Comparison of in vitro toxicity of single vs double exposures of indocyanine green in human retinal pigment epithelial cell cultures.

Purpose: To compare the in vitro effect of a single brief indocyanine green (ICG) exposure with a double exposure on retinal pigment epithelial (RPE) cells.

Design: In vitro laboratory experimental study.

Methods: Human ARPE-19 cells were exposed to a single dilute ICG exposure (0.5 mg/ml) or to two sequential exposures of identical volume and concentration. Viability was measured with a mitochondrial dehydrogenase assay and compared with nonexposed control cells.

Results: Cell viability was not statistically different between the single-exposed, double-exposed, or control cell populations.

Conclusions: When used intraoperatively to stain the internal limiting membrane, dilute ICG dye sometimes does not adequately enhance visualization of the internal limiting membrane. Occasionally, it is necessary to repeat the dye exposure to achieve the desired visibility. In this study, RPE cells subjected to two consecutive short exposures of ICG showed no marked difference in cell survival when compared with cells exposed to a single application of ICG and to control cells.