Corneal drug delivery with tattoo technique: A new route for intrastromal cornea administration

Purpose: The purpose of this study was to describe a new corneal drug delivery technique using a tattoo machine. Materials and Methods: Five human eye bank corneas and four rabbits were included in the study. All interventions were performed with a tattoo machine with the following: 60-Hz needling speed, 200-μ needling depth, and liner cartridges with seven solid microneedles. Our study was conducted in two stages: an experimental model with ink injection in eye bank corneas and a drug delivery in the corneas of live rabbis. Each cornea received from the eye bank was injected with black and brown inks. Each rabbit received an intrastromal application of biguanide 0.2 mg/mL, triamcinolone 40 mg/mL, or bevacizumab 25 mg/mL. Dry needling was performed in the fourth rabbit. The rabbits were followed clinically for 30 days and were euthanized on day 30. All corneas were photographed before and after the procedure and then processed, stained with H and E, and underwent microscope analysis. Results: In the human corneas, pigment was delivered into the corneas with the tattoo machine and the ink remained in the stroma at the desired and stipulated depth. In the rabbits, the treated corneas showed no vascularization, inflammatory cells, or corneal perforation after 30 days of the procedure. Conclusions: Corneal drug delivery performed with the tattoo machine was achieved without side effects. Further studies are needed to determine the safety and effectiveness of the intervention in ocular pathologies.