[quote=@floodtalon]
<Snipped quote by TheWindel>

Henry sure as hell doesn't know that. He isn't even aware that Silver Eyes are a Nexus exclusive thing, he figures there are probably Silver Eye users all over the multiverse who are way more creative than him.
[/quote]

It's not questioning whether or not Eyes exist outside the Nexus, but how reasonable you expect them to be.

For Example; Artillery. 

Artillery is an instrument solely for waging war. It has little to no merit in peace keeping, policing, or any such activity beyond killing enemies at extreme distance. So, you can reasonably expect to find such a tool in; Warzones.

Now that does not negate the possibility of it being outside a warzone, but damn are the odds a helluva a lot lower. 

Now if you look at Silver Eyes, Henry knows two things. One, they are employed by senior soldiers deployed on all sides of the Nexus. Two, they are granted by faction leaders on their whim. 

Therefore, Henry could reasonably conclude that if he had an interest in learning about Eyes, he should have asked one of Hell's leaders who had been granted eyes and seek them out.

Though I don't really see [i]why[/i] he should do this in the first place when he's leaving the Nexus. What more does he need to know when he's on the way out?