When sickness strikes, many people notice an increase in watery eyes alongside other common symptoms like a runny nose or sore throat. This often puzzling symptom is a frequent experience, leaving individuals to wonder why their eyes produce excess tears when unwell. Understanding the body’s defense mechanisms can clarify this common response.
The Body’s Tear Production and Protection
Tears are far more than just a byproduct of emotions; they play a continuous and essential role in maintaining eye health. The eyes constantly produce basal tears, a thin film that lubricates the surface, preventing dryness and discomfort. This tear film also helps to wash away minor irritants and contains vital immune components.
Beyond basal tears, reflex tears are produced in larger quantities to flush out harmful substances like dust or fumes. These reflex tears contain antibodies that aid in fighting off bacteria, contributing to the eye’s natural protective barrier. This complex tear system ensures the eye remains moist, clean, and protected from various environmental threats and pathogens.
How Illnesses Trigger Watery Eyes
Illnesses can provoke watery eyes through several physiological mechanisms, often involving the body’s immune response and anatomical connections. When the body fights an infection, such as a common cold or flu, it initiates an inflammatory response. This systemic inflammation can extend to the delicate tissues around the eyes, causing irritation and stimulating increased tear production as a protective measure.
Nasal congestion, a hallmark of many illnesses, can significantly impact tear drainage. The nasolacrimal ducts, which drain tears from the eyes into the nasal cavity, can become blocked or narrowed due to swelling in the nasal passages. This obstruction leads to tears overflowing from the eyes, a condition known as epiphora. Viruses, like those causing the common cold, can directly irritate the eye’s surface, prompting reflex tearing to wash away the irritant.
Allergic reactions also commonly cause watery eyes. When exposed to allergens like pollen or pet dander, the immune system releases histamine. This chemical triggers an inflammatory cascade, leading to symptoms such as itching, redness, and tear production in the eyes. Histamine release can also affect tear film stability and cause swelling in the conjunctiva, contributing to watery eyes.
When Watery Eyes Signal More
While watery eyes are a symptom of a cold or allergies, they can sometimes indicate a more serious eye condition. For instance, conjunctivitis, often called pink eye, involves inflammation of the conjunctiva. This condition presents with red or pink eyes, a gritty sensation, and discharge.
The type of discharge can help differentiate causes: viral conjunctivitis produces a watery discharge, often accompanying a cold or respiratory infection. Bacterial conjunctivitis causes a thicker, pus-like discharge that can lead to eyelids sticking together, especially upon waking. Allergic conjunctivitis is marked by itching, tearing, and redness, often affecting both eyes simultaneously. Other conditions, such as a foreign body lodged in the eye or a corneal abrasion (a scratch on the clear outer surface of the eye), can also cause persistent watering, sharp pain, a feeling that something is in the eye, and light sensitivity.
Seeking Medical Advice
Most instances of watery eyes associated with illness resolve as the sickness subsides. However, certain symptoms warrant medical evaluation. Consult a healthcare professional if watery eyes are accompanied by persistent eye pain, significant changes in vision, or extreme sensitivity to light.
Other concerning signs include a thick, colored eye discharge (yellow, green, or white), eyelids that are stuck together, or severe redness that does not improve. If symptoms worsen over a few days or do not show improvement after a week, seeking medical attention is recommended. This helps determine if watery eyes are part of a general illness or point to a more localized eye issue.