We investigated the effects of implantation damage on the infrared reflectivity spectra of 6H-SiC. Implantation was done with W-ions, at 160 keV and 300 K. The implanted dose ranged from 5x10(13) to 5x10(15) cm(-2). Apart from a well-known intensity decrease and broadening of the reststrahlen band, we evidence a change in the refractive index of the implanted layers. This results in a specific interference regime and, at very high dose, in the appearance of a new line in the LO frequency range. They suggest formation of an effective medium in the damaged part of sample.