or would yield false-negative results (such as corneal fluorescein test).
Ocular surface staining with 1% fluorescein solution
The National Eye Institute (NEI)/Industry Workshop scale was used for evaluation of the amount of ocular surface staining with fluorescein (23).
During the study, the following tests were performed on our subjects: fluorescein staining test on both eyes, lissamine dye staining test on both eyes, TBUT test on both eyes, and Schirmer test on both eyes (Table 1).
The validity of fluorescein test was assessed by the Receiver Operating Characteristic (ROC) curve, where the sensitivity and specificity based on normal values are determined.