Yellow eyes, medically known as icterus or jaundice, are a sign of a serious underlying health problem, not a disease itself. This yellowish discoloration occurs when a specific substance builds up in the bloodstream, indicating a malfunction in the body’s internal waste management system. While the symptom can be subtle initially, any noticeable yellowing of the eye tissue requires prompt medical evaluation. The change in the eyes is frequently the first sign to become visible, often before yellowing of the skin.
Where the Yellowing Appears
The yellow discoloration is located in the sclera, the dense, white outer layer of the eyeball. Technically, the color change occurs in the conjunctiva, the thin membrane overlaying the sclera, a phenomenon called scleral icterus. The conjunctiva’s high elastin content attracts the yellow pigment, making the eyes a primary site for deposition. The hue can range from a pale lemon color to a deeper orange or even a greenish tint in severe cases.
To check for this change, examine the eyes in bright, natural light, as artificial light can mask the discoloration. Pulling down the lower eyelid allows for a clearer view of the lower sclera. This discoloration becomes noticeable when the pigment levels in the blood reach approximately three times the normal limit.
The Role of Bilirubin in Yellow Eyes
The mechanism behind this discoloration involves bilirubin, a yellowish waste product of the body’s normal processes. Bilirubin is primarily formed when old or damaged red blood cells are broken down, specifically from the degradation of heme. This initial form of bilirubin is water-insoluble and is transported through the bloodstream bound to the protein albumin.
When this complex reaches the liver, the organ performs conjugation, chemically modifying the bilirubin to make it water-soluble. This water-soluble form is incorporated into bile, a digestive fluid that is ultimately excreted from the body, mostly through the stool, which is why stool has a brown color. Yellow eyes occur when this process is disrupted, causing an excess accumulation of bilirubin in the blood (hyperbilirubinemia), which then deposits into tissues like the conjunctiva.
Health Conditions that Lead to Yellowing
Conditions causing bilirubin buildup are generally categorized based on where they disrupt the normal processing pathway: before, during, or after the liver.
Pre-Hepatic Causes
Pre-hepatic causes involve an excessive rate of red blood cell breakdown (hemolysis), which overwhelms the liver’s capacity to process the resulting bilirubin. Examples of this overproduction include conditions like hemolytic anemia, where red blood cells are destroyed too quickly, or the rapid breakdown of a large hematoma.
Hepatic Causes
Hepatic causes involve damage to the liver cells themselves, impairing the organ’s ability to efficiently take up and conjugate bilirubin. Common conditions affecting the liver directly include viral hepatitis (A, B, or C) and long-term liver scarring known as cirrhosis. Alcohol-related liver disease and certain drug-induced liver injuries also interfere with the liver’s metabolic machinery.
Post-Hepatic Causes
Post-hepatic causes, also called obstructive jaundice, occur after the bilirubin has been processed but cannot be properly excreted. This is typically due to a physical blockage in the bile ducts that transport bile to the small intestine. Frequent causes of this obstruction are gallstones lodged in the common bile duct, or external compression from tumors, such as those originating in the pancreas.
When to Seek Medical Attention
The appearance of yellow eyes requires prompt consultation with a healthcare professional to determine the underlying cause. Immediate medical attention is necessary if the yellowing is accompanied by severe or sudden symptoms.
These urgent signs include the sudden onset of severe abdominal pain, especially in the upper right quadrant, high fever, confusion, or persistent nausea and vomiting. Changes in waste products are also indicators of a serious issue, such as very dark urine and stools that appear unusually pale or clay-colored.
Diagnostic evaluation involves a physical examination, blood tests to measure bilirubin levels, and often imaging techniques like ultrasound to visualize the liver and bile ducts.