Features unique to specific lasers

[beingbobbyorr]

Glenn --

Some of the doctor's literature I've read claims that the key feature of the Alegretto Laser is that it compensates for what they call the “cosine-offset” effect: it's calibrated for the scattering & reflections of energy when the beam is “off boresight” (at the periphery of the cornea). i.e., it doesn't take shortcuts when it comes to (correctly) burning the whole surface of the cornea .... not just the center.

I find it hard to believe that in 2008 (13 years after Lasik got FDA approval) that only one (out of the 5 manufacturers) Laser models can boast of doing what appears to be elementary engineering. To your knowledge, is this truly unique to the Alegretto or do other manufacturers do it, but under different terminology to avoid patent infringement?

Likewise, the Visx S4 talks about doing "Iris Registration". What is that, and is that really unique to their model?

Thanks.