From the Guidelines
Adjunctive collagen cross-linking (PACK-CXL) is beneficial in the treatment of infectious keratitis, particularly bacterial keratitis, as it can accelerate healing and reduce treatment duration when used in conjunction with standard antimicrobial therapy. The use of PACK-CXL in the treatment of infectious keratitis has been supported by recent studies, including a randomized controlled study published in 2024 1, which found that patients who received a single cross-linking treatment in addition to standard medical therapy had faster re-epithelialization and shorter treatment duration than the control group receiving standard medical therapy alone.
Key Benefits of PACK-CXL
- Faster re-epithelialization
- Shorter treatment duration
- Potential to inhibit corneal melting, especially in bacterial keratitis
- Effective as an adjunctive therapy, particularly in cases refractory to medical therapy
The procedure involves the application of riboflavin drops to the cornea followed by controlled UV-A light exposure, which creates reactive oxygen species that strengthen corneal collagen fibers and kill pathogens. It is essential to note that PACK-CXL works best when performed early in the disease course and is particularly valuable for treatment-resistant infections or when antimicrobial susceptibility is unknown. However, it should be used cautiously in deep infections (>300 microns) and is contraindicated in herpetic keratitis, as it can worsen outcomes 1.
Considerations for PACK-CXL Use
- Should be used in conjunction with standard antimicrobial therapy
- Requires specialized equipment and training
- Can be performed as an outpatient procedure under topical anesthesia
- Patients should continue their prescribed antimicrobial medications after the procedure
- Cautious use in deep infections and contraindicated in herpetic keratitis
From the Research
Benefits of Adjunctive Collagen Cross-Linking (PACK-CXL) in Infectious Keratitis Outcomes
- The use of collagen cross-linking in the management of corneal infections, including infectious keratitis, has been explored as a potential treatment option 2.
- Photoactivated chromophore for collagen cross-linking (PACK-CXL) has been investigated as a treatment for infectious keratitis, with some studies suggesting its effectiveness in treating bacterial keratitis 3.
- The current evidence on the effectiveness of PACK-CXL for bacterial keratitis is of low certainty and clinically heterogenous in regard to outcomes 3.
Comparison to Antimicrobial Therapy Alone
- A review of three trials (two RCTs and one quasi-RCT) found that it is very uncertain whether PACK-CXL with standard antibiotic therapy is more effective than standard antibiotic therapy alone for re-epithelialization and complete healing 3.
- Another study found that riboflavin/ultraviolet-A (UVA) as an adjunct treatment for infectious keratitis appeared to be most effective when the infection depth was limited, and the success rate was higher for bacterial infections than fungal infections 4.
- Published data show that CXL is effective and safe as an adjunct to antibiotic treatment in selected cases of bacterial keratitis, but the benefit of CXL probably varies according to the etiology of the infection 5.
Safety and Efficacy
- The safety and efficacy of CXL in infectious keratitis have been discussed in several reviews, with some studies suggesting its potential as an adjunctive treatment option 2, 5, 6.
- However, the role of CXL in infectious keratitis remains unclear despite the reported success in some clinical cases, and further investigations are warranted concerning the efficacy and safety of treating infectious keratitis with CXL 6.