The casue of this is the flash is too close to the lens, using hotshoe flash, most of the time don't have this problem, but Caucasians (lighter eyes) are more prompt to this problem than Asians (darker eyes). that's why flash bracket is very common use in Western countries.
if you using compact camera, built in flash on SLR or DSLR, try to switch to red eye mode, but not 100%.
Hope this help.