[ramtatatam]

For your eyes - I recommend installing a software that will remind you to give your eyes a bit of relax (years ago when I was on WinXP the software was called EyeCare, when I google for it now there is a plethora of projects so you will need to test what suits you best)

For productivity - what helped me a lot was to block myself on my home router from accessing all distractive web pages I used to pop in every now and then (i.e. playok.com for just one chess game, linkedin, facebook, ycombinator :-) ) - I found that my brain loves to be distracted and it is not that simple to keep focused, blocking distractors helped. Having that said I was also allowing emails in certain hours in the morning and in the evening (no emails during the day).

Also I completely cut on my favorite games (even during the weekend) like HalfLife, CS, starcraft... Was hard to make this decision but in the end appeared to be a great time saver.