This audio article is from VisualFieldTest.com.
Read the full article here: https://visualfieldtest.com/en/uric-acid-antioxidant-versus-pro-oxidant-in-glaucoma
Test your visual field online: https://visualfieldtest.com
Support the show so new episodes keep coming: https://www.buzzsprout.com/2563091/support
Excerpt:
Uric Acid: Antioxidant Versus Pro-oxidant in GlaucomaIntroduction: Glaucoma is a progressive optic nerve disease in which oxidative stress and vascular dysfunction are thought to contribute to retinal ganglion cell loss. Uric acid (UA), the end product of purine metabolism, is of growing interest because it circulates at high levels in humans and has complex redox effects. In blood, UA is a potent antioxidant (scavenging radicals in plasma) (). However, inside cells or as crystals, UA can promote inflammation and oxidative stress. Recent studies on glaucoma have reported conflicting findings: some suggest higher serum UA correlates with worse glaucoma, whereas others suggest the opposite. We review these data, and explore how UA interrelates with autonomic (heart rate variability), endothelial, and kidney factors. We also consider common gout medications (which lower UA) and their potential eye effects. Personalized analyses by sex, kidney health, and metabolic status are warranted. Finally, we outline simple urine/blood tests (e.g. serum UA and kidney panels) a person can obtain and interpret to gauge risk factors.Uric Acid and Glaucoma: Conflicting Clinical EvidenceStudies of serum UA in glaucoma patients have yielded mixed results. A 2023 systematic review and meta-analysis (1,221 glaucoma patients vs. 1,342 controls) found that mean serum UA was slightly higher in glaucoma cases by about 0.13 mg/dL – not statistically significant (). In that review, three of six studies actually found lower UA in glaucoma patients (suggesting a protective antioxidant role), while three found higher UA in glaucoma (suggesting UA as a risk marker) (). For example, one report in primary open-angle glaucoma (POAG) noted significantly lower UA levels in patients than in controls, with the lowest UA in those with the most severe visual field loss (). That study even showed the UA–glaucoma trend was strongest in men (). In contrast, other studies found higher UA in glaucoma. Elisaf et al. reported that POAG subjects (without diabetes) had higher UA (≈6.2 mg/dL) than age-matched non-glaucoma controls (≈5.0 mg/dL, P=0.006) (). Another study found normal-tension glaucoma (NTG) patients had higher UA than controls (5.8 vs. 4.9 mg/dL) (). These discrepancies may relate to glaucoma subtypes (e.g. NTG vs. angle-closure) or population differences. For instance, several Chinese cohorts found lower UA in acute angle-closure glaucoma and slower glaucoma progression in those with higher UA () (). In summary, some data suggest a protective role (lower UA in worse glaucoma) (), while others imply UA is a risk factor (higher UA in glaucoma cases) () (). This mirror-opposite pattern underlies the “antioxidant vs. pro-oxidant” paradox. Because human studies differ by design, glaucoma definition, and populations, consensus is lacking. Physicians and patients should note that evidence is inconclusive: UA could reflect either inadequate antioxidant defense (if low) or systemic metabolic stress (if high). Biochemistry of Uric Acid: Antioxidant vs. Pro-oxidantBiochemically, UA has a classic dual nature. In the blood, urate is actually one of the major antioxidants. For example, it can scavenge singlet oxygen, peroxyl and hydroxyl radicals (). Evolutionarily, humans lost the enzyme uricase so t
