The eye color changes when the blood pressure changes. When your blood pressure changes, it makes the pupil smaller and reflect more light, then eyes can appear different colors. When you cry, the blood begins to move out and goes to your eyes. Therefore, your eyes will easily get blood shot. Moreover, if there is extra blood in your eyes, your eyes will appear green. So if you find your eyes change color when you cry, you needn't to worry.
If it changes into redness, it is normal. Or else, it is not normal. When you cry, the eye nerves will be intense and there may be the bloodshot in the eyes. And the crying will cause the eyes muscles to be tight. You'd better have some protection after the crying by using the hot cloth to cover on the eyes to release the redness.
Well, yes, of course, it can be normal. You should know that your eyes color can change with different emotions. Generally speaking, they become Light grey and light blue, when you are crying, sad, concerned, worried. And when you are clam, your eyes' color can change to grey. According to the research, Color change is caused by blood pressure. If you embarrassed or excited, for example, your blood goes faster through the veins and if you're calm your blood then goes slower. This is just like how your face becomes red when youâ€™re embarrassed, your eyes change color. So it's very normal to have this situation. And you should not be too worried about it. In my opinion, controlling the emotion is a good way. Of course, you should not cry too much, or it can be harm to your health.