artical:A better faux teardrop

[sazy123]

Well rounded artical addressing different treatments, future treatments etc.

http://www.latimes.com/features/heal...adlines-health

[Brighteyes]

a better faux teardrop

Here is the article in full:

A Better Faux Teardrop
By Karen Ravn
February 12, 2007

Dry eyes afflict millions. Scientists are cooking up new eyedrops to better match nature.

To most of us, tears are those wet, salty drops that come out of our eyes when we cry. To scientists who study them, they're those wet, salty, oily, mucous, protein-filled drops that lubricate our eyes and protect them from dust, debris and infection.

For the most part, tears go unnoticed — until something goes wrong. Eyes sting, burn, itch or turn red. They feel like they're full of sand or being poked with a stick.

These symptoms, grouped under the general label "dry eye," can develop when a person doesn't make enough tears, when tears evaporate too fast, or their intricate chemical balance is knocked out of kilter.

Scientists are working to find more — and more effective — approaches to treating the problem. Several new products have entered the market in recent years and are jockeying for position with older remedies, sometimes with only unpublished trials to support them. More strategies are under development.

The task is tricky, because tears are more complex than pure water. The lacrimal glands, just below the eyebrow, produce them continuously. Salty water forms the middle — aqueous — layer of a three-layered tear film that lubricates and protects our eyes.

Below it lies the sticky mucous layer, secreted by the conjunctiva, a transparent membrane covering the surface of the eyeball. Mucus "glues" the film in place. Third is the lipid, or oily, layer produced by tiny sebaceous glands, the meibomians, lined up along the edges of the eyelids. The lipids get squirted onto the eye surface when we blink, and float on the top of the aqueous layer, like oil on a puddle, minimizing evaporation.

The tear film is constantly being renewed. The old batch drains out into our nose and throat through tiny holes called puncta, and the eyelids spread a new batch smoothly and evenly across the surface of our eyes. This happens every time we blink — and we blink 12,000 to 15,000 times a day.

There are many causes of dry eye, including an autoimmune disease called Sjögren's syndrome that attacks the tear-producing glands of the eye, side effects of Lasik surgery, taking antihistamines or spending too much time at a computer. Women and older people are most prone.

Experts estimate that 20 million Americans have mild symptoms, while for 6 million women and 3 million men, the symptoms are moderate to severe.

"Our aging population of baby boomers is resulting in a very significant increase in the number of people who suffer from dry eye," says Doug MacHatton, vice president investor relations and strategic communications for Alcon Laboratories in Fort Worth.

Because dry eye is becoming more prevalent, over-the-counter treatments are big business and getting bigger.

Among the recent entrants into the market is Optive, introduced in January, designed to fight the problem of over-salty tears. It contains two key ingredients in addition to water — carboxymethylcellulose, a lubricant with a unique binding effect, and glycerin, which helps keep the eye hydrated.

"The glycerin goes into cells, takes water with it and keeps it there," says Joe Vehige, Allergan's senior director of consumer eye care research and development. In an unpublished, 90-day study of about 300 subjects with dry eye symptoms, he says, Optive outperformed two other popular artificial tear products: Refresh, also made by Allergan, and Systane, made by Alcon. Performance was measured on six common measures, including needed frequency of use and comfort rating. MacHatton's company's product, Systane, introduced in 2003, improves comfort by increasing lubrication between the eyelid and the cornea. It does so by combining a substance called hydroxypropol guar (HP-Guar), a gelling agent that works to hold Systane on the eye surface, with polyethylene glycol 400 and propylene glycol, two lubricants.

Kim Fisher, Alcon's senior product manager for dry eye, says that several controlled, double-blind studies have shown that Systane outperforms other solutions on four of the main patient symptoms — namely, burning, dryness, grittiness and the feeling that something is in the eye.

New developments came also from a better understanding of what happens to eyes when they're dry. In the late 1980s, Stephen Pflugfelder, professor and director of the ocular surface center in the department of ophthalmology at Baylor College of Medicine in Houston, discovered high levels of inflammatory mediators in the tear film of dry eye patients — chemicals, that is, involved in the inflammation process. One of the first he identified was Interleukin-1, part of the body's response in fighting infection.

"This showed there was inflammation going on in dry eye," Pflugfelder says. Indeed, scientists now believe that dry eye can be caused by inflammation of the lacrimal and meibomian glands, resulting, respectively, in insufficient tear production or too much tear evaporation. Three treatments intended to fight inflammation have either come on the market recently or are in clinical trials.

One is Restasis, introduced by Irvine-based Allergan Inc., in 2003. It contains the anti-inflammatory chemical cyclosporine. Restasis has been shown in clinical trials to increase tear production and is the only prescription eye drop approved by the Food and Drug Administration for that purpose.

More than 4 million prescriptions for Restasis have been written so far. It is most effective in treating chronic dry eye early in the disease, Vehige says.

Also in 2003, a company called Advanced Vision Research, makers of an older dry eye remedy called TheraTears, introduced TheraTears Nutrition, an oral supplement designed, like Restasis, to counter inflammation, but with all-natural ingredients that didn't require FDA approval.

TheraTears Nutrition is a blend of vitamin E with flaxseed oil and fish oil — providing short- and long-chain omega-3 fatty acids, respectively, says Jeffrey Gilbard,, a clinical assistant professor at the Harvard Medical School, director of the Dry Eye Clinic at the New England Eye Center, and founder and chief scientific officer of Advanced Vision.

His studies, he says, have shown that short-chain omega-3s thicken the oily layer of the tear film, but do not suppress inflammation, while long-chains do the opposite. At an upcoming meeting of the Assn. for Research in Vision and Ophthalmology in May, Athena Papas, professor of dental research at Tufts University, says she will present evidence that TheraTears Nutrition makes patients with dry eye (and dry mouth) feel significantly better.

David Sullivan, a senior scientist the Schepens Eye Research Institute and an associate professor of ophthalmology at Harvard Medical School, is attacking inflammation with still a different weapon: hormones. He originally hypothesized a connection between dry eye and hormones because dry eye is much more common in women, and because the occurrence of dry eye goes up as people get older — as the production of the sex hormones estrogen and androgen is going down.

Sullivan has studied the effects of both estrogen and androgen on dry eye. Perhaps surprisingly, he found that upping estrogen levels may actually make dry eye worse. But he has found that topical treatment with androgen suppresses inflammation in both the lacrimal and meibomian glands in patients with Sjögren's syndrome.

Researchers in Italy have shown that androgen has a positive effect on the mucous layer too, he says. Androgen drops are currently in a second round of clinical trials at Allergan.

Researchers at Alcon have been developing a very different product, based on a "mucin secretagogue," a substance that increases the secretion of a particular mucin. MacHatton says initial test results were good, but they haven't yet been able to prove its effectiveness in clinical trials.

As a dry eye patient himself, MacHatton notes that there's something unpredictable about the phenomenon of dry eye that may make the perfect remedy hard to pin down.

Although he believes that Systane is the best artificial tears product, he says, "There are times when I'm using it, and it's just wonderful. There are other times when it's not."

Answers may lie inside tears

In hopes of improving their abilities to diagnose disorders, as well as eyedrops and other treatments available to patients, scientists are studying the composition of tears. They're trying to figure out what healthy tears are made of so they'll have a baseline for comparison with tears from patients with eye diseases and find biomarkers, substances whose presence or absence can help in making better, earlier diagnoses.

Researchers studying all three layers of the tear film are making progress.

A team led by Kelly Nichols, associate professor at Ohio State University's College of Optometry, recently discovered a new class of lipids, fatty acid amides, in the lipid layer of the tear film. The study, published in the current issue of Investigative Ophthalmology & Visual Science, identifies one of the fatty acid amides, oleamide, as a dominant presence. Oleamide plays important roles in the central nervous system. No one knows what it's doing in tears.

The tear's mucous layer is so important that someday it could improve the classification scheme for various types of dry eye, says Darlene Dartt, senior scientist and director of scientific affairs at the Schepens Eye Research Institute and associate professor at Harvard Medical School. Scientists now know there are several kinds of mucins at the surface of the eye. All are sugary and attract and hold water, which is why the tear film sticks to them instead of falling out of our eyes. Some are "tethered" to the surface of the eye. Others drift around.

The tear's aqueous layer is mostly water, but it's also full of electrolytes (salts that can conduct electricity) and proteins. Many of the proteins are antibacterial, including lysozyme, lipocalin and lactoferrin. Down the road, Ohio State researcher Kari Green-Church sees bigger possibilities for proteins in tears. The time may come when they can be used for diagnostic tests that now require a needle. "I know my kids would much rather have tears collected than blood," she says.

[brd888]

.....identifies one of the fatty acid amides, oleamide, as a dominant presence. Oleamide plays important roles in the central nervous system. No one knows what it's doing in tears.

Maybe someone should try and find out!
This article is quite fascinating.

Regards

[Rojzen]

echoing

Indeed, brd888. . .The basic-research observations are fascinating, but they so often dead end before being connected to some therapy. . .I am myself a patient at the Ohio State Optometry Clinic, and while I get really excellent care and doctor-commitment there, I have yet to detect any pourover of the research going on there in to clinical practice. It all boils down to funding, I suppose.

Dr. Nichols has discovered this mysterious oleamide, but now, to my knowledge, she has funding only to conduct a relatively unrelated, nontherapeutic study on the particular features of dry eye in postmenopausal women. The simpleton in me asks why NIH has not, instead, funded a study on how to develop oleamide replacements, or on what the exact functions of oleamides are. . .I have to assume that Dr. Nichols attempted to move in these directions, but, instead, received funding for yet another epidemiological study that confirms our suffering without doing anything about it (:^). . .

Anyway, things could be worse, right? At least we have researchers interested in what ails us. . .

[brd888]

Rojzen,
Yeah I agree. I could go on at length about this subject. I suppose at school I wanted a career in scientific research such as this but for practical reasons I decided on engineering.

I suppose the reason NIH funded the research in postmenopausal women is because this group is the largest dry eye group of patients. Also I think funding-research-project process is a science in itself!

At least with the internet we (and prof researchers) have instant access to global information on the subject. Imagine doing this in a 1990's Library! It is amazing how much science there is on the subject of the tear film yet onlly such basic treatment for dry eye syndrome. I guess it is easy to identify compounds in the tear film but difficult to quantify their role, if any. For instance, Oleamide has been discovered in the tear film but how can we know it's exact function? Maybe it has no function in the tear film?

I will leave it at that for now.

Regards,
Bruce