Rigid Contact lenses
Rigid (hard) gas-permeable (RGP) contact lenses can greatly improve vision when glasses are no longer effective.
These are the most common method of improving the vision for patients with Keratoconus. Supported by the natural tears in the eye, the irregular surface of the cornea is reshaped allowing for better vision.
The development of special keratoconus RGP contact lens designs has increased the usage of RGP lenses over the years. However, RGP contact lenses cannot be worn by everyone. Many people will experience unacceptable discomfort. Therefore they are only partially successful, especially for patients with low production of tears, as an adequate supply of tears is needed to provide adequate lubrication to buffer the RGP lens.
Piggyback or Hybrid lenses
If RGP contact lenses are not tolerated, piggyback lenses are sometimes used, where the hard contact lens is placed on top of a soft contact lens making wear more comfortable.
This superimposed method, although more awkward, may sometimes be better tolerated than an RGP contact lens alone.
Another option is the use of a hybrid lens (hard centre and soft edge), which can be an alternative solution.
In very advanced cases of keratoconus, a well fitted scleral contact lenses may offer visual correction.