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# Vitamin D Status, Intraocular Pressure, and Neuroinflammation Glaucoma is a chronic **optic neuropathy** leading to irreversible vision loss ([pmc.ncbi.nlm.nih.gov](https://pmc.ncbi.nlm.nih.gov/articles/PMC5156616/#:~:text=Glaucoma%20is%20a%20chronic%20progressive,Many)). Elevated **intraocular pressure (IOP)** is the main modifiable risk factor, but glaucoma is multifactorial, involving optic nerve damage, blood flow, and **neuroinflammation**. Vitamin D (measured as serum 25-hydroxyvitamin D) plays roles in bone metabolism, cell regulation, and immune signaling ([pmc.ncbi.nlm.nih.gov](https://pmc.ncbi.nlm.nih.gov/articles/PMC5156616/#:~:text=Recently%2C%20vitamin%20D%20has%20become,have%20indicated%20that%20vitamin%20D)). Experimental data suggest vitamin D is **neuroprotective**; low levels are linked to neurodegeneration ([pmc.ncbi.nlm.nih.gov](https://pmc.ncbi.nlm.nih.gov/articles/PMC5156616/#:~:text=25,have%20indicated%20that%20vitamin%20D)). Since deficiency is common, researchers have studied whether vitamin D status influences IOP, optic nerve health, or inflammation in glaucoma. We review human and animal studies, and also examine evidence linking vitamin D to lifespan and mortality. We also discuss how sun exposure, skin pigmentation, and health conditions confound vitamin D measurements, define deficiency thresholds, and summarize supplementation advice. ## Vitamin D and Glaucoma: IOP and Optic Nerve ### Observational and Case-Control Studies Several large surveys have tested if vitamin D levels correlate with glaucoma. For example, a Korean health-screening study of over 120,000 adults found **no overall difference** in glaucoma prevalence across vitamin D quintiles. However, women in the fourth quintile (moderately high 25(OH)D) had a **significantly lower** glaucoma risk than women in the lowest quintile (OR ≈0.71) ([pmc.ncbi.nlm.nih.gov](https://pmc.ncbi.nlm.nih.gov/articles/PMC5156616/#:~:text=females%29.%20According%20to%20the%20multivariable,979)). Another Korean analysis of national survey data found a striking *“reverse J-shaped”* association: people in the lowest vitamin D quintile had a much higher risk of open-angle glaucoma than those with moderate levels ([pmc.ncbi.nlm.nih.gov](https://pmc.ncbi.nlm.nih.gov/articles/PMC10282225/#:~:text=There%20was%20a%20reverse%20J,knowledge%2C%20the%20present%20study%20is)). In essence, very low vitamin D was linked to higher glaucoma prevalence. Smaller case-control studies echo this general trend. Investigations in France, Croatia, the U.S., and Turkey reported that glaucoma patients often have **lower serum vitamin D** than similarly-aged control subjects ([pmc.ncbi.nlm.nih.gov](https://pmc.ncbi.nlm.nih.gov/articles/PMC9032397/#:~:text=A%20leading%20cause%20of%20irreversible,have%20demonstrated%20that%20glaucoma)). (Not all were significant; one Turkish study found no difference ([pmc.ncbi.nlm.nih.gov](https://pmc.ncbi.nlm.nih.gov/articles/PMC9032397/#:~:text=,sample%20

Vitamin D Status, Intraocular Pressure, and Neuroinflammation

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