For a patient with glaucoma in whom an intravitreal injection is being considered, which agent should be used and what is the dosing and follow‑up protocol?

Intravitreal Injections Are Not Standard Treatment for Glaucoma

Glaucoma is not treated with intravitreal injections as primary therapy. The standard treatment for primary open-angle glaucoma consists of topical medications (prostaglandin analogs as first-line), laser therapy, or incisional surgery—not intravitreal injections 1.

Standard Glaucoma Management

First-Line Medical Therapy

• Prostaglandin analogs are the preferred initial treatment because they are most efficacious, well-tolerated, and require only once-daily dosing 1
• Alternative topical agents include beta-blockers, alpha-2 adrenergic agonists, parasympathomimetics, and carbonic anhydrase inhibitors 1
• The goal is to lower IOP by at least 25% from baseline to slow progression 1

When Intravitreal Injections May Be Relevant

Neovascular glaucoma (NVG) is the only glaucoma subtype where intravitreal anti-VEGF agents have a role, and even then, they are adjunctive to standard retinal ablative procedures, not standalone treatment 2, 3.

For Neovascular Glaucoma Specifically:

• Bevacizumab 1.25 mg/0.05 mL intravitreally has been used as adjunctive therapy to cause rapid regression of anterior segment neovascularization 2, 3
• Typical protocol involves three injections at 4-week intervals 3
• Critical caveat: Central retinal artery occlusion occurred in 50% of patients with ocular ischemic syndrome who received anti-VEGF injections for NVG 2
• This treatment should only be considered after standard retinal ablative procedures (panretinal photocoagulation) have been performed 3

Important Safety Concerns

Anti-VEGF Injections Can Worsen Glaucoma

• Repeated intravitreal anti-VEGF injections can cause sustained IOP elevation requiring surgical intervention in some patients, even those without prior glaucoma history 4
• This appears more common with bevacizumab and products dispensed from broken bulk 4
• The mechanism may involve high molecular weight aggregates or silicone oil droplets causing trabecular meshwork inflammation 4

Proper Injection Technique (If Indicated)

If an intravitreal injection is deemed necessary for a retinal condition in a patient with glaucoma:

• Apply povidone-iodine 5% to the conjunctiva and allow 2-3 minutes for drying before injection 1, 5
• Use sterile lid speculum and topical anesthetic 1
• Inject 3.0-4.0 mm posterior to the limbus via pars plana 1
• Routine topical antibiotics are not required and may paradoxically increase endophthalmitis risk 1
• Confirm retinal artery perfusion after injection by checking gross visual acuity or direct fundus visualization 1

Clinical Algorithm

For primary open-angle glaucoma:

1. Start with topical prostaglandin analog 1
2. Add or switch to beta-blocker, alpha-agonist, or carbonic anhydrase inhibitor if target IOP not achieved 1
3. Consider laser trabeculoplasty or incisional surgery if medical therapy fails 1

For neovascular glaucoma:

1. Perform panretinal photocoagulation first 3
2. Consider adjunctive intravitreal bevacizumab only if anterior segment neovascularization persists 3
3. Avoid in patients with ocular ischemic syndrome due to 50% risk of central retinal artery occlusion 2
4. Monitor IOP closely long-term after any anti-VEGF injections 4

If a patient with glaucoma requires intravitreal injections for a separate retinal condition (diabetic macular edema, retinal vein occlusion):

• Document baseline IOP and optic nerve status 6
• Establish target IOP approximately 20% lower than baseline 6
• Follow-up every 4-8 weeks during first year with IOP monitoring 6
• Intensify topical IOP-lowering medications if elevation occurs 6