It is necessary to study the effect of various process conditions on the final injection-molded parts for producing precision injection-molded products. In the present paper we have focussed on the effect of process conditions on the optical anisotropy remaining in the disk-shaped product by varying the process conditions systematically. Polystyrene and polycarbonate, which have different photoelastic properties, were used to mold the disk of the diameter of 10.16 cm and the thickness of 2 mm. By examining the gapwise distribution of birefringence and extinction angle the effect of holding pressure on the structure of optical anisotropy, especially, on the value of inner two birefringence peaks has been shown clearly. Furthermore, structural difference in birefringence data of two different materials have been found which came from the differences in optical and physical properties. This experimental data could serve as a basis of testing the computer simulation program to predict the residual stresses and optical anisotropy distribution in the final injection-molded products.