What are Dry Eyes?
The normal tear film on the surface of the eye is composed of three layers:
Bottom mucin layer
Middle liquid or water layer
Outer lipid or oily layer
People who suffer from dry eyes have one or more of these layers diminished causing the tear film to break down. This leads to an increase in the salt levels in the remaining tear film. The salt level or tear osmolarity increases either due to evaporation of the liquid layer from the eye (evaporative dry eye) or from inadequate production of the water layer. This increase in the salt levels causes an inflammatory reaction in the cells surrounding the eye which results in further damage to these cells. This inflammatory reaction causes many of the symptoms related to dry eyes and contributes to the progression of the disease. Just as there are no fish in the Dead Sea due to the high salt levels, the eye can only tolerate certain levels of increased osmolarity.
Three Anti-inflammatory Omega Fatty Acids Studied for Dry Eyes
Flaxseed Oil or Linseed Oil or ALA – Alpha Linolenic Acid
Flaxseed oil for use in dry eyes is not as efficient as the other omega fatty acids as the flaxseed oil must be converted in several steps into EPA found in fish. This is lees potent method for reducing inflammation.
Fish Oil or Eicosapentaeoic Acid –EPA and Docosahexaenoic Acid -DHA
Even though they have benefits for heart disease and age-related macular degeneration, there are not well controlled studies to date that show a significant benefit in dry eye patients. Epidemiological studies suggest that diets high in omega-3 fatty acids reduce the risk of dry eyes.
Black Current Seed Oil or Gamma Linolenic Acid- GLA Omega-6 Fatty Acid
GLA is an anti-inflammatory omega-6 fatty acid not found in fish oil, flaxseed oil or our diet. GLA is converted into an anti-inflammatory prostaglandin-PGE1 which plays an important role in the tear glands and ocular surface.
Ocular Benefits of GLA in the Tear Film
Liquid or Aqueous Layer
GLA stimulates aqueous or liquid layer production. It is thought to be secondary to the production of the anti-inflammatory prostaglandin PGE1 from GLA which is required in the secretion of tear and saliva.
GLA + EPA together have been shown to improve mucin production.
Lipid or Oily Layer
In Meibomian gland dysfunction (produce the lipid layer), GLA has been shown to improve lipid turbidity and Meibomian gland obstruction.
GLA Studies Benefits in Dry Eye Problems
Significant improvement in the ocular surface, reduction of dry eyes symptoms, and a improved tear film levels of PGE1.
Tear-Deficient Dry Eyes
Gal improved symptoms, ocular inflammation, and staining of cells on the surface of the eye.
Contact Lens Comfort
GLA improves contact lens comfort and dry eyes symptoms.
Post LASIK or PRK
GLA improved dry eye symptoms after surgery.
GLA Benefits for Other Health Conditions
GLA has shown promise in rheumatoid arthritis and diabetic retinopathy. GLA may help immune-function in the elderly and improve lipid profiles.
Omega-6 Fatty Acids
Omega-6 fatty acids of the arachidonic acid type (which are over-abundant in the American diet-meat and dairy) are converted into pro-inflammatory compounds. Omega-6 fatty acids like GLA from black currant seed is converted into anti-inflammatory PGE1. The type of omega-6 fatty acid is extremely important in our diet or supplements that we take.
HydroEye is a supplement developed for the treatment of dry eyes. The main component in HydroEye is gamma lenolenic acid. HydroEye contains other ingredients to help with the efficiency of GLA.
Vitamin A supports mucin production.
Vitamin C supports aqueous production and is a cofactor in fatty acid metabolism.
Vitamin B6 and Magnesium
Vitamin B6 and magnesium are cofactors in the metabolism of omegas into anti-inflammatory prostaglandins.
Fish Oil Omega-3 Fatty Acids- EPA
Addition of EPA blocks the conversion of GLA into arachidonic acid which is the pro-inflammatory prostaglandin.
GLA has show to be useful in the treatment of dry eyes and should be considered an important part of the treatment regime for dry eyes.