Data generated in an SHO mouse demonstrate that of ICG was reached 10 s after i.v. injection and the half-life of the SI was 1.2 min (Fig. 1 and Video 1). The received half-life result is in concordance with the published data.13,14 The reproducibility of this method was assessed by administering multiple injections of equal ICG dosages in short intervals in the same animal [Fig. 2(a) and Video 2]. The acquired average SI of the three repeated ICG applications revealed a nearly identical curve shape and only slight peak-level variations. The values are almost identical and were calculated to be 13 s (first application), 15 s (second application), and 15 s (third application), whereas the values for were 1.8, 2.2, and 2.5 min, respectively [Fig. 2(b)]. The continuously increasing half-life values may be attributed to the limited clearing capacity of the liver and the cumulative dose effect of the three applications leading to an accumulation of ICG in the blood. In a second study, we examined if the injection of escalating dosages of ICG correlated with increased fluorescence SIs in the eye [Fig. 3(a) and Video 3]. The maximum peak-levels of all three applications occurred after 3 s, however, the half-life was starting slightly to increase after the third ICG application (1.4, 1.3, and 1.6 min, respectively) [Fig. 3(b)], the latter indicating the same cumulative dose effect as mentioned before. The results of this experiment demonstrate a linear correlation between the administered compound concentration and their associated fluorescence SIs. Thus, different concentrations of a fluorescent compound can be distinguished by measuring the fluorescence intensity in the eye of a mouse.