I find all these posts writing off the crew as totally disgusting. You don't get to fly UK airliners, never mind large UK airliners by chance. If the pilot was hit by a laser, bad enough that your eye is hurting and you can no longer carry out your duties then you are incapacitated. The QRH on the aircraft I fly says to declare an emergency immediately for a pilot Incap.
So returning to LHR, instead of taking an A340 across the Atlantic and in to JFK seems a hugely appropriate decision. I'm sure one taken after speaking to ops and some Medlink equivalent.
For those calling the crew incompetent or criticising their decision to not continue to JFK, unless you were on the aircraft, directly involved in the decision making process, take yourself back to the shed armchair to continue working on the airfix kit.