To investigate the potential association between gut microbiota and central serous chorioretinopathy (CSC), clinical observations have indicated that patients with CSC frequently present with chronic gastrointestinal symptoms. This observation has led to the hypothesis that CSC may be associated with gut dysbiosis.

The genus Bifidobacterium is widely recognized as a beneficial component of the gut microbiota, and multiple well-established Bifidobacterium supplements are commercially available. To explore this potential association, fecal samples will be collected from both CSC patients and healthy controls. Whole-metagenome shotgun sequencing will be performed to compare gut microbial compositions between the two groups and to determine whether significant differences exist.

In addition, CSC patients will be randomly assigned to two groups. One group will receive Bifidobacterium supplementation for a minimum of one month, while the other group will receive a placebo. Clinical outcomes will then be evaluated to assess whether Bifidobacterium supplementation is associated with faster recovery and reduced relapse rates compared with placebo.

Inclusion Criteria:

• Age 18 to 60 years
• Diagnosis of acute central serous chorioretinopathy (CSC) (affected eye: ① FFA and ICGA showing typical CSC manifestations, ② presence of subretinal fluid (SRF) at the macular fovea, ③ disease duration ≤ 6 months)
• Best Corrected Visual Acuity (BCVA): 53 to 86 letters
• Other: No significant systemic diseases, signed informed consent, and able to commit to follow-up

Exclusion Criteria:

• Presence of significant systemic diseases
• BCVA of 20/200 or worse
• Presence of choroidal or retinal atrophy in the macular fovea of the affected eye
• Presence of choroidal neovascularization (CNV), age-related macular degeneration (AMD), polypoidal choroidal vasculopathy (PCV), diabetic retinopathy (DR), choroidal hemangioma, pigment epithelial detachment (PED), etc., in the affected eye
• High myopia in the affected eye