Abstract
Abstract: :
Purpose: Indocyanine green dye (ICG) dye is used in macular hole surgery to assist in visualization of the internal limiting membrane (ILM). Several authors have suggested that its use has contributed to worse visual outcomes and increased retinal pigment epithelial (RPE) aberrations. Trypan blue (TB) dye has been used safely and effectively to visualize the anterior lens capsule during cataract surgery and is being used by some surgeons to stain the ILM. We compared the toxicity of both dyes to human RPE cell cultures. Methods: ICG dye (IC-Green; Akorn Inc) and TB (MembraneBlue, Dutch Ophthalmic Research Corporation) were applied to ARPE-19 (ATCC) and primary human RPE cell cultures at various concentrations and over varying periods. Fiberoptic light was applied to some tissue wells. All cultures were subjected to a mitochondrial dehydrogenase assay (MTT, Sigma-Aldrich Fine Chemicals, USA) according to the manufacturer's protocol. Results: TB was not toxic to the RPE cell cultures at any concentration or over any period of exposure. ICG dye demonstrated dose-dependant and exposure-dependant toxicity. ICG dye was found to be toxic to the cells at the supplied concentration of 5.0mg/ml (26.1% cell survival) down to a concentration of 0.5mg/ml (92.8% cell survival) over a 3-minute exposure. ICG was significantly more toxic than TB at all periods of exposure to the aforementioned concentration range (p<0.001). Addition of light to the cultures increased cell death by the same proportion in controls and dye-treated cells: no increase in phototoxicity was demonstrated with the addition of either dye. Long periods of exposure, 2hrs, 24hrs and 48hrs, to minute concentrations of either dye did not produce cell death. At 60 seconds of exposure, ICG 0.5mg/ml was not toxic to the cell cultures. Conclusions: ICG demonstrates more toxicity than trypan blue to human RPE cell cultures. A clinically useful concentration of 0.5mg/ml ICG for 60 seconds does not cause significant cytotoxicity.
Keywords: retinal pigment epithelium • drug toxicity/drug effects • macular holes