Do not attempt to use an eye mask, turn on the light, turn off the computer, look at beautiful women, eat carrots or blueberries, look out the window, use eye drops, exercise with a laser pointer, or eat spinach, as these methods are shown to be ineffective in solving the puzzle.
The key to solving this level is to directly address the character's eye strain by having him massage his eyes. All other attempts to relax his eyes or provide nutrients are distractions and will not work.