Fibrovascular response to retinal tacks in the rabbit and monkey eye

Abstract

In order to evaluate the tissue response to metal retinal tacks experiments were carried out on 4 monkey eyes and compared to those on 4 rabbits. Non-magnetic retinal tacks (Grieshaber, Switzerland) and tacks made of 24 carat gold (our own brand) were inserted into the ocular fundus under microscopic control. The animals were kept for 3 months. In monkey eyes, histological examination disclosed a considerable fibrovascular proliferation around the retinal tack canal, including an inflammatory response, formation of collagenous tissue and glial proliferation. There was a local intra-retinal and epi-retinal neovascularization. In the rabbit retina, only a slight inflammation and thin collagenous tissue developed. Thus the tissue response was much more severe in the primate eye than in the avascular rabbit retina.

Magnetoactive elastomer as an element of a magnetic retina fixator

“…Retinal tacks caused adverse effects, probably due to excessive trauma. In monkey eyes implanted with retinal tacks, histological examination showed a considerable fibrovascular proliferation around the retinal tack canal, including an inflammatory response, and local intra-retinal and epi-retinal neovascularization [47]. Although there were some cases with favorable eye reaction [48,49], the use of retinal tacks was declined.…”

Angiographic findings following tack fixation of a wireless epiretinal retina implant device in blind RP patients

“…As a matter of fact, in different animal models the insertion of retinal tacks did not cause severe hemorrhages but revealed different glial reactions at the fixation site, as the tissue reactions of primate eyes have been pointed out to be more severe than in rabbit eyes [13]. In detail, the monkey eyes showed a significant infiltration of inflammatory cells and the appearance of CNV around the tack canal, while both animal models have in common that no retinal detachment could be observed.…”

“…As possible alterations we considered on the one hand the possible development of macular edema as a reaction to the tight contact of the stimulator foil with the retinal surface. On the other hand, in animal experiments on primates, choroidal neovascularisations (CNV) have been observed around the tack canal, which may occur in our patients as well [13].…”