Pus is a thick, opaque fluid that forms at sites of infection, representing a concentrated biological waste product of the body’s immune response. It is primarily composed of dead white blood cells (neutrophils), dead tissue, and a high concentration of live and dead bacteria. When pus contaminates the eye, the delicate ocular surfaces are immediately exposed to a massive bacterial load. Pus acts as a vector for infection, making its presence an urgent contamination event that requires immediate action to protect vision.
Immediate Eye Symptoms and Reactions
When pus enters the eye, the ocular surface reacts quickly to the foreign material and bacterial presence. The immediate response is often a foreign body sensation, described as grittiness or feeling like sand is trapped beneath the eyelid. This is accompanied by increased tear production as the eye attempts to dilute and flush the contaminant away. The conjunctiva, the clear membrane covering the white of the eye, typically becomes inflamed, resulting in visible redness (hyperemia). The pus can also cause a distinct burning or stinging sensation on the surface of the eye.
Potential Complications and Infection Risks
The inherent danger of pus is that it delivers a concentrated dose of bacteria directly onto the ocular surface. The most common risk is bacterial conjunctivitis (pink eye), where bacteria colonize the conjunctiva. Symptoms include persistent, thick, yellow or greenish discharge that quickly reappears, often causing the eyelids to stick together upon waking.
A more severe risk is bacterial keratitis, an infection of the cornea. Pathogens found in pus, such as Staphylococcus aureus or Pseudomonas aeruginosa, can rapidly invade the corneal tissue. Keratitis progresses quickly, causing inflammation, intense pain, and vision impairment. If not treated promptly, it can lead to a corneal ulcer (an open sore), which causes permanent scarring and threatens the clarity of the cornea, potentially leading to permanent vision loss. In rare instances, the infection can penetrate deeper, causing endophthalmitis, a painful internal infection requiring immediate medical intervention to prevent blindness.
Immediate Cleaning and First Aid
The goal of immediate first aid is to physically remove and dilute the bacterial load from the eye’s surface. First, thoroughly wash hands with soap and water to prevent introducing more pathogens. If contact lenses are worn, they must be removed immediately before flushing, as they can trap contaminants against the cornea.
The contaminated eye should be flushed continuously for several minutes using clean, lukewarm water or a sterile saline eyewash solution. To effectively flush the entire surface, hold the eyelids open and allow the fluid to run from the inner corner of the eye to the outer corner. Avoid rubbing the eye, as this can scratch the corneal surface and push bacteria deeper into the tissue. Never use homemade saline solutions or harsh chemicals for flushing, as they can cause further irritation or new infections.
When Professional Medical Care is Necessary
Even after thorough flushing, certain signs indicate a serious infection requiring professional medical evaluation. Seek prompt care if you experience persistent or worsening eye pain, or any change in visual acuity, such as blurred vision or the appearance of spots or floaters. Severe sensitivity to light (photophobia) requires an urgent visit to an eye care specialist, as it often accompanies serious conditions like keratitis. Medical treatment is necessary if thick, colored discharge continues to return frequently, or if redness and irritation do not improve within 24 hours of home care. These symptoms suggest an active bacterial infection that requires prescription antibiotic eye drops to prevent sight-threatening complications.