Prophylactic effect of brimonidine to minimize the incidence of subconjunctival hemorrhage in the early postoperative period after 23G pars plana vitrectomy

BACKGROUND: Several studies have investigated and demonstrated the prophylactic effect of brimonidine drops in preventing subconjunctival hemorrhage in some microincisional ophthalmic surgeries, such as intravitreal injections or cataract surgery. However, there are no previous studies investigating this prophylactic effect after 23G microincisional vitreoretinal surgery. AIM: The aim of the current study was to determine whether subconjunctival hemorrhage after 23G pars plana vitrectomy (PPV) could be prevented with the use of prophylactic topical brimonidine. METHODS: This was a phase III, prospective, interventional, randomized, controlled single-center clinical trial with a follow-up of 2 weeks. A total of 77 eyes (mean age: 68.4 ± 10.7 years) undergoing 23G PPV were included and randomized into two groups: group 1 including 41 patients receiving prophylactic preoperative treatment with brimonidine, and group 2 (control group) including 36 patients not receiving this prophylactic treatment. Differences in terms of number of conjunctival quadrants affected with subconjunctival hemorrhage were evaluated in each of the follow-up visits. RESULTS: The presence of subconjunctival hemorrhage was similar in both groups the first days after surgery (p > 0.05). At the last visit (10–14 days after surgery), this condition was significantly more frequent in control group where there was a significant difference, being more frequent in the control group (7.3% vs 28.6%, p = 0.022). The number of conjunctival quadrants affected was also similar in both groups, except for the last visit in which most of the patients treated with brimonidine (92.7%) showed no bleeding compared to 71.4% in control group. No effect on the efficacy of brimonidine treatment of the presence of blood hypertension, diabetes, and antiplatelet or anticoagulant treatment was observed. CONCLUSION: Brimonidine seems to be a useful option to decrease subconjunctival hemorrhage after microincisional vitreoretinal surgery or improve its resolution during the first postoperative week. This finding should be mainly due to the vasoconstrictor effect of brimonidine. TRIAL REGISTRATION: EudraCT, 2012-002895-15 (registered 19 December 2012); https://www.clinicaltrialsregister.eu/ctr-search/search?query=2012-002895-15