Keratoconus and how it bends light?

I've looked and looked on the internet for all the resources on KC I can find, and there aren't that many. I suppose since it is %26quot;rare%26quot;.. 1 in 2000 or so there just isn't that much awareness.



However, I can't wrap my head around how a cornea bends light as it becomes 'cone' shaped. A diagram would be awesome, animation even better.. and further what images would look like with a cone shaped cornea.



It should be fairly easy to illustrate and describe to someone who understands optics, which is why I ask here.



The cornea is normally round, bends light inward slightly then the lens further bends light to a point on the retina.



If this cornea becomes 'cone' shaped how would that light change, and what would the resulting image be on the retina?



I can imagine chaotic,,.. but that isn't very specific.



So any help here would be great. If you have some special hard to find links of illustrations, etc that would be nice as well.



Lastly -- If you are familiar with KC treatment and particular treating one with moderate to advanced KC with RGP's for the first time when they did not have corrected vision before. Would the results from proper fitted RGP's be fairly dramatic for the patient. Would the patient immediately notice a reduction in glare, improvement in contrast,.. and other symptoms that you are trying to correct with an RGP to give the incoming light a better shot at being refracted properly before it enters the other structures of the eye?



Thanks,
Keratoconus and how it bends light?
http://www.keratoconus.com/5.html