"Black prosthesis" revisited: a study of epinephrine-induced pigment deposits on poly(methyl methacrylate)

Pigmented deposits on a Boston keratoprosthesis from topical ibopamine

PURPOSE

To report a case of pigmented deposits on a type I Boston keratoprosthesis (KPro) associated with the use of topical ibopamine as a treatment for hypotony.

METHODS

Case report and literature review.

RESULTS

The dopamine-like agent ibopamine caused black deposits on the bandage lens and on the front plate of the Boston KPro that resulted in reduced visual acuity. Change to a daily disposable contact lens and regular cleaning of the KPro front plate with diluted baby shampoo eliminated this problem.

CONCLUSION

This is the first report of this complication with topical ibopamine use and should be considered when ibopamine is used chronically for hypotony.

Melanized poly(HEMA) hydrogels: basic research and potential use

Synthetic melanogenesis, using epinephrine and other melanin precursors, within the matrix of hydrophilic polymers and copolymers of 2-hydroxyethyl methacrylate resulted in hydrogels able to absorb ultraviolet and visible radiation. This significantly enhances their value as materials for extraocular (contact lenses) or intraocular (artificial crystalline lenses) devices that should protect the retina of aphakic patients from potential damage induced by light. The two-phase morphology of melanized hydrogels, as investigated by TEM, revealed a fine structure that is possibly indicative of a true sequential interpenetrating polymer network. Their biocompatibility was evaluated by a set of different assays involving human choroidal fibroblasts. No cytotoxicity was found in the aqueous extracts of materials. By using an assay with cells and polymers embedded in a collagen gel, a short-range toxic effect was detected, presumably caused by melanin itself. However, in vivo experiments in animal eyes with melanized hydrogel intraocular lenses did not reveal any toxic reaction.