The reason for this is that their eyes are shaped like a football. Different regions of curvature result in light not falling on the same spot on the retina as it does in a normal eye. This procedure involves making microscopic accurate cuts with a diamond blade under a high powered microscope in the area of the astigmatism. It is extremely safe because the cuts are made outside of the visual axis, thus posing no threat for damaging the center of the cornea. The procedure is done under topical anesthetic, is pain free, and is done in the doctor's office typically taking five to ten minutes.
Enhancements involve either adding additional cuts or deepening existing cuts.
Improved vision is noted immediately, but for maximal vision to be attained, may take from two to six weeks. The major risk of this procedure is perforation of the cornea with resultant infection. In experienced hands this rarely occurs and even when it does occur, can be prevented if treated promptly. Presbyopia typically occurs when we reach our mid-forties requiring us to need glasses for reading. As we get older, this muscle becomes stiffer and we lose our ability to accommodate, thus see things close by and need glasses to help us to do this.