An in vivo evaluation of Brilliant Blue G in animals and humans

Background/Aims: To evaluate the retinal toxicity of Brilliant Blue
G (BBG) following intravitreal injection in rat eyes and examine
the biocompatibility and the staining properties in humans.Methods:
BBG was injected into the 11 rat eyes to evaluate toxic effects
with balanced salt solution (BSS) serving as control. Retinal
toxicity was assessed by retinal ganglion cell (RGC) counts and by
light microscopy 7 days later. In addition, BBG was applied during
vitrectomy for macular hole (MH) (n = 15) or epiretinal membranes
(ERM) (n = 3) in a prospective, non-comparative consecutive series
of patients. Before and after surgery, all patients underwent a
complete clinical examination including measurement of best
corrected visual acuity (VA) and intraocular pressure, perimetry,
fundus photography and optical coherence tomography. Patients were
seen 1 day before surgery and then in approximately four weeks
intervals.Results: No significant reduction in RGC numbers and no
morphological alterations were noted. A sufficient staining of the
internal limiting membrane (ILM) was seen in patients with MH,
while the staining pattern in ERM cases was patchy, indicating that
parts of the ILM were peeled off along with the ERM in a variable
extent. All MHs could be closed successfully. VA improved in 10
eyes (56%; 8/15 MH patients, 2/3 ERM patients), was unchanged in
four eyes (22%; all MH patients) and was reduced in four eyes (22%;
3/15 MH, 1/3 ERM). No toxic effects attributable to the dye were
noted during patient follow-up. The ultrastructure of tissue
harvested during surgery was unremarkable.Conclusion: Brilliant
Blue provides a sufficient and selective staining of the ILM. No
retinal toxicity or adverse effects related to the dye were
observed in animal and human studies. The long-term safety of this
novel dye will have to be evaluated in larger patient series and a
longer follow-up.