I guess No special foods will promote the whiteness of the eye. As we age ,the color of Scleral become more dark .when you see a child ,you will find the color of her sclear is brighter than older man .also it is decided by our genetics and skin colour. Pink/red sclera can be a sign of disease, allergy, fatique, or irritation.
As far as i know, there is no such foods that can promote the whiteness of the sclera. I just wonder why you have such idea? The sclera in the eyes should be white itself. Of courses, there is a situation that your sclera maybe yellow because of liver problems. If your sclera is yellow, you'd better see a doctor.