternatives with no pulmonary contraindications 1, 2
Rho kinase inhibitors (netarsudil) reduce IOP by 10-20% through increased trabecular outflow 1
Combination Therapy for Inadequate Response
If target IOP is not achieved with monotherapy, add a second medication from a different class rather than switching if the first medication showed any IOP response 1
Prostaglandin-timolol fixed combinations are more effective than either component alone as monotherapy, but only use in patients without pulmonary disease 1, 7
Alpha-2 agonist-prostaglandin and carbonic anhydrase inhibitor-prostaglandin combinations are at least as effective as beta-blocker-prostaglandin combinations 7
Fixed combinations simplify dosing, improve adherence, reduce preservative exposure, and prevent washout effects 7
Target IOP and Monitoring
Target IOP should be 20% lower than baseline mean IOP, though higher reductions (25% or more) slow progression of established glaucoma 1
Check IOP response within 2-4 weeks of initiating therapy to confirm adequate pressure reduction 5
Instruct patients to wait at least 5 minutes between different eye drops to prevent washout 5
Common Pitfalls to Avoid
Never dose beta-blockers at nighttime—this is associated with limited efficacy and may contribute to visual field progression via nocturnal reduction of systemic blood pressure 1
Do not use nonselective beta-blockers in patients with asthma, COPD, or other obstructive airway disease due to beta-2 receptor blockade 1
Remove contact lenses prior to administering latanoprost and wait 15 minutes before reinsertion 3
Monitor for iris pigmentation changes with prostaglandin analogs—this typically occurs within the first year and may be permanent 3
Use prostaglandin analogs with caution in patients with active intraocular inflammation (iritis/uveitis) or macular edema risk factors 3