N-acetylcarnosine, omega-3s, and a­ntioxidants relieve dry eyes …

Supplements that Enhance
Computer Productivity

… Are needed in the rapidly expanding world of visual display use

By Will Block

W hen you gaze at a computer screen all day long—as more and more of us are increasingly apt to do—eye secretions tend to diminish and dry up. That’s not good. In fact, this may not only cause inflammatory irritation but also diminish your reading speed and your ability to work effectively. And worse, if not addressed.1 Consequently, a new report from Japan, on the relationship between eye secretions, the growing length of time spent on computers, and the frequency of ocular symptoms, is timely.2 However, the study is devoid of suggestions about what we can do about dry eyes!

Computer Usage Dominating the World

The last few years have witnessed widespread growth in the use of personal computers, portable information terminals, and desktop devices throughout the world. This constitutes a dramatic increase in the amount of work done using visual display terminals (VDTs). One estimate places the number of individuals using the Internet as of 2012 at 2.4 billion people worldwide.3 And concurrently, the use of VDTs has surged. In fact, an increasing number of workstations have multiple VDTs. In Japan, where the new report was conducted, approximately 95 million people (80% of the Japanese population) were using the Internet by the end of 2010.2


One estimate places the number of
individuals using the Internet as of
2012 at 2.4 billion people worldwide.


Visual Display Terminal Usage Causes Dry Eye Damage


Even androids run out of tears.
In the new research report, the eyes of 96 volunteers (60 men and 36 women) were studied. All subjects were office workers who spent significant amounts of time looking at computer screens each day. They were divided according to their usage: from less than 5 hours/day (short) to between 5 and 7 hour/day (intermediate) to more than 7 hours/day (long). In the subjects, dry eye disease was diagnosed as definite, probable, or not present. Altogether, the prevalence of definite and probable dry eye disease was 9% (n = 9) and 57% (n = 55) respectively.

The researchers measured the concentration of a particular type of tear mucin* called MUC5AC, which was normalized to tear protein content and expressed as MUC5AC (nanograms) per tear protein (milligrams). MUC5AC is part of the normally occurring mucus layer that helps keep eyes moist. The differences in MUC5AC concentration between dry eye disease groups, between VDT working hours (short, intermediate, and long), and between symptomatic and asymptomatic groups were evaluated.


* Mucins are a family of high molecular weight, heavily glycosylated proteins produced by epithelial tissues in most animals, including humans. Among mucins’ key characteristics is their ability to form gels-like secretions, serving functions from lubrication to cell signalling to the formation of chemical barriers.


The Composition of Tears

Figure 1. The mechanism of tears.

LEM1408eye-diagram274.jpg
(click on thumbnail for full sized image)

Prior research has found that the aqueous layer of the tear film is composed of mucins dissolved in the lacrimal fluid and that there is not a distinct mucin layer within the tears. MUC5AC is secreted by goblet cells in the upper eyelid of the conjunctiva (See Fig. 1). As a large gel-forming mucin with extensive O-linked glycosylation (the attachment of a sugar molecule to an oxygen atom in a protein), MUC5AC is a protein that plays an important role in epithelial surface protection by cleansing the ocular surface of debris. It comprises a portion of the normally occurring mucus layer, or “tear film” that keeps the eye moist. Unless stressed. Participants with the most screen time in the study had MUC5AC levels nearing those of people with diagnosed dry eye.


Participants with the most screen
time in the study had MUC
5AC levels
nearing those of people with
diagnosed dry eye.


The More Screen Time, More Exposure, the Less Mucin

“To understand patients’ eye strain, which is one of [the] major symptoms of dry eye disease, it is important that [the] ophthalmologist pay attention to MUC5AC concentration in tears,” said Dr. Yuichi Uchino, the lead author of the new study.4 Uchino is an ophthalmologist at the School of Medicine at Keio University in Tokyo. In his email interview with Reuters Health4 Uchino went on to explain that reading from a computer screen decreases blinking times, compared to reading from a book. Also, staring at screens tends to open eyelids wider than while doing other tasks, thus exposing more surface area. That, in addition to infrequent blinking accelerates tear evaporation and is associated with dry eye disease.


Twice as many women
were vulnerable to dry eyes,
compared to men.


Furthermore, MUC5AC concentration is decreased on the ocular surface, and the wettability of the epithelium is impaired. That’s because the secreted mucins are hydrophilic in nature, a characteristic emanating from their heavy glycosylation which helps to hold fluids on epithelial surfaces.

More Woman than Men Susceptible to Dry Eyes

When the results were tallied, 7 percent of men and 14 percent of women were diagnosed with dry eye disease, meaning they reported symptoms of eye problems like irritation, burning or blurred vision and had poor quality or quantity of tear film, according to the tests. Twice as many women were vulnerable to dry eyes, compared to men.

MUC5AC is a Determinant of Dry Eyes

The mean concentration of MUC5AC was 6.8 ng/mg in 192 eyes (96 * 2). The mean MUC5AC concentration was 6.9 ng/mg in men (n = 120) and 6.7 ng/mg in women (n = 72). Thus there was no significant difference in mean MUC5AC concentration between men and women. However, those with definite dry eye disease had an average of 3.5 ng/mg of visual display terminal compared to 8.2 ng/mg for people without the disease.

“Mucin is one of the most important components of the tear film,” said Dr. Yuichi Hori, who was not a part of the new study. “Mucins (like MUC5AC) function to hold water on the ocular surface of the epithelia that synthesize them, hence, they are major players in maintenance of the tear film on the ocular surface,” Hori told Reuters Health by email.4

In an earlier study done by the same researchers, annual dry eye disease productivity losses were estimated to be $6,160 per employee when measured by total production.5 MUC5AC was not measured in that study. It is also worth noting the dry eye disease is age-related with a prevalence approaching 34% in the elderly.6 Other studies indicate that diabetes may also predispose individuals for dry eyes.7

Eye Drops as the First Solution

According to Market Scope,8 approximately 19 million people in the United States have dry eye disease, including approximately seven million people who suffer from the moderate to severe form of dry eye disease, and many of these are undoubtedly computer related.

Dry eye may be chronic for some but can be managed with over-the-counter (OTC) or prescription eyedrops. The moisturizing ingredients of eyedrops, especially hydroxypropyl-methylcellulose (aka hypromellose) and glycerin, are effective by themselves in reducing the symptoms of dry eye.9,10 Prescription drugs and some OTCs are double-edged swords however. Topical cyclosporin, for example, may increase tear production, but has been associated with increased risk for cancer.

Diminished Productivity and Increased Depression

Subjects diagnosed with dry eye disease tended to be less productive and are more likely to be depressed, according to previous studies. In a Polish study, the correspondence between depression and dry eye syndrome was 70%.11 In another study conducted in China, an elderly population from Beijing had a clear association between depression and dry eye disease and symptoms.12

Humidifier Implementation

It is also important to control your environment. If your work area or any area in which you work or live is dry and drafty, or filled with smoke or dust, it is wise to make changes by using humidifiers and filters. You might also want to avoid the use of dryers, heaters, air conditioners or fans, especially when these devices are directed toward the eyes.


The moisturizing ingredients of
eyedrops, especially hydroxypropyl-
methylcellulose (aka hypromellose)
and glycerin, are effective by
themselves in reducing
the symptoms of dry eye.


N-Acetylcarnosine Eyedrops

A well-known cataract researcher has stated that an N-acetylcarnosine eyedrops formulation (which he designed to alleviate lens-clouding cataracts) can help resolve dry eye problems. However, he cites no evidence in any of his papers to support his claims regarding dry eyes.13 If N-acetylcarnosine does help relieve dry eyes, it is probably due to the effect of carnosine to deaggregate a type of protein known as crystallins, which tend to suffer degradation through glycation (see “Fighting Cataracts with N-Acetylcarnosine” in the April, 2006 issue). One form of crystalline, α-crystallin, occurs primarily in the lens of the eye, where glycation results in opacity, which in turn contributes to cataractogenesis. Anti-glycation compounds such as those containing carnosine may be preventive, and indeed, carnosine reverses lens opacity in human trials. The mechanism for this observation may involve carnosine’s ability to disaggregate glycated protein.14

Another form of crystallin (αB-crystallin) is found in the lacrimal gland and tear fluid and the possible ability of L-carnosine to quench this may also help reduce dry eye.15 Strong anecdotal evidence indicates that this may be valid, but to date no scientific data are available. However, there are some data showing that cataracts and dry eye syndrome are associated, as are other age-related ocular problems such as macular degeneration, glaucoma, and diabetic retinopathy.

Omega-3 Fatty Acids and Antioxidant Consumption

Supplementing your diet with fish containing high levels of dietary omega-3 fatty acids is associated with a decreased incidence of dry eye syndrome in women.16 In another study,17 dietary supplementation with a combination of omega-3 essential fatty acids and antioxidants was found to be an effective treatment for dry eye. A total of 905 patients (72% women, median age 60 years) with dry eye syndrome and using artificial tears (moisturizing eyedrops) to relieve symptoms participated in an open-label intervention study.


Quenching a crystallin found in
the lachrymal gland with
N-acetylcarnosine may also
help reduce dry eye.


The subjects took three capsules/day of the nutraceutical formulation, each containing 500 mg of omega-3 fatty acids (1500 total/day) for 12 weeks. Also in the capsules were 50% of the RDAs for vitamin A, zinc, copper, manganese, and selenium, and 100% of the RDAs for vitamin C and Vitamin E. In all likelihood, these are not significant amounts.

The dry eye symptoms included scratchy and stinging sensation in the eyes, eye redness, grittiness, painful eyes, tired eyes, grating sensation, and blurry vision.


Dietary supplementation with a
combination of omega-3 essential
fatty acids and antioxidants
was found to be an effective
treatment for dry eye.


At the end of the study, all individual symptoms improved significantly. Also, there was a decrease in the percentage of patients in which dry eye symptoms predominated nearly all the time (53.5% versus 34.1%). 68.1% of the subjects reported better tolerance to contact lenses after treatment. The mean number of daily instillations of artificial tears also decreased significantly. Side effects were either minimal or nonexistent (70%).

In another study, using the nutrients vitamins A, C, E, B1, B2, B6, folate, zinc, β-carotene, lycopene from tomato, and polyphenols from grape marc, 24 subjects diagnosed with dry eye syndrome were randomized in a crossover double blind trial to receive either the antioxidant combination or placebo. Ocular symptoms (sore eyes, burning, itching, sensation of foreign object in the eye, photophobia, sticky eyes, and redness), visual comfort, and general well-being were evaluated weekly.

After 12 weeks of supplementation with the antioxidant combination, significant improvements were observed such as reduced burning, itching, sensation of foreign body in the eye, and redness. These results demonstrated that supplementation with oral antioxidants can improve tear stability and quantity, and also subjective clinical signs.

Whose Vision is It Anyway?

If you read this publication only in paper form and don’t use a computer you have less to worry about. But if you’re “spinning” at your computer for long hours, you might want to look carefully at what can be done to prevent a big loss to your visual efficacy. N-acetylcarnosine eyedrops containing moisturizers, along with omega-3 and antioxidant supplementation, and an improved humidification and working environment could go a long way to help prevent dry eye syndrome and maintain your productive relationship with your computers.

References

  1. Ridder WH 3rd, Zhang Y, Huang JF. Evaluation of reading speed and contrast sensitivity in dry eye disease. Optom Vis Sci. 2013 Jan;90(1):37-44.
  2. Uchino Y, Uchino M, Yokoi N, et al. Alteration of Tear Mucin 5AC in Office Workers Using Visual Display Terminals: The Osaka Study. JAMA Ophthalmol. 2014 Jun 5. doi: 10.1001/jamaophthalmol.2014.1008. [Epub ahead of print]
  3. Group MM. World Internet usage and population statistics. June 30, 2012. http://www.internetworldstats.com/stats.htm. Accessed June 20, 2014.
  4. Doyle C. Staring at screens all day linked to changes in eye secretions. Reuters Health. http://uk.mobile.reuters.com/article/healthNews/idUKKBN0ER2HG20140616. Published: June 16, 2014. Accessed: June 21, 2014.
  5. Uchino M, Uchino Y, Dogru M, Kawashima M, Yokoi N, Komuro A, Sonomura Y, Kato H, Kinoshita S, Schaumberg DA, Tsubota K. Dry eye disease and work productivity loss in visual display users: the Osaka study. Am J Ophthalmol. 2014 Feb;157(2):294-300.
  6. Lin PY, Cheng CY, Hsu WM, Tsai SY, Lin MW, Liu JH, Chou P. Association between symptoms and signs of dry eye among an elderly Chinese population in Taiwan: the Shihpai Eye Study. Invest Ophthalmol Vis Sci. 2005 May;46(5):1593-8.
  7. Kaiserman I, Kaiserman N, Nakar S, Vinker S. Dry eye in diabetic patients. Am J Ophthalmol. 2005;139(3):498–503.
  8. Eleven Biotherapeutics. Opthalmalic Disease. http://www.elevenbio.com/pipeline/ophthalmic.html. Accessed June 21, 2014.
  9. Doughty MJ, Glavin S. Efficacy of different dry eye treatments with artificial tears or ocular lubricants: a systematic review. Ophthalmic Physiol Opt. 2009 Nov;29(6):573-83.
  10. Tauber J. Efficacy, tolerability and comfort of a 0.3% hypromellose gel ophthalmic lubricant in the treatment of patients with moderate to severe dry eye syndrome. Curr Med Res Opin. 2007 Nov;23(11):2629-36.
  11. Mrugacz M, Ostrowska L, Łazarczyk-Kirejczyk J, Bryl A, Mrugacz G, Stefa´ńska E, Szulc A. Dry eye disease in patients treated with antidepressants. Klin Oczna. 2013;115(2):111-4.
  12. Labbé A, Wang YX, Jie Y, Baudouin C, Jonas JB, Xu L. Dry eye disease, dry eye symptoms and depression: the Beijing Eye Study. Br J Ophthalmol. 2013 Nov;97(11):1399-403.
  13. Babizhayev MA. Potentiation of intraocular absorption and drug metabolism of N-acetylcarnosine lubricant eye drops: drug interaction with sight threatening lipid peroxides in the treatment for age-related eye diseases. Drug Metabol Drug Interact. 2009;24(2-4):275-323.
  14. Seidler NW, Yeargans GS, Morgan TG. Carnosine disaggregates glycated α-crystallin: an in vitro study. Arch Biochem Biophys. 2004;427:110-5.
  15. May CA, Welge-Lüssen U, Jünemann A, Bloemendal H, Lütjen-Drecoll E. AlphaB-crystallin in lacrimal gland duct and tears. Curr Eye Res. 2000 Jul;21(1):588-94.
  16. Miljanović B, Trivedi KA, Dana MR, Gilbard JP, Buring JE, Schaumberg DA. Relation between dietary n-3 and n-6 fatty acids and clinically diagnosed dry eye syndrome in women. Am J Clin Nutr. 2005 Oct;82(4):887-93.
  17. Oleñik A. Effectiveness and tolerability of dietary supplementation with a combination of omega-3 polyunsaturated fatty acids and antioxidants in the treatment of dry eye symptoms: results of a prospective study. Clin Ophthalmol. 2014;8:169-76.


Will Block is the publisher and editorial director of Life Enhancement magazine.

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