What causes of yellow eyes?

Jaundice. This is the buildup of bile pigments which is the result of liver or gall bladder disease. Incomplete excretion of these pigments stains the sclera yellow. With resolution of the problem, the white of the eye will return to normal. Good idea to see your gastroenterologist or primary care doctor soon!
Yellow eyes. This can be normal or due to many issues such as liver disease, dehydration, or other problems. Try frequent artificial tears, increasing fluid intake, and getting your liver enzymes checked. If no improvement, see an eye doctor.