Safety testing of blue vital dyes using cell culture models.

PURPOSE: To investigate the safety of trypan blue, brilliant blue G (BBG), Evans blue (EB), patent blue, Chicago blue (CB), and bromophenol blue (BB), with and without halogen and xenon light exposure. METHODS: All dyes were diluted in a balanced saline solution at a concentration of 0.5%. Cells of the human RPE line ARPE-19 and rat RGC5 were exposed to vital dyes for 5 min. Experiments with and without xenon or halogen illumination were performed. The viability of ARPE-19 and RGC5 cells was determined at 12, 24, or 120 h by a cell proliferation assay using WST-1 reagent. The apoptotic events as well as cell numbers were registered for 72 h and counted by time-lapse videomicroscopy. RESULTS: There was no evidence of ARPE-19 or RGC5 toxicity, immediate (0 and 24 h) or delayed (120 h), following exclusive exposure to each single dye. After halogen light exposure, ARPE-19 cell lines did not show any significant toxicity, except for when they were exposed to EB. After xenon illumination, ARPE-19 cells showed a marked decrease in cell viability when exposed to EB or CB and a moderate decrease when exposed to BBG and BB. After xenon illumination, RGC5 cells showed the highest decrease in cell viability when exposed to EB and CB; BB caused the same decrease in cell viability as in ARPE-19 cells. CONCLUSION: Interaction of light from endo-illumination source and blue vital dyes may increase the risk of retinal toxicity.

Vital dyes for macular surgery: a comparative electron microscopy study of the internal limiting membrane.

PURPOSE: To analyze and compare the ultrastructure of the retinal cleavage plane of the internal limiting membrane (ILM) removed during dye-assisted macular surgery. METHODS: Ninety-six surgical specimens of the ILM obtained during trypan blue (TB)-, brilliant blue G (BBG)-, bromphenol blue (BPB)-, Chicago blue (CB)-, and indocyanine green-assisted pars plana vitrectomy for idiopathic macular hole and macular pucker were evaluated using transmission electron microscopy. Specimens removed without dye assistance served as controls. RESULTS: Specimens removed after TB-, BBG-, BPB-, and CB-staining presented with significantly less cellular fragments (in size and quantity) at the retinal side of the ILM than specimens after indocyanine green staining. Large cellular fragments and Müller cell endfeet, which were typically present after indocyanine green staining, were not found after TB, BBG, BPB, and CB staining. Comparing all groups, TB was found with less retinal debris than BBG, BPB, and CB. Specimens removed without intravitreal dye administration showed the least retinal fragments that were solitarily distributed at the ILM. CONCLUSION: Trypan blue, BBG, BPB, and CB cause significantly less morphologic changes at the retinal cleavage plane than indocyanine green. Further studies are required to elucidate if presence and amount of retinal cell fragments at ILM specimens correlate with functional deficits.

Vital dyes for chromovitrectomy.

PURPOSE OF REVIEW: The aim of this article is to present the current state-of-the-art in regard to the application of vital dyes during vitreoretinal surgery, 'chromovitrectomy', as well as to overview the current literature regarding the properties of dyes, techniques of application, indications, and complications in chromovitrectomy. RECENT FINDINGS: A large body of published research has recently addressed the toxicity profile of indocyanine green for chromovitrectomy. Experimental data demonstrate dose-dependent toxicity of indocyanine green to various retinal cells. Newer generation vital dyes for chromovitrectomy include trypan blue, patent blue, triamcinolone acetonide, infracyanine green, sodium fluorescein, bromophenol blue, fluorometholone acetate and brilliant blue. Novel instruments may enable a selective painting of preretinal tissues during chromovitrectomy. SUMMARY: This review suggests that the field of chromovitrectomy represents an expanding area of research. The first line agents for internal limiting membrane staining in chromovitrectomy are indocyanine green, infracyanine green, and brilliant blue. Patent blue, bromophenol blue and trypan blue arose as outstanding biostains for visualization of epiretinal membranes. Novel dyes available for chromovitrectomy deserve further investigation.