Quantitative Stain-Free Conjunctival Collagen Imaging in Cicatrizing Conjunctivitis Using Second Harmonic...

Area of Science:

• Ophthalmology
• Biomaterials Science
• Pathology

Background:

• Cicatrizing conjunctivitis (CC) causes significant morbidity, with current scarring assessment relying solely on clinical evaluation.
• Objective, quantitative measures are needed to assess CC progression and severity.
• Collagen structure alterations are implicated in conjunctival scarring.

Purpose of the Study:

• To investigate collagen structure in cicatrizing conjunctivitis (CC).
• To identify sensitive and quantitative measures for assessing CC scarring severity.
• To correlate collagen morphometry with clinical disease severity scores.

Main Methods:

• Conjunctival tissues from CC patients and controls were analyzed using two-photon excitation and second harmonic generation microscopy.
• Collagen morphometry, including collagen area ratio (CAR) and collagen fiber number (CFN)/mm², was quantified using FibroIndex software.
• Results were correlated with a validated clinical severity assessment tool.

Main Results:

• Diseased conjunctival tissue showed significantly lower CAR and CFN/mm² compared to controls.
• CAR positively correlated with inflammation, scarring, morbidity, and overall composite scores in CC patients.
• CFN/mm² negatively correlated with inflammation, scarring, morbidity, and overall composite scores across all groups.

Conclusions:

• Collagen area ratio (CAR) demonstrates significant correlation with clinical scores, suggesting its potential as a reliable diagnostic marker for CC.
• Collagen fiber number (CFN)/mm² exhibits significant negative correlation with all assessed scores, indicating its potential as a predictive marker for CC severity.