Corneal cross-linking guards against infectious keratitis: an experimental model

Area of Science:

• Ophthalmology
• Microbiology
• Biomaterials Science

Background:

• Photo-activated chromophore for keratitis-corneal cross-linking (PACK-CXL) offers a novel approach for treating corneal infections.
• PACK-CXL enhances stromal resistance to inhibit corneal melting and possesses microbicidal properties via photo-activated riboflavin.

Purpose of the Study:

• To evaluate the efficacy of PACK-CXL in managing experimental bacterial keratitis in a rabbit model.
• To assess the impact of PACK-CXL on corneal inflammation, ulceration, and stromal integrity.

Main Methods:

• Bacterial keratitis (Pseudomonas aeruginosa and Staph aureus) was induced in rabbit corneas.
• Half of the eyes underwent corneal cross-linking 6 weeks prior; the other half served as controls.
• Clinical and histopathological examinations assessed inflammation, ulceration, organism penetration, and stromal affection depth.

Main Results:

• Cross-linked eyes exhibited significantly less severe inflammation compared to control eyes.
• No corneal melting was observed in the PACK-CXL treated group, versus 6 eyes in the control group.
• Histopathology revealed superficial inflammation confined to the stroma in PACK-CXL eyes, contrasting with deep infiltration in control eyes.

Conclusions:

• PACK-CXL effectively localizes infections by increasing corneal rigidity and resistance to enzymatic degradation.
• The protective effect of PACK-CXL on corneal integrity is evident even without the riboflavin microbicidal action.
• Early consideration of PACK-CXL in infectious keratitis treatment algorithms is recommended.