Eyes light piping has always been a bit of hit and miss. You can see that the toy was designed to have it but often the surface angle of the head, surrounding kibble or size of the eyes/pipe doesn't help it while on the other hand, some can be very successful.
Sometimes Hasbro/Tomy seem to be able to identify a failed light pipe gimmick and actually paints over it rather than keeping the plastic clear just so that the eyes stand out rather than letting it remain dull.