Dry eye symptoms arise when your cornea is inadequately lubricated. The disorder comes about because of insufficient tear volume or substandard quality of the tears, which leads to too rapid evaporation or rapid destruction of the tear film.

The tear film normally has three constituents: an outer layer of lipids secreted by the meibomian glands; an aqueous (water) middle layer produced by the lacrimal glands; and a mucous inner layer. A malfunction in any of these layers can lead to dry eye syndrome.

You may also experience dry eye symptoms if you unknowingly suffer from diseases such as eyelid inflammation (called blepharitis), Sjögren’s syndrome which causes dry eyes and dry mouth, and others.

N-Acetyl-cysteine (NAC)

The usefulness of N-acetyl-cysteine lies primarily in the fact that, an amino acid that contains sulphur. The sulphur component in cysteine gives it unique, highly versatile binding and structural capabilities in the body. example, your body needs cysteine to produce taurine, a valuable amino acid, and the powerful antioxidant glutathione.

Glutathione is made from the sulphur-bearing amino acid cysteine and two other amino acids. Diverse body functions benefit from the presence of glutathione. This potent antioxidant helps body cells recover after a stroke, protects against cancer, prevents sharp fluctuations in blood sugar, and protects arterial walls from damage.

Because it is the most easily absorbed form of cysteine, NAC has become the most common source of cysteine for therapeutic purposes. NAC can be found in animal proteins (fish, eggs, dairy, meat, and poultry) and some vegetable proteins (e.g. soybeans).

You are more vulnerable to disease and other ailments when glutathione levels in your blood are depleted. To enable higher glutathione production by the liver, you need to increase intake of NAC. NAC is a necessary ingredient for making reduced glutathione (GSH), the most useful, un-oxidised form of glutathione.

Because it leads to the increased production of glutathione, NAC helps prevent eye damage from oxidation and its associated toxic materials. Your eye uses glutathione as its principal antioxidant, and whilst, its highest concentration (aside from the liver, where it is produced) is in the eyes. Many research studies have directly linked low levels of glutathione with all types of eye diseases, so it is important to maintain normal glutathione levels to promote eye health.

As a drug, NAC is used to remove clumps of mucous in the body, such as in the lungs of patients with chronic emphysema, chronic bronchitis, cystic fibrosis, and pneumonia. As an antioxidant, NAC prevents lipids from being oxidised, which helps dissolve coagulations of mucous.

Its mucous-dissolving properties, makes NAC a powerful agent for treating problems associated with lipid oxidation in the eyes. Several studies have shown that treatment with NAC is able to produce better results than artificial tears in relieving the symptoms experienced by people with blepharitis. Trial doses involving 100mg of NAC taken three times daily improved the constitution of the tear film, reducing the symptoms of blepharitis.

Many research monographs have pointed to the beneficial effects of NAC on Sjögren’s syndrome, an autoimmune disease which also affects the eyes. NAC’s fast-acting ability to thin out mucosal secretions unblocks the cellular channels, allowing moisture to flow more freely. In several trials on people diagnosed with Sjögren’s syndrome, researchers found the associated dry eye symptoms improved with thrice-a-day doses of 200mg of NAC.