.. results in the same patient. Each laser pulse in a LASIK procedure removes ten-millionths of an inch of corneal tissue in twelve-billionths of a second while in a PRK procedure, the laser removes about twice as much in about the same time.
The amount of corneal tissue removed depends on how nearsighted or farsighted the patient is (Gorman, 60). The more nearsighted a patient is the more tissue must be removed to obtain a flatter cornea, and the same goes with farsightedness, except the cornea has to be made steeper.Back when Barraquer started Keratomileusis In Situ, he noticed that he was having great success with patients who had myopia and did not know why patients who had hyperopia and astigmatism were not enjoying the same results. Surgeons even today notice, that after LASIK, patients who have myopia before the surgery get better results than patients who have other vision ailments (such as hyperopia, astigmatism, and presbyopia) (Gallo, 128). Ophthalmologists now believe that the reason has to do with how the excimer laser reshapes the cornea (Gallo, 128). In a patient who has myopia, the laser makes the cornea flatter while in a hyperopic situation, the laser makes the cornea steeper. The problem does not come during the surgery but after it when the cornea bed reshapes itself to match the “new” cut cornea. They call it the cornea bed because it is just like a bed because as you lie on a mattress, it will reshape itself to the contour of your body.
Once the cornea is made flatter, the cornea bed has no problem reshaping itself to the new contour; however, this is not always the case for hyperopia and astigmatism. The corneal bed, which is located behind the outer layer of the cornea, has trouble reshaping itself to either a steeper or narrower shape. Ophthalmologist do no fully understand why this occurs, but they do urge that LASIK provides better results for people who suffer from myopia and therefore, that is why the vast majority of people who undergo LASIK do so to correct nearsightedness (Buratto, 9). The results of LASIK are astounding (Gallo, 129). The obvious goal of LASIK is to get a vision of 20/20, which is perfect vision.20/20, 20/40, and so on are measures of visual acuity; a person with 20/40 needs to stand twenty feet away from something that a person with 20/20 can see fine from forty feet away. Last March, the Journal of Ophthalmology stated that 3 months after the surgery, seventy-percent of the patients who have had LASIK, have 20/20 vision. A follow up 2 years after the surgery showed that sixty-three-percent kept the “perfect vision” while ninety-nine-percent had at least 20/40 vision.
The amount of vision improvement generally is tied to the degree of nearsightedness and farsightedness before the surgery. Dr.Stephen Slade, who is one of the pioneers of LASIK said, “The less nearsighted or farsighted you are, the more likely youll get 20/20. For low myopes, ninety-five percent can get 20/20. For high myopes, the figure might drop to sixty percent.” Usually, for every good thing that comes along, there are some unfavorable circumstances that follow; however, there are not too many complications or side effects in LASIK (Shovlin, 113). Complications are very rare, but they will be more common in patients with high nearsightedness, farsightedness, and astigmatism because they require more laser treatment. Also no patient has ever become blind after a LASIK procedure; however, there are a list of possible complications that can result in decreased vision after the surgery.
One complication results from the anterior cornea (flap) being placed unevenly after the laser treatment, which usually results in a corneal haze. Another possible complication is that of an infection, which only occurs in .5 percent of the time. However, by far, the most common complication is under or over correction, which are due to the laser removing either too much tissue or too little tissue respectively. Under correction results from lack of corneal tissue being removed and is usually fixed with a procedure called “touch up” (another mini LASIK procedure but without any further cuts). If too much corneal tissue is removed, the problem is a lot more serious because surgeons must perform a Keratophakia, in which they have to add corneal tissue. Under correction and over correction are the main reasons that all patients do not receive 20/20 vision, and that is why no patient can ever be guaranteed perfect vision.
Last January, a review in LASIK of 1,062 eyes found that complications occur in about 5 percent of the cases. Tests before the procedure are now being taken more seriously than before, because those tests determine how much laser treatment is needed. While the recovery period of LASIK is remarkably short, forty-percent of people who had the procedure see halos or starbursts around bright lights for several months (Buratto, 5). Ophthalmologists believe this effect seems to be caused by the edge created between the treated and the untreated part of the cornea which bends and distorts the light as it enters the eye. Seeing halos or starbursts usually occurs during night, when the pupil dilates and the edge of the cornea falls right into view and for this reason, people with exceptionally large pupils should not undergo LASIK.
These starburst effects, as ophthalmologists call it, usually go away after a few months.Little research is available on LASIKs long-term safety and effectiveness, but there is information available on PRK. Last year, a review in ophthalmology traced eighty-three British patients who underwent PRK in 1990, and found no serious complications in any of them. This is attributed to the amount of untouched, deep cornea (approximately fifty percent of the entire cornea), which maintains the eyes original overall shape.
This is opposite of RK which left only 10% of the untouched cornea (Voelker, 1494). Despite its increasing popularity, LASIK is not for everyone.People with extra-thin corneas are not good candidates of this surgery because the surgeon does not have enough tissue to work with. Ophthalmologists also turn away people who have rheumatoid arthritis and diabetes because they have problems with dry eyes, and are hence poor healers.
As people approach forty years old, they begin to lose the ability to change their focus from far to near (presbyopia), but dont worry, it is natural in everyone. Baby boomers who have LASIK to try to correct presbyopia, usually trade their distance glasses in for reading glasses (or vice versa). Surgeons are now answering this problem with “mono-vision”, which is correcting one eye for far distance and the other for focusing on close distances.
After this procedure, the brain adapts, using each eye for different functions; however, patients often experience blurry midrange vision and have depth perception problems.”Most patients dont mind it, but it drives some people nuts,” says Dr. Slade. “There is a revolution happening in vision correction,” says Dr. Guy Kezirian, a refractive surgeon in Arizona, and spokesman for the International Society of Refractive Surgery.
“Were seeing a stampede of people interested in a surgical alternative.” The question I ask is, why not? Glasses can be very inconvenient, and contacts can be a hassle, so why not venture in this vast, growing field of LASIK? LASIK is not just an eye operation anymore, it is a 2 billion dollar a year industry that has revolutionized the way surgery is looked at.Usually costing two thousand dollars per eye, LASIK is not a surgery that anyone can afford, especially since it is not covered by insurance. Yet when asked, a LASIK patient consistently states that the surgery was one, if not the, best thing which they have ever done for themselves: no worries of sleeping with contact lenses and contracting a sight threatening infection (Slade, 254). No fear of scuba diving or swimming with contacts, and no fear of waking up 3 a.m.
after having heard noises downstairs, and not being able to find your glasses. LASIK surgery gave Diane, a forty-five-year-old doctor assistant, a newfound sense of freedom.Before the surgery, she couldnt clearly see her feet when she was in the shower, but now after LASIK, she is taking rock-climbing lessons with her twelve-year-old daughter; something she would have never done if she were wearing glasses or contacts.
Stories like this are becoming common as Americans flock to eye doctors at record rates for this “surgical fix”. LASIK is blossoming like a flower in the Fertile Crescent and soon everybody will be taking advantage of its wondrous gift that it provides; the gift of sight.