1. Dim the lighting - the screen lighting, that is: eyes get fatigued with high contrast, so adjust the brightness to mid-level.
2. Gaze ahead - humans were engineered to spot prey at a distance, so looking at close range for hours is unnatural. Make sure to look 20 feet away for 20 seconds every 20 minutes.
3. Stretch and massage - a few times a day, close eyes and look up, down, and side to side, then gently press lids. It relaxes muscles - and just plains feels goo