Vision correction - See what's new

The correction of the vision has come a long way from the décimotercero century in which the first pair of spectacles was made nailing together the handles of two lenses that magnified. Today, the surgical progresses in the correction of the vision, as well as advances in eyeglasses and traditional contact lenses, can potentially improve the vision of a person to improve that the optimal range of "20/20." It is not no surprise, later, that the employee of people on crystals or the contact lenses is visiting his specialists of the eye-care, hoping to find a fast adjustment for some historical problems of the vision between the arsenal of new techniques, products and technologies. Learning on some of the common disorders that they can threaten the vision and how the eye "sees" can help to determine the best treatment him to correct its vision. It is also important to understand the advantages, the disadvantages, and the limitations that come with procedures and aids from the correction from the vision. How the eye sees Have 20/20 vision means to see in 20 feet one what person with the normal vision sees in 20 feet. A person who has 20/40 vision can see in 20 feet which sees the person with the normal vision in 40 feet. Et cetera. The eye "really does not see" objects. In place, it sees the light that the objects reflect. In order to consider clearly, the light that presses the eye must double or "refract" through the cornea -- the clear window in the front of the eye that it provides most of the energy that focuses. The then light travels through the lens, where fine- it tempers to be centered correctly in the layer of the nerve that aligns the posteriora part of the eye -- the retina -- and sent to the brain via the optical nerve. The retina acts like the film in a camera, and the clear vision is only reached if the light of an object is centered exact in her. If no, the image is guarded that you see. This is called a refracting error. The refracting errors happen generally in healthy eyes of another way. They are caused mainly by an ocular globe, a cornea or a formed imperfect lens. There are four basic types of errors: Myopia or nearsightedness -- the near objects appear acute but those in the distance are guarded. The ocular globe is longer than normal of the front to move backwards, images enfoqúese so in front of the retina in time in of her. Hyperopia or farsightedness -- the distant objects can be considered clearly but the objects for above close are guarded. The ocular globe is shorter than normal, the images focus so behind the retina. The astigmatism -- the objects are guarded in any distance. The cornea, the lens, or the both not to be shrewdly centered images in the retina form. Eye of presbyopia or the aging -- the eye loses its capacity to change the center due to the natural process of the aging. This happens generally between 50, ages 40 and connection to wish description the crystals, the contact lenses, and the attempt of the surgery of the eye of the laser to reduce refracting errors making rays light is centered correctly in the retina. Surgery Of the Eye Of the Laser -- a Popular Alternative the surgery of the eye of the laser thinks for the people who wish to reduce to the minimum her dependency on crystals or the contact lenses. The surgery of the laser can provide the correction of the vision similar to what would be obtained with crystals or the contact lenses. People under impression that the surgery can improve its vision beyond which he can see with crystals or the contact lenses, nevertheless, will be probably disappointed. To a great extent, the greatest increase of the interest of the surgery of the eye of the laser has recently been in a called procedure "keratomileusis in situ of the laser," popular well-known like LASIK. The publicity for this technique appears prominent in the plugs of the diffusion, including the Internet and in newspapers and compartments. Luckyly, it says that Terrence P. ÓBrien, M.D., spokesman for the American academy of ophtalmology (AAO), most of the surgeons and of the medical centers it is making a good work educate to the public on the risks and the advantages of LASIK. "only the patients need to be informed in advance very well," he says. LASIK permanently changes the form of the cornea, and it is made for the degrees that vary of nearsightedness, of farsightedness, and the astigmatism. A surgical knife, call microkeratome, is used to cut to a fin in the cornea, leaving a hinge in an end of the fin. The then fin bends again to reveals the average layer of the cornea, call the weave connector. The pulses of a laser controlled by computer of excimer vaporize a portion of the weave connector and the then fin is replaced. Clearing this fine weave, the form of the central cornea is changed, and the refracting error is reduced. ÓBrien, that is also director of the refracting surgery in the institute of the eye of Wilmer in the university of Johns Hopkins in Baltimore, has been made on 10,000 surgeries of the eye. However, he notices that the people who consider LASIK need to be careful ads that makes promises excessive. the "price does not have to be the first factor" in the consideration to have delicate surgery of the eye, he says. "the blindness populates secondly with the fear only to the cancer, and just then they would not consider a discount operation of the heart or opened surgery of the brain of the budget, they do not have to take an occasion with its eyes." The true fight, he says, is in doctors of the training. "the technology more outpost and the exact will of the laser give poor results if you do not have an experienced surgeon, able." This last big drum on the ahora-más-comprable advantage of LASIK, joined with some pretty attractive results, makes surgery one of the most exciting options of the correction of the vision available. The doctors say that LASIK gives a fast visual recovery, with minimum pain, and little or anything of postoperating malaise. In fact, most of the people who experience LASIK, as Beth Polazzo -- one of the patients of ÓBrien -- can see to lead well enough immediately after surgery, and has generally excellent vision within one week. "it had good vision immediately," says 54-year-old Brooklyn, N.Y., resident, although an eye had to be possible retired officer. "this one is the best one than I have seen since it was seven years as an older person." The laser makes its work on each eye in less than a minute, and the patients are typically again to work or normal activities in the term of three days. Whereas most of people he is satisfied with the results of his surgery, ÓBrien says that, like with any medical procedure, there are implied risks. Some include: excessive or underneath-treatment; the incapacity to use the contact lenses; permanent loss of vision; reduction in the quality of the vision including the development of the fulgor, the halos, and starbursts; difficulty with night-leading; and vision reduced in déviles conditions of the illumination. The risks bend when both eyes treat in the same time. Also, LASIK is not reversible. That one is porqué in the case of Polazzo, ÓBrien undercorrected intentionally its eye of the distance. "we aimed for monovision modified," he we explained, who means that an eye would close see for above whereas the other would be corrected to see distances. But Polazzo experienced a certain regression in its eye of the distance -- that is to say, its vision of the distance began to get worse whereas it returned to nearsightedness -- some weeks that followed surgery. Nevertheless, due to undercorrection initial, ÓBrien it could fix the problem. To Ralph Rosenthal, M.D., director of the division of the administration of the food and the drug of the oftálmicos devices and the ear, the nose and the throat in the center for the devices and the radiological health, say that nobody knows the effects long term of the surgery of the eye of the laser. "just we cannot still know that," he says, so when people call to look for a guarantee in the years for the success of the procedure, "I cannot give one them." Before LASIK that experiments, Rosenthal says that people must weigh the risks carefully and the advantages based on which is important for him, and potential the indirect effect, including the pros and the con of doing or ambo eyes to do ignition the same day. It is also important to avoid of being influenced by the friends who have had surgery or doctors of LASIK that animate to patients who do so. A second procedure of the laser today used as an alternative to LASIK is keratectomy photorefractive, or PRK. Although ÓBrien says that less than 5 percents of people they experience PRK, continues being the procedure of the option for certain conditions of the eye. This type of refracting surgery form again smoothly the cornea by microscopic amounts that they clear of fine weave of the external surface with a fresh beam of ultraviolet light, controlled by computer, nevertheless, does not imply cutting. The procedure takes only some minutes, and the patients are typically again to daily routines in five to seven days. The clinical studies indicate that near 5 percents of containers of PRK they continued needing crystals for the vision the distance that followed the surgery, and crystals of the necessity of up to 15 percents once in a while, for example when leading. In addition, many populate the experienced smooth corneous haze after the surgery, that is part of the normal curativo process. The haze appeared to have little or nothing of effect in the final vision, and it was possible to be only considered by a doctor underneath a microscope. It stops near 5 percents of patients of PRK, the vision good-corrected without the corrective lenses slightly worse era after surgery than before. These conditions, nevertheless, improved or disappeared in most of people in six months. Another new one, less-invader procedure of the laser -- indicated temporarily to reduce hyperopia -- is directing exclusively to people on 40. Keratoplasty thermal of the laser, or LTK, implies zapping of 16 points in the external piece of the cornea to contract the fine weave. People can leave 30 minutes after the procedure and reassume generally normal activities the following day. The LTK advantage is that it is a procedure of "no tact", meaning is little occasion of the infection or the loss of vision there. The disadvantage is that the procedure is considered temporary since returns the effect of the treatment -- for much people, on half of the correction goes away in the term of two years. Another disadvantage is that people can become nearsighted the first six weeks, enough to require crystals to lead, and its vision can fluctuate per weeks after the surgery. Rosenthal wishes people who consider surgery of the laser to carefully know and to weigh the pros and the con. the "FDA assigned it that the manufacturers of all lasers of excimer make available to populate a patient informative pamphlet," by mandate says, that it explains this information. If the doctor cannot offer one, Rosenthal says that you must request he. The experts say that the trustworthiness of the correction of the vision of the laser is absolutely good in smooth moderating the levels of refracting errors. But he populates desperate so that the clear necessity of the vision understands the dangers. The patient satisfied with the surgery of the laser is one who has realistic expectations and a careful understanding of the risks and the possible complications of the refracting surgery. Lenses De Contacto -- More Options If you are interested in the contact lenses that use for the first time, or is considering an improvement for the comfort and the convenience, to discuss the last innovations with their doctor of the eye-care will help to make their options easier and to reduce to the minimum the risks. The advances in the materials for the lenses of the precision have made the smooth and rigid gas the permeable contacts -- both main groups of the contact lens -- an option for more people. These medical devices become of many diverse types of plastic, and offer numerous options. With daily wearing down or lenses (at night) extended of the wearing down, the options include frequents or the disposable plan-replacements, materials, bifocals, UV-blocking contacts, and more. There are clear lenses, dyed, opaque, spherical and cleared. So where somebody begins when deciding if the contact lenses are the right option for the correction of the vision, and what to choose? Hal Balyeat, M.D., professor of ophtalmology in the university of the institute of dean To McGee Eye de Oklahoma, say that the people satisfied with her correction of the vision can not need to seem very distant. "if you are already a carrier satisfied with the contact," he says, "you you cannot consider other options of merit when you are using your contacts as well as you you are." The satisfied carriers do not have any allergy typically and they have not developed a intolerancia to the contact lenses. The bottom: If the contact lenses are working for you, Balyeat you say, he is hard to justify other options, such as permanent alteration of the laser of healthy eyes of another way. Balyeat mentions its wife, Marilyn, like example. Although it was a good candidate to the surgery of LASIK, she decided on the contacts of monovision -- centers of a lens surround for above whereas the other lens corrects for the vision of the distance. "in 60," she it says, "I can immovable read without crystals." And that, says to its husband, is the single more important factor: "if you have taste of being able to take towards outside your contacts and still to see upon closing, the surgery is not a compensation of merit." Balyeat adds that much people do not make that the surgery of the laser, made in people on 40, will not let to him consider upon closing without crystals or the contacts unless you choose by monovision LASIK. The quality of the contact lens continues improving. The smooth contacts contain to divide 25 percents for 79 percents of water, they are easy to fit to, and are more comfortable than the permeable lenses of the rigid gas (RGP), thanks to its capacity to be satisfied to the eye and to absorb the water. The smooth lenses are not probable to explode towards outside or to capture the foreign material as dust underneath, because the Additional-fine smooth lenses are the hard lenses are available for the very sensible eyes. Whereas the capacity to carry out the permeability of smooth lenses, he of the oxygen of the increases of the water also makes more fragile. And the smooth lenses are more probable to absorb chemical agents and the remainders in the hands of the carrier. The RGP lenses are more durable and resistant to the accumulation of the deposit, and give the clarificante, one more a more fragile vision generally. They tend to be less expensive on the life of the lens, but the initial cost is often more stop. RGP makes contact with enemy with finally several years, whereas the smooth contacts, depending on the type, are meant to be replaced after the periods that extend as of a day around a a year. In addition, the RGP lenses can be marked to demonstrate what lens is why eye, and they it is less probable to be torn or to tear, doing them easier to direct. Nevertheless, it often takes several weeks to obtain used to use the rigid lenses, compared with several days for the smoothness. Many changes are happening in the world of available (defined by the FDA according to the rejected used thing once and) and frequent or the plan-replacement makes contact with enemy with. The last innovations include the daily disposable materials, bifocals and the contacts toric for the astigmatism. "he is healthier to replace the lenses more often," says that James Saviola, O.D., head of the ramifica vitreoretinal and devices extraocular in the FDA. "and if you reuse your lenses, you need to do something more than in the saline solution." The FDA approved in 2000 that first "no-they rub" the solution of the cleaning for the contact lenses. The solution adds a safeguard for the people who do not rub her lenses -- but if -- when cleaning. first solution applied initially less No-rubs the directions for this of the lenses replaced within a month or. Now, it has been extended to include the lenses that are replaced after a month or more. Other products also are available that it has no-rub the directions for the lenses replaced within a month. But Saviola remembers people who in some cases, rubbing continue being necessary to maintain her lenses clean. A new generation of the materials of the lens is studying. The lenses done of these materials provide a greater amount of permeability of oxygen, say Saviola. Two types have received the approval of FDA, one by seven days of continuous wearing down, the other by 30 days. Others, such as the continuous contact of the wearing down 30-day, now is being considered. The most serious preoccupations of security with any distribution of the contact lens with use at night, or extend-use. Rigid or smooth, to use these types of contacts it increases during the night the risk of the corneous ulcers -- eruptions infection-caused in the cornea that can lead to the blindness. The symptoms include changes of the vision, rojez of the eye, malaise of the eye, and the excessive torn one. Extend-use the rigid lenses also can cause the new unexpected formation, sometimes undesirable of the cornea. Saviola advises that that maintains the lenses clean, replacing them often, and using them as prescribed by its specialist of the eye-care increases the security of contacts that use. People do not have to use the contact lenses more of length than the time prescribed by her doctor of the eye-care. But what it or it prescribes, she is safe to request written instructions and to follow them carefully. The patient fillings of the package accompany generally the contact lenses, and Saviola accentuates that people who are not offered this information by her doctors must request he. For that they have not been able to use contacts, the implantables lenses can be an option in the future. Orthokeratology Orthokeratology, or ortho-K-K, are a procedure that uses the contact lenses of RGP to change the curvature of the cornea to improve its capacity to refract light and to be centered successfully in objects. Desemejante de regular RGPs, RGPs ortho-K-K has a design that can again form the curvature of the cornea. This method, nevertheless, does not produce a permanent result. With ortho-K-K conventional, the lenses are used near eight hours to the day. After the cornea has reached the best form after the optimal vision, the lenses are less frequently used -- perhaps by some hours every two or three days. If somebody begins and later he continues ortho-K-K, Saviola says, the corneas will return possible to its natural state. People choose refracting surgery of excessive ortho-K-K because the effects of Ortho-K are not permanent. A disadvantage of ortho-K-K is that the clear vision can fluctuate during the day. Also, ortho-K-K can take many months to change the vision of a person. One more a technique well-known outpost as takings "ortho-K-K" accelerated less time, and can be recommended to reach a fast effect. From 1998, Saviola says that the FDA has cleared a number of lenses ortho-K-K of the daily wearing down, but the lenses ortho-K-K have at night not been approved. The best candidates to the prescription ortho-K-K are the people of any age that has low amounts of nearsightedness or of the astigmatism. The goal is to bring the vision of the person at least to 20/40. But for some, the will ortho-K-K provides 20/20 vision. Corneous segments Of Anillo In 1999, the FDA approved a procedure surgical not-laser to correct small amounts of nearsightedness. The corneous segments of the ring are very small, clear the pieces in medialuna of plastic polymer that they are implanted in the cornea. The segments of the ring again form the cornea so that it gets to be flatter, allowing than approach slight rays on the retina and producing the acute vision. The procedure takes near 15 minutes and it becomes on a base of the patient noncommitted. Before surgery, the drops of anesthesia are put in the eyes. Smooth the corneous ring still is studying to treat hyperopia and the astigmatism, although these applications have not been approved by the FDA. Several others you implant intraeyeglasses and corneous, of several companies, also they are in several stages of the clinical study. Eyeglasses -- the Old safe Resource In some cases, the modern technology can provide the best option of the correction of the vision. In those cases in which it cannot, eyeglasses can often help. The crystals correct refracting errors adding or reducing energy that focuses to the cornea and the lens. The needed energy to be centered images directly in the retina is moderate in diopters. This measurement is also its prescription of the lens. Like the contact lenses, the crystals come in all the forms and sizes, offering an arsenal of the options for the function and the way. The marks of the lens, for example, are more durable and tout the materials such as "new metals titanium and of the memory." The lenses are deluente, and more hard lighter. The options of the lens include the layer antireflective, the bifocal dyes light-that they change, lenses (line-free) progressive, and polycarbonate -- the most resistant material to the shocks of the lens available. Perhaps the greater worrisome aspect for the carriers of the lens is the constant sensation something that feels in the nose, in spite of the advances such as the crystals of featherweight. Water Paul Trossevin that falls, W.Va., knows to all uncomfortable sensation something the too much well perched permanently in his nose. Like a scar that never descolora, the crystals of Trossevin have been with him every day since it was 4 years as an older person. Now 35, he says, "was a time at which he would have made any thing to obtain ruined of my crystals." Or he thought so. Although he could never use the contact lenses due to the severe plain of his cornea, Trossevin was a candidate to surgery of the eye of the laser. But a thing that he could not obtain from any doctor was a guarantee that after the surgery he did not consider starbursts and halos around the lights -- a great preoccupation since he leads a good part of the day and plays baseball at night. "the guarantee was everything," he says. "when it could not give that me, my crystals acquired the new meaning suddenly -- a guarantee of the good Vista that they have given me by more than 30 years." Anticipar Between some of the most intriguing progresses in the vision-correction the pipe is an alternative to LASIK, call LASEK, to a new avenue for the refracting surgeons who disturbe the fine weave less corneous than his contrapartes sound-resemblances. It also has to char it of the investigation devices that could be put within the eye to correct refracting errors. During the next decade, there are safe to be improvements in techniques and present technologies, in addition to new procedures. Extremities Of the Eye Whereas you cannot make any thing on age or genetic maquillaje, you can eat a balanced diet, the sun glasses of the wearing down that blocks the ultraviolet light, and is able regular examinations of the eye to help to maintain the good vision. The regular examinations of the eye are important because they can detect early samples of the disease long before the disease leads to the loss of the vision. The doctors recommend that each one has an examination of the eye shortly after birth, and at least every few years until age 40. After that, the eyes are due to routinely verify every 2 or 3 years.