Diagnosis If you have trouble seeing certain colors, an eye care professional can test for a color deficiency. Testing likely involves a thorough eye exam and looking at specially designed pictures. These pictures are made of colored dots that have numbers or shapes in a different color hidden in them.

Stool color is generally influenced by what you eat as well as by the amount of bile β€” a yellow-green fluid that digests fats β€” in your stool. As bile travels through your digestive tract, it is chemically altered by enzymes, changing the colors from green to brown.

Eye color can range from very light blue to brown and may change with age. With albinism, the colored parts of the eyes, called the irises, usually don't have enough pigment. This allows light to shine through the irises and makes the eyes extremely sensitive to bright light. Because of this, very light-colored eyes may appear red in some lighting.

Moles, also known as nevi, are a common type of skin growth that vary in color, shape and size. While most moles are most often harmless, they rarely can become cancerous.

Yellow nail syndrome In yellow nail syndrome, nails thicken and grow slower. This results in the nails turning a yellowish color. Nails affected by yellow nail syndrome might lack a cuticle and detach from the nail bed in places. Yellow nail syndrome may be a symptom of a lung disease, such as chronic bronchitis.