Which eye drops are safe for treating allergic conjunctivitis in a patient with open‑angle glaucoma?

Safe Eye Drops for Allergic Conjunctivitis in Open-Angle Glaucoma

Dual-action antihistamine/mast cell stabilizers—specifically olopatadine, ketotifen, epinastine, or azelastine—are safe and recommended as first-line therapy for allergic conjunctivitis in patients with open-angle glaucoma. 1

First-Line Pharmacologic Treatment

• Dual-action topical agents (olopatadine, ketotifen, epinastine, azelastine) are the preferred initial therapy because they provide rapid symptom relief, prevent future episodes, and have no effect on intraocular pressure (IOP). 1

• These agents combine antihistamine and mast cell stabilizing properties, offering both immediate relief and ongoing protection with twice-daily dosing. 1

• Storing these drops in the refrigerator provides additional cooling relief upon instillation. 1

Safe Adjunctive Measures

• Refrigerated preservative-free artificial tears 4 times daily help dilute allergens and inflammatory mediators without affecting IOP. 1

• Cold compresses provide immediate symptomatic relief and reduce inflammation. 1

• Sunglasses act as a physical barrier against airborne allergens. 1

• Strict avoidance of eye rubbing is crucial, as it can worsen symptoms and potentially lead to keratoconus, especially in atopic patients. 1

Second-Line Options When First-Line Therapy Is Insufficient

• Mast cell stabilizers alone (cromolyn, lodoxamide, nedocromil, pemirolast) are safe for prophylactic use but require several days to achieve optimal relief. 1

• Topical NSAIDs such as ketorolac provide temporary relief of ocular itching and are safe in glaucoma patients. 1

Critical Medications to AVOID

• Never use topical corticosteroids as routine therapy in glaucoma patients due to the risk of steroid-induced IOP elevation and cataract formation. 1

• If corticosteroids are absolutely necessary for severe symptoms unresponsive to dual-action agents after 48 hours, use only loteprednol etabonate (the lowest side-effect profile steroid) for a maximum of 1-2 weeks. 1

• Mandatory monitoring when using any corticosteroid includes baseline and periodic IOP measurement plus pupillary dilation to evaluate for glaucoma progression and cataract. 1

• Avoid chronic use of over-the-counter antihistamine/vasoconstrictor combinations (naphazoline/pheniramine) as prolonged vasoconstrictor use causes rebound hyperemia. 1

• Avoid oral antihistamines as primary treatment because they may worsen dry eye syndrome and impair the tear film's protective barrier. 1

• Never use punctal plugs in allergic conjunctivitis as they prevent flushing of allergens and inflammatory mediators from the ocular surface. 1

Severe or Refractory Cases

• For vernal or atopic keratoconjunctivitis unresponsive to dual-action agents, topical cyclosporine 0.05% at least 4 times daily or tacrolimus can be used as steroid-sparing immunomodulators. 1

• Cyclosporine 0.1% is FDA-approved for vernal keratoconjunctivitis in both children and adults. 1

• These immunomodulatory agents allow for reduced corticosteroid use while maintaining disease control. 1

Clinical Algorithm for Glaucoma Patients

1. Start with dual-action antihistamine/mast cell stabilizer (olopatadine, ketotifen, epinastine, or azelastine) twice daily plus refrigerated preservative-free artificial tears 4 times daily. 1

2. If symptoms persist after 48 hours, consider adding topical ketorolac or switching to a different dual-action agent before considering steroids. 1

3. Only if severe symptoms remain inadequately controlled, add loteprednol etabonate for 1-2 weeks maximum with mandatory IOP monitoring at baseline, 1 week, and 2 weeks. 1

4. For chronic severe disease, transition to topical cyclosporine 0.05% or tacrolimus as a steroid-sparing alternative. 1

Common Pitfalls to Avoid

• The most critical error is using topical corticosteroids without close IOP monitoring in glaucoma patients, as steroid-induced IOP elevation can occur rapidly and worsen pre-existing glaucoma. 1

• Failing to recognize that oral antihistamines may actually exacerbate allergic conjunctivitis by worsening dry eye syndrome. 1

• Using combination antibiotic-steroid drops (e.g., Tobradex) for allergic conjunctivitis, which provides no benefit for allergic disease and unnecessarily exposes the patient to steroid-related IOP elevation. 2