MYOPIA, HYPERMETROPIA, ASTIGMATISM AND PRESBYOPIAMYOPIA, HYPERMETROPIA, ASTIGMATISM AND PRESBYOPIAMyopia, Hyperopia, Astigmatism and Presbyopia

MYOPIA, HYPERMETROPIA, ASTIGMATISM AND PRESBYOPIA

WHAT ARE SOME EYE DEFECTS?

The eye utilizes two lenses to “take” images and focus them in the retina, one lens is the cornea and the inner lens is called the crystalline lens. Eye defects occur when the image that the eye perceives is not received clearly in the retina, it being because the eye is longer ( myopia) or shorter ( hypermetropia) than a normal eye, or because the cornea is not perfectly spherical and therefore distorts the images ( astigmatism). Eye defects or refraction problems are the names used to classify the visual difficulties many people experience to see things at a distance or that are close, due to the blurriness of the images in the retina. These problems lead to a burry vision and can cause disturbances and discomfort in everyday activities.

WHAT OPTIONS ARE AVAILABLE TO CORRECT THEM?

There are various options available to treat these eye defects. The most common one is the use of visual prosthesis ( eye glasses or contact lenses), but this is only a temporary solution. These two options are more simple and less expensive but only in the short-term. They also have may disadvantages?
THE TREATMENT WITH EXCIMER LASER: There are a variety of surgical treatments available to treat eye defects. Commonly, these treatments are known as refractive eye surgeries, and their objective is to modify the cornea so that the light can be properly focused in the retina when it enters the eye, allowing for the eye to produce clear images. This surgical solution the majority of the time results in the elimination of the need to use eye glasses or contact lenses and allows the patient to live life freely without the use of corrective eye lenses. Forty year ago, the patron of refractive eye surgery, Dr. Jose Ignacio Barraquer M, solidified his roots in the correction of eye defect by modifying the shape of the cornea. The techniques used since then have changed and new ones have been developed, such as the laser, thanks to the principles and formulas established by Dr. Barraquer. As a result of the advances seen in the refractive eye surgery with the Excimer laser, the most commonly used in North America, this surgical procedure is now a very fast and simple way to correct visual defects with great precision. It is many times the safest, most convenient option, and in the long-term, the cheapest.
WHAT IS THE EXCIMER LASER?
The world LASER means: Light amplification by stimulated emission of radiation. The word EXCIMER means: excited dimers of inert gases. This machine is able o produce a laser through the excitation of the Argon Fluoride, producing as light with a 193nm wave ( UV light). Every laser beam removes a microscopic portion of the tissue, evaporating it with a very low production of heat, leaving the subjacent tissue unharmed. This mechanism is a photochemical.
HOW DO I KNOW IF I AM A CANDIDATE FOR THIS TYPE OF SURGERY?
Any patient with a visual defect that causes blurry vision, be it near or farsightedness, and wants to learn if they are a candidate for refractive eye surgery, should first consult an eye specialist to determine the type of severity of visual defect, and if it falls within the limits of defects hat the Excimer Laser is able to correct. Myopia until 14 diopters and hypermetropia until 7 diopters is considered operable. A more in depth analysis of the eye is done to make sure no other pathologies are present ( such as corneal diseases, advanced glaucoma, or cataracts ) that might impede a surgery from proceeding. Other lifestyle aspects of the patient are also taken into consideration, to see if this type of surgery will translate into a more functional life or not. If the results are all within the parameters established for the laser surgery, the next step is to undergo the two following exams. 1: cornea topography, which is a computerized photo of the surface of the eye that evaluates if there are other diseases or abnormalities present such as Keratoconus, and 2: a Pachymetry, which determines the thickness of the cornea, as a cornea cannot be too thin or too thick in order to operate. If the results for all of these exams fall within the acceptable parameters, a patient can proceed to surgery.
WHAT IF I HAVE PRESBYOPIA?
Presbyopia, the difficulty to see very close, is an age- related condition that is common after age forty. It is due to the fact that the internal muscles of the eye are no longer able to move the lens, which was once the flexible lens that changed shape to change the focus from far to near and vice-versa. There are various procedures available to treat this condition, and they have demonstrated that the same technique cannot be used on all patients to treat the same condition. As can be observed, the rates of success of these procedures vary greatly depending on the initial visual defect of each patient. Generally, the techniques used to correct Presbyopia have higher rates of success with patients that have hypermetropia. Of the techniques available, the most common one is called “monoviion”, which involves leaving one eye with good distance vision and the other eye with a bit of myopia to facilitate near vision. This concept is not a new one and has been used for many years on patient that are long time contact lens users. The brain accepts this kind of monovision in about 80% of cases, resulting in the patient having good distance and near vision without the need to use contact lenses and without noticing the difference in vision in the eyes. For the specialist to be sure that the patient can tolerate this kind of vision or not, special contact lenses are prescribed for three days so that the patient can experience what “monovision” feels like and can decide, depending on the level of comfort of the patient, to carry out the procedure or not.