Evaluation of the Effect of Garlic Tablet as a Complementary Treatment for Patients with Diabetic Retinopathy

PURPOSE: The aim of this study was to investigate the effectiveness of garlic (Allium sativum L.) tablets as a complimentary herbal medication in diabetic macular edema. METHODS: A total of 91 diabetic participants (117 eyes) with central involved macular edema underwent a double-blind randomized trial. The patients used garlic tablets (500 mg) (2 tab/day) or placebo for 4 weeks and subsequently were examined by an expert ophthalmologist. Clinical manifestations including the best-corrected visual acuity (BCVA, logMAR), central macular thickness (CMT, μm), and intraocular pressure (IOP) were measured as the main outcomes. RESULTS: BCVA was significantly improved by a 0.18 decrease in mean logMAR value in the garlic-treated patients in comparison with 0.06 in the control ones (P value = 0.027). CMT was decreased in both groups by a 102.99 μm decrease in the garlic group compared to 52.67 μm in the placebo group, albeit in a nonsignificant manner (P value: 0.094). IOP was decreased in the garlic group by 1.03 mmHg (P value: 0.024) and increased by 0.3 mmHg (P value: 0.468) in the placebo group. CONCLUSION: Our trial suggests that garlic supplements can improve visual acuity, decrease the CMT and lower the IOP, and can be considered as an adjuvant treatment in patients with diabetic macular edema. Garlic was satisfactorily tolerated in diabetic patients, and no significant adverse effect interrupting the safety profile was observed.