Purpose To investigate whether the combined subconjunctival injection of dexamethasone can accelerate the decrease in intraocular pressure (IOP) in acute primary angle closure (APAC)-affected eyes.

Methods 42 patients with APAC were recruited for a randomised controlled trial. These patients were separated into two groups: the injection group (21 patients) and the control group (21 patients). The injection group was subjected to a subconjunctival injection with 2.5 mg dexamethasone. Other drug treatments were the same with the control group. The follow-up was at 0, 3, 6, 12 and 24 hours after injection. The outcome measures include IOP and intraocular inflammation variables.

Results The IOP was significantly decreased in both groups after treatment. However, 24 hours after the initial treatment, the IOP of the injection group was significantly lower compared with the control group (p = 0.017). Kaplan-Meier survival curve analysis showed that the total success rate of the injection group and the control group were 79.7% and 54.9% at 24 hours after treatment (p = 0.027), respectively. For the comparison of anterior chamber inflammation, the severity of conjunctival erythema, ciliary flush and pain in the injection group was also lower than that in the control group at 24 hours after treatment(p = 0.012, p = 0.048 and p = 0.013, respectively). No statistical significance was found between the two groups regarding the anterior chamber cells, anterior chamber flare and photophobia.

Conclusion The combined subconjunctival injection of dexamethasone for the management of APAC eyes can significantly accelerate the relief of high IOP, and therefore, improve the success rate of treatment.