[The effect on the shape of color soft contact lens caused by pigments].

PURPOSE: To investigate the effect of the pigments in colored soft contact lenses (SCLs) on their shape and physical properties. METHODS: To make a comparison between clear SCLs and colored ones, we used SCLs made of the same materials and the same size and power, and are approved by the Japanese government. The shapes were evaluated in a saline solution by using a CL image viewer, and the sagittal depth was measured. In addition, we made fragments of SCLs and evaluated their shapes. The case we investigated the fitting pattern of the clear SCL was completely different from that of the colored ones on the same eye. Both lenses had the same parameters, were made of the same materials by the same manufacturer. RESULTS: There were significant differences in the sagittal depth between the clear and colored SCLs. When the fragments were made, the shapes of some colored SCLs reversed. This phenomenon was not seen in the clear SCLs. CONCLUSION: The shapes and fitting pattern of colored SCLs sometimes became different from the clear ones. Colored SCLs should be prescribed by ophthalmologists and checked regularly for problems.