Dry eye can be a complex disease of the tears and eye surface resulting in symptoms of discomfort, impaired vision, and tear film instability. There are two main causes that dry eyes can be subdivided into:
- Low tear volume
- Accelerated tear evaporation
Dry Eyes Are Common and Costly
Around the world, the prevalence of people suffering from dry eye ranges from 7% to 33% and increases significantly with age. Dry eyes can have a negative impact on the quality of life of those with this disease and is often a chronic condition.
Of those patients with severe dry eye, it is estimated that less than 30% of patients use medicated drops to manage their symptoms, whereas approximately 60% opt for using artificial tears.
The management of dry eye causes a substantial economic burden, with annual costs estimated at $3.4 billion dollars in the United States. When considering additional indirect costs such as a reduction in the productivity of individuals with this disease, the costs increase to $55.4 billion.
Although most recommended treatments include artificial tears, tear stimulating drugs, or medicated eye drops, there are several natural remedies and prevention strategies that may help in preventing symptoms of dry eyes.
Curcumin is present in the Indian spice turmeric and has been found to have anti-inflammatory, antioxidant, and anti-tumor properties. In research studies in a laboratory, curcumin can reduce the expression and activation of inflammatory signals in skin cells that are typically responsible for alterations in tears at the eyes surface. Therefore, it is believed curcumin can be used to decrease the inflammation present in those with dry eye disease, as well as reduce symptoms. There are no clinical studies looking at curcumin and dry eyes.
There is evidence to suggest that vitamin D deficiency may contribute to dry eye syndrome, with data showing an association between dry eyes and serum levels of 25-hydroxyvitamin D. In an observational study involving 105 subjects with dry eye that were unresponsive to conventional treatment who also had vitamin D deficiency, supplementation with an injection of cholecalciferol was found to be effective in relieving the symptoms.
Vitamin D supplementation was found to promote tear secretion, reduce tear evaporation, and decrease inflammation on the eye surface and eyelid margin. Additional studies have also shown the benefit of oral vitamin D supplementation in relieving symptoms of dry eye even in those without vitamin D deficiency.
Oxidative stress may be involved in injury to cells of the eye surface causing surface inflammation that results in dry eye disease. Due to the role of oxidative stress, several antioxidants appear to improve the tear film and the symptoms patients experience with dry eye disease.
In a cross-over randomized controlled clinical study evaluating the effects of oral supplementation with a combination supplement composed of vitamin B2, C, E, selenium, and zinc, patients were found to have significant improvement in tear stability and also clinical symptoms of dry eye.
Another study evaluating the effects of an oral antioxidant supplement containing anthocyanosides, astaxanthin, vitamins A, vitamin C, vitamin E, and Chinese herbal extracts (Cassiae semen and Ophiopogonis japonicas) found increased tear production, improved tear film stability, and decreased dry eye symptoms in subjects receiving the supplement.
From these studies and those alike, it is evident that antioxidants play a role in treating dry eye. However, it is unclear if individual vitamins are more effective than others since the studies used combinations rather than studying individual vitamins.
Omega- 3 Fatty Acids
Omega-3 fatty acids are composed of eicosapentaenoic acid (EPA), docosahexanoic acid (DHA), and alpha-linoleic acid (ALA), and are essential fatty acids that cannot be synthesized by the human body, therefore requiring supplementation in the diet. These fatty acids play an essential role in eye health by way of their anti-inflammatory properties. Omega-3 fatty acids reduce cytokines and block inflammatory eicosanoids that have been shown to play a significant role in the disease process of dry eye.
Several studies have shown the benefit of omega-3 supplementation and dry eye disease.[12,13] One of the larger, prospective, randomized controlled clinical studies evaluated the role of omega-3 fatty acids in patients with diets that lacked omega 3-fatty acids. The results showed that oral supplementation with omega-3 fatty acids in a 500mg capsule form (325 mg EPA and 175 mg DHA) twice daily for 3 months both improved dry eye symptom and enhanced the tear-film-breakup time.
The cause of dry eye in some people is due to Meibomian gland dysfunction (the oil-producing glands along the eyelid) which results in increased evaporation of the tear film. Several clinical trials have investigated the use of hot compresses, eyelid warming masks/goggles, infrared heaters, and eyelid massage as a treatment for dry eye disease.[15-18] These therapies clinically improved dry eye by reducing Meibomian gland duct obstruction, and also increased tear film stability and lipid layer thickness of the tear film.[15-17]
Modifying the Environment
In addition, by modifying your environment by using humidifiers and avoiding air conditioning, sun, dust, and wind may also help to relieve dry eye symptoms by reducing the chance of inflammation.
Overall, despite the large number of people affected by dry eyes, there has yet to be an established treatment algorithm to effectively manage the symptoms experienced by those with the disease. Nevertheless, there seem to be several supplements that are promising. Although various types of medications are available, it is, in fact, possible that incorporating some of these natural supplements into the diet and modifying eyelid hygiene habits may prove to be effective in treating dry eye in some individuals.