The goal of this study is to investigate the possibility of using human eye pupil sizes to estimate visual sensations in office workplace environments. The human body, as a biological mechanism, naturally makes unconditioned responses using the parasympathetic nervous system in multiple physical organs, including pupils in human eyes. Based on this physiological principle, a human body automatically reacts to ambient conditions to minimize any environmental stressful condition. This study adopted this principle as a key factor for analyzing pupil sizes in human eyes and their change patterns to assess each individual subject’s visual sensations while generating various ranges of ambient lighting conditions in an environmental chamber. The chamber is located at the University of Southern California where researchers conducted a series of human subject experiments. The collected data were analyzed using statistical tools for interpreting research findings. The data were grouped by the subjects’ gender, age, glasses-worn condition, and ethnic origin, in order to identify any differences in pupil sizes and change rates, depending on the physical characteristics of each individual. These research findings indicated that the use of pupil sizes to assess a subject’s visual sensations has potential and would be applicable to individuals, regardless of their physical characteristics.