Effects of high pixel density on reading comprehension, proofreading performance, mood state, and physical discomfort

Displays with low pixel densities that were common in the 1980s and 1990s were shown to impair visual performance. Display technology, especially pixel density, has tremendously improved in recent years and new technologies allow densities of 264 ppi and beyond. Two experiments were conducted to test whether there are any measurable benefits of high pixel density displays (264 ppi) over moderate pixel density displays (132 ppi). In Experiment 1, participants performed a reading comprehension task on a display with either high or low pixel density. In Experiment 2, participants' speed and performance in a proofreading task were compared using the same displays with high and low pixel density. There were no differences in reading comprehension and reading time (Experiment 1) as well as proofreading speed and performance (Experiment 2) between a 132 ppi and a 264 ppi display. However, subjective ratings of physical discomfort revealed significantly more complaints about headache and musculoskeletal strain in the 132 ppi condition than in the 264 ppi condition (Experiment 2). Reading comprehension, reading speed, and proofreading performance are unaffected by pixel densities above 132 ppi, but reading from high-resolution screens seems to be less exhausting at least subjectively. Thus, while large performance differences cannot be expected, displays with high pixel densities (264 ppi and above) have some advantage over displays with moderate (132 ppi or lower) pixel densities.