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Disease&Treatment/Cornea&Ocular surfaces
Bacterial keratitis Contact lens-related infection, risk factors, causative organism, course and progression rate, severe prognosis, surgical indications
eye_doc 2025. 4. 21. 23:04
👁 “Bacterial Keratitis – A Sight-Threatening Ocular Emergency”
Bacterial keratitis is a sight-threatening corneal infection, particularly concerning in contact lens users or those with prior ocular trauma or surgery.
Modern antibiotics have reduced systemic infections, but corneal ulcers remain a major cause of irreversible vision loss.
🧠 Risk Factors for Bacterial Keratitis
CategoryRisk Details
Trauma | Corneal abrasion, foreign body, chemical insult |
Contact lenses | |
– All types involved | |
– Risk: Extended wear > Daily wear > RGP ≒ Disposable | |
– Silicone hydrogel does not reduce infection rate | |
Ocular surface disease | Dry eye, chronic inflammation, therapeutic lenses |
Refractive surgery | LASIK, RK → even years later |
Immunocompromised | AIDS: no higher incidence, but severe progression once infected |
🦠 Causative Organisms & Progression Speed
SpeedTypical Pathogens
Fast | Staph. aureus, Pseudomonas, Strep. pyogenes, Pneumococcus |
Slow | Nontuberculous Mycobacteria, Nocardia, Actinomyces, Moraxella |
⚠️ Clinical Red Flags for Severe Ulcer
IndicatorClinical Concern
Central corneal ulcer | Vision-threatening location |
Ulcer >6mm in size | Severe infiltration |
Deep stromal invasion | >1/3 thickness = high risk |
Imminent or actual perforation | Urgent surgery indicated |
Scleral extension | Sign of sclerokeratitis, requires aggressive treatment |
💉 Surgical Consideration Triggers
- Subconjunctival antibiotics
- Systemic antibiotics
- Therapeutic PKP (penetrating keratoplasty) for perforation or unresponsive cases