Natural Support

Evidence-based nutritional and lifestyle support for glaucoma — vitamin B3 nicotinamide, ginkgo biloba, magnesium, bilberry/pine bark, omega-3, and the role of ocular blood flow and mitochondrial health alongside standard pressure-lowering treatment

Glaucoma quietly damages the optic nerve, usually starting at the edges of vision and creeping inward over years — and because the central vision stays sharp until late in the disease, most people don't notice anything wrong until significant damage has already happened. Around 76 million people worldwide have glaucoma, and the number is projected to reach nearly 112 million by 2040. [1] Lowering eye pressure with prescription drops or surgery is the standard treatment and remains the only intervention proven to slow vision loss — but a meaningful share of glaucoma progression happens despite controlled pressure, suggesting other factors like ocular blood flow, mitochondrial health, and oxidative stress also matter. [7] Several natural approaches — vitamin B3 (nicotinamide), ginkgo biloba, magnesium, and bilberry/pine bark extracts — have credible randomised evidence for protecting the optic nerve alongside conventional treatment. None of these replace pressure-lowering therapy.

Why Pressure Isn't the Whole Story

Glaucoma is an optic neuropathy — the retinal ganglion cells whose long axons form the optic nerve gradually die, taking visual field with them. Elevated intraocular pressure (IOP) is the single biggest risk factor and the only one we can pharmacologically control, which is why prostaglandin drops (latanoprost and similar) are first-line therapy worldwide. But two patterns reveal pressure is only part of the picture. First, in normal-tension glaucoma, the optic nerve degenerates despite IOP staying within the statistically "normal" range — these patients tend to have impaired ocular blood flow regulation, low blood pressure at night, migraines, cold extremities (Raynaud-like vascular dysregulation), and Flammer syndrome features. [7] Second, even with well-controlled IOP, around a third of patients continue to lose visual field over time. This points to mitochondrial dysfunction in retinal ganglion cells and oxidative stress as parallel drivers of damage that pressure-lowering doesn't fully address. [2][7]

This means there's room — alongside, never instead of, your prescribed drops — for interventions that target the other half of the disease.

Vitamin B3 (Nicotinamide) — the Strongest New Lead

In 2017, a landmark study in Science showed that aged glaucoma-prone mice given high-dose oral nicotinamide (vitamin B3) had dramatically less optic nerve damage than untreated mice. The effect was striking: at the highest dose, around 93% of eyes did not develop glaucoma. [2] The mechanism: nicotinamide is a precursor to NAD+, the cellular coenzyme that powers mitochondrial energy production. Retinal NAD+ levels decline with age, leaving optic nerve cells vulnerable to pressure-induced metabolic stress. Restoring NAD+ keeps the mitochondria — and the cells — alive.

This led directly to a human trial. Hui et al. (2020) ran a crossover randomised trial in 57 glaucoma patients already on standard pressure-lowering treatment, giving them 6 weeks of 1.5 g/day then 6 weeks of 3.0 g/day nicotinamide versus placebo. After nicotinamide, electrical response of the inner retina (PhNR amplitude — a measure of retinal ganglion cell function) improved beyond the 95% coefficient of repeatability in 23% of participants vs 9% on placebo. Mean improvement was 14.8% on nicotinamide vs 5.2% on placebo. [3] This is a small trial measuring a surrogate endpoint, not visual-field preservation over years, but it's the first human evidence that the mouse mechanism translates.

Practical doses studied are well above the daily nutritional requirement (~16 mg). The 2020 trial used 1.5–3 g/day of nicotinamide (the amide form, not niacin/nicotinic acid which causes flushing and has different effects). At these doses, monitoring liver function periodically is reasonable, and people on chemotherapy or with liver disease should consult their physician. The American Glaucoma Society in 2025 took the position that there is now enough evidence for ophthalmologists to discuss nicotinamide with glaucoma patients as adjunctive therapy.

Ginkgo Biloba — for Normal-Tension Glaucoma in Particular

Ginkgo biloba extract improves ocular blood flow and has direct neuroprotective properties through its bilobalide and ginkgolide content. In a randomised, placebo-controlled, double-masked crossover trial, Quaranta et al. (2003) gave 27 patients with bilateral visual field damage from normal-tension glaucoma 40 mg of standardised Ginkgo biloba extract three times daily for 4 weeks vs placebo. Mean visual field defect (the standard "MD" measure on Humphrey perimetry) improved from −11.40 dB to −8.78 dB after Ginkgo (p=0.0001), with no significant change on placebo. [4]

The benefit is most relevant in normal-tension glaucoma where vascular factors dominate, and the typical dose used in studies is 120 mg/day of standardised 24% flavone glycoside / 6% terpene lactone extract (the EGb 761 formulation). Ginkgo modestly inhibits platelet aggregation, so people on anticoagulants (warfarin, DOACs) or who are scheduled for surgery should discuss with their physician before starting. See our Ginkgo Biloba page for a fuller overview of the herb.

Magnesium — for Vasospasm and Field Defects

Magnesium relaxes vascular smooth muscle and improves microcirculation. In a small randomised study, 15 normal-tension glaucoma patients given 300 mg/day of oral magnesium citrate for one month showed significant improvement in visual field mean deviation and pattern standard deviation compared with 15 untreated controls (p<0.05). [5] Color Doppler imaging of orbital vessel flow did not change significantly, suggesting the benefit may be at the microcirculatory level rather than in the larger arteries.

A practical magnesium target is 300–400 mg/day of well-absorbed forms — magnesium citrate, glycinate, or malate. People with kidney disease should consult their physician before supplementing. See our Magnesium page for forms and dosing.

Bilberry + Pine Bark (Mirtogenol) — Modest IOP Reduction and Better Blood Flow

Mirtogenol combines standardised bilberry extract (Mirtoselect, 80 mg) with French maritime pine bark extract (Pycnogenol, 40 mg). Steigerwalt et al. (2008) studied 38 asymptomatic subjects with intraocular hypertension. After 3 months of supplementation, IOP fell from a baseline of 25.2 mmHg to 22.0 mmHg (about 13% reduction), significantly more than untreated controls, and ocular blood flow in the central retinal, ophthalmic, and posterior ciliary arteries improved on Color Doppler imaging. [6] This is not a substitute for prescription drops, but the combination of modest pressure-lowering with improved ocular perfusion has theoretical appeal for ocular hypertension and as an adjunct in established glaucoma.

Lifestyle Factors That Actually Move the Needle

Aerobic exercise lowers IOP by 1–5 mmHg both acutely and with regular practice. Walking, cycling, swimming, and zone-2 cardio are all helpful. See our Zone 2 Cardio page for the rationale.
Avoid head-down inversions in yoga (headstand, downward dog held for long periods) — these can spike IOP by 10–15 mmHg. People with glaucoma should choose modified poses.
Sleep position — sleeping with the head elevated 20–30 degrees reduces overnight IOP, which can help in advanced glaucoma where nocturnal pressure spikes drive progression.
Caffeine can transiently raise IOP by 1–4 mmHg in susceptible people for an hour or two. Moderate intake (1–2 cups of coffee) is generally fine, but avoid chugging large amounts before pressure measurements or all in one sitting.
Stay hydrated steadily — drinking large volumes of water rapidly (over 1 litre in 5 minutes) can spike IOP. Sip throughout the day instead.
Don't smoke — smoking accelerates optic nerve oxidative damage and is associated with worse glaucoma outcomes.
Manage sleep apnoea — untreated obstructive sleep apnoea is independently associated with normal-tension glaucoma progression. CPAP treatment matters.

What Doesn't Replace Drops

Be honest with yourself: every natural intervention discussed here is adjunctive. None of them lowers IOP as reliably as prostaglandin drops (which typically reduce pressure 25–35%), and stopping prescribed treatment to rely on supplements alone is the single most common cause of preventable glaucoma vision loss. Use these to support your eye health and your optic nerve metabolism — but keep your appointments, take your drops on schedule, and report side effects rather than stopping medications on your own.

Evidence Review

Global Burden — Tham et al. 2014 (PMID: 24974815)

Tham and colleagues conducted a systematic review and Bayesian meta-analysis of 50 population-based studies covering 3,770 cases of primary open-angle glaucoma (POAG) among 140,496 examined individuals and 786 cases of primary angle-closure glaucoma (PACG) among 112,398 individuals. Global prevalence of glaucoma in adults aged 40–80 was estimated at 3.54% (95% credible interval 2.09–5.82). The number of affected adults was estimated at 64.3 million in 2013, projected to reach 76.0 million by 2020 and 111.8 million by 2040. POAG prevalence was highest in Africa (4.20%), and PACG was highest in Asia (1.09%). The projection assumes ageing demographics; actual incidence rates per age group are not necessarily increasing.

Vitamin B3 in Mice — Williams et al. 2017 (PMID: 28209901)

Williams and colleagues, working in the John lab at the Jackson Laboratory, used the DBA/2J mouse model of inherited high-pressure glaucoma. They showed that retinal NAD+ levels declined with age before clinical glaucoma developed and that mitochondrial vulnerability was an early driver of retinal ganglion cell dysfunction. Oral supplementation with nicotinamide (a NAD+ precursor) was given prophylactically and as a rescue intervention. At the highest dose (2,000 mg/kg/day in drinking water), 93% of eyes showed no detectable glaucoma over the experimental period, vs significant pathology in untreated controls. Combining nicotinamide with AAV-mediated overexpression of Nmnat1 (an enzyme that drives NAD+ synthesis) produced near-complete protection. The Science paper established mitochondrial NAD+ depletion as a mechanism of glaucomatous neurodegeneration and identified nicotinamide as a candidate human intervention.

Nicotinamide RCT — Hui et al. 2020 (PMID: 32721104)

Hui and colleagues at the Centre for Eye Research Australia ran a crossover, double-masked, randomised, placebo-controlled trial in 57 glaucoma patients already on standard IOP-lowering therapy. Each participant received 6 weeks of 1.5 g/day nicotinamide, then 6 weeks of 3.0 g/day, followed by crossover to placebo (or vice versa) without washout. The primary endpoint was photopic negative response (PhNR) Vmax — an electrophysiological measure of retinal ganglion cell function. Improvement beyond the 95% coefficient of repeatability was observed in 23% of participants on nicotinamide vs 9% on placebo. Mean PhNR Vmax improved 14.8% on nicotinamide vs 5.2% on placebo; the Vmax ratio (a normalisation against the b-wave) improved 12.6% vs 3.6%. This is a relatively short trial assessing a functional surrogate rather than visual field preservation over years, but it is the first human evidence that the dramatic mouse effect from Williams 2017 partially translates to people. The trial did not find an IOP-lowering effect, consistent with the mechanism being neuroprotective rather than pressure-related. Larger and longer trials measuring visual field outcomes are ongoing.

Ginkgo Biloba — Quaranta et al. 2003 (PMID: 12578781)

Quaranta and colleagues conducted a prospective, randomised, placebo-controlled, double-masked crossover trial in 27 patients with bilateral visual field damage from normal-tension glaucoma. Patients received 40 mg of Ginkgo biloba extract three times daily for 4 weeks, then an 8-week washout, then 4 weeks of identical-appearing placebo (40 mg fructose), with the order randomised. Visual field indices were measured by Humphrey perimetry. After Ginkgo, mean deviation (MD) improved from −11.40 ± 3.27 dB to −8.78 ± 2.56 dB (p=0.0001), and corrected pattern standard deviation (CPSD) improved from 10.93 ± 2.12 dB to 8.13 ± 2.12 dB (p=0.0001). No significant changes were observed during placebo. The investigators interpreted the benefit as a combination of improved ocular blood flow (Ginkgo flavones are vasodilators) and direct neuroprotective effects (terpene lactones inhibit platelet-activating factor and have antioxidant activity). The trial is small and short, but the magnitude of within-subject improvement is unusual for visual field testing where regression to the mean is expected, lending credibility to the result.

Magnesium — Aydin et al. 2010 (PMID: 19882529)

Aydin and colleagues studied 30 patients with normal-tension glaucoma randomised to 300 mg/day oral magnesium citrate for one month versus no treatment (15 per group). At one month, mean deviation and pattern standard deviation on Humphrey perimetry improved significantly in the magnesium group (p<0.05), with no change in controls. Color Doppler imaging of the ophthalmic, central retinal, and short posterior ciliary arteries did not show significant changes in resistive or pulsatility indices, suggesting the magnesium benefit may operate at the microcirculatory level (capillaries, retinal arterioles) rather than in vessels measurable by Doppler. This is a small trial without a placebo control — improvement could partly reflect learning effects on perimetry — but the results are consistent with the broader literature on magnesium's vascular and neurotrophic effects, and the dose used is achievable through diet plus a modest supplement.

Mirtogenol — Steigerwalt et al. 2008 (PMID: 18618008)

Steigerwalt and colleagues studied 38 subjects with asymptomatic ocular hypertension (baseline IOP ~25 mmHg). Twenty received Mirtogenol (a fixed combination of 80 mg standardised bilberry extract Mirtoselect plus 40 mg French maritime pine bark extract Pycnogenol) daily; 18 served as untreated controls. After 3 months, IOP in the Mirtogenol group fell to 22.0 mmHg, significantly lower than baseline and untreated controls (p<0.05). Nineteen of 20 treated subjects had a measurable IOP decrease. Color Doppler imaging of the central retinal, ophthalmic, and posterior ciliary arteries showed significant improvement in both systolic and diastolic flow components. The mechanisms proposed are improved nitric-oxide-mediated vasodilation (from Pycnogenol's procyanidins) and reduced microvascular oxidative stress (from anthocyanins in bilberry). The trial lacks a true placebo and is small; subsequent independent replication has been mixed. The effect size on IOP (~3 mmHg) is meaningful but smaller than prostaglandin drops, and the supplement should not replace prescription therapy in established glaucoma.

Mechanism Review — Mozaffarieh et al. 2008 (PMID: 18334938)

Mozaffarieh, Grieshaber, and Flammer (the Basel group whose clinical observations defined Flammer syndrome) reviewed the role of unstable ocular oxygen supply in glaucomatous neurodegeneration. They argue that primary vascular dysregulation — a constellation of features including cold extremities, low blood pressure, migraine, and reduced ocular blood flow autoregulation — leads to fluctuating oxygen delivery to the optic nerve. Repeated cycles of ischaemia and reperfusion generate reactive oxygen species, particularly superoxide and peroxynitrite, that damage mitochondria and trigger apoptotic cell death in retinal ganglion cells. This framework explains why glaucoma can progress despite normal IOP and why interventions targeting blood flow (Ginkgo, magnesium, Mirtogenol) and mitochondrial energy metabolism (nicotinamide) have biological plausibility independent of pressure-lowering. The review is a synthesis rather than primary data, but its predictions have been borne out by subsequent intervention trials, including the nicotinamide work.

References

Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysisTham YC, Li X, Wong TY, Quigley HA, Aung T, Cheng CY. Ophthalmology, 2014. PubMed 24974815 →
Vitamin B3 modulates mitochondrial vulnerability and prevents glaucoma in aged miceWilliams PA, Harder JM, Foxworth NE, Cochran KE, Philip VM, Porciatti V, Smithies O, John SWM. Science, 2017. PubMed 28209901 →
Improvement in inner retinal function in glaucoma with nicotinamide (vitamin B3) supplementation: a crossover randomized clinical trialHui F, Tang J, Williams PA, McGuinness MB, Hadoux X, Casson RJ, Coote M, Trounce IA, Martin KR, van Wijngaarden P, Crowston JG. Clinical and Experimental Ophthalmology, 2020. PubMed 32721104 →
Effect of Ginkgo biloba extract on preexisting visual field damage in normal tension glaucomaQuaranta L, Bettelli S, Uva MG, Semeraro F, Turano R, Gandolfo E. Ophthalmology, 2003. PubMed 12578781 →
The effect of oral magnesium therapy on visual field and ocular blood flow in normotensive glaucomaAydin B, Onol M, Hondur A, Kaya MG, Ozdemir H, Cengel A, Hasanreisoglu B. European Journal of Ophthalmology, 2010. PubMed 19882529 →
Effects of Mirtogenol on ocular blood flow and intraocular hypertension in asymptomatic subjectsSteigerwalt RD, Gianni B, Paolo M, Bombardelli E, Burki C, Schonlau F. Molecular Vision, 2008. PubMed 18618008 →
Oxygen and blood flow: players in the pathogenesis of glaucomaMozaffarieh M, Grieshaber MC, Flammer J. Molecular Aspects of Medicine, 2008. PubMed 18334938 →