Dry Eye Syndrome (DES) is a disorder of the tear film due to either diminished tear production or excessive tear evaporation.

About 20-40% of adult population suffer from this condition which can be caused by a variety of things including contact lens wear, age, certain medications and environment. The number, however seems to be increasing every year as our use of electronic devices increases.

The problem has become so severe that its given rise to a new disorder: Computer Vision Syndrome (CVS).

Computer eyes

CVS consists of a series of eye and vision-related problems arising from prolonged use of digital screens (computer, tablet or mobile phone). Although these symptoms (one of the most common being dry eye) usually decrease by reducing the time spent on such devices, this is not always the case and, if not treated, they may worsen over time.

In a new study published in the journal Contact Lens & Anterior Eye researchers performed a randomised, double-blind, multicentre trial designed to assess the efficacy of dietary intake of omega-3 polyunsaturated fatty acids in symptoms of CVS including dry eye.

In this trial, 478 symptomatic patients were randomly assigned to two groups: one group received two capsules of omega-3 polyunsaturated fatty acids (180 mg of eicosapentaenoic acid [EPA] plus 120 mg of docosahexaenoic acid [DHA]) daily for three months and the other group received two capsules of olive oil.

The results demonstrated the beneficial effect of omega-3 in reducing symptoms of dry eye, reducing tear evaporation and other measures of eye health.

Supporting evidence

Other studies have also found benefit from omega-3 supplementation.

In one 2011 pilot study, dietary supplementation with omega-3 fatty acids in dry eye helped increase tear production and tear volume.

In another from 2013, two capsules of omega-3 (each containing 180 mg EPA and 120 mg DHA) daily for 30 days (compared to a placebo group received 2 medium-chain triglyceride oil capsules daily for 1 month) was associated with a decrease in the rate of tear evaporation, an improvement in dry eye symptoms, and an increase in tear secretion.

We have also reported on a study which showed benefit from a natural supplement containing omega-3 fatty acids and the herb fenugreek.

It is believed that omega-3 fatty acid supplementation may aid lubrication from the inside out, but also their anti-inflammatory properties may also be of benefit in cases of dry eye.

Visual impairment – sight loss often caused by eye disease, trauma, or a congenital or degenerative condition that cannot be corrected with glasses or contact lenses – is associated with a poorer quality of life and, when severe, loss of independence.

To help determine ways to decrease the growing burden of visual impairment, researchers from the University of Wisconsin School of Medicine and Public Health examined the relationships between the incidence of visual impairment and three modifiable lifestyle behaviours: smoking, drinking alcohol and staying physically active.

The research, published in the journal Opthalmology was conducted as part of the Beaver Dam Eye Study, a long-term population-based cohort study from 1988 to 2013 of nearly 5,000 adults aged 43 to 84 years.

Long-term protection

The researchers found that two of the behaviours studied were protective:

Physical activity Over 20 years, 6.7% of sedentary persons and 2% of physically active persons (people who engage in regular activity three or more times a week) developed visual impairment. After adjustment for age, these figures show a 58% decrease in odds of developing visual impairment in those who were physically active compared to those who were sedentary.

Occasional drinking Over 20 years, 11% of non-drinkers (people who have not consumed alcohol within the past year) developed visual impairment while 4.8% of occasional drinkers (those who have consumed alcohol in the past year, but reported fewer than one serving in an average week) did so. After adjustment for age, these figures show a 49% decrease in the risk of developing visual impairment in those who were occasional drinkers compared to those who consumed no alcohol.

The authors don’t specify what kind or ‘drinking’ – but previous evidence suggests a protective role for the antioxidant resverarol, found in red wine.

Likewise it seems the combination of being physically active and allowing yourself the occasional drink was most protective.

Over a period of 20 years, the incidence of VI in those who drank occasionally and were physically active was 5.9% compared with 25.8% in women who had not consumed alcoholic beverages over the past year and were sedentary.

Lifestyle changes

Heavy drinkers and smokers compared to people who never drank heavily and never smoked, has a small increase in risk for developing visual impairment.

“While age is usually one of the most strongly associated factors for many eye diseases that cause visual impairment, it is a factor we cannot change,” said Ronald Klein, M.D., MPH, lead researcher of the study.

“Lifestyle behaviours like smoking, drinking and physical activity, however, can be altered. So, it’s promising, in terms of possible prevention, that these behaviours are associated with developing visual impairment over the long term. However, further research is needed to determine whether modifying these behaviours will in fact lead to a direct reduction in vision loss.”

Vision loss a growing problem

It is estimated that by 2020, the number of people in the United States with visual impairment is projected to increase to at least four million. This is a 70% increase from 2000 and is due to the growing ageing population and prevalence of age-related eye diseases.

In the UK the number of people with sight loss is also set to increase dramatically. It is predicted that by 2050 the number of people with sight loss in the UK will double to nearly four million.

Visual impairment – sight loss often caused by eye disease, trauma, or a congenital or degenerative condition that cannot be corrected with glasses or contact lenses – is associated with a poorer quality of life and, when severe, loss of independence. It develops slowly over may years most estimates suggest that around 50% of sight loss can be avoided by taking proactive steps early in life to protect it.

See our article Seeing the benefits – protecting your vision for more practical suggestions.

Past observational studies have indicated a relationship between nutritional supplement use and eye health. However, randomized trial data on the effects of long-term multivitamin supplement use and risk of eye diseases are can be thin on the ground.

To address this, researchers based at Brigham and Women’s Hospital and Harvard Medical School – as part of the Physicians’ Health Study II (PHS II) – conducted a randomised, double-blind study of 14,641 US male doctors age 50 and older.

Half took a common daily multivitamin, as well as vitamin C, vitamin E and beta carotene supplements. The other half took a placebo.

The researchers followed the participants from 1997 to 2011 to see how many in each group developed new cases of two common eye diseases: cataract, which is a clouding of the eye’s lens, and age-related macular degeneration (AMD), the deterioration of the eye’s macula that is responsible for the ability to see fine details clearly.

The results were published in the journal Ophthalmology.

Good news for cataracts

The result showed that in the placebo group 945 cases of cataract developed, which were self-reported and confirmed by medical records, while only 872 cases of cataract developed in the multivitamin group, representing a 9% decrease in risk.

This risk was even lower, at 13%, for nuclear cataract, which occurs at the centre of the lens and is the most common variety of cataract associated with the ageing process.

The current study only looked at men, but in 2008 a study found that higher dietary intake of lutein/zeaxanthin and vitamin E, from food and supplements, significantly reduced the risk of cataracts in women.

A growing problem

The World Health Report published in 1998 by the World Health Organization estimated that there were 19.34 million people who are bilaterally blind (less than 3/60 in the better eye) from age-related cataract. This represented 43% of all blindness. The number of blind people in the world and the proportion due to cataract is increasing due to population growth and increasing longevity. These figures it said would hold true for less economically developed countries as well as the industrialised world.

These figures have not improved. The WHO now calculates that cataract is responsible for 51% of world blindness, which represents about 20 million people.

“If multivitamins really do reduce the risk of cataract, even by a modest 10%, this rather small reduction would nonetheless have a large public health impact,” said William Christen, ScD, the study’s lead author and researcher from Harvard Medical School.

Not enough to prevent AMD

In terms of AMD risk, the researchers found there were 152 new cases of visually significant AMD in the multivitamin group compared to 129 in the placebo group, but the difference was not considered statistically significant.

While this finding may seem to contradict results of other studies, such as Age-Related Eye Disease Study (AREDS) – long  considered the gold standard for nutritional research into AMD – the researchers note that the studies had different nutrient supplements, dosing and objectives.

AREDS included daily zinc and a high-dose antioxidant combination of vitamin E, vitamin C and beta carotene, and found that these reduced the risk of developing advanced age-related macular degeneration (AMD) by about 25%.

The supplement in PHS II included these nutrients at much lower doses, alongside many others, which were given at US Recommended Dietary Allowance dose levels, which are the minimum necessary to prevent deficiency, rather than the optimum needed to maintain health.

Official recommendations

The American Academy of Ophthalmology recommends the use of antioxidant vitamin and mineral supplements as recommended in the AREDS reports, including high daily doses of vitamin C, vitamin E, beta-carotene, zinc and copper only for patients who have intermediate or advanced AMD.

Current smokers and patients with a smoking history should take advice before taking beta-carotene because of the potential for an increased risk of lung cancer. The recent AREDS2 results would suggest other nutrients such as lutein and zeaxanthin may be an appropriate substitution for beta-carotene in the formulation.

In spite of these good outcomes, The Academy does not yet have a recommendation for the use of nutritional supplements to prevent cataracts or delay their progression.

The study, which was conducted at Friedrich Schiller University Jena, Germany, was part of the ongoing LUTEGA study, the aim of which is to study the effect of lutein and omega-3-fatty acids on the macular pigment.

It included 172 people, of which 145 completed the year-long study. The average age was 70. The participants’ eye health was assessed at the beginning of the study to provide a baseline measurement. They were then assessed 4 more times during the 12 months of the study.

Significant benefits

Participants were randomly divided into three groups:

• Group 1 received a once daily supplement containing 10 mg lutein, 1 mg zeaxanthin, 255 mg fish oil (100mg DHA, 30 mg EPA), 60 mg vitamin C, 20 mg vitamin E, 10 mg zinc, 0.25 mg copper
• Group 2 was given the same supplement as above but twice daily
• A third group was given a once a day placebo capsule

The volume of macular pigment increased from baseline by 20% in group 1 and by 28.4% in group 2, whereas it decreased in the placebo group. This indicates that supplementation improved response to certain colours and therefore improved vision

In addition to increasing macular pigment density the results also demonstrate that supplementation with this combination of antioxidant carotenoids and fatty acids significantly improved the plasma antioxidant capacity, circulating macular xanthophyll levels. These are important factors that could help reducing the risk of progression of the disease.

The role of oxidative stress

Age-related macular degeneration is a progressive disease that causes the degeneration of the macula, a yellow pigmented spot in the retina that results in diminished sharp and central vision. Central vision is important for daily tasks such as reading and driving. Oxidative stress has been implicated as a possible cause of macular degeneration.

Most commonly affecting people aged 50 and over, AMD rates around the globe are rising as the population ages and the number of people diagnosed with early AMD is projected to double by 2020.

Lutein and zeaxanthin, which are responsible for the protective yellow pigment, are the only two dietary carotenoids that physiologically accumulate in the macula. They act like ‘internal sunglasses’ protecting the eye against light-induced oxidative damage.

Because of this antioxidants, specifically lutein and zeaxanthin, because they are components of macular pigment, have been suggested to improve vision in macular degeneration.

The one-year randomised double-blind placebo-controlled trial performed by Chinese researchers recruited 120 healthy people aged between 25 to 47 years, who spent an average of 10 hours per day driving during the two years before the study started.

The participants were randomised to receive either 20mg lutein per day or a placebo for one year.

Lutein, along with zeaxanthin, is a carotenoid that helps protect eye health. Both of these nutrients, which are naturally yellow in colour, are found in high levels in the macula, the part of the eye responsible for detailed central vision.

The macula can be seen as a yellow spot near the centre of the retina and it gets its colour from the high levels of these carotenoids stored in it. Its yellow colour means it absorbs excess blue and ultraviolet light that enter the eye, and functions as biological sunglasses.

Significant improvements

The researchers measured visual acuity, blood lutein concentrations, visual performance and macular pigment optical density (MPOD, an indication of how much lutein is being stored in the macula), at regular intervals during the study.

Writing in the journal Nutrition the researchers noted that those taking the lutein had a small improvement in visual acuity (clear vision). More impressive was the significant rise in both serum lutein levels and central MPOD in those taking the supplement while no such changes were observed in the placebo group.

In addition, the researchers observed “significant increases in contrast and glare sensitivity,” especially in low light conditions. This, they said, suggested that supplementation with lutein may benefit driving at night and other visual tasks carried out under low light conditions.

Unique protection

Improvement in MOPD is important since a thin macular pigment lets in harmful blue light that destroys the eye cells (known as cones and rods).

Cones are used for vision in well-lit conditions, whereas the eyes switch over to rods for seeing in very low level light. Lutein and zeaxanthin are the only carotenoids with the unique ability to filter the harmful blue light that can damage cones and rods.

“The present findings” conclude the researchers ”provide convincing evidence that supplementation with lutein can significantly improve visual performance and vision related quality of life when ambient illumination is low”.

This finding echoes a large and growing body of human research showing that lutein can reduce the risk and incidence of age related macular degeneration, a major cause of blindness in the elderly. Adequate lutein, either through diet or supplements, can also slow down the formation of cataracts, a major cause of vision loss in the elderly. One small study has even suggested that lutein may improve vision in those with cataracts.

Getting more in your diet

Lutein is found in green leafy vegetables and in egg yolk and in fact it gives chickens their yellowish colour (at low concentrations it appears yellowish and at higher concentrations it is red-orange).

Other foods that supply lutein include nasturtium flowers (one of the richest sources), kale, dandelion leaves, broccoli, spinach, turnip greens, chard, watercress, corn, zucchini, and squash.

More and more multivitamins now have added lutein, but usually in a very small amount of 0.25 mg per tablet; far below the amount used in human clinical trials which is in the 10-20 mg per day range.

Now, doctors writing in the Canadian Journal of Ophthalmology say a combination of natural substances may hold the key to easing the condition.

Dry eyes occur when the eyes do not make enough tears, or the tears evaporate too quickly because the oil glands around the eyes, which help to keep eyes lubricated, are blocked or abnormal.  This leads to the eyes drying out and becoming inflamed and irritated.

Both men and women are affected by the condition but is particularly prevalent in women in the peri- and post-menopausal period.

In this recent a study researchers evaluated the effect of a natural supplement (Lacrisek, one capsule daily) containing plant-based phytoestrogen and other nutrients against a placebo in 66 post-menopausal women with dry eye syndrome.

The small 30-day study found that the supplement significantly increased tear production compared with the placebo-treated group. The supplement also significantly decreased tear osmolarity – that is the concentration of small proteins and electrolytes, including sodium, potassium, and chloride  in the tears. A balanced combination of these substances in our tears helps make them more efficient at keeping our eyes moist and protected.

Blood tests also revealed that the women, who all had low levels of sex hormones (17-β estradiol, estrone, and testosterone) at the beginning of the study showed a more normal hormone profile.

Multiple causes

Dry eye syndrome is caused by several factors, which cause inflammation of the eye surface and the lacrimal (tear) glands. This inflammation reduces the normal tear-production capacity of the glands, consequently damaging the corneo-conjunctival surface. If left untreated the damage can become self-perpetuating.

There are many things that make us more vulnerable to dry eyes:

• the environment, particularly dry heat or a windy climate or long hours in front of a computer
• disease such as diabetes, rheumatoid arthritis, lupus, scleroderma, Sjogren’s syndrome, thyroid disorders
• medications such as antihistamines, decongestants, HRT, and antidepressants
• hormonal changes
• ageing

Based on the blood test result showing better hormonal profiles, the authors of the current study conclude that “Phytoestrogen supplementation can significantly improve the signs and symptoms of dry eye syndrome in postmenopausal women”.

Nevertheless, the supplement itself addressed more than just hormone imbalance. The active ingredients in the capsules contain three substances known to address the causes of dry eye syndrome:

Alpha lipoic acid (100 mg) plays a fundamental role in the energetic metabolism of our cells. It is normally ingested with food and can be found in liver, potatoes, yeast, broccoli and spinach. As an antioxidant, it helps protect the body by fighting the damage caused by the formation of free radicals and by helping generate other important antioxidants already present in our body, such as vitamins E and C and glutathione.

Fish oil (240 mg) Adequate intake of omega-3 eicosapentaenoic acid (EPA) seems to help reduce tissue reaction and to improve lacrimal (tear) function and restore balance. Omega-3 fatty acids reduce the production of inflammation mediators, such as prostaglandins, therefore improving the irritative symptoms of the dry eye syndrome.

Plant-based phytoestrogens (200mg)  In this case from a 50% extract of fenugreek (Trigonella foenum-grecum). Rich in phytoestrogens known as furostanol saponins, fenugreek is reputed to aid the body in times of intense changes, such as during menopause or andropause (male menopause) or in particularly stressful or fatiguing periods of our lives. Fenugreek supports lipid production by the meibomian glands (which produce a specialised oil that forms the outer layer of the tear film, preventing evaporation), therefore helping retain the water component of the lacrimal film and improving the symptoms of eye dryness.

There is also evince from animal studies that fenugreek can reduce diabetes-induced cataract formation. It is also known to help improve blood sugar levels and regulate the production of cholesterol. Most recently bread made with added fenugreek flour has been suggested as a therapeutic food in cases of diabetes.

You can also include fenugreek seeds in your diet. They are very versatile and can be eaten as seeds, brewed into a tea, made into a flour and cooked as bread, or pressed into an oil.

Herbs widely used throughout history in Asian and early European cultures have received renewed attention by Western medicine in recent years. Scientists are now isolating the active compounds in many medicinal herbs and documenting their antioxidant and anti-inflammatory activities.

In a study published in the journal Investigative Ophthalmology & Visual Science, Dr Stuart A. Lipton and colleagues at Sanford-Burnham Medical Research Institute (Sanford-Burnham) report that carnosic acid, a component of the herb rosemary, promotes eye health.

Using an animal model, Lipton’s team found that carnosic acid protects retinas from degeneration and toxicity in cell culture and in rodent models of light-induced retinal damage. Their findings suggest that carnosic acid may have clinical applications for diseases affecting the outer retina, including age-related macular degeneration, the most common eye disease in the US.

Age-related macular degeneration

Age-related macular degeneration likely has many underlying causes. Yet previous studies suggest that the disease might be slowed or improved by chemicals that fight free radicals – reactive compounds related to oxygen and nitrogen that damage membranes and other cell processes.

Lipton’s team first discovered a few years ago that carnosic acid fights off free radical damage in the brain. In their latest study, the researchers initially investigated carnosic acid’s protective mechanism in laboratory cultures of retinal cells.

The researchers exposed the cells growing in the dish to hydrogen peroxide in order to induce oxidative stress, a factor thought to contribute to disease progression in eye conditions such as macular degeneration and retinitis pigmentosa.

They found that cells treated with carnosic acid triggered antioxidant enzyme production in the cells, which in turn lowered levels of reactive oxygen and nitrogen species (cell-damaging free radicals and peroxides).

Rosemary’s therapeutic potential

The researchers next tested carnosic acid in an animal model of light-induced damage to photoreceptors – the part of the eye that converts light to electrical signals, enabling visual perception. Compared to the untreated group, rodents pre-treated with carnosic acid retained a thicker outer nuclear layer in the eye, indicating that their photoreceptors were protected. The carnosic acid-treated rodents also exhibited better electroretinogram activity, a measure of healthy photoreceptor function.

So what’s next for carnosic acid?

“We’re now developing improved derivatives of carnosic acid and related compounds to protect the retina and other brain areas from a number of degenerative conditions, including age-related macular degeneration and various forms of dementia,” said Lipton.

The small study involved 29 people aged 55-85 years, in the early stages of  age-related macular degeneration (AMD). The patients, who were already showing signs of vision loss were given 20 mg of saffron a day over an average period of 14 months.

After three months all the patients showed a significant implementation retinal function resulting in an overall improvement in visual acuity. The effects, however, disappeared when patients stopped taking the saffron pills. No adverse side effects were noticed.

The study was published in the journal Evidence-Based Complementary and Alternative Medicine.

Powerful antioxidants

Saffron contains the carotenoids crocin and crocetin, which have been shown to have strong protective effects on retinal cells, helping restore function and structure of retinal cells damaged by oxidative stress and AMD.

In particular crocin has been shown to have antioxidant activity stronger than alpha-tocopherol, and can prevent eye damage from free radicals.

The earliest report on the benefits of saffron and its main active constituent crocin in treating AMD was published in 1999 and suggested that crocin and its related compounds significantly increased blood flow in the retina and choroid, and thus can prevent cell death. The authors concluded that saffron was a useful treatment in cases of ischemic retinopathy and/or age-related macular degeneration.

Protection from light damage

Constituents in saffron also protect eyes from the damaging effects of bright light, which can damage the macula. Studies show that long-term exposure to bright lights can lead to photoreceptor degeneration, and thus speed the progress of AMD.

Laboratory and animal studies, however, show that the carotenoid crocin has a protective effect against light damage, helping to maintain the healthy function of photoreceptors in the eye.

Crocetin, which is another carotenoid in saffron, has also shown promise in inhibiting photoreceptor degeneration and retinal dysfunction.

An ancient spice

Saffron is derived from derived from the flower of Crocus sativus, commonly known as the saffron crocus. It is one of the world’s most expensive spices because the stigmas of each flower need to be collected by hand and there are only a few per flower.

The carotenoid crocin is also responsible for the deep golden yellow colour that saffron imparts to food. Throughout history it has been used medicinally and as a textile dye, as well as in religious ceremonies, in flower waters, perfumes and pot-pourris, and ointments.

Ninety percent of the world’s supply of saffron comes from Iran.