the answer thankfully is not. Surgeons use a very precise instrument called the microkeratome (See Figure 3) which makes LASIK very unique compared to other surgeries. This device is a mechanical shaver that has a sharp blade, which moves back and forth at very high speeds (See figure 2). After a suction ring has been placed on the cornea, the microkeratome is place on top of the cornea and advances across it at very small increments creating a flap that is only 1/3 inch in diameter. This instrument cuts the cornea at a uniform thickness and creates a portion of the cornea uncut. After the suction ring and the microkeratome have been removed, the corneal flap is folded back (See Figure 4), exposing the middle portion of the cornea. Also in LASIK surgery, the excimer laser can be used at different frequencies and therefore produce different desired 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 ha...
