Lasik Eye Surgery

i've seen some videos on youtube, and i still can't get hold of how does this operation allow somebody to get a 20:20 vision by BURNING it's retina!


do they always need to take out a layer of cornea to use the laser?



or is it just to perform the "i am putting a contact lens into your eye" surgery?



EDIT: please dont send me to wikipedia!

nikokapo said:

i've seen some videos on youtube, and i still can't get hold of how does this operation allow somebody to get a 20:20 vision by BURNING it's retina!


do they always need to take out a layer of cornea to use the laser?

or is it just to perform the "i am putting a contact lens into your eye" surgery?



EDIT: please dont send me to wikipedia!

Click to expand...

"Burning" the cornea changes its shape. Changing the shape of a lens changes its focal point and characteristics. If you "burn" it correctly, you can make it the shape needed to be able to focus the image correctly on the retina.

Peace,
dave

daguin said:

[quote author=nikokapo link=1213741517/0#0 date=1213741517]i've seen some videos on youtube, and i still can't get hold of how does this operation allow somebody to get a 20:20 vision by BURNING it's retina!


do they always need to take out a layer of cornea to use the laser?

or is it just to perform the "i am putting a contact lens into your eye" surgery?



EDIT: please dont send me to wikipedia!

Click to expand...

"Burning" the cornea changes its shape.  Changing the shape of a lens changes its focal point and characteristics.  If you "burn" it correctly, you can make it the shape needed to be able to focus the image correctly on the retina.

Peace,
dave
[/quote]

Good. Thanks.


I read wikipedia's article (yeah i know) and it cleared all my doubts, but i didnt want to erase the first post because then nobody would understand the thread

I think Cyparagon had lasik some time ago, as I recall.... :-/

So did I...nine years ago. Actually the UV laser beam doesn't "burn" the cornea but because the energy is so high the beam literally breaks apart the atomic bonds in corneal cells. Sometimes lasers like this are called "cold lasers". It's different from thermal ablation.

However, you can still smell something akin to burnt hair as the laser part of the procedure is being done - which makes sense because corneal cells are very similar in composition to the protein that makes up hair and fingernails.

Schrecken_Licht said:

So did I...nine years ago.   Actually the UV laser beam doesn't "burn" the cornea but because the energy is so high the beam literally breaks apart the atomic bonds in corneal cells.  Sometimes lasers like this are called "cold lasers".  It's different from thermal ablation.

However, you can still smell something akin to burnt hair as the laser part of the procedure is being done - which makes sense because corneal cells are very similar in composition to the protein that makes up hair and fingernails.

Click to expand...

That's some very cool info I didn't know!!

FOR ANYONE WHO IS CONFUSED ON HOW LASER SURGERY WORKS READ THIS!!!!

          When you go in to have your eyes fixed by lasers they actually have an alien come from the 14 galaxy named geebajamba and he uses a device that instantly sucks your eyes out of your head into a vacuum and then replaces them with perfect 20:20 eyeballs that have been cloned from the first humans! The bright light you see is just their to distract you from what is really going on! the first person that had this operation done thought the bright light was a laser so he coined the term "laser surgery"

-P.S. i hope this clears things up for anyone confused!

laserlover said:

FOR ANYONE WHO IS CONFUSED ON HOW LASER SURGERY WORKS READ THIS!!!!

          When you go in to have your eyes fixed by lasers they actually have an alien come from the 14 galaxy named geebajamba and he uses a device that instantly sucks your eyes out of your head into a vacuum and then replaces them with perfect 20:20 eyeballs that have been cloned from the first humans! The bright light you see is just their to distract you from what is really going on! the first person that had this operation done thought the bright light was a laser so he coined the term "laser surgery"

-P.S. i hope this clears things up for anyone confused!

Click to expand...

^Notice how you are excluded.

Keep 'em coming!

haha, love the "fail" stuff...


Anyway, lasik involves cutting a small flap of the cornea then reshaping underneath the flap with a laser which destroys the cells (they get cleared out eventually by the body).  Afterward, the flap is put back over the "reshaped" portion, which almost instantly adheres.  

To those who don't know, I'm in medical school, but only finished my 1st year, so I don't have "all" the knowledge of a doctor yet  ;D  But, I am considering ophthalmology (eye surgery) as a specialty, so this stuff is an interest of mine

There's some REALLY cool new technology being used and developed for corrective surgeries.  I personally was evaluated using a machine that actually mapped out my cornea, which could be used with their laser system to customly correct visual abberations, which is very important for those with astigmatism (where the refractive portions of the eye, ie cornea and/or lens, aren't perfect or uniform), as well as being a much better solution those just wearing corrective lenses.

Will there be some new technology apparatus that could take out the aberrations without having the need to remove that flap?

nikokapo said:

Will there be some new technology apparatus that could take out the aberrations without having the need to remove that flap?

Click to expand...

They used to do something (maybe they still do under special circumstances) called PRK - "photo-refractive keratotomy". This didn't have the corneal flap part - they just used the laser alone. The success rate was just about as good as LASIK, however, the recovery tended to be long and very painful. Basically they used the laser to ablate away the upper few cellular layers of the cornea. If you've ever gotten a corneal abrasion from wearing contact lenses (or an accident) that can be really uncomfortable and quite miserable. The PRK was also an injury to the surface of the cornea and from what I have heard, as bad or worse than a corneal abrasion. Many people had to take narcotics during the first 3 days or so to get by.

The LASIK procedure is practically painless because the ablated surface is covered by the flap and the nerves aren't exposed.

The only other option (I suppose this is also still offered) is to actually have a plastic corrective lens implanted behind the cornea to correct vision.

I don't know what else they could do better than LASIK now, that's about the best there is for the near future.

Nice, thanks for answering my Q