Sir,

Ooi et al1 raised concerns regarding the safety profile of Ocublue Plus brand of Brilliant blue G dye (BBG, Aurolab, Madurai, India) as compared to Brilliant Peel (Geuder, Heidelberg, Germany) on the basis of their experimental study in a rodent model. The authors gave the impression that BBG was approved for use in the European Union (EU) only as Brilliant Peel, at 0.025% concentration. We herewith inform that Ocublue Plus at 0.05% concentration is also approved for use in EU, and is exported to 25 countries globally, including UK (V Kannan, Division Manager—Pharmacy, Aurolab, Madurai, India, personal communication). The authors stated that there was no preclinical/clinical study using Ocublue Plus. We and others have published several surgical studies using Ocublue Plus in peer-reviewed journals;2, 3, 4, 5, 6 all have reported excellent anatomical and visual outcomes. The authors next stated that studies using Brilliant Peel have shown it to be non-toxic. However, three of their five references to support this claim did not use Brilliant Peel; their first reference is our own study with Ocublue Plus!

The authors state in Discussion ‘the reduction in mean total neurosensory retinal thickness induced by Ocublue Plus was significantly greater than that of Brilliant Peel when compared with their controls.’ There are no data in their Results section to support this statement. They go on to conclude later that ‘Ocublue Plus caused thinning to the total neurosensory retina and reduction in the RGC density….’ Under Results, however, the total retinal thinning is reported to be similar to Ocublue Plus and Brilliant Peel (8 and −7 μm, respectively); the reduction in RGC density with the former was ‘equivocal’.

Some limitations such as the excessively long dye contact time (7 days) were discussed by the authors themselves. Their first figure highlights the limitations of statistical analysis using small numbers: the mean of retinal thickness difference is skewed by a single point data in each of the two BBG groups.1 While experimental studies on dye safety are essential and frequent, a study comparing two commercial brands of the same dye needs to be detailed and meticulous in its methodology, and cautious in its conclusions.