Combinations of tiny points of light, which are brightnest at the center and siminish in intensity toward their edges. This makes it more difficult for our eyes to maintain focus on these images. instead, our eyes want to drift to a reduced level of focusing called the :resting point of accommodation" or RPA.

Our eyes unwillingly move to the RPA and then strain to recover focus on the screen. This non stop flexing of the eyes and focusing of muscles creates te fatigue and eye strain that commonly occur during and after computer use. Another cause i reduced blinking, When we look at the computer screen we tend to blink less than what we should. This leads to dryness of eyes and burning, itching etc.