The effects of the intraocular dye brilliant blue G (BBG) mixed with varying concentrations of glucose on retinal function in an isolated perfused vertebrate retina.

BACKGROUND: During vitreoretinal surgery, vital dyes such as brilliant blue G (BBG) are used to visualize anatomical structures. By adding glucose to a concentration of 5%, many surgeons try to achieve a dye mixture heavier than water to facilitate staining of the ILM without preceding fluid-air exchange. However, the intraocular use of high glucose concentrations is critical. This study investigated the effect of 0.4 ml BBG (Brilliant Peel™ 0.25 mg/ml, Fluoron, Ulm, Germany) mixed with various glucose concentrations on the retina in an pseudo in vivo model
METHODS: Bovine retinas were isolated and superfused with an oxygen saturated nutrient solution, and the electroretinogram (ERG) was recorded. BBG mixed with 0.05 ml/0.1 ml/0.15 ml glucose 40% was applied epiretinally. ERG recovery was monitored for 75 minutes. 1 mM aspartate was added to the nutrient solution to obtain a-waves.
RESULTS: After application of BBG/0.05 ml 40% glucose, a non-significant decrease of the b-wave amplitude was recorded (11.2%). In contrast, higher glucose concentrations showed a significant decrease of the b-wave (23.40% at 0.1 ml glucose, 26% at 0.15 ml glucose). The a-wave amplitudes showed no significant change at the end of the washout for all concentrations.
CONCLUSIONS: The clinically used mixture of BBG and glucose seems to be safe up to a concentration of 5%. However, higher concentrations of glucose starting from 10% showed strong evidence of a toxic effect on the retinal function and should be avoided.