There are several reasons why the whites of someone’s eyes might be yellow. Most frequently in people of Caucasian background, jaundice and smoking can cause the whites of the eyes to appear yellow. However, people of African descent have in their bodies a greater amount of melanin, which is the pigment that regulates the color of the eyes, skin, and even the sclera (the white part of the eyes). Because of these increased concentrations of melanin, which are simply hereditary and benign, people of African descent may have eye colors ranging in color from light yellow to brown.
The sclera is the white part surrounding the iris. It is a tough, fibrous material that reaches from the cornea (the clear part at the front of the eye) to the optic nerve found behind the eye. The sclera is the part of the eye that looks white.
For people of African descent, the sclera can range in color from white-yellow to muddy brown. This is a common and harmless condition for people of this ethnicity, and is often mistaken as jaundice. When assessing patients for jaundice, the sclera is the first area to examine. Caution must be taken when examining individuals for jaundice, as yellowness in the sclera may just be a benign melanin concentration.
Various fair to dark-skinned races, such as African-Americans, Filipinos, and many others, have deposits of subconjunctival fat. This means that they have high levels of carotene in the fat of the sclera, which can also mimic the symptoms of jaundice. The fatty deposits grow denser as they get further from the cornea.