AIM: To analyze the stability of different concentrations of fluorescein sodium solution on the detection of tear break-up time(TBUT).

METHODS:A retrospective study. A total of 150 cases(150 eyes)who came to our dry eye clinic with good cooperation from August 2019 to September 2021 were selected for the study, and the subjects were randomly divided into five groups, which were fluorescein sodium(FLS, 0.5%), FLS(1.0%), FLS(1.5%), FLS(2.0%)and fluorescein sodium parallel(FLSP), with 30 patients in each group(all the right eyes were the subject eyes). Each group was dripped with the corresponding fluorescein sodium. The FLSP group was the fluorescent test strip detection group. The slit lamp image scores of different concentration groups were compared, the survival time of sodium fluorescein at the instant, 2, 5, 10, 15 and 30min points was observed in each group, and the mean value of TBUT in each group was recorded.

RESULTS: The image score of FLS(0.5%)group was significantly higher than that of the other four groups(t=7.746, 21.483, 116.190, 38.730, all P<0.01). The image score of FLS(1.0%)group was significantly higher than that of FLS(1.5%)and FLS(2.0%)group(t=10.742, 15.492, all P<0.01). The survival time of fluorescein in FLS(0.5%)group was significantly shorter than that of the other four groups(t=8.226, 7.458, 9.159, 12.347, all P<0.01). The survival time of fluorescein in FLS(1.5%)group was significantly longer than that of FLS(1.0%)and FLS(2.0%)group(t=15.428, 13.274, all P<0.05). TBUT in FLS(0.5%)group was significantly higher than that of the other four groups at 2min(t=22.767, 22.345, 15.494, 17.213, all P<0.01), and was significantly lower than that of the other four groups at 10min(t=23.266, 25.353, 10.183, 22.025, all P<0.01). The mean first TBUT of FLS(1.5%)group was significantly shorter than that of the other four groups(t=25.236, 21.374, 19.658, 72.341, all P<0.01), and the mean first TBUT of FLSP group was significantly longer than that of the other four groups(t=22.487, 30.267, 60.247, 40.857, all P<0.01). There was no significant correlation between TBUT and ocular surface disease index(OSDI)and tear river height(r_s=-0.072, 0.219, P=0.689, 0.112). TBUT was positively correlated with tear secretion(r_s=0.674, P<0.01).

CONCLUSION: FLS(0.5%)had higher image quality but it was only suitable for observing staining within 5min, and the FLSP group was more suitable for clinical observation of corneal fluorescence staining for a longer period; FLS(1.5%)was the most stable and reliable concentration and dose for the detection of TBUT.