Orthokeratology

"Ortho-keratology, or Ortho-K, is the use of specially designed rigid gas-permeable (RGP) contact lenses to alter the shape of the cornea in order to reduce or correct myopia (short-sight). It can also be effective with low degrees of astigmatism.
According to the British Orthokeratology Society the procedure works best for people who are short sighted up to about –5D of myopia with no more than –1.50D of astigmatism.
To see if you fall within these categories look at your most recent spectacle prescription. If the ‘Sph’ box is –5.00 or less and the ‘Cyl’ box is –1.50 or less you may be suitable for orthokeratology and if you are interested we recommend that you consult your optometrist to discuss this procedure. Even if you are within these prescriptions, some people are more successful with orthokeratology than others.
If you are long sighted (up to +3 D) or more short sighted (up to –10D) you may be suitable for orthokeratology but this will be more complex than for the prescriptions above.
If you are over the age of about 45 and need bifocals/varifocals or a separate prescription for reading (or take your spectacles off to read) you must realise that if orthokeratology is done in both eyes this will affect your reading prescription too. If you are treated so you are not short sighted for distance and you would previously have removed your distance spectacles to read you will find that when your short sight is treated you will need to wear reading spectacles instead. You may find that this is more inconvenient than simply removing your spectacles to read. Your optometrist will advise you about this in more detail, and one of the advantages of orthokeratology is that it is reversible, so if you don’t like the effect you can return to the status quo"