A yellow tint in the white part of your eyes is a serious physical sign indicating a health problem requiring medical evaluation. This discoloration of the sclera, the white outer layer of the eyeball, is medically termed scleral icterus. Scleral icterus is the most visible sign of a broader condition known as jaundice, where the skin and mucous membranes also take on a yellowish hue. The yellowing is not a disease but a symptom pointing to an underlying issue with the processing or removal of a specific pigment from the bloodstream.
The Mechanism Behind Yellowing
The yellow color is caused by the accumulation of a substance called bilirubin, a waste product that forms naturally when old red blood cells are broken down. Bilirubin is produced continuously in the body, primarily from the breakdown of hemoglobin in the spleen and bone marrow. This initial form, known as unconjugated bilirubin, is insoluble in water and must be transported through the bloodstream while bound to a protein called albumin.
The complex of unconjugated bilirubin and albumin travels to the liver, where the liver cells modify it in a process called conjugation. Conjugation makes the bilirubin water-soluble, changing it into its conjugated form, which is ready for excretion. This conjugated bilirubin is then secreted into the bile, a digestive fluid, and travels through the bile ducts into the small intestine to be eliminated from the body, mostly in the stool.
Yellowing of the eyes, or scleral icterus, becomes clinically apparent when the concentration of bilirubin in the blood rises above a certain threshold, typically around 2 to 3 milligrams per deciliter. When the body’s system for producing, processing, or excreting bilirubin is disrupted, the pigment backs up into the bloodstream, a condition known as hyperbilirubinemia. Because of its high content of elastin, the eye’s conjunctiva and sclera have a strong affinity for bilirubin deposition, often making the eyes the first part of the body where the yellowing becomes noticeable.
Primary Health Conditions That Cause Yellow Eyes
The health conditions that cause bilirubin to build up are generally grouped into three categories based on where the problem occurs in the pigment’s metabolic pathway. Pre-hepatic causes occur before the bilirubin reaches the liver for processing, usually involving an accelerated breakdown of red blood cells. Conditions like hemolytic anemia cause red blood cells to be destroyed too quickly, overwhelming the liver’s capacity to process the large volume of unconjugated bilirubin being produced.
Hepatic causes involve conditions that directly impair the liver cells themselves, preventing them from properly taking up, conjugating, or excreting bilirubin. Liver inflammation from viral hepatitis (A, B, or C) can disrupt this process. Chronic damage from alcohol-related liver disease or cirrhosis, which is the scarring of liver tissue, severely compromises the organ’s ability to handle the bilirubin load. Certain medications or inherited disorders, such as Gilbert’s syndrome, can also slow down the liver’s conjugation process, leading to hyperbilirubinemia.
Post-hepatic causes, also known as obstructive jaundice, occur after the bilirubin has been processed by the liver, involving a blockage that stops bile from draining into the intestine. The most common obstructive cause is the presence of gallstones that have moved from the gallbladder and lodged in the bile ducts. Other serious post-hepatic causes include inflammation of the pancreas, known as pancreatitis, or tumors in the pancreas or bile duct that physically compress the pathway.
When Immediate Medical Attention Is Necessary
Yellowing of the eyes should always be evaluated by a healthcare professional, as it signals an underlying disease requiring diagnosis. However, the presence of certain additional symptoms indicates a potentially severe or rapidly progressing condition that warrants immediate medical attention. Signs of urgency include a sudden onset of high fever or chills, which may suggest a serious infection in the bile ducts or liver.
Severe, constant abdominal pain, particularly in the upper right quadrant, combined with the yellowing, can signal an acute obstruction or inflammation that needs prompt intervention. Neurological changes, such as confusion, disorientation, or excessive drowsiness, are also concerning and may indicate liver failure affecting brain function.
A doctor will typically begin the evaluation with blood tests to measure the exact levels of total and conjugated bilirubin, along with liver enzymes. These results help determine whether the cause is pre-hepatic, hepatic, or post-hepatic. Imaging studies, such as an abdominal ultrasound or a CT scan, are often performed next to visualize the liver, gallbladder, and bile ducts to check for any physical blockages like gallstones or tumors.