Anybody tried these ? What is the maximum myopia negative
number they can correct?

excerpt indpendent.co.uk

    The contact lenses that could restore 20/20 vision
You wear lenses while you sleep, then wake up with perfect vision.
Short-sighted Jimmy Lee Shreeve tried it - and couldn't believe his
eyes
Published: 05 June 2007
Once he'd covered the ins and outs of the procedure, Thomas ushered me
to a chair to take the standard eye test, with me squinting at the
shrinking rows of letters and failing miserably to make out even the
top line. The upshot was I have a prescription of -2 in each eye,
which means I can get by without stumbling into things like Mr Magoo,
but can't read vehicle license plates at any distance.

The next step was to sit me in front of some scary, RoboCop-looking
devices to make accurate maps of my eyes and ensure they were suitable
for Ortho-K treatment. The first machine was a split lamp microscope,
which shone a blinding blue light into my eyes, enabling Thomas to
peer into my corneas and search for disease and damage. Neither of
which, thankfully, were present. Thomas also checked that my
tear-production was up to scratch by lightly pressing the skin just
below my eyes. "Tears are the engine oil or lubricant of the eyes, and
good tear production is needed for you to be suitable for Ortho-K
treatment," he said.

After a number of other tests to assess my visual field and explore my
retina, it was time to create a precision map of my corneas. I sat in
front of the corneal topography device and perched my chin on the
chin-rest, which would keep my head still during the delicate digital
mapping process. I then stared - one eye at a time - into the tubular
lens, which looked like some sort of psychedelic tunnel with swirling
bands of orange and yellow light.
Once the mapping was complete, Thomas pointed to the monitor screen to
show me the various images of my cornea that had been produced. The
minute subtleties of each contour and dimension were highlighted in
vivid reds and greens and other shades. This data was then emailed to
No 7 Contact Lenses to make the custom-fit contact lenses which I
hoped would provide me with 20/20 vision again.

A few days later, the lenses were ready. I was given instructions on
their use and how to store and clean them. I then went home for the
big test - my first night with the lenses in. Because I hadn't worn
contact lenses for years, it took me a long time to put them in. I
kept closing my eyes at the last minute, bottling out. When I finally
got them in, my eyes felt sore and uncomfortable, as if I'd got grit
in my eyes. But this passed and I eventually fell asleep.

When I awoke the next morning my eyes felt heavy and my vision was
blurred. " Christ, I've gone blind," I thought, getting into a minor
panic. But when I took the lenses out, I was stunned: my vision was
sharp and focused. I really could see clearly without glasses.

Until that moment, I'd still been slightly sceptical. I thought my
eyesight might be corrected a bit with Ortho-K - perhaps to the point
of being able to watch TV without glasses, but nothing more dramatic.
I didn't expect a return to 20/20 vision - which was confirmed after a
further eyesight test. As far as I'm concerned, it's a minor miracle -
regaining perfect vision without specs or contacts. Had the treatment
been around when I was 13 I might well have left school with some
qualifications. But if I hadn't turned into a rebel because of myopia
I might never have ended up writing for The Independent, or writing
books. Maybe it's a good thing Ortho-K wasn't around then.