Comparison of the in vitro safety of intraocular dyes using two retinal cell lines: a focus on brilliant blue G and indocyanine green.

Purpose: To compare the in vitro toxicity of brilliant blue G (BBG), indocyanine green (ICG), Trypan blue (TB), and Evans blue (EB) in a human retinal pigment epithelial cell line (ARPE-19) and a murine retinal ganglion/Muller glial (RGC) primary cell culture.

Design: In vitro cell biology experimental study.

Methods: The dose-dependent toxicity of the dyes was determined by exposing each dye at four different concentrations to the two cell cultures for a short exposure (three minutes) and a medium exposure (30 minutes). The time-dependent toxicity of the dyes was also determined. All four dyes, each diluted to 1/500th of stock concentration, were applied only to the ARPE-19 cells for a prolonged exposure of two, 24, 48, and 72 hours. Cell viability was measured via a mitochondrial dehydrogenase assay.

Results: BBG was the only dye to cause toxicity in the ARPE-19 cell line at short exposure times. BBG and TB demonstrated toxicity at medium exposure times. BBG and ICG demonstrated toxicity at long exposure times and dilute concentrations. At short exposure times, none of the dyes caused toxicity in the RGC mixed primary cultures. In contrast, at medium exposure times, all dyes except ICG demonstrated toxicity that lessened with lower concentrations.

Conclusions: All dyes demonstrated relatively safe viability profiles in both cell lines at surgically relevant concentrations and times. Cell toxicity could be elicited at higher concentrations and longer exposure times. ICG had a favorable viability profile at almost all of the concentrations and times tested.