Conjunctivitis, commonly known as pink eye, is a frequent condition involving the inflammation of the conjunctiva. The conjunctiva is the thin, transparent layer of tissue that covers the white part of the eye and the inner surface of the eyelids. When this membrane becomes inflamed, the small blood vessels within it swell, causing the eye to appear reddish or pink.
The Sensation of Conjunctivitis
Pink eye often feels like a scratch, a burning sensation, or the presence of a foreign body in the eye. This feeling is frequently described as having sand or grit stuck under the eyelid. The mechanism behind this sensation is the swelling of the inflamed conjunctiva. When the conjunctiva is irritated, its surface becomes slightly rougher and thicker. Every time a person blinks, the eyelid rubs over this swollen tissue, mimicking the feeling of scraping.
Distinguishing Other Symptoms
Redness, or hyperemia, across the white part of the eye is the most obvious sign. Discharge is another defining symptom, and its characteristics can hint at the underlying cause. Viral conjunctivitis typically produces a clear, thin, and watery discharge, though it can cause stickiness upon waking. In contrast, bacterial conjunctivitis often results in a thick, purulent discharge that is yellow or greenish in color. This thicker discharge frequently leads to the eyelids sticking together, especially after a long period of sleep.
Causes and Contagion Factors
Conjunctivitis is broadly categorized into three types, and the specific cause determines its duration and whether it is contagious. Viral conjunctivitis is the most common form, often caused by the same viruses responsible for the common cold, such as adenovirus. This type is highly contagious and spreads easily through contact with eye secretions or respiratory droplets. Bacterial conjunctivitis is less frequent and is caused by bacteria colonizing the eye’s surface. This form is also highly contagious. The third main type is allergic conjunctivitis, triggered by environmental allergens like pollen or pet dander. Allergic pink eye is not contagious and is primarily characterized by intense itching and watery discharge.
Knowing When to Seek Medical Help
While most cases of pink eye resolve on their own, certain “red flag” symptoms warrant immediate consultation with a healthcare professional. Any sudden change in vision, such as blurriness or a decrease in clarity, should be evaluated right away. Severe pain that seems disproportionate to the typical mild irritation is also a warning sign. Extreme sensitivity to light, known as photophobia, suggests a possible complication involving the cornea and requires prompt attention. If symptoms worsen significantly or do not begin to improve within 24 to 48 hours, medical intervention may be necessary.