In this paper the usability of using polarized filters for reading lamp to reduce disturbing reflected glare was tested based on a within-subject design ergonomic research. Results show that with the increasing polarization degree the subjective rating score decreases, which means that increasing polarization of the optical film reduces the reflected glare. Statistical analysis shows that there is high correlation (0.05 level, 2-tailed) between the subjective rating score on reflected glare and the degree of polarization. An univariate analysis of variance proves that the different evaluation caused by the optical films with different polarization degrees has statistically significant meaning (F=108.4, p<0.001). The results of this research is very useful for optical design of reading lamp, which occupies a big market in China, affecting the visual comfort of huge numbers of readers, such as students and office people.