The College of Optometrists

if the lens appears to be riding too high or too low it is ok to say increase the total diameter as centre of gravity would be further back in the lens and help to centre it? How can i tell if the lens is lid attcahed or just riding high - i've just been taking top lid out of the way and if lens falls i am presuming lid attachment!? worried about assessing the RGP. Failed on that last time. Any goog hints?

A flat lens will ride high if the lid grasps it. You will see pooling under thelower edge in that case. Increasing the OD will tighten the fit by increasing the sag. If the OD is correct you could just tighten the BCOR.

If RGP lens is riding to high then you can increase the lens thickness as it will result in a lower position on cornea. Alternatively INCREASE the radius of the lens.