Flat cornea

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Flat cornea

Postby arilink » Wed Sep 15, 2010 11:35 pm

I have wanted to get my vision corrected for a long time now. Lately my eyes are not the best friends with my contacts and I hate to wear glasses. I am 26 and in general good health. My eyes get dry at times and I do understand that they would be even dryer after lasik.
I went and got a consultation with a very reputable doctor in my are and he said that I would be a good candidate for lasik. I was very excited to hear the good news.
Because my vision is very important to me I decided to get a second opinion just in case.
The second Doctor told me that he does not recommend Lasik for me.
He said that because my cornea is too flat that I would not be a good candidate. My cornea flatness is approximately between 38.7 to 39.6 with an average of 39.2. My prescription is -3.75 in both eyes. The doctor said that the cornea is thick enough but that the problem is flatness.
I am thinking about getting a third opinion.

What do you think about my situation? what are my risks and what should I do?

Please help,
Thank you
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Joined: Wed Sep 15, 2010 5:37 am

Re: Flat cornea

Postby LasikExpert » Tue Oct 12, 2010 9:20 pm

Lasik corrects myopia (nearsighted, shortsighted) vision by removing tissue in the center of the cornea, thereby making it flatter. For most people this results in a reduced need for corrective lenses like glasses or contact lenses. In your case, you may be risking poor vision quality. The issue is prolate vs. oblate.

A prolate object is one that is has a sharper arch at the center and gradually less pointed toward the sides. Think of the end of an American football. An oblate object is one that is flatter in the center with sharper curves toward the sides. Think of the top of a hamburger bun. Human eyes are naturally prolate.

Animals who are predators have eyes that are set forward and more prolate corneas. This system provides optimum forward vision quality. An eagle has very prolate corneas with excellent forward vision. That is how an eagle can see a frog from 500 feet away and swoop down at 50 mph to grab the prey. Animals that are prey tend to have eyes set back and more oblate. This system provides optimum peripherial vision quality. A frog trying to not be an eagle's dinner needs to see the eagle coming down from behind at rapid speed to make a jump into the pond. Frogs don't have very good forward vision, but they are more likely to survive if they can see what is coming after them, even if they cannot see it well.

Lasik makes the human cornea more oblate (frog) and less prolate (eagle) by flattening the center of the cornea. For normally curved corneas this is not an issue. Even very myopic people can have Lasik without loss of forward vision quality. A flat cornea, however, is a different matter. Even if peripherial vision is improved, human activities require forward vision (even if we are not commonly hunting frogs). A cornea that is too flat after Lasik can reduce vision clarity that may not be improved with glasses or contact lenses.

Newer lasers attempt to create a more prolate ablation pattern on the cornea, but the net effect in all circumstances is a flattening of the center of the cornea.

The second opinion surgeon told you, essentially, that you will not be giving him a few thousands of dollars. That is a pretty good reason to believe the second surgeon. If you seek a third opinion, seek it from a corneal specialist.
Glenn Hagele
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