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Excerpt:

IntroductionGlaucoma is an eye disease in which retinal ganglion cells (RGCs) – the nerve cells that carry visual signals from the eye to the brain – slowly die. This causes gradual, irreversible vision loss. Doctors usually focus on lowering eye pressure to slow glaucoma, but research now shows that oxidative stress (a kind of chemical stress in the body) and imbalances in the autonomic nervous system (the “automatic” nervous system that controls things like heart rate) also play a role. In glaucoma patients, blood levels of certain redox markers – substances that indicate oxidative damage – tend to be higher than normal. At the same time, many glaucoma patients have depressed heart rate variability (HRV), a sign of autonomic imbalance. Together, raised oxidative stress and poor autonomic regulation may worsen RGC damage. In this article, we explain what oxidative stress markers like F2-isoprostanes, malondialdehyde (MDA), and 8-hydroxy-2’-deoxyguanosine (8-OHdG) are, and how they are found in glaucoma. We define HRV (heart rate variability) and review how it is altered in glaucoma. We describe possible biological pathways linking oxidative stress and autonomic imbalance to faster RGC death. We then summarize what studies of antioxidants (nutrients that fight oxidative stress) have shown on glaucoma outcomes. Finally, we suggest future “multi-omics” studies that combine blood or urine redox markers, HRV measurements, and advanced retinal imaging for new insights.Throughout, we focus on information that patients can understand and act on. We also explain which oxidative stress tests can be ordered (via blood or urine) and what high or low readings might mean for someone concerned about glaucoma.Oxidative Stress Markers in GlaucomaOxidative stress means there are too many “free radicals” (reactive oxygen molecules) in the body, causing damage to cells. We cannot directly measure free radicals easily, so doctors and researchers use biomarkers in blood or urine that indicate oxidative damage. Three important markers in glaucoma are F2-isoprostanes, malondialdehyde (MDA), and 8-hydroxy-2’-deoxyguanosine (8-OHdG). All three rise when oxidative stress increases.F2-Isoprostanes (8-iso-PGF2α) – these are stable molecules formed when fats (polyunsaturated fats in cell membranes) oxidize. F2-isoprostanes are considered a “gold standard” for measuring lipid (fat) oxidation (). Higher blood or urine levels of these suggest that cells are under oxidative attack. Although not all glaucoma studies measure them, high F2-isoprostane levels have been found in many diseases and are thought to reflect strong oxidative stress (). (In practice, labs can measure F2-isoprostanes in urine or plasma using specialized equipment, but this is mostly done in research settings.) Malondialdehyde (MDA) – this chemical is produced when reactive oxygen species break down fats in the body. Like F2-isoprostanes, it signals fat damage from oxidation. Multiple glaucoma studies have found that glaucoma patients have higher MDA in their blood than healthy people () (). In fact, a large review found that MDA was the most consistently elevated oxidative stress marker in glaucoma patients’ blood (). In one study of angle-closure glaucoma, patients had significantly higher MDA than control subjects (). Notably, that study showed patients with very high MDA levels had faster vision loss: those with MDA above about 12 units had much more rapid visual field decline (). 8-Hydroxy-2’-deoxyguanosin