Gas Permeable Hard Contacts Scratches
Noke
When gas permeable hard contacts get scratches. What
actually happens to the lens? Can anyone point me to any
site with magnified view of a lens surface? I'd like to understand
what goes on when polishing is done to "remove" the
scratches. The technician said some scratches are deep
and can't be removed. Can these cause corneal ulcers?
How doe scratched lens surfaces damage the cornea?
I'd like to kinda imagine what goes on between the cornea
and lens with scratches and how does the frictions or
contact occurs. Thanks.
Noke
Mike Tyner
forms ridges on either side.
The discomfort of "scratched" lenses comes from the ridges, not the furrow.
Anything that scratches will open the epithelium so germs can penetrate.
Ulcers usually start from broken epithelium and it doesn't really matter
what caused the break. And one good way to get ulcers is to scratch the
epithelium then keep it covered with a nasty contact lens. Normally ulcers
are prevented by the cleaning action of blinking and the antibacterial
lysosyme in tears.
Polishing removes the ridges, along with calcified deposits and other
"protruding" imperfections. To remove the furrow, you'd have to resurface
the lens completely, reducing its thickness uniformly to match the deepest
scratch. That's very difficult to do with a polishing pad; you'd want a
surfacing tool and you'll still break some lenses.
The furrows aren't uncomfortable, especially after they fill up with mucus
and debris and bio-junk. That also creates a warm gooey bed for cultivating
bacteria and fungi.
Scratches that are "too deep to remove" will still feel better after
polishing. They can also be full of polishing compound and ground-up lens
material for a while.
-MT
"Noke" <gad....@yahoo.com> wrote in message
news:7592be83-840f-4bc1...@a9g2000prl.googlegroups.com...
Noke
> It's like the furrow a plow leaves. The material you remove from the furrow
> forms ridges on either side.
>
> The discomfort of "scratched" lenses comes from the ridges, not the furrow.
> Anything that scratches will open the epithelium so germs can penetrate.
> Ulcers usually start from broken epithelium and it doesn't really matter
> what caused the break. And one good way to get ulcers is to scratch the
> epithelium then keep it covered with a nasty contact lens. Normally ulcers
> are prevented by the cleaning action of blinking and the antibacterial
> lysosyme in tears.
>
> Polishing removes the ridges, along with calcified deposits and other
> "protruding" imperfections. To remove the furrow, you'd have to resurface
> the lens completely, reducing its thickness uniformly to match the deepest
> scratch. That's very difficult to do with a polishing pad; you'd want a
> surfacing tool and you'll still break some lenses.
>
> The furrows aren't uncomfortable, especially after they fill up with mucus
> and debris and bio-junk. That also creates a warm gooey bed for cultivating
> bacteria and fungi.
>
> Scratches that are "too deep to remove" will still feel better after
> polishing. They can also be full of polishing compound and ground-up lens
> material for a while.
>
> -MT
>
>
> news:7592be83-840f-4bc1...@a9g2000prl.googlegroups.com...
>
>
>
> > Hi,
>
> > When gas permeable hard contacts get scratches. What
> > actually happens to the lens? Can anyone point me to any
> > site with magnified view of a lens surface? I'd like to understand
> > what goes on when polishing is done to "remove" the
> > scratches. The technician said some scratches are deep
> > and can't be removed. Can these cause corneal ulcers?
> > How doe scratched lens surfaces damage the cornea?
> > I'd like to kinda imagine what goes on between the cornea
> > and lens with scratches and how does the frictions or
> > contact occurs. Thanks.
>
>
> - Show quoted text -
In other words. Even the furrows with polished edge will not do good
and one has to replace the entire lens everytime there is any trace
of scratches in the gas permeable hard contacts?? Thanks.
Noke
Mike Tyner
"Noke" <gad....@yahoo.com> wrote
>In other words. Even the furrows with polished edge will not do good
>and one has to replace the entire lens everytime there is any trace
>of scratches in the gas permeable hard contacts?? Thanks.
Not in my opinion, for what that's worth.
-MT
in message
news:bdfff537-fddc-4769...@u12g2000prd.googlegroups.com...
Noke
> "Noke" <gad.g...@yahoo.com> wrote
>
> >In other words. Even the furrows with polished edge will not do good
> >and one has to replace the entire lens everytime there is any trace
> >of scratches in the gas permeable hard contacts?? Thanks.
>
> Not in my opinion, for what that's worth.
>
> -MT
>
About the furrows that can cultivate bacteria and fungi. Can't
cleaning
the lens each night remove the contents in the furrows? What would
it take to remove it? I ordered a pair of gas permeable hard contact
from a manufacturer. The right side doesn't have scratch, but
unfortunately, the left side has a scratch in the middle. They
polished
it and there is still a trace of the scratch and they won't replace
it.
I can wait a week and order elsewhere but my present contact even
has more scratches (about 20). So I am wondering whether to get
it now or wait one more week for a new lens from another manufacturer.
The decision depends on knowing whether a single furrow is harmful.
Usually what would it take to remove the contents in the furrows like
polishing compound and ground-up lens material? What ingreidents
are polishing compound made of? Is it harmful to eyes? How
about the ground-up lens material. Can it cause scratches in
the eye? Thanks.
Noke
Noke
BTW... letterings such as UV, etc. are often edged on the GP
hard contacts lens itself. Were these lettering made of slumps?
Arethe slumps hollow or did they fill it up with another glass filler?
If hollow. Can they stuck up mucus, debris, bio-junk, bacteria,
fungi, polishing material and/or ground up lens? If so. How
come they put slump lettering when this can stuck up debris?
Thanks.
Noke