What is the recommended management for corneal ulcers?

Management of Corneal Ulcers

The recommended management for corneal ulcers includes obtaining corneal scrapings for culture, initiating intensive topical antibiotic therapy, and considering adjunctive treatments such as corticosteroids after initial improvement, with close monitoring throughout the treatment course. 1

Diagnosis and Initial Assessment

• Corneal scrapings should be obtained using a topical anesthetic (preferably proparacaine 0.5%, avoiding tetracaine due to its antimicrobial effect) and a sterile instrument such as a blade or spatula to collect material from the base or periphery of the suspected infection 1
• Samples should be inoculated directly onto appropriate culture media or placed in transport media and promptly taken to the laboratory 1
• A simplified collection device using a nylon-tipped flocked swab has shown similar culture positivity rates compared to traditional methods 1
• For deep stromal infections or poor response to treatment, corneal biopsy may be indicated 1

Initial Treatment

• Topical antibiotic eye drops are the preferred method of treatment for bacterial keratitis, capable of achieving high tissue levels 1
• For central or severe keratitis (deep stromal involvement or infiltrate larger than 2 mm with extensive suppuration), a loading dose every 5-15 minutes followed by hourly applications is recommended 1
• Single-drug therapy using a fluoroquinolone has been shown to be as effective as combination therapy with fortified antibiotics 1
• Fortified topical antibiotics should be considered for large and/or visually significant corneal infiltrates, especially if a hypopyon is present 1
• Ciprofloxacin 0.3%, ofloxacin 0.3%, and levofloxacin 1.5% have FDA approval for treating bacterial keratitis 1
• For fungal keratitis, natamycin 5% is recommended with initial dosing of one drop hourly or every two hours, which can be reduced to 6-8 times daily after 3-4 days, continuing for 14-21 days 2

Monitoring and Follow-up

• Patients should be followed daily initially until clinical improvement is confirmed 1
• If cultures are negative and clinical response is poor, consider stopping antibiotic treatment for 12-24 hours and then reculturing 1
• For fungal keratitis, failure of improvement after 7-10 days of natamycin suggests the infection may be caused by a resistant microorganism 2

Adjunctive Therapy

• Cycloplegic agents may be used to decrease synechiae formation and pain from anterior segment inflammation 1
• Topical corticosteroid therapy may be considered after at least 2-3 days of progressive improvement with antibiotics, typically after pathogen identification and ruling out fungal infection 1
• Corticosteroids should be used with caution, with the minimum amount required to control inflammation 1
• Subgroup analysis of the SCUT trial showed potential benefit for corticosteroids in Pseudomonas keratitis and severe cases, but poor outcomes with Nocardia keratitis 1
• Adding topical corticosteroids within 2-3 days of antibiotic therapy resulted in better visual acuity at 3 months compared to later addition 1
• IOP must be monitored, and patients should be examined within 1-2 days after initiating corticosteroid therapy 1

Special Considerations

• Patients with pre-existing corticosteroid therapy should have their regimen reduced or eliminated until the infection is controlled 1
• Chronic topical immunotherapy increases the risk of infectious crystalline keratopathy, which may require discontinuation of immunotherapy and long-term antimicrobial treatment 1
• For contact lens wearers with corneal abrasions, patching the eye or using therapeutic contact lenses is not advised due to increased risk of secondary bacterial keratitis 1

Prevention

• Patients with risk factors for bacterial keratitis should be educated about their increased risk and the signs and symptoms that warrant prompt ophthalmological consultation 1
• Ocular surface diseases such as epithelial defects, tear deficiency, entropion, or lagophthalmos should be treated 1
• Prophylactic antibiotics should be prescribed for contact lens wearers with corneal abrasions and for patients with trauma-related abrasions 1

Common Pitfalls

• Delaying appropriate culture and sensitivity testing can lead to ineffective treatment 1
• Using tetracaine as an anesthetic for corneal scraping can interfere with culture results due to its antimicrobial effect 1
• Inappropriate use of corticosteroids, particularly in cases of Nocardia or fungal keratitis, can lead to poor outcomes 1
• Failure to recognize and address underlying risk factors can lead to recurrent infections 1
• Overuse of prophylactic antibiotics may promote growth of resistant organisms 1