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Home > Archive > Lasik Eyes Surgery > July 2006 > Re: Ophthalmology. 2004 Dec;111(12):2175-85. Conclusion is wavefront increases, induce
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Re: Ophthalmology. 2004 Dec;111(12):2175-85. Conclusion is wavefront increases, induce
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| Tom Lucas said:
> Misleading. The measurements are done as a function of area so of course
> there will be more HOAs for bigger pupils - there is more area. However,
> the effects of them will be the same as for smaller pupils because it is
> the density that counts for visual quality.
Thats one factor but the amount your pupil covers is another. The
bigger the pupils, the more light reaches the retina. All distortions
on your cornea reach the retina, for this reason is why anyone with
aberrations see much better in the day or thru a pinhole. I have tried
placing a pinhole in front of my glasses and my best corrected vision
improves half a line on the snellen chart but the increase in contrast
and quality is startling. The letters look so perfectly formed, the
edges so bold and sharp, the blackness so outstanding! Same when I look
at a snellen chart outside in broad daylight then the results are even
better than indoors with a pinhole. I have extremely large 9mm+ dilated
pupils in low light and greater than average aberrations(for a virgin
cornea) so the contrast is slightly muted and small letters or fine
details cant clearly be seen. Ive been told I can gain two lines of
BCVA(as well as increase in quality and contrast) with custom wavefront
z-wave RGP contacts by an optometrist. My corrected vision isnt bad to
begin with, I have none of the "effects" people with bad lasik have.
> No it wouldn't. See above.
My vision certainly is sharper when my pupils are small
> The intention is reduction but elimination is a stretch target. All
> clinics will offer Lasik to reduce dependency on glasses but none will
> promise to eliminate them. Minification might possibly account for some
> of the improvements in BCVA but the procedure often improves the eye
> too - that is just another benefit of Lasik.
True but some people find they are glasses free till presbyopia takes
over or till their eyes change. A reduction in glasses dependancy and
not being "blind" without glasses is the 9 yards, elimination of
glasses is the 10th yard. Lasik gives vision up to what
glasses/contacts give. No one claims super vision with todays laser
technology. Even RGP contacts which give the best possible vision
rarely gives better than 20/15. Adaptive optics are large bulky
machines with thousands of mirrors which cancel out your aberrations
and simulate truly perfect vision. When this technology advances that
adaptive optics are small enough to fit on wavefront glasses, ill wear
it for 20/10, 20/8 or even better vision depending what my retina is
capable of!
> No, no, no. Ecstasia is very rare and Lasik patients statistically have
> a lower chance because they are screened before surgery. Regression does
> occur sometimes but not through corneal bulging.
That is true and I have asked for clarification when corneal bulging is
mentioned. I believe they mean the intraoccular pressure pushes the
thinned cornea outwards a bit then stops. Other factors could be
thicker epithelium, axial myopia in younger people(especially college
students)
> You are bashing Lasik or at least purposefully putting it in a bad light
> by misrepresentation of facts.. What you are presenting are facts but
> they are to be taken in a different context - you can't use unrelated
> statements to construct a integrated premise. I.e. There is a very
> slight risk of ecstasia after Lasik and some people regress over time
> therefore the regression is due to ecstasia induced by Lasik is not a
> valid argument. Similarly saying bigger pupils have more HOAs and HOAs
> are bad for vision therefore big pupils have worse vision is faulty too
> because important detail has been left out such as the method of
> measuring the severity of HOAs.
The risk of ectasia becomes neglecable if you keep 300+ microns of
cornea. That is what many surgeons aim for now. If cornea too thin, PRK
or IOLs are offered. Bigger pupils do give worse vision, I speak from
experience with my huge pupils
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