This article considers the role of nutritional supplements as part of the management approach for patients with dry eye disease.
Dry eye disease is a common complaint that affects a large proportion of the UK population. It is difficult to establish the exact prevalence of dry eye because there is no single classification of the disease and it is multifactorial with many possible causes. One of the biggest risk factors is age, with studies suggesting that anywhere between 5–30% of patients aged 50 and above suffer from dry and uncomfortable eyes.1
Artificial tears seem to be the first treatment option and there is no shortage of brand choice and formulation, each advertised to treat a specific subset of the condition. Heated eye masks are now common along with a large variety of lid hygiene products. Although we seem to be making large strides in all of these areas, there is one significant omission – nutritionals. And this isn’t just from anecdotal evidence – the NHS website doesn’t acknowledge nutrition as a possible management intervention for dry eye,2 and neither does the College of Optometrists.3
Dry eye risk factors
Computers and tablets play a central role in most modern work environments and the increase in their use may be fuelling the rates of dry eye. Studies have shown that when someone uses a VDU their blink rate drops from an average 22 blinks per minute to a rate of just seven.4 This decreased blink rate leads to more tear evaporation and as a consequence, dry eye symptoms may result. The reason why people blink less when using a VDU is thought to be linked to visual concentration,5 so this reduced blink rate is not only associated with the computers at work, but also hand held devices that we use far more frequently, such as smartphones. According to OFCOM, the average person uses a smartphone for two hours per day, and this is likely to be in addition to their VDU use at work.
Contact lenses are another consideration with dry eye being a significant reason for patients to discontinue wear.6 Contact lenses themselves may actually increase the prevalence of dry eye, with these patients 12 times more likely to suffer than emmetropes.7
Myopia rates are increasing rapidly, with the incidence doubling in the last 50 years.8 Some of the most successful treatment options for myopia control rely on contact lens interventions such as orthokeratology and multifocal soft contact lenses. Using all the available tools we have to manage dry eye could be increasingly important in this area.
The role of supplements
The link between nutrition and dry eye disease has been the focus of research for over 20 years with the majority of the literature showing that omega-3 is an effective treatment option. Omega-3 is a polyunsaturated fat and along with omega-6 is one of the essential fats that we need in our diet for optimal health. Omega-6 is present in a large variety of foods, and it is unlikely that anyone would be deficient. However, omega-3 is less easy to obtain with one of the largest sources being oily fish. The balance between omega-6 and omega-3 is thought to be key for good health with an ideal ratio being around 3:1; the current western diet is thought to be around 16:1.9 One of the main reasons for this is because the UK population as a whole does not eat enough fish, especially the oily varieties such as salmon and sardines.10 The common food sources of omega-3 and omega-6 are summarised in Figure 1 (Distribution of omega-3 and omega-6 in common sources).
One of the easiest ways to address this imbalance is to supplement with omega-3. Table 1 provides a summary of the literature showing the impact of omega-3 supplementation (Table 1: An overview of the impact of omega-3 supplementation on dry eye).
The significance of dry eye type
Dry eye disease is a multifactorial condition and there are many different types (see Figure 2: Types of dry eye). Management needs to be tailored for the type of presentation - treatment for a patient who is aqueous deficient will be different from a patient who has evaporative dry eye. Studies suggest that meibomian gland dysfunction (MGD) is the leading cause of dry eye disease,19 with some suggesting that it could account for over 85% of the cases.20 A summary of the literature which considers the impact of omega-3 in the management of MGD is provided in Table 2 (Table 2: Overview of literature on the effect of omega-3 on meibomian glad dysfunction).
Options for supplementation
One way to supplement levels of omega-3 is to increase the amount of oily fish in the diet and having a hand out available for patients to take with them regarding this is useful. Not all patients will want to increase their fish intake, and this is where nutritional supplements can play a role. Some clinicians prefer to direct their patients to the nearest supermarket or health store, and allow them pick their own omega-3 product; this can mean that patient’s fail to source these products after they have left the practice. Suggesting a specific product is better, and stocking a supplement in practice can help improve the likelihood of uptake.
While all supplements have the potential for toxicity, suggesting a supplement specifically designed for eye health can reduce the chances of the patient self-selecting a very high dose supplement.
While omega-3 is clearly the most effective nutritional for dry eye it is not the only nutrient to consider. Studies have shown that antioxidant vitamins and minerals can improve dry eye symptoms,25 and may play a role in preventing omega-3 supplements from becoming rancid. A recent study found that omega-3 enriched eggs were much more stable when antioxidants were also present.26 Many dry eye specific supplements incorporate omega-3 and antioxidants for increased stability and improved absorption. Further, fish oil alone does not address the role of oxidative stress in tear film dysfunction, and some additional nutritional formulations have been designed that incorporate both fish oil and nutritional co-factors.27
There are many products available designed for eye health and some that focus on dry eye specifically. Deciding on the brand will depend on individual research and personal preference.
While a lot of studies have used high concentrations of omega-3 such doses are typically not available in eye-specific products. As a result, significant improvements to the clinical picture may not be apparent until three months after commencing treatment; this will depend on the patient’s dietary levels to begin with. It is, therefore, a good idea to review patients after an appropriate period of time to allow for the supplements to have their desired effect.
The role of optical professionals is ever expanding. This can be quite daunting and is perhaps one of the reasons why supplements have not played a bigger role in the treatment of dry eye disease. With the increasing incidence of DED ensuring our patients receive treatment has never been more important. Adding nutritionals to our ever expanding arsenal of tools for the treatment of dry eye could have a big impact on our patients’ well being.
About the author
Iain Johnson is a dispensing optician with additional expertise within the field of nutrition. He has written articles relating to nutrition and eye health for publication and lectures on the role of nutritional supplements within optometric practice.
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- NHS. Dry Eye Syndrome. http://www.nhs.uk/Conditions/Dry-eye-syndrome/Pages/Treatment.aspx (accessed 24 February 2017)
- College of Optometrists. Clinical Management Guidelines. Dry Eye (Keratoconjunctivitis Sicca, KCS). https://www.college-optometrists.org/guidance/clinical-management-guidelines/dry-eye-keratoconjunctivitis-sicca-kcs-.html (accessed 24 February 2017)
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- Schlote T, Kadner G, Freudenthaler N. Marked reduction and distinct patterns of eye blinking in patients with moderately dry eyes during video display terminal use. Graefe's archive for clinical and experimental ophthalmology. 2004 Apr 1;242(4):306-12
- Johnson and Johnson. Balance on contact lens properties. https://www.jnjvisioncare.co.uk/education/quick-learning-by-topic/balance-of-properties/introduction (accessed 20 June 2016)
- Fuller D. Yes, dry eye patients can wear contacts: ocular surface compromise is historically a contraindication, but evidence shows technology is turning that old wisdom on its head. Review of Optometry. 2015 Aug 15;152(8):40-6.
- College of Optometrists. Study shows myopia prevalence in children in the UK has more than doubled in the last 50 years. https://www.college-optometrists.org/the-college/media-hub/news-listing/nicer-myopia-children.html (accessed 24 February 2017)
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- Miljanović B, Trivedi KA, Dana MR et al. Relation between dietary n− 3 and n− 6 fatty acids and clinically diagnosed dry eye syndrome in women. The American journal of clinical nutrition. 2005 Oct 1;82(4):887-93.
- Kangari H, Eftekhari MH, Sardari S et al. Short-term consumption of oral omega-3 and dry eye syndrome. Ophthalmology. 2013 Nov 30;120(11):2191-6.
- Liu A, Ji J. Omega-3 essential fatty acids therapy for dry eye syndrome: a meta-analysis of randomized controlled studies. Medical science monitor: international medical journal of experimental and clinical research. 2014;20:1583.
- Bhargava R, Kumar P, Phogat H et al. Oral omega-3 fatty acids treatment in computer vision syndrome related dry eye. Contact Lens and Anterior Eye. 2015 Jun 30;38(3):206-10.
- Kawakita T, Kawabata F, Tsuji T et al. Effects of dietary supplementation with fish oil on dry eye syndrome subjects: randomized controlled trial. Biomedical Research. 2013;34(5):215-20.
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- Nelson JD, Shimazaki J, Benitez-del-Castillo JM et al. The international workshop on meibomian gland dysfunction: report of the definition and classification subcommittee. Investigative ophthalmology & visual science. 2011 Mar 1;52(4):1930-7.
- Lemp MA, Crews LA, Bron AJ et al. Distribution of aqueous-deficient and evaporative dry eye in a clinic-based patient cohort: a retrospective study. Cornea. 2012 May 1;31(5):472-8.
- Bhargava R, Kumar P, Kumar M et al. A randomized controlled trial of omega-3 fatty acids in dry eye syndrome. International journal of ophthalmology. 2013;6(6):811.
- Macsai MS. The role of omega-3 dietary supplementation in blepharitis and meibomian gland dysfunction (an AOS thesis). Trans Am Ophthalmol Soc. 2008 Dec;106:336-56.
- Korb DR, Blackie CA, Finnemore VM et al. Effect of using a combination of lid wipes, eye drops, and omega-3 supplements on meibomian gland functionality in patients with lipid deficient/evaporative dry eye. Cornea. 2015 Apr 1;34(4):407-12.
- Malhotra C, Singh S, Chakma P et al. Effect of Oral Omega-3 Fatty Acid Supplementation on Contrast Sensitivity in Patients With Moderate Meibomian Gland Dysfunction: A Prospective Placebo-Controlled Study. Cornea. 2015 Jun 1;34(6):637-43.
- Drouault-Holowacz S, Bieuvelet S, Burckel A et al. Antioxidants intake and dry eye syndrome: a crossover, placebo-controlled, randomized trial. European journal of ophthalmology. 2009 May 1;19(3):337.
- Ren Y, Perez TI, Zuidhof MJ et al. Oxidative stability of omega-3 polyunsaturated fatty acids enriched eggs. Journal of agricultural and food chemistry. 2013 Nov 13;61(47):11595-602.
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