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LASIK

 

My eyes are not really bad enough for me to want the procedure, but in the past month, two people close to me have had the LASIK procedure performed and i thought I’d post some information, pictures and a movie of the procedure for 1) your edification and 2) because it’s about eyes and I’m all about the eyes.

LASIK is an acronym for Laser Assisted In-Situ Keratomileusis. What does THAT mean you may ask… Well, in short, it’s a procedure to help improve vision by changing the refractive properties of the eye by modifying the optics of the cornea. It turns out that the cornea has a significant ability to refract light through the eye and can be reshaped to better focus light on the back of the eye or retina.

The typical procedure is after an initial exam and evaluation for candidacy, the corneas are topographically mapped out to determine how to shape the cornea. This evaluation allows for the best possible image representation on the back of the eye or retina based upon a mathematical model generated by the mapping. This computational mapping then allows an excimer laser used for the surgery to be programmed to remove the precise amount of corneal tissue that exactly duplicates the topographic map and optical model in each patient. Essentially it is a custom treatment designed for each patient.

You are asked to not wear contact lenses for approximately ten days prior to the surgery as they can actually alter the shape of the cornea. On the day of the surgery, you are often given an anxiolytic like diazepam to help take the edge off and some anesthetic for the eyes via eye drops. 

 

The actual operation involves the creation of a corneal flap either with a laser or a knife called a microkeratome. This flap in the cornea is then reflected back revealing deeper layers of the cornea called the stroma that is then reshaped through the use of an excimer laser that burns or vaporizes away the extra tissue a few micrometers at a time. The picture below is an example of the use of a laser to cut the flap. It seemed easy enough, but when it came time to reflect the flap, it appeared to be more difficult after the laser cut than it was with the knife. My bias from a limited observation of two separate procedures would be to use the microkeratome.

Because a corneal flap is created, this procedure is not for everyone. For instance, those individuals who either participate in sports that may in fact cause injuries to the eye are encouraged to have a different procedure performed called PRK or PhotoRefractive Keratectomy. This procedure causes less anatomical alteration to the cornea itself and does not induce a risk of dislocated corneal flaps that may occur even years after having a LASIK procedure performed. The PRK procedure is a bit more painful and recovery of vision is slower than with LASIK, but for those that participate in aggressive sports or certain jobs within the military, this procedure is preferred. In fact, I believe that PRK is now accepted for vision correction in combat pilots and for those individuals in the special forces. I am not sure when this policy went into effect, but it happened late enough to short circuit my career in the armed forces fifteen years or so ago.

 

For many people, the vision correction surgery allows for 20/20 vision, and sometimes vision is even better than that allowing most people to completely dispose of their contact lenses and eye-glasses. Eventually however, most folks will need some glasses for reading as our eyes age and we are less able to change the refractive properties of our lenses.

 

Check out the movie of the procedure here. Note: The movie of a surgical procedure is in Quicktime format and is about 75MB in size.

 

Remember that this is surgery and as such should not be taken lightly. These are your eyes and I would suggest not going the cheap route and having LASIK performed in your local mall. Do the research on your provider and don’t be afraid to walk away from someone you are uncomfortable with. There are potential complications and the pre-operative evaluations and care combined with the post-operative care are most important.


Categories: Science.

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2 Responses

  1. I want to know about PRK surgery and I went to docotr for my eye for exam and dallas, tx location

    Deborah SimmonsMay 9, 2011 @ 6:35 pmReply
  2. Hey Deborah,

    I’d suggest you talk with your physician for specifics, but there is also a decent entry on Wiki here:
    http://en.wikipedia.org/wiki/Photorefractive_keratectomy

    bwjonesMay 9, 2011 @ 7:08 pmReply



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