It could mean several things. You could have an underlying systemic disease such as jaundice or hepatitis C. If you just see yellow deposit-like bumps on the whites of the eyes, it is probably a pinquecula. Pinqueculas are fatty deposits that build up on the scleral tissue for added protection from the Sun's uv rays, wind, dust etc. They are harmless unless they grow too far onto the cornea. You should have them examined by an eye doctor, if that is the case.