This project is designed to evaluating the use of combination therapy of glucocorticoid and metformin to decrease glucocorticoid side effects in participants with autoimmune uveitis.This study also aims to evaluate the anti-inflammatory and immunosuppressive effects of combination therapy.

Approval of the study was obtained from the hospital's ethical committee. The study design and methodology followed the tenets of Declaration of Helsinki. All participants were provided with written informed consent and received a thorough explanation of the study design, aims, and the side effect of metformin. This is a multicenter, randomized, controlled clinical trial research. According to 1:1 ratio, all participants are randomly divided into two groups, the metformin group and placebo group.

According to the fasting blood glucose (FBG), triglycerides (TG),total cholesterol (TC) and body mass index (BMI), the investigators compared experimental group with control group to evaluate whether the use of combination therapy of glucocorticoid and metformin decrease glucocorticoid side effects in participants with autoimmune uveitis.

According to best corrected visual acuity (BCVA), anterior chamber and vitreous inflammation, fluorescence fundus angiography (FFA), electroretinogram (ERG) and so on, the investigators evaluate the anti-inflammatory and immunosuppressive effects of metformin in treatment of autoimmune uveitis.

Inclusion Criteria:

1. Attending Tianjin Medical University Eye Hospital, ophthalmology department of Peking Union Medical College Hospital, ophthalmology department of Peking University First Hospital and Zhongshan Ophthalmic Center Sun Yat-sen University from January 2018 to January 2022.
2. Chronic and non-infectious autoimmune uveitis with systemic glucocorticoids treatment (Initiation dosage ≥ 1 mg/kg/d or ≥ 50 mg/d).
3. FBG < 6.1 mmol/L, HbAlc<6.O%, TC <6.2 mmol/L(240 mg／d1) and TG <2.3 mmol/L(200 mg／dl).
4. All genders, age ≥ 18 years old.
5. Ready for systemic glucocorticoids treatment.
6. Willing to follow all study requirements and sign the informed consent.
7. Without history of cancer and serious systemic diseases.

Exclusion Criteria:

1. Participate in other clinical trials within the preceding one years
2. Planning ophthalmologic surgery over the next three months.
3. With other sight-threatening diseases except cataract, such as glaucoma, diabetic retinopathy, retinal detachment, and so on.
4. Taking or will take immunosuppressants which affecting glycometabolism and lipid metabolism except methotrexate,mycophenolate and azathioprine.
5. Any known history of a serious infection (e.g., HIV, hepatitis, pneumonia, syphilis or tuberculosis).
6. Any known history of diabetes mellitus, severe hepatic, renal or heart disease.
7. Any known history of drug addiction, drug abuse and malignant tumor.
8. Presence of a transplanted solid organ.
9. Pregnant women and nursing mothers.
10. Any known history of mental disorders.

The study protocol,statistical analysis plan,informed consent form and clinical study report are to be shared with other researchers.

The data will become available starting 6 months after publication.

The study protocol,statistical analysis plan,informed consent form and clinical study report are to be shared with other researchers.