A colouring intended to be used to stain tissues/structures in the eye during ophthalmic surgery (e.g., phacoemulsification vitrectomy) to enhance the visibility of specific tissues/structures (e.g., anterior lens capsule, vitreous body) to facilitate the procedure, or used to stain a corneal graft before keratoplasty. It is typically available as a solution (e.g., trypan blue, triamcinolone). After application, this device cannot be reused.