We got to the last part of three articles about dry eye (here’s part one and two). We know the causes and symptoms, but: how do we fix it?. Already ahead in the first article of the series that treatment is often unsatisfactory until the patient is made to the idea of their disease. Virtually no curative treatment, dry eye is a chronic disease (except for very specific cases such as dry eye secondary to laser surgery of the cornea).
Artificial Tears
We can say that is the treatment. In most cases, is the only treatment, and it is certainly the most important. Not address the causes of dry eyes (which would be ideal), with the mechanism of the disease. Being positive, at least act on the disease itself and braking when using the treatment (if we treated only the symptoms would be worse because only “mask the disease.”
In other words: for whatever reason, the tear is insufficient or of poor quality, or not replaced sufficiently with the flicker (see, without wanting to leave me just another simple definition of dry eye). With treatment, natural tears are still producing the same, but the mix with tears artificially created, which is basically water with one or more active ingredients. Overall, the components of artificial tears have to provide the following features.
Viscosity. We talked about the chemical has an affinity for water and retained on the surface of the eye, slowing evaporation and removal by the lacrimal system. The viscosity grade can separate itself tears, “more liquid” or “heavy” to use colloquial terms.
The more viscous tears, lasts longer in the eye, making it more useful in cases of dry important. On the other hand, a thick tear a thin membrane is not totally transparent, but something that resembles a gel or ointment, so it causes blurred vision. And also, that sensation of thickness on the eye is uncomfortable for some people.
By contrast, a low-viscosity tear is very comfortable and does not cause blurred vision, but is short in the eye. After a few blinks, artificial tears creeping into the lacrimal system and lose effectiveness. An extreme example of “liquid tears” would use the saline solution sold in pharmacies (used for ocular and nasal washes, for example). The saline solution is simply salt water (NaCl) at a concentration of 0.9% which has an osmotic pressure similar to the tear or blood (after talking about this osmotic pressure). It has an active ingredient that retains water on the eye, so that in a minute and almost nothing remains in the eye serum. The feeling is cool, sure, but for dry eye treatment is much lower than the real tears, aspiring to be in the eye 20 to 40 minutes. The use of saline solution (other than to wash the eye) would be appropriate only for mild dry eye.
The laboratory now pursuing is to get tears of intermediate viscosity, taking advantage of the thick liquid and tears, without the drawbacks. Viscous enough to hold some time in the eye, and to use them 4-6 times a day is sufficient for good coverage. And liquid enough to not cause blurred vision and foreign body sensation.
Resemblance to natural tears. We need to get a chemical similarity with the tear film of the eye itself. The tear makes a function of nutrition and essential maintenance and very complex to the cells of the eye’s surface. It is very important to obtain an osmotic pressure (the overall concentration of substances dissolved in water) similar to the natural film, and it also helps that it looks like in terms of the amount of each chemical element (mainly ions). Indeed, even some tears are struggling (and so promoted) in providing some ions with a ratio close to tears (sodium, potassium, phosphate, zinc, etc), there really is a series of more complex compounds that are impossible at the moment imitate (antibodies, enzymes, growth factors, nutrients, etc). In this line, to provide other items to maintain healthy eye surface (and help regeneration), we autologous serum, discussed later.
Sterility: Artificial tears can be a breeding ground for germs, and be counterproductive to lie on the eye drops colonized by microbes.
Formerly, all the tears were marketed in the form of drops, ie, a boat where there are enough drops for several days or weeks, in addition to water and active ingredient, contains a preservative to prevent the colonized (much) by bacteria, fungi and so on. Eye drops are comfortable, because you carry enough dose to not scarce. But preservatives are hard on the surface of the eye, especially when you consider that dry eye suffers more the toxicity of these chemicals. They are Eye Secrets treatments that are often chronic and sometimes take a day more than other standard treatments (glaucoma, conjunctivitis, etc.).
Most of the art artificial tears are preservative free, thus avoiding the toxic effect. Therefore, I am that you have to choose when to use many times a day. There are several ways to avoid the preservatives, the most common is using the format unidosis. Each “blister” contains a few drops, which serves to once or twice (rarely reaches three shots). I must say that although we should not tear unidosis more than 6-8 hours to leave open, in 2-3 hours is not enough time to be colonized dangerously. Therefore, in patients who are many times a day with tears, can close the container for the next time. In fact, some tears and have designed the cap can be opened to replace.
In addition to the single-dose containers (or dose), there is a tear that comes in a form of eye drops apparently, without preservatives. The trick is in a micro system that keeps out germs. The idea is interesting because it gains in comfort, but they are expensive and tears do not fall within the public health system recipe (or medical societies). So there’s an economic problem when using them.
Other properties: There is much competition from pharmaceutical companies in this sector of dry eye, and investigated enough. So tears are appearing different specific properties, where each one wants to make a difference. Some highlights tear mucomimética property, ie property that mimics the mucin of the tear. Therefore, this tear theoretically “stick” more to the eye. Another offers a lipid layer, mimicking the fatty layer of the tear film. Another viscosity varies dynamically based on certain characteristics of the surface of the eye, such as pH. But despite all innovations are, the reality is that the most important parameters of a good tear remain: to ensure sterility, with a suitable viscosity, and with enough similarity to natural tears.
Treating the cause
It is theoretically ideal: treat the cause of dry eye, and so cure the disease. Unfortunately, it is exceptional that we can do. Typically, the patient can offer little more than artificial tears. And these, not treat the cause, not cure dry eye. Alleviate the problem while the treatment is used often enough (and usually several times a day, every day). Mild dry eyes (in young people, by the computer, for example) go well with tears, because due to the lightness of the frame, with putting a tear from time to time is sufficient. But dry eyes “real” requires continued treatment, a strong will, and the patient feels (true, by the way) that is all pending on artificial tears.
The problem, as I say, is that we can hardly treat the cause. Dry eye of a certain intensity usually found in older people, due to the gradual deterioration of the tear glands. These glands are lost gradually, and can not regenerate, whatever we do, there is no treatment to remove years. There are several factors mainly related hormone, which is why there are more dry eye in women. Nor can we address these causes.
A common cause of dry eye, as we mentioned in previous articles in the series, blepharitis. This altered secretion glands of the eyelid margin can be treated. In young people themselves which is often dry eye is due (in part at least) to this blepharitis. So if we treat the problem, you can reduce (or eliminate) the use of artificial tears. But the treatment of blepharitis is not addressed either to the cause of it, so the problem is controlled, but not eliminated. So you also have to make the treatment of blepharitis, more or less continuously.
But we have said that the cause of dry eye is multifactorial: that is, there are many factors that favor it. Although the most important cause we can not treat, there are other aspects that we can intervene: environmental factors. Avoid drafts, using a humidifier to your home or work, pausing when you are exercising intensely viewed. These measures are not taken much into account when the doctor mentioned (more weight is still a recipe for a recommendation on the habits of routine life), but the truth is they can offer a great improvement to patients.
Other treatments
For the dry eye has been investigating for some time, and continue to devote much effort to find better solutions, so there have been numerous treatments. Let me mention a couple of them have shown good efficacy and are used routinely. Highlight several things: although they sound very new and good, none is a panacea or cure dry eye. None replaces artificial tears, which are the mainstay of treatment. Therefore, the subjects viewed these novel treatments as a way to get rid of artificial tears is a mistake. More importantly: the indications for these treatments are specific and must always be evaluated by an ophthalmologist and only by him. Just as the use of tears can be done more quietly (tears, especially those with no preservatives, no side effects), treatment will not be. Therefore, the above mentioned to explain its operation. But any reader with dry eye that is looking for alternatives to artificial tears, which do not look here. The indication must always do the ophthalmologist.
Punctal plugs. Involves placing a small plug especially in the lower punctum. Thus, just tear escapes from the lachrymal. Since we have a little tear or evaporates quickly, at least, that we are aware there by natural means. The advantage of earplugs is that it’s reversible: when there is no need or cause any problems, you can re-retire. Does not fit all dry eyes. In some cases of dry, there is what is called (not very technically) “teardrop sick.” An example of this are autoimmune diseases that cause dry eye: tear accumulate in the inflammatory elements that irritate the eye and alter their own tears. In this case, these products accumulate in the eye and are eliminated naturally, is counterproductive.
Autologous serum. It’s about making a kind of eye drops of blood serum from the patient (obtained by drawing blood and removing the cells). Let the water of this serum is enriched with nutrients and growth factors that stimulate cell regeneration. As some of the patient, it is impossible to produce rejection. Not only is used in dry eye, but in a variety of ocular surface diseases, for the very large capacity for regeneration. The form of conservation and use of autologous serum is quite cumbersome (must always be refrigerated, each little container lasts a short time, can not be exposed to light, etc). We also have to be careful because it is a breeding ground for bacteria. And in some patients produces a foreign body sensation and discomfort. Only indicated in severe cases, not continuously but as short courses, but the improvement is noticeable in most cases. Needless to say, it is an expensive treatment.
