Even though injection molding technology has been developed for many years, it is still needed to study the effect of processing conditions on the final properties of injection-molded parts for producing precision products in optical field. The optical anisotropy, i.e., birefringence, is a significant factor which affects the function of many optical components. In the present study, we have focused on the effects of packing and compression processes on the birefringence structure remaining in the disc by examining the gap-wise distribution of birefringence and extinction angle. As a result, two extra birefringence and extinction peaks near the center in thickness direction showed the effect of packing pressure, which came from the extra flow during packing stage. Furthermore, more uniform birefringence distribution was found in injection/compression case than in conventional injection-molded case. Depending on the process condition, even the reversal flow was found from the distribution of extinction angle in injection/compression case. Finally, graphical representation technique of optical refractive indicatrix was suggested to show the difference of final birefringence structure for different process types.