atulg wrote:I am now trying to determine how the doctors come up with the soft spherical lens number based on the prescription.
It's often said that prescribing contact lenses for KC is more than an art than a science. There is a lot of trial and error involved in obtaining an optimum prescription for contact lenses. Which can be incredibly frustrating. If your old prescription is not as good as your old one go back to the optician and explain your problem. Be aware that sometimes a comfortable lens with good vision can be an unhealthy fit so should no longer be worn (although this probably applies more to RGPs than soft lenses).
Prescriptions for contact lenses are quite different from those for glasses. My right eye is -13.00 sph - 1.75 cyl but my RGP is -10.25.
Do look at Information Sheet 4: Getting the most out of a contact lens appointment
which can be found here:
https://www.keratoconus-group.org.uk/in ... on-sheets/You may also find it useful to view a couple of videos by optometrists talking about KC and contact lenses.
Videos from the 2016 conference can be found here:
https://www.keratoconus-group.org.uk/in ... -videos-2/and those from the 2018 conference here:
https://www.keratoconus-group.org.uk/in ... deos-2018/Lia