Currently there is a considerable amount of research and innovation into hybrid lenses with the Synergise brand expanding rapidly over recent months. They are an excellent remidy for high levels of astigmatism.
They work in a asimilar way to the mini-scleral designed lenses where, the corneal surface toricity (astigmatism) is counteracted by the tear lens formed from the cavity between the contact lens back surface and the cornea. This reduces the need for highly powered lenses, meaning that thay can be made thinner and consequently will be more comfortable.
They also have the advantage of the soft lens skirt. This will aid centration of the lens on the cornea, particularly in very astigmatic/advanced kertaoconus whilst also improving comfort and lens wettability.
In my personal experience i have found this modailty very useful for those with PMD.
Due to thier design, however, the amount of lens parameters are limited, therefore, can berendered unsuitable if there is any residual astigmatism, ie not corrected by the tear lens, or if the diameter of the lens needs to be changed in eyes with a large cornea.
Pro's
Good comfort
Gives good vision even in the most complex cases
Similar to piggy-backing but less complicated
Con's
Insertion and removal difficult
Oxygen permeability can be an issue
Lens dehissence (breaking of RGP/Soft lens bond can occur