Oxidative Stress Modulation by Medicago Sativa Extract Slows Axial Elongation in High Myopia: A Randomized Controlled Trial

Abstract

High myopia is a leading cause of irreversible visual impairment worldwide, driven partly by oxidative stress-mediated axial elongation. Despite low-dose atropine (0.01%) being the current standard, its effect on oxidative imbalance remains limited. This study investigated whether adjuvant Medicago sativa L. extract (EMS) modulates malondialdehyde (MDA) and superoxide dismutase (SOD) levels and consequently slows axial elongation in high myopia. A double-blind randomized controlled trial enrolled 40 adolescents (aged 13-18 years) with high myopia (> -6.00 D) receiving atropine 0.01%. Participants were randomized to EMS 500 mg twice daily (n=20) or placebo (n=20) for six months. Plasma MDA and SOD were measured spectrophotometrically at baseline, month 3, and month 6. Axial length (AL) was measured using A-scan ultrasonography. EMS significantly reduced plasma MDA from 28.81 ± 6.85 to 17.16 ± 3.77 μmol/L (p<0.001) while the placebo group showed progressive increase (24.05 ± 6.00 to 29.96 ± 5.03 μmol/L; p<0.001). SOD increased markedly in the EMS group (0.99 ± 0.17 to 5.06 ± 1.94 mg/dL; p<0.001) versus a decline in the placebo group (0.87 ± 0.20 to 0.65 ± 0.29 mg/dL). The EMS group demonstrated significantly lower axial elongation over 6 months (OD: 0.05 ± 0.03 mm vs 0.45 ± 0.18 mm; OS: 0.06 ± 0.03 mm vs 0.49 ± 0.17 mm; both p<0.001). Changes in MDA and SOD did not directly correlate with axial length changes, suggesting indirect or locally mediated mechanisms. EMS as adjuvant therapy to atropine 0.01% significantly improves oxidative redox balance and attenuates axial elongation in high myopia. These findings support the therapeutic potential of antioxidant supplementation in myopia management.