Ortho-K - Max correction zone

Hey all, I am back again. Just looking for another quick pointer with
a few more facts.

Ortho k patient, using euclid lenses.
history: Experiencing glare at night.
Cause: Correction zone is not large enough

I have had a second opinion and additional topography shots taken via a
doctor that supports Paragon CRT, just to get a true alternate
position. I am currently maxed on the euclid correction zone, and the
paragon consultants state that their max is similar. Fit is "good" and
centration is spot on when I sleep in my lenses. They do decenter a
bit towards the medially? (towards my nose) if I wear the lenses while
awake, but since I only wear them while sleeping it is not an issue.

So I am seeking the wisdom of the crew. My iris's measure 6.5mm in
moderate to dark light and my lenses are 11mm with a 6.6 correction
zone.

Anyone know of a lens system that can correct a larger zone? Base
prescription is -2.25/-2.5 with a slight astigmatism in one eye. Well
within the limits (-.25)

Please: no responses if you are not a doctor or have valuable
information about OK.

BTW: BE Retainer states that their curve "seems" to treat a larger
area, but unfortunately there are no doctors supporting the BE system
in my area. Anyone have any first hand knowledge?

 

Can nobody design a custom lens for you to go another 0.5mm larger?

DrG

 

Both paragon CRT and euclid state that 11.000/6.600 is the max that
their lenses can go and remain useful, even with a fairly low beginning
prescription.

(11.000/6.600 0.000(1.000) 8.590 and 8.430 in the other eye if it
matters.)

 

Here's a link to a previous discussion of this in sci.med.vision.
http://makeashorterlink.com/?M37D15ADD

DrG

 

I read through that and it seems that the formulas are saying 7mm is
possible, but that it may fade too quickly or not correct enough even
with my prescription.

That being said, the manufacturers (euclid and paragon) both state that
they only go up to 6.6 and that more would not help in my situation.
This leaves me at a bit of quandry and what I am curious about is more
on the other brands that are available with different curves. Being an
end user the information is very difficult to come by.

Scot

 

Indeed, it will. The manufacturers have to have their designs approved
by the FDA, and so cannot veer from their designs. Therefore, you will
have to seek out a private OD who will go out on a limb for you and
design a custom lens, and you will have to give him your consent to
experiment.

DrG

 

Are yours too small a zone? My orthoK practitioner said he can go up to
8mm zone!
If my math is right, an 8mm zone would correct up to -2 diopters. Youd
be 20/25 instead of 20/20 then.

 

Ignore the retard here, he has no OK doc, has no education, lives in
his mommie's basement, no job, and no future.