Abstract
Purpose: :
A new animal model based on Brown Leghorn hens has been used to assay the tolerance of mineral micronized pigments for cosmetic keratopigmentation.
Methods: :
Central or peripheral intrallamelar tattoos with either brown- or black-coloured iron oxide-based mineral micronized pigments were performed in 44 hens. A total of 8 eyes underwent surgery but received no pigment to serve as surgical control. One and three months after the surgery pigment diffusion, presence of inflammatory cells and neovascularization were determined by histopathological examination.
Results: :
Vision-impairing tattoos performed in the center of the cornea with black iron oxide presented only occasional cases of inflammation in comparison with brown iron oxide central tattoos where only 36.4% of the eyes show no signs of inflammation. No cases of neovascularization were found in central tattoos. Brown and black peripheral tattoos presented pigment diffusion, minimum levels of macrophages and new vessel formation. The number of cases increased at 3 months after surgery from 60% to 83.3% for black-coloured tattoos and from 60% to 100% for brown-coloured tattoos. Some cases of neovascularization were seen 1 month after surgery in eyes with brown tattoo but most of them appeared 3 months after surgery when 50% and 83.3% of the black and brown tattooed eyes presented new vessels.
Conclusions: :
Hens are an adequate animal model to study the tolerance of micronised pigments for keratopigmentation. Advantages of this model include their low price and easy maintenance and handling. The cosmetic final result as well as the adverse effects in keratopigmentation are determined by both composition and/or particle size of the pigment and the surgical technique.
Keywords: cornea: basic science • cornea: stroma and keratocytes • color pigments and opsins