EFFECT OF ANTIOXIDANT SUPPLEMENTATION ON OXIDATIVE STRESS AND RETINAL NEURODEGENERATION BIOMARKERS IN PATIENTS WITH PRIMARY OPEN-ANGLE GLAUCOMA: A RANDOMIZED CONTROLLED TRIAL

Abstract

Background:

Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness, characterized by progressive retinal ganglion cell loss despite adequate intraocular pressure (IOP) control. Increasing evidence suggests that oxidative stress contributes to retinal neurodegeneration in glaucoma. Antioxidant supplementation may provide a neuroprotective approach by reducing oxidative damage and preserving retinal structures.

Objective:

To evaluate the effect of oral antioxidant supplementation on oxidative stress biomarkers and retinal neurodegeneration parameters in patients with primary open-angle glaucoma.

Methods:

This prospective, open-label randomized controlled trial was conducted over six months at the Department of Ophthalmology, Services Hospital Lahore. Forty patients with mild to moderate primary open-angle glaucoma (POAG) were randomly allocated to an antioxidant supplementation group (n=20) or a control group (n=20). The intervention group received oral antioxidants in addition to standard glaucoma treatment, while the control group received standard glaucoma treatment alone. Oxidative stress biomarkers (MDA, TAC, SOD, and GPx) and retinal structural parameters (RNFL and GCC thickness) were assessed at baseline and six months. Statistical significance was set at p<0.05.

Results:

All 40 participants completed the six-month follow-up. Baseline demographic, clinical, and glaucoma treatment characteristics were comparable between groups. The antioxidant group demonstrated a significant reduction in MDA levels (4.82 ± 0.72 to 3.71 ± 0.61 nmol/mL, p<0.001) with increased TAC, SOD, and GPx levels (all p<0.001). RNFL and GCC thickness remained stable in the antioxidant group, whereas the control group showed significant thinning of both parameters (p<0.001). No significant changes were observed in BCVA or IOP between groups. Pearson correlation analysis showed a negative correlation between MDA and RNFL thickness (r=-0.52, p=0.001), while TAC, SOD, and GPx showed positive correlations with retinal structural parameters.

Conclusion:

Antioxidant supplementation improved oxidative stress status and enhanced antioxidant defense mechanisms in patients with POAG. Preservation of RNFL and GCC thickness suggests a potential neuroprotective effect through reduction of oxidative stress-related retinal damage. These findings support antioxidant supplementation as a potential adjunctive strategy in glaucoma management, although further long-term studies with larger populations are required to evaluate its effect on disease progression.

Keywords: Primary open-angle glaucoma, oxidative stress, antioxidants, retinal nerve fiber layer, ganglion cell complex