Glaucoma Treatment Options
Prostaglandin analogs are the first-line medical therapy for glaucoma due to their superior efficacy in lowering intraocular pressure (IOP), excellent tolerability, and once-daily dosing regimen. 1
Medical Therapy Options
First-Line Treatment
- Prostaglandin analogs (PGAs): Most effective at lowering IOP with 6-8 mmHg reductions from baseline 2
- Examples: Latanoprost, Travoprost, Bimatoprost
- Benefits: Once-daily dosing, minimal systemic side effects
- Side effects: Conjunctival hyperemia, eyelash growth, iris pigmentation changes
Second-Line/Add-on Treatments
When target IOP is not achieved with a single medication, additional options include:
Beta-adrenergic antagonists (Beta-blockers)
- Examples: Timolol, Betaxolol
- Mechanism: Decrease aqueous humor production
- Caution: Contraindicated in patients with asthma, COPD, bradycardia, heart block 3
Alpha-2 adrenergic agonists
- Examples: Brimonidine, Apraclonidine
- Mechanism: Decrease aqueous humor production and increase uveoscleral outflow
Carbonic anhydrase inhibitors
- Examples: Dorzolamide, Brinzolamide (topical); Acetazolamide (oral)
- Mechanism: Decrease aqueous humor production
- Caution: Not recommended in patients with severe renal impairment 3
Parasympathomimetics (Miotics)
- Example: Pilocarpine
- Mechanism: Increase conventional outflow
Target Intraocular Pressure
The goal of treatment is to maintain IOP at a level that prevents visual field loss affecting quality of life. A reasonable initial target is a 20-25% reduction from baseline IOP 4, 1. For patients with more severe disease or rapid progression, a more aggressive target may be necessary.
Laser Therapy
Laser trabeculoplasty is as effective as medical treatment as a first-line therapy for controlling IOP in open-angle glaucoma 4:
- Selective Laser Trabeculoplasty (SLT)
- Argon Laser Trabeculoplasty (ALT)
Both SLT and ALT have similar IOP-lowering efficacy, but SLT may be repeatable due to less tissue damage 4.
Surgical Options
When medical and laser therapies fail to adequately control IOP:
- Trabeculectomy: Most common glaucoma surgery, creates an alternative pathway for aqueous humor outflow
- Glaucoma Drainage Devices: Tube shunts to drain aqueous humor
- Minimally Invasive Glaucoma Surgery (MIGS): Newer procedures with faster recovery and fewer complications
Combination Therapy
If monotherapy fails to achieve target IOP, either switching medications or adding a second medication from a different class is appropriate 4. Fixed-combination products (two medications in one bottle) may improve adherence by:
- Reducing the number of drops needed
- Decreasing exposure to preservatives
- Avoiding the washout effect of sequential drop instillation 5, 6
Treatment Algorithm
- Initial Assessment: Determine severity of glaucoma damage and risk factors
- First-Line: Start with a prostaglandin analog once daily 4, 1
- Evaluate Response: If target IOP not achieved after 4-6 weeks:
- Option A: Add a second medication (beta-blocker, alpha-2 agonist, or carbonic anhydrase inhibitor)
- Option B: Consider laser trabeculoplasty
- Continued Management: If target IOP still not achieved:
- Add a third medication from a different class
- Consider fixed combinations to improve adherence
- Evaluate for surgical intervention
Common Pitfalls to Avoid
- Inadequate monitoring: Regular assessment of IOP and optic nerve status is essential
- Poor adherence: Fixed combinations and once-daily dosing can improve compliance
- Improper administration: Patients should be instructed on correct eye drop technique
- Systemic side effects: Beta-blockers can cause respiratory problems in susceptible patients
- Using beta-blockers at night: Can reduce efficacy and contribute to nocturnal hypotension 1
Glaucoma management requires ongoing monitoring of IOP, optic nerve structure, and visual field function to ensure that treatment is effectively preventing disease progression and preserving vision.