I'll adress both posts with a general one.
If you are going from a period of wearing an RGP lens to a soft lens, there will be a period of demoulding, this is because the rigidity of the RGP lens depending on fit can either comlpress the cornea so making it flatter so during demoulding the cornea will steepen sligtly or drawn out slightly by the RGP lens making the cornea steeper, so the cornea needs to settle back to a flatter shape. So basically there is an initial period where the cornea returns to a 'more natural' keratoconic state.
As this process happens, the cornea will 'bounce a little' and the period of demoulding is often proportional to the time RGP lenses were worn, so a change of prescription may be needed. For me after 4 years of RGP lens, it took about 9 months for the major changes to take place with minor changes over the next 3 to 6 months. Unfortunatly we are all different so the time it takes will differ for each person.
The Kerasoft 2 in the world of soft lenses is now old technology and alot more rigid and thicker and for me never gave the level of vision due to the limitations of its design. It also has less oxygen permeability than an RGP lens and I found that it was this that was giving the blurred vision.
This was superceeded by the Kerasoft 3 which was intended to be a silicon hydrogel version of the Kerasoft 2 but eveloved to something more and now the Kerasoft IC which is a far more advanced because of the way the optics are applied and the way it can be tailored to the eye. I have used both leneses and found we would get perfect vision but over time through the demoulding process, the vision would drop off from 6/6 to 6/12 which was sill sufficent to drive, so only a few changes of prescription were needed.
The Kerasoft IC has no mouldnig effect on the cornea, the mistake many optoms make when fitting these lenses is if they see the lens is rotated off but not moving they assume they can compensate for this which is completly wrong and is emphasised in the training. If the lens is roated beyond a certain point this may be compensated for at the fitting but once transposed to the final lens, vision will always be off becaus I think if I recall correctly the lens is too tight so no guarnetee it will settle in this position again. The lenses are basically weighted using a prism I think so they are in the correct orientation. The other thing that often happens is that the optom fits a lens so that it moves like an RGP lens and then the fit is too loose and eveytime you blink the vison goes off.
There needs to be some movement to help the flow of tears round and under the lens, the rotation needs to be within set perameters and above all comfort, get these basics and you are well on your way to having a good if not excellent fitting lens and a good possibility of excellent vision.
My right lens is -8.00 and the left -4.75 with additional querky bits to the lens to accomodate the fluctuations in the graft margin and at my hospital check up on Thursday 14th Feb I was getting 6/5 in both eyes which is better than when I was in RGP lenses. Gave up on RGP's five years ago and had the Kerasoft 3's as soon as they came out and the privelage of Kerasoft IC's while they were being developed and still on the Kerasoft IC lenses.
Take a look at the Kerasoft web site, there is lots of useful information for both patient and practitioner;
http://www.kerasoft.co.uk
