Monday, October 10, 2011

Do You See What I See?

     When I was young I was always confused when someone said they were nearsighted or farsighted.  If someone could see something far away then why not see something under their nose?  Chapter 3 helped me to understand just how amazing the human eye is and all that I take for granted as I go through the day and cover so many activities. 

     Previously there was not a surgery to correct vision for someone that was not able to see in the distance.  For those that wished to rid themselves of  glasses the only alternative was contact lenses and that required some maintenance and sometimes could be bothersome in the eye.  The first contacts were glass and they posed a risk in the eye, if it were to break and scratch the cornea. 
     My friend Debbie can certainly attest to this,  because I managed to break her contact and  she was rushed to the hospital.  College years and summer shore houses involved skill at  playing "quarters" and shooting bottle caps and other games that our parents would not have approved.  It was one of those moments that I  will never forget because of the memory of seeing something happen  and feeling absolutely terrible when it did happen.  I placed the bottle cap on my fingers and gave it a snap that would surely send it across the room like a minature frisbee!  It went across the room and directly into Debbie's eye and shattered the glass contact lense.  OUCH!  Her eye would heal,  after a few weeks of treatment and wearing a patch and I would never shoot a bottle cap for  as long as I lived. 
      When doctors started performing the popular LASIK surgery, I remember the hype about such a wonderful break through!  I had several friends get this surgery done as soon as they could and they were thrilled with the results!  The acronym stands for  laser assisted in situ keratomileusis. Refractive Myopia and Axial Myopia are the causes for nearsightedness.  Axial is when the eyeball is too long and the Refractive is when the cornea or the eye lense bends the light coming in too much causing the object to be blurred.  The surgery involves cutting a small flap in the cornea with a laser and then sculpting the cornea so that light comes in parallel  instead of a different angle.  The flap is folded back into place and vision has been repaired!  WOW! 
     Hyperopia is the name for farsightedness and a person can see objects in the distance but due to an eyball that is too short can not see objects that are close.  When the eye focuses,  the focus point for the parallel rays of light is behind the retina and not in front of the retina.  Because so much accomadating is going on to look at nearby objects a person is straining their eyes and eventually with age may experience much strain and headaches from this constant accomodation.  A student that can read the blackboard will have much more difficulty trying to read the book on their desk.
     It is amazing to think of how our brain works and the job that is individualized to each and every organ and tissue in our body and the electrical currents and networks that fire up the neurons and receptors to send and recieve messages to do the most simplist  task.  When these neurons or networks fail then a person would realize just how much our body does simply because of the inconvenience of having that capapbility hindered in any way. 
     In the following video Dr. John Kim gives and excellent explantation and shows exactly what is happening and how vision is corrected.

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