Corneal Ulcers & Microbial Keratitis
A sight-threatening defect in the corneal epithelium with underlying stromal infiltration caused by bacterial, fungal, viral, or amoebic infection.
Article Table of Contents
1. Comprehensive Overview
Microbial Keratitis / Corneal Ulcer is an acute, sight-threatening ophthalmologic emergency characterized by epithelial loss and active stromal inflammatory necrosis.
Pathogenic Subtypes: 1. Bacterial Keratitis: Prevalent among contact lens wearers (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus). Pseudomonas can cause enzymatic liquefactive stromal necrosis and perforation within 24–48 hours. 2. Viral (Herpetic) Keratitis: Herpes Simplex Virus (HSV-1) reactivation presenting as characteristic epithelial branching dendritic ulcers with terminal end-bulbs and corneal hypoesthesia. 3. Fungal Keratitis (Fusarium, Aspergillus, Candida): Associated with vegetative ocular trauma (tree branches, soil) or chronic immunosuppressive steroid drops. Presents with feathery stromal infiltrates and satellite lesions. 4. Acanthamoeba Keratitis: A devastating protozoan infection almost exclusively seen in contact lens wearers who rinse lenses in tap water or swim/shower with lenses; characterized by agonizing pain out of proportion to early slit-lamp findings and radial perineural infiltrates.
2. Symptoms & Warning Signs
If you observe any of the following symptoms repeatedly, an eye exam is strongly recommended:
- Excruciating, sharp ocular pain and intense foreign-body sensation
- Severe ciliary injection and 360-degree deep perilimbal redness
- Visible focal white or grayish stromal infiltrate/opacity on the clear cornea
- Abrupt, severe decline in visual acuity
- Severe photophobia and involuntary eyelid spasm (blepharospasm)
- Copious purulent discharge and excessive tearing
- Hypopyon (layering of white blood cells/pus in the anterior chamber) in advanced cases
3. Causes & Risk Factors
- 1Contact lens misuse (overnight wear, inadequate disinfection, tap water exposure, extended wear)
- 2Traumatic corneal abrasions from foreign bodies, fingernails, or organic vegetative matter
- 3Severe neurotrophic keratopathy or exposure keratopathy from facial nerve palsy
- 4Reactivation of latent Herpes Simplex Virus (HSV) in the trigeminal ganglion
- 5Unsupervised use of topical corticosteroid drops suppressing local corneal immune defenses
4. Treatments & Medical Management
5. Prevention & Daily Eye Care Advice
- Strict contact lens hygiene: never sleep in lenses, never expose to water, and replace cases monthly
- Wearing protective safety goggles during metalwork, gardening, and construction
- Immediate medical treatment of any minor corneal abrasion before microbial superinfection occurs
- Never self-medicating red eyes with over-the-counter steroid formulations
6. When to Seek Emergency Eye Care
Visit an immediate eye emergency center if you experience any of the following critical indicators:
- ⚠Appearance of any white spot or haze on the clear cornea accompanied by pain
- ⚠Any pain, redness, or discharge in a contact lens wearer (remove lens and seek urgent care)
- ⚠Sudden loss of visual clarity or inability to tolerate light
- ⚠Visible pus layering inside the anterior chamber
7. Frequently Asked Questions
Q:What should a contact lens wearer do if sudden pain and redness develop?
Immediately remove contact lenses, preserve them and their case for potential culture, and proceed directly to an ophthalmologist. Do not self-treat with random drops, as bacterial ulcers can perforate within 24 hours.