Your changed color of eyes may be affected from the constipation. You should go to see the doctor to have a full check on the eyes to see whether you get the macular degeneration. You should have the good rest now, drinking more water and taking more food with vitamin C to moisture your eyes. You should not smoke or drink these days.
So sorry to hear that you are suffering from yellow eyes. As a matter of fact, it is mainly resulted from aging, inborn lack of immune systems, and other eye problems. It has little connections with constipation. However, it is advisable for us to take care of every part of our body. I suggest that you go to the hospital for medical checkup to see where went wrong, and take actions against your problem.
Well, generally speaking, constipation is a symptom of a poorly functioning digestive system. And according to some experts, when it occurs, there will be some other symptoms occurring in your body. For example, lack of energy, bad breath can be possible. Also, it will just affect your eyes, leading to some eye problems, such as dark circles under the eyes. And in some cases, yellow eyes can be possible too. So I have to say that it is kind of normal for you to have yellowing in your eyes. And for your situation, you can drink more water, for increasing the amount of water we drink will reduce the risk of the stool becoming too dry. And that can just relieve yellow eyes.