To compare the allergy prevalence and clinical manifestations of 0.2% brimonidine/0.5% timolol fixed combination (BTFC) and 0.15% brimonidine in Korean patients with glaucoma.

We retrospectively analyzed the medical records of 196 glaucoma patients treated with BTFC and 234 glaucoma patients treated with 0.15% brimonidine. We compared sex, age, type of glaucoma, treatment period, allergy history, onset time of ocular allergy and clinical characteristics of allergy in the two groups.

Ocular allergy percentages 10.14% in the BTFC group and 22.02% in the 0.15% brimonidine group, and the risk of allergy was approximately 0.4 times lower in patients using BTFC (hazard ratio = 2.5, p = 0.009). The BTFC group developed ocular allergy at a mean of 20.5 months (range: 1.7–51.1 months), and the 0.15% brimonidine group developed ocular allergy at a mean of 7.7 months (range: 0.4–50.8 months). In the BTFC group, 50% of the ocular allergy occurred within 15 months, and within 5 months in the 0.15% brimonidine group. Clinical characteristics of brimonidine allergy involved two types of conjunctival follicles and conjunctival papillae, but there were no significant differences in incidence according to allergy type ( p = 0.566).

The prevalence of ocular allergy in the BTFC group was lower than that in the 0.15% brimonidine group in Korean patients with glaucoma. The results of this study are expected to be useful for patient education and compliance improvement using brimonidine.