Staring at a computer screen in the dark will not cause permanent damage to the eyes, but it can cause eye strain, according to ABC News Medical Unit. Eye strain symptoms may include blurry vision, sore eyes, dry eyes, light sensitivity or headaches.
Ways to avoid eye strain when working on a computer include taking frequent breaks and blinking often, according to CNN. A good way to accomplish this is the "20-20-20" method. Every 20 minutes, focus on something 20 feet away for 20 seconds. Other ways to avoid eye strain are adjusting the brightness to a comfortable setting and keeping the computer screen 20 to 40 inches away from the face.