An Innovative Chinese Herbal Formula for Macular Edema

Macular edema (ME) is caused by hyperpermeability of retinal vessels and/or decreased efflux of fluid across the retinal pigment epithelium induced by outer/inner blood-retinal barrier dysfunction (BRB). It is most commonly seen following many diseases such as diabetes mellitus (DM), intraocular surgery, uveitis, retinal vein occlusion, and posterior segment inflammatory disease. An estimated 11% of patients with DM develop diabetic macular edema (DME). While the overall prevalence of DME among patients with DM aged 20 to 79 years is approximately 7.5%, the risk increases over time. Currently, there is no cure for ME. Chinese medicine (CM) is widely used to manage ME in China and other East Asian countries. Among them, Shenling Baizhu San (SBS) is one of the most commonly used formulae. In this proposal, a randomized, double-blind, placebo-controlled, multicenter clinical trial will be undertaken to evaluate the efficacy and safety of modified SBS (mSBS) developed by the project team for the treatment of ME. Eligible subjects will be recruited and assigned randomly to receive orally mSBS or placebo twice a day for 12 consecutive weeks, with follow-up for another 4 weeks after stopping the treatment to observe the duration of efficacy.

Inclusion Criteria: * Both gender; * Age from 18 to 80 years; * Known diagnosed with ME; * Agree to under optical examination and willing to complete questionnaires and take medications as scheduled; and * Agree to participate in the study and provide written informed consent. (for those illiterate subjects, their family member can sign the consent form upon subject's agreement) Exclusion Criteria: * Known ocular media opacities, such as cataract, vitreous hemorrhage, asteroid hyalosis, that affect the determination of retinal thickness from OCT imaging; * Known clinically significant macular edema (CSME). The definition of CSME: if one or more of the following criteria are met 1) retinal thickening at or within 500 μm of the center of the macula; 2) hard exudates at or within 500 μm of the center of the macula, if associated with adjacent retinal thickening; 3) a zone or zones of retinal thickening one disc area in size, at least part of which is within one disc diameter of the center of the macula; * On concomitant oral or injectable corticosteroids, topical non-steroidal anti-inflammatory drugs (NSAID) eye drops, leukotriene inhibitors, anti-VEGF, immunosuppressants for the treatment of ME within past 6 months or other Chinese herbal medicine for the treatment of ME within past month; * Impaired hematological profile and liver / renal function exceeds the upper limit of the reference value by 2 times; * Documented pregnant or lactating; or * Subjects participating in other clinical studies at the same time.