Ask HN: How do you reduce eye strain during long computing bouts?

I've been having to work 15 hour days the past week due to a project about to be put into production, and my eyes are killing me. I'm a religious flux utilizer, but I'm curious what other people do to reduce the headache/feeling of 'bulging eyes'/strain after staring at the computer screen for a long time. I've been searching for special glasses to help reduce the eye strain, but know nothing about them.