Dry eye treatment: the whole picture

The body requires consumption of the essential oils for lubrication of the joints and the eyes, as well as for restoration of normal lubrication to the body. The important fats, especially the omega-3 oils, are polyunsaturated and are found in cold-water fish, flaxseeds and walnuts. There has been a large amount of debate on the nutritional aspects of treating dry eye, but we now know that the fish oils and omega-6 essential fatty acids, in the right combination, can effectively treat this condition.

Recent scientific studies indicate that one of the major contributors to the accumulation of free radicals in the lacrimal, mucous and oil-producing glands of the eye and orbit may be nutritional deficiency. Scientific research over the past decade has shown that specifically targeted nutritional supplements can restore function to the glands, providing lubrication to the eye. It is this research that has led to the identification of specific nutrients that can restore and support improved tear function.

Oral nutritional formulations of essential fatty acids (EFAs) are being used to treat dry eye syndrome – some with more success than others. EFAs as an effective treatment for dry eye syndrome is dependent on the proper balance of both omega-6 and omega-3 EFA from chemically stable plant oil to consistently produce series one tear-specific anti-inflammatory prostaglandin (PGE1). EFA formulations will also block arachidonic acid (AA) fatty acid cleavage to the series two cyclooxygenase enzyme (COX2), which can convert to a pro-inflammatory series two prostaglandin (PGE2) without the nutrient cofactors that inhibit the formation of COX2.

EFA treatment of dry eye disease is dependent on specific nutrient cofactors that aid the downstream metabolic conversion to anti-inflammatory prostaglandins. These nutrient cofactors also stimulate the production of healthy goblet cells, as well as enhance production of clearer and thinner meibomian gland oil production.

Properly designed formulations will also stimulate lacrimal gland secretion, as well as stimulate the production of tear lactoferrin, the antiviral, antibacterial iron-binding protein that is particularly vital to the LASIK and other postoperative patients. Dry eye nutritional formulations that are based on the most recent science now include iron-free lactoferrin in the product. Serum lactoferrin is released from the eyelid in a manner similar to serum IgG, and possibly from tear neutrophils during infection and inflammation. By binding iron, lactoferrin prevents the pathogen from obtaining sufficient iron for growth.

The nutritional formulations that are designed around chemically stable omega-6 plant oils all contain linoleic acid (LA) and significant amounts of gamma linolenic acid (GLA), plus the nutrient cofactors necessary to ensure the delta 6 desaturase (D6D) enzymatic metabolic conversion to the tear-specific anti-inflammatory PGE1. They also contain varying amounts of omega-3 alpha linolenic acid (ALA), which converts to EPA and DHA.

To back up this plant-based ALA/EPA/DHA conversion, products include small amounts of mercury-free fish oil, which contains DHA and EPA necessary to block the delta-5-desaturase (D5D) enzymatic AA cleavage of the omega-6 downstream DGLA metabolite by the COX2 enzyme. This enzyme, if not blocked, can convert omega-6 DGLA to the pro-inflammatory series two prostaglandins (PGE2). Early dry eye nutritional products did not address the AA/COX2 cleavage issues as they pertain to the downstream conversion of EFA to anti-inflammatory prostaglandins.

Some manufacturers are designing formulations that are focused on the metabolic action of the omega-3 EFA, primarily found in flax and fish oils. The omega-3 EFA also requires nutrient cofactors to consistently convert downstream to EPA and DHA, which subsequently convert to the anti-inflammatory series three prostaglandins (PGE3). PGE3 is an important site-specific anti-inflammatory, particularly for the rheumatoid arthritis patient, but not as specific to tears as the series one prostaglandins from the omega-6 fatty acid metabolites.