Abstract
Purpose :
Cicatrizing conjunctivitis (CC) is a significant cause of visual morbidity. It is important to differentiate progressive from non-progressive CC as the former often requires immunosuppressive therapy to avoid visual loss. Currently, progression of conjunctival scarring relies only on clinical assessment. More sensitive tools are needed to detect progression in conjunctival scarring. Using two-photon excitation and second harmonic generation (SHG), we studied the collagen structure in CC to find more sensitive and quantitative measures of scarring and evaluated their association with clinical severity.
Methods :
Conjunctival tissues obtained from patients with chronic CC as a result of Stevens-Johnson Syndrome were imaged. Relation to disease severity was correlated with our published validated CC clinical assessment tool comprising of inflammation, scarring, and morbidity scores. Collagen morphometry in regions of interest (ROI) was analyzed with FibroIndex software (HistoIndex, Singapore). Collagen fiber density (CFD) is the sum of the SHG pixel intensities within collagen area. Collagen area ratio (CAR) refers to relative amount of collagen compared to total area of ROI. Collagen fiber number (CFN) per square meter was defined as total number of collagen fibers per square meter in the ROI.
Results :
38 patients (13 with CC and 25 controls) were included. Compared to controls, diseased group had significantly smaller CAR (p<0.01), CFD (p=0.033) and CFN per square meter (p<0.01). In all groups, CAR was negatively correlated with inflammation score (R= -0.63, p <0.001), morbidity score (R= -0.52, p <0.001) and overall composite score (R = -0.32, p<0.05). In diseased groups alone, CAR was also negatively correlated with inflammation score (R = -0.55, p= 0.011). In diseased groups, CFN per square mm had significant correlation with all scores- inflammation (R = -0.49, p<0.01), morbidity (R= -0.37, p<0.01) and overall composite score (R = -0.33, p=0.02).
Conclusions :
We have further characterized the defining features of scar development in CC. With correlation to the clinical assessment tool, CAR was a reliable marker for diagnosis with negative correlation with scores in both groups. In diseased groups, CFN per square mm could be used to accurately predict the severity, being the only parameter having negative correlation with all scores.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.