Evaluating Corneal Fluorescein Staining Using a Novel Automated Method

Purpose: To evaluate interobserver concordance in measured corneal fluorescein staining (CFS) using the National Eye Institute/Industry (NEI) grading scale and the Corneal Fluorescein Staining Index (CFSi), a computer-assisted, objective, centesimal scoring system. Methods: We conducted a study to evaluate CFS in clinical photographs of patients with corneal epitheliopathy. One group of clinicians graded CFS in the images using the NEI while a second group applied the CFSi. We evaluated the level of interobserver agreement and differences among CFS scores with each method, level of correlation between the two methods, and distribution of cases based on the CFS severity assigned by each method. Results: The level of interobserver agreement was 0.65 (P < 0.001) with the NEI, and 0.99 (P < 0.001) with the CFSi. There were statistically significant differences among clinicians' measurements obtained with the NEI (P < 0.001), but not with the CFSi (P = 0.78). There was a statistically significant correlation between the CFS scores obtained with the two methods (R = 0.72; P < 0.001). The NEI scale allocated the majority of cases (65%) within the higher quartile in the scale's severity (12-15/15). In contrast, the CFSi allocated the majority of cases (61%) within the lower quartile in the scale's severity (0-25/100). Conclusions: The CFSi is easy to implement, provides higher interobserver consistency, and due to its continuous score can discriminate smaller differences in CFS. Reproducibility of the computer-based system is higher and, interestingly, the system allocates cases of epitheliopathy in different severity categories than clinicians do. The CFSi can be an alternative for objective CFS evaluation in the clinic and in clinical trials.