Título / Title

COMBINED BRILLIANT AND TRYPAN BLUE: BEHAVIOR IN BSS, PH AND OSMOLARITY

Introdução / Purpose

Brilliant blue (BB) and trypan blue (TB) are dyes commonly used in chromovitrectomy. Density of BB is lower than that of balanced salt solution (BSS), so it tends to diffuse instead of depositing over epiretinal membrane (ERM) or internal limiting membrane (ILM). Furthermore, TB by itself can be toxic to retinal pigment epithelial cells at high concentration or prolonged exposition. To resolve these problems, association with glucose or polyethylene glycol (PEG) can be performed. However, glucose may increase risk of osmolar toxicity, and PEG is not always available.

Material e Método / Methods

Brilliant Blue 0.05% and its combination with TB 0.1%, in a proportion 1:1 (Brilliant Trypan - BT), were compared. Four 5 ml syringes with 27-gauge needles, containing approximately 1 ml of each solution were used. Initially, the syringes were submerged in 2 ml of BSS, and gravitational passive diffusion was observed. Afterwards, another syringes were lifted 0.5 mm over 2 ml of BSS, and behavior of drops was registered. Analysis of pH, osmolarity and density was performed. Finally, both solutions were utilized to visualize ERM/ILM during vitrectomy, and BT was used to dye anterior capsule during phacoemulsification surgery.

Resultados / Results

In both tests, BB 0.05% floated in BSS while BT instantly sank. This behavior can be explained by density, which is approximately 1,000.26 mg/ml for BB, 1,025.97 mg/ml for BSS and 1,126.05 mg/ml for BT. Moreover, it presented pH of 7.09 and osmolarity 304.5 mOsm, so within safety range found in medical literature (about 7 and 290, respectively). During vitrectomy, BB diffused though BSS, while BT fallen down, producing a "waterfall effect", similar to PEG solutions.

Discussão e Conclusões / Conclusion

BT has higher density than BB 0.05%, reaching posterior pole in a shorter time, presenting pH and osmolarity within a safety range. Additionally, it and can be used as a single dye injection to stain anterior capsule, ERM and ILM, with no additional toxicity.

Palavras Chave

chromovitrectomy; brilliant blue; trypan blue