Comparison of allergy prevalence using brinzolamide 1.0% / brimonidine 0.2% fixed combination with and without β-blocker in glaucoma patients: a retrospective cohort study.

Background: Glaucoma treatment often involves multi-drug regimens, which can lead to poor adherence and side effects. Fixed-dose combinations aim to improve adherence and reduce side effects compared to traditional therapies. This study aimed to compare the prevalence and clinical characteristics of ocular allergy in glaucoma patients using brinzolamide 1.0%/brimonidine 0.2% fixed combination (BBFC), with and without concurrent β-blocker.

Methods: Of these, 176 patients used a β-blocker concurrently, whereas 96 patients did not. Allergy prevalence, allergy type, and allergy occurrence time were compared between the concurrent and non-concurrent β-blocker-usage groups. Ocular allergies were classified and evaluated using Kaplan-Meier survival analysis.

Results: Allergy prevalence was 10.23% and 15.63% (p = 0.193), whereas allergy occurrence time was 15.92 ± 13.80 months and 6.26 ± 6.20 months (p = 0.04) in the concurrent and non-concurrent β-blocker-usage groups, respectively. Kaplan-Meier survival analysis indicated that half of the allergies in the concurrent β-blocker-usage group occurred within 12.5 months, with the BBFC discontinuation rate gradually increasing up to 36 months. Contrarily, half of the allergies in the non-concurrent β-blocker-usage group occurred within 3.3 months, with a rapid increase in BBFC discontinuation rate the first 6 months. Intergroup differences in allergy types were significant (p = 0.015). Among all patients with allergy, the average allergy occurrence time of blepharoconjunctivitis, papillary conjunctivitis, and follicular conjunctivitis was 12.52, 9.53, and 13.23 months, respectively. Follicular conjunctivitis tended to occur later than papillary conjunctivitis (p = 0.042). In the concurrent β-blocker-usage group, follicular conjunctivitis was the most prevalent allergy type (61.1%), whereas papillary conjunctivitis was the most common (66.7%) in in the non-concurrent β-blocker-usage group.

Conclusions: Concurrent use of β-blocker with BBFC decreases allergy prevalence, delays allergy onset, and predominantly results in follicular conjunctivitis, thereby facilitating longer treatment duration. Understanding these characteristics of allergy in BBFC users is useful to manage patients and improve treatment adherence. This study provides insights into the role of β-blockers in modulating ocular allergy in BBFC-treated glaucoma patients, highlighting implications for clinical practice and patient education.