Quantifying ocular surface inflammation and correlating it with inflammatory cell infiltration in vivo: A novel method

PURPOSE. The purpose of this study was to develop a novel, objective, and semiautomated method to quantify conjunctival redness by correlating measured redness with standard clinical redness and symptom scales and inflammatory cell infiltration. METHODS. Eleven outpatients presenting with mild to severe conjunctival hyperemia were included in the study. Clinical examination included patient history; visual analogue score (VAS) for ocular symptoms; 25-item National Eye Institute Visual Function Questionnaire (NEIVFQ 25) for quality of life/vision; photographs of the anterior segment graded for conjunctival hyperemia, using Efron, relative redness of image (RRI), and edge feature (EF) scales; and conjunctival impression cytology analyzed by flow cytometry. Differences between affected and unaffected eyes were evaluated, and correlations among questionnaire scores, ocular hyperemia grading scores, and assessment of biological markers were performed. RESULTS. Visual analogue score (P < 0.0001), Efron scale (P = 0.0003), RRI scores (P = 0.0004), and EF scores (P < 0.0001) and the percentage of granulocytes (defined as cluster of differentiation [CD] 45^dim; P = 0.0080) were significantly higher in affected eyes. Conversely, the percentage of CD45^bright leukocytes was reduced in affected eyes (P = 0.0054). Both the RRIs and EFs were positively correlated with VAS, Efron scale, percentages of conjunctival granulocytes, and CD45b^brightCD3^neg cells, whereas they were negatively correlated with the percentage of CD45^bright CD3^pos cells. Edge feature and RRI were correlated (Spearman r = 0.78, P < 0.0001). CONCLUSIONS. Ocular redness is a cardinal sign driving clinical judgment in highly prevalent ocular disorders; hence, we suggest that our semiautomated and reproducible method may represent a helpful tool in the follow-up of these patients.