What is the provisional diagnosis and management for a patient with left eye pain and redness for a week, who has been using contact lenses overnight, and presents with hand movement visual acuity, conjunctival redness, hypopyon, and central white corneal opacity?

Provisional Diagnosis: Bacterial Keratitis (Contact Lens-Related)

This patient has bacterial keratitis, most likely caused by Pseudomonas aeruginosa given the overnight contact lens wear, rapid progression over one week, severe vision loss to hand movement only, and presence of hypopyon with central corneal opacity. 1, 2

Clinical Reasoning

The constellation of findings is pathognomonic for severe bacterial keratitis:

• Unilateral presentation with severe pain and redness indicates infectious keratitis rather than bilateral allergic or viral conjunctivitis 3
• Hypopyon (layered white cells in anterior chamber) signifies severe intraocular inflammation from bacterial invasion 1
• Central white corneal opacity covering the pupil represents suppurative stromal infiltrate with surrounding edema and white cell infiltration 1
• Hand movement visual acuity reflects the central location of scarring, which causes substantial visual loss even if infection is eradicated 1

Predisposing Factors

Overnight contact lens wear is the single most important risk factor, increasing corneal infection risk 10- to 15-fold compared to daily wear. 1

Specific Risk Factors in This Case:

• Extended/overnight wear of contact lenses - accounts for 50-75% of microbial keratitis risk 1
• Compromised corneal epithelium from chronic lens wear, creating entry point for bacteria 1
• Pseudomonas aeruginosa is the most common organism in contact lens-related bacterial keratitis globally, causing rapid tissue destruction 1, 2, 4
• Likely poor lens hygiene - improper cleaning, water exposure, or failure to replace lens cases every 3 months 1

Common Pitfalls:

Do not assume this is simple conjunctivitis - the presence of hypopyon, central corneal opacity, and severe vision loss mandate immediate treatment for bacterial keratitis. 3

General Management

Immediate Actions (First Visit):

1. Remove and discard all contact lenses and cases immediately - they serve as reservoirs for reinfection 3, 5

2. Obtain corneal cultures before starting antibiotics: 1

• Corneal scraping for Gram stain, culture, and sensitivity
• Culture contact lenses and storage solution if available
• Document baseline visual acuity and photograph the lesion

3. Initiate intensive fortified topical antibiotic therapy immediately after cultures: 1

• Fortified cefazolin 50 mg/ml (covers Gram-positive organisms including Staphylococcus)
• Fortified tobramycin 14 mg/ml or gentamicin 14 mg/ml (covers Gram-negative organisms including Pseudomonas)
• Dosing: Every 30-60 minutes around the clock initially, then taper based on clinical response
• Refrigerate fortified antibiotics and shake well before instillation 1

Alternative monotherapy: Fluoroquinolone monotherapy (moxifloxacin 0.5% or levofloxacin 1.5%) may be used for less severe cases, but given this patient's severity with hypopyon, fortified antibiotics are preferred 2

Adjunctive Measures:

• Cycloplegic agents (cyclopentolate 1% or atropine 1%) to reduce pain and prevent posterior synechiae 1
• Avoid topical corticosteroids initially until infection is controlled and epithelial defect is healing 1
• Pain management with oral analgesics as needed 1

Follow-Up Protocol:

Daily examination initially to monitor: 1

• Size and depth of infiltrate
• Epithelial defect healing
• Anterior chamber reaction
• Intraocular pressure
• Visual acuity improvement

Modify antibiotics based on culture results and clinical response - if Pseudomonas confirmed, ensure coverage with antipseudomonal agent (tobramycin, gentamicin, or fluoroquinolone) 2

Red Flags Requiring Surgical Intervention:

• Progressive corneal thinning or perforation
• Lack of improvement after 48-72 hours of appropriate therapy
• Corneal abscess formation
• Endophthalmitis development 1

Critical Warnings:

Never resume contact lens wear until: 5

• Complete epithelial healing confirmed
• Absence of infiltrate
• Resolution of inflammation
• Minimum 7 days after completing antibiotic course

Counsel patient that: 1

• Overnight wear increases infection risk fivefold even with FDA-approved extended wear lenses
• Swimming, showering, or hot tub use with lenses dramatically increases Acanthamoeba risk
• Never rinse lenses or cases with any type of water (tap, bottled, or homemade saline)
• Replace lens cases every 3 months minimum under normal circumstances

Expected Outcomes:

With appropriate treatment, most bacterial keratitis cases respond to antibiotics within 48-72 hours. 1, 2 However, given this patient's severe presentation with central scarring and hand movement vision, permanent visual impairment is likely even with successful infection eradication. 1 Consider corneal transplantation for visual rehabilitation after infection resolution if significant scarring persists. 1