Rose Bengal sodium, a synthetic fluorescein derivative, and is a crimson-coloured dye with the principal component being 4,5,6,7-tetrachloro-2,4,5,7-tetraiodo fluorescein. Rose Bengal sodium has been widely used as an ophthalmic diagnostic agents, and can detect desiccated or damaged cells on the ocular surface. Rose Bengal sodium exhibits antiviral activities[2].