Tears are a natural and constant part of eye health, forming a protective layer over the delicate surface of our eyes. They serve to lubricate, nourish, and shield the eyes from foreign particles. While typically clear and unnoticed, tears can sometimes appear yellowish, prompting questions about underlying causes.
The Basic Science of Tears
Tears are a complex mixture designed to maintain eye health. They are primarily composed of water, but also contain electrolytes, proteins, lipids, and mucins. The lacrimal glands, located above each eye, produce the watery component of tears, while meibomian glands contribute oils and goblet cells produce mucus.
This intricate composition forms a three-layered tear film: an oily outer layer, a watery middle layer, and an inner mucus layer. This film continuously coats the eye’s surface, preventing dryness, washing away irritants, and delivering oxygen and nutrients to the cornea, which lacks blood vessels. Tears also contain natural antibacterial enzymes, like lysozymes, which help fight off infections.
Common Reasons for Yellowish Tears
When tears appear yellowish, it often indicates a change in their normal composition or the presence of additional substances. One common reason is accumulated mucus discharge, which naturally occurs in tears and can appear yellowish, especially upon waking. Increased mucus production may signal mild irritation or the eye’s response to environmental factors.
Infections, particularly bacterial ones, are a frequent cause of yellow tears due to the presence of pus. Pus, consisting of white blood cells and cellular debris, is part of the body’s immune response to fight off bacteria or viruses, as seen in bacterial conjunctivitis. This discharge can range from yellowish to greenish-yellow and may be thick or sticky.
Allergic reactions can also lead to yellowish tears. Allergens irritate the eyes, triggering an inflammatory response that increases tear production and can result in a yellowish discharge as inflammatory cells are released. Environmental irritants like smoke, dust, or pollutants can also cause eye irritation, prompting increased tear flow and a slight yellowish tint as the body flushes them out.
Dehydration can make tears more concentrated, causing them to appear slightly more yellow due to the increased density of their natural components. Certain eye drops or medications applied directly to the eye may temporarily alter tear color. Some ophthalmic solutions contain dyes or active ingredients that can impart a yellowish hue when they mix with the tear film.
When to Consult a Doctor
While minor instances of yellowish tears might resolve on their own, certain signs warrant professional medical attention. It becomes concerning if the yellow discharge is persistent, worsens over time, or is accompanied by other symptoms. These include eye pain, significant redness, or swelling around the eye.
Blurred vision, increased sensitivity to light, or a fever also indicate a need for prompt evaluation. If the discharge is thick, crusty, or has a foul smell, it could signal a more serious bacterial infection. Yellow tears following an eye injury should always be assessed by a healthcare professional.
For infants or young children, yellow tears, especially with crusting or stickiness, can indicate a blocked tear duct or an infection. Seeking medical advice is important if the condition does not improve within a few days of self-care measures. A doctor can diagnose the cause through examination, and in some cases, may perform tests or prescribe treatments like antibiotic eye drops.