My mother has had 2 rounds of chemo so far for her metastatic colorectal cancer with 5 FU, irinotecan and cetuximab, and the last couple of weeks has experienced 3 episodes of a strong pain in her right eye which has then lasted about an hour. The oncologist yesterday suggested that it could due to the 5 FU, as this can cause headaches, and initially to get checked at the opticians. My feeling/ fear is that it is due to metastasis, but i was wondering if anyone else had had similar symptoms as side effects from chemo? (Really hoping...)