Purpose: To examine the intracellular uptake and extracellular binding of indocyanine green (ICG) and trypan blue (TB) by human retinal pigment epithelium (RPE) cells in vitro at clinically relevant concentrations.
Methods: Human RPE cells (ARPE19 cells) were exposed to 0.01%, 0.05%, and 0.25% ICG or 0.06%, 0.15%, and 0.25% TB for 15 seconds, 30 seconds, and 5 minutes, and the dye concentrations taken up by the cells were evaluated by spectrophotometric analysis.
Results: ICG was significantly taken up by ARPE19 cells after exposure to 0.05% for 5 minutes, 0.01% for 30 seconds, and 0.25% ICG for 15 seconds, whereas TB was not taken up by RPE cells under the conditions in this study.
Conclusion: ICG is bound and taken up by RPE cells at concentrations lower than clinically used, and TB is not. Understanding the effects of dyes on ocular tissues leads to more effective and safer dye-assisted vitrectomy protocols, although the experimental setting is different from the clinical situation.