Eye Too Flat?

[rustyisle]

I went to a third doctor for an opinon Tuesday and was told that he could not perform Lasik/Lasek on me because my eye was too flat. I asked one of the two doctors who said they could work on my eyes about this and was told:

I agree that you should not have Lasik, you are a candidate for Lasek but at the upper limits. I would not fault anyone for saying "no", and my "yes" would be cautious. Your RX is at the limit most would use as a cut off.
As far as being too flat this is more of a judgement call. Your corneal curvature (K readings) are 41.5 diopters. Surgery will flatten it down to an estimate 36. Some docs use 37 as a cutoff, but this is strictly arbitrary. My cutoff (as well as most Lasek docs) is 35.
Some studies have shown that reducing the K's too much can affect quality of vision by inducing aberrations (difficult to access by Snellen acuity alone).

Anyone know what he means by aberrations? Anyone have experience with this 'flat' of an eye? Any help would be appreciated as I'm still trying to make the decision.

[LasikExpert]

The cornea is a prolate shape, like the tip of an egg. The prolate shape provides optimum forward vision. Vision correction surgery for myopia (nearsighted, shortsighted) flattens the center of the cornea to change the focus of the light entering the eye to be at the retina.

If the cornea is too flat the light rays are focused at the retina, but may be spread too wide. They are focused, but not tight. This can reduce contrast sensitivity and cause degradation in vision quality.

What the doctor wrote is accurate. You are at the margin where some doctors would decline you and others would do surgery with extra informed consent about the concerns.

Aberrations are simply imperfections in vision. Myopia is an aberration. Higher order aberrations are commonly measured with a wavefront diagnostic device and presented as Zernike polynomials with names like coma, trefoil, and secondary astigmatism.