My article on Iridian: Iris Scanner <--- has some details that might help.

The only way I could conceive of the overhead being dealt with is a hardware solution but that becomes rather impractical on a large, internet basis (that is, if the intent is to deal with the general populace). This of course begs the question: who is the target audience of this? If it's general population then a software solution would be something to consider or if it's hardware, it has to be cheap as well (cheap, stable and secure -- why should you only have two of three?). If it's business then hardware would be more likely but again, don't want to be too costly. Reality is many companies want security but are finding budgets tighter and tighter. The idea is to get them to use a secure method.