So from the various reports he was attacked by a metal bar with a spike on it, he had severe head injuries and if he survived would be blind.
From the above i'm assuming he was blinded by the spike being used to target his eyes and blind him 
I'm wondering if he was 1st hit over the head to drop him to the ground and then had his eyes fucked up or whether his eyes were targeted 1st and then he was generally beaten 
What i'm really wondering is whether he was in much pain and knew / was aware of what was happening to him during the attack, it's clearly a savage attack that under normal circumstances i'd be appalled by but in his case i'm hoping he knew that he was being dealt with and suffered at least for a while
I've seen/heard stuff that suggested that the injuries were so bad, with so much blood flowing, that the POs thought he was dead on the spot. It's also been suggested that the "metal for with a spike" was some kind of tool issued to the perpetrator by the prison, as they were both on some kind of work to do with waste recycling.

I almost hate myself for thinking this, but having a metal spike forced through your skull and staying there must cause massive pain, which he must have been aware of.
No doubt there will be a massive enquiry by both the Police and Prison Service, which will make their way to the media one way or another.