What is the pathophysiology of bacterial conjunctivitis (pink eye)?

Updated: Jan 03, 2019
  • Author: Karen K Yeung, OD, FAAO; Chief Editor: Andrew A Dahl, MD, FACS  more...
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The surface tissues of the eye and the ocular adnexa are colonized by normal flora such as streptococci, staphylococci, and corynebacteria. Alterations in the host defense, in the bacterial titer, or in the species of bacteria can lead to clinical infection. Alteration in the flora can also result from external contamination (eg, contact lens wear, swimming), the use of topical or systemic antibiotics, or spread from adjacent infectious sites (eg, rubbing of the eyes).

The primary defense against infection is the epithelial layer covering the conjunctiva. Disruption of this barrier can lead to infection. Secondary defenses include hematologic immune mechanisms carried by the conjunctival vasculature, tear film immunoglobulins, and lysozyme and the rinsing action of lacrimation and blinking.

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