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Laser Vision Correction and Our Eyes: Our eyes are the windows to the world, and our vision determines how we perceive the world around us. As humankind has always longed for better vision, technology has continuously evolved over the past decades. Also today's active lifestyle demands for visual performance that we can rely on, night and day. That is why laser vision correction has been chosen by millions to correct vision. Our outcomes allow your vision to come to a new level called High Performance or Definition vision just like our high definition plasma televisions. The eye allows us to see by focusing and
processing light. The eye changes light rays into electrical signals, then
sends them to the brain, which interprets these electrical signals as visual
images. Among the more important parts of the human eye are the following: Cornea, Endothelium, Epithelium, Stroma, Lens, Pupil, Iris, Vitreous Body, Optic Nerve, Retina, Sclera. The eye functions on the same principle as a camera. The iris, or colored portion of the eye, acts as the shutter to regulate the amount of light admitted into the eye. The cornea and the lens, located behind the pupil, serve to focus the light rays from the object viewed onto the retina in the back of the eye. The retina then transmits the 'picture' of the object viewed to the brain where the object is then 'seen'. Common Vision Problems & Refractive Disorders: The most common vision problems are: Myopia, Astigmatism, Hyperopia, and Presbyopia. These are called 'refractive disorders' or 'refractive errors' because they have to do with how the eye focuses or refracts light. If an individual has normal vision, light will enter the eye through the cornea and will be bent to a single point on the retina at the back of the eye. If there is a refractive error, the light is not bent to a single point on the back of the eye.
Presbyopia occurs when the lens inside your eye loses its elasticity, making it more difficult to read smaller print. This loss of elasticity affects the ability of the eye to focus close up. This usually occurs between the ages of 40 and 50. Everyone experiences presbyopia at some point as they get older, resulting in nearsighted people to begin wearing bifocals in their forties, and those who never needed glasses before may require reading glasses. The one advantage to mild myopia (nearsightedness) once you begin to be presbyopic is that you may be able to remove your glasses to read (your myopia effectively counteracts your presbyopia). Presbyopia was previously thought to be caused by a hardening of the lens of the eye, which made it difficult to focus. This loss of focusing ability occurs in nearly everyone by age 50. You will become aware of this condition of aging when you notice difficulty reading due to fuzzy vision. With further aging, the ability to focus near objects is lost. However, a revolutionary new understanding to this age-old problem has been proposed by physicist Dr. Ron Schachar MD, Ph.D. He has published both theoretical and laboratory data which support the concept that presbyopia results from physiologic growth of the crystalline lens of the eye with age. The increase in the size of the crystalline lens reduces the distance between the edge of the crystalline lens and the ciliary muscle. Because of this decrease in distance, the ciliary muscle, which changes the shape of the crystalline lens by traction on the zonules, is unable to exert sufficient force to alter the shape of the lens. This results in presbyopia. Click to view illustration.Understanding Your Prescription: Common vision disorders of the eye such as nearsightedness, farsightedness, and astigmatism are each measured in units called diopters. Diopters represent the amount of correction you need to correct your vision. The more nearsighted, farsighted, or astigmatic you are, the higher your prescription in diopters. Here is a way to decipher your prescription: Now let’s take a look at a prescription for both eyes: "OD -4.25 -1.50 x 180,
OS -4.50 -1.25 x 175, +2.25 Add", represents a typical prescription for both
eyes. OD stands for right eye and OS stands for the left eye. The “add” at the
bottom of the prescription is for the reading part of glasses that have bifocal
lenses. It might be unusual for anyone under the age of 40 to need this.
Therefore, a prescription of; "OD -4.25 -1.50 x 180, OS -4.50 -1.25 x 175"
indicates that the patient is moderately nearsighted in both eyes, with a
moderate degree of astigmatism in a horizontal direction in each eye. Correcting Vision Problems In The 20th Century Before 1973: Until 1973, refractive error could only be corrected with either glasses or contact lenses. These methods for correction are effective for many patients and are useful in restoring better vision without surgery. Glasses are most commonly used to correct vision. Patients with a small degree of refractive error can be corrected effectively with glasses to improve their vision. For patients with large amounts of refractive error, glasses are thick, and generally decrease the size of the visual image by as much as 25%. Any large amount of refractive error will distort image size as much as 50%. Contact Lenses, both hard and soft, are designed to fit directly over the cornea to correct vision. Patients must be adept at inserting and caring for the lenses in order to wear them successfully. The contact lenses may be somewhat irritating to the eyes, and patients occasionally develop allergies to the cleaning solutions. Our center has learned that nearly all patients prefer vision correction surgery to contact lenses and that it is safer for the health of your eye. Today, laser vision correction is one of the most popular surgeries performed in the United States. Millions of people have lost their dependence from glasses and contact lenses. What many people do not know is how far the science of refractive surgery dates back. In fact, surgical vision correction started all the way back in the 1970's in Bogota, Columbia. Physicians started to travel to Colombia to visit Dr. Jose Barraquer. He had developed a technique called corneal shaping in which he modeled corneas in order to improve visual acuity.
In the early 1970's, a Soviet eye surgeon, Professor S. N. Fyodorov, reported good results in the correction of myopia after using a surgical technique called Radial Keratotomy (RK). Radial Keratotomy surgery is performed by making a series of fine microscopic incisions on the surface of the cornea in a radial or spoke-like pattern, to flatten the cornea thus focusing light rays on the retina resulting in normal vision. In the late 1980's Dr. Thomas A. Shealy began to work on refining RK into a better procedure through the development of new techniques and instrumentation. This work started under the tutorialship of Ron Jensen MD and Charles Casebeer MD. Although the majority of patients could see 20/40 or better unaided, the precision and predictability of the procedure was limited to lower degrees of refractive error. After performing more than 6, 000 procedures, Dr. Shealy began using lamellar procedures developed by Dr. Luiz Ruiz MD a student of Dr. Jose Barraquer to correct higher ranges of refractive error using the automated lamellar microkeratome. This was also used successfully to treat all degrees and types of refractive error. IBM’s Etching Computer Chips: The Development and the use of LASIK (Laser in Situ Keratomileusis) in the 20th Century at Our Center and by Professor Theo Seiler in Dresden Germany More than two decades ago, the excimer laser laser was invented to etch microchips at IBM's Watson Laboratories. Then, the discovery was made that the excimer laser can also be used to effectively re-sculpt human tissue, particularly the cornea, with a great degree of precision. The excimer laser works in an area 1/100th the width of a human hair and may remove as little as 1/40th of a human cell. The excimer laser allows for an unparalleled degree of predictability. Each pulse of the laser can remove 39-millionths of an inch of tissue in 12-billionths of a second. This enables an experienced surgeon to achieve remarkable accuracy while maintaining excellent control throughout the procedure. Today, the excimer laser is capable of treating a wide range of refractive errors. In the 1990's the FDA approved Photo Refractive Keratectomy (PRK) in the United States for the treatment of nearsightedness and later farsightedness. In PRK the uppermost layer (epithelium) of the cornea is removed before the laser is used to remodel the corneal surface. The epithelium grows back within a few days following the treatment. Even today, many people that have very thin corneas are candidates for a PRK treatment. In 1998 the FDA approved yet another procedure called LASIK. In January 1996, we acquired an excimer laser developed by Professor Theo Seiler and have used lasers since then along with a microkeratome as a further improvement in the correction of refractive error. This procedure is called LASIK or Laser Assisted Intrastromal Keratomileusis. LASIK is currently the most common type of laser vision correction procedure, and corrects all prescriptions, regardless of the amount of refractive error. It can be preformed after radial keratotomy, keratomileusis, and cataract surgery to further sharpen vision. We have corrected with incisional keratotomy and automated lamellar keratoplasty up to -21.00 diopters of myopia, +7.00 diopters of hyperopia, and +8.00 diopters of astigmatism. Since 1996 we have acquired and have experience with four different excimer lasers to include Summit Apex Plus, Summit Excimer, Nidek EC500, and the Allegretto Wave Laser. Each has specific features that allow broad beam expansion to scanning beams to flying spots with wavefront algorithms. Our new Allegretto Wavefront Optimized flying spot laser with a 200-KHz tracker has produced a 50% gain in vision over any glasses or contact in our myopic patients, and a 44% gain in vision over any glasses or contacts in our hyperopic patients. "WOW, WOW, WOW" vision has been produced, and the staggering thought of seeing better than anyone has seen before in the human history is being realized.
Then in 1999, Professor Theo Seiler performed the first wavefront-guided treatment in Zurich on a WaveLight laser. This marks the advent of wavefront technology in vision correction. Since the beginning of the new millennium, wavefront-guided technology has started to become popular throughout the United States. Prof. Seiler's idea of treating the finest aberrations within the optical system of the eye let many physicians and patients to hope for more. The idea began to take vision beyond the bounds of 20/20. For the first time since 1999, the FDA approved an entirely new laser for use in the United States: the ALLGRETTO WAVE built by WaveLight. The ALLEGRETTO WAVE was designed in cooperation with Prof. Seiler from the ground up to perform customized treatments with the speed and precision necessary. A first in lasers, the ALLEGRETTO WAVE has wavefront-principles directly integrated into the standard treatment. Despite all the technological advancements in vision correction surgery, the ophthalmologists experience is still the most important factor for a successful and satisfying outcome. The LASIK procedure requires a great deal of technical skill and training to perform properly. Dr. Shealy has performed more than 20,000 vision correction surgeries, was the first surgeon in Indiana and is one of the very few specialists in the United States, to dedicate his practice entirely to laser vision correction. So you will receive thorough care and have access to a highly experienced doctor at the Shealy Eye Laser Center. The Advantages of LASIK from 1996 to 2004 are listed below:
The advantages of LASIK have been supplanted after the year of 2004 by newer methods and lasers which addressed visual quality. Before LASIK we only had PRK or photorefractive keratotomy which was performed on the surface of the cornea in a non-cutting manner. With the advent of newer lasers that addressed nighttime glare and quality issues, it became apparent that improvements could occur in traditional LASIK or laser vision correction. The first improvement was to improve the beam quality and placement of the beam to maintain the normal curvature of the cornea without interruptions in the refractive surface that could affect nighttime vision when the pupil dilated. Suddenly, patients noticed that their vision was crisper and more in focus and free of visual disturbances especially at night. Consequently, laser treatment was replaced by newer lasers that addressed visual quality. From 2005 to 2006 we learned that LASIK involving cutting could produce complications like epithelial ingrowth, (ectasias) bulges, (stria) dislocations, and eye dryness by cutting the delicate corneal nerves. With the advent of newer pharmaceutical agents especially mitomycin-C in the year 2006 and the development of non-cutting epithelial separators, patients could regain their functional vision and return to work relatively quickly without fear or safety mindedness. The healing time became two days instead of the usual six to seven days with standard PRK. Postoperative discomfort was reduced by the use of new pharmaceuticals, most of which were non-narcotic in nature. Using these pharmaceuticals along with new improvements in contact lenses nearly all patients were able to return to work and were comfortable within two to three days postoperatively. Only 12% of the patients required narcotic medications after the first 24 hours and a large portion did not take any medications at all. Later with the improvements in non-steroidal anti-inflammatory medications all narcotic medications were replaced with Aspirin or Tylenol with only minor irritation like contact lens irritation. No patients required medication after day two and were quite functional after the second day. LASIK appeared to lead to wrinkling of Bowman's membrane and produced more re-treatments and lesser outcomes than surface Epi-Laser or advance surface treatment. Thus, the Shealy Eye Laser Center abandoned mechanical LASIK in the year 2006 and now offers all-laser LASIK for those patients who do not want the complications associated with microkeratome cap or flap LASIK. Since 2006, the Shealy Eye Laser Center has been performing surface ablation with amoils brushing or epitome separators which do not physically cut into the stroma of the eye. Some patients who've had mechanical injuries to the eye with metal fragments may be required to avoid cutting into the stroma with a laser or mechanical blade to avoid surface irregularities which may induce regular or irregular astigmatism. In some instances <1% incursions occurred without significance. By 2007 newer ways of producing LASIK flaps called SBK or sub Bowman’s keratomileusis with thin flap microkeratomes and Femtosecond lasers made the technology of high performance and high definition vision possible. 98% of patients were completely satisfied with vision exceeding glasses and contacts 98% of the time. In 1.7 million patients there was only 1 or 2 lost lines of best vision per 1000 treatments with 67% gaining at least one line vision. The argument for safety and quality of sight became compelling. The LASIK procedure is performed under high magnification with an operating microscope. Topical anesthetic drops are administered to anesthetize your eye. Patients remain awake and comfortable. The procedure takes approximately 15 minutes for both eyes, and consists of making a corneal cap to be hinged to the side as laser ablation is performed on the inner layers of the cornea. Patients should have a prescription that has been stable for approximately 12 months. Therefore, patients as a rule should be 18 years of age or older. There is no upper age limit. Patients with lower or moderate degrees of myopia will have the most immediate and best results most of the time. Patients must have healthy corneas, devoid of keratoconous. Blended vision is a technique developed for people with presbyopia in which one eye (usually the dominant eye) is corrected for clear distance vision, and the other eye is corrected for comfortable near vision. Blended vision is a process of correcting both your distance and near vision without glasses. This is possible by correcting your dominant eye for distance and your non-dominant eye for near. This process takes about 3 to 6 weeks to adapt to called neural adaptation. Most people in their 40's and 50's do very well with blended vision (approximately 80-90% adapt). If for any reason you are not satisfied with your blended vision after your treatment, it can be reversed by correcting the non-dominant eye to distance. A reversal can only take place after the eye has fully healed and stabilized - which takes approximately 3 months. A trial of blended vision is possible by using a weak contact lens in the non-dominant or dominant eye. Depth perception is not decreased along with night vision if less than 1 diopter of nearsightedness is made or retained in the non-dominant eye. This situation is called modified blended vision and usually does not affect the distance vision for driving. All of us will experience presbyopia as we become older and usually patients are affected between age 40 and 48. The satisfaction rate with blended vision is 99%. Treatment and Procedure Walk-Thru Where is Laser Treatment Performed? LASIK refractive surgery is performed as an out-patient procedure at the Kelley-Fyodorov-Seiler Surgical Center located in the lower level of the Shealy Eye Laser Center. We have performed more than 20,000 procedures to eliminate eyewear. Prior to the day of your surgery, you will need to make the following arrangements:
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