Well, yes, constipation can lead to red eyes. First, in common, constipation occurs when bowel movements become difficult or less frequent. According to some researches, common symptoms and complications include nausea, diarrhea, breathing difficulty, nausea and vomiting, fever, pneumonia, sensitivity of the eyes to light may occur. And when you suffer high fever because of constipation, your blood pressure will be high too. At that moment, it is possible to have red eyes. So just be careful about it. And when it occurs, jus go and see the eye doctors.
Yes, it is possible for you to get red eyes because of constipation because of the disorder of the inner body. When you get the constipation, your intestines and stomach will not work in the right way. You may lack water in the body. Your eyes may feel dry. That is why you get the redness in the eyes. You'd better use some eye drops to release the symptom.
Well, it seems that there is something wrong with your health. As a matter of fact, it is true that constipation would give rise to red eyes or something bad with your eyes, because your body is an highly intergrated system which are interconnected with different organs and parts. Anyway, you could try to get more vitamin pills and vegetables, also, try to get some eye drops with the doctor's help.