The human eye—a marvel of biological engineering—is also remarkably vulnerable to a wide array of infections. From the common “pink eye” that spreads rapidly among schoolchildren to sight-threatening corneal ulcers and orbital cellulitis, eye infections can range in severity from mild discomfort to true medical emergencies. Early recognition, proper diagnosis, and prompt treatment are essential not only to relieve pain and inflammation but also to preserve your vision. This guide provides an in-depth look at the most prevalent eye infections, explores their causes and clinical presentations, and reviews current best practices for treatment and prevention.
1. Anatomy of the Eye and Routes of Infection
To understand how infections take hold, it helps to recall basic eye anatomy:
- Conjunctiva: The thin, transparent membrane lining the eyelids and covering the white of the eye.
- Cornea: The clear, dome-shaped front surface of the eye that focuses light.
- Eyelids and Eyelashes: Provide protection; contain oil glands (meibomian glands) that maintain tear-film stability.
- Orbital Tissues: Fat, muscle, and connective tissue that support the eyeball within the bony orbit.
Microbes may invade the eye via:
- Direct Contact—Touching or rubbing your eyes with contaminated hands.
- Droplet Spread—Respiratory viruses landing on the conjunctiva (e.g., adenovirus).
- Contact Lenses—Improper cleaning fosters bacterial or amoebic growth on lens surfaces.
- Trauma—Scratches or foreign bodies introduce pathogens directly to deeper tissues.
- Hematogenous Spread—Bloodborne bacteria or fungi seed the internal eye in immunocompromised patients.
2. Bacterial Conjunctivitis (“Pink Eye”)
2.1 Overview
Bacterial conjunctivitis is among the most common eye infections, especially in children. Typical culprits include Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae.
