Purpose To evaluate the efficacy of oral spironolactone in patients with acute central serous chorioretinopathy (CSC).

Methods This is a prospective, randomised controlled clinical study. Thirty patients with acute CSC were the participants, including 18 patients who were treated with spironolactone (40 mg orally, twice daily) for 2 months in the experimental group and 12 patients who received observation in the control group. Main outcome measures included the proportion of eyes achieving complete resolution of subretinal fluid (SRF), changes in central macular thickness (CMT), the height of SRF (SRFH), best corrected visual acuity (BCVA) and subfoveal choroidal thickness (SFCT). The follow-up period was 2 months.

Results Complete resolution of SRF was achieved in 55.6% (10/18) and 8.3% (1/12) of the eyes in the treatment group and the control group, respectively, at 2 months (p=0.018). The mean CMT and SRFH decreased significantly at each visit in both groups (p<0.05), and there was significant difference between the two groups at 2 months (p<0.05 and p<0.05, respectively). BCVA (in logarithm of the minimum angle of resolution; mean) improved in both groups at 2 months (p<0.05). In the treatment group, the mean baseline SFCT significantly decreased from 502.50±87.38 µm to 427.44±74.37 µm at 2 months (p<0.01), while the change from baseline (from 480.33±102.38 µm to 463.75±100.63 µm) was not significant in the control group (p=0.195). But the differences between the two groups in BCVA and SFCT were not significant.

Conclusions Oral spironolactone is more effective with a faster absorption of SRF than observations. It is a promising treatment for acute CSC.

Trial registration number ChiCTR-IPR-16008428, Results.