I'm sorry to hear about your keratoconus, but I don't think you can definitively infer that Seroquel is the cause. I have not read of any studies that indicate a link between the drug and KC. There definitely do seem to be genetic factors for developing kerotoconus, but from what I have read only 13-15% of people who have this condition have a family history of it. The exact causes are unknown, but I have read that environmental and even the endocrine system could play a role.
There are some new treatments on the horizon which may help you, including a procedure called corneal collagen crosslinking, which has the possibility of arresting the progression of the condition, eventually allowing the cornea to be reshaped with laser surgery. You may have seen these studies. If not, and you are interested, send me a personal note and I can provide you with links to a couple of websites that may interest you.