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Home > Archive > Lasik Eyes Surgery > January 2006 > Excess flap tissue after LASIK a source of flap wrinkles (and poor vision).
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Excess flap tissue after LASIK a source of flap wrinkles (and poor vision).
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| Trulytelling@yahoo.com 2006-01-01, 12:56 pm |
| http://www.ncbi.nlm.nih.gov/entrez/...8850&query_hl=1
J Cataract Refract Surg. 2002 Dec;28(12):2146-52.
Mismatch between flap and stromal areas after laser in situ
keratomileusis as source of flap striae.
Charman WN.
Department of Optometry and Neuroscience, UMIST, PO Box 88, Manchester
M60 1QD, United Kingdom. neil.charman@umist.ac.uk
PURPOSE: To calculate theoretically the magnitude of the excess area
between the lower surface of the flap and the underlying ablated
stroma.
METHODS: On the initial assumptions of a nonextensible flap and a
spherical cornea, flap and ablated stromal areas were determined as a
function of myopic correction in the range of 0 to -12 diopters (D) for
typical values of corneal radius (7.8 mm) and flap thickness (160
microm), together with a range of ablation zone diameters (4.0 mm, 6.0
mm, 8.0 mm, and 10.0 mm).
RESULTS: Excess flap area increases with the magnitude of the
refractive correction and the diameter of the ablated zone. For a -6.0
D correction and an 8.0 mm ablation zone, the excess area is nominally
about 1.0 mm(2), giving a potential overlap of the flap at the edge
opposite the hinge of about 100 microm.
CONCLUSIONS; Excess flap area may cause striae because of wrinkling.
Although a nonextensible flap is assumed in the model, any stretching
or contraction due to cutting the flap will be independent of the
refractive correction. Hence, a mismatch in areas must still occur.
This geometric effect may have clinical consequences in optical
aberration, refractive regression, or impaired wound healing.
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| Thats another shortcomming of the flap lasik. When the cornea bed is
lasered away it leaves a gap and the flap doesnt fit right anymore.
This is why some surgeons are moving back to PRK
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| serebel 2006-01-02, 1:10 am |
| True lies forgot to mention that the flap edges are waaay outside the
optical zone.
Ace is still just a parrot for the idiot fringe.
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| The flap covers all of the optical zone. Also when your pupils dilate,
even the edges of the flap is a problem. Why not get PRK instead? Its
more forgiving than lasik, but still not without risks of course...
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| Ragnar 2006-01-02, 11:03 am |
| Is that so? You should call CNN.
Of course that is total nonsense.. and the edge is not square, it is
beveled, and is out of the optical zone. As the flap re-attaches, it
"pulls" the cornea together very slightly, which is a good thing, and
another reason why LASIK is preferable to PRK.
Lastly.. these thicknesses you mention are all less than the thickness
of 3 sheets of typing paper. Furthermore, there is no tissue lost at
the perimeter of the flap. The ablation does not go competely to the
perimeter of the flap. There is only a seam.
On 1 Jan 2006 12:36:33 -0800, "Ace" <acemanvx@yahoo.com> wrote:
>Thats another shortcomming of the flap lasik. When the cornea bed is
>lasered away it leaves a gap and the flap doesnt fit right anymore.
>This is why some surgeons are moving back to PRK
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| Trulytelling@yahoo.com 2006-01-02, 6:07 pm |
| You idiots don't realize that the wrinkling and bunching of the flap
due to mismatch is the problem.
LASIK is not preferable to PRK... it's only advantage over PRK is that
it hurts less initially. It destabilizes the cornea more, gives you
that godawful flap for life, and a poorer visual outcome. Sorry you got
the BAD surgery Ragnar. Time will tell if it is worse in the longterm
than RK.
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| Marshall Cosme 2006-01-09, 1:02 am |
| http://www.321recipes.com/aspartame.html
This is a must read on eye health and maintainance. You may or may not be
affected , but you might be shocked!
Please excuse the interruption , but I thought you may be interested to know
what may be causing all kinds of health problems for yourself or for your
loved ones. I can't seem to get it through to my wife's brain about this
vital health issue, Now she is always saying she is having trouble with her
vision. Gee, I wonder why? I am so pissed off right now, I really want to
slap some sense into her. She has been feeding this poison to my four
children for years after I asked her not too, so you can see why I said what
I said previously, but I would never hit my wife. Why are people ignore what
science brings to are attention about health issues. I am really upset, but
I hope this helps you....since I can't get through to my wife of 16
years.....!!!!!!!!!!!!!!!!
<Trulytelling@yahoo.com> wrote in message
news:1136135414.567661.109800@z14g2000cwz.googlegroups.com...
> http://www.ncbi.nlm.nih.gov/entrez/...8850&query_hl=1
>
>
> J Cataract Refract Surg. 2002 Dec;28(12):2146-52.
>
> Mismatch between flap and stromal areas after laser in situ
> keratomileusis as source of flap striae.
>
> Charman WN.
>
> Department of Optometry and Neuroscience, UMIST, PO Box 88, Manchester
> M60 1QD, United Kingdom. neil.charman@umist.ac.uk
>
> PURPOSE: To calculate theoretically the magnitude of the excess area
> between the lower surface of the flap and the underlying ablated
> stroma.
>
> METHODS: On the initial assumptions of a nonextensible flap and a
> spherical cornea, flap and ablated stromal areas were determined as a
> function of myopic correction in the range of 0 to -12 diopters (D) for
> typical values of corneal radius (7.8 mm) and flap thickness (160
> microm), together with a range of ablation zone diameters (4.0 mm, 6.0
> mm, 8.0 mm, and 10.0 mm).
>
> RESULTS: Excess flap area increases with the magnitude of the
> refractive correction and the diameter of the ablated zone. For a -6.0
> D correction and an 8.0 mm ablation zone, the excess area is nominally
> about 1.0 mm(2), giving a potential overlap of the flap at the edge
> opposite the hinge of about 100 microm.
>
> CONCLUSIONS; Excess flap area may cause striae because of wrinkling.
> Although a nonextensible flap is assumed in the model, any stretching
> or contraction due to cutting the flap will be independent of the
> refractive correction. Hence, a mismatch in areas must still occur.
> This geometric effect may have clinical consequences in optical
> aberration, refractive regression, or impaired wound healing.
>
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