Yes, you should contact your Doc. The term that is used for the yellow discoloration on the whites of your eyes, is call icteric. It's also known as jaundice,which can be caused by several different things.Your Doc will need to order some blood tests. It could be that your bilirubin is elevated. Here is a test explanation: Bile, which is formed in the liver, has many ingredients, including bile salts, phosolipids, cholesterol, water, bicarbonate, and bilirubin. Due to the breakdown of red blood cells,( a normal occurrence ) bilirubin is processed. An elevated level can be caused by gallstones. anemia, and several other things. Any recent injury? Are you of African American descent?? I ask this because Sickle cell anemia, which is a genetic abnormality among African Americans, can be a cause for the yellowing of your eyes. I am not certain if colon cancer would be the cause but, according to my references, that is not listed. I hope that this helps. Contact your Doc.
Medical Professional, RN. Internal Medicine.