Pink eye — medically known as conjunctivitis — is an inflammation or infection of the conjunctiva, the thin transparent membrane that lines the inside of the eyelids and covers the white of the eye. It is one of the most common eye conditions seen in optometry, affecting people of all ages. While many cases resolve on their own, the appropriate treatment depends entirely on correctly identifying the underlying cause — and not all types are handled the same way.

Types of Conjunctivitis

  • Viral conjunctivitis — The most common form, typically associated with adenovirus (the same family that causes the common cold). Symptoms include watery discharge, redness, light sensitivity, and a gritty feeling. It is highly contagious and usually resolves on its own in 1–2 weeks. Antibiotics are not effective and should not be prescribed.
  • Bacterial conjunctivitis — Caused by bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, or Haemophilus influenzae. A key distinguishing feature is thick, purulent (yellow or green) discharge that often causes the lids to stick together in the morning. Antibiotic eye drops typically clear it within a week.
  • Allergic conjunctivitis — Triggered by airborne allergens (pollen, pet dander, dust mites). Both eyes are usually affected simultaneously, with intense itching as the hallmark symptom. Treatment includes antihistamine/mast cell stabilizer drops and addressing the underlying allergen exposure.
  • Chemical or irritant conjunctivitis — Caused by exposure to chlorine, smoke, contact lens solutions, or other irritants. Usually resolves quickly once the irritant is removed; copious flushing with water or saline is the first-line response.

When to See an Eye Doctor

While mild cases of viral or allergic conjunctivitis can be monitored at home, you should seek prompt professional evaluation if you experience:

  • Significant pain or light sensitivity
  • Vision changes or blurring
  • Symptoms lasting more than a week without improvement
  • Thick discharge suggesting bacterial infection
  • Contact lens wear — lens wear must be discontinued immediately and evaluated before resuming

Accurate diagnosis is critical, as misidentifying the type and prescribing unnecessary antibiotics contributes to antibiotic resistance. Contact us for a same-day or urgent evaluation — getting the right diagnosis quickly means faster, safer recovery.