Abstract: The present invention provides a plug device or grommet (1) for sealing an incision in tissue of a human or animal body, such as an incision in the tissue of the sclera (S) made during a surgical intervention for the implantation of a visual prosthesis. The device (1) comprises: a cover part (10) for covering the incision and an area of the tissue (S) around the incision; and an insertion part (20) extending from the cover part (10) for insertion into the incision through the tissue (S). The insertion part (20) defines a sealable passage (30) which is adapted to extend through the incision, and the insertion part (20) is preferably flexible and resiliency deformable to open and close the sealable passage (30) there-through. The sealable passage (30) extends through the incision to provide communication between an outer side (S0) of the tissue and an inner side (Si) of the tissue. The passage (30) may accommodate a component which provides a connection or interconnection through the tissue (S).