Nitric Oxide Shown to Lower Intraocular Pressure Naturally

Why is nitric oxide important for vision?

nitric oxide beets
Beets contain dietary nitrates. Your body converts them to nitric oxide.

Nitric oxide, one of the principal oxides of nitrogen, is produced naturally to assist with many health aspects. It contributes to vasodilation, relaxing the muscles that line your blood vessels allowing them to widen and improve circulation.  In that capacity it allows nutrients and oxygen to travel throughout the body efficiently.

As a free radical, in excess, nitric oxide (NO) contributes to inflammation, so should only be taken in recommended dosages.  In a balanced system, it is beneficial and can actually reduce inflammation. And in the case of glaucoma, it can be helpful in reducing elevated eye pressure (IOP) naturally.

Note: Nitric oxide should not be confused with nitrous oxide, a gas that dentists use to help patients relax.

Glaucoma factors

Trabecular mesh blockage. One cause of glaucoma is blockage of the trabecular mesh that permits excess aqueous humor to leave the eye.  Such blockage increases intraocular pressure (IOP).  Nitric oxide can help modulate the outflow of the aqueous humor outflow system, directly improving outflow through the trabecular meshwork, and other delicate structures (Schlemm’s canal and distal scleral vessels). This helps reduce eye pressure (IOP) naturally.1

Schlemm’s canal shear stress. After passing through the trabecular meshwork, aqueous outflow passes through the pores of the Schlemm’s canal (SC).  The lining of the SC is similar to, but not the same as lymphatic channel or blood vessel linings.2 The SC lining may be more or less stiff – such contractility is directly related to the ability of outflow to pass through it.

Reduced cell contractility in the Schlemm’s canal (SC) appears to cause increased shear stress which reduces aqueous humour outflow through delicate SC pores.  In a human blood vessel, shear stress refers to the fact that blood flow parallel (tangential) to the walls of the vessel tends to collapse it. The lining of the SC has a similar shear stress sensitivity, which is regulated by NO.3

Cell contractility. The conventional wisdom about IOP has been that passive movement of excess aqueous humor is the principal factor in normal IOP. But researchers have discovered that active cell contractility contributes to outflow.  Contractility (as opposed to contractibility) is the ability (of muscles) to be able to contract or expand.

Scientists inhibited cellular metabolism in mice and observed that cell contractility and aqueous outflow were quickly reduced.4 The ability then, of cells in the Schlemm’s canal, to resist collapse due to shear stress, is important.

Nitric oxide plays a vital role in the eye by regulating SC cell contractility and permeability of endothelial cells in response to either biochemical or biomechanical cues. This regulatory response is complex but new research demonstrates that NO signaling is key because enhancing or inhibiting NO dramatically affects outflow function by controlling a feedback loop.5

Glaucoma diagnosis

In determining a glaucoma diagnosis, the primary factors are taken into consideration by the eye doctor:

      1. Changes in the optic nerve
      2. Reduction in peripheral vision
      3. Intraocular Pressure (IOP) which in general has the normal range of 8-20 hg/ml

Primary open-angle glaucoma where the IOP is above normal is the most common form of glaucoma, though a patient can have similar symptoms even with normal and low IOP (see below for natural supplement recommendations related to helping keep the optic nerve nourished, healthy, resilient and strong).

Other risk factors include ischemia, inflammation, myopia, race, age, and low ocular perfusion pressure.6

Other nitric oxide benefits

In the cardiovascular system, nitric oxide controls vascular tone, dilates vessels, and inhibits blood clotting. In the nervous system, it acts as a neurotransmitter and increases oxygen flow to the brain. In the respiratory system, it dilates blood vessels in the lungs, and is beneficial in respiratory distress, but is produced in abnormal amounts in lung inflammation conditions. In the immune system, it helps to modulate T cell-mediated immune response.7

Low-tension glaucoma

Low-tension glaucoma accounts for approximately 25 to 30 percent of all glaucoma cases, which means other factors are involved in vision loss not related to high eye pressure.  These may include:8

      • Reduced blood flow
      • Early nerve cell death
      • Nerve irritation
      • Excess glutamate production
      • Autoimmune disease

Several factors, such as hypercholesterolemia, diabetes, aging, and hypertension are established risk factors for atherosclerosis, in particular by decreasing the availability of nitric oxide. Arginine, a semi-essential amino acid, plays a major nutritional and metabolic role, and is a precursor of nitric oxide. Ann Biol Clin (Paris) Sep-Oct 2005;63(5):443-55.

Magnesium citrate. The lack of essential nutrients nourishing the optic nerve is one likely cause of normal-tension glaucoma due to poor circulation to the optic nerve. Magnesium can help improve blood flow, although one small study reported that magnesium did improve the visual field, but it did not affect ocular blood flow.9

Other mechanisms than blood flow may be responsible for the improvement.  For example, magnesium does promote regeneration (in the sciatic nerve) and reduces inflammation.10 Magnesium citrate has many health benefits including regulating blood sugar levels to boosting athletic performance, magnesium is crucial for your brain and body.

But note that magnesium citrate is commonly sold as a laxative and it may have interactions with some drugs such as those for HIV treatment, some antibiotics, hepatitis, and acne.11

PEA (Palmitoylethanolamide) – a number of studies show that this nutrient helps reduce IOP. It also providing protection against neurotoxic damage to the central nervous system and eye.

Recommended Products

Nitric Oxide Supplement

Magnesium Citrate 150 mg 90 vegcap

Dr. Grossman’s Bilberry/Ginkgo Combination 2oz (60ml) – wild crafted tincture.

Optic Nerve Eye Pressure and Optic Nerve Support Package 1

Optic Nerve Eye Pressure and Optic Nerve Support Package 2 – same as package 1 but added Nitric Oxide Supplement and Magnesium Citrate.

Advanced Eye & Vision Support Formula (whole food) 60 vcaps – our whole food, organic, GMO free eye formula


Natural Eye Care Series: Glaucoma (74 page paperback book)

Natural Eye Care Series: Glaucoma and Optic Nerve Support Package


  1. Dismuke WM, Mbadugha CC, Ellis DZ. (2008).  NO-induced regulation of human trabecular meshwork cell volume and aqueous humor outflow facility involve the BKCa ion channel. Am J Physiol Cell Physiol. 2008;294(6):C1378–C1386.
  2. Ramos RF, Hoying JB, Witte MH, Stamer WD. (2007). Schlemm’s canal endothelia, lymphatic, or blood vasculature? J Glaucoma. Jun-Jul;16(4):391-405.
  3. Ethier CR, et al. Biomechanics of Schlemm’s canal endothelial cells: influence on F-actin architecture. Biophys J. 2004;87(4):2828–2837.
  4. Reina-Torres E, Boussommier-Calleja A, Sherwood JM, Overby DR. (2020). Aqueous Humor Outflow Requires Active Cellular Metabolism in Mice. Invest Ophthalmol Vis Sci. Aug 3;61(10):45.
  5. Reina-Torres E, De Ieso ML, Pasquale LR, Madekurozwa M, van Batenburg-Sherwood J. (2021). The vital role for nitric oxide in intraocular pressure homeostasis. Prog Retin Eye Res. Jul;83:100922.
  6. Schuster AK, Wagner FM, Pfeiffer N, Hoffmann EM. (2021). Risk factors for open-angle glaucoma and recommendations for glaucoma screening. Ophthalmologe. Jul;118(Suppl 2):145-152.
  7. Abeyakirthi S. (2020). Nitric Oxide. Retrieved Apr 4 2022 from
  8. Murry MT. (2011). Magnesium Citrate Improves Vision in Normotensive Glaucoma. Retrieved Apr 4 2022 from
  9. Aydin B, Onol M, Hondur A, Kaya MG, Ozdemir H, et al. The effect of oral magnesium therapy on visual field and ocular blood flow in normotensive glaucoma. Eur J Ophthalmol. Jan-Feb 2010;20(1):131-5.
  10. Pan HC, Sheu ML, Su HL, Chen YJ, Chen CJ, et al. (2011). Magnesium supplement promotes sciatic nerve regeneration and down-regulates inflammatory response. Magnes Res. Jun;24(2):54-70.
  11. Cunha JP. (2021). Magnesium citrate. Retrieved Apr 4 2022 from