Retinal tacks: tolerance and tissue reaction in a human eye.

We report the histopathologic findings in a human eye enucleated after insertion of three nonmagnetic, metallic alloy tacks for treatment of a giant retinal detachment. Five months after surgery one of the tacks was detected in the anterior chamber. Two tacks remained in situ and induced a localized glial reaction, breaks in Bruch's membrane, disappearance of the retinal pigment epithelium and choriocapillaris immediately around the tack, and a variable extent of chorioretinal adhesion. The penetration of the tacks in the choroid and sclera was associated with a localized scar and only a mild inflammatory reaction, but all tacks themselves were free of inflammatory cells and degradation. The two tacks remaining in place were tolerated by the posterior segment. After comparing and contrasting our findings with those documented in the rabbit model, we conclude that overcoming dislodgement problems will require improved insertion techniques and tack design.